• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Yuanqing Wu; Hamid Reza Karimi; Renquan Lu

In this paper, the intelligent devices in industrial manufacture are modeled as the nodes in the network systems. The sampled-data control is adopted to guarantee the synchronization of the network systems. The proposed sampled-data control strategy can reduce the updating frequency of the controller and the network communication burden. The closed-loop system is equivalently rewritten as the feedback interaction of a linear time-invariant system (LTI) and a time-delay operator. The small gain theorem (SGT) is utilized to calculate the upper bound of the sampling intervals. Furthermore, the integral quadratic constraints (IQC) can provide the passivity-type property of the operator and give the less conservative results. Moreover, in order to further use the information about the sampling pattern and sawtooth structure, the time-delay integral operator is replaced by sample-data integral operator. And the less conservative results are proposed. Finally, the effectiveness of the proposed sampled-data distributed control strategy is demonstrated by a numerical example.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Rodrigo de Toledo Caropreso; Ricardo Augusto Souza Fernandes; Diana Pamela Moya Osorio; Ivan Nunes da Silva

In this paper, it is proposed a structured methodology to define the architecture for a communication framework with multi-frame capability, which can be embedded in a residential smart meter hardware for Smart Grid applications. This framework is based on TCP/IP protocol, and it is considered that data is exchanged via wireless. The architectural model was based upon the state of the art in Software Engineering, making use of Design Patterns and the principles of low coupling and high cohesion which result in a solution that is both, more reliable and maintainable. A security module is also provided and the framework performance is evaluated, in terms of packet throughput and computational effort of the security layer on the processing device, via practical experiments of some laboratory scenarios. Furthermore, errors on some frames are introduced in order to evaluate the feasibility of this framework in real field applications. Results show that this framework architecture supports acceptable transfer rates even with extra computational cost due to the use of data encryption and separated processing modules, making it a feasible proposal for the considered application context.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Baharak Akhlaghi; Hosein Farzanehfard

This paper presents a family of ZVT interleaved DC/DC converters. Soft switching operation for all power semiconductor devices in the proposed topologies is achieved by using one auxiliary circuit with only one auxiliary switch. Therefore, the proposed converters have a simple structure with low size and cost. The proposed converters can achieve zero voltage soft switching operation for the main switches and zero current soft switching operation for the auxiliary switch. In addition, the reverse recovery problem of the diodes is alleviated. Therefore, the losses associated with semiconductor components are reduced and efficiency is improved considerably. Besides, no extra voltage and current stresses are imposed on the main switches in comparison with hard switching counterparts. Operation principles and design considerations of an interleaved boost converter with the ZVT auxiliary circuit are discussed in details. A prototype of this converter is implemented and tested to validate the theoretical analysis and converter operation.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Donghua Pan; Liyi Li; Mingyi Wang

The key technology of the Air-core monopole linear motor (AMLM), a core component of precision motion systems, is distribution of the electromagnetic structure and cooling structure, thus AMLM can achieve small thrust fluctuation, high thrust density as well as motor surface temperature rising performance. Consequently, the multi-objective optimal design of AMLM under the multi-physical fields has become the key technology of AMLM. The surface magnetic charge model and image method are proposed in the paper to establish an air gap magnetic field model of AMLM. The saturation characteristic of magnetic materials can be reflected through saturation coefficient of the model. An AMLM thermal field model is established by adopting the thermal network method. In the model, the heat transfer coefficient of cooling water is calculated based on the current curve obtained from the FEA software. Parametric modeling was performed on the AMLM electromagnetic and cooling structure through definition of seven dimensional proportionality coefficients. Genetic algorithm (GA) was adopted for AMLM optimization design by setting cooling capacity and size as constrain conditions. The AMLM electromagnetic field, accuracy of thermal field model and validity of the AMLM optimization method were verified through simulation and tests.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Yongzhi Zhang; Rui Xiong; Hongwen He; Michael Pecht

The current lithium-ion battery remaining useful life (RUL) prediction techniques are mainly developed dependent on offline training data. The loaded current, temperature, and state of charge of lithium-ion batteries used for electric vehicles (EVs) change dramatically under the working conditions. Therefore, it is difficult to design acceleration aging tests of lithium-ion batteries under similar working conditions as those for EVs and to collect effective offline training data. To address this problem, this paper developed a RUL prediction method based on the Box-Cox transformation (BCT) and Monte Carlo (MC) simulation. This method can be implemented independent of offline training data. In the method, the BCT was used to transform the available capacity data and to construct a linear model between the transformed capacities and cycles. The constructed linear model using the BCT was extrapolated to predict the battery RUL, and the RUL prediction uncertainties were generated using the MC simulation. Experimental results showed that accurate and precise RULs were predicted with errors and standard deviations within, respectively, [μ20, 10] cycles and [1.8, 7] cycles.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Lei Li; Kok-Meng Lee; Kun Bai; Xiaoping Ouyang; Hua-Yong Yang

This paper presents two methods to derive an inverse model in harmonic forms for analyzing the interactions between the torque and currents, and for suppressing the torque ripples of a multiphase permanent magnet motor. The first method directly calculates the desired current harmonics from a pseudo-inverse model of a multiphase PM motor with no input voltage saturation, which is independent of its rotor displacements, for torque ripple compensation. The second is an iterative-free method formulating the inverse model as an optimization problem that minimizes the copper loss subject to torque constraints while accounting for the effects of input voltage saturation. The formulation and significance of the two methods are illustrated with a multiphase PM motor for which published measurements are available for model validation and compared with three other commonly used current waveforms for benchmark comparison in terms of torque-ripples and copper losses.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Gan Zhang; Wei Hua; Peng Han

Hybrid-excited flux-switching machines based on permanent magnet flux-switching machines were proposed to achieve improved torque-speed characteristics. However, due to the reduction of PM volume, decreases in torque density and efficiency are usually inevitable. Thus, it is necessary to make a comprehensive comparison between the dual-three-phase hybrid-excited flux-switching machines and their permanent magnet flux-switching counterparts. To obtain a full understanding of flux-switching machines, permanent magnet flux-switching machines with U-shaped stator cores and alternate-pole magnets or C-shaped stator cores are considered. From the perspective of the frequency domain, this paper not only gives a comprehensive evaluation and comparison of the abovementioned six flux-switching machines, but also reveals the theoretical mechanism that results in their different electromagnetic behavior in a unified way by the general field modulation theory, which is the main contribution of this paper.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Rogerio Luiz Silva Junior; Telles Brunelli Lazzarin; Ivo Barbi

A direct three-phase AC-AC converter based on the switched capacitor principle and ladder structure is presented in this paper. Additionally, the boundary between partial charge and no charge modes of switched-capacitor operation is defined. All switched-capacitor direct AC-AC converters described in the literature employ four-quadrant switches; however, the proposed structure works with two-quadrant switches. This characteristic is the main advantage of the proposed structure because it reduces the number of MOSFETs employed in the power circuit, increasing the converter reliability. Furthermore, the proposed converter can operate as a step-up or step-down circuit, i.e., it is a bidirectional topology. The converter offers high performance with regard to efficiency, power density and power factor, and it can also be used as an electronic autotransformer. The analysis, design methodology and experimental results obtained with a prototype with 220/110 V and 3.5 kW are described herein. At the rated power an efficiency of 95.1% for step-up and step-down modes, capacitive power factor of 0.94 and output voltage regulation of 96% were obtained.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Jiang Weidong; Lei Wang; Jinping Wang; Xuewei Zhang; Peixia Wang

Virtual space vector pulse width modulation (VSVPWM) for the neutral point (NP) clamped (NPC) three-level inverter (TLI) is briefly reviewed as well as its carrier-based realization. The carrier-based VSVPWM (CB_VSVPWM) is featured with dual modulation waves and a single carrier. Although CB_VSVPWM can make NP voltage unfluctuating in theory, it hasn't the NP voltage recovery ability. In practice, due to the effect of non-idea factor, NP voltage may shift. Thus, active NP voltage control (ANPVC) is necessary. To achieve that, three ANPVC approaches are proposed based on CB_VSVPWM in this paper. The NP voltage control ability of CB_VSVPWM with ANPVC is analyzed. At last, comprehensive experiments are carried out to verify the feasibility of the proposed method.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Jun Wang; Xu Han; Hao Ma; Zhihong Bai

The circulating current of modular multilevel converter (MMC) has a great impact on the power losses, the submodule capacitor voltage ripples and the rating of power devices. Existing analysis of circulating current has considered the capacitor voltage. In this paper, the effect of semiconductor devices on the circulating current is further presented. In order to realize the different circulating current injection targets under different conditions, a unified on-line calculation scheme by using the instantaneous information of MMC is proposed to generate the circulating current injection references. It avoids detecting the amplitude and phase of the output current or using an extensive lookup table. Besides, a concise analysis model is built and it reveal the impact on the capacitor voltage ripple and the RMS value of arm current with different injection references, thus guide the determination of the injection ratio. Experimental results based on a three-phase MMC prototype with 6 submodules per arm are presented to demonstrate the analysis of circulating current and the proposed circulating current injection references generating method is verified by different circulating current control targets with different loads.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Rafa Lajara; Juan Jose Perez Solano; Jose Pelegri Sebastia

The lifetime of wireless sensor networks deployments depends strongly on the nodes battery state of health. It is important to detect promptly those motes whose batteries are affected and degraded by ageing, environmental conditions, failures, etc. There are several parameters that can provide significant information of the battery state of health, such as: the number of charge/discharge cycles, the internal resistance, voltage, drained current, temperature, etc. The combination of these parameters can be used to generate analytical models capable of predicting the battery state of health. The generation of these models needs a previous process to collect dense data traces with sampled values of the battery parameters during a large number of discharge cycles under different operating conditions. The collected data allow the development of mathematical models that can predict the battery state of health. These models are required to be simple because they must be executed in motes with low computational capabilities. The article shows the complete process of acquiring the training data, the models generation and its experimental validation using rechargeable batteries connected to Telosb motes. The obtained results provide significant insight of the battery state of health at different temperatures and charge/discharge cycles.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Shuze Zhao; Ibrahim Ahmed; Vaughn Betz; Ashraf Lotfi; Olivier Trescases

The Power Delivery Network (PDN) between the voltage regulator and the FPGA core must be carefully designed to achieve a low output impedance over a broad range of frequencies. Simulation tools are commonly used to estimate the decoupling impedance, however they do not account for aging, component variations and inaccurate modelling of parasitic elements, all of which lead to PDN design deviation. In this work, two schemes are presented, 1) to extract the DC resistance in the power delivery path, and 2) to identify the high impedance frequency band(s) in the PDN. The embedded impedance extraction tool is synthesized within the FPGA load, in coordination with a mixed-signal current-mode dc-dc converter. A new self-calibrated Carry-Chain based ADC (CC-ADC) is used for high-speed sampling of the core voltage. The proposed schemes are demonstrated on an Intel Cyclone IV FPGA board. Real-time IR-drop compensation is shown to eliminate logic errors in an FIR filter application. It is also shown that the fail/pass map of a CrossBar application matches well with the extracted impedance. By modifying the PDN based on the extracted results, the voltage operating range and reliability of the CrossBar application is greatly extended.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Kun Bai; Ruoyu Xu; Kok-Meng Lee; Wang Dai; YongAn Huang

This paper presents the concept of a spherical-motor-based motion platform (SMP) for providing high performance nozzle-substrate negotiation in conformal printing of curved electronics. Unlike conventional motion systems using serially/parallel mechanisms for multi-DOF rotations, a ball-joint-like spherical motor for providing continuous 3-DOF rotations in one joint is designed to meet the special needs of conformal printing process. Both the kinematic and dynamic models of the SMP are presented for fitting into the conformal printing process. Specifically, the performance of a spherical motor has been evaluated, which shows better negotiation capability of the SMP than traditional motion systems. The experimental test results performed on a prototype spherical motor have validated the design concept.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Zipeng Liang; Sideng Hu; Huan Yang; Xiangning He

Convertors with impedance source networks combine their one-stage energy conversion with the function as buck and boost convertors. Due to this fact they are very attractive to the dc-ac applications. Many literatures has focused on the stress analysis and control enhancement of the impedance network in the dc side. For a better system design and control, the synthesis and interaction principle between the ac and dc side of the convertors is required. This paper firstly presents the small signal modeling for the bidirectional quasi-Z-source convertor by the circuit-averaging technique. Compared with previous modeling based on the shoot through duty ratio, the modulation ratio is included for the ac side analysis. It is revealed that oscillation in modulation ratio could be triggered by the ac current controller, due to the magnitude margin issue caused by the impedance network. And then instability in the impedance network can be observed, including the system input current. Based on the theoretical analysis, a design guideline for the ac current controller is provided. Experimental validation for both the model and analysis are demonstrated and the results are in good agreement with the theoretical analysis.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Ebrahim Babaei; Hamed Mashinchi Maheri; Mehran Sabahi; Seyyed Hossein Hosseini

In this paper, a new non-isolated high step-up dc-dc converter is proposed. Active-passive inductor cells (APICs) is used to extend the topology. The ability to achieve high gains is the main merit of the proposed topology. The proposed converter operates based on parallel charging and series discharging of the inductors. The converter also achieves high step-up voltage gain with appropriate duty cycle and low voltage and current stress on the power switches and diodes. The proposed converter is analyzed in operation modes. The main parameters of the converter such as voltage gain, voltage stress of semiconductor devices are calculated to compare with other structures in literature. Considering the output voltage ripple and filter size, the proposed converter is designed. Moreover, the losses and efficiency of the converter are calculated. The performance of the proposed converter is validated by experimental results.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Jiepin Zhang; Jianqiang Liu; Jingxi Yang; Nan Zhao; Yang Wang; Trillion Zheng

A LLC-LC type bidirectional control strategy for LLC resonant converter is proposed in this paper. It can achieve bidirectional power flow automatically without any power flow detection procedures. Meanwhile, the soft-switching can be always guaranteed all the time. In order to adapt to the proposed control strategy, a no-load-point-based design method is put forward in this paper, which can rapidly obtain optimal parameters of LLC resonant converter. What's more, by using the proposed control strategy, the starting characteristic in no-load condition can be improved, output voltage rising and current surge risk can be avoided. Finally, an experimental platform of power electronic traction transformer (PETT) power cell (consisted of a single phase rectifier and a bidirectional LLC resonant converter) is built to verify the validity of the proposed control strategy.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Xiuyun Zhang; Tingna Shi; Zhiqiang Wang; Qiang Geng; Changliang Xia

In order to overcome the redundancy of the biaxial motion system's traditional control structure and the cumbersome nature of the controller parameter adjustment, this paper simplifies the traditional control structure, and proposes a generalized predictive contour control strategy applicable to biaxial motion system based on the idea of unified modeling. The two permanent magnet synchronous motors (PMSMs) that drive biaxial motion system are considered as a whole to establish a unified model. Through the idea of multi-step prediction, rolling optimization and feedback correction in generalized predictive control, the optimal control input signal is obtained by coordinating the tracking error and contour error. In addition, an actuating value limitation has to be taken into account to design a realizable generalized predictive contour control for the biaxial system. At the same time, the closed-loop stability analysis of the generalized predictive contour control system is carried out according to the optimal control principle and the state equation model. The experimental results show that the proposed control strategy can not only accurately track the contour trajectory at steady state, but also improve the transient contour tracking performance.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Min Chen; Dehong Xu; Tao Zhang; Keyan Shi; Guofeng He; Kaushik Rajashekara

Grid-connected inverters without isolation transformer usually have certain amount of dc component injected to the ac grid due to current sensor error, tolerance of power switching device, asymmetry of PWM gating driving pulses etc. Many efforts, such as using blocking capacitor, current dc component feedback control and voltage dc component feedback control have been introduced to try to suppress the dc injection to the grid. This paper proposes a novel control strategy of suppressing dc current injection to the grid for three-phase inverter by accurately sensing the DC component of line voltages of three-phase inverter and adding a DC component control loop. DC suppression control scheme is presented. The suppression performance of the proposed DC rejection method is evaluated and compared with the traditional method. Finally, the control scheme is verified on a 20kW three-phase grid-connected inverter.

更新日期：2018-02-24
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Saleh Ziaeinejad; Younes Sangsefidi; Ali Mehrizi-Sani

The granular multilevel converter (GMC) is a multilevel converter built by hybridizing a conventional twolevel converter with an asymmetrical cascaded H-bridge (A-CHB) converter. Addition of each additional H-bridge submodule doubles the number of the GMC output voltage steps. Thus, with a small number of power electronic switches and associated gate drive signals and circuits, a GMC can offer a high-quality AC voltage to meet the stringent requirements of high-performance drives and gridtied converters in low- and medium voltages. This paper proposes 1) a generalized switching strategy to control the output voltage as well as capacitor voltages of Hbridge submodules for a GMC with an arbitrary number of submodules n. This proposed strategy is scalable, which allows for easy modification of the voltage rating or the number of the voltage steps of the GMC, and 2) a systematic analysis for optimal sizing of the submodule capacitors to minimize the required total energy of the installed capacitors. Simulation and experimental case studies evaluate the performance of the proposed switching and capacitor sizing algorithms.

更新日期：2018-02-17
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Chun Gan; Qingguo Sun; Nan Jin; Leon M. Tolbert; Zhibin Ling; Yihua Hu; Jianhua Wu

This paper proposes a simple and cost-effective current measurement technique for four-phase switched reluctance motor (SRM) control, by splitting the dual bus line of the converter, without pulse injection and voltage penalty. Only two hall-effect sensors are utilized, where one is installed in the upper bus to measure two phase currents, and another one is placed in the lower bus to measure another two phase currents. In order to realize independent current measurement in the whole turn-on region, switching functions are redesigned so that upper switches of two phases act as the choppers, while lower switches of the other two phases are employed as the choppers. Compared to traditional drives, the developed system requires only two hall-effect sensors in the dual bus line, without a need for individual phase sensors or additional devices, which reduces the cost and volume for SRM drives. Furthermore, compared to the single-sensor based current measurement scheme, the proposed method has no need to implement pulse injection and will not cause any voltage penalty and current distortion, which also improve the current measurement accuracy and system performance. Simulation and experiments carried out on a 150-W four-phase 8/6 SRM confirm the effectiveness of the proposed technique.

更新日期：2018-02-15
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Xing Zhang; Haoyuan Li; Shuying Yang; Mingyao Ma

In permanent magnet synchronous motor (PMSM) drive system, high-frequency (HF) pulsating voltage signal injection has demonstrated high accuracy to estimate the initial rotor position. However, conventional signal demodulation method may face the problems of long convergence time and limited system stability, owing to the low pass filter (LPF) used in signal demodulation process. Thus a direct signal demodulation method is proposed, in which, the LPF is removed to improve system stability and dynamic property. A direct demodulation collection is generated to extract the position deviation signal from estimated q-axis HF current. Recursive discrete Fourier transform (RDFT) is employed to calculate the amplitude of estimated d-axis HF current, thus an amplitude normalized technique is implemented to reduce the effects of HF signal and PMSM. Meanwhile, the stability and dynamic property are compared between the conventional and proposed method, with the aid of D-partition technique and amplitude-frequency characteristics diagram. Furthermore, a novel magnetic polarity detection method is put forward based on the magnetic saturation, which has a high signal-to-noise ratio (SNR). Finally, the experimental results on three PMSM drive systems prove that the proposed method is practicable and effective.

更新日期：2018-02-15
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-10-30
Qi Zhu; Mei Su; Yao Sun; Weiyi Tang; Aiguo Patrick Hu

The low coupling coefficient between the transmitter and receiver is the major constraint of a wireless power transfer (WPT) system. Although some approaches, such as increasing the quality factor and achieving precise impedance matching, can reduce the adverse impacts of the low coupling coefficient and improve the system performance, high leakage magnetic flux between the transmitter and receiver remains a problem. With the increase of transfer distance and the misalignment between the transmitter and receiver, the increasing leakage magnetic flux of non-directional fields degrades the WPT system performance. This paper proposes an active field orientation method to shape the magnetic flux so as to minimize the leakage flux. The amplitude and phase angle of the magnetizing current are controlled, and a coil structure for minimizing the coupling among the transmitters and generating a three-dimensional magnetic field is proposed. This method realizes three-dimension full-range field orientation with adjustable magnitude and direction of B-field at an arbitrary point, and as a result the B-field is concentrated with reduced leakage magnetic flux. The proposed field orientation shaping technique is verified by theoretical analysis, simulation and experimental results.

更新日期：2018-02-15
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Deshang Sha; Jiankun Zhang; Jiawen Wu

This paper introduces a novel BCM controlled micro-converter for PV application in order to provide high conversion efficiency over a wide input voltage operating range. Within the wide input range for the PV panel, there is no need to change the operating modes according to the PV panel voltage. The leakage inductance current can work in boundary conduction mode with fixed switching frequency. The operation mode analysis is given first. Then the operating principle of the proposed boundary conduction mode and its implementation are introduced. Loss breakdown of the prototype using GaN devices is analyzed and compared with same voltage rating silicon MOSFETs. A 300W micro-converter was fabricated and experimental results are provided to verify the effectiveness of the proposed BCM control.

更新日期：2018-02-15
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Ashutosh Trivedi; Mukhtiar Singh

The proposed work is mainly focused to achieve stable operation of microgrid having reconfigurable architecture leading to huge variation in network parameters. The variation in network parameters may not be easily handled by conventional droop controllers which are mainly designed while assuming fixed network configuration. However, these assumptions become invalid for a microgrid having small mesh network with reconfigurable structure. Therefore, it is most important for a microgrid to remain stable not only during various changes in droop characteristics but also during dynam-ic topological changes. The L1 controllers are well known for their robustness under wide parametric variations. Therefore, a novel L1 adaptive controller has been designed to achieve enhanced stability of microgrid under the varying network configuration and variable droop controller characteristics. The proposed method is simulated in MATLAB/ Simulink and verified on FPGA based real world hardware platform.

更新日期：2018-02-15
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-17

In trasformerless grid-connected photovoltaic (PV) systems, common-mode voltage (CMV) fluctuations cause leakage current flow through the stray capacitance of the PV panels. Shoot-through (SH) states in a quasi-Z-source inverter (q-ZSI), increase the amplitude of high order harmonics of CMV. In this paper, by using the modulation technique based on odd PWM (OPWM) and minor change in the Z network of the three-phase q-ZSI, the leakage current is blocked. No extra semiconductor element is added. By the proposed technique, CMV is kept nearly constant during switching cycles. The experimental results for CMV analysis in a 1kW prototype are presented to verify the theoretical analysis.

更新日期：2018-02-15
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-01
Nagesh Geddada; Yew Ming Yeap; Abhisek Ukil

DC system has come a long way to shift the direction of power transmission in future. With respect to that, the protection is still one of the hot topics that need to be addressed, particularly the DC fault detection method. This paper presents methods to robustly differentiate between load change and DC fault in a two terminal DC system connected to passive load. In the first method, wavelet transform is used to determine the wavelet coefficient of the system DC line current. The performance of wavelet transform is compared with the rate of change of current (di/dt) method. Details regarding synchronous reference frame dq current controller at source terminal, RMS (root mean square) method controller at load terminal are discussed. Simulation studies are carried out on Matlab/Simulink model and the corresponding steady-state, load change and fault studies results are presented. Experimental validation of wavelet fault detection method is performed on the developed laboratory DC grid setup interfaced to dSPACE 1103 controller through Matlab real time toolbox.

更新日期：2018-02-15
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-16
N Sandeep; Udaykumar R Y

This paper presents a nine-level active-neutral-point-clamped (ANPC)-based multilevel inverter (MLI) topology for grid-connected applications requiring only ten switches. The envisaged structure comprises two parts, namely five-level ANPC unit, and a two-level converter leg whose midpoint is used as another ac terminal. An ad hoc switching state redundancy-based modulation strategy is used to ensure that the voltage across the flying capacitor is tightly balanced and is implemented using a look-up table further simplifies the control complexity. The performance and effectiveness of the proposed topology with its control scheme are validated through simulations and experimental tests. Comparison with other MLIs is included to highlight the merits of the proposed topology. From the results, it will be shown that the proposed inverter requires the least part count as compared to other topologies with the same performance and output quality

更新日期：2018-02-15
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-16
Jingjing Huang; Bo Yang; Fanghong Guo; Zaifu Wang; Xiangqian Tong; Aimin Zhang; Jianfang Xiao

In this paper, a priority sorting approach based on simplified model predictive control (MPC) is proposed for modular multilevel converter (MMC). It aims at reducing the computational burden of conventional MPC method while maintaining the system performance, especially under high voltage-levels. The proposed approach mainly consists of three parts, i.e., grid-side current control (GCC), circulating current control (CCC) and capacitor voltage balancing control (CVBC). The GCC and CCC are separately designed with simplified MPCs, avoiding the weight factor. Meanwhile, the redundant calculations are eliminated in GCC by considering the desired predicted output voltage of equivalent MMC model. To further minimize the optional combinations of the switching states, the CCC is constructed by utilizing the output of GCC and the arm current. Besides, a novel priority sorting approach is proposed for the CVBC to alleviate the sorting operation. The sub-modules are divided into three groups according to the detected capacitor voltages. Moreover, the groups are assigned with different priorities based on the arm current, and only one group needs the sorting process. Additionally, a reduced frequency approach is introduced to decrease the power loss in the steady-state. The effectiveness of the proposed approach is validated by both simulation and experimental results.

更新日期：2018-02-15
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Walid R. Issa; Ahmad H. El Khateb; Mohammad A. Abusara; Tapas K. Mallick

This paper presents a microgrid control strategy to unify the control topology for energy storage systems (ESS) and renewable energy sources (RES) inverters in an AC microgrid and to protect the microgrid reliability from unintentional islanding instability using control loops which use the DC link voltage as a feedback. This bounds the DC link voltage and provides reliable operation in the microgrid. Simulation validates the proposed control strategy, and experiment results extol the concept.

更新日期：2018-02-15
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Lei Sun; Wei Yin; Meng Wang; Jingtai Liu

This paper presents a position control scheme for flexible joint robot (FJR) based on online gravity compensation (OGC). After concluding some drawbacks of OGC based PD control law, a nonlinear state feedback controller is designed, where analysis for overshoots of motor side and residual vibration of link side is provided. It is shown that asymptotic stability is guaranteed, and each signal of closed loop system is proved to be bounded via Lyapunov method. Comparing experiment results illustrate effectiveness of the proposed approach.

更新日期：2018-02-15
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-10-27
Lanyu Zhang; Jian Gao; Xin Chen

A macro-micro composite precision positioning stage is mainly used in microelectronics manufacturing to achieve high-velocity and high-precision positioning. The residual vibration caused by high-speed macromotion will prolong the settling time and influence the working efficiency. This paper proposes a rapid dynamic positioning (RDP) method to quickly reduce the settling time of a macro-micro positioning stage by employing a designed spring-piezoelectric microstage. The main points of the RDP method are that it can start up the microstage at appropriate moment with proper extension to work against the macromotion vibration. Once the stage vibration amplitude is reduced to the piezoelectric element stroke limit, the micromotion is actuated to approach its final position. In this study, the start-up conditions and extension amount of the piezoelectric element were determined for implementing the RDP method. The feasibility of the method was clarified through theoretical analysis, including dynamic modeling, natural frequency analysis, and a vibration reduction and error compensation analysis. The experimental work was carried out, and the results validated the effectiveness of the RDP method in settling time reduction at different movements. With the assistance of the RDP method, the macro-micro high-speed, large-stroke stage can achieve an effective settling time reduction without sacrificing its accuracy.

更新日期：2018-02-15
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Lei Wang; Chi-Seng Lam; Man-Chung Wong

In this paper, the structure, modeling, parameter design, and control method are proposed for a new hybrid structure of a static var compensator in parallel with a hybrid active power filter (SVC//HAPF). The SVC part of the SVC//HAPF is used to dynamically compensate the reactive power. And, the HAPF part is used to provide harmonic power and small amount of reactive power compensation. Due to the large fundamental voltage drop on coupling the LC part, the active inverter part of the SVC//HAPF has low voltage rating. Meanwhile, the parallel-connected SVC acts as a current divider to reduce the active inverter current. Therefore, the proposed SVC//HAPF shows the great promise in compensating harmonic current and wide-range reactive power with a low (both) voltage and current rating active inverter part. To show the advantages of the proposed SVC//HAPF, simulation comparisons among the active power filter (APF), HAPF, SVC in series with HAPF (SVC−HAPF), and the proposed SVC//HAPF are provided. Finally, experimental results based on the laboratory-scaled hardware prototype are given to show the validity of the SVC//HAPF.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
June-Seok Lee; Hyun-Woo Sim; Juyong Kim; Kyo-Beum Lee

This paper analyzes the combination in a cascaded H-bridge multilevel inverter (CHBI) based on transformers with the different turn ratios for increasing the voltage level and proposes the switching method for achieving the output voltage distribution among H-bridge cells (HBCs). The transformers used in this paper are connected to the output of the respective HBCs, and the secondary sides of all the transformers are connected in series for generating the final output voltage. Only one of the transformers, in particular, has a different turn ratio for increasing the output voltage level. In this paper, the possible turn ratio of the special transformer with a different turn ratio is discussed in detail, and a switching method based on the level-shifted switching method for the topology used in this paper is proposed. To verify the effectiveness of the proposed method, a three-phase 21-level CHBI is experimentally tested.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-10-27
Georgios Konstantinou; Gabriel J. Capella; Josep Pou; Salvador Ceballos

Interleaved converter legs are typically modulated with individual carriers per leg and phase-shifted pulse width modulation (PS-PWM) as it facilitates current balancing amongst the legs. Phase-disposition PWM (PD-PWM), despite the better harmonic performance, cannot be directly used due to the resulting current imbalance that may damage the converter. This paper addresses the current sharing issue and proposes a sorting algorithm implementation that enables single-carrier PD-PWM technique for interleaved two-level converter legs. An extension of the proposed algorithm through a switching state feedback loop, limiting the average switching frequency, is also developed. In both cases, the output current is of high quality and shared amongst the phase-legs, while the deviation between the phase-leg currents is well regulated. Simulation results demonstrate the general function of method for multiple interleaved legs as well as its current sharing capabilities for high-power applications. Experimental results from a low-power laboratory prototype validate the operation of the proposed approach.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Christopher M. Donaghy-Spargo; Barrie C. Mecrow; James D. Widmer

This paper explores the leakage inductance of a single-tooth wound synchronous reluctance motor and its influence on motor performance. It is shown that the stator leakage inductance heavily influences the true saliency ratio in synchronous reluctance motors and a large stator leakage inductance has a serious detrimental impact on the operating power factor. It is also shown through analytical and finite element analysis analysis that synchronous reluctance motors with single-tooth windings suffer an inherent high stator leakage inductance that is dominated the air-gap harmonic leakage component, derived from the significant stator MMF harmonics experienced with this winding type. This explains for the first time the experimental results showing a low operating power factor compared to a distributed wound machine. Measurement of the stator leakage inductance is attempted on a prototyped machine and the standardized method is found to be lacking when single-tooth windings are employed.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-10-30
Sara Roggia; Francesco Cupertino; Chris Gerada; Michael Galea

In this paper, the use of conical induction machines is proposed for an in-wheel traction application. Such machines offer a rotational movement combined with a translational motion of the rotor. The horizontal movement is essential when active engagement and disengagement of the motor from the wheel without any extra mechanical component is required. This paper first investigates the basic concepts of how the conical machine functions and then proposes a mission strategy for a relevant traction application. A detailed description of the full scheme is given. In order to achieve the required performance, an innovative control method for both degrees of freedom of the machine (i.e., torque production and axial movement) is proposed and validated against a small-scale demonstrator of the whole system.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-10-30
Jiadong Lu; Xiaokang Zhang; Yihua Hu; Jinglin Liu; Chun Gan; Zheng Wang

This paper proposes a new phase current reconstruction scheme without using null switching states for interior permanent magnet synchronous motor (IPMSM) sensorless control. The phase currents are independently reconstructed and no additional test voltage pulses are required. First, the principle of the basic phase current reconstruction for IPMSM drive system is analyzed in detail. Then, an independent phase current reconstruction scheme without using null switching states is proposed. The current reconstruction dead zone is divided into six sectors, and each sector is split into three parts with corresponding vector synthesis methods. Meanwhile, the null switching states, $V_{000}$ and $V_{111}$ , are removed from the proposed scheme. In this case, the zero vector is synthesized by the other available vectors. Finally, the reconstructed three-phase currents are utilized for high frequency sine-wave voltage injection-based position estimation. The effectiveness of the proposed scheme is verified by experimental results on a 5 kW IPMSM motor prototype, which shows that the reconstructed phase currents track the actual currents accurately under different working conditions.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-17
Likun Wang; Weili Li

The electromagnetic and heat issue is the core of the key problems for large synchronous generators. This paper presents a new method to account for the rotary excitation field of a large synchronous generator using a new 3-D static frequency-domain finite element to solve the end magnetic field and electromagnetic losses via phase transformation. The solution time is significantly reduced. Both magnetic flux leakage and temperature testing of the end structures are conducted. There is good consistency between the theoretical simulation and the experimental results for both magnetic and thermal fields. The regularity of the magnetic and thermal field distributions is studied drawing on the electromagnetic and heat transfer theories.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Bangcheng Han; Xu Liu; Ziyuan Huang; Xu Zhang; Yinfeng Zhou

Temperature rise caused by losses is a key issue for a high-speed machine. This paper deals with loss calculation and thermal analysis of a high-speed magnetically suspended PM machine (MSPMM) with an actual power of 33 kW and rotation speed of 55 332 r/min. The temperature distribution based on the finite element method is obtained by accounting for various losses, which consist of air friction losses, copper losses, and iron losses of a radial magnetic bearing, a combined radial/axial magnetic bearing, and high-speed permanent magnet machine (PMM). A back-to-back test setup with two MSPMM is fabricated for verifying the calculation results. The predicted maximum temperature of rotor is located in the center of the cylindrical permanent magnet, and the value is 143 °C. Except for the rotor, the estimated maximum temperature of the stator parts is located in tooth tips of the motor stator core, the value is 92 °C, and the error between the predicted temperature and the measured one is 9.3%. Total measured losses are 1644.4 W, the estimated total losses are 1536.7 W, the error is 6.5%, and the efficiency of the machine under test is 94.6%. The loss calculation and thermal analysis results are verified by the measured ones.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-10-02
Fu Lin; Shuguang Zuo; Wenzhe Deng; Shuanglong Wu

In this paper, the characteristics of the electromagnetic noise radiated by an external rotor in-wheel motor (IWM) are investigated with the Doppler effect taken into consideration. First, Maxwell stress tensor method is employed to derive electromagnetic forces on the magnet surface. The effect of common current harmonics is also analyzed. Then, a structural model of the rotor is built and modal test is conducted to validate the model. Nodal forces, which are calculated by finite element method, are transferred from the electromagnetic mesh to the structural model for further vibration prediction. Finally, boundary element method is used to calculate the noise radiated by the rotor. In particular, the Doppler effect is considered. The calculated results are validated by the noise test. It is found that the end cap contributes more to the overall noise than the shell, and obvious sound directivity appears in the noise of the IWM. The noise measured perpendicular to the outer end cap is larger than that measured in other directions. In addition, the Doppler effect would induce additional side-frequency components around high-frequency peaks in the external rotor motor.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-10-30
Yuan Fang; Tong Zhang

High-frequency components of acoustic noise radiated by the electric powertrain make the subjective perception of electric vehicles worse than expected under certain operating conditions. In order to investigate the influence of acoustic components on sound quality, a pulse width modulation (PWM)-fed electric powertrain is studied in this paper. First, the acoustic noise of the electric powertrain is collected in a semianechoic chamber. Then, two types of acoustic components of the electric powertrain, namely harmonic order noise and switching noise, are distinguished through the analyses of supplied current from the inverter and gear vibration. Furthermore, the relationship between subjective perception and spectral characteristics of the noise is discussed, based on which sensitivity is established. Subsequently, the contributions of acoustic components to psychoacoustical parameters are determined. After that, a sound quality model of the acoustic noise radiated by the electric powertrain is established. The comparison between jury test and prediction shows that the established model can be used for sound quality evaluation of the electric powertrain. Finally, the influences of harmonic order noise and switching noise on subjective perception are discussed. The main original contribution of this paper concerns the influences of harmonic order noise and switching noise radiated by PWM-fed electric powertrain on sound quality.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
K. J. Pratheesh; G. Jagadanand; Rijil Ramchand

Multilevel inverters (MLIs) have replaced conventional two-level inverters for medium-voltage high-power industrial applications. One of the best modulation techniques for MLIs is the space vector modulation (SVM). Although SVM has its own advantages, it has been overlooked for much simpler carrier-based modulation schemes in the industry. Nearest level modulation (NLM) is a simple alternative, which is functionally similar to SVM. In this paper, a new generalized SVM algorithm is presented, in which the SVM is achieved using the concept of NLM. A generalized switch matrix is introduced to derive gate pulses for the inverter, which further simplifies the algorithm. The algorithm is tested and verified for a three-phase, three-level, and five-level neutral-point-clamped inverters in both simulation and hardware.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-10-27
Mousam Ghosh; Pradip Kumar Saha; Goutam Kumar Panda

This paper proposes a novel fuzzified mechanical sensorless speed estimation technique for permanent magnet direct current (PMDC) brushed motor operated with pulse width modulation (PWM) based terminal voltage. For replacement of conventional mechanical speed sensors, few mechanical sensorless speed estimation techniques have been reported recently in the field of PMDC brushed motor. In this paper, a novel technique is applied over a recently reported semianalytical dynamic time-domain PMDC brushed motor model incorporating space-domain effects, namely slotting effect and commutation phenomenon to simulate the proposed estimation process. Ripple and back electromotive force based standalone estimation approaches are hybridized in order to eliminate uncertainties in all regions of estimation. In this paper, a discrete fuzzified hybrid speed estimation model has been proposed with adequate dynamic simulation responses. Further the proposed discrete speed estimation model has been applied experimentally over a PWM-driven 24-V, 12-teeth, 100-W PMDC brushed motor and various dynamic real-time responses have been compared with conventionally captured speed samples to validate the proposed model.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-20
Zheng Wang; Xueqing Wang; Ming Cheng; Yihua Hu

In this paper, the remedial operation of switch faults will be investigated comprehensively for T-type-three-level-inverter-fed dual three-phase motor drives. The open-circuit switch faults in multiple phase legs are discussed at first. The faulty conditions are classified into five categories. Different remedial strategies, namely Type-I to Type-V schemes, are proposed for different faulty conditions. In particular, three kinds of Type-III fault-tolerant control schemes are proposed by using medium-voltage vectors to synthesize small-voltage vectors, in such a way that the mid-point voltage in a dc link can be stabilized well. Then, the short-circuit faults in both clamping switches and half-bridge switches are investigated. By analysis, their operation conditions are equivalent to conditions loss of both P and N voltage levels and open-phase faults, respectively. Thus, the corresponding remedial strategies can be applied accordingly. Particularly, a voltage compensation control method is proposed for conditions, where open-switch faults coexist with open-phase operation induced by short-circuit faults in half-bridge switches. The validity of all of theoretical analysis and the proposed remedial strategies has been verified by experiments.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-10-30
Xiaoqiang Guo; Rui Zhong; Mingshu Zhang; Desheng Ding; Weifeng Sun

This paper proposes a new method for fast radial vibration computation in switched reluctance motors. Only a piecewise first-order linear function is used to calculate the total peak acceleration, which is rather fast. The overall radial vibration is the superposition of natural oscillation of each mode. Before that, several critical parameters need to be calculated or measured in advance, including weight factor, natural frequency and damping ratio of each mode, in order to obtain the respective analytical expression of natural oscillation of each mode. First, the total peak acceleration concerning the multiple of current and its slope is derived analytically from the perspective of abrupt change of radial force. Then, a simple method for calculating weight factors is presented for the distribution of peak acceleration of each mode from the total peak acceleration. Natural frequencies are measured and compared by three methods, including finite-element analysis, hammer impulse test, and dc pulse excitation. The calculation of damping ratio is improved since the traditional damping ratio calculation method cannot be used in a multiple degree-of-freedom system. Finally, both simulation and experiments are conducted to verify the effectiveness and accuracy of the proposed method.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Junhua Chen; Jian Li; Ronghai Qu; Meng Ge

This paper proposes a magnet-frozen-permea-bility finite-element method and an experimental approach for inductance analysis of a variable-flux permanent magnet machine. The machine studied uses Alnico magnets, whose nonlinear magnetic properties deteriorate the inductance calculation accuracy. Besides the machine core permeability is frozen, the magnet-frozen-permeability approach freezes nonlinear B–H curves and nonlinear permeabilities of the magnets in the finite-element analysis. Because the soft magnets have low coercive force, conventional symmetric inductance measurement currents may demagnetize them. This paper presents a zero-start dc-biased current trajectory tracking approach. This approach uses positive current, which avoids demagnetization during the inductance measurement. Meanwhile, based on flux linkage-current curves, influences of resistance can be eliminated. Cross-magnetization effects are evaluated in the two proposed methods. Inductances of these two methods are compared and show good agreements.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-09-26
Lesan Wang; Mingyan Wang; Ben Guo; Zhe Wang; Di Wang; Yanlin Li

In order to effectively suppress surplus torque, realizing high precision loading, this paper applies proportional resonant (PR) control to the load torque control of electric load simulator (ELS), and analyzes and optimizes the stability and dynamic performance of ELS. The mathematical model of ELS is built in z -domain first in this paper, to establish foundation for designing and analyzing PR controller. The stability of the ELS with PR controller is analyzed through Nyquist diagrams, and optimized by reasonably designing the phase compensation angle of PR controller. The dynamic performance is analyzed through pole–zero plots, and the resonant gain of PR controller is designed based on the pole–zero plots to optimize the dynamic performance. Experimental results on ELS are provided, and the proposed method is compared with other typical methods, validating the effectiveness of the proposed method.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Guohai Liu; Yu Zeng; Wenxiang Zhao; Jinghua Ji

This paper proposes a new design method for surface-mounted permanent magnet machines. The key to the proposed method is that all rank harmonics are introduced to the permanent magnet for torque improvement. The proposed method can offer a variety of magnet topologies by injecting various harmonics into magnets, and these magnet topologies are subsequently analyzed to select the best one. To find the optimal torque output requires investigating the effect of all rank harmonics on the average torque and the torque ripple, and then determining the optimal harmonic combination. The results show that the fundamental, third and fifth harmonics, make great contributions to improving torque quality, while the seventh harmonic and those with higher orders are insignificant for torque improvement. Finally, a prototype, which employs the proposed method, is measured for validation.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Sze Sing Lee; Michail Sidorov; Nik Rumzi Nik Idris; Yeh En Heng

Cascaded H-bridge (CHB) multilevel inverters (MLIs) have been widely used for power electronics systems. While high-voltage blocking across power switches is not a constraint for low voltage applications, the research trend has been oriented to the design of more compact module topologies as an alternative for CHB. Despite the generation of more voltage levels with reduced switch count, the existing module topologies in recent literature take no account of the freewheeling current path during dead-time, thus, inducing multistep jumps in voltage levels and giving rise to undesirable voltage spikes. Addressing this concern, this paper proposes two symmetrical compact-module topologies for cascaded MLI, where freewheeling current path during dead-time is provided for smooth transition between voltage levels to prevent voltage spikes. The proposed 7-level and 13-level compact-modules demonstrated low number of conducting switches for all voltage levels. Comprehensive analysis and comparison with the latest module topologies are conducted. To validate the operation of the proposed compact-module topologies, simulation and experimental results are presented.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-10-19
Danting Xu; Chi Kwan Lee; Sitthisak Kiratipongvoot; Wai Man Ng

In this paper, an active electromagnetic interference (EMI) choke for both common-mode (CM) and differential-mode (DM) noise suppression is proposed. Three isolated windings with a different number of turns are wound on the same magnetic core. One of the windings is served as the auxiliary winding connecting to an active circuit called the negative impedance circuit. The inductance of the EMI choke is substantially boosted up to effectively attenuate the low-frequency noise. This technique leads to a greater inductance but fewer turns and smaller size of the EMI choke. Different from the design of a conventional EMI filter, which uses separated CM and DM chokes, this proposal saves the cost and space of the EMI filter. The enhancement to the CM and DM impedance is individually analyzed and experimentally confirmed. Based on the classical CM and DM noise models, CM and DM noise insertion losses are predicted using computer simulation. The simulation results are validated by a network impedance analyzer. Finally, conducted EMI tests are carried out to verify the effectiveness of the proposed technique.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Shouxiang Li; Kang Xiangli; Keyue Ma Smedley

A comprehensive analysis for a family of two-level pulsewidth modulation plus phase-shift (PPS)-modulated-isolated-bidirectional dc–dc converters is presented in this paper. Compared with the traditional phase-shift control, the PPS control features reduced current stresses, reduced conduction losses, guaranteed zero-voltage switching (ZVS) operation, and wide conversion-ratio variation range. In this paper, all eight operation modes are revealed, and then the unified solution of the power transmission capability for each mode is proposed, applicable for any two-level PPS converters. Based on the unified solution, component stresses and ZVS operation are analyzed to assist component selection. Most importantly, the control maps for three different combinations of the two-level PPS converters are proposed, to assist converter operation and design in the low-circulating-current region. In the control map, a circuit parameter k is proposed and its upper limit is found, providing a design limit to select switching frequency, leakage inductance, turns ratio, and power level. A 29–67 V/380 V prototype—the combination of group C plus group A—rated at 100–1000 W was built. The analysis is verified by both simulation and experimental results.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Shao Yong Zheng; Zhao Wu Liu; Xiu Yin Zhang; Xin Yu Zhou; Wing Shing Chan

Total bandwidth of existing wireless communication technologies covers a wide frequency range of over one octave. But most existing power amplifier configurations cannot meet this requirement while at the same time maintaining a high efficiency. Therefore, a new structure that can achieve multioctave bandwidth is proposed in this paper together with the design methodology. The difficulty in realizing a bandwidth larger than one octave lies in the overlapping of fundamental and harmonic frequencies. Regarding this problem, the continuous class-F mode is extended to allow a resistive second harmonic impedance, rather than the pure reactive one. With the relaxed design requirements and overlapping design space of fundamental and second harmonic frequencies, harmonic tuning and fundamental frequency matching networks can be designed separately. More importantly, broadband matching for fundamental frequencies can be implemented simply by considering only three fundamental frequency points using the multiple frequencies matching method. To verify the validity of the proposed methodology, a multioctave power amplifier was designed, fabricated, and measured. Measured results verify a wide bandwidth of 128.5% from 0.5 to 2.3 GHz. Over this frequency range, drain efficiency was larger than 60% with output power greater than 39.2 dBm and large signal gain larger than 11.7 dB.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Jin-Guk Kim; Guo Wei; Man-Ho Kim; Ju-Yong Jong; Chunbo Zhu

In the magnetic resonant wireless power transfer (WPT) technology, system topology is the main factor that determines the WPT characteristics of the system, and recently, various system topologies based on various composite resonant circuits are being applied in WPT applications. This paper groups the composite resonant circuit-based WPT systems into one family and conducts a comprehensive investigation on their topologies and characteristics. First, characteristics of the composite resonant circuits, which are the fundamental circuits of transmitter and receiver of these systems, are investigated; in the process, a calculation method of resonant frequency, current ratio, and quality factor of these circuits are presented and the characteristics of these parameters are clarified. Second, based on that, the composite resonant circuit-based WPT systems are investigated. Possible topologies of these systems are explored and an equivalent system model of these systems is proposed. Based on that, characteristics evaluation expressions of these systems are derived and the optimal design guide of these systems is discussed. Finally, experimental prototypes are constructed and the proposed theory is verified by experiment results.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Jan M. Schellekens; Henk Huisman; Jorge L. Duarte; Marcel A. M. Hendrix; Elena A. Lomonova

Practical switching devices have finite turn-on and turn-off times. To avoid short circuit, a blanking time is added between turn-off and turn-on of the complementary working switches in a switching-leg. The blanking time, also referred to as deadtime, is one of the dominant sources of output current and voltage distortion in pulse-width modulated (PWM) power amplifiers. Extensive studies exist on elimination, minimization, and compensation of the effect. Most techniques achieve a reduction of the distortion but are not capable of completely removing it. The dual-buck (DB) converter does not suffer from blanking-time-related distortion. However, blanking time is not the only source of switching-leg-induced distortion. This paper focuses on the effects of semiconductor device parameters on the output quality of the DB converter. It is shown that, ideally, the forward voltages of the diodes and switches have no effect on the output quality. Measurements on a prototype, industrial power stack based, DB converter show a 100 times improvement of the open-loop spurious free dynamic range when compared to conventional PWM converters.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Shanshan Jin; Donglai Zhang; Chao Wang; Yu Gu

Space solar array simulators (SSASs), which are used for testing space power systems, generally utilize linear power topologies owing to their fast dynamic performance and satisfactory simulation accuracy. However, to output a medium power level from a linear-power-topology SSAS, multiple parallel linear voltage-controlled current sources are required for addressing the redundant power dissipation, thereby limiting the overall mechanical structure and volume optimization; in addition, the presence of multiple parallel sources results in a complex circuit structure with poor reliability. In this context, in this study, we propose a novel three-port linear power composite transistor as a linear power dissipation device, which is composed of multiple cascaded SiC-JFETs to improve on the above-mentioned shortcomings. The proposed 510-W optimized SSAS requires only eight parallel linear current-source paths to form a linear power stage and uses a high-speed field-programmable gate array (FPGA) digital controller to quickly react to a load step between short circuit and open circuit (the harshest working condition for a solar array simulator) at a 1-kHz stepping frequency. Further, the device can react to a load step between short circuit and the nominal working point at 10-kHz stepping frequency, thus, offering a better dynamic performance over other similar devices.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Rodrigo Padilha Vieira; Leandro Tomé Martins; Jorge Rodrigo Massing; Márcio Stefanello

This paper proposes a multiloop framework for current control of grid-connected voltage source inverters (VSIs) with LCL output filter. The discrete-time model is of third-order with a nonminimum phase zero when controlling the grid side current. This poses some difficulties on the design of most types of controllers. Motivated by this problem, the inner loop is implemented by a discrete-time sliding mode control law to ensure the tracking of the converter side current. This can be achieved regardless the grid impedance and voltage, making the converter to behave like a current source inverter with a capacitive+inductive ( CL ) filter. Thus, the problem of current control falls from a third-order system to a second-order system. Several types of controllers can be designed to implement the outer loop based on the equivalent CL circuit. In this work, a resonant controller with a virtual resistor was applied. Simulations and experimental results are presented to validate the proposal.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-08-25
Haoze Luo; Wuhua Li; Francesco Iannuzzo; Xiangning He; Frede Blaabjerg

This paper proposes the adoption of the inherent emitter stray inductance $L_{{\rm{eE}}}$ in high-power insulated gate bipolar transistor modules as a new dynamic thermo-sensitive electrical parameter (d-TSEP). Furthermore, a family of 14 derived dynamic TSEP candidates has been extracted and classified in voltage-based, time-based and charge-based TSEPs. Accordingly, the perspectives and the implementation challenges of the proposed method are discussed and summarized. Finally, high-power test platforms are designed and adopted to experimentally verify the theoretical analysis.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13

In inverter-based microgrids, individual inverters operate usually with their own digital processor. The clocks used to generate the time signals of these processors differ from each other due to clock drifts. This paper analyzes the impact that the drifts of the processors clocks produce on the operation of inverter-based islanded microgrids. Several communication-free secondary control schemes, which avoid well-known problems caused by digital communication networks, are considered. Active power sharing and frequency regulation are the metrics used to evaluate the performance of the control schemes. The study reveals advantages, drawbacks, and practical limitations of the control schemes caused by the clocks drifts. Therefore, it facilitates the selection of the most suitable control scheme for the practical deployment of microgrids. The theoretical results are validated by experimental tests in a laboratory microgrid equipped with three inverters and three digital signal processors driven by autonomous internal clocks.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Alexander Bessman; Rudi Soares; Sunilkumar Vadivelu; Oskar Wallmark; Pontus Svens; Henrik Ekström; Göran Lindbergh

Sinusoidal ripple-current charging has previously been reported to increase both charging efficiency and energy efficiency and decrease charging time when used to charge lithium-ion battery cells. In this paper, we show that no such effect exists in lithium-ion battery cells, based on an experimental study of large-size prismatic cells. Additionally, we use a physics-based model to show that no such effect should exist, based on the underlying electrochemical principles.

更新日期：2018-02-14
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2017-11-13
Swen Bosch; Jochen Staiger; Heinrich Steinhart

Voltage source inverter based active power filters are widely used for the compensation of harmonic currents, especially in industrial environments. Loads such as three-phase diode rectifiers, thyristor-based rectifiers or variable-speed drives can cause relevant harmonics up to the 50th order or even higher, depending on the line filter. Usually, the control of the harmonics is either done in multiple rotating frames, where the harmonics appear as dc values, or by resonant controllers in a stationary frame. At this, the calculation effort is rising with the number of harmonics to compensate. In this paper, a predictive current control scheme is presented. It is implemented in addition to common PI current control and used for a three-phase four-wire LCL -filter-based active power filter. Inaccuracies in the model caused by parameter variations are compensated by an additional control structure. Both structures are related only with low computational effort and are not depending on the desired number of the harmonics to compensate. Experimental tests are demonstrating, that both structures individually, and especially the combination of both, are offering a very good behavior in the steady state and in the case of load changes.

更新日期：2018-02-14
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.