• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-05
Javier Serrano; Jesús Acero; Ignacio Lope; Claudio Carretero; José Miguel Burdío

Domestic induction cookers are evolving from fixed cooking areas to flexible surfaces in such a way that the pot can be placed at any position. This implies the use of a larger number of reduced-sized inductors, which present a lower efficiency. As a solution to increase the efficiency while maintaining the flexibility, we propose the use of partially overlapped inductors of a larger size. This concept is currently in use in wireless power transfer systems, where the transmitter arrangement consists of several overlapped coils. The aim of this paper is to evaluate this concept applied to domestic induction heating appliances, with special emphasis in analyzing the effects of introducing the multicoil system with dissipative media. Moreover, the losses in the winding will be studied in detail. The system will be prototyped and tested, delivering up to 3.7 kW.

更新日期：2018-05-27
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-08
Kapil Chauhan; Motakatla Venkateswara Reddy; Ranjana Sodhi

Distribution-level signals are often contaminated with harmonics and noise, along with dynamic conditions like frequency deviations. This paper proposes an empirical wavelet transform (EWT) based M-class distribution-level phasor estimation technique under such polluted and dynamic conditions. The capability of the EWT of extracting different frequency components present in the signal makes it suitable for distribution-level phasor estimation. However, the empirical wavelet filters are designed on the basis of the Fourier spectrum of the signal, which, inturn suffers from a spectral leakage problem at off-nominal frequencies. To avoid the errors arising due to spectral leakage, a sample value adjustment based prefiltering technique is employed. The effectiveness of the proposed estimator is demonstrated on various simulated signals, field-data, and real-time signals obtained from the hardware implementation setup. The proposed algorithm is found to be least affected by the presence of dc components, harmonics, and noise. The use of a fixed window size and fixed sampling frequency makes it suitable for synchronization with GPS clocks. The proposed scheme is also able to provide an accurate harmonic phasor estimation.

更新日期：2018-05-27
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-19

This paper proposes a novel nonisolated single-input dual-output three-level dc–dc converter (SIDO-TLC) appropriate for medium- and high-voltage applications. The SIDO-TLC is an integration of the three-level buck and boost converters, whose output voltages are regulated simultaneously. Reducing voltage stress across semiconductor devices, improving efficiency, and reducing inductors size are among the main merits of the new topology. Moreover, due to the considerably reduced volume of the step-down filter capacitor, a small film capacitor can be used instead, whose advantages are lower equivalent series resistance and a longer lifespan. A closed-loop control system has been designed based on a small-signal model derivation in order to regulate the output voltages along with the capacitors’ voltage balancing. In order to verify the theoretical and simulation results, a 300-W prototype was built and experimented. The results prove the aforementioned advantages of the SIDO-TLC, and the high effectiveness of the balancing control strategy. Furthermore, the converter shows very good stability, even under simultaneous step changes of the loads and input voltage.

更新日期：2018-05-27
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-08
Chenguang Yang; Yiming Jiang; Wei He; Jing Na; Zhijun Li; Bin Xu

For parameter identifications of robot systems, most existing works have focused on the estimation veracity, but few works of literature are concerned with the convergence speed. In this paper, we developed a robot control/identification scheme to identify the unknown robot kinematic and dynamic parameters with enhanced convergence rate. Superior to the traditional methods, the information of parameter estimation error was properly integrated into the proposed identification algorithm, such that enhanced estimation performance was achieved. Besides, the Newton–Euler (NE) method was used to build the robot dynamic model, where a singular value decomposition-based model reduction method was designed to remedy the potential singularity problems of the NE regressor. Moreover, an interval excitation condition was employed to relax the requirement of persistent excitation condition for the kinematic estimation. By using the Lyapunov synthesis, explicit analysis of the convergence rate of the tracking errors and the estimated parameters were performed. Simulation studies were conducted to show the accurate and fast convergence of the proposed finite-time (FT) identification algorithm based on a 7-DOF arm of Baxter robot.

更新日期：2018-05-27
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-05
Jun Song; Yugang Niu; Yuanyuan Zou

This paper addresses the mean-square finite-time bounded control problem for uncertain stochastic systems via a sliding mode approach. The stochastic phenomena of randomly occurring uncertainties and randomly varying actuator faults modeled by two independent exponential distributions are addressed effectively. A key issue for the system under the consideration is how to ensure, for any prescribed finite (possibly short ) working time interval, the stochastic finite-time boundedness (SFTB) of the resultant closed-loop systems and the reachability of the specified sliding surface in mean-square sense. To this end, a parameter-dependent sliding mode control (SMC) law is designed to force ( with probability one ) the state trajectories into a domain around the specified sliding surface during the given finite-time interval. The upper bound of the sliding domain associated with the design parameters is obtained explicitly. The sufficient conditions are established, respectively, for guaranteeing the SFTB of the SMC systems over both reaching phase and sliding motion phase . Finally, the proposed finite-time SMC approach is illustrated via a parallel active suspension system.

更新日期：2018-05-27
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-01-26
Kaixing Huang; Chunjie Zhou; Yu-Chu Tian; Shuanghua Yang; Yuanqing Qin

Industrial cyber-physical systems (ICPSs) are widely applied in critical infrastructures such as chemical plants, water distribution networks, and power grids. However, they face various cyberattacks, which may cause physical damage to these industrial facilities. Therefore, ensuring the security of ICPSs is of paramount importance. For this purpose, a new risk assessment method is presented in this paper to quantify the impact of cyberattacks on the physical system of ICPSs. This method helps carry out appropriate attack mitigation measures. The method uses a Bayesian network to model the attack propagation process and infers the probabilities of sensors and actuators to be compromised. These probabilities are fed into a stochastic hybrid system (SHS) model to predict the evolution of the physical process being controlled. Then, the security risk is quantified by evaluating the system availability with the SHS model. The effectiveness of the proposed method is demonstrated with a case study on a hardware-in-the-loop simulation test bed.

更新日期：2018-05-27
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-02-23
Zipeng Liang; Sideng Hu; Huan Yang; Xiangning He

Converters with impedance source networks combine their one-stage energy conversion with the function as buck and boost converters. Due to this fact, they are very attractive to the dc–ac applications. Many literatures have 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 converters is required. This paper first presents small-signal modeling for the bidirectional quasi-Z-source converter 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 the oscillation in the 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 is demonstrated and the results are in good agreement with the theoretical analysis.

更新日期：2018-05-27
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-01-23
Duc-Tri Do; Minh-Khai Nguyen

In this paper, a three-level quasi-switched boost T-type inverter (3L qSBT2I) is proposed. A new pulse-width modulated (PWM) control method is presented to reduce the inductor current ripple of the qSBT2 I. In the introduced PWM technique, the shoot-through duty cycle is maintained constant to keep the modulation index as high as possible. Then, the only control parameters of the qSBT2I are the duty cycles of the two additional switches. By controlling the duty cycles of the two additional switches, the voltage gain of the proposed qSBT2 I can be improved to a value larger than that of the conventional 3L impedance source inverters. The steady-state analysis, operating principles, and comparisons with the impedance source-based 3L inverters are presented. A 1-kW prototype is constructed to verify the operating principle of the 3L qSBT2I. An indirect dc-link voltage regulator and a capacitor voltage-balance controller are applied to the proposed qSBT2I. Simulation and experimental results are presented.

更新日期：2018-05-27
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Naipeng Li; Yaguo Lei; Tao Yan; Ningbo Li; Tianyu Han

Remaining useful life (RUL) prediction has attracted more and more attention in recent years because of its significance in predictive maintenance. The degradation processes of systems from the same population are generally different from each other due to their various operational conditions and health states. This behavior is defined as unit-to-unit variability (UtUV), which brings difficulty to RUL prediction. To handle this problem, this paper develops a Wiener process model (WPM)-based method for RUL prediction with the consideration of the UtUV. In this method, an age- and state-dependent WPM is specially designed to describe the various degradation processes of different units. A unit maximum likelihood estimation algorithm is proposed to estimate the UtUV parameter according to the measurements of training units, without any restriction to the distribution pattern of the parameter. The UtUV parameter is further updated via particle filtering (PF) according to the measurements of the testing unit. In the particle updating process, a fuzzy resampling algorithm is developed to handle the sample impoverishment problem of PF. With the updated parameter, the RUL is predicted through a degradation process simulation algorithm. The effectiveness of the proposed method is verified through a simulation study and a turbofan engine degradation dataset.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Lei Wang; Chi-Seng Lam; Man-Chung Wong Wong

In this paper, the structure, coordinate control method and parameter design of a hybrid system are proposed for active power injection and non-active power (reactive, harmonic and unbalance power) compensation. The proposed hybrid system consists of a static var compensator (SVC) in parallel with a capacitive-coupling grid connected inverter (CGCI) (SVC//CGCI). In SVC//CGCI, the SVC part is used to dynamic compensate the reactive power and unbalance power, while the low rating CGCI part is used to inject active power, provide harmonic power and a fixed amount of capacitive reactive power. Compared with conventional inductive-coupling grid-connected inverter (IGCI), the CGCI can provide active, reactive and harmonic power with low rating of active inverter part. The cost of SVC part is much lower than that of active inverter part, thus the reduction of inverter rating can lead to a decrease in the total cost of SVC//CGCI. Therefore, the SVC//CGCI can be a cost effective solution for active power injection and non-active power compensation. Finally, simulation and experimental results are provided to show the advantages and validity of the proposed SVC//CGCI in compared with the conventional IGCI and SVC//IGCI.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Yuan Yuan; Yang Yu; Lei Guo

In this paper, a nonlinear active disturbance rejection control (ADRC) scheme is designed to control the pneumatic muscle actuator system. To reflect the impact of the sampling period, a continuous-discrete extended state observer (CDESO) is employed to estimate the so-called total disturbance, which describes the unmodeled complexities. Then, a nonlinear composite controller is used, where the estimates provided by the CDESO act as the feedforward term. The sufficient conditions to guarantee the stability of the CDESO and the overall controlled system are provided, respectively. Finally, a number of practical experiments are conducted on a pneumatic motion platform in order to verify the applicability of the proposed method.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Jiadong Lu; Yihua Hu; Jinglin Liu

The current reconstruction strategies using single current sensor in the motor drives are widely researched. However, the sampled currents do not represent the average values within the modulation period, especially for the asymmetric modulation or asymmetric sampling solutions. This is due to the following two reasons: 1) the detected current values obtained at different sampling points are utilized to calculate the three-phase currents; 2) the detected instantaneous currents are applied to estimate the average current values. In this paper, the current change rates under different action vectors are estimated to compensate these errors in a three-phase four-switch (TPFS) interior permanent magnet synchronous motor (IPMSM) drive with single current sensor. The effectiveness of the proposed strategy is verified by experimental results on a 5kW IPMSM motor prototype, which shows that the current reconstruction errors are reduced after compensation.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Yao Wang; Jianping Xu; Gang Yin

For single-inductor dual-output (SIDO) DC-DC converter operating in continuous conduction mode (CCM), load variation of one output will affect the voltage of the other output, i.e. there exists cross regulation between its two outputs. To suppress the cross regulation of SIDO DC-DC converter operating in CCM, a novel ripple based control technique, called as capacitor current ripple (CCR) control technique, is proposed in this paper. The operation principle of SIDO CCM buck converter and the proposed CCR control technique are presented. The small signal model of CCR controlled SIDO CCM buck converter is established by state space averaging method. Bode plots based on small signal model show that the proposed CCR controlled SIDO CCM buck converter significantly reduces cross regulation and improves the transient performance compared with peak current mode (PCM) controlled SIDO CCM buck converter. In addition, the effect of the variation of loads on the stability of the proposed CCR controlled SIDO CCM buck converter is analyzed by eigenvalue analysis. Finally, experimental results are provided to verify the analysis results.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Min Li; Yu Zhu; Kaiming Yang; Laihao Yang; Chuxiong Hu; Haihua Mu

Iterative feedback tuning (IFT) enables the data-based optimization of feedback controller parameters without the plant model and disturbance model. However, the traditional IFT suffers from a generally slow convergence rate and requires multiple experiments in each iteration, which severely limit its applicability for precision motion industry. In this paper, a new framework for IFT with its focus on the practical applicability is synthesized. Specifically, in order to improve the convergence rate, a novel two-loop iterative algorithm of IFT is proposed by introducing a weighted gradient of the performance criterion. This algorithm seeks to directly minimize the performance criterion instead of its linear approximation in each iteration. Furthermore, an unbiased estimate method of auxiliary variables is developed based on impulse response experiment. These guarantee the proposed approach high convergence rate with less experiments required per iteration. Comparative simulation and experimental results demonstrate that the proposed approach converges much faster than the traditional IFT, and outperforms the model-based approach in terms of the tracking performance. The ease of implementation and effectiveness make the proposed approach highly suitable for industrial applications.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Shunyi Zhao; Yanjun Ma; Biao Huang

Measurements quality is important for process systems engineering. In this paper, an estimation scheme is proposed in the state-space form to monitor the degree of accuracy of measurements within a pre-defined horizon. Under the assumption that all the sensors are uncorrelated with each other, the distribution of measurement noise covariance as well as the distribution of state vector are estimated simultaneously. The key technique is to approximate the true posterior distribution by two independent proposal distributions using the variational Bayesian inference. It is shown that the proposed algorithm provides not only a complete picture of the working status of each sensor, but also satisfied estimates of the hidden states in the presence of faulty signals. Numerical examples with a moving target tracking model and a quadrate water tank experiment are conducted to demonstrate that the proposed method exhibits better performance than the existing methods, and even a small fluctuation of sensors can be accurately captured by the proposed algorithm.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Ignacio Galiano Zurbriggen; Martin Ordonez

Photovoltaic cells require of Maximum Power Point Tracking (MPPT) algorithms to ensure the amount of power extracted is maximized. True seeking, direct duty cycle control MPPT algorithms are a simple and straightforward solution that can provide high tracking efficiency. In these algorithms the duty cycle is traditionally modified to reach a new steady state prior performing a new MPPT iteration. Therefore, the MPPT update period must be larger than the converter's settling time to reach a new steady state, which limits the dynamic tracking performance. This work proposes a novel direct duty cycle control method that does not require the converter to achieve steady state in between MPPT updates. The proposed method benefits from the natural oscillations occurring in the converter to obtain extreme dynamic tracking improvements while maintaining simple implementation with no need of employing temperature or irradiance sensors. The scheme being introduced combines MPPT concepts with large-signal geometric control to achieve a reliable, high-performance solution very suitable for applications with rapidly changing irradiance such as wearable technology and rooftop EV. The theoretical analysis is supported by detailed mathematical procedures and validated by simulations and experimental results.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Yue Zhu; Jiande Wu; Ruichi Wang; Zhengyu Lin; Xiangning He

In Photovoltaic (PV) system, dc-dc power optimizer (DCPO) is an option to maximize output power. At the same time, data links among DCPOs are often required for system monitoring and controlling. This paper proposes a novel power line communication (PLC) method for the DCPOs, in which the data of a DCPO is modulated into the control loop of power converter, and then transmitted through the series-connected dc power line to other DCPOs. In the process of communication, differential phase shift keying (DPSK) modulation and discrete Fourier transformation (DFT) demodulation are employed. To analyze the quality of communication, the communication model of the system is built, based on small-signal model. Furthermore, the noises of the system, including switching, maximum power point tracking (MPPT) and additive white Gaussian noise (AWGN), are discussed and measured to evaluate the signal-to-noise ratio (SNR). At last, an experimental system including 6 DCPOs is established and tested, which verifies the feasibility and effectiveness of the proposed method.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Ya-Hsiang Tai; Chi-Hao Lin; Tsung-Hsuan Ho; Yu-Sheng Huang; Sheng-Miao Huang; Wei-Min Cho

Fully digital driving circuit for thin film transistor liquid crystal display (TFT-LCD) can offer benefits including less power consumption and shortened design schedule. Using the pulse width signal to control the moment to stop the ramp voltage, the pixel voltage can be set accurately. In this paper, the possible issues of power consumption, device non-uniformity, and parasitic capacitance are well studied to prove the feasibility and advantages of the digital driving method. It is prospectively expected to substitute for the conventional analogue driving method in the future.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Yi Du; Chao Zhang; Xiaoyong Zhu; Feng Xiao; Yandong Sun; Yuefei Zuo; Li Quan

This paper investigates a novel 3-phase doubly salient permanent magnet (DSPM) motor. Because of the adoption of ⊓-shaped stator iron core segments, the asymmetrical magnetic circuit among different phases occurring in conventional DSPM motors with E-shaped stator iron core segments can be avoided, so that balanced and sinusoidal 3-phase PM flux linkage and no-load EMF can be achieved. Firstly, based on a 12/7 stator/rotor pole combination, the operation principle of ⊓-core DSPM motor is discussed using the least magnetic reluctance principle. Then the general airgap field modulation theory (AFMT) is extended to the ⊓-core DSPM motor for explaining its operation principle further and armature winding connection. The finite element analysis is used to validate theoretical analysis, as well as to calculate its electromagnetic performances. The results show that the 12/7-pole ⊓-core DSPM motor possesses higher average torque output capability and lower torque ripple compared with the 12/8-pole E-core counterpart. Finally, a 12/7-pole ⊓-core DSPM motor is built and tested so as to experimentally verify the theoretical analysis.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Wei Li; Ming Cheng

In this paper, the quantitative evaluation of flux-switching permanent magnet (FSPM) machine system reliability is carried out based on Markov model. The evaluation model of permanent magnet (PM) machine system consists of six main functional components and their dominant failure modes are counted. The performance of FSPM machine system under each fault is simulated and compared with reliability criteria to judge the reliability state of machine system. The Markov model is used to calculate FSPM machine system reliability. The influence of machine phase number, stator core topology and hybrid excitation method on the machine system reliability is investigated. The experiments are presented to validate the accuracy of fault simulation. The reliability analysis results lay the foundation for the reliability design of FSPM machine.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Manuel Fernandez; Xavier Perpinya; Jose Rebollo; Miquel Vellvehi; David Sanchez; Tomas Cabeza; Sergio Llorente; Xavier Jorda

This work focuses on providing an improved and efficient alternative to Electro Mechanical Relays (EMR) in view of the growing demand characteristics for an effective power multiplexing in induction heating applications. A major analytical approach to the design and implementation of Bi-Directional Switches (BDS) based on different power semiconductor technologies is presented, including thorough static and dynamic characterizations. Emerging Gallium Nitride High Electron Mobility Transistors (GaN HEMTs) and Silicon Carbide (SiC) based devices are identified as potential candidates for the mentioned applications.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Hendrik Vansompel; Anna Yarantseva; Peter Sergeant; Guillaume Crevecoeur

Despite the use of state-of-the-art thermal modeling tools in the design stage, the measured thermal behavior of prototype electrical machines can differ significantly from the modeled ones. This paper shows how a thermal model, based on finite element method, of an electric machine can be improved using inverse modeling techniques. In a thorough study, a forward high fidelity finite element thermal model of a 4kW axial flux PM machine is introduced and improved using inverse modeling techniques via non-collocated thermal sensors. Parametric model order reduction of the high fidelity finite element thermal model based on moment matching method is performed to make the recovery of the actual thermal parameters characterizing the thermal behavior of the axial flux PM machine tractable. Additionally, the same reduced order model is used to identify the different power loss components in the machine. Experimental results confirm that the presented two-stage approach is capable to identify the thermal parameters and losses with high accuracy.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Igor Perin; Geoffrey R. Walker; Gerard Ledwich

Load sharing between feeder stations has the ability to significantly improve the performance of AC electric railways by reducing the number of the traction power network grid connections and minimizing losses and plant sizes. The existing Rail Power Conditioner (RPC) technology, traditionally used for load balancing, is investigated from the new perspective of providing reactive voltage support and active power sharing between stations. The concept is validated through a feasibility study conducted for a heavy haul AC railway network.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Wenkai Gao; Yuejiu Zheng; Minggao Ouyang; Jianqiu Li; Xin Lai; Xiaosong Hu

Micro-short circuit (MSC) is a latent risk in power batteries, which may give rise to thermal runaway and even catastrophic safety hazards. The motivation of this study is to quantitatively analyze MSC in an initial stage, particularly for lithium-ion batteries. To verify the feasibility of the proposed method, an equivalent MSC experiment is carried out. Based on a cell difference model (CDM), the cell SOC differences with the mean SOC for a battery pack are estimated by extended Kalman filter (EKF). The evaluated SOC difference can track the actual value well. Furthermore, a MSC diagnostic method is developed by employing recursive least squares (RLS) filter. The method is demonstrated to examine the short circuit resistance accurately. The results also show that the proposed method requires low computational load for the SOC difference and short circuit resistance diagnosis.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Zhao Zhibin; Shuming Wu; Baijie Qiao; Shibin Wang; Xuefeng Chen

Bearing faults are one of the most common inducements for machine failures. Therefore, it is very important to perform bearing fault diagnosis reliably and rapidly. However, it is fundamental but difficult to extract impulses buried in heavy background noise for bearing fault diagnosis. In this paper, a novel adaptive enhanced sparse period-group lasso (AdaESPGL) algorithm for bearing fault diagnosis is proposed. The algorithm is based on the enhanced sparse group lasso (ESGL) penalty proposed in this paper to promote the sparsity within and across groups of the impulsive feature of bearing faults. Moreover, a periodic prior is embedded and updated dynamically through each iteration of the optimization procedure. Additionally, we form a deterministic rule about how to set the parameters adaptively. The main advantage over conventional sparse representation methods is that AdaESPGL is parameter-free (forming a deterministic rule) and rapid (extracting the impulsive information directly from the time domain). Finally, the performance of AdaESPGL is verified through series of numerical simulations and the diagnosis of a motor bearing. Results demonstrate its superiority in extracting periodic impulses under comparison with other state-of-the-art methods.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Wenhai Qi; Guangdeng Zong; Hamid Reza Karimi

This paper deals with the problem of $\mathscr{L}_\infty$ control for positive delay systems with semi-Markov process. The system is subjected to semi-Markov process that is time-varying, dependent on the sojourn time, and related to Weibull distribution. The main motivation for this paper is that the practical systems such as the communication network model described by positive semi-Markov jump systems (S-MJSs) always need to consider the sudden change in the operating process. To deal with the corresponding problem, some criteria about stochastic stability and $\mathscr{L}_\infty$ boundedness are presented for the open-loop positive S-MJSs. Further, some necessary and sufficient conditions for state-feedback controller satisfying $\mathscr{L}_\infty$ boundedness and positivity of the resulting closed-loop system is established in standard linear programming. Finally, the practical system about the communication network model is given to verify the validity of the proposed method.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24

In this paper, an adaptive method for tuning a Proportional Resonance (PR) controller for synchronization of grid-connected inverters is presented. In the proposed approach, the grid frequency is obtained by minimizing the error signal using a Frequency Locked Loop (FLL) mechanism that consists of a resonant adaptive filter and a perturbation-based extermum seeking algorithm. Simulations and experimental studies are presented to demonstrate performance of the proposed controller in face of frequency variations of an emulated grid voltage waveform. The results are compared with conventional non-adaptive methods, which indicate that performance characteristics for voltage/frequency tracking and power factor can be achieved based on the IEEE 1547 standard.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Yukai Zhu; Jianzhong Qiao; Lei Guo

The requirements for the control performances of space manipulators, especially for the stability and accuracy of the attitude control systems of the base spacecrafts, are ever increasing during the space target capturing tasks. However, the system uncertainties caused by parameter variations will degrade the system performances severely. This paper investigates the precise and fast trajectory tracking control problem for the free-flying space manipulator after capturing a space target with uncertain mass. To compensate the system uncertainty with complex and uncertain dynamics, a novel adaptive sliding mode disturbance observer (ASMDO) is proposed. Then, a composite controller with prescribed transient and steady-state performances is developed. It is proved that the estimation error of ASMDO can be stabilized in finite time though the bound of the derivative of system uncertainty is unknown. Meanwhile, the trajectory tracking error can also be stabilized in finite time and has preassigned maximum overshoot and steady-state error. Finally, numerical simulations and experimental studies are presented to demonstrate the effectiveness of proposed methods.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Shaohua Chen; Gang Liu; Lianqing Zhu

This paper presented a novel sensorless start-up strategy for a 315kW high-speed magnetic suspension brushless DC (BLDC) motor with small inductance and non-ideal back electromotive force (back-EMF). Two key strategies on the sensorless start-up strategy of BLDC motor were presented: (1) small current start-up strategy for the high-speed BLDC motor with small inductance, and (2) self-adaption control strategy to compensate the commutation error for the BLDC motor with non-ideal back-EMF in the start-up stage. A hybrid pulse width modulation (PWM) strategy based on the load torque was proposed to limit the start-up current. An optimal motor start-up curve based on the system parameters was presented, and a self-adaption control strategy was proposed to solve the synchronous switching problem. The effectiveness and feasibility of the proposed method were verified by a series of experiments on the 315 kW-20000 rpm magnetic suspension blower platform.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Khanh Duc Hoang; Hong-Hee Lee

This paper presents an accurate power sharing method to balance the state of charge (SoC) among the distributed battery energy units (BEUs) in a DC microgrid. The virtual power rating concept of the proposed control method is introduced, and accurate power sharing is achieved according to the SoC levels and the virtual power ratings, regardless of the line resistance difference. With the accurate power sharing based on SoC, BEUs with higher SoC accurately supply more power to the system than the lower SoC BEUs during the discharging period and BEUs with lower SoC accurately supply less power to the system than the higher SoC BEUs during the charging period. Moreover, with the voltage restoring method, the DC grid voltage is maintained within the desired voltage level, and with the proposed control method, the system stability is verified. The proposed control scheme is implemented in a distributed manner that relies on low bandwidth communication. The effectiveness of the proposed control method is proved by simulation and experiments.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Li Hong Idris Lim; Dazhi Yang

This paper presents an economic way to implement a high precision (micron level) XY stage motion control for the industrial microscope using DC motors. Other than the prevailing design of using stepper motors where the stage is always locked under the motorized mode, the proposed design allows users to manually move the stage by introducing the friction engagement in between. The nonlinearity from the friction is then fully compensated by the sliding mode control (SMC) so that the stage can strictly follow the predefined motion profile. Possible chattering suppression methods are discussed and the accuracy loss is analyzed using LuGre friction model. Finetuning algorithm is then proposed to limit the absolute position error within 2 microns. Comparing to the other micron-level industrial microscopes using stepper motors, the proposed solution achieves comparable performance with much lower costs.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Kuangen Zhang; Jing Xu; Heping Chen; Jianguo Zhao; Ken Chen

In order to deal with automatic assembly problems for flexible components, we develop contact states analysis, jamming analysis and force control strategies for flexible dual peg-in-hole assembly. Firstly, the contact states in large and small deformation stages are enumerated respectively. Secondly, the relationship between forces and moments is derived, and the jamming states for different stages are analyzed. Thirdly, the control strategies are also presented. Finally, the results of experiments verified the effectiveness of the contact state analysis, jamming analysis and force control strategies.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Zhongze Wu; Z.Q. Zhu; C. Wang; Jean-Claude Mipo; Sophie Personnaz; Philippe Farah

In this paper, the open-circuit DC winding induced voltage in a wound field switched flux (WFSFs) machines is analysed. The phenomenon of open-circuit DC winding induced voltage is illustrated and the mechanism is explained. Rotor skewing is proposed to reduce the open-circuit DC winding induced voltage, and the optimal skewing angle is analytically derived based on the analytically deduced harmonic orders of the open-circuit DC winding induced voltage. Finite element (FE) analyses show that the open-circuit DC winding induced voltages in the analysed 12-stator-pole partitioned stator WFSF machines having 10-, 11-, 13-, and 14-rotor-pole rotors can be effectively reduced by > 94%, whilst the AC winding phase fundamental back-EMFs can be maintained by > 95%. 12/10-stator/rotor-pole prototypes with skewed and non-skewed rotors are built and tested to verify the analytical and FE results.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-24
Edgar Ramirez-Laboreo; Eduardo Moya Lasheras; Carlos Sagues

Several modeling, estimation, and control strategies have been recently presented for simple reluctance devices like solenoid valves and electromagnetic switches. In this paper, we present a new algorithm to online estimate the flux linkage and the electrical time-variant parameters of these devices, namely the resistance and the inductance, only by making use of discrete-time measurements of voltage and current. The algorithm, which is robust against measurement noise, is able to deal with temperature variations of the device and provides accurate estimations during the motion of the armature. Additionally, an integral estimator that uses the start of each operation of the actuator as reset condition has been also implemented for comparative purposes. The performances of both estimation methods are studied and compared by means of simulations and experimental tests, and the benefits of our proposal are emphasized. Possible uses of the estimates and further modeling developments are also described and discussed.

更新日期：2018-05-25
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-18
Seung Jin Chang; J. B. Park

It is important not only to diagnosis the wiring of the vehicle in operation but also to find fault and wire mismatch during the assembly process. We propose a new method combining time-frequency domain reflectometry and deep learning to verify that the wire is connected to the proper port of underhood electrical center. Considering the frequency characteristics of each wire (black, blue, red, yellow), we develop an optimization signal design algorithm. Using the time-frequency cross correlation (TFCC), the reflected signal generated at the impedance discontinuities is acquired and converted into the Wigner-Ville distribution image. Through the proposed algorithm, the existing images are converted into new images which are easy to distinguish among groups. The new images are used as input of convolutional neural network and learned the feature of each group. The lengths, compensation filters, and the port information to be connected each wire are stored in the filter bank. If the derived distance using the TFCC is different from the stored length, the wire is considered defective and the acquired signal is restored by the compensation filter designed by overcomplete wavelet transform method. Experimental results demonstrate the effectiveness of the proposed method for detecting wire mismatch and fault location.

更新日期：2018-05-19
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-17
Ren C. Luo; Tung Jung Hsiao

Indoor localization based on received signal strength (RSS) will result in a decreased precision after the environment changes. In this paper, we develop an adaptive wireless indoor localization system (ILS) for dynamic environments. The system consists of the following two components: an automated database updating process, and a new fingerprinting algorithm called adaptive signal model fingerprinting (ASMF). In the ILS, a self-locating mobile robot is set up to continuously collect RSS measurement within the localization space for autonomously updating fingerprint database. ASMF is designed to reduce the time consumption and the number needed of RSS data for updating database. The fingerprint of the signal in ASMF is constructed by the position of the beacons and three signal models which can be duly corrected based on regression and optimization algorithm. Finally, we propose experiments for positioning targets in the static and dynamic environments, and compare the results of ASMF algorithm with traditional trilateration and k-nearest Neighbors fingerprinting algorithms. The experimental results demonstrate that the ASMF-based ILS provides much better performance in both static and dynamic environments, furthermore, the positioning accuracy can be actually maintained by the autonomous updated ASMF database.

更新日期：2018-05-18
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-15
Abhijit Kulkarni; Sudip K. Mazumder

In this letter, the effect of deadtime in a gallium nitride (GaN) based grid-connected differential-mode Cuk converter (DMCI) with high-frequency (HF) transformer isolation is analyzed. It is shown that different levels of even or odd harmonics appear in the grid current depending on the power factor of operation. Utilizing the leakage inductance of the HF transformer, the deadtime is suitably eliminated to result in an improved grid current THD. Experimental results support the proposed solution.

更新日期：2018-05-16
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Shiwen Xie; Yongfang Xie; Tingwen Huang; Weihua Gui; Chunhua Yang

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Xiao Qiang Guo; Yong Yang; Xuehui Wang

DC-link current ripple is one of the important factors for operating the current source converter. In practice, the dc-link current ripple can be reduced by increasing the switching frequency or inductor. However, it may result in the higher switching losses, larger size or higher cost. In order to deal with this problem, the inherent limitation of the conventional solution is discussed. The time-domain equation of the dc-link current is established for the first time. And then, a new space vector control strategy is proposed to reduce the ripple with no need of increasing the switching frequency or inductance. The space vector is divided into twelve sectors, where the dc-link current ripple can be effectively reduced by the optimal vector sequence. Finally, the proposed method is implemented on the TMS320F28335DSP + XC3400FPGA digital control hardware platform. The experimental results verify the effectiveness of the proposed strategy.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10

Increasing penetration level of distributed generation (DG) necessitates their participation in supporting power system stability and providing ancillary services. This paper highlights the necessity of supporting the connection voltage by these units under short-term unbalanced voltage sags. To address this, a new regulation scheme, named asymmetrical ride-through (ART), is proposed in this paper. The proposed scheme enforces DG units to properly regulate the voltage within the dynamic limits for three important voltage parameters: positive-sequence, negative-sequence, and phase voltage magnitude. The main advantages of applying the ART scheme are avoiding unnecessary outages due to temporary unbalanced faults and enhancing the grid stability. As the second contribution, an advanced dynamic voltage support method is also proposed to accurately address the specifications determined in the ART scheme. The successful results of the ART regulation scheme and proposed dynamic voltage support method are verified using simulation and experimental test cases.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Juncai Song; Fei Dong; Jiwen Zhao; Hui Wang; Zhongyan He; Lijun Wang

This study focuses on the multi-objective design optimization of the permanent magnet synchronous linear motors (PMSLM), which are applied to high- precision laser engraving machine. A novel efficient multi-objective design optimization method for PMSLM is proposed to achieve optimal performance as indicated by high average thrust, low thrust ripple, and low total harmonic distortion (THD) at different running speeds. First, based on the finite element analysis (FEA) data, a regression machine learning algorithm, called extreme learning machine (ELM) is introduced to solve the calculation modeling problem by mapping out the nonlinear and complex relationship between input structural factors and output motor performances. Comparative simulation experiments conducted using the traditional analytical modeling method and another machine learning modeling method, i.e., support vector machine (SVM), confirm the superiority of ELM. Then, a new bionic intelligent optimization algorithm, called the grey wolf optimizer algorithm (GWOA), is applied to search the best optimization performance and structural parameters by performing iteration optimization calculation for multi-objective functions. Finally, FEA and prototype motor experiments prove the effectiveness and validity of the proposed method.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Tohid Nouri; Naser Vosoughi; Seyed Hossein Hosseini; Ebrahim Babaei; Mehran Sabahi

This paper presents an interleaved converter which benefits the coupled inductor and built-in transformer voltage multiplier cell (VMC). Compared with the other converters with only built-in transformer or only coupled inductor, the combination of these techniques gives an extra degree of freedom to increase the voltage gain. The VMC is composed of the windings of built-in transformer and coupled inductors, capacitors and diodes. The voltage stress of MOSFETs are clamped at low values and can be controlled via the turns ratio of the built-in transformer and coupled inductor that increases the design flexibility. Moreover, the energy of the leakage inductances is recycled to the clamp capacitors which avoids high voltage spikes across MOSFETs. In addition, the current falling rate of the diodes is controlled by the leakage inductances and the reverse current recovery problem is alleviated. Meanwhile, due to interleaved structure of the proposed converter, the input current ripple is minimized and the current stress of the power devices are decreased. The principle operation and steady-state analysis is given to explore the advantages of the proposed converter. Finally, a 1.3 KW prototype with 50-600V voltage conversion is built to demonstrate the effectiveness of the proposed converter

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Jundi Jia; Guangya Yang; Arne Hejde Nielsen; Peter Ronne Hansen

The short circuit response of a voltage source converter (VSC) under grid unbalanced faults mainly depends on the design of its control system. Due to the limited semiconductor overload capability, the short circuit current contributed by VSC should be restricted within the limit for each phase. This might bring up challenges to the protection system of a converter-dominated power system. This paper derives a generic peak current limitation method for three different VSC control strategies. The impact of the control strategies and the combined impact of VSC with a synchronous condenser on distance protection are evaluated using a commercial relay through hardware-inthe-loop (HIL) tests. Based on the test results, we propose to avoid using constant reactive power control strategy. It poses adverse impact on the reliability and speed of distance protection regardless of the presence of SC at the point of common coupling (PCC), while constant active power and balanced current control strategies favour the performances of distance protection.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Oliver Niklas Dieterle; Thomas Greiner; Peter Heidrich

This paper proposes a novel approach for the control of a permanent magnet synchronous machine with a quadruple 3-phase star-connected winding configuration after a short circuit-fault in one voltage source inverter. The approach includes an adaption of the closed-loop current control that allows to proceed the operation of the faulty unit without the need to adapt the reference currents. This allows an operation of the faulty drive with increased post-fault mean torque. Additionally, a strategy for post-fault torque error compensation is proposed, which can be used to reduce the torque ripple while the load distribution is better balanced. Results are respectively compared to the case when applying a symmetric short circuit to the faulty unit, which is the conventional strategy in case of a transistor short circuit-fault. The current limit of the drive is considered in all cases. The benefits of the approach are validated through experimental tests.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Enrique Rodriguez Diaz; Francisco D. Freijedo; Josep M. Guerrero; Juan-Alberto Marrero-Sosa; Drazen Dujic

This work presents a design methodology and its experimental validation for the input-admittance passivity compliance of LCL grid-connected converters. The designs of the LCL filter parameters and discrete controller are addressed systematically, and suitable design guidelines are provided. The controller design is developed in the z-domain, with capacitor voltage based active damping used as degree of freedom to compensate for system delay effects. The role of resistive components in the circuit, which have inherent dissipative properties, is also discussed. As an outcome of the design, a passive input admittance shaping is obtained. The theoretical development is further verified in a low-scale prototype supplied from a controllable grid simulator. For the sake of generality, different combinations of resonant to sampling frequency are tested. Experimental results fully prove the input-admittance passivity compliance.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Zhen Zhang; Hongliang Pang; Apostolos Georgiadis; Carlo Cecati

Due to limitations of low power density, high cost and heavy weight etc., the development and application of battery-powered devices is facing with unprecedented technical challenges. As a novel pattern of energization, the wireless power transfer (WPT) offers a band new way to the energy acquisition for electric-driven devices, thus alleviating the over-dependence on the battery. This paper presents an overview of WPT techniques with emphasis on working mechanisms, technical challenges, metamaterials, and classical applications. Focusing on WPT systems, this paper elaborates on current major research topics and discusses about future development trends. This novel energy transmission mechanism shows significant meanings on the pervasive application of renewable energies in our daily life.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Jinguo Han; Jieqiong Lin; Zhanguo Li; Mingming Lu; Jianguo Zhang

This paper reports on mechanical design, optimization, and experimental testing of a novel piezo-actuated elliptical vibration-assisted cutting (EVC) system constructed by flexure hinges. The stroke and natural frequency were analyzed based on the theoretical modeling. An enhanced central composite design was chosen as the design of experiments methodology to reduce the modeling error, and a non-dominated sorted genetic algorithm-II was adopted for structure optimization. The optimized EVC generator was manufactured and experimentally tested to investigate practical properties of the proposed EVC system. It shows that the stroke of input end can reach to 30μm with a motion resolution of 10 nm, and the first natural frequency can reach to 2600 Hz without considering the manufacturing error. Besides, a relatively small cross-axis coupling ratio (within 0.21%) can be effectively obtained. The developed EVC system is advantageous not only to being equipped with machine tools with various configurations, but also to easily achieving arbitrary vibrations in 3-dimensional space through two actuators, which is especially important for the generation of complex structured surfaces. With the present work, it is of great significance to promote industrial application of EVC techniques.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10

In this paper, a space vector modulation (SVM) method for indirect matrix converters (IMCs) is proposed to improve the output voltage quality in high modulation index ratios and to reduce the peak common mode voltage (CMV). A novel approach in the rectifier stage modulation, generates a variable dc-link voltage that is controlled to drive the inverter stage on the limit of the linear modulation during each switching period. This allows inherent formation of the output voltage using only two active vectors per sector, which reduces peak CMV and enhances output voltage quality. Analytical and experimental studies are carried out to validate the feasibility and the benefits of the proposed modulation technique.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Xiao Qiang Guo; Yong Yang; Xue Zhang

There are technical challenges when the grid- connected current source converter operates under unbalanced grid voltage conditions. The negative sequence component of the unbalanced grid voltage would result in the low-frequency ripple at dc side, as well as current harmonics at ac side. It has an adverse impact on the system operation. In order to solve the problem, the system mathematical model is established. The limitation of the conventional control strategy is clearly clarified. And then the improved control strategy is discussed from the viewpoint of constant instantaneous active power. In order to further enhance the system performance, a new control strategy is proposed. Instead of the complicated instantaneous power theory, the proposed solution is a direct control strategy. Both the low-frequency dc-side ripple and ac-side current harmonics can be significantly reduced with a simple control structure, due to the direct control concept. Finally, the comparison evaluation of the conventional and proposed control strategies is carried out. The experimental results verify the effectiveness of the proposed solution.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Avanish Tripathi; G Narayanan

Induction motor drives operated with a low ratio of switching frequency to fundamental frequency (i.e., pulse number) are prone to have high magnitudes of low-order torque harmonics. This paper proposes a method to analytically evaluate the harmonic torque spectrum based on the pulse width modulated voltage waveforms for low pulse number operation. The predicted torque harmonic spectra for different pulse width modulated waveforms are validated through simulations and experiments. This paper also reports optimal switching angles to minimize the total RMS value of torque harmonics of order 6, 12, 18… 6(N-1), considering the number of switching angles per quarter (N) to be 4 and 5. Compared to sine triangle pulse width modulation (ST PWM) and selective harmonic elimination pulse width modulation (SHE PWM) with the same pulse number, the proposed optimal switching angles significantly reduce the total RMS value of all harmonic torques of order lower than 6N. Extensive simulation and experimental results on a 3.7-kW induction motor drive are presented to demonstrate the superior performance of the proposed optimal pulse width modulation (PWM)

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Nikhil Pathak; Ashu Verma; T.S. Bhatti; Ibraheem Nasiruddin

This paper presents the accurate modeling of HVDC links for the dynamic studies of automatic generation control/load frequency control (AGC/LFC) of multi-area interconnected power system. In earlier AGC studies, HVDC links were simply modeled by using the first-order transfer function with system time constant T_dc. It was argued that T_dc is the time required by HVDC links to establish DC current after following a load disturbance in power system. However, no mathematical or analytical justification was provided in support to the existing transfer function model of HVDC links. This paper presents the accurate modeling of HVDC links for AGC studies. The comparative analysis has also been performed to demonstrate error being accrued due to the use of conventional model of HVDC links. Furthermore, this paper also implements the inertia emulation based control (INEC) strategy in AGC which allows to harness the stored energy from the capacitance of HVDC links for AGC operations.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Wentao Huang; Wei Hua; Fangbo Yin; Feng Yu; Ji Qi

To reduce the thrust force ripple of a complementary and modular linear flux-switching permanent magnet machine, a model predictive thrust force control (MPTFC) is developed and implemented based on the active voltage vectors selection (AVVS) and two-voltage-vector synthesis (TVVS). Firstly, the active VVs are screened and assigned to the specific sector, instead of traversing all the possible vectors, and consequently, significantly decrease prediction workload. Secondly, for the elimination of the weighting factor in the conventional MPTFC, the control object is transformed from the thrust force and stator flux to the stator flux only by using the load angle. Thirdly, to achieve the steady-state performance improvement, the TVVS approach is applied in each control period, where the optimal TVVS and its dwell time are simultaneously obtained by only one cost function. Both simulated and experimental results verify that the steady-state performance improvement can be realized by the developed MPTFC through comparing with normal hysteresis current control and conventional MPTFC strategies.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Jian Li; Kai Wang; Feng Li; Shushu Zhu; Chuang Liu

This paper presents a novel consequent-pole permanent magnet (CPM) machine featuring N-S-iron-S-N-iron sequences to eliminate the even-order harmonics in phase back-EMF and the unipolar leakage flux. The flux barrier is employed to improve the symmetry of the airgap flux and reduce the saturation of the stator yoke, and hence the output torque can be improved. The proposed CPM machine, as well as its conventional counterpart with N-iron sequences, is optimized by FE analyses. Moreover, the electromagnetic performance of the proposed CPM machine, including the open-circuit airgap flux density, back-EMF, average torque, torque ripple, loss, efficiency and unipolar leakage flux, is compared with the conventional CPM and SPM machines. Although both the proposed and conventional CPM machines have lower output torque than the SPM machine, the utilization ratio of PM material is increased by >33%. It is demonstrated that the proposed CPM machine has similar output torque and efficiency, but much lower torque ripple compared to the conventional one. Moreover, unipolar leakage flux does not exist in the end shaft of the proposed machine, and thus the magnetization of the mechanical components can be effectively eliminated. Finally, the 9-slot/6-pole CPM machine is prototyped and measured to validate the analyses.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Mingqiao Wang; Ping Zheng; Chengde Tong; Quanbin Zhao; Guangyuan Qiao

With the advantages of good driving performance and high fuel economy, the series-parallel hybrid electric vehicles (HEVs) are widely developed. Power-split device, which is a kernel part of HEV, can be based on planetary gear or compound-structure machine (CSM). The transverse-flux brushless double-rotor machine (TF-BDRM), which can form a CSM by being connected with a traditional permanent-magnet synchronous machine (PMSM), is investigated in this paper. The equivalent magnetic circuits are established, and the equivalent reluctances, and d- and q-axis armature-reaction reactance are deducted. It is found that the armature-reaction reactances are in direct proportion to pole-pair number. The reluctances of stator core, inner and outer air gaps, transverse-flux (TF) tooth and leakage reluctance are analyzed. Flux-concentration structure is investigated to increase the main flux of the machine. Flux-concentration factor EFC is used to illustrate the effect of flux-concentration structure, which can be increased by the increase of the radial and circumferential thickness of PM. The flux-density distributions of two typical situations are simulated. With manufacturing technology investigated, the TF-BDRM prototype is made, and experiments are carried out. The tested waveforms of BEMF are approximately sinusoidal, and the tested torque ripple is obvious.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Xiao Sun; Liming Shi; Zhihua Zhang; Haibin Zhu

Due to dynamic longitudinal end effect, the motor flux is lagging and the thrust is fluctuated in long primary double sided linear induction motor (DSLIM). In this paper, a thrust fluctuation reduction method is proposed for the DSLIM with segmented power supply. The mathematical model of DSLIM module considering the dynamic longitudinal end effect is established first and a new field orientation is presented by solving variation of motor flux when the secondary enters or leaves a motor module. Then the thrust expression is deduced based on the new field orientation, and a coefficient is proposed to present the thrust bias in a single module. The restraint of the thrust bias is implemented by increasing or changing the slip frequency according to the orientation in the movement. The proposed coefficient and the thrust control method are validated by simulation and experiment results.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Yang Li; Weihao Dong; Qingxin Yang; Jingtai Zhao; Liu Liu; Shaojie Feng

In a wireless power transfer (WPT) system via coupled magnetic resonances (CMR), the power transfer efficiency (PTE) drastically decreases with the transfer distance or the load changing. In this paper, the causes of efficiency degradation were analyzed, and an automatic impedance matching method based on the feedforward-backpropagation (BP) neural network was proposed to maintain the PTE at a reasonable level. To validate and test the performance of the proposed method, a WPT automatic impedance matching simulation system was implemented. Moreover, a prototype based on the proposed method was built and dynamic matching experiments were performed. The simulation results show that the algorithm efficiency of the proposed BP method was 108.5% higher than that of the genetic algorithm. The experimental results show that the PTE was improved up to 78.33% and this was closely maintained within a distance of 10 to 30 cm, which is consistent with the simulation result.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Jingjing Huang; Xin Zhang; Zhikang Shuai; Xinan Zhang; Peng Wang; Leong Hai Koh; Jianfang Xiao; Xiangqian Tong

CLLC-type DC transformer (CLLC-DCT) is very popular in the hybrid AC/DC microgrid thanks to its high-power density advantage and good bidirectional power transfer capacity. In the hybrid AC/DC microgrid, the open-loop control is always utilized by the CLLC-DCT to cooperate with the bidirectional interlinking converter to realize the power and voltage conversion between the AC and DC bus. This paper firstly studies the circuit parameters design of the open-loop controlled CLLC-DCT with consideration of such a realistic problem: the real inductors/capacitors values are actually different with their theoretically designed values due to the operation power and temperature variation. To solve this problem, a robust circuit parameters design scheme is proposed for the CLLC-DCT in this paper. With the proposed scheme, the designed CLLC-DCT exhibits good power transmission and voltage regulation ability in the hybrid AC/DC microgrid even when its actual inductors/capacitors values vary with the practical power and temperature. The robust design method is experimentally verified in a hybrid AC/DC microgrid prototype.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Jun Young Yoon; Jeffrey Lang; David Trumper

We present the design of a novel low-noise high-force linear motor for precision positioning applications such as in semiconductor lithography. The paper presents new magnetic designs to achieve low noise and vibration by reducing high spatial-frequency magnetic field components, which cause harmonic vibrations of a moving stage. To reduce such force harmonic content, our new motor has fine teeth, narrow slots with high slot aspect ratio, five phases, and a moving skewed Halbach magnet array. As compared with a commercially-available iron-core motor, in our new design the acoustic noise level in Pascals is reduced by more than 90 %, corresponding to a 20 dB reduction in sound pressure level, even with a non-skewed magnet array. Using a skewed magnet array, the cogging-driven and velocity-dependent noise is further reduced by 90 % in Pascals. This new linear motor simultaneously is capable of very high shear force densities in order to support high-acceleration motions, and thus provides new options for high-performance and quiet linear motion devices.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Yi Liu; Wei Xu; Jianguo Zhu; Frede Blaabjerg

The standalone brushless doubly-fed induction generator (BDFIG) has demonstrated excellent energy saving performance in ship shaft power generation applications. As a standalone system, it exhibits unbalanced terminal voltages and poor performance under unbalanced loads. However, the existing control scheme of grid-connected BDFIGs cannot be directly applied to stabilize the amplitude and frequency of terminal voltage when the rotor speed and electrical load vary. This paper presents a new sensorless control scheme for the standalone BDFIG under unbalanced load conditions in the ship shaft power generation system. A second-order generalized integrator based quadrature signal generator is introduced to realize the rotor speed observer for the standalone BDFIG feeding unbalanced loads. The compensation method of negative-sequence power winding voltage is proposed to eliminate the negative-sequence component of the unbalanced power winding voltage. Comprehensive experiments are carried out on a prototype BDFIG with and without the compensation of negative-sequence power winding voltage. The good performance of the proposed sensorless control scheme is verified by the experimental test results.

更新日期：2018-05-11
• IEEE Trans. Ind. Electron. (IF 7.168) Pub Date : 2018-05-10
Haijun Xu; Wenxin Huang; Feifei Bu; Haozhe Liu; Xiaogang Lin

Dual stator-winding induction generator (DWIG) is attractive in stand-alone power system, and the aim of this paper is to develop the dc generating system of five-phase DWIG with an open phase. Firstly, the relationship between flux and torque is constructed based on the reduced-order transformation, modified flux and current. Secondly, the relation between modified voltage and current on dq plane is constructed. The current of fundamental plane is used for the control loop of the power-winding voltage and control-winding voltage, respectively. Thirdly, the current of modified secondary subspace plane is used to control the five-phase DWIG operation at min control-winding loss. Finally, the simulation and experimental results are given to verify that the amplitude of phase current and output voltage can be regulated effectively by the proposed control strategy.

更新日期：2018-05-11
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.