With great pleasure, we would like to present the Special Section on Multilevel Converters as an Enabler for Grid Modernization of the IEEE Transactions on Power Electronics (TPEL), which focuses on the research and development of multilevel converters in modern power grids. On the one hand, we investigate the implementation of grid-supportive services and novel control schemes provided by multilevel

Wireless power transfer (WPT) technology has become a developing trend with the advantages of flexibility and security. However, WPT systems also face some challenges, such as output power fluctuations caused by misalignment or dynamic charging, accurate modeling of high-order systems, system integration, load estimation, and simultaneous transmission of power and data. Therefore, advanced topologies

Switched capacitor converters (SCCs) have been widely investigated and used in both academia and industry for many years, ranging from low power (milliwatt level) to high power (several kilowatt levels) for a myriad of applications. SCCs offer several advantages, including the elimination of inductor and related magnetic design issues and hence low electromagnetic interference (EMI), better form factor

To enhance the output power level of wireless charging applications, multiphase inverters are usually required to work in parallel. Even though the same pulsewidth modulated signals are applied for the corresponding switches, there can still be phase differences in the driving pulses, which directly turn on/off the switches, due to the inconsistency in the switch parameters or driving circuits. The

Presents corrections to the paper, (High Power X-band Monolithic GaAs PIN Balanced Limiter).

Grid-forming inverters (GFMI) are prone to have small-signal stability problems when connected to a stiff ac grid. Such stability problems originate significantly from the absence of GFMI control adaptivity to the varying short-circuit ratio (SCR). To confront this challenge, this letter proposes an intelligent synchronous power control (SPC) scheme that is robust against a wide range of SCR of the

Single-wire power transfer (SWPT) can achieve a similar effect as wireless power transfer by using inherent facilities as the transport media, and the different selection of the transport media can lead to a great difference in the system transfer efficiency. In this article, the electromagnetic properties, structural variations, and bending variations of the transport media in the system are investigated

High-frequency inductive power transfer systems can be designed for operation with high tolerance to misalignment and large air-gaps, making it possible to operate in highly dynamic environments. Most examples in the literature use a single active transmitter and a single passive receiver (active–passive approach). Such systems are limited to unidirectional power flow and are susceptible to detuning

The modular multilevel converter (MMC) will be subjected to transient impacts, such as switch operation in gas-insulated switchgear and wall bushing flashover, resulting in MMC submodules' ports suffering from fast transient overvoltage (FTO), posing a threat to the safe operation of power devices. This letter proposed an FTO suppression method using gap- RC as an additional snubber circuit and provided

The short-circuit fault ride-through capability of the inverter directly affects the reliability of the independent power supply system under short-circuit faults. Many existing short-circuit current-limiting strategies of three-phase inverters only ensure that the inverter outputs the fault current to trip the faulty branch circuit breaker during the fault period. This leads to interruption of power

This article develops a general and comprehensive ac analysis to study the optimal condition of a multitransmitter (TX) and multireceiver (RX) coupler. Based on the practical demands, a standard optimization problem is defined and solved by the Lagrange multiplier method. This article would analytically discuss the optimal coupler condition, discuss its physical meaning, and build a uniform perspective

This article proposes a reduced ferrite inductive power transfer (IPT) system for electric vehicle (EV) charging using ferrite-based soft magnetic composites (SMCs). IPT pads typically consist of a significant amount of ferrite to improve field shaping for better magnetic coupling between the primary and the secondary pads. However, the costly and brittle nature of ferrite leaves the IPT pads vulnerable

Impedance characteristics of power converters are dependent on operating conditions, posing challenges to the stability-oriented design of control systems. This is because constant control parameters, designed according to a limited number of operating conditions, may cause instability in other conditions. In this letter, a deep reinforcement learning-assisted framework is proposed to achieve multiobjective

This article presents an optimization of a 6.78-MHz inductive power transfer (IPT) system for unmanned aerial vehicles (UAVs). First, in order to mitigate the impact of the misalignment between the transmitting coil and the receiving coil on the output power and system efficiency, a homogeneous-flux transmitting coil was developed. The optimal allocation of turns of the transmitting coil for generating

With the rapid increase of power consumption in data centers, the 48 V power delivery architecture is introduced, where a two-stage dc–dc power conversion solution is commonly adopted. Four-switch buck–boost (FSBB), as a topology with both voltage step-up and step-down capabilities, is very suitable for implementation as a front-end preregulation module. In this article, the quasi-peak current control

Inductive-power-transfer (IPT) is widely used in wireless charging of electric vehicle (EV). However, the output power and efficiency of the IPT system are often affected by misalignments. In this article, a double-side- LCC ( DLCC ) compensation network with switch-controlled-capacitors IPT topology is proposed to improve the misalignments tolerance for EV. First of all, the output power models of

The large integration of modular multilevel converters (MMC) has introduced stability issues. The impedance-based stability analysis method is widely adopted, where the impedance model can be directly achieved at the terminals through nonintrusive measurement, which facilitates the black-box stability analysis of the MMC–grid interaction system. Yet, due to the limited impedance data amount in the

The application of duty cycle-based finite control set model predictive control (FCS-MPC) to the six-switch converter (SSC), a reduced switch count multiport converter, faces the drawback of an asymmetrical and limited set of voltage vectors, which deteriorates the quality of the system currents. To overcome this issue, this article proposes an FCS-MPC technique with duty cycle optimization for a wind

The active distribution networks have a tendency to develop toward hybrid ac–dc systems constructed by power electronics, the magnitude and direction of power may change randomly at any time, making the usual protection potentially insensitive, raising the negative impacts of single-phase ground (SPG) fault which accounts for the majority of all faults that occurred in medium-voltage (MV) distribution

Carrier-based discontinuous pulsewidth modulation (PWM) is widely used in three-level ac/dc converters due to its features of higher efficiency and simpler implementation. However, the problems of switching losses, current distortion around zero-crossing points, and neutral-point (NP) voltage fluctuation are mutually coupled for the Vienna rectifier. Therefore, this article proposes a modified carrier-based

The presence of unbalanced loads in power systems creates voltage imbalances that perturb the operation of sensitive equipment like induction motors, power electronics converters, and adjustable speed drives. To address this issue, this article presents a novel control scheme to perform remote negative-sequence voltage fair compensation at any node of a grid-forming inverter-based islanded ac microgrid

This article proposes a push–pull class- $\Phi _{2}$ inverter with a single three-winding integrated inductor. A design methodology is presented to achieve load-independent operation of the proposed class $\Phi _{2}$ inverter, ensuring consistent soft-switching operation and constant voltage gain under varying load conditions. A compact magnetic structure is proposed to implement the three-winding

This article proposes an adaptive-output-voltage-regulation (AOVR)-based solution to alleviate the dc-link undervoltage for grid-forming (GFM) inverters. First, it is shown that large disturbances may cause the dc-link undervoltage for GFM inverters threatening the safe operation of the system. To tackle this issue, an AOVR-based control strategy is proposed, whose main idea is to reduce the output

This article proposes a complementary-coupling compact receiver (RX) solution for an series–inductor–capacitor–capacitor-compensated wireless power transfer (WPT) system to tolerate the misalignment. To this end, a RX coil formed by four series L-shaped coils is proposed and integrated into the compensation (CX) coil. As a result, the mutual inductances (MIs) between the RX and transmitter (TX) coils

Recently, wireless power transfer (WPT) has been a competitive power supply mode due to its convenience and safety. Normally, a WPT system provides only one output, whereas some devices request multiple voltage levels. In this letter, a single-input and multioutput WPT system is proposed. By integrating two buck converters into a full-wave rectifier, three constant voltage outputs are achieved with

Simultaneous power and data transmission is possible by data injection into control signals of power converters without additional hardware. In this letter, a modified analog hysteretic current control is discussed, which combines data transmission with efficient quasi-square-wave zero-voltage switching. A half-bridge GaN converter with 99.1% efficiency is investigated with respect to power conversion

In this article, a robust wireless power transfer system is proposed with self-alignment capability and controllable output current characteristics for static charging of automatic-guided vehicles (AGVs). A reconfigurable circuitry is designed to work initially in an inductor–capacitor–capacitor-series compensation mode for achieving magnetic field self-alignment, then switched to the LCC – LCC configuration

In inductive power transfer systems, some applications require working at higher power levels, transferring power with longer air gaps, and meeting geometric constraints. Many situations will decrease system coupling and affect performance. In this article, a three-coil configuration based on an all-detuned design is proposed to optimize the overall coupling and system efficiency. Primary and tertiary

In this article, two transmitter-side model predictive control (MPC), namely, a model predictive-based phase shift control (MPPC) and a model predictive-based frequency control (MPFC), are proposed for direct inductive power transfer (IPT) systems. Both MPC strategies are empirically verified to have better dynamic responses than the proportional-integral (PI)-based counterparts using inexpensive digital

The three-phase four-leg (3P4L) voltage source inverter (VSI) with LC output filter is a suitable transformer-less topology to feed nonlinear and unbalanced loads in four-wire applications. Both symmetrical and asymmetrical short circuits can occur on the load-side. Moreover, due to the low thermal inertia of semiconductors, fast short-circuit protections are necessary to avoid damage by overheating

This article proposes a solution for driving a microdisplacement device in the coupling space of a wireless power transfer system. The solution involves using a levitation device made of a combination of Fe-based nanocrystalline alloys (Fe-NCS) and aluminium. The dynamic model of the levitation device is analyzed to understand the electromagnetic force involved, and an optimized grid-type Fe-NCS structure

In order to improve the efficiency, interior permanent magnet synchronous motors (IPMSMs) or the synchronous reluctance motors (SynRMs) need to be calibrated to obtain the maximum torque per ampere (MTPA) and flux-weakening (FW) curves. In industrial application, there are different types of IPMSMs and SynRMs. It is expensive and time-consuming to build test benches to calibrate each motor. In this

Time-delay is an inevitable operator causing slow dynamic response of related systems employing harmonic sequence (HS) filters/extractors. This letter presents a new concept of flexible time-delay designs as a further generalization of two-sample methods (i.e., delayed signal cancellation) to improve the dynamic response and robustness of HS filters/extractors. The new concept offers flexible designs

A resonant four-switch inverting buck–boost converter is a good choice for dc/dc applications that require an inverting voltage solution. A soft-switching control scheme with four segments of resonance current has been examined using duty ratio and phase shift as control variables. As a result, the rms value of the resonance current is low compared with discontinues current mode (DCM), which is directly

To address the special challenges for drone wireless in-flight charging systems, namely the continuous fluctuation of mutual inductance, large charging distance, and limited payload of the pickup, a novel high-order primary-series (S) and secondary-single-inductor-double-capacitor (SLDC) topology for parity-time (PT) symmetric wireless power transfer (WPT) system is proposed in this article. The reduced-order

The modular multilevel resonant dc–dc converters (MMRDCs) are becoming one of the most attractive candidates in medium voltage applications, but they would usually face technical challenges in high-efficient operation with wide input range and wide load condition. First, this article provides an elaborate review of the voltage control dimensions in MMRDC, and their corresponding operation principles

The symmetry principle has been widely used to mitigate the power stage common-mode (CM) emissions. Based on a symmetrical three-level (3-L) buck-boost converter in [1], this letter finds a midpoints interconnection that can reduce the CM noise further and realized the dc-link voltage auto-balance at the same time. By bridging the input and output midpoints, the noise is trapped inside the power converter

Due to its outstanding merits, such as quick response, multiobjective optimization, and simple principle, model predictive control (MPC) has been widely used in power converters and motor-drive systems. However, MPC highly relies on the precise circuit parameters and control models, and cannot be used in unknown circuit relationships. To solve this issue, this article presents a model-free predictive

The purpose of this letter is to present a simple technique for monitoring the health status of the output capacitor of a boost converter. The majority of previous studies have measured an electrolytic capacitor equivalent series resistance or capacitance to track its health condition. However, this letter suggests a new approach based on the accurate measurement of the dissipation factor. The effectiveness

Although the torque and radial force ripples are two important causes of unwelcomed vibration in switched reluctance machines, the suppression of these ripples is usually contradictory. To address this issue, we propose a model predictive torque and force control (MPT&FC) method. First, the torque and force sharing functions are constructed based on the flux-linkage curve, following which the sharing

A silicon carbide junction field effect transistors (SiC-JFETs) /gallium-nitride high electron mobility transistor (GaN-HEMT) hybrid power switch is proposed with scaled-up current rating enabled by parallel-connected high-voltage (HV, i.e., 1200 V) SiC-JFETs controlled by a single low-voltage enhanced-mode GaN-HEMT in a cascode configuration. Only one set of gate driver (for the GaN HEMT) is required

By incorporating an integrated low-voltage full bridge Cao et al., the concept of an electronic-embedded transformer (EET) offers a straightforward means of achieving high-frequency, high-power fixed-gain isolated dc–dc conversion, known as a dc transformer (DCX), through parallel operation of EET units with natural current sharing. However, EET-DCX, characterized by triangular transformer current

Multisampling is a very effective and direct way to reduce control delay, which can greatly improve the bandwidth and stability margin. However, it will introduce high-frequency switching harmonics (SHs), resulting in low-frequency aliasing in regular sampling puslewidth modulation (PWM). The harmonic suppression of existing filters inevitably brings phase lag, which weakens the advantage of multisampling

By applying rotor angle sensorless control methods, the costs of the electrical drive can be decreased while its reliability is increased. Traditionally, the design of both the rotor angle estimator and the drive controller require a detailed motor model and manual tuning leading to significant effort by human experts. In this article, a rotor anisotropy-based sensorless control scheme for interior

AC/DC power converter is the momentous interface of the power router, which is responsible for maintaining the dc bus voltage stability. However, under unbalanced and distorted grid voltage conditions, there are voltage ripples in the dc bus, and grid currents will also be severely distorted. Accordingly, this article proposes an improved passivity-based direct power control (IPBDPC) strategy based

The large-size and high-voltage reverse blocking integrated gate-commutated thyristor (RB-IGCT) is available for the hybrid line-commutated converter topology to effectively reduce the commutation failure probability. However, an abnormal turn -on phenomenon is observed in the fabricated 8-kV RB-IGCT samples, which potentially hinders the normal current switching and has not been investigated yet.

This letter proposes an inductive power transfer system to maintain stable output power in an ultrawide coupling variation range. Taking the series–series compensation as an example, the theoretical limit of detuned compensation is studied by defining two general impedance factors. Based on the circuit transformation, various detuned compensations can be studied in a unified manner, and then used to

To lower the circuit complexity and required space, and to prolong the lifetime of the hybrid energy storage system, a Z-source inverter (ZSI) topology is a suitable substitute for the traditional two-stage ones and has drawn attention in fuel cell (FC) hybrid electric vehicles (HEVs). This replacement requires a suitable selection of passive components for the Z-source network (ZSN) and a strict control

Buck converters are widely used in wireless power receiver systems for voltage conversion, impedance matching, and power regulation. However, when the receiver's resonant network has a current-source nature, it introduces a right-half-plane zero in the control-to-output transfer function, which adversely affects the system's transient performance. This article presents a proposed solution by reducing

Modular multilevel converters are well known in the energy sector. Generally, their stable operation is at the expense of numerous sensors, communication burden, and computationally expensive balancing strategies that challenge their expansion to cost-driven applications. Hence, introducing a sensorless voltage-balancing strategy with a simple controller is an attractive objective. Diode-clamped modular

Solid-state transformer (SST) based on Vienna cell features with less semiconductor devices and high-power density, providing a promising concept for super charging stations and uninterruptible power supply for data centers. However, the presence of numerous switching devices in SSTs raises the possibility of faults. Bypassing faulty cells not only adds to the cost by requiring additional bypass switches

Power converters with multiobjective functionality have ample scope of research in the power electronics field. As a consequence, a bidirectional multilevel buck rectifier (BMBR) is proposed for power factor correction applications. Unlike the existing bidirectional multilevel rectifiers, the proposed BMBR has excellent load scalability and stability. In addition, the proposed BMBR synthesizes multilevel

Hybrid and resonant switched-capacitor converters show promise in a number of power management applications, but are subject to a range of challenges in control and implementation. In particular, hybrid topologies use a network of switched flying capacitors to reduce voltage stress on switching devices and energy storage requirements of inductor(s). However, the increased order of system dynamics can

Literature reviews affirm the constructive influence of the intelligent predictive multiobjective control (IPMOC) on the power quality, power ancillary services, efficiency, and reliability expected from grid-tied transformerless multilevel converters. Regarding, this article contributes to developing the IPMOC concept in terms of training, autonomous power management, and real-time harmonic mitigation

This article proposed a partial power processing switched-capacitor converter (P 3 SCC) for medium voltage dc applications, where a high-frequency switched-capacitor converter (HFSCC) operating in a series resonant state is used to transmit most of the power, and the remaining small power is regulated by a partial power processing phase-shift full bridge (P 4 SFB). Different from the conventional switched

Multiphysics simulation software is indispensable for silicon carbide (SiC) power module design. Lacking interface between circuit simulation software and thermal-fluid-mechanical simulation software poses challenges for accurate design of the power modules. In this article, an automated field-circuit coupling simulation method based on the self-developed COMSOL-PSpice interface software is proposed

Existing quadrilateral-current-based zero voltage switching (ZVS) control methods of cascaded buck + boost converters (CBBCs) rely on instantaneous inductor current detection, posing a demanding requirement on the bandwidth of current sensors in high-frequency applications with hundreds of kilohertz. Also, with power level increasing, such methods become more sensitive to switching noise. To overcome

This article proposes a state plane feedforward (SPF) control to improve the dynamic response performance of LLC converters. In contrast to the traditional state-plane-based control, the proposed SPF control aims at the steady state analysis of state plane. The proposed SPF control predicts the switching period under specific operating conditions through state plane analysis with geometric simplification

A control strategy for the active power decoupling in a single-phase full-bridge-based bidirectional dc–ac converter is proposed in this work. An ac-side auxiliary-circuit three-leg topology is used for the implementation. The proposal makes use of the instantaneous power theory for three-phase systems, applied to single-phase systems. A closed-loop control in the power domain is implemented, by matching

This article presents a compact inductive power transfer (IPT) based wireless energy pick-up system (WEPUS) coupled gate-drive for medium-voltage power devices in modular direct current (dc) solid-state circuit breakers (SSCBs). There are two major contributions. First, an LCL-S compensated IPT system with constant voltage outputs is applied as auxiliary power supply to power ten submodules in SSCBs