IEEE Journal of Emerging and Selected Topics in Power Electronics

Wireless power transfer (WPT) using magnetic resonance is the technology which could set human free from the annoying wires. In fact, the WPT adopts the same basic theory which has already been developed for at least 30 years with the term inductive power transfer. WPT technology is developing rapidly in recent years. At kilowatts power level, the transfer distance increases from several millimete... View full abstract»

Wind power is still the most promising renewable energy in the year of 2013. The wind turbine system (WTS) started with a few tens of kilowatt power in the 1980s. Now, multimegawatt wind turbines are widely installed even up to 6-8 MW. There is a widespread use of wind turbines in the distribution networks and more and more wind power stations, acting as power plants, are connected directly to the... View full abstract»

The solid-state transformer (SST), which has been regarded as one of the 10 most emerging technologies by Massachusetts Institute of Technology (MIT) Technology Review in 2010, has gained increasing importance in the future power distribution system. This paper presents a systematical technology review essential for the development and application of SST in the distribution system. The state-of-th... View full abstract»

Inductive power transfer (IPT) has progressed to be a power distribution system offering significant benefits in modern automation systems and particularly so in stringent environments. Here, the same technology may be used in very dirty environments and in a clean room manufacture. This paper reviews the development of simple factory automation (FA) IPT systems for both today's complex applicatio... View full abstract»

In order to reduce size and cost, high-order passive filters are generally preferred in power converters to cancel out high-frequency harmonics caused by pulsewidth modulation. However, the filter resonance peaks may require the use of passive dampers to stabilize the interactions between the load and source impedances. Furthermore, the stabilizing effect is more difficult to be guaranteed for cos... View full abstract»

Operational controls are designed to support the integration of wind and solar power within microgrids. An aggregated model of renewable wind and solar power generation forecast is proposed to support the quantification of the operational reserve for day-ahead and real-time scheduling. Then, a droop control for power electronic converters connected to battery storage is developed and tested. Compa... View full abstract»

The microgrid concept is gaining popularity with the proliferation of distributed generation. Control techniques in the microgrid are an evolving research topic in the area of microgrids. A large volume of survey articles focuses on the control techniques of the microgrid; however, a systematic survey of the hierarchical control techniques based on different microgrid architectures is addressed ve... View full abstract»

This paper demonstrates that the sum and difference of the upper and lower arm voltages are suitable variables for deriving a generalized state-space model of a modular multilevel converter (MMC) which settles at a constant equilibrium in steady-state operation. The presented modeling approach separates the multiple frequency components appearing within the MMC as a first step of the model derivat... View full abstract»

The virtual synchronous generator (VSG) is a control scheme applied to the inverter of a distributed generating unit to support power system stability by imitating the behavior of a synchronous machine. The VSG design of our research incorporates the swing equation of a synchronous machine to express a virtual inertia property. Unlike a real synchronous machine, the parameters of the swing equatio... View full abstract»

Power electronics has progressively gained an important status in power generation, distribution, and consumption. With more than 70% of electricity processed through power electronics, recent research endeavors to improve the reliability of power electronic systems to comply with more stringent constraints on cost, safety, and availability in various applications. This paper serves to give an ove... View full abstract»

Various noncontacting methods of plug-in electric vehicle charging are either under development or now deployed as aftermarket options in the light-duty automotive market. Wireless power transfer (WPT) is now the accepted term for wireless charging and is used synonymously for inductive power transfer and magnetic resonance coupling. WPT technology is in its infancy; standardization is lacking, es... View full abstract»

Conventional wireless chargers typically utilize a traditional architecture in the receiver to convert RF signals to dc power, which includes rectification of the resonant current, a dc-dc conversion, and finally a battery charging stage by either a linear or switching regulator. Such implementation requires multiple stages and associated components, while in many new applications, both size and e... View full abstract»

This paper performs an extensive review on control schemes and architectures applied to dc microgrids (MGs). It covers multilayer hierarchical control schemes, coordinated control strategies, plug-and-play operations, stability and active damping aspects, as well as nonlinear control algorithms. Islanding detection, protection, and MG clusters control are also briefly summarized. All the mentioned... View full abstract»

The light-load efficiency has drawn more and more attention for the LLC resonant converters in information technology industry. Burst mode is an effective and popular method to improve the light-load efficiency. The conventional burst mode control has limited efficiency improvement on LLC converter due to the dynamics of the resonant tank. The simplified optimal trajectory control (SOTC) for burst... View full abstract»

Gallium nitride (GaN) power devices are an emerging technology that have only recently become available commercially. This new technology enables the design of converters at higher frequencies and efficiencies than those achievable with conventional Si devices. This paper reviews the characteristics and commercial status of both vertical and lateral GaN power devices, providing the background nece... View full abstract»

For three-phase LCL-type grid-connected converter, when it is attached to weak grid, current control interacts with phase-locked loop (PLL) via point of common coupling voltage. Consequently, PLL dynamic might deteriorate grid current control and even result in system instability. However, the conventional design method of current controller neglects the impact of PLL, and therefore, it is hard fo... View full abstract»

Roadway-powered electric vehicles (RPEVs) are attractive candidates for future transportation because they do not rely on large and heavy batteries but directly and efficiently get power while moving along a road. The inductive power transfer systems (IPTSs) that have been widely used for the wireless powering of RPEVs are reviewed in this paper. The development history of the IPTS is tracked from... View full abstract»

In an islanding microgrid with meshed structure, accurate reactive power sharing is more difficult than in a traditional single-bus microgrid due to its complex inner structure. This paper proposes an enhanced power-sharing control scheme designed to share both active and reactive power accurately in a meshed microgrid, with the aid of adaptive regulation of the virtual impedances. The proposed co... View full abstract»

In this paper, a detailed analysis that yields in-depth insight into the design of an undersea wireless power transfer (UWPT) system is presented. Based on the analytical results, a methodology for an optimized coil design to increase the power transfer efficiency is presented. Owing to the constant motion experienced by a UWPT system, a necessary feature is the ability to operate at a multitude o... View full abstract»

This paper presents a single-phase differential buck-boost inverter that possesses both buck-boost and active power decoupling functions without adding any power electronics or increasing the complexity of driver circuits as compared with previous differential inverters. Two types of operating principles of the differential buck-boost inverter are introduced: the unipolar operation with new pulse ... View full abstract»

This paper proposes an improved finite set model predictive control (FS-MPC) to reduce current ripples and balance the neutral-point voltage for grid connected three level voltage source inverter. The proposed finite set model predictive current control (FS-MPCC) is based on the discrete space vector modulation (DSVM) to synthesize various voltage vectors. The proposed DSVM method enables to calcu... View full abstract»

In this paper, a three-phase grid-connected photovoltaic (PV) topology (named H8) is proposed to address the leakage current issue. AC common-mode voltage and earth leakage current cause problems in the transformerless grid-connected PV systems. Leakage current increases the distortion of the current injected into the grid and the losses, also it generates unwanted radiated and conducted electroma... View full abstract»

As already happens with the electric vehicles (EVs) expansion, technology associated with their charge also must be improved. This paper presents a novel decentralized control method (DCM) for charging stations (CSs) based on a medium-voltage direct current (MVDC) bus. This kind of CSs is integrated in a microgrid with a photovoltaic system, a battery energy storage system (ESS), a local grid conn... View full abstract»

Integrated magnetics is applied to replace the three-discrete transformers by a single core transformer in a three-phase LLC resonant converter. The magnetic circuit of the integrated transformer is analyzed to derive coupling factors between the phases; these coupling factors are intentionally minimized to realize the magnetic behavior of the three-discrete transformers, with the benefit of elimi... View full abstract»

In this paper, a new multi-phase interleaved dc/dc converter is presented. The proposed converter consists of two symmetric sections. Each section consists of several switches, inductors, diodes, and capacitors. In order to obtain high voltage gain, the proposed converter can be extended to n stages of voltage multiplier units which are used between the phases. Hence the voltage gain of the propos... View full abstract»

In this paper, the small signal stability issue of a dual-active-bridge (DAB) converter enabled dc microgrid is addressed. The derived impedance characteristic of the source DAB converter reveal that the stability of this dc grid is decided by the low-frequency terminal behaviors of integrated units, which is different from that of dc microgrids powered by other types of source converters. At this... View full abstract»

In this paper, the current status and the requirements of primary electric propulsion components-the battery, the electric motors, and the power electronics system-are reviewed. The future trends in the electric propulsion systems, battery charging, and the types of power trains are presented. Possible future electric vehicle powertrain systems based on lithium air battery and plug-in fuel cell ve... View full abstract»

Single-inductor multiple-output (SIMO) LED drivers have the advantages of being compact, efficient and low cost. However, the voltage-to-current transfer function of each output of the SIMO converter is not independent, with significant cross regulation issues that necessitate the use of complex closed-loop control for achieving independent dimming function. This paper proposes a current-source-mo... View full abstract»

Solid-state transformers (SSTs) are a promising technology as they provide new functionalities and services enabling future smart grids. An SST establishes the interface between an MV ac grid and an LV (ac or dc) grid or load. The SST must provide high reliability even in the event of certain grid faults, where the SST is subject to exceptional electrical stresses. In addition, the MV and LV grids... View full abstract»

Power-electronics-based medium-voltage direct current (MVDC) shipboard power systems consist of several interconnected feedback-controlled switching converters. Such systems suffer from stability degradation owing to the negative incremental resistance of the constant-power loads. To tackle the stability problem, system-level stabilizing control methods were proposed acting on either the load-side... View full abstract»

This paper focuses on the output parallel dual active bridge (DAB) dc-dc converters in power electronic traction transformers (PETT). A model predictive control with current-stress-optimized (MPC-CSO) scheme based on dual phase-shift (DPS) is proposed to improve the dynamic performance, balance the transmission power, and realize the current stress optimization. The dynamic behavior of output volt... View full abstract»

In this paper, we propose a direct power control (DPC) method for the AC/DC converter based on the designed dynamic nonlinear model and an approach on selecting the best possible switching state, aiming at guaranteeing the AC current quality and improving the transient performance, especially under the unbalanced power-source voltage conditions. The proposed DPC mainly consists of three parts, sec... View full abstract»

Resonant controllers (RSCs) are widely adopted for controlling power converters since they can track AC signals of both positive and negative sequences without steady-state error. However, the performance of RSCs has not been fully exploited due to the improper phase compensation angle and insufficient controller gain. In this paper, a novel controller parameters design method, which is based on t... View full abstract»

This paper reviews the trends in wind turbine generator systems. After discussing some important requirements and basic relations, it describes the currently used systems: the constant speed system with squirrel-cage induction generator, and the three variable speed systems with doubly fed induction generator (DFIG), with gearbox and fully rated converter, and direct drive (DD). Then, possible fut... View full abstract»

The interconnection stability of a grid-connected voltage-source converter (VSC) can be assessed by the passivity properties of the VSC input admittance. If critical grid resonances fall within regions where the input admittance acts passively, i.e., has nonnegative real part, then their destabilization is generally prevented. This paper presents an overview of passivity-based stability assessment... View full abstract»

Finite Set Model Predictive Control (FS-MPC) has many advantages, such as a fast dynamic response and an intuitive implementation. For these reasons, it has been thoroughly researched during the last decade. However, the wave form produced by FS-MPC has a switching component whose spread spectrum remains a major disadvantage of the strategy. This paper discusses a modulated model predictive contro... View full abstract»

SiC MOSFETs exhibit extremely fast switching characteristics, which are unfortunately accompanied by undesirable switching oscillations. In this paper, equivalent circuit models incorporating all parasitic elements are developed for the turn-ON and turn-OFF of a SiC MOSFET. Simple mathematical formulas are derived to provide the theoretical analysis of the switching oscillation phenomenon, and to ... View full abstract»

Variable speed Induction Motor drives with Predictive Torque Control (PTC) technique is an advancing technology nowadays. The PTC technique is introduced for dual inverter fed Open End Winding Induction Motor (OEWIM) configuration owing to its benefits. The conventional PTC requires flux weighting factor assignment because of two different control objectives (Torque and Flux) in single cost functi... View full abstract»

This paper presents a historical and philosophical perspective on a possible future for power electronics. Technologies have specific life cycles that are driven by internal innovation, subsequently reaching maturity. Power electronics appears to be a much more complex case, functioning as an enabling technology spanning an enormous range of power levels, functions and applications. Power electron... View full abstract»

This paper introduces a fully integrated 12-to-1.xV voltage regulator module IC. A fully synthesizable digital two-loop controller has been realized through hardware description language tools. Several new IP blocks have been developed and described in detail: a window delay-line-based analog to digital converter (DL-ADC), two independent PI compensators with shared hardware for calculations, high... View full abstract»

Field experience has shown that subsynchronous oscillation and harmonic resonance can occur between wind farms (WFs) and high voltage dc (HVdc) systems. The oscillations can appear in the presence of background harmonics due to the interaction between the wind energy conversion system's (WECS's) converter controller, HVdc converter controller, and the impact of the interconnection system impedance... View full abstract»

Voltage-source converters (VSCs) are widely used in renewable energy sources as the grid interface, e.g., wind turbine generators and photovoltaics. These VSCs control the dc-link capacitor voltage and the reactive power output to track the reference values, which generally apply phase-locked loop (PLL) for grid synchronization. However, the dynamic performance of the conventional PLL can be deter... View full abstract»

Photovoltaic (PV) thin-film modules normally present higher voltages at the maximum power points (MPPs) than crystalline silicon ones. This feature makes the usage of low voltage MOSFETs (≤100V) unfeasible in high step-up Boost-based converters. In order to solve this drawback, this paper proposes a novel high step-up non-isolated dc-dc converter based on the classical synchronous Buck conv... View full abstract»

The single-vector based model predictive based direct power control (MPDPC) is commonly used for control of three-phase full-bridge AC/DC converters, but it could only select the best vector to apply. Due to the limited number of voltage vectors, the sampling frequency needs to be high to achieve an acceptable performance. It also bears with variable switching frequency which causes spread spectru... View full abstract»

A design approach for grid-connected inverter controllers for distributed and renewable energy system applications is proposed, where a high number of controller gains can be designed optimally in a fairly systematic way. The linear quadratic regulator problem is first modified to accommodate sinusoidal signal tracking through a meaningful state-space transformation. The cost function is modified ... View full abstract»

Modular multilevel converter (MMC) is one of the most promising topologies for medium to high-voltage high-power applications. The main features of MMC are modularity, voltage and power scalability, fault tolerant and transformer-less operation, and high-quality output waveforms. Over the past few years, several research studies are conducted to address the technical challenges associated with the... View full abstract»

This paper proposes an output voltage regulation scheme for a fuel cell-based power source. The proposed methodology relies on the design of a dynamic backstepping average current-mode controller considering the combined fuel cell stack and boost converter model. Also, an external loop for voltage regulation using a proportional-integral action is added. Moreover, to improve the robustness of the ... View full abstract»

Representation of ac power systems by frequency-dependent impedance equivalents is an emerging technique in the dynamic analysis of power systems including power electronic converters. The technique has been applied for decades in dc-power systems, and it was recently adopted to map the impedances in ac systems. Most of the work on ac systems can be categorized into two approaches. One is the anal... View full abstract»

Voltage angle control not only can solve the problem that two current regulators of traditional algorithms conflict with each other, but also has the advantage of maximum utilization of the dc-link voltage. Based on the basic equations of permanent-magnet synchronous motors (PMSM) in id-iq coordinate plane, the principle of voltage angle control is analyzed and a single q-axis current regulator-va... View full abstract»

This paper presents a multiprocessor hardware-in-the-loop (HIL) fault injection strategy for real-time simulation of faults in traction control system (TCS). TCS models are solved for the implementation in CPU and field-programmable gate array. A timing optimization method based on static timing analysis is proposed to deal with timing error induced by real-time fault injection. A multiprocessor-b... View full abstract»