IEEE Journal of Emerging and Selected Topics in Power Electronics

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»

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»

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»

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»

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»

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»

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»

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»

This paper proposes a novel two-stage topology for a 6.6-kW on-board charger. The first stage, employing an interleaved bridgeless totem-pole ac/dc in critical conduction mode to realize zero-voltage switching, is operated at over 300 kHz. A bidirectional CLLC resonant converter operating at 500 kHz is chosen for the second stage. A variable dc-link voltage is adopted to track the wide battery vol... 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»

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»

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»

High-voltage direct current (HVDC) transmission systems based on modular multilevel converters (MMCs) are a promising solution for efficient bulk power transmission over long distances. As grid-connected converters, the occurrence of grid-side faults is rather common, leading to imbalances and distortions of the ac-side voltages. Therefore, operation and control of MMC-HVDC systems under grid imba... View full abstract»

Connected and automated hybrid electric vehicles (CAHEVs) have the potential to improve safety and mitigate traffic congestions. A crucial problem of the CAHEVs is that the Lithium-Ion batteries are highly temperature-sensitive. Therefore, a practical and energy-efficient battery thermal management (BTM) strategy is required with the minimum possible cooling/heating energy consumption. To achieve ... View full abstract»

The totem-pole bridgeless power factor correction (PFC) rectifier has recently been recognized as a promising front-end candidate for applications like servers and telecommunication power supplies. This paper begins with a discussion of the advantages of using emerging high-voltage gallium-nitride (GaN) devices in totem-pole PFC rectifiers rather than traditional PFC rectifiers. The critical-mode ... 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»

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»

In this paper, a control strategy for power flow management of a grid-connected hybrid photovoltaic (PV)-wind-battery-based system with an efficient multi-input transformer-coupled bidirectional dc-dc converter is presented. The proposed system aims to satisfy the load demand, manage the power flow from different sources, inject the surplus power into the grid, and charge the battery from the grid... 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»

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»

A new dc-dc converter with high voltage gain is proposed in this study. The proposed converter consists of two switches which are turned on and off simultaneously. Additionally, two Switched-Capacitor (SC) cells and one Energy Storage (ES) cell are utilized in the structure of the proposed converter. These result in high voltage gains at low values of the duty cycle. Besides, the voltage stress ac... 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»

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»

High-step-up, high-efficiency, and cost-effective dc-dc converters, serving as an interfacing cell to boost the low-voltage output of renewable sources to the utility voltage level, are an important part in renewable energy systems. Over the past few years, there has been a substantial amount of studies devoted to high-step-up dc-dc converters. Among them, the category of coupled-inductor boost co... View full abstract»

A new three-phase integrated onboard charger and derivative control strategy are proposed and implemented in this paper. The integrated charger is composed of a three-phase interface and the traction propulsion system of the vehicle. The three-phase interface is derived based on the traditional three-phase three-switch buck ac-dc converter and is integrated with the propulsion system to construct ... 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»

This paper presents a comparison between the performances of different interleaving control methods for gallium nitride devices-based MHz critical conduction mode (CRM) totem-pole power factor correction (PFC) circuit. Both closed-loop interleaving and open-loop interleaving are good for the 70-kHz CRM PFC; but for a MHz frequency CRM PFC with microcontroller (MCU) implementation, the open-loop in... 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»

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 this paper, a new single switch high step-up dc-dc converter with high voltage gain is proposed. The proposed topology is developed by combining boost and single-ended primary inductor converter with diode-capacitor circuit to reduce the stress across the semiconductor devices. The proposed converter produces low switching voltage and hence it improves its efficiency. The operating principle an... 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»

This paper presents a method for minimizing the cost of vehicle battery charging given variable electricity costs while also accounting for estimated costs of battery degradation using a simplified lithium-ion battery lifetime model. The simple battery lifetime model, also developed and presented here, estimates both energy capacity fade and power fade and includes effects due to temperature, stat... View full abstract»

This paper details the optimization of inductive power transfer (IPT) coil systems with respect to efficiency η and area-related power density α as required in electric vehicle applications. Based on analytical calculations and finite-element models, which are discussed and experimentally verified in detail, generally valid design guidelines for high-power IPT systems are derived, and the η-α-Pare... View full abstract»

On-chip power supply distribution faces the challenges of high and fast-changing load current, limited metal layers and decoupling capacitors, efficiency, and thermal issues. This paper mainly discusses system-level design considerations of both distributed and centralized fully integrated voltage regulators. In particular, a ring-shaped switched-capacitor dc-dc converter that has a unity-gain fre... View full abstract»

In order to optimize the solar photovoltaic (PV) generated power using a maximum power point tracking technique, a dc-dc conversion stage is usually required in solar PV fed water pumping which is driven by a brushless dc (BLDC) motor. This power conversion stage leads to an increased cost, size, complexity, and reduced efficiency. As a unique solution, this paper addresses a single stage solar PV... View full abstract»

In this paper, a small-signal model of voltage source converter (VSC) is developed to investigate the stability of dc-link voltage control. This model contributes to representing the dc-link voltage dynamics characteristics of VSC integrated to weak grid. Effects of grid strength, operating point, and control loops' interactions on the performance of VSC are taken into consideration. Based on the ... View full abstract»

This paper presents DC fault analysis for a dual active bridge DC/DC converter which comprises of two active bridges and an internal medium frequency transformer. This topology provides galvanic isolation, voltage step up/down and bidirectional power transfer. The DC fault study assumes the DC terminal voltage of the converter is at zero. The steady state fault current is limited to a low magnitud... 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»

In this paper, power electronic transformer (PET)-based railway traction systems are comprehensively reviewed according to the unique application features and requirements. By comparing PET and conventional line frequency transformer (LFT)-based systems, their pros and cons are summarized. By further reviewing all kinds of PET-based designs from the early concepts to the latest ones in the order o... 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»

Within a solid-state transformer, the isolated dc-dc converter and in particular its medium-frequency transformer are one of the critical components, as it provides the required isolation between primary and secondary sides and the voltage conversion typically necessary for the operation of the system. A comprehensive optimization procedure is required to find a transformer design that maximizes p... 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»

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 the IGBT-based bidirectional isolated dual-active-bridge (DAB) dc-dc converter, it is not necessary that the IGBTs of the secondary-side H-bridge inverter (HB2) retain under on state because in this system, the function of synchronous rectification cannot be realized. This paper firstly analyzes the characteristics of the DAB converter with all of the IGBTs of HB2 keeping under OFF state. Its m... View full abstract»

A novel fast and reliable open circuit fault diagnosis strategy for a Matrix Converter with a Finite Control Set Model Predictive Control strategy is proposed in this paper. Current sensors are located ahead of the clamp circuit to measure the output currents in order to improve the speed of fault diagnosis. In addition, the current recirculating path during a single open circuit switch fault cond... View full abstract»

Two-stage photovoltaic (PV) configurations have become increasingly popular due to the decoupling between the inverter dc-link voltage and the PV voltage, adding flexibility to extend the MPPT range. However, the additional dc-dc converter increases the power converter losses. The concept of partial power converters (PPC), which reduce the amount of power handled by the dc-stage can mitigate this ... View full abstract»

Data centers demand high-current, high-efficiency, and low-cost power solutions. The high-voltage dc distribution power architecture has been drawing attention due to its lower conduction loss on cables and harnesses. In this structure, the 380-12 V high output current isolated converter is the key stage. This paper presents a 1-MHz 1-kW LLC resonant converter using GaN devices and planar matrix t... 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»