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Chen Z.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | Chen R.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | Chen Z.,University of Aalborg
IEEE Transactions on Industrial Electronics | Year: 2013

The fault-tolerance design is widely adopted for high-reliability applications. In this paper, a parallel structure of single-phase full-bridge rectifiers (FBRs) (PS-SPFBR) is proposed for a wound-field doubly salient generator. The analysis shows the potential fault-tolerance capability of the PS-SPFBR over the common three-phase FBR. The normal no-load and loading operations are discussed, and the fault-tolerance ability is analyzed. A doubly salient generator prototype is built and tested; the machine is also modeled and simulated with the finite element method. The results obtained from simulation are in good agreement with that from the experiments under both normal no-load and loading operations. The impacts of a single-phase open-circuit fault have been discussed, and the fault-tolerance ability has been demonstrated. © 1982-2012 IEEE.


Yao Z.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | Yao Z.,Yancheng Institute of Technology | Xiao L.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion
IEEE Transactions on Power Electronics | Year: 2012

Renewable energy sources, such as solar energy and fuel cells, are desirable due to their pollution-free properties. In order to utilize the present infrastructure of the utility grid for power transmission and distribution, grid-connected inverters are required for distributed generation systems, which should have high reliability. However, a shoot-through problem, which is a major deterrent to the reliability of the inverters, exists in the conventional bridge-type voltage-source inverters. In order to solve the aforementioned problem, this paper proposes a two-switch dual-buck grid-connected inverter. The freewheeling current flows through the independent diodes instead of the body diodes of the switches, so reverse-recovery loss of the diodes can be reduced. Half of the power devices operate in high frequency; the others switch at grid period with zero-current switching. Moreover, uniploar modulation is used. The operating principle, design guidelines and example, and stability analysis are provided. The proposed inverter can be simplified to a current amplifier with hysteresis current control, so it is globally stable. Simulation and experimental results verify the theoretical analysis and satisfy IEEE Std. 929-2000. A comparison of a full-bridge inverter and the proposed inverter shows that the proposed inverter is more attractive in high-reliability applications. © 1986-2012 IEEE.


Wu H.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | Sun K.,Tsinghua University | Ding S.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | Xing Y.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion
IEEE Transactions on Power Electronics | Year: 2013

A systematic approach is proposed for the derivation of nonisolated three-port converter (TPC) topologies based on dual-input converters (DIC) and dual-output converters (DOC), which serves as an interface for a renewable source, a storage battery, and a load simultaneously. The power flow in a TPC is analyzed and compared with that in a DIC or a DOC, respectively. Beginning with building the power flow paths of a TPC from a DIC or a DOC, the general principles and detailed procedures for the generation and optimization of TPC topologies are presented. Based on these works, a family of nonisolated TPC topologies is developed. The derived TPCs feature single-stage power conversion between any two of the three ports, and result in high integration and high efficiency. One of the proposed TPCs, named Boost-TPC, is taken as an example for verifying the performance of its circuit topology with related operational methods. Pulsewidth modulation and power management methods, used in this circuit, are analyzed in detail. Experiments have been carried out on a 1-kW prototype of the Boost-TPC, which demonstrate the feasibility and effectiveness of the proposed topology derivation method. © 2012 IEEE.


Hu H.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | Harb S.,Texas A&M University | Kutkut N.,University of Central Florida | Batarseh I.,University of Central Florida | Shen Z.J.,University of Central Florida
IEEE Transactions on Power Electronics | Year: 2013

Thereliability of the microinverter is a very important feature that will determine the reliability of the ac-module photovoltaic (PV) system. Recently, many topologies and techniques have been proposed to improve its reliability. This paper presents a thorough study for different power decoupling techniques in singlephase microinverters for grid-tie PV applications. These power decoupling techniques are categorized into three groups in terms of the decoupling capacitor locations: 1) PV-side decoupling; 2) dc-link decoupling; and 3) ac-side decoupling. Various techniques and topologies are presented, compared, and scrutinized in scope of the size of decoupling capacitor, efficiency, and control complexity. Also, a systematic performance comparison is presented for potential power decoupling topologies and techniques. © 2013 IEEE.


Hu X.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | Hu X.,Anhui University of Technology | Gong C.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion
IEEE Transactions on Power Electronics | Year: 2014

High voltage gain dc-dc converters are required in many industrial applications such as photovoltaic and fuel cell energy systems, high-intensity discharge lamp (HID), dc back-up energy systems, and electric vehicles. This paper presents a novel input-parallel output-series boost converter with dual coupled inductors and a voltage multiplier module. On the one hand, the primary windings of two coupled inductors are connected in parallel to share the input current and reduce the current ripple at the input. On the other hand, the proposed converter inherits the merits of interleaved series-connected output capacitors for high voltage gain, low output voltage ripple, and low switch voltage stress. Moreover, the secondary sides of two coupled inductors are connected in series to a regenerative capacitor by a diode for extending the voltage gain and balancing the primary-parallel currents. In addition, the active switches are turned on at zero current and the reverse recovery problem of diodes is alleviated by reasonable leakage inductances of the coupled inductors. Besides, the energy of leakage inductances can be recycled. A prototype circuit rated 500-W output power is implemented in the laboratory, and the experimental results shows satisfactory agreement with the theoretical analysis. © 1986-2012 IEEE.


Chen Z.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | Liu S.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | Shi L.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion
IEEE Transactions on Power Electronics | Year: 2014

A phase-shift zero voltage switching (ZVS) pulse width modulation full-bridge converter with reduced parasitic oscillation across the rectifier is proposed. The introduced auxiliary transformer used as a voltage source forces the primary current commutating in advance. Parasitic voltage oscillation at secondary is well reduced and there is no duty cycle loss. ZVS of primary switches can be achieved in much wide load range with the help of an auxiliary coupled inductor, and the main transformer continuously transfers energy to load in a whole switching cycle, resulting in no circulating time, and ripple current flowing through the output filter inductor decreases significantly. In this paper, operation principle of the circuit is analyzed in detail. Besides, discussion of key characteristics and design considerations are also included. Finally, experimental results from a 480-W/48-V, 100-kHz prototype are presented to confirm the superior features of the proposed converter. © 1986-2012 IEEE.


Zhang Z.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | Xu P.,Bel Power Corporation | Liu Y.-F.,Queen's University
IEEE Transactions on Power Electronics | Year: 2013

Recently, current source drivers (CSDs) have been proposed to reduce the switching loss and gate drive loss in megahertz (MHz) dc-dc converters, in which the duty cycle normally has a steady-state value. However, different from dc-dc converters, the duty cycle of the power factor correction (PFC) converters is modulated fast and has a wide operation range during a half-line period in ac-dc applications. In this paper, an adaptive full-bridge CSD is proposed for the boost PFC converters. The proposed CSD can build adaptive drive current inherently depending on the drain current of the main power MOSFET. Compared to the CSDs with the constant drive current, the advantage of the adaptive drive current is able to reduce the switching loss further when the MOSFET is with a higher switching current, while minimize the drive circuit loss when the MOSFET is with a lower switching current. Therefore, the adaptive CSD is able to realize better design tradeoff between the switching loss and drive circuit loss so that the efficiency can be optimized in a wide operation range. Furthermore, no additional auxiliary circuit and control are needed to realize the adaptive current by the proposed CSD. The experimental results verified the functionality and advantages. For a 1-MHz/300-W boost PFC converter, the proposed CSD improves the efficiency from 89 using a conventional voltage driver to 92.2 (an improvement of 3.2) with 110V $\bf ac input, 380V output, and full-load condition. © 1986-2012 IEEE.


Zhang Z.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | He X.-F.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | Liu Y.-F.,Queen's University
IEEE Transactions on Power Electronics | Year: 2013

Boundary conduction mode (BCM) and discontinuous conduction mode (DCM) control strategies are widely used for the flyback microinverter. The BCM and DCM control strategies are investigated for the interleaved flyback microinverter concentrating on the loss analysis under different load conditions. These two control strategies have different impact on the loss distribution and thus the efficiency of the flyback microinverter. For the interleaved flyback microinverter, the dominant losses with heavy load include the conduction loss of the power MOSFETs and diodes, and the loss of the transformer; while the dominant losses with light load include the gate driving loss, the turn-off loss of the power MOSFETs and the transformer core loss. Based on the loss analysis, a new hybrid control strategy combing the two-phase DCM and one-phase DCM control is proposed to improve the efficiency in wide load range by reducing the dominant losses depending on the load current. The optimal design method based on the boundary condition of the hybrid control is also presented. The experimental results verify the benefits of the proposed control. © 1986-2012 IEEE.


Zhang Z.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | Tao Y.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | Yan Y.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion
IEEE Transactions on Industrial Electronics | Year: 2012

This paper proposes and implements a new topology of hybrid excitation doubly salient brushless dc generator (HEDS-BLDCG). Configuration and flux control principle of the generator are presented. Two-dimensional finite-element methods are used to investigate the static field distribution characteristics of this new type of generator. Field-circuit coupled analysis is successfully performed, and the output characteristics of different windings are obtained. A prototype HEDS-BLDCG is designed and developed, and the experimentation is also given to verify the validity of the proposed brushless dc generator with one and dual terminal outputs. The results confirm the excellent field-regulation capability of HEDS-BLDCG, and the rectified output of the permanent-magnet part can serve as the independent power of the excitation winding when the HEDS-BLDCG has two sets of output windings. © 2011 IEEE.


Tang Y.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | Xie S.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | Ding J.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion
IEEE Transactions on Industrial Electronics | Year: 2014

This paper proposes the pulsewidth modulation (PWM) strategy of Z-source inverters (ZSIs) with minimum inductor current ripple. In existing PWM strategy with single-phase shoot-through, the shoot-through time interval is divided into six equal parts, therefore the three phase legs bear the equal shoot-through time interval. In this manner, the allotment and arrangement of the shoot-through state is easy to realize, but the inductor current ripple is not optimized. This causes to use relatively large inductors. In the proposed PWM strategy, the shoot-through time intervals of three phase legs are calculated and rearranged according to the active state and zero state time intervals to achieve the minimum current ripple across the Z-source inductor, while maintaining the same total shoot-through time interval. The principle of the proposed PWM strategy is analyzed in detail, and the comparison of current ripple under the traditional and proposed PWM strategy is given. Simulation and experimental results on the series ZSI are shown to verify the analysis. © 1982-2012 IEEE.

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