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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. Source


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. Source


Zhang Z.,Jiangsu Key Laboratory of New Energy Generation and Power Conversion | Xu P.,Bel Power Company | Liu Y.-F.,Queens 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. Source


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.,Queens 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. Source


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. Source

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