ZVS Resonant Converter With Parallel–Series Transformer Connection
ABSTRACT A new series resonant converter with a parallel-series transformer connection is proposed in order to achieve zero voltage switching (ZVS) for all power switching, zero current switching (ZCS) for rectifier diodes at a full load, and less transformer secondary winding with a full-wave rectifier. For high-output-voltage applications, the primary windings of two transformers are connected in parallel in order to share the input current and reduce the root-mean-square rms current on the primary windings such that the copper losses on the transformers are reduced. The secondary windings of the two transformers are connected in series in order to ensure that the primary side currents are balanced and the secondary winding turns are also reduced. Thus, the sizes of the transformer core and bobbin are reduced. The full-wave diode rectifier is used on the output side. Thus, the voltage stress of the rectifier diode is equal to the output voltage rather than being two times the output voltage as that in a center-tapped rectifier topology. Based on the resonant behavior, all switches are turned on at the ZVS, and the rectifier diodes are turned off at the ZCS if the operating switching frequency is less than the series resonant frequency. The laboratory experiments with a 660-W prototype, verifying the effectiveness of the proposed converter, are described.
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ABSTRACT: This paper studies a new three-level pulse-width modulation (PWM) resonant converter for high input voltage and high load current applications. In order to use high frequency power MOSFETs for high input voltage applications, a three-level DC converter with two clamped diodes and a flying capacitor is adopted in the proposed circuit. For high load current applications, the secondary sides of the proposed converter are connected in parallel to reduce the size of the magnetic core and copper windings and to decrease the current rating of the rectifier diodes. In order to share the load current and reduce the switch counts, three resonant converters with the same active switches are adopted in the proposed circuit. Two transformers with a series connection in the primary side and a parallel connection in the secondary side are adopted in each converter to balance the secondary side currents. To overcome the drawback of a wide range of switching frequencies in conventional series resonant converters, the duty cycle control is adopted in the proposed circuit to achieve zero current switching (ZCS) turn-off for the rectifier diodes and zero voltage switching (ZVS) turn-on for the active switches. Finally, experimental results are provided to verify the effectiveness of the proposed converter.Journal of power electronics 01/2014; 14(1). · 0.78 Impact Factor
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ABSTRACT: A Soft-Switching DC-DC Converter with low voltage and current stresses on switches and high voltage gain is proposed in this paper. The voltage and current stresses of switches are considerably reduced. As a result a reduction of switching losses in turn ON and OFF states of switching is obtained. Also, using soft-switching method results lower losses. In the result of ZCS in output diodes, reverse recovery problem of diodes is alleviated. Because of total reduction of losses, efficiency is improved. The proposed converter is a quasi-resonant converter controlled by pulse width modulation (PWM) method.Power Electronics, Drive Systems and Technologies Conference (PEDSTC), 2013 4th; 01/2013
Conference Paper: Analysis of a new soft switching converter with three resonant tanks[Show abstract] [Hide abstract]
ABSTRACT: This paper presents a new zero-voltage switching (ZVS) DC/DC converter with three resonant tanks for high input voltage and high load current applications. Two series half-bridge legs and two split capacitors in order to limit the voltage stress of active switches at a half of input voltage. These resonant circuits are operated by an interleaved PWM scheme. The output sides of these resonant circuits are connected in parallel to evenly distribute the input power, lessen current stresses on rectifier diodes and reduce copper losses of transformers. The ZVS turn-on through power switches and zero-current switching (ZCS) turn-off for rectifier diodes are accomplished through three series resonant tanks. Therefore, switching losses of MOSFETs and reverse recovery problem of rectifier diodes are reduced. The primary windings of two transformers are series-connected to balance the secondary winding currents. Finally, experiments based on a scale-down prototype are provided to verify the performance of the proposed converter.Power Electronics and Drive Systems (PEDS), 2013 IEEE 10th International Conference on; 01/2013