Improved Phase-Shift PWM Converter for Larger Sized PDP Slim Sustain Power Module

New phase-shift pulse width modulation (PWM) converters with a wide zero voltage switching (ZVS) range for the slim sustain power module of over 63-in plasma display panel (PDP) are proposed in this paper. Each proposed converter is composed of two symmetric half-bridge converters (TSHBCs) that are placed in parallel on the primary side and are driven in a phase shifting manner. Two power transformers are connected in series on the secondary side. All the switches in the proposed converters can be turned on with ZVS under all load conditions, while the conduction loss caused by the assistant current source extending the ZVS range can be minimized. Moreover, because the turns ratio of the transformers can be designed to be better than that of the counterparts, the voltage stress across the secondary rectifier diode and the primary conduction loss can be reduced. A low-profile design is also achieved due to the use of the two small-sized transformers, which results in a slim power supply. In this paper, the circuit configurations, operation principle, relevant analysis results, and design example of the proposed converters are presented. Experimental results demonstrate that the proposed converters can achieve a significant improvement in the efficiency for a prototype converter realized with the specification of 80-in PDP sustain power module (320-385 V dc input, 205 V dc /5 A output).