New soft-commutation and high-efficiency phase-shifted full-bridge converter using output-voltage-doubler

Abstract

Recently, the plasma display panel (PDP) has brought more and more attention to the large area wall-hanging display area, constantly being developed for larger screen, higher resolution, thinner thickness, and lighter weight. However, as the panel size and the resolution are increased, the power consumption is also increased with a square ratio. Especially, most of the power is consumed during the sustaining operation, where the high voltage sustaining pulses are required for a PDP to emit light to discharge gas in cells. Therefore, the PDP sustaining power module (PSPM) should realize the high power density, high performance, and high efficiency over wide load ranges. Among various PWM DC/DC converters hitherto developed for middle/high power application such as the PSPM over 400 W, the conventional Phase-Shift Full-Bridge (PSFB) converter is widely used, which provides all switching devices with the ZVS operation at the high frequency using the parasitic components. However, although the leading leg switches are easy to achieve ZVS with the use of reflected large output inductor current, the lagging leg switches are difficult to achieve ZVS under the light load condition because only the energy stored in the small leakage inductor is used. Therefore, since this converter is required to have the large leakage inductor to achieve the ZVS of lagging leg for the wide load range, it has several serious problems such as the large circulating energy, effective duty cycle loss, and serious parasitic ringing across the output rectifiers. To solve all these problems, this dissertation proposal suggests a new phase-shifted two-transformer full-bridge converter employing the output-voltage- doubler. Firstly, a ZVS and soft-commutating two-transformer full-bridge PWM converter using output-voltage-doubler is proposed. It achieves the ZVS operation of lagging leg along the whole load ranges using the energy stored in the magnetizing inductor of transformers. Moreover, ...