Showing papers by "Huai Wang published in 2008"
TL;DR: In this paper, a highvoltage zero-voltage-zero-current-switched dc-dc converter with low voltage stress is presented, where the voltage stress on each switching device is only one-third of the input voltage and the main advancements of the proposed converter have also included wider soft-switching range and elimination of circulating energy on the primary side during the freewheeling stage.
Abstract: A high-voltage zero-voltage-zero-current-switched dc--dc converter with low voltage stress is presented in this paper. Its circuit structure is extended from a previously developed zero-voltage-switched dc--dc converter consisting of six series-connected switching devices, one three-phase transformer, and an output current tripler. The voltage stress on each switching device is only one-third of the input voltage. Compared with the previous converter, apart from retaining the advantage of having low voltage stresses on the switches, the main advancements of the proposed converter have also included (1) wider soft-switching range; (2) elimination of circulating energy on the primary side during the freewheeling stage; and 3) use of phase-shift pulsewidth modulation in output voltage control. Detailed topological operations and steady-state characteristics of the converter will be given. A 2.2-kW, 990-V/110-V dc--dc converter prototype has been built and tested. Experimental results are favorably compared with the theoretical predictions.
37 citations
15 Jun 2008
TL;DR: In this paper, a soft-switching full-bridge current-driven DC-DC converter is proposed for high voltage and high power applications: its power transistors turn on/off with ZCS, what is suitable for IGBT switches.
Abstract: A new soft-switching full-bridge current-driven DC-DC converter is proposed for high voltage and high power applications: its power transistors turn-on/off with ZCS, what is suitable for IGBT switches. An active snubber formed by two active switches and one capacitor is inserted in the primary side of the converter. The snubber's accumulated energy is proportional to the input current, what allows ZCS at a very wide line and load range, by minimizing the required energy: for each value of the input current and load, the snubber's capacitor is charged only at the minimum voltage necessary for achieving ZCS. Thus, the level of the snubber energy necessary for soft-switching is self-adaptable. The duration of the resonant stages required for achieving the ZCS conditions are very short and independent of the values of the input current and load. No resonant current peaks appear. The experimental results obtained on a 3 kW prototype, built for the input voltage of 250 V and output voltage of 15 kV, confirmed the expected performances.
16 citations