Method and device for reducing switching loss of phase-shifting full-bridge converter

Abstract

The invention provides a method and a device for reducing the switching loss of a phase-shifting full-bridge converter. The device comprises a resonant capacitor voltage detection unit, a judgment unit, a control arithmetic unit and a signal production unit, wherein the signal production unit comprises a phase-shifting signal production unit, a dead zone signal production unit and a phase-shifting trigger pulse production unit. The method comprises the following steps of: detecting resonant capacitor voltage signals by the resonant capacitor voltage detection unit; judging the size of the voltage signals by the judgment unit; calculating the optimum dead zone time of an upper switching tube and a lower switching tube of the same bridge arm in two bridge arms by the control arithmetic unit; and producing phase-shifting trigger pulse signals by the signal production unit to ensure that the withstand voltage is the lowest when the switching tubes are switched on, so the aim of reducing the switching loss is achieved. A phase-shifting control technique which is fixed relative to the dead zone time can provide the optimum dead zone time, and according to the technique, the switching loss is reduced to the lowest, the soft switching range is enlarged, and the working efficiency of the converter is improved; and the phase-shifting control technique is particularly suitable for high-power phase-shifting full-bridge converters.

Description

technical field [0001] The invention relates to the technical field of DC-DC converter conversion, in particular to a method and device for reducing switching loss of a phase-shifted full-bridge converter. Background technique [0002] With the introduction of the full-bridge ZVS phase-shifting technology, this technology has been widely used in the high-power field. By introducing resonant inductance and dead time into the phase-shifted full-bridge converter, the switching tube can be turned on at zero voltage, but it is difficult to turn on the switching tube at light load, and there is still a large switching loss, so it is not applicable It is suitable for occasions where the load and power supply voltage fluctuate in a large range. [0003] It is difficult to achieve ZVS in the lagging arm of the converter under light load conditions, which is related to the resonant inductance, the size of the resonant capacitor, and the dead time of the trigger pulse of the switching...

AI Technical Summary

Problems solved by technology

[0004] The root cause of this problem is the defect of the PSFB-ZVS converter topology itself. There are problems such as the load range and duty cycle loss achieved by soft switching. The factors that affect these problems are the resonant inductor and the resonant capacitor.

The dead time usually used is fixed, and when the resonance parameters change, the lagging arm tube of the converter cannot complete zero-voltage turn-on under light load or even heavy load.

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