Phase-Shift-Controlled Three-Level Converter With Reduced Voltage Stress Featuring ZVS Over the Full Operation Range

The simplicity of phase-shift control at fixed switching frequency and 50% duty-cycle operation is fully exploited by the proposed converter topology. The transistor voltages are clamped to only 50% of the dc input, the dc bus capacitive dividers being naturally stabilized. Furthermore, zero-voltage switching for all switches is guaranteed from no-load to full-load conditions, that is to say, from zero to nominal output voltage and from zero to nominal load current. As such, the proposed topology is an excellent candidate for demanding applications as compact battery chargers for electric vehicles. Experimental results obtained from a 400-80-V/0-360-V/2-kW/100-kHz prototype support the theoretical analysis.