CLASS-D ZERO-VOLTAGE-SWITCHING INVERTER WITH ONLY ONE SHUNT CAPACITOR

A class-D zero-voltage-switching (also called soft-switching) inverter with only one capacitor in parallel with either transistor, along with an approximate analysis and experimental results, is introduced. The inverter offers both zero turn-on and zero turn-off switching losses, yielding high efficiency at high frequencies. In addition, soft switching reduces switching noise associated with the high-frequency ringing at the switching instants. The transistor voltage stresses are low, similar to those in conventional class-D and pulse-width-modulated inverters. This permits the use of low-on-resistance MOSFETs, reducing the conduction losses. A 50 W class-D inverter was built and tested. The theoretical and experimental results were in good agreement. The inverter combines, low transistor peak voltages and low conduction losses, as in PWM converters, with low switching losses and low noise as in single-ended resonant convertors.