Series-resonant DC/AC inverter with an auxiliary resonant-switch cell for impedance drives

An impedance-loaded DC/AC inverter realized by a half-bridge series-resonant configuration is presented. The presented inverter is simple and without the cycloconverter. Two auxiliary power switches are installed across the resonant capacitor to achieve impedance-loaded drives. The synthesized sinusoidal voltage and current waveforms are composed of equal-amplitude quasi-sinusoidal pulses (QSPs) and the impedance-loaded resonant current robes, respectively. A frequency-modulated constant-on time control is adopted for gating the power switches to achieve ZCS during the resonant states, while the two auxiliary switches always turn on and off at ZVS. The power efficiency versus the output power is up to 92% under rated power and the total harmonics of the output voltage is under 8%