A self-adjusting sinusoidal power source suitable for driving capacitive loads

A new self-adjusting current-fed push–pull parallel inverter (SA–CFPPRI) is presented and tested by simulation and experimentally. The power source includes a soft switching control circuitry and a controllable inductor. The SA–CFPPRI can drive a capacitive load at any frequency within the design range. It will maintain zero voltage switching of the main transistors and follow the input frequency signal even when the resonant elements and/or the load vary. Possible range of applications for the proposed power source is: piezoelectric transformers and motors, ac bus for a distributed power system and other loads that need to be fed by a sinusoidal waveform. The experimental results of the laboratory unit (160 Vrms at 93 kHz and nominal output power of 5W) verify the analytical analysis and proposed design procedure.