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

Abstract

Abstract-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 5 W) verify the analytical analysis and proposed design procedure.Index Terms-Phase comparator, push-pull parallel resonant inverter (PPPRI), sinusoidal power source, variable inductor.

Push–Pull Inverter Using Amplitude Control and Frequency Tracking for Piezoelectric Transducers

“…However, this method has limitations when the driving frequency is higher than the transducer frequency and requires more control circuits for compensation. Ben-Yaakov et al proposed a self-regulating push-pull inverter that matches the resonant element through a variable inductor [15]. The frequency can be tracked even if the resonant element and load change.…”

A low-power, self-tuning resonant driver for generating sinusoidal pulse trains with piezoelectric element loads

“…As such, PE presents a capacitive load to the driver. Several driver circuits suitable to drive capacitive loads were previously suggested in the literature [2][3][4]. The basic currentfed push-pull resonant inverter [2] for example, performs well when the capacitance and the resonance frequency are constant.…”

“…However PEs are nonlinear loads, and as a result, a change in load capacitance and resistance shifts the resonant frequency, amplitude and generally the waveform applied to the load. One solution is to apply a bias winding to regulate the effective inductance of the resonant inductor to tune to the PE frequency [3]. However this method requires extra power dissipation to hold the inductor at the desired operation point.…”