Implementation of two-output three-level series-resonant inverter for induction melting application

Abstract

This study aims to present a two-output three-level series-resonant inverter together with an implementation and experiments for an induction melting application. A three-level circuit is applied for each branch of inverter in order to decrease the voltage stress on switching devices. A phase-shifted pulse-width modulation (PSPWM) with variable frequency control is applied for providing and maintaining a zero-voltage switching condition over a wide load range. In addition, the PSPWM could provide symmetrical output voltage and current waveforms that result in decreasing the THDv and THDi of output waveforms and harmonic losses of high-frequency transformer cores comparing to other PWM schemes. Finally, the prototype was designed, built, and tested to verify the consistency between the experimental results and theories of the proposed inverter.