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 THD v and THD i 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.