Modelling of asymmetrical pulse width modulation with frequency tracking control using phasor transformation for half-bridge series resonant induction cookers

A FPGA-based asymmetrical pulse width modulation (APWM) with frequency tracking control method is introduced for half-bridge series resonant induction cookers. Two control loops within FPGA are implemented. Phase-locked loop (PLL) is used as frequency tracking control to keep ZVS over wide range, APWM as power regulation. Large and small signal PSPICE compatible circuit model are obtained by phasor transformation. Dynamic models for half-bridge series resonant induction cooker are extracted from these circuits, and their characteristics are analysed. Finally models are verified and conclusions are given.