Bi-directional power electronic transformer with maximum power-point tracking capability for induction heating applications

A single-stage commercial low frequency to high AC frequency bi-directional power electronic transformer (PET) for induction heating applications is proposed here. The proposed PET can simultaneously track the maximum power point and improve the output power factor by using a phase locked loop adjustable switching frequency controller. The operating principle of the PET is discussed based on mathematical equations and equivalent circuits. The experimental results of laboratory prototype, which converts 110 V/3ϕ/50 Hz input voltage to 20 V/1ϕ/22 kHz output voltage, show the capabilities of the proposed PET.