High power factor control using load resonant frequency auto tracking phase shift inverter

This paper proposes a new method for frequency control and for output power control using a load resonant frequency auto tracking phase shift inverter. The proposed method employs a phase shift inverter with a single output current sensor. The fundamental waveform signal of the output voltage of a phase shift inverter is generated by using the proposed method because the conventional method produces an output voltage that has a pulse waveform. The proposed control strategy to utilize load resonant frequency easily achieves unity power factor control with high efficiency. In the proposed method, the fundamental waveform signal of the inverter output voltage coincides with the detected inverter output current wave form. Moreover, as the inverter output power is regulated by controlling the phase angle of each inverter leg using the proposed method, soft-switching control can be realized. The experimental results presented in this paper confirm the validity of the proposed methods.