Preliminary study of H-bridges cascaded inverter with carrier phase-shift PWM for EAST fast control power supply

EAST (Experimental Advanced Superconducting Tokamak) fast control power supply is a large capacity single phase inverter power supply. The power system needs to keep on enhancing ability of fast response and output current with development of EAST. The difficulties of new power supply are high voltage and large current. To meet requirement of high voltage and fast response, the scheme of H-bridges cascaded inverter with IGBT (Insulated-Gate Bipolar Transistor) is presented. The technique of carrier phase-shift PWM (Pulse Width Modulation) based on DSP (Digital Signal Processor) is applied to decrease switching loss of IGBT, raise equal switching frequency of converter and improve performance of output wave. The analysis of harmonic and simulation are carried out, and the validity of proposed scheme and control strategy has been confirmed by experiments.