Application of IGCT in High Power Rectifiers

This paper investigates the possibility of applying IGCT (Integrated Gate Commutated Thyristor) into high current high power rectifier systems. The optimal power converter topology that fully utilizes the functionality of IGCT is proposed. The proposed power converter consists of a front-end diode rectifier and 3-level step-down DC/DC converter. As compared to 2-level operation, half the input DC voltage and twice the effective switching frequency of 3-level operation can provide a wider operation range of continuous conduction mode resulting in a higher average output current of less ripple size than 2-level case. A laboratory proto-type of 5 kA, 3.1 MW rectifier has been simulated and tested to confirm the feasibility of IGCT in the proposed power converter topology. The proposed solution generates a relatively smooth output DC current with less contents of high frequency harmonics, thereby avoiding the high frequency harmonic related problems found in IGBT based high current rectifiers. IGCT would play a significant role to improve the cost-effective performance and reliability in low and medium ranged high current high power rectifier systems.