A novel approach to practical matrix converter motor drive system with reverse blocking IGBT

This paper proposes a novel control strategy and a protection circuit, and also shows the advantage of utilizing (newly developed) reverse blocking IGBT (RB-IGBT), to solve several practical problems of the matrix converter. The proposed control strategy is based on a virtual indirect control method with a virtual rectifier and a virtual inverter. PWM pulses for the matrix converter are obtained by combining PWM pulses for the virtual rectifier and inverter. As a result, the input current and the output voltage can be controlled independently. The advantage of those methods is confirmed by experimental results with a 750 W induction motor drive system. Good sinusoidal waveforms are obtained for the input and output currents, and the T.H.D. of the input and output current are 5.1% and 1.4%, respectively. The conduction loss of the RB-IGBT is decreased to about 2/3 of the conventional AC switch with series connection diode. Thus, the converter is about a half to the conventional PWM rectifier-inverter system with the same capacity. Furthermore, the protection problem is solved by a dynamic clamp method without an electrolytic capacitor. This protection circuit directly dissipates reactive load energy by dynamic clamp operation of an IGBT.