PWM algorithms for indirect matrix converter

This paper presents a novel PWM algorithm for indirect matrix converter (abbreviated to IMC) is proposed. Generally, PWM algorithm for the rectifier is based on two larger source line voltages without zero vectors. In this paper, when considering the PWM algorithm for the rectifier, the inverter and motor can be seen as constant current load in DC link. When considering the PWM algorithm for the inverter, the rectifier and input LC filters can be seen as constant voltage source in DC link. Then the inverter can be controlled as a voltage-source PWM converter. SVM based on current can be applied for the rectifier. SVPWM is applied in the inverter. The modulation indexes for rectifier and inverter need the voltage and current in DC link. But the voltage and current in DC link are pulses, and sampling for them is difficult. In this paper, DC link voltage is reconfigured by the input phase voltages and switching status of the rectifier. DC link current is reconfigured by the output currents and switching status of the inverter. There are three PWM sequences for indirect matrix converter. First, SVM for rectifier and SVPWM for inverter are independent. The bi-directional switches in rectifier needs four-step commutation and commutation in inverter is hard switching commutation. Second, zero current switching commutation for the bi-directional switches in rectifier can be achieved. The rectifier only needs two-step commutation. Third, zero voltage switching commutation for the common IGBT in inverter can be achieved. Each PWM sequence for indirect matrix converter is investigated. Simulations for three PWM sequences and experiments for the second PWM sequence have been done. The results verify the analysis of the PWM algorithms.