A study of startup inrush current of three-phase voltage source PWM rectifier with PI controller

Usually, the control method with voltage and current PI regulators in synchronous rotating frame is applied to three-phase voltage source PWM rectifier. It is easy to generate inrush current during startup period. A slow ramp reference current is commonly used to achieve the soft starting, but not quite effective. The paper first analyzed the cause of inrush current and obtained the shortcomings of traditional PI method and slow ramp reference method. Then a feedforward compensation was proposed to decrease the inrush current. After analysis and comparison, the feedforward compensation method has the best performance. Finally, an experimental prototype of a three-phase voltage source PWM rectifier controlled by a TMS320F2812 DSP was built and tested. The experimental results verified the validity of the analysis.