Active damping of LCL filter without Capacitor Voltage Sensors Three-Phase PWM Inverter

In this paper, new sensorless active damping method of grid connected LCL filter for 3-phase PWM inverter is proposed. In the proposed method, the resonance component of capacitor voltage of LCL filter can be observed by a simple MRAS(Model Reference Adaptive System) observer without additional hardware sensors. The active damping can achieve by feed-forward compensation of the observed capacitor voltage in current controller. The validity of the proposed method is proven by simulation and experiment on the 3-phase PWM inverter system