An LCL filter with an active compensation for a fast charger station

For the AC/DC stage of a 50 kW fast charger station which is a three-phase pulse width modulated (PWM) converter, an LCL filter is designed and constructed. As a PWM converter, the rectifier is a source of high frequency harmonics demanding filtering action to meet the grid regulations. Hence, the required filtering specification by the LCL filter is extracted using an appropriate harmonic model of the converter. The design procedure and the filter transfer function are presented. In addition, an active compensator is proposed to enhance the converter power factor by modification of the reference q current. Some simulation results are provided to show the effectiveness of the filter.