A multi-resonant PR inner current controller design for reversible PWM rectifier

The PWM rectifier with LCL filter has the ability to attenuate the high-frequency current harmonics. However, the model of the system is very complex due to the coupling of the LCL filter under rotating coordinate system. The inner current controller under stationary frame is chosen and it can also easily suppress the negative sequence current under such condition. In order to eliminate the steady error and current distortion caused by harmonics of the grid voltage, a Multi-resonant PR Inner Current Controller was used. Because the system is of high order and complicated, it is difficult to determine the parameters of the regulator. After discussing the function of parameters, this paper proposed an easy method to design the PR regulator parameters separately, which can guarantee the stability of the system and the performance of the inner current loop. A 1.5-kW experimental prototype has been tested to verify the effectiveness of the proposed method.