Reference current regulation for inverter with virtual resistor damping control

Inverter with output LCL filter is widely used in power system. It has better switching frequency harmonic suppression effect, meanwhile it has resonance problem. Virtual resistor damping can suppress the resonance, but it affects the current control character, particularly for harmonic current. This paper develops the detailed models of the inverter with virtual resistor damping for output harmonic current control. Based on the analysis of current control loop with virtual resistor, the transfer function of current loop is obtained. Moreover, with the optimal value of virtual resistor, the performance of inverter is similar to 2nd order low pass filter. To control the output current equals to reference current, reference regulation method is proposed. At last, simulation and experimental results verify the correctness of theatrical analysis and effectiveness of the method.