Design methodology of P-res controllers with harmonic compensation for three-phase DC-AC grid-tie inverters with LCL output filter

This paper describes the modeling, control and operation of a grid-tie DC-AC inverter with LCL output filter. The proposed control system mitigates the impact caused by grid harmonic voltages. A current control approach with active damping based on the P-resonant controller with a cascaded notch filter is analyzed. In this approach the aim is to mitigate the effects of the resonance peak of the LCL filter and mains harmonics on the operation of the converter and on the quality of the electrical current injected into the power grid. The proposed P-resonant controller is designed and its parameters are obtained with an analytical methodology based on frequency response.