Multi-objective optimization design for active damping LCL grid-connected
LCL filters, as the interface between the grid-connected inverters and the grid, overcome some of drawbacks of L or LC filters, especially have great performance used in medium and high power range situation. Methods of introducing passive damping and active damping are used to solving the stability problem around the resonance frequency. This paper purposed an active damping method based on introducing capacitor current feedback which can effectively control current resonance without changing the resonance frequency of LCL filter and avoid increasing wastage and reducing system efficiency. On the basis of above research, synthetically considering current attenuation ratio, transfer function amplitude and cost of the filter, the multi-objective optimization model of active damping LCL filter and optimization algorithm based on NSGA-Ċ are presented. Effectiveness of the optimization method is verified by simulations on PSCAD.