Design and Active Compensation of LCL Filter for Grid-Connected Inverter

Grid connected inverter with an LCL filter can attenuate high frequency harmonics generated by the high frequency switching on and off.The design criterion and calculation procedures of LCL were introduced in detail.But the LCL filter is a third order system,which means it is easy to resonate.In order to increase the damping and eliminate the resonance of LCL filter,a method with filter capacitor current feedback was adopted.All the theoretical analysis was verified by experimental results on a single phase 1.5 KVA grid-connected inverters with an LCL filter.