Dual-loop Control Strategy for Grid-connected Inverter with LCL Filter

Qiubo Peng, Hongbin Pan, Yong Liu, Lidan Xiang

Key Laboratory of Intelligent Computing & Information Processing of Ministry of Education, Xiangtan University, Xiangtan, China.

DOI: 10.4236/epe.2013.54B019                

Abstract

As to the concrete topology of three-phase LCL type grid-connected inverter with damping resistance, mathematical model was deduced in detail, using method of equivalent transformation to the structure diagram, damping resistance was virtualized, mathematical model under the DQ frame that can realize decoupling control was established, a dual-loop control strategy for grid-connected inverter with LCL filter was proposed, the system stability was analyzed and the design method of controller was given. The proposed method overcame the flaws of loss increase, efficiency reduce and cost increase which were caused by damping resistance in LCL type grid-connected inverter, the system efficiency and power supply quality of the output were improved. Feasibility and effectiveness of the new method were validated by simulation and experimental results.

Keywords

Virtual Damping; LCL Filter; Three-phase Grid-connected Inverter; Decoupling Control

Conflicts of Interest

The authors declare no conflicts of interest.

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