A Delay Compensation Method of the Grid-Connected Inverter with LCL Filter to Improve Robustness of the Impedance Shaping Control
Xie Wenhao1, Liu Yiqi2, Wang Jianze1, Ji Yanchao1, Yu Jilai1
1. School of Electrical Engineering and Automation Harbin Institute of Technology Harbin 150001 China; 2. College of Mechanical and Electrical Engineering Northeast Forestry University Harbin 150040 China
Abstract The impedance shaping control is capable to increase output impendence of the grid-connected inverter with LCL Filter, enhancing the harmonic-rejection-ability against the grid-voltage distortions. However, digital control method is applied with a control delay, which decreases the stability of the inverter as well as the output impedance at the frequencies above 1/6 of the sampling frequency (fs/6). In this paper, a discrete state predicting method for LCL filter is proposed to modify the virtual impedance by compensating the phase lag in control loop. The proposed strategy can effectively increase the output impedance to improve robustness of the impedance shaping control, and exhibit strong rejection ability of grid-voltage harmonics. Experimental results with a LCL-type three-phase grid-connected inverter verify the validity of the proposed strategy.
Xie Wenhao,Liu Yiqi,Wang Jianze等. A Delay Compensation Method of the Grid-Connected Inverter with LCL Filter to Improve Robustness of the Impedance Shaping Control[J]. Transactions of China Electrotechnical Society, 2017, 32(增刊1): 178-185.
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2017, Vol. 32 
