Improvement Control of Dual-Direction DC-AC Converters for Microgrids
Yang Gang1, Yang Qixun1, Zhang Tao2, Liu Shu2, Zhang Heng3
1.State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing 102206 China 2.Beijing Sifang Automation Co.Ltd Beijing 100084 China 3.State Power Economic Research Institute Beijing 102209 China
Abstract：In the dual-direction DC-AC converter used to connect the DC microgrid and the AC grid, the AC voltage and DC voltage harmonics will generate lower-order harmonics in the AC grid current of the DC-AC converters. In order to tackle the problem, the grid current expression of the DC-AC converter considering the AC and DC dual side voltage harmonics is deduced for the first time and the essence and character of this effect have been revealed. The proportional-integral-dual repetitive control strategy is introduced into the d and q axis of the grid current to control the grid current of the DC-AC converter. Furthermore, aiming at the problem that the non-integral ratio of the sampling and fundamental frequencies in the digital system will decay the gain of the repetitive controller, a gain enhancement approach for the repetitive controller with the desirable sampling point linear interpolation algorithm is proposed to improve the performance of the repetitive control in terms of cancelling the grid voltage harmonics. Detailed simulation and experimental results validate the accuracy and validity of the theoretical analysis and the improvement scheme of the AC grid current waveform quality of the DC-AC converter.
杨刚, 杨奇逊, 张涛, 刘树, 张恒. 微网中双向DC-AC变流器的性能优化控制[J]. 电工技术学报, 2016, 31(7): 81-91.
Yang Gang, Yang Qixun, Zhang Tao, Liu Shu, Zhang Heng. Improvement Control of Dual-Direction DC-AC Converters for Microgrids. Transactions of China Electrotechnical Society, 2016, 31(7): 81-91.
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2016, Vol. 31 
