An Improved Distributed Secondary Control Method for DC Microgrids With Enhanced Dynamic Current Sharing Performance

作者：Wang, Panbao^*; Lu, Xiaonan^*; Yang, Xu^*; Wang, Wei^*; Xu, Dianguo^*

来源：IEEE Transactions on Power Electronics, 2016, 31(9): 6658-6673.

DOI：10.1109/TPEL.2015.2499310

• Current sharing
• dc microgrid (MG)
• droop control
• low-bandwidth communication (LBC)
• secondary control

This paper proposes an improved distributed secondary control scheme for dc microgrids (MGs), aiming at overcoming the drawbacks of conventional droop control method. The proposed secondary control scheme can remove the dc voltage deviation and improve the current sharing accuracy by using voltage-shifting and slope-adjusting approaches simultaneously. Meanwhile, the average value of droop coefficients is calculated, and then it is controlled by an additional controller included in the distributed secondary control layer to ensure that each droop coefficient converges at a reasonable value. Hence, by adjusting the droop coefficient, each participating converter has equal output impedance, and the accurate proportional load current sharing can be achieved with different line resistances. Furthermore, the current sharing performance in steady and transient states can be enhanced by using the proposed method. The effectiveness of the proposed method is verified by detailed experimental tests based on a 3 x 1 kW prototype with three interface converters.

• 出版日期2016-9
• 单位哈尔滨工业大学