交直流微电网互联变流器控制策略

Control Strategy of Interlinked Converter for AC/DC Microgrid

交直流混合微电网是未来智能电网的重要组成部分,文中给出了交直流混合微电网的典型拓扑和4种运行模式,并对每种运行模式的功率平衡关系进行了详细分析。针对低压交直流微电网中阻抗比通常较大的特点,设计了适合低压微电网的电压—有功功率控制策略。对交直流混合微电网中互联变流器的功率传输关系和控制作用进行了深入分析,提出了适用于交流微电网和直流微电网之间互联的新型控制策略。根据互联变流器直流侧电容在功率交换中的作用,推导了传输功率与两侧电压之间的函数关系。在PSCAD/EMTDC仿真平台上进行了仿真分析,结果表明,在混合微电网脱离大电网的情况下,互联变流器能够很好地维持交直流两侧功率平衡,保证了交直流两侧电压质量。

The hybrid AC/DC microgrid is an important part of the future smart grid.This paper is concerned with the typical topology and operation mode for the hybrid AC/DC microgrid.Then,the power balance relationship in each operation mode is analyzed in detail.Because of the large impedance ratio in the low voltage grid,a voltage and active power control system is designed and the power exchange and control of the interlinked converter is enunciated.Finally,a new AC/DC droop control strategy is proposed.The strategy gives the power-voltage droop relationship based on the function of the capacitor in the power transmission between AC side and DC side.The proposed control algorithm is verified on a PSCAD/EMTDC simulation platform,which shows that the interlinked converter can accurately maintain the power balance between the AC side and DC side based on the voltage information of both sides,thus guaranteeing the voltage quality of the AC and DC microgrid.