面向微电网三相电压不平衡补偿的逆变器并网控制

随着微电网规模的日益扩大,单相、三相负载混用日益增多,微电网单相电压不平衡现象日益严重。为了解决这个问题,针对三相四桥臂逆变器三相输出可解耦独立控制的特点,提出并网逆变器三相输出可控互联、各相输出功率根据电压不平衡度进行自适应调节的控制方案。在建立其平均等效模型及不平衡状态转移模型的基础上,对逆变器三相输出电流进行分级控制,实现对微电网不平衡电压的补偿。利用MATLAB/Simulink进行了仿真,并构建实验平台进行了实验。仿真和实验结果表明,所提出的补偿方法具有很好的补偿效果。

Grid-connected Control for Inverters Oriented to Microgrid with Unbalance Compensation for Three-phase Voltage

With the increase in microgrid scale and mixture of single phase and three-phase load, the phenomenon of voltage imbalance of microgrid is becoming more and more serious. In order to solve this problem, a three-phase output interconnection and controllable scheme of grid-tied inverter is proposed by using the characteristic that output voltage and current of the three-phase four-leg inverter can be decoupled and controlled independently. The output power of each phase is adaptively controlled according to the voltage unbalance degree. On the basis of establishing the average equivalent model and the unbalanced state transition model, the grading control strategy of three-phase output current of the inverter is presented to compensate for unbalanced voltage of the microgrid. Simulation and experimental results show that the method presented is effective for voltage compensation. This work is supported by National Natural Science Foundation of China(No. 61374050).