光伏发电自治微电网逆变器的谐波均流控制

首先定性分析了微电网逆变器的功率传输特性,证明了微电网逆变器均流控制最关键的是解决各DGs(distributed generations)线路阻抗不平衡时的均流问题,进而提出了一种简单可行的电流直接前馈式均流控制策略,不仅省却了传统下垂控制中所需要的功率计算与电压合成计算,而且可以在确保频率恒为50 Hz的前提下实现并联逆变器间的电流均衡;然后详细分析了虚拟阻抗对均流的作用,提出无滤波器的谐波均流控制,并将其与有滤波器的谐波均流算法进行了对比分析;最后,采用Matlab/Simulink仿真软件进行了仿真验证。仿真结果证明了该控制策略的合理性与有效性。

Harmonic Current-sharing Control of Inverters in Autonomous Microgrid of Photovoltaic Power Generation

Firstly, the power transfer characteristic of the interface inverters applied to microgrid was qualitatively analyzed this paper, proving that the unbalance of line impedance is the key problem of the current-sharing control of micro-grid inverters. Then, a simple and feasible direct current feedforward current-sharing control strategy is proposed whic can not only eliminate the calculations of the active power, reactive power, and the voltage synthesis in conventional droop control, but also fix frequency at 50 Hz while achieving the current balance between the parallel inverters. In addition, the effect of virtual impedance on current-sharing was analyzed in detail and a harmonic current-sharing control was proposed without a filter. The contrast analysis was done to the proposed sharing control strategy and the harmonic current-sharing methods with a filter in detail. Finally, the simulation results in Matlab/Simulink verify the rationality and effectiveness of the proposed control.