适用于光伏微网并网和孤岛运行的控制策略

A control strategy for grid-connected and islanded operation modes of photovoltaic micro-grid

光伏微网的谐波问题和孤岛运行逆变器间的环流问题变得越来越突出,提出一种含有串联逆变器和并联逆变器的并网接口,并对下垂控制环节进行改进。在光伏微网并网运行时,通过串联逆变器实现最大功率点跟踪,同时通过对并联逆变器的控制,达到消除谐波电流、补偿三相不平衡电流达到电能质量治理的目的。在光伏微网孤岛运行时,采用改进的下垂控制策略,即在下垂控制环节引入无功功率扰动环节来减小并网逆变器输出端电压幅值差,从而抑制环流,实现功率的自主分配。Matlab仿真结果验证了所提控制方法的有效性和可行性。

Harmonic problems and circulation problems between the photovoltaic micro-grid inverter is becoming increasingly prominent. A reactive disturbance part was introduced in the droop control process, and power quality management was achieved. It can achieve maximum power point tracking, and compensate harmonic current,unbalance currents to manage the power quality of point of common coupling（PCC） through the topology. Also, in the micro-grid islanded operation, the droop control strategy with reactive disturbance part was put out to suppress the amplitude differences of the output voltage between the PV sources. The control method was validated by simulation with Matlab/Simulink.