一种可实现微网系统快速平滑并网的主动同步控制策略

为实现微网系统从孤岛运行模式到并网运行模式的平滑过渡,微网与主电网的同步是首要考虑的问题。提出了一种新型基于锁相环原理的主动同步控制策略,该方法通过主动调节微网母线电压的频率、相角和幅值跟踪主电网电压,从而减小并网时刻的电压偏差,达到孤岛模式向并网模式的平滑过渡。同时,采用电压矢量叉积作为鉴相器,微网频率和相角可同时快速有效地跟踪电网频率和相角。并且该方案不需传递相位等时域信号,仅需依赖于低带宽的通信,原理简单、易于实施。最后,实时硬件在环仿真与实验结果表明,该控制方案可实现微网快速平滑并网。

An Active Synchronization Control Strategy for Fast and Smooth Integration of Microgrid

To guarantee a smooth transition from islanded mode to grid-connected mode, synchronization is the first issue to be considered. In this paper, a phase locked loop (PLL)-based active synchronization control approach is presented, which is implemented in the secondary control level of the microgrid hierarchical control structure by actively controlling the microgrid voltage to track the main grid. In this way, it can reduce the voltage difference to get the microgrid back into grid in minimum transient state. With the cross product of voltage vectors employed as the phase detector, the microgrid voltage frequency and phase are enabled to track the main grid at the same time. In addition, instead of fast communication to transmit signals in the time domain, the proposed method only needs a low-bandwidth communication link, which is simple and easy to implement. Finally, hardware-in-the-loop simulation and experiment results show the feasibility of the approach proposed.