较为详细地介绍了单同步坐标系软件锁相环，采用了单一的同步坐标系锁相控制结构，一般适用于电网电压平衡时的相位，频率及幅值的检测，以及用于多种控制结构中（下垂控制，PQ控制，双闭环控制）。-A more detailed descr iption of the principle of a single coordinate system PLL synchronization and setting PI controller parameters. SPLL with a single synchronous coordinate system lock control structure, generally applicable to the detection phase, frequency and amplitude of the grid voltage at equilibrium, as well as for a variety of control structures (droop control, PQ control, dual loop control).