基于超前-滞后控制器的单相数字锁相环研究

Research on a single-phase digital PLL based on lead-lag controller

对于单相光伏并网逆变器而言,能够迅速而精确地追踪到电网电压同步信号的频率、相位,是保证其能够稳定运行是重要条件。常规的数字锁相方法主要是采用过零点检测这种模式,但由于其抗干扰能力弱,容易出现锁相失效的现象。针对这个现象提出了一种超前-滞后控制器、双二阶广义积分器(DSOGI)和改进瞬时无功理论相结合的方法,并且将这种方法应用于单相逆变器,仿真和实验验证了本方法能够快速有效地追踪到电网电压的同步信号,保障了整个系统精确性和稳定性。

Rapidly and accurately tracking the frequency and phase of grid-vohage is important condition for ensuring stable operation in single phase photovoltaic grid-connected inverter. Conventional digital phase-locked method mainly utilizes the pattern of detecting the zero-crossing point, but this way is weak in anti-interference and always appears the phenomenon of phase lock failure. To address this phenomenon, this article proposes a combined method with lead-lag controller, double second order general- ized integrator （DSOGI） and improved instantaneous reactive power theory. With the application in signal phase inverter, the simula- tion and experiment prove that this method can rapidly and efficiently follow the synch signal of grid-voltage and ensure the accu- racy and stability of the entire system.