一种简单可靠的并网测频锁相方法

A Simple and Reliable Locked-Phase Method for Grid-Connection Frequency Measurement

锁相技术作为光伏发电并网的关键技术,其相位的准确锁定和频率精确检测是保证并网成功的关键。常用锁相电路存在检测频率不稳及锁相精度不准的缺点,并且软件滤波使用数据量大、实时性差。为解决以上问题,文章提出了基于滑动平均滤波控制算法的锁相电路设计,此方法硬件电路简单、准确,解决了过零比较器输出方波边沿振荡问题;软件控制算法简洁、控制实时性好。实验表明:该方法频率检测准确、锁相稳定可靠。

As the key technology of PV power generation grid-connection, the accuracy of phase lock and frequency detection is the key for successful grid generation. However, the common phase lock circuits have the shortcoming of instability in frequency detection and low accuracy of phase locking; also need for large amount of data in software filtering, and poor in real-time performance. In order to solve the above problems, the phase locked circuit based on the control algorithm of moving average filter is proposed in this paper through a large number of experiments, this method is simple and accurate in hardware circuit, has solved the edge oscillation issue of zero comparator output pulse edge; in the same time the software control algorithm is simple and has good real-time control. Experiments show that the method is accurate for frequency detection and is stable and reliable for phase locking.