一种基于软件锁相环的电网频率动态检测方法

Method of frequency dynamic detection based on software phase-locked loop

文中提出了一种基于软件锁相环的电网频率动态检测方法,并对频率测量的分辨率进行了详细分析。该方法在三相软件锁相环的基础上,利用数字信号处理芯片TMS320F2812的定时器计数值与三相软件锁相环的PI调节器输出的误差角频率的对应关系,实现定时器周期中断,每中断一次加一个固定角度。通过改变实现周期中断的定时器的周期计数值,实现电网频率的动态检测。该方法无需额外的硬件电路,测频方法简单,实时性强、误差较小,实验结果证明了该方法的可行性。

This paper implements a dynamic frequency detection method based on software phase-locked loop（ SPLL）,and analyses the resolution of frequency measurement in detail. The method uses the correspondence between the TMS320F2812 timer counts and output error of the angular frequency of PI regulator with three phase-locked loop to realize timer periodic interrupt and adds a fixed angle once a interrupt. The frequency detection can be realized by altering the timer counts of the periodic interrupt. There is no need for extra hardware integrated circuit in the novel method and the frequency measurement method is simple,practical with small error. The experiments show that the method is feasible.