无锁相环同步坐标变换检测法的硬件延时补偿

Delay Compensation for Harmonics Detection Based on Synchronous Reference Frame Without Phase Lock Loop

针对谐波检测电路遇到的硬件电路延时和锁相环检测误差问题,分析了无锁相环同步坐标变换检测方法对结果的影响,并引入通用瞬时无功理论中的波形相关系数概念,分析了硬件延时对补偿效果的影响,最终提出了一种无锁相环的、考虑硬件延时补偿的改进型同步坐标变换检测法。该方法通过预设同步坐标旋转角速度,避免了锁相环的检测误差,同时在同步坐标逆变换矩阵中引入相位补偿角对硬件延时进行补偿,具有实施简单、适合数字控制、测量准确,且不受电网电压畸变影响的特点。

The phase lock loop detection error and the time delay often occur in the digital control circuit for harmonics detection. To mitigate the influences of the two problems, the performance of the harmonics detection method without phase lock loop was discussed, and on the basis of the universal instantaneous power theory, the effect of the time delay on the reference compensation current signal was investigated. Then an improved synchronous reference frame method for harmonics and reactive currents detection was proposed, in which there is no phase lock loop and took the time delay into account. The phase lock loop detection error was avoided by set the rotation speed of the synchronous reference frame in advance and the time delay was compensated by importing the compensatory angle in the inverse transform. This method is easy to be implemented for digital control application and is not affected by the distorted source voltage. The simulation results have also shown its accuracy and feasibility.