改进型LST的谐波检测方法分析

Analysis of Harmonic Currents Detection Method Based on Improved LST

采用线性正弦跟踪(LST)的自适应谐波电流检测算法提高了谐波检测性能,但该算法中的误差分量的选取受到高次谐波的干扰,导致稳态误差是与高次谐波同频率的振荡信号。通过将低通陷波滤波器引进该算法中,反馈误差信号经过低通滤波器后抑制了高次谐波对算法性能的影响,根据劳斯-赫尔维茨稳定判据证明了算法的稳定性。理论分析和仿真结果表明,改进型算法解决了动态响应速度和稳态精度之间的矛盾。

Adaptive harmonic current detection algorithm using linear sinusoid tracer （LST） can improve the perfor- mance of the harmonic detection. However, the error in the algorithm is affected by the high order harmonics. As a re- sult, the steady-state error vibration signals have the same frequency as high order-harmonics. In this paper, a low- pass notch filter is included into the LST algorithm.The feedback error signal after low-pass filter restrains the high or- der harmonics effects on the algorithm. The stability of thealgorithm is also proved by Routh-Hurwitz stability criterion. The theoretical analysis and simulation results show that the algorithm can discard the contradiction between detecting accuracy and dynamic response.