电网电压不对称故障下软件锁相技术

摘要

The operational principle,advantages and disadvantages of traditional SPLL (Soft Phase Locked Loop) are analyzed. The SPLL based on integer coefficients filter is proposed to restrain the effect of negative sequence component on the detection accuracy of phase locked loop in three-phase asymmetry fault. The method of zero-pole cancellation is- applied in the design of low pass integer coefficients filter to suppress the second harmonic converted from the negative sequence component and improve the anti-interference ability and detection accuracy of phase locked loop. Due to the small computation load of integer coefficients filter, it affects little on the real-time performance of SPLL. Experimental results verify its feasibility.%介绍了传统软件锁相环(SPLL)的工作原理及优缺点,针对电网发生三相不对称故障情况下负序分量对锁相环检测精度的影响,提出基于整系数滤波器的SPLL.通过零极点对消的方法设计出低通整系数滤波器来抑制由负序分量转换而来的2次谐波,提高了锁相环的抗干扰能力和检测精度.由于整系数滤波器运算量小,其对SPLL的实时性影响很小.实验结果验证了所提方法的可行性.