基于I_p-I_q法谐波检测中数字低通滤波器的设计及其DSP实现

Design of digital low pass filter in harmonic detection based on I_p-I_q transformation and its implementation using DSP

针对基于Ip-Iq法的谐波检测在有源电力滤波器的应用,利用Matlab仿真软件建立仿真模型,分析低通滤波器的选择、设计及其对谐波检测的影响可知,不同类型的低通滤波器,以及滤波器的阶数、截止频率对谐波检测的动态过程和精度都有一定影响。综合考虑谐波检测的要求,选用契比雪夫低通滤波器进行仿真,结果表明:该滤波器阶数越高响应速度越快,但在通带内存在高次谐波;阶数越低响应速度越慢,但通带响应较好。在仿真的基础上给出了用数字信号处理芯片(DSP)实现基于Ip-Iq法谐波检测的方法和结果,实验结果验证了仿真的正确性和低通滤波器对检测结果的影响。

A simulation model is established with Matlab for Ip-Iq transformation-based harmonic detection in active power filter. The selection and design of low pass filter as well as its influence on harmonic detection are analyzed. Results show that, the type ,order and cut-off frequency of low pass filter all do affect the dynamic response and precision of harmonic detection. According to requirements of harmonic detection,the Chebyshev low pass filter is selected for simulation. Results show that,the higher order the filter has,the faster the response will be and the more high-order harmonics in the passband. The Ip-Iq transformation-based harmonic detection is implemented with digital signal processor,and the experiment result proves the correctness of simulation and obtained conclusions.