大功率冲击性负荷低频间谐波检测方法

Detection Method for Low Freuency Interharmonics Under High Power Impact Load

低频谐波近基波,常呈现幅值小、非平稳,且呈现旁瓣复杂等特征,难以精确实时提取,不易实施针对性的补偿措施。本文着眼于大功率冲击负荷电源系统中出现的这一低频检测难题,研究了基于余弦型FIR带通(cosinebandpassFIR,CBP-FIR)滤波器的检测算法,其具有固定的中心检测频率及快速的响应速度。考虑到实际工况,提出了具有可调中心频率及相位偏移系数的改进型余弦FIR带通(improved cosine bandpass FIR,ICBP-FIR)检测算法。ICBP-FIR算法具有良好的谐波检测精度、系统稳定裕度及动态鲁棒特性,同时能保证间谐波相位补偿,并通过边界优化有效剔除干扰信号,实现有效的频谱分离。利用Matlab为设计过程进行了优化,使用基于DSP的数字分析系统进行了试验验证,验证了检测算法的正确性和有效性。

Low⁃frequency harmonics which are close to fundamental usually present characteristics of small amplitude,non⁃stationary state and complex side⁃lobe inter⁃harmonics.In order to ensure the precise and real⁃time extraction of the whole spectrum band,the specific compensation measure is difficult to implement.Aiming at this detection problem caused by operation of high⁃power shock load power supply system,the detection method based on cosine bandpass FIR(CBP-FIR)filter is researched,which has fixed central frequency and fast response speed.Considering the real working condition,the improved cosine bandpass FIR(ICBP-FIR)filter with adjusted central frequency and phase⁃shift coefficients is pro⁃posed.ICBP-FIR filter has excellent harmonic detection precision,system stability margin and dynamic robustness characteristics,which can effectively guarantee phase compensation of inter⁃harmonics.The in⁃terference signals can be eliminated by boundary optimization of ICBP-FIR filter to achieve effective spec⁃trum separation.The validity of the detection algorithm is verified by experiments with analysis system based on DSP.