基于小波变换和HHT的光伏并网谐振检测方法

Detection method of PV resonance based on wavelet transform and HHT

分布式光伏发电并网系统是一个复杂的高阶LC网络,输出大量高次谐波,当某一次谐波频率恰好与网络固有谐振频率重合,系统会发生严重的谐振。针对分布式光伏发电并网的谐振检测问题,建立光伏谐振的数学模型,根据小波变换(WT)的多分辨率特点和希尔伯特黄变换(HHT)完全自适应性优势,提出一种基于WT和HHT相结合的谐振检测方法。仿真分析和实验结果表明,该方法可以快速准确地检测出谐振频率和幅值。

Distributed photovoltaic power generation and grid-connected system is a complex higher-order LC network, which contains large number of high harmonics. When a harmonic frequency coincides with the natural resonance frequency of the network, the system has a serious resonance. Aiming at the resonance detection of distributed photovoltaic power generation grid-connected system, the mathematical model of the resonance was established in this paper. And a novel resonance detection method based on the wavelet transform and Hilbert-Huang transform（HHT）was proposed, because of the multi-resolution characteristics of wavelet transform and the complete adaptability of HHT. Simulation analysis and experimental results showed that the proposed resonance detection method can quickly and accurately detect the resonance frequency and amplitude.