小波调制逆变器电压调制比的理论分析

Analysis of inverters’ voltage modulation ratio based on wavelet modulation

摘要:

为了分析基于小波调制的三相逆变器输出电压调制比,采用傅里叶分解的方法,先求解出输出相电压基波及各次谐波的解析式,然后利用得到的方程推导小波调制电压调制比M的计算方程,并通过计算得到M的范围,确定三相逆变器小波调制策略的线性调制范围,最后通过仿真验证理论分析的正确性与合理性．分析结果表明,在开关频率和调制比相同时,小波调制输出电压质量比SPWM和SVPWM更好,并且与SPWM和SVPWM相比,小波调制的线性调制范围更大．

Abstract:

First, the analytic expressions of fundamental wave and each order of harmonic wave for the output voltage is calculated by the Fourier decomposition method, which is used to analyze the modulation ratio of the three-phase inverter modulated by wavelet modulation. Then, the equation of the voltage modulation ratio (M) is derived and the scope of M is obtained by calculation, giving the range of the linear modulation for the three-phase inverter under the wavelet modulation. Finally, the correctness and rationality of the theoretical analysis is validated by computer simulation. The research result shows that the output voltage quality under the wavelet modulation is better than that under SPWM and SVPWM when the switch frequency is equal to the modulation ratio. In addition, the range of linear modulation under wavelet modulation is larger than that under SPWM and SVPWM.