混沌PWM逆变器输出电压功率谱密度分析

逆变器采用混沌PWM(pulse width modulation)调制能够有效抑制开关频率及其倍频附近的高次谐波幅值,从而大大减少逆变器驱动电机的电磁干扰。该文对混沌PWM逆变器输出电压的功率谱密度进行了分析,经过合理简化得到了混沌信号概率密度函数与逆变器输出电压功率谱密度之间的关系。根据功率谱密度的表达式,对比分析了概率分布不同的两种混沌序列(Logistic和Chua’s)对逆变器输出电压功率谱密度的影响。实验结果表明,采用混沌PWM调制可以有效抑制逆变器输出电压的高次谐波幅值,并且概率分布不同的2种混沌信号对PWM逆变器输出频谱的影响差别不大。

Analysis of Power Spectral Density of the Output Voltage in Chaotic PWM Inverter

Chaotic pulse width modulation(PWM)results in the reduction of the amplitude of harmonic in the switching frequencies,with advantageous effect on the suppression of the acoustic noise concentrated at specific tones in an inverter-driven electric machine.The power spectral density(PSD)of the output voltage of the inverter has been analyzed,and the relationship between the probability density function and the PSD of the output has been developed using some reasonable simplification.The effect of the chaotic signals(Logistic and Chua's)with different probability density on the output spectrum has been analysis contrastively according to the PSD expression.Experimental results show that the chaotic PWM can restrain the amplitude of the higher harmonic,and especially,chaotic signals with different probability density almost have the same affection on the output spectrum.