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.