PWM sinusoidal inverter with modulation switching and carrier frequency modulation

This paper discusses basic characteristics of the pulse width modulation (PWM) sinusoidal inverter achieved by means of modulation switching operations. The considered PWM is to repeat the operation of leading and trailing edge modulation at each peak of a reference sinusoidal signal. The method has characteristics that undesirable lower harmonic components distributed around a carrier frequency β are decreased. It is possible as a result to produce an (N+1)-level PWM sinusoidal inverter with a distortion rate of 0.3% or less and the maximum operating angular frequency Nβ/4. Furthermore, by adding a carrier frequency modulation, a high-frequency sinusoidal inverter which operates at Nβ/2 π[Hz] is developed.