The worst-case output harmonic content of a AC PWM auxiliary power source

A method of predicting the worst-case harmonic content of the output of a static PWM 400 Hz auxiliary power source is presented for each of the three major choices of power switching semiconductors: HEXFET, IGBT, and bipolar. The harmonics were calculated using a C language computer routine written for this purpose, and the tabulation printed out to the 27th harmonic is given. It is shown that the output waveform quality is strongly dependent on the switching parameters of the device used and the choice of carrier frequency.<>