A critical assessment of the implementation of PWM techniques in switchmode magnet power supplies

The characteristics of a carrier-based pulse-width modulator under different modulation techniques are evaluated in this paper. Modulation with the most commonly used carrier waveforms (triangular and sawtooth waveforms) and sampling methods (uniform, double and natural sampling) is studied. In each case, the switching harmonics at the modulator output are calculated and the frequency response of the modulator is determined. Different modulation techniques are then compared, and the one that best suits switchmode magnet power supply applications is identified.