Simulation-based exploration of aliasing effects in PWM power converters

Aliasing effects in pulse-width-modulated power converters are explored by first using switched-circuit simulation to generate circuit waveforms and then analyzing their spectral content using FFTs. The results for a basic PWM boost converter running open-loop under voltage-mode control show that perturbing the control signal or input voltage at frequencies close to the switching frequency or its harmonics can give rise to significant aliased components at the low difference frequency. The simulation results reinforce the concerns raised in regarding the limitations of small-signal frequency-response information in frequency ranges where aliasing is significant. The key steps in analyzing the observed simulation results is also presented.