Random swithing frequency pulse width modulation: Analysis, design and simulation

The traditional pulse-width modulation has been widely applied to the electronic and electric device in power system. However, the unexpected harmonics produce much electromagnetic noise which causes torque ripple, mechanical resonance and acoustic noise. By analyzing the harmonics theory of the traditional pulse-width modulation (PWM), a random switching frequency pulse-width modulation (RSFPWM) based on uniform distribution is designed in this paper. The simulation of the random switching frequency pulse-width modulation shows that the peaks of harmonics spectrum lines reduced and is more flattened than the traditional pulse-width modulation. And the simulations verified the validity and feasibility of the random switching frequency pulse-width modulation. The random switching frequency pulse-width modulation proposed in this paper elaborates the basic theory that is suitable for both AC and DC power supply.