A study on the effect of DC-link decoupling capacitors

The main function of the DC-link decoupling capacitors, integrated between the voltage source and the power devices, is to suppress the effect of the parasitic inductors and minimize the voltage overshoot. Besides, decoupling capacitors can also affect the electromagnetic interference frequency spectra. In this paper, the effects of decoupling capacitors are explained from the time-domain and the frequency-domain. The decoupling capacitance selection strategy is proposed according to the analysis.