Common-Mode Noise Reduction by Parasitic Capacitance Cancellation in the Three-Phase Inverter

Electromagnetic interference (EMI) has drawn great attention in recent years. In this particular case, it is generated by the three-phase inverters in power electronics applications due to the power devices turning on and off at high frequency. In this paper, in order to alleviate such EMI noise, a high-frequency common-mode (CM) equivalent model is developed, which leverages the effect of parasitic parameters. Meanwhile, in order to eliminate the effect of the parasitic capacitance between the phase node and ground, which is the cause of main CM noise propagation, a coupled inductor connected with a capacitor circuit, which is equivalent to a negative capacitance is proposed. The parameter calculation for the passive negative capacitance circuit is given in detail. The experimental results demonstrated the effectiveness of the circuitry structure and its ability to reduce CM noise.