The Study Of The Cancellation Methods Of The Parasitic Capacitance Of Inductor

In the modern power electronic system, the inductor is widely used in the EMI circuit. The EMI filter can be used to cancel the noise signal or pass the useful signals in the EMI circuit. But for the structure reasons of the inductor windings, there is parasitic capacitance inside the inductor. The equivalent parasitic capacitance is in parallel with the inductor, and the parasitic capacitance will weaken the expression of the inductor in the EMI filter. The high frequency noise can not be cancelled greatly if the effect of the parasitic capacitance is great.In this dissertation, an equivalent cancellation capacitor is generated in parallel with the parasitic capacitor. The inductor is divided into two kinds. They are common mode inductor and differential mode inductor. The parasitic capacitance cancellation methods are different depend on the different structures of common mode inductor and differential mode inductor.The Multisim is used for the simulation of the practical inductor model with and without the parasitic capacitance cancellation. Based on the simulation model in Multisim, take some AC analysis on the loads of the model and get the Amplitude-Frequency curve and the Phase-Frequency curve.The simulation result shows that after the parasitic capacitance cancellation method form the dissertation, the effect of the parasitic capacitance can be cancelled.