Conducted EMI model for the low-voltage permanent magnet DC motor

The direct current motor with complex high-frequency impedance is difficult to model.In order to solve this problem,a simulation model of the direct current motor is established in this paper,and it can be used in the whole spectrum of the conducted electromagnetic interference(EMI).With the measured impedance spectrum characteristics,the circuit model which can evaluate the high frequency impedance characteristics accurately was established.Based on the mechanism of the motor transient voltage,the transient voltage pulse of motor ends was obtained by measuring.Then the conducted EMI model was established for the direct current motor.Simulation and experimental results show that their error is less than 1.5%,and the model is verified.This model is able to simulate the conducted EMI of the permanent magnet direct current motor in the frequencies band between 0.15 MHz and 108 MHz.It is commonality and can be also applied to analysis and prediction of the conducted EMI for the permanent magnet direct current motor.