Research on Modeling Method of Conducted Emissions Simulation for DC Brush Motors 2020-01-1372

The conducted emissions of DC motors have been a very important content when testing electromagnetic noise. It has certain practical guiding significance to optimize and improve the motor in the design stage through the simulation of conducted emissions circuit level. The existing literature research shows that the simulation results can not reflect the test results of the conducted emissions of the motor well because it is difficult to accurately model the armature winding and the commutation process of the motor in the electromagnetic simulation of the conducted emissions circuit level of the DC brush motor. In this paper, an electromagnetic simulation modeling method for conducted emissions of DC motor is proposed. The circuit model established in the PSPICE can simulate the actual conducted emissions values of DC motor by the method. Firstly, an impedance analyzer is used to test the impedance of a certain type of windowed DC brush motor, and the impedance spectrum of the coil winding is obtained. A second-order LC circuit model is established in PSPICE and fitted with the measured coil winding impedance. Secondly, the commutation time is calculated by the motor parameters, and an accurate model of the motor commutation process is established in PSPICE. Finally, the time domain variation of the voltage across the 50 ohm resistor in the LISN is obtained by the voltage probe, and the voltage data is subjected to Fourier operation to obtain the conducted emissions spectrum of the motor. By comparing the simulation with the test results, it can be considered that the electromagnetic simulation model established by the modeling method used in this paper can simulate the actual test results of the conducted emissions of the motor, which has a good practical reference value for the motor design stage.