Analysis and simulation of common-mode conducted interference source in separately excited DC motor

Direct current(DC) motors are power core of electric industrial trucks, such as forklift and van. But they have become the serious inner interference source because its structure and control has changed significantly. For example, the steering process and the unstable touch between brush and commutator will generate transient voltage. These transient voltage will invade into other component as conducted interference. This paper took the XQ-7A2 separately excited DC motor produced by Liaoning Motor Maker as example and analyzed principle of interference source and coupled path in DC motor to build up its interference source model with simulation software MATLAB and PSPICE. At last, we conducted experiment to verify this interference source model with the aid of linear impedance stabilizing network (LISN). Experiment and simulation validated the result that touch voltage in the steering process was serious interference source in DC motors. This interference source model laid a good groundwork for foundation of high frequency interference model of DC motor drive controller system.