Design of Integrated CM Inductors on Both DC and AC Sides for DC-Fed Motor Drive Systems: Structure, Modeling, and Optimization Method

Regarding the filtering requirements on both sides of inverters, integrating the DC common mode (CM) inductor and AC CM inductor by coupling their magnetic path will reduce the overall size. In contrast to optimizing a discrete CM inductor, designing coupled CM inductors has to take more variables into consideration and to subject to more constraints, simultaneously. The coupled inductor must fulfill two requirements, namely satisfying the desired inductance value and avoiding saturation of cores. This paper proposed a volume optimization method to design coupled CM inductors under the combined constraints of inductance values and saturation issues based on the area-product method. Then, a coupled CM inductor structure and optimization procedures for its geometric parameters are highlighted. The optimization procedures first perform trial volume optimization using the basic modeling approach, followed by fine modeling simulations to identify the smallest volume inductor that meets the noise attenuation requirements. Finally, this optimization approach is experimentally verified. Moreover, the volume of the coupled inductor is reduced by about 10% compared with the similarly optimized discrete CM inductor.