A Method for the Parameter Identification of an AC Motor High-Frequency Model Based on the Exchange Market Algorithm

The use of wide bandgap semiconductor devices, such as SiC and GaN MOSFETs, in high-frequency converters introduces new challenges for the design of electric drives. The very fast switching transient of which these devices are capable, in fact, can become a serious threat for the reliability of the entire system. Electromagnetic interferences due to the high dv/dt and di/dt, voltage reflections along the cable that cause overvoltage and ringing at the motor terminals, and large common-mode voltages that produce current circulation in the motor bearings are recognized as the major phenomena leading to premature failure of the drive. It is therefore important for designers to approach the problem from a system point of view, having the possibility to accurately model the system in the high frequency domain to take appropriate measures to increase reliability. In this paper, an automated fitting procedure is proposed to identify one of the most accurate high-frequency models of an induction machine. The procedure relies on the experimental measurement of the differential, common-mode and parasitic impedance of the tested machine and adopts Exchange Market optimization algorithm to search for the best approximation of the three measured impedances. Implementation issues and advantages are presented and discussed.