Active motor terminal overvoltage mitigation method for parallel voltage source inverters

Electrical motor fed by voltage source inverters has been known to face transient overvoltage problems caused by the inverter switching operations. With the parallel inverter topology and with the modulation strategy presented in this study, the motor terminal overvoltage can be reduced without any passive filtering. The parallel inverter topology has individual motor leads from each inverter connected at the motor terminals. Modulation strategy for any number of parallel inverters with current balancing is presented. Experimental results are presented for two and three parallel standard industry frequency converters to verify the method.