Voltage Overshoots Mitigation in a Long Cable PWM-Fed Induction Machine Using dv/dt Filters

Significant voltage overshoots are observed in the input terminals of long cable pulse-width modulation (PWM)-fed induction machines, which can detrimentally impact the machine’s lifespan and performance. To mitigate this concerning phenomenon, dv/dt filters consisting of R, L, and C elements are used in the circuit. In this paper, the high-frequency model of a long cable PWM-fed induction machine is established, incorporating the high-frequency models of the machine and long cable, as well as the pulses generated by the PWM converter and filters. Differential mode and common mode impedance measurements are employed to develop the high-frequency model of the induction machine, while short circuit and open circuit impedance tests are conducted to establish the high-frequency models of the long cable. The transmission line modeling approach is then utilized to incorporate the high-frequency modeled machine and long cable, enabling the prediction of voltage overshoots at the machine’s terminal. Three distinct dv/dt filters are placed at the beginning, middle, and end of the long cable to mitigate the voltage overshoots in the terminal of the PWM-fed induction machine. Test results are presented for a 100 m cable, 2 hp machine fed by a PWM converter in the presence of the dv/dt filters, aiming to identify the appropriate filter location for minimizing voltage overshoots in the terminals of the machine.