Optimal filter tuning to minimize the transient overvoltages on machine windings fed by PWM inverters

Modern Pulse Width Modulation (PWM) inverter output voltage produces electrical stresses on the windings of induction machines due to fast rise times. The feeder cable of this type of arrangement produces additional stresses on the windings. This paper proposes an optimized filtering technique to mitigate the transient overvoltages and reduce the associated stresses. Multi-objective optimization algorithms are used to find the parameters of an RLC filter that minimizes the objective functions (rise time, setting time, and over shoot) in the output voltage. For that purpose, a non-uniform transmission line model of the machine winding is used to predict the transient voltage propagation along the machine winding. The winding parameters are computed using the finite element method. The feeder cable is included by means of a distributed parameter model whose parameters are obtained from measurements. The simulation results are validated by means of measurements on an experimental cable-coil setup. Finally, the optimal filter obtained from simulations is physically constructed to test its performance on the experimental coil.