A Method for Compensating Wave Reflections in Transmission Lines
This technology is a method to eliminate voltage overshoot in cables used to connect AC electric motors and pulse width modulation (PWM) inverters. As a function of cable length and voltage rise time, voltage overshoot occurs when high frequency currents reflect between the motor and source ends of a cable. University of Illinois researchers have devised a compensator that shapes the output of the PWM inverter in order to eliminate these reflections; the method only requires knowledge of the transmission line characteristic impedance and propagation delay. This technique extends the life of motor insulation and protects voltage-sensitive devices.