9627323 Von Jouanne The general drive towards automated high efficiency and low cost control of ac motors has resulted in an increased application of solid state electronic Adjsutable Speed Drives (ASDs) in all levels of the power system. The recent advancements in power electronic devices have enabled high frequency switching operation and have improved the performance of pulse-width modulated (PWM) inverters for driving induction motors. In a typical ASD application a rectifier and a high frequency PWM inverter control both the voltage and frequency applied to the motor and thereby achieve variable speed operation over a wide range. High switching frequencies (2 to 20 kHz) are common with the present day insulated gate bipolar transistor (IGBT) technology for power levels over 200 kW. However, while the high switching speeds and advanced PWM switching schemes substantially improve the performance of the PWM inverter-fed induction motors, the associated high rate of voltage rise (dv/dt), of 0 to 600V in less than O.1 us, has adverse effects on the motor insulation, and can contribute to bearing and leakage currents. In response to these problems, the objective of this proposal is to analyze the effects of the application of ASDs on the operation of ac motors, investigate mitigation techniques and bring the results into the graduate and undergraduate power electronics curricula as appropriate. ***
