Magnetic force in three phase induction motor driven by ultrasonic carrier frequency sinusoidal PWM inverter

A method is described for measuring the magnetic force in a three-phase induction motor driven by a 20 kHz-carrier sinusoidal pulsewidth-modulated (PWM) inverter, and the experimental results are presented. The force is measured by using 36 flux-detecting coils fitted around all the stator teeth. The voltage v(n,t) induced in the coils is sampled with a frequency of 100 kHz. The frequency and mode of the magnetic force are analyzed by a fast Fourier transform approach. The vibration and acoustic noise of a motor driven by a 20 kHz-carrier sinusoidal PWM inverter are examined and compared with those of the motor driven by a conventional inverter.<>