Optimization of switching frequencies in the limited-pool randomspace vector PWM strategy for inverter-fed drives

A space vector PWM technique for inverter fed AC drives which, in contrast with known random modulation methods, is characterized by a very small pool of randomly used switching frequencies, is presented. The limited size of the pool facilitates design of digitally implemented subsystems of the drive, whose settings depend on the length of sampling interval. A method for optimal selection of pool frequencies is described and validated by experimental evidence, including EMI measurements.