Electric machine drive design improvements through control and digital signal processing techniques

Abstract

Developing the control algorithms of electric machine drives for less noise and harmonics is proposed here for design improvements. Modern control algorithms for electric machine drives are implemented and their radiated magnetic fields are measured and imported into a digital signal processing unit. The measurement was implemented using magnetic field antennas which cover low frequencies. A digital signal processing unit was designed for online and real-time measurement and processing of the fields and categorizing the harmonics. The controller compares the desired and measured signals and modifies the duty cycle of the switches to suppress the existing harmonics. The manual and automatic suppressions of some critical harmonics were implemented in two switching techniques using a defined procedure. Consequently, the modified control algorithm of the drive would radiate the electromagnetic stray field with less noise and harmonics. This lead to lower electromagnetic interference (EMI) from the machine drive. Since there is no need to locate any sensor inside the machine or the converter, this can be considered as a nondestructive method for industry implementations, where it's impossible to access the parameters of components for online monitoring.