A chirp PWM scheme for brushless DC motor drives

Abstract

A novel chirp pulse width modulation (CPWM) scheme is proposed to improve the performance of AC motor drives by reducing electromagnetic interference. The proposed CPWM is operated on the chirped waveform that has a specified bandwidth defined within a minimum and a maximum switching frequency. The design procedure of CPWM that includes selecting the chirp bandwidth and the PWM frequency sweeping time period is presented and analyzed. Then the theoretical analysis is done for both the chirped and non-chirped waveforms. Optimum EMI reduction scheme is developed from the theory. The computer simulation and experimental results verify that the proposed CPWM method has better performance in comparison to PWM with fixed frequency.Index Terms -Chirp pulse width modulation (CPWM), electromagnetic interference (EMI), Brushless DC drives, frequency dithering.

A Novel Controlled Frequency Band Impedance Measurement Approach for Single-Phase Railway Traction Power System

“…As a novel PWM scheme, the chirp-PWM proposed in [28] has various switching frequencies with a chirp feature instead of fixing (as in [27]) or randomizing (as in [18]) the switching frequencies for the classical PWM scheme. To adapt the aforementioned linear chirp signal y chirp (t) to PWM-type (i.e., chirp-PWM) signal, an effective converting scheme y chirp − PW M (t) can be actualized as…”