Torque ripples enhancement of a PMBLDC motor propelled through quadratic DC–DC boost converter at varying load

Abstract

The characteristic effects of a permanent magnet brushless dc (PMBLDC) motor which is propelled by a quadratic DC–DC boost converter was investigated in this paper. The boost converter applied inductor coupling with semi-conductor switches which operate concurrently to produce a high conversion voltage ratio. Modeling of the PMBLDC motor was presented while simulation was performed using a closed loop control system with different controllers for the enhancement of torque–speed performance at varied load. Simulation results show that an optimum voltage gain with minimum voltage stress was achieved at 0.9 duty cycle while varying the inductor turns ratio (n) from 1 to 6 and inductor coupling coefficient (K) from 0.1 to 1.0 so as to ensure that the entire flux generated in one coil is fully linked to the other. A simplified PI controller was designed and experimented through simulation for excellent drive performance at varying load. The results from the spectral display show that the usual speed oscillation and torque ripples produced by the machine were attenuated using different speed controllers. The Total Harmonic Distortion (THD) values indicate that the PID controller achieved a minimal value of 24.06% for speed and 23.16% for torque as compared to 28.73% and 29.82% obtained from the PI controller, while the P controller achieved 41.88% and 35.67% as shown in the graphical abstract.