A simulation model for the performance prediction of brushless DC drives is used to investigate the high-speed torque performance for a motor switched by a PWM inverter. The solution is given for both 120 degrees and 180 degrees conduction angles of inverter operation, with provision for selecting the advance commutation angle. The influence of the more important drive parameters on high-speed performance is described. The paper also presents two simplified analytical approaches for obtaining the optimum phase-advance angle in the high-speed ranges. The merit of these methods, compared with trial-and-error based on simulation, is described.