A new SVPWM-based control scheme of permanent magnetic brushless DC machine with trapezoidal back EMF waveforms

Compared to permanent magnetic brushless DC machine with trapezoidal back EMF waveforms (BLDCM), permanent magnetic synchronous machine with sinusoidal back EMF waveforms (PMSM) has superior performance. To enhance performances of BLDCM, this paper adopts a new type oriented vector control strategy. Contrary to traditional rotor-flux oriented vector control in PMSM, the new control strategy takes back EMF as the oriented vector for improving the capability of maximum torque per ampere (MTPA) of BLDCM and reducing the torque ripple [1]. Also, a Space vector PWM modulation (SVPWM) based on “120° conduction mode” is utilized for three-phase bridge inverter [2]. Combined the oriented strategy aforementioned with proposed SVPWM method, a new control system is constructed. Simulation validates effectiveness of this new control scheme.