Energy Efficiency Improvement for an Electric Vehicle PM BLDC Propulsion System Using Phase Advance and Dwell Control

- Improving the propulsion system used in mobility applications remains a challenge for performant electric motors such as PM BLDC (Permanent Magnets Brushless DC motors). Their traction characteristic recommends them for EVs (Electric Vehicles), providing high power density and starting torque. The application of flux weakening techniques is not possible for such motors and other techniques are necessary. The actual paper presents the usage of PA (Phase Advance) and DC (Dwell Control) in a new perspective, not only for operational area extension but especially for efficiency improvement and the reduction of the electric energy consumption on EVs. With PA, the opening of commutation transistors sooner, before the trapezoidal back EMF (Electromotive Force) attempts the maximum value, increases the voltage applied on the phase terminals of the motor phase. In parallel, the blocking of the transistors is delayed using the DC technique. The phase current increases faster and the electromagnetic torque increases. Under MATLAB-Simulink, a speed-controlled motor allows for determining the pairs of PA and DC angles maximizing the energetic efficiency of the EV powertrain using two motors. By submitting the EV to a normalized testing cycle the application of the method confirms the powertrain capabilities to cover the request reducing the electric energy consumption.