Performance improvement based on adaptive commutation strategy for switched reluctance motors using direct torque control

Abstract

This research presents an improved direct instantaneous torque controller (DITC) for switched reluctance motors (SRMs). It incorporates a novel adaptive real-time commutation mechanism. The proposed method can effectively enhance the torque profile and efficiency of the machine by proper real-time adjustment of both the turn-on and the turn-off angles. First, an initial value of the turn-on angle is selected to achieve the highest torque generation capability. Then, with a real-time adjustment around the pre-selected initial angle, the instantaneous torque error can be further compensated. Hence, the torque ripple is minimized.Regarding the turn-off angle, an initial value is selected to satisfy the minimum required conduction angle of SRM. Then, this value is continuously adjusted at each electrical cycle by utilizing a phase current detector to force the outgoing phase current to decay to a less effective value before the negative slope of the inductance profile. Therefore, this prevents serious negative torque generation. The proposed strategy fully utilizes the torque generation capability of the motor with a minimized torque ripple, besides the phase currents, are generated in optimal conduction range to enhance the motor efficiency. The simulations and experiments have been carried out on a 3-phase 750 W 12/8 SRM to validate the proposed method's feasibility and effectiveness.

Keywords

• Switched Reluctance Motors
• Direct Torque Control
• Torque Profile Improvement
• Adaptive Commutation