Optimal Current Control of Switched Reluctance Motors Over the Entire Operating Range

Controlling Switched Reluctance Motors (SRMs) requires careful selection of conduction angles to ensure optimal performance under various operating conditions. At low speeds, hysteresis control can provide the required torque by selecting the appropriate current reference. However, torque quality and efficiency can be further improved by selecting the right conduction angles. In contrast, conduction angles are the only control parameters at high speeds since peak current control is impossible. Hence, choosing the right conduction angles can significantly impact the average torque, torque ripple, and the RMS value of phase current, loss, and efficiency. This paper discusses the effects of turn-on and turn-off angles on average torque, torque ripple, and Integral Time Absolute Error (ITAE). Genetic Algorithm (GA) is used to find optimized firing angles, and the objective function for optimization is maximizing the average torque. The paper proposes a comprehensive approach to automatically control the conduction angles that excite SRMs at variable speeds, reference currents, and DC-link voltages. The results of the simulation demonstrate the efficacy of this method. Furthermore, the proposed controls are evaluated in a three-phase 12/8 SRM compared to a conventional controller. This controller is particularly suitable for transportation applications, especially for traction and propulsion in vehicles, due to its high average torque, low torque ripple, and fast dynamic response across various operating points.