Improved Efficiency Optimization Control of SRM Based on Redefined Optimal Turn-On Angle and Its Corresponding Analytical Formula

The function analysis method based on the optimal turn-<sc>on</sc> angle is one of the most popular efficiency optimization control strategies for switched reluctance motor (SRM) system, but it still has certain shortcomings. Under certain conditions, the optimal turn-<sc>on</sc> angle proposed by existing research is available, but its analytical formula has either low accuracy or complex solution. In addition, when the operating condition is changed, resulting in the rising rate of the phase flux-linkage at full-voltage is less than the slope of the reference flux-linkage at θ_m, the optimal turn-<sc>on</sc> angle proposed by the existing research will be unavailable. Hence, to solve these issues, this article presents an improved efficiency optimization control method of SRM based on a redefined optimal turn-<sc>on</sc> angle and its corresponding analytical formula. Based on the flux-linkage analysis, the SRM system is divided into two modes according to different operating conditions, with each mode corresponding to different optimal turn-<sc>on</sc> angles. In mode Ⅰ, the optimal turn-<sc>on</sc> angle proposed by the existing research is available and still in used. And this article presents a new analytical formula for this optimal turn-<sc>on</sc> angle, which has high accuracy, convenient solution, and simple structural form compared to the existing analytical formulas. In mode Ⅱ, the existing optimal turn-<sc>on</sc> angle is unavailable. Thus, this article redefines a new optimal turn-<sc>on</sc> angle in mode II and also presents its corresponding analytical formula. The analytical formulas for the two modes are similar in form and both are deduced based on the flux-linkage calculation. The simulations and experiments are conducted to verify the effectiveness of the proposed efficiency optimization control strategy.