中低速开关磁阻电机转矩优化策略研究
Torque Optimization of Medium？？Low Speed Switched Reluctance Motors

为解决开关磁阻电机因其双凸极结构和严重非线性电感特性所导致的在换相和单相导通时转矩脉动较大的问题,提出了以转速、转矩和电流为控制量的模糊滑模多重闭环控制策略。速度环采用模糊滑模控制,通过积分变换将转速差转化为给定转矩,通过比较电机瞬时转矩与给定转矩,控制开关管的导通关断,实现转矩闭环控制;在电机换相时对同时导通的两相绕组进行转矩分配,建立转矩、电流和转子位置角的解析式,由分配的转矩求得给定的绕组电流进行电流闭环控制,从而达到对电机换相和单相导通时转矩脉动的有效抑制。仿真试验结果表明:在电机中、低速运行时,该控制系统与PID控制下的直接瞬时转矩控制(DITC)系统相比控制效果更好;电机低速运行时转矩波动稳定在±0.3 N？m以内,中速运行时转矩波动稍有增大,但仍维持在±0.8 N？m以内,实现了对转矩脉动的有效抑制。
Switched reluctance motor with double salient structure and nonlinear inductance characteristics may be subject to torque ripple when working in the states of switching and single？？phase conducting. In view of this, a fuzzy sliding？？mode multiplex？？loop control system with control quantities of speed, torque and current is designed, in which fuzzy sliding？？mode control is adopted for speed loop and the speed difference is transformed into given torque through integral transformation. By comparing instantaneous torque with the given torque, switching tubes will be controlled to realize torque’s closed？？loop control. The torque is distributed to the windings of two simultaneously conducted phases during the commutation of motor and the equations of torque, current and rotor position angle are established. The winding currents will be obtained via the distributed torque to realize current’s closed？？loop control. Therefore, the torque ripple can be depressed effectively during the commutation and single？？phase conducting. Simulation and experimental results show that the proposed method has a better control effect than the direct instantaneous torque control (DITC) with PID at low speeds, and the torque ripple can be stabilized within ±0.3 N？m, while becoming slight greater at medium speeds but within the range of ±0.8 N？m. So the torque ripple is depressed effectively by the proposed method