一种改进的四相开关磁阻电机直接转矩控制策略研究

Improved direct torque control strategy of four-phase switched reluctance motor

针对开关磁阻电机转矩脉动大、启动时转子震荡的问题,将改进磁链估算模型和PWM技术应用到开关磁阻电机的直接转矩控制策略中。对四相开关磁阻电机的直接转矩控制策略进行了研究,设计了合适的磁链模型和开关表,分析了电机启动时转子震荡的原因,设计了参考转速变化的磁链估算模型;将PWM技术和直接转矩控制策略结合起来,提出了通过占空比调节控制周期内等效电压的大小,进而控制转矩改变量大小的方法;在Matlab/Simulink平台上,对优化前后电机的启动性能和转矩脉动抑制效果进行了仿真分析。研究结果表明:加入改进磁链估算模型后,有效解决了启动时转子震荡的问题,提高了启动转矩;引入PWM的开关磁阻电机直接转矩控制策略具有更好的转矩脉动抑制效果。

In order to solve the problem of large torque ripple and rotor vibration,a direct torque control strategy of four-phase switched reluctance motor was proposed,which was based on PWM and the improved flux model. The improved flux model and switching table,combined with the characteristics of four-phase switched reluctance motor,was designed to realize the direct torque control strategy of four-phase switched reluctance motor,which solves the problem of rotor turbulence when motor start. The PWM module was introduced into the direct torque control strategy to regulate the torque more subtly,by changing the equivalent voltage. The starting performance and torque ripple suppression effect of motor before and after optimization were simulated and compared,under Matlab/Simulink environment. The results indicate that the problem of rotor vibration during start-up is solved effectively meanwhile the starting torque is improved after applicating the improved flux model,and direct torque control strategy of switched reluctance motor with PWM has better torque ripple control effect.