基于改进SVPWM永磁直线同步电机直接推力控制

Direct thrust control of permanent magnet linear synchronous motor based on modified SVPWM

针对传统空间矢量脉宽调制(SVPWM)永磁直线同步电机直接推力控制系统响应慢、逆变器开关损耗大、输出电流谐波含量高、系统效率低、推力脉动大的问题,建立了逆变器损耗模型,推导出损耗以及谐波含量关系式,得出损耗和谐波含量最小时的零矢量最优分配方式,提出最小损耗SVPWM方法,并采用定子电流最小控制代替系统定子磁链给定值.通过Matlab/Simulink仿真实验比较了传统方法和本方法在不同速度时加载不同负载的系统损耗和效率以及在电机起动和突加负载时系统的响应能力和推力脉动,并分析了两种方法的逆变器输出电流谐波含量,证明了本方法的有效性与可行性.

In order to solve the problems that for the direct thrust control （DTC） system of permanent magnet linear synchronous motor （PMLSM） based on the conventional SVPWM, its response is slow, the loss of inverter switch is large, the harmonic content of output current is high, the efficiency of the system is low and the thrust ripple is large, the loss model for the inverter was established, and the relationship between the loss and harmonic content was derived. The optimal distribution mode for the zero vector was obtained when the loss and harmonic content were minimum, and the minimum loss SVPWM method was proposed. In addition, the stator current minimum control was used to replace the given values of stator flux. Through the Matlab! Simulink simulation experiment, the loss and efficiency of the system under different speed and load as well as the response capability and thrust ripple when the motor was started or a sudden load was added with the conventional and proposed methods were compared. Moreover, the harmonic content of inverter output current with two methods was analyzed. The effectiveness and feasibility of the proposed method get proved.