多相永磁同步电机多维优化矢量控制

针对传统直接转矩控制运行时存在逆变器开关频率不恒定、转矩脉动大的问题，从六相电机空间矢量解耦特点入手，提出了一种转子磁链闭环的六相感应电机反推式空间矢量调制与直接转矩控制（space vector modulation and direct torque control，SVM-DTC）方法.首先，分析和建立了六相电机数学模型，并运用新虚拟电压平衡矢量来确定空间电压矢量脉宽调制（space voltage vector pulse width modulation，SVPWM）方案以便减小电机定子谐波电流；其次，应用反推算法设计转速反推控制器替代传统直接转矩控制中的转速PI控制器，应用转矩反推控制器与磁链反推控制器得到静止坐标系下的定子电压实际分量；最后，在Matlab/Simulink中进行系统的仿真验证.通过仿真与PI控制的改进DTC方法相对比可知，该控制方案下电机具有响应速度快、转矩脉动小、可调参数少和可改善定子电流波形等优点，并使逆变器工作在恒定开关频率下.

Multi-dimensional optimal vector control of multi-phase permanent magnet synchronous motors

To solve the problems of non-constant switching frequency and big torque ripple in traditional direct torque control(DTC), considering the characteristics of space vector decoupling of the six-phase motor, a novel backstepping SVM-DTC of six-phase induction motor based on rotor flux closed-loop was proposed. Firstly, the mathematical model of motors was built, and the new virtual voltage balance vector was used to determine the space voltage vector pulse width modulation (SVPWM), in order to reduce the motor stator harmonic current. Furthermore, the backstepping principle was applied that aspeed backstepping controller was used to replace a PI controller in traditional DTC. A torque and flux backstepping controller was designed to gain stator voltage. Finally, the system was verified by simulation in Matlab/Simulink. At the same time, the modified DTC was compared based on PI control, and the result shows that the proposed strategy has rapid response, low torque ripple, a few adjusted parameters, and the stator current waveform is improved and make inverters have constant switching frequency.