【作者】 孙敬伟；

【导师】 郑黎明；

【作者基本信息】 汕头大学 ， 机械电子工程， 2008， 硕士

【摘要】 本论文以交流调速中的脉宽调制技术(PWM)为研究对象,找出两电平的空间矢量调制(SVPWM)的改进方法—混合空间脉宽调制(Hybrid SVPWM),并和普通的空间矢量调制进行对比分析其优点。详细论述了三电平逆变器结构、原理和空间矢量调制法,进而探讨了其对永磁同步电机直接转矩控制技术(DTC)控制的实现方法,并且利用Matlab/Simulink工具对控制系统进行建模与仿真,得到了和理论分析一致的仿真结果。最后利用反步法实现对永磁同步电机的位置控制,得到了满意的结果。论文首先分析了永磁同步电动机的结构和数学模型,通过坐标变换的方法简化电机模型,得到电机的电压、磁链和转矩方程。初步介绍PWM的原理、采样方法以及空间矢量脉宽调制法,在其基础上引入磁链均方根波动(RMS)的分析方法,通过调整各矢量的换向序列,通过细化扇区的方法,在不同区域选择不同的逆变器换向序列,从而实现减少波形脉动的目的,这种方法即为混合空间矢量调制(Hybrid SVPWM)。通过仿真和快速傅立叶分析(FFT)可知,该方法有效减少了电流的谐波分量,提高了控制的精度。接着在两电平逆变器的基础上研究三电平逆变器的拓扑结构和工作原理,以及如何实现空间脉宽调制的方法。接着分析了永磁同步电机的直接转矩原理,找出将三电平逆变器的SVPWM和直接转矩结合的方法,借助Matlab/Simulink工具,对其系统的各环节进行仿真建模。通过和两电平逆变器的直接转矩进行对比,证明了三电平逆变器的控制效果好于两电平。最后分析了一种非线性控制方法:反步法(Backstepping),结合永磁同步电机的数学模型,实现反步法的控制作用,通过仿真验证了该方法的可行性。更多还原

【Abstract】 The PWM of ac speed regulating is researched in this paper. The method of Hybrid SVPWM- the way of improving the two-level SVPWM is used, through comparing with the normal SVPWM in order to show its advantages. The structure , principle and SVPWM of three-level inverter is discussed in detailed, and the implementation method of combining it with the DTC control of PMSM is analyzed. A simulation model of control system is given based on Matlab/Simulink, whose simulation result is consistent with the analysis of theory. At last the method of backstepping is used in the position control of PMSM, whose result is satisfied.Firstly, the structure and the mathematics models of PMSM are analyzed in the paper, and the motor model is simplified through introducing the various coordinate, and then the voltage, flux and torque equations of the motor are got. The principle of PWM and SVPWM is analyzed, on the basis of which the RMS method analysis of flux linkage is introduced, and the paper find a better way to subdivide the sector through the change of the sequences of vectors, which is method Hybrid SVPWM. We can find that this method reduces the harmonic component of current by analyzing the result of simulation and FFT.Secondly, the topology and operation principle of three-level inverter is researched on the basis of two-level inverter, and the method to achieve its SVPWM is carried out. Then analyze the principle of the DTC of PMSM, and further find a way to combine the SVPWM of three-level with DTC, and set up the sub-modules of PMSM DTC system by Matlab/Simulink. And the simulation results show the method is successful, proving the better control effect of three-level inverter than the two-level.Thirdly, Backstepping-a motor nonlinear control method is analyzed, and the control method of backstepping is realized by combination with the mathematics model of PMSM. At last verify the feasibility of this method through the simulation.更多还原