基于SHEPWM调制策略的永磁同步电机三电平逆变器设计与实现

发布时间：2018-04-11 23:02

本文选题：三电平逆变器 + PMSM　；参考：《华侨大学》2016年硕士论文

【摘要】：三电平逆变器在高压大功率交流传动系统中有着广泛的应用,但是由于开关器件开关损耗以及散热的限制等因素,其最高开关频率一般只有几百赫兹,从而导致脉冲宽度调制(Pulse Width Modulation,PWM)波形中谐波含量大。同时,在高速列车牵引传动系统的整个速度范围内,载波比的变化范围非常大,如果只使用一种调制方式是无法满足调速的要求。为了解决这些问题,本文以三电平逆变器永磁同步电机为牵引电机,采用矢量控制技术,对特定次谐波消除脉冲宽度调制(Selective Harmonic Elimination of Pulse Width Modulation,SHEPWM)的多模式PWM策略进行研究,主要有以下内容:首先,基于两电平SHEPWM和三电平SHEPWM的数学模型,推导出非线性超越方程组,通过牛顿迭代法和差分演化算法得到解的曲线。在MATLAB仿真软件中对基于两电平逆变器和三电平逆变器的SHEPWM方法进行了对比分析,同时验证了SHEPWM消谐的效果,即N个开关角的SHEPWM可以消除N-1个谐波。然后,研究了采用多模式调制策略时,不同开关角的SHEPWM模式之间的平滑过渡,正弦脉冲宽度调制(Sinusoidal Pulse Width Modulation,SPWM)调制与SHEPWM之间的平滑过渡。并在MATLAB/Simulink中搭建基于SHEPWM的多模式调制仿真模型,通过采用三相同时切换与分别切换相结合的方法,减小了不同PWM策略间过渡时的电流冲击。最后,针对基于三电平逆变器的永磁同步电机控制系统设计了三电平变流柜和基于DSP+CPLD构架的硬件平台,并给出了控制算法实现的软件流程图。通过实验验证了主要外设设计的有效性,并对SHEPWM算法进行了验证,结果表明,硬件平台可以实现相应功能并已初步具备实现基于三电平逆变器的永磁同步电机多模式PWM算法的条件。
[Abstract]:Three-level inverter has been widely used in high-voltage and high-power AC drive systems. However, due to switching loss and heat dissipation of switching devices, the maximum switching frequency is generally only a few hundred hertz.Therefore, the harmonic content in pulse Width Modulation (PWM) waveform is large.At the same time, in the whole speed range of traction transmission system of high-speed train, the range of carrier ratio variation is very large, if only one modulation mode is used, it can not meet the requirements of speed regulation.In order to solve these problems, this paper studies the multi-mode PWM strategy of selective Harmonic Elimination of Pulse Width Modulation (SHEPWM) with three-level inverter permanent magnet synchronous motor (PMSM) as traction motor and vector control technology.The main contents are as follows: firstly, based on the mathematical models of two-level SHEPWM and three-level SHEPWM, the nonlinear transcendental equations are derived, and the curves of the solutions are obtained by Newton iterative method and differential evolution algorithm.In the MATLAB simulation software, the SHEPWM method based on two-level inverter and three-level inverter is compared and analyzed, and the effect of SHEPWM harmonic elimination is verified, that is, the SHEPWM with N switching angles can eliminate N-1 harmonics.Then, the smooth transition between SHEPWM modes with different switching angles, and the smooth transition between sinusoidal Pulse Width modulation and SHEPWM are studied.The simulation model of multi-mode modulation based on SHEPWM is built in MATLAB/Simulink. The method of three-phase simultaneous switching and separate switching is used to reduce the current impulse during the transition between different PWM strategies.Finally, the three-level converter cabinet and the hardware platform based on DSP CPLD are designed for the permanent magnet synchronous motor control system based on three-level inverter, and the software flow chart of the control algorithm is given.The effectiveness of the main peripheral designs is verified by experiments, and the SHEPWM algorithm is verified. The results show that,The hardware platform can realize the corresponding function and has the condition to realize the multi-mode PWM algorithm of permanent magnet synchronous motor based on three-level inverter.
【学位授予单位】：华侨大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM464;TM341

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