基于双三电平逆变器的开绕组PMSM直接转矩控制系统

发布时间：2018-04-24 09:04

本文选题：开绕组 + PMSM　；参考：《中国矿业大学》2017年硕士论文

【摘要】：双三电平逆变器系统因为其较高的输出和容错性能成为近年来研究的焦点。双逆变器拓扑包含的开关状态组合繁多,有利于调制策略的灵活选择,但同时也增加了策略的计算难度。当系统中双逆变器采用共母线并联结构时,具有成本低、更易实现四象限运行等优点,但是零序电压的存在也会制约电机控制系统的输出性能。针对调制策略复杂度高的问题,本文提出了一种新型的双三电平逆变器简化调制策略,该策略无需进行扇区判断和矢量作用时间计算,通过三相输入电压直接计算占空比,再由占空比得到对应的输出开关状态,能够大大的简化计算过程。另外还对该算法造成中点电位波动进行了抑制。针对共母线结构的双逆变器系统中存在共模电压的问题,本文分析了其形成的原因,并提出了一种基于零共模矢量的双三电平逆变器简化调制算法,保证在完全抑制共模电压和零序电压的同时,兼顾对算法复杂度的优化。为了分析采用零共模矢量调制后双逆变器输出性能变化,本文以开绕组永磁同步电机控制为应用背景,建立精确的数学模型,在此基础上分别采用零共模电压矢量和标准矢量两种调制策略实现电机的直接转矩控制,并在Simulink下进行了仿真实验。仿真结果表明,采用零共模矢量的调制算法能够对因绕组中性点拆开后绕组中无法抵消的谐波成分有较好的抑制作用。
[Abstract]:Due to its high output and fault-tolerant performance, dual-three-level inverter system has become the focus of research in recent years. The dual-inverter topology includes a variety of switching state combinations, which is conducive to the flexible selection of modulation strategies, but also increases the difficulty of calculating the strategies. When the dual inverter adopts the common bus parallel structure, it has the advantages of low cost and easy to realize the four-quadrant operation, but the existence of zero-sequence voltage will also restrict the output performance of the motor control system. In order to solve the problem of high complexity of modulation strategy, this paper proposes a novel simplified modulation strategy for two-level three-level inverter. This strategy does not need sector judgment and vector action time calculation, and directly calculates the duty cycle by three-phase input voltage. Then the corresponding output switching state can be obtained by duty cycle, which can greatly simplify the calculation process. In addition, the midpoint potential fluctuation caused by this algorithm is also suppressed. In order to solve the problem of common mode voltage in a common-bus inverter system, this paper analyzes the reasons for its formation, and proposes a simplified modulation algorithm for dual-three-level inverter based on zero common-mode vector. It is guaranteed that the common mode voltage and zero sequence voltage are completely suppressed while the complexity of the algorithm is optimized. In order to analyze the change of output performance of double inverter with zero common-mode vector modulation, this paper takes open-winding permanent magnet synchronous motor control as the application background, and establishes an accurate mathematical model. On this basis, two modulation strategies, zero common-mode voltage vector and standard vector, are used to realize the direct torque control of the motor, and the simulation experiments are carried out under Simulink. The simulation results show that the modulation algorithm with zero common-mode vector can restrain the harmonic components in the winding which can not be offset after the neutral point of the winding is removed.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM464;TP273;TM341

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