【作者】 李山；

【导师】 王明渝；

【作者基本信息】 重庆大学 ， 电气工程， 2009， 博士

【摘要】 与三相电机驱动系统相比,多相电机驱动系统在大功率、高可靠性和低直流电压供电应用场合具有明显优势,然而,作为一种新技术,多相电机的控制在理论和实践中依然存在着大量值得研究和探讨的问题,本文对多相电机的理论、SVPWM控制技术、直接转矩控制技术和缺相运行的控制技术进行了全面深入的研究。论文首先分析了多相感应电机的绕组结构,利用空间矢量解耦的方法,将多相电机从m维空间解耦至若干个相互垂直的谐波子空间,建立了多相感应电机谐波基下的数学模型。同时分析了多相感应电机逆变器供电情况下的时空谐波分布和存在的谐波转矩,在此基础上建立了六相感应电机的仿真模型,对六相感应电机的特性进行了仿真研究。研究了多相电机的SVPWM技术,针对传统SVPWM方法在多相电机控制方面的不足,提出了一种基于零序平衡矢量的SVPWM控制方法。该方法将多相SVPWM控制算法从多维空间简化到两维空间,在控制零序电压矢量为零的基础上对d-q子空间的电压矢量进行合成,能同时满足d-q子空间和零序子空间的伏-秒平衡,解决了传统SVPWM方法中零序子空间谐波电流不可控的问题,有效地抑制了定子谐波电流。分析了多相电机各空间电压矢量对磁链和转矩的影响,给出了多相感应电机直接转矩控制系统的电压矢量选择方案,阐述了基于零序平衡矢量的直接转矩控制方法。在此基础上,提出了基于转矩预测的模糊直接转矩控制策略,该策略在计算过程中几乎不使用电动机参数,因此具有很强的鲁棒性,既有效地抑制了磁链和转矩的脉动,又很好地保留了传统直接转矩控制的优点。根据多相感应电机的特点,提出了一种多相电机定子电阻的辨识方法,该方法通过观测多相电机零序子空间的谐波电流,采用递推的最小二乘辨识算法来实现定子电阻和漏感的在线辨识。对多相电机缺相运行进行了系统的分析和研究,建立了多相电机在缺相运行时的动态数学模型,详细分析了缺相后电机的性能变化及带负载能力,通过对缺相运行时转矩脉动的分析,出了一种基于转矩脉动抑制的补偿控制策略,该策略不仅消除了缺相运行时转矩的脉动,而且通过绕组等效变换,将不对称系统等效变换为对称系统,实现了缺相运行时磁场定向解耦控制。以六相感应电机为对象,对所提出的SVPWM控制、直接转矩控制和缺相运行控制策略进行了仿真和实验研究,研究结果验证了本文理论分析的正确性和控制方法的有效性。更多还原

【Abstract】 Compared with three-phase motor drive system, multi-phase motor drive system has the advantages such as high power, high reliability and low dc power supply, however, as a new technology, the control of multi-phase machine has still some problems which are worth to be researched and probed in theory and practices. This paper has researched deeply on the theory of the multi-phase induction machine in detail and the control technology of SVPWM, direct torque control and operation in phase-fault conditions.The paper analyzed the winding structure of multi-phase machine firstly, using space vector decoupling, the multi-phase induction machine was decoupled from m dimension to some vertical harmonic sub-spaces, and the mathematic model under harmonic-base for the multi-phase induction machine was built. Then, the time and space harmonics and harmonic torque of the machine supplied by six-phase inverter were analyzed. The simulation studies of modeling six-phase induction machine and its characteristics were performed.The technology of space vector PWM for multi-phase machine was researched. Aimed to the shortage of the conventional SVPWM, a new SVPWM control method was presented based on zero-sequence balancing vector. This method simplified the algorithm of multi-phase SVPWM from multi dimensions to two dimensions, synthesized the vector in the d-q subspace based on zero-sequence voltage vector equaling to zero, it could satisfy the voltage-second balance at the d-q subspace and zero-sequence subspace at the same time, solved the uncontrolled current harmonic in zero-sequence subspace, the stator harmonic current was effectively restrained.According to the characteristics of multi-phase machine, an identification method was presented for the stator resistance of multi-phase machine which through observing harmonic current in zero-sequence subspace and by the recursive least squares estimator identification algorithm, the on-line identification of stator resistor and the leakage inductor was implemented.The effect on flux-linkage and torque of the voltage vector for the multi-phase induction machine was analyzed, a scheme of voltage vector selection for direct torque control of the multi-phase induction machine was given; a new direct torque control algorithm was described based on zero-sequence balancing vector; under this basement, a fuzzy direct torque control strategy was presented based on torque predicting. This strategy hardly used the parameters of machine in calculating and is well robust, it not only restrained the fluctuation of flux-linkage and torque, but also kept the advantage of conventional direct torque control.This paper analyzed and researched the operation of multi-phase machine with phase fault conditions systemically. The dynamic model with phase fault for the multi-phase machine was established. The performances variation and capability of loading under phase fault was analyzed in detail. By analyzing of torque pulsation under phase fault, a compensating control strategy was presented to restrain the torque fluctuation, the strategy not only removed the torque ripple at phase fault, but through the winding equivalent transforming, the asymmetric system was transformed into symmetric ones, the flux linkage orient decoupling control was achieved with phase fault condition.Taking the six-phase machine as object, the simulation and experiments researches were completed for the presented control strategy of SVPWM, direct torque control, and running with phase fault. The results verified the theoretical analyses and the validity of the control strategies.更多还原