【作者】 曲兵妮；

【导师】 宋建成；

【作者基本信息】 太原理工大学 ， 电机与电器， 2010， 博士

【摘要】 本文的研究内容是国家科技支撑计划项目“矿井通风及供电系统安全状态监测及故障诊断预警系统的研究”(2007BAK29B05)中的一个子项目。开关磁阻电机(Switched Reluctance Motor, SRM)具有结构简单、控制灵活、起动性能好、可缺相运行等优点,得到了学术界和工业界的广泛关注,其应用已涉及工业、航空、家用电器等领域。由于SRM的双凸极结构和电磁特性的高度非线性,使其转矩脉动较其它传统电机严重。当工作在两相励磁模式时,相间磁场相互耦合,非线性数学模型更加复杂,难以实现高性能的控制,限制了其在诸如伺服驱动等低速要求平稳场合下的应用。因此,研究SRM两相励磁工作模式下的互感,以及计及相间互感的准确数学模型和转矩脉动抑制控制技术具有重要的理论价值和现实意义。本文分析了SRM单相和两相励磁模式下磁场的分布特征,研究了偶数相SRM磁场的不对称性;用有限元法计算了单相和两相励磁模式下的两相总磁链特性,以互感的形式表征两种励磁方式下磁链的差别;提出了互感的计算模型,计算了互感随转子位置和绕组电流的变化规律;建立了两相励磁模式下计及互感的磁共能计算方法,理论分析了互感对静态矩角特性的影响;结合功率电路,对SRM进行了时步有限元分析。研究结果表明:绕组电流较大时互感为负,两相励磁模式下的总转矩小于两相分别单相励磁时的转矩之和,瞬时转矩波形不规则。研究了SRM具有不同几何设计参数时互感的变化规律,提出适当增加定子轭高/齿宽比或减小转子极弧长可以减小互感;针对互感导致转矩波形不规则问题,探讨了几种降低互感对转矩影响的补偿性方法,提出适当增加长磁路励磁相绕组匝数和斩波电流的方法,可以改善转矩波形的不规则性,并给出了绕组匝数和斩波电流的计算模型。实验测量了开关磁阻电机样机在单相励磁模式下的静态电磁特性;结合电机的实际运行情况,提出了SRM相邻两相绕组同时励磁条件下互感的测量方法;测量了电机磁场相对饱和条件下,互感随转子位置和相电流的变化规律,将测量结果与有限元计算结果相对比,二者基本吻合。推导了计及相间互感的电动势平衡方程和转矩平衡方程;采用最小二乘支持向量机方法训练SRM电磁模型,结果表明:该方法训练速度快,模型精度高。将长磁路励磁相的互感特性纳入数学模型中,构建了基于最小二乘支持向量机的SRM调速系统仿真模型,并进行了仿真和实验验证;实验结果证明了计及互感的最小二乘支持向量机建模方法的正确性和有效性。提出了基于转矩补偿的转矩脉动抑制控制策略,该方法能够对电磁不对称励磁相的互感转矩进行补偿;推导了补偿相开通角和关断角的选择方法与计算模型,以及额定负载条件下最大转速估算模型;结合转矩逆模型,建立了能够补偿互感转矩的SRM低转矩脉动调速系统仿真模型,并进行了仿真。结果表明:转矩脉动明显减小;与不对互感转矩补偿的转矩脉动抑制方法相比,对互感转矩补偿后的转矩脉动程度小。研发了基于TMS320LF2407 DSP的开关磁阻电机调速系统控制器,设计了冗余电容裂相式功率变换器。在调速系统实验平台上完成了高速和低速稳态运行实验、动态运行性能测试实验、起动运行实验以及容许输出测定实验。实验结果表明,系统静态误差小,鲁棒性较强,抗干扰能力好。更多还原

【Abstract】 The research topic in this thesis is one of the important parts of the project“Study on the safety state monitoring system and fault diagnosis and early warning system of underground power distribution and ventilation networks in coal mine”(2007BAK29B05), which is supported by National Science & Technology Pillar Program of China. The Switched Reluctance Motor (SRM) continues to attract a lot of research interests in academe and industry due to its simple structure, flexible control, excellent starting performance and phase-deficient operation characteristics. The SRM has been widely applied in the fields of industry, aviation,household electric appliance, etc. However, owing to its doubly salient pole structure and highly nonlinear electromagnetism characteristics, the torque ripple of SRM is much serous than that of the conventional motors. When the SRM operates under the condition of two-phase excitation mode, the magnetic field coupling between the phases will occur. The mathematic model becomes much complicated and the high performance control is difficult to be achieved. In other words, the SRMs couldn’t be applied in the servo driving system which request stationary torque at lower speed. As a result, it is of important theoretical value and practical significance to conduct the research on the mutual inductance under the condition of two-phase excitation, the accurate mathematic modeling considering mutual inductance and control strategy to minimize the torque ripple.In this thesis, the distribution features of magnetic field in single-phase excitation mode and in two-phase excitation mode are presented respectively, and the magnetic asymmetry in even phase SRM is analyzed. The total flux-linkage characteristics under the condition of single phase excitation mode and two-phase excitation mode are calculated by Finite Element Analysis (FEA) separately, and the difference between them is demonstrated by mutual inductance. The mutual inductance calculation model is put forward. The variety of mutual inductance with rotor position and phase current is calculated. The calculation method of co-energy is established considering the mutual inductance in two-phase excitation mode, and the mutual coupling effect on static torque-angle characteristic is theoretically analyzed. The time-stepping FEA analysis is carried out combining with the actual power converter. It has been shown by the research result that the mutual inductance is negative with larger current; the total torque in two-phase excitation mode is less than the sum of torques of the two phases in single-phase excitation mode; the instantaneous torque waveform is irregular.The variety of mutual inductance with different geometric parameters is discussed and it has been found that the mutual inductance can be reduced by increasing the proportion of the width of stator yoke and tooth appropriately or by decreasing the length of rotor pole arc. In view of the irregularity of torque waveform induced by mutual coupling, several compensatory measures are investigated to reduce the mutual coupling effect on torque. It is proposed that increasing the winding turns or chopped current properly could improve the regularity of torque waveform. The formula for calculating the winding turns and chopped current are also presented in this thesis.The static characteristics of the SRM prototype in single-phase excitation mode are measured by experiments. The method to measure the mutual inductance between two adjacent phases excited simultaneously is proposed, which is based on the practical running situation of SRM. The variation of mutual inductance with respect to rotor position and phase current has been measured and it has been found that the measured results are consistent with that calculated by FEA.The potential balance equation and torque balance equation considering mutual inductance are derived. The electromagnetic models of SRM are trained by Least Squares Support Vector Machine (LS-SVM). It has been shown by training results that this method is of rapid training speed and the trained models are highly accurate. The simulation model of Switched Reluctance Drive (SRD) system, which considers mutual inductance, is established based on LS-SVM. The SRD system is simulated and experimented. It has been verified by experimental results that the modeling method by LS-SVM considering mutual inductance is correct and effective.A torque ripple minimization control strategy based on torque compensation is proposed, which can compensate the torque caused by mutual inductance of asymmetric phases. The selection and calculation method of turn-on and turn-off angles, as well as the estimation method of the maximum speed at rated load are set up. In consideration with the torque inverse model, the simulation model of low torque ripple switched reluctance motor drive system, which can compensate the mutual inductance torque, is established and simulated. Simulation results show that the torque ripple is effectively reduced, and the degree of torque ripple with mutual torque compensation is lower than the one without mutual torque compensation.The controller of switched reluctance drive system based on TMS320LF2407 is developed and a redundant split-phase power converter is designed. A series of experiments, such as steady-state running at high and at low speed, dynamic running, starting operation, allowed output torque and so on, have been carried out. It has been shown by the experiments that the developed SRD system is of low static error, strong robustness and strong anti-interference ability.更多还原