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无刷直流电机转速控制系统的研究与设计

Research and Designe on Speed Control of Brushless DC Motor

【作者】 朱海舟

【导师】 樊绍胜;

【作者基本信息】 长沙理工大学 , 控制理论与控制工程, 2012, 硕士

【摘要】 无刷直流电机(BLDCM)是近年来迅速发展起来的一种新型直流电机,它通过外部电子电路换相来代替传统的机械电刷换相,克服了传统直流电机因为电刷与换向器之间的摩擦而带来的电火花、电机损耗及噪音等一系列问题,并具有体积小、调速性能好、输出转矩大、效率高等优点,因而受到了广泛关注。随着电力电子技术的迅速发展以及稀土永磁材料的不断涌现,使得它在国民经济生产的各个领域以及人们的日常生活中具有非常广阔的应用范围和市场前景。因此,对其控制系统的研究具有重要的理论指导和实际工程意义。本文以无刷直流电机为主要研究对象,着重研究了其转速系统的控制方法。论文首先阐述了无刷直流电机控制技术的研究背景及意义,介绍了无刷直流电机的发展历史和国内外控制研究现状,比较分析了PID控制,变结构控制,模糊控制及神经网络控制在无刷直流电机控制领域中的应用。其次,根据无刷直流电机的基本结构及其工作原理,通过分析其数学模型,阐述了无刷直流电机的运行特性和调速方法。然后针对无刷直流电机非线性、多变量的系统因素,考虑到传统PID控制难以对其进行高精度控制,结合模糊控制和PID控制的特点,设计了模糊PID控制器,并将控制器应用于无刷直流电机转速外环控制中,通过Matlab软件建立了无刷直流电机双闭环转速控制系统的仿真模型。仿真结果表明,相对传统PID转速环控制,采用模糊PID控制使系统响应速度加快,动、静态特性及鲁棒性能变得更好。由于模糊控制是基于规则控制的,规则的产生和调整往往依赖于专家经验,为进一步提高系统的整体控制性能,本文在模糊PID控制的基础上又进行了改进,融合了神经网络自适应控制,针对转速外环设计了一种基于最优二次型单神经元模糊自适应PID控制器,仿真结果表明采用二次型单神经元模糊PID控制所取得的控制效果均优于传统的PID控制和模糊PID控制。最后以DSP2407为主控芯片进行了无刷直流电机转速控制系统的硬软件设计,并对系统进行了实验,实验结果符合理论分析。硬件电路设计主要包括主电路,功率驱动电路,转子位置检测电路,相电流检测电路;软件部分采用自上而下的模块化设计方法,主要包括主程序模块与中断服务程序模块。其中主程序模块包括系统初始化、电机启动程序以及循环调用中断服务子程序。中断服务程序模块主要包括位置信号捕获中断子程序、A/D转换中断子程序。

【Abstract】 The brushless DC motor(BLDCM) is a new style motor in recent years whoseelectronic commutator is used instead of mechanical one, which overcomes a seriesof disadvantages of the traditional DC motor caused by the brush friction withelectrical sparkle、motor loss and noise. Furthermore, BLDCM has many advantages,such as small volume, good regulating performance, large output torque and highefficiency. With the development of power electronics and new permanent magneticmaterials, it is widely applied to every field of national industry and people’s dailylives with broad market prospects, therefore, study on the control system forBLDCM has important theoretical and practical significance. The paper chooses thespeed control system of BLDCM as the main object of research, its speed controlmethod has been studied.Firstly, the research background and significance of the brushless DC motorcontrol are elaborated. Then the control technology development history and thecurrent study of domestic and international of the BLDCM are introduced andfocusing on analysis of PID control, variable structure control, fuzzy control andneural network control system and so on.Secondly, the operation principle and speed control method is deduced in detailbased on the structure and mathematical model of BLDCM. BLDCM is a nonlinear,multivariable system, the traditional PID control is difficult to meet itshigh-precision control, therefore, a fuzzy PID controller is designed and applied tothe speed outer loop control of the brushless DC motor system combining with thecharacteristics of fuzzy control and PID control, then the simulation model of theBLDCM speed control system in MATLAB is built. Simulation results show that theuse of fuzzy PID control system make response speed fast, whose dynamic and staticcharacteristics and robust performance is better than that of PID control. As theperformance of fuzzy control is based on the fuzzy rules, the generation andadjustment of rules always rely on expert’experience, To further enhance the overallperformance of control system, combining the neural network adaptive control basedon the improvement of fuzzy PID control, a quadratic single neuron fuzzy adaptivePID controller is designed on the speed outer loop. The simulation results show thatthe quadratic neuron fuzzy PID control achieved good control effectiveness, which is both better than the traditional PID control and fuzzy PID control.Finally, the brushless DC motor speed control system based on DSP2407 onhardware and software has been designed. Meanwhile, studying through experimentsof the system is done, and the experimental results coincide with the theoreticalanalysis. The hardware part mainly includes power driving circuit, rotor positiondetection circuit, the phase current detection circuit, the speed given and displayingcircuit. The software part mainly constitute completion of the main program and theinterrupt service program. The main program achieves system initialization, theprocess of motor starting and calling interrupt service routine in a loop. Theinterrupt service program includes the interrupt subroutine of capturing positionsignal and A/D conversion.

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