基于最优控制的永磁同步电动机伺服系统研究

发布时间：2018-11-07 18:49

【摘要】：永磁同步电机(PMSM)具有效率高、结构简单等特点,目前以永磁同步电机为控制对象的交流伺服系统已广泛地运用于航天航空、军事国防、工业生产和国民生活等领域。当永磁同步电机被运用于高精度、强抗扰的场合时,由于其是一个强耦合、多变量的非线性系统,传统的PID控制难以实现日益提高的性能需求,因此本文从先进的现代控制理论入手,结合电机本体进行研究,寻求提高永磁同步电机伺服系统驱动性能的方法。本文主要内容如下：本文首先对永磁同步电动机结构进行介绍与分析,并推导了其在常用坐标系下的数学模型。对比了几种常用矢量控制方法,并选定了最合适的id＝0矢量控制,同时对其传统实现方式进行了介绍。提出了一种应用于小电感永磁同步电机,由时间最优控制(TOC)与PI控制组成的混合式电流控制策略,用于改善矢量控制永磁同步电动机的dq轴定子电流动态性能。基于时间TOC理论,推导出控制dq轴电流的最优开关曲线,基于该曲线及电流误差获取dq轴电压,从而使得dq轴电流以最短时间到达给定值。由于实际系统不是连续模型并且电机电感值较小,实验不能达到仿真所实现的效果,因此对TOC控制器进行改进,将其与PI控制进行结合,采用模糊控制器进行切换,取其各自优点,最终实现dq轴电流良好的动态和稳态性能。提出了一种由线性二次型(LQ)最优控制与滑模变结构控制(SMC)相结合的位置控制新策略。在理想条件下PMSM可通过坐标变换,将其数学模型描述成一个线性模型,利用LQ最优控制理论设计位置控制器,以期获得预定的性能指标。但是实际PMSM系统会产生各种不确定因素的影响,当出现外部干扰、参数变化等问题时,单纯的LQ控制性能偏离预定目标,因此结合SMC能够处理不确定非线性系统的特点,可以有效地改善LQ控制鲁棒性差的问题。为了验证本文中所提出的控制策略,以TMS320F2808 DSP为核心,结合矢量控制的特点,进行设计了一套高性能、稳定性好的PMSM伺服系统硬件与软件,并对其中关键部分的实现方法进行了阐述。最后的实验结果表明该硬件系统能够满足所提控制方案的需要,具有可靠性高、实时性好的优点。
[Abstract]:PMSM (permanent Magnet synchronous Motor) (PMSM) has many advantages such as high efficiency, simple structure and so on. At present, the AC servo system with PMSM as the control object has been widely used in aerospace, military defense, industrial production and national life. When PMSM is applied to high precision and strong immunity, because of its strong coupling and multivariable nonlinear system, traditional PID control is difficult to meet the increasing performance requirements. So this paper starts with the advanced modern control theory and studies the motor body to find a way to improve the drive performance of PMSM servo system. The main contents of this paper are as follows: firstly, the structure of permanent magnet synchronous motor (PMSM) is introduced and analyzed, and the mathematical model of PMSM in common coordinate system is derived. Several common vector control methods are compared and the most suitable id=0 vector control is selected. This paper presents a hybrid current control strategy for small inductance permanent magnet synchronous motor (PMSM), which consists of time optimal control (TOC) and PI control. The hybrid current control strategy is used to improve the dynamic performance of the dq shaft stator current of the vector control permanent magnet synchronous motor (PMSM). Based on the time TOC theory, the optimal switching curve for controlling the dq axis current is derived. Based on the curve and current error, the dq axis voltage is obtained, so that the dq axis current reaches the given value in the shortest time. Because the actual system is not a continuous model and the inductance of the motor is small, the experiment can not achieve the effect of simulation, so the TOC controller is improved and combined with the PI control, and the fuzzy controller is used to switch. The good dynamic and steady performance of dq axis current is realized by taking their respective advantages. A new position control strategy combining linear quadratic (LQ) optimal control with sliding mode variable structure control (SMC) is proposed. Under ideal conditions, PMSM can be described as a linear model by coordinate transformation, and the position controller can be designed by using the LQ optimal control theory in order to obtain the predetermined performance index. However, the actual PMSM system will have a variety of uncertain factors. When there are external disturbances, parameter changes and other problems, the performance of simple LQ control deviates from the predetermined target, so combining with SMC can deal with the characteristics of uncertain nonlinear systems. It can effectively improve the problem of poor robustness of LQ control. In order to verify the control strategy proposed in this paper, a set of high performance and good stability PMSM servo system hardware and software is designed with TMS320F2808 DSP as the core and the characteristics of vector control. The realization method of the key part is expounded. Finally, the experimental results show that the hardware system can meet the needs of the proposed control scheme, and has the advantages of high reliability and good real-time performance.
【学位授予单位】：福州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM341

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