基于模型预测开关磁阻电机控制系统研究

发布时间：2018-07-15 20:03

【摘要】：开关磁阻电机(SRM)结构简单坚固、工作稳定可靠、成本低廉、控制灵活,近些年来颇受关注。开关磁阻电机驱动系统(SRD)亦发展迅猛,现已广泛应用于矿山开采、石油开采、电动车驱动和家电等诸多工业领域。然而,由于SRM的结构以及控制方式的原因,使得电机的转矩波动较大,这就限制其在高精度控制领域的应用。因此,如何有效的减小SRM转矩脉动逐渐成为了国内外学者的研究热点之一。本文基于模型预测的控制方法,对开关磁阻电机调速系统进行研究,在分析了有限开关控制集的模型预测控制方法的优缺点之后,通过对优化后的电流波形进行无差拍的预测控制,实现减小SRM转矩波动的控制。本文首先分析总结了国内外在减小SRM转矩脉动优化方面的研究进展,介绍了SRM的基本工作原理、数学方程和一般控制方法以及功率电路。之后,为了获得电机准确的磁链模型,给出了一种在线获取模型参数的实验方法,其实质上就是一种SRM磁链特性的在线检测方法。先从控制器自身角度,分析了软件磁链估算在静止或极低速条件下的误差来源,并根据所提出等效电阻校准方法对磁链估算进行了修正。然后给出了两种在线检测的具体运行方案,并通过转速开环的方案获得了18.5k WSRM磁链特性数据。紧接着介绍了一种基于转矩最小化情况下,获得最优的参考电流的方法,为后文的实验仿真部分提供数据支持。随后,在介绍了模型预测控制(MPC)基本原理以及基本特点的基础上,实现了基于有限开关控制集模型的控制系统,实现了对电机转矩脉动,电流大小,以及开关频率的控制,对于该控制系统中电流波动大,以及开关频率不固定,谐波含量高的问题,提出了一种改进的模型预测控制方法,即无差拍的模型预测控制,基于前文获得的转矩波动最小化的最优的电流,实现对参考电流的无差拍预测控制,以此来减小电机转矩的脉动。最后,本文介绍了控制系统的硬件组成和软件结构,并通过实验平台完成了基于模型预测的电机运行测试。实验结果表明:在全速范围内,该控制器可以实现对参考电流实现较好的跟定,实现对转矩脉动的抑制作用,同时,输出转矩能够快速跟随负载与转速的变化,实现了电机的高性能控制,具有一定的实用性与参考价值。
[Abstract]:Switched reluctance motor (SRM) has attracted much attention in recent years due to its simple structure, reliable operation, low cost and flexible control. Switched reluctance motor drive system (SRD) has been widely used in many industrial fields, such as mining, oil mining, electric vehicle driving and home appliances. However, due to the structure and control mode of SRM, the torque fluctuation of the motor is large, which limits its application in the field of high-precision control. Therefore, how to effectively reduce SRM torque ripple has gradually become one of the hot research topics of domestic and foreign scholars. Based on the model predictive control method, the switched reluctance motor speed control system is studied in this paper. After analyzing the advantages and disadvantages of the model predictive control method of the finite switch control set, In order to reduce the torque ripple of SRM, the optimized current waveform is predicted and controlled without beat. This paper firstly analyzes and summarizes the research progress in reducing the torque ripple of SRM at home and abroad, and introduces the basic working principle, mathematical equation, general control method and power circuit of SRM. Then, in order to obtain the accurate flux model of the motor, an experimental method to obtain the parameters of the model on line is presented, which is in fact an on-line detection method for the characteristics of the SRM flux chain. In this paper, the error sources of the software flux estimation under static or very low speed conditions are analyzed from the point of view of the controller itself, and the flux estimation is modified according to the proposed equivalent resistance calibration method. Then two specific operation schemes of on-line detection are given, and 18.5k WSRM flux characteristic data are obtained by the open-loop rotational speed scheme. Then a method based on torque minimization to obtain the optimal reference current is introduced, which provides the data support for the later part of the experiment simulation. Then, on the basis of introducing the basic principle and characteristics of Model Predictive Control (MPC), the control system based on finite switch control set model is realized, and the torque ripple, current magnitude and switching frequency of motor are controlled. For the problems of large current fluctuation, unstable switching frequency and high harmonic content in the control system, an improved model predictive control method, that is, model predictive control without beat, is proposed. Based on the optimal current of torque ripple minimization obtained in the previous paper, the non-beat predictive control of reference current is realized to reduce the torque ripple of motor. Finally, this paper introduces the hardware structure and software structure of the control system, and completes the motor operation test based on model prediction through the experimental platform. The experimental results show that the controller can follow the reference current well and restrain the torque ripple in the full speed range. At the same time, the output torque can follow the change of load and speed quickly. The high performance control of the motor is realized, which has certain practicability and reference value.
【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】：TM352;TP273

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