【作者】 吉雪花；

【导师】 孙维连； 李纪刚；

【作者基本信息】 河北农业大学 ， 农业机械化工程， 2010， 硕士

【摘要】 直流伺服电动机具有优良的调速特性,调速平滑、简单,具有较大的启动转矩和良好的启、制动性能以及能在较大范围内实现精度、速度和位置控制。同时其过载能力大,能承受频繁的冲击负载,所以在要求系统性能高的场合都广泛地使用直流伺服系统。被广泛应用于轧钢、造纸机、金属切削机床等许多高性能可控电力拖动领域。20世纪80年代后,随着科技的进步,交流调速系统、无刷直流电机的迅速发展,有逐渐取代有刷直流电机调速的趋势。但是直流有刷伺服电机具有独特的优良性能,它可以方便的进行无级调速且有着良好的调速性能,所以直到现在尚未被取代。对一些成本敏感的普通工业和民用场合仍广泛应用。本设计针对调速的可靠性和经济性来设计小功率直流伺服电动机调速系统,不仅工作可靠,成本低,并且具有软启动、恒转矩、宽调速、硬特性等功能,实现了小功率直流伺服电机的平滑无级调速以及电机的保护。该系统主电路采用单相桥式半控整流线路,具有电压负反馈和电流正反馈。本调速系统采用晶闸管变流装置供电的直流调速电路,通过改变晶闸管的导通角来调节输出电压,从而实现在不同速度、不同负载下电动机的平稳运行。对于调速指标要求不高的小功率直流调速系统,采用电流正反馈和电压负反馈的单闭环反馈调速方式,不仅可以获得较满意的动、静态性能(提高机械特性硬度、加大调速范围、加速系统的起制动等),还省去了测速发电机,降低了系统的成本并且给系统的安装和维护提供了方便。最后试验结果也很好的证明了本次控制方案的可行性。本论文首先介绍了直流伺服电动机和直流调速系统的发展概况和直流伺服电动机的主要结构及工作原理,并深入介绍了调速系统的工作原理和调速方法及其比较,然后介绍了本课题中要用到的直流伺服电机。其次本文以经济性好、可靠性高的晶闸管整流为调速系统可控整流电源,对小功率直流调速系统的主电路、转速控制电路进行设计,首先分析了调速系统的性能指标,着重分析了直流伺服电机的数学模型和电压负反馈和电流正反馈的单闭环反馈调速方式的动、静态特性。然后介绍了控制系统的工作原理及保护电路的工作原理。同时考虑到生产实践应用前必须先以软件对系统进行仿真,以控制系统的传递函数为基础,使用Matlab的Simulink工具箱对直流调速系统进行了仿真研究,并做出分析和比较。仿真结果证明了直流调速系统的有效性,同时也验证其他控制算法的合理性,并使生产实践中直流调速系统的可应用性得到了证明。其次,在理论分析的基础上对硬件设计进行实验,检验并实现了最初目的,实验结果证明了系统设计的可靠性。在本文最后,对本课题的工作进行了总结,总结通过本次设计与研究工作中所学到的知识,并展望了未来的工作。更多还原

【Abstract】 DC servo motor has excellent speed control characteristics smooth and simple. It has strong starting torque and excellent starting and braking performance. It can control a large range of accuracy, speed and position. At the same time, it has a good overload capacity and can bear frequent impact loads. Therefore, the DC servo system is widely used in those high performance systems. Now, it has been widely used in rolling mills, paper machines, metal cutting machine tools and many other areas of high-performance controlled power drag.After 20th century 80s, with the development of science and technology, AC speed control system and brushless DC motor has been developed rapidly. And they have gradually replaced the brush DC motor speed trend. But thanks to DC brush servo’s unique high performance, it can easily be variable speed and has good speed performance, so until now, it has not been replaced. It is still widely used in general industrial and civil occasions which is cost-sensitive.This article is to design a economic and reliable speed control system of DC servo motor. The system not only has reliable and low cost, but also has soft start, constant torque, wide speed, hard features and other functions, achieve smooth variable speed of DC motor and protection of the motor. The system of main circuit uses single-phase half-controlled rectifier bridge circuit, with voltage negative feedback and current positive feedback. The system uses thyristor power DC servo motor control circuit, that is by changing the thyristor conduction angle to adjust the output voltage, Therefore the motor can run smoothly at different speeds and different load conditions. According to modern control theory, the control circuit uses negative feedback manner with current compensation. So it can get a more satisfactory static and dynamic performance (improve the mechanical properties of hardness, increased speed range, speed up the system from the brake and so on). It also can eliminate the need for speed generator and reduce system cost. And provide a convenient installation and maintenance. Finally, the experimental results prove the feasibility of this control scheme.Firstly, this paper analyzes the development overview of DC servo motor and DC drive system, introduces the main structure and working principle of DC servo motor and this paper describes in-depth analysis of the basic principles of speed control system and the basic speed control method. Then introduced used of this system to the DC servo motor. Secondly this paper, the economy is good, high reliability and speed control system of thyristor rectifier for the rectification power supply, the main circuit and speed control circuit of the low power DC speed control system are designed, in which thyristors are used as controlled rectifier power. First, analysis the performance index of Speed control system. Emphasis analyzes the DC servo motor and positive current feedback and negative voltage feedback speed control mode static and dynamic characteristics. Then introduces the principle of work of the control system and protection circuit. At the same time, it is convenient for installation and maintenance before production practices to be considered, the system must be simulated in simulation software before application. This system is simulated by MATLAB Simulink Toolbox based on the transfer function of the control system, then related analysis and comparison are introduced. The results are analyzed and compared. Simulation results show the effectiveness of DC speed system, verify the rationality of other control algorithms and prove that DC speed control system can be applied in production practice. Lastly, according to previous theoretical groundwork, the hardware design experiment is operated based on the theoretical analysis. The original purpose is tested and realized. The experimental results show reliability of the system.Finally, this paper summarizes the work done, the knowledge gained through conclusion of this research and design and prospects for future work.更多还原