双闭环毕业设计.doc

摘 要 在电气时代的今天，电动机在工农业生产、人们日常生活中起着非常重要的作用。直流电机是比较常见的一种电机，在各领域中得到了非常广泛应用。直流电机调速问题一直是自动化领域非常重要的问题之一。采用传统的调速系统主要有以下缺陷：模拟电路非常容易随时间漂移，会产生一些不必要的热损耗，并且对噪声十分敏感等。本文从直流调速系统原理出发逐步建立了双闭环直流PWM调速系统的数学模型，Matlab软件建立了调速系统的仿真模型。在建立系统计算机仿真模型时，由于系统复杂，首先利用MATLAB的子系统模块将主电路和触发电路封装成一个子系统；然后将子系统与其他模块一起组成整个调速系统的仿真模型。利用仿真软件中仿真功能对系统进行了仿真，仿真的结果证明了该方法的可行性、合理性。利用仿真技术可以很大程度地减少双闭环可逆直流调速系统设计和调试强度。 利用直流电动机的双闭环调速，此系统使直流电机具有优良的调速特性，调速方便，调速范围广，过载能力大，能承受频繁的冲击负载，制动和反转，能满足生产过程自动化系统的各种特殊运行要求。 Abstract In the age of electricity, electric motor plays a very important role in the industrial and agricultural production and peoples daily life. DC motor is a much more common form of motor and has been very widely used in various areas. DC motor’s speed mutilation is one very important issue in the automation. The traditional control system has the following shortcomings: analog circuit is very easy to drift over time and sensitive to noise, producing some unnecessary heat loss and so on. It gradually establish a mathematical model of double-loop DC PWM speed control system based on the principle of the DC speed control system. In the complex system designed，there are many parameters that need to be calculated and adjusted. For the traditional methods，the design work is hard. With development of computer technology，it provides a platform with hardware and software. The system simulation model is built with the Matlab software. When the system model is made，a subsystem is packed with main circuit and trigger circuit. The result of the simulation is practical and reasonable. The design work can be much reduced when using the simulation technology. Using DC H bridge speed regulation system based on double closed-loop control, this system enables DC motor has excellent speed features, easy to speed, wide speed range and large overload range. Besides， this system can withstand frequent impact loads, brake and reversion. Above all, this system can meet various special running requirements in the production process auto