PWM控制直流调速系统毕业设计..doc

PWM控制直流调速系统设计 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十分重要的作用。直流电机是最常见的一种电机，在各领域中得到广泛应用。研究直流电机的控制和测量方法，对提高控制精度和响应速度、节约能源等都具有重要意义。电机调速问题一直是自动化领域比较重要的问题之一。不同领域对于电机的调速性能有着不同的要求，因此，不同的调速方法有着不同的应用场合。 本文基于PWM的双闭环直流调速系统进行了研究，并设计出应用于直流电动机的双闭环直流调速系统。首先描述了变频器的发展历程，提出了PWM调速方法的优势，指出了未来PWM调速方法的发展前景，点出了研究PWM调速方法的意义。应用于直流电机的调速方式很多，其中以PWM变频调速方式应用最为广泛，而PWM变频器中，H型PWM变频器性能尤为突出，作为本次设计的基础理论，本文将对PWM的理论进行详细论述。在此基础上，本文将做出SG3525单片机控制的H型PWM变频调速系统的整体设计，然后对各个部分分别进行论证，力图在每个组成单元上都达到最好的系统性能。 关键词：直流调速 ；双闭环 ；PWM ；SG3525 ；直流电机  DC-drive speed system with PWM ABSTRACT In electrical times today, the electric motor in the industry and agriculture production, the people daily life is playing the very vital role. The direct current machine is the most common one kind of electrical machinery, obtains the widespread application in various domains. The research direct current machines control and the measuring technique, to increase the control precision and the speed of response, the frugal energy and so on have the important meaning. A problem about speed-modulation of DC motor is very important in the field automatic. The requests to the effect after the speed-modulation of the DC motor are different in different fields. Then, different speed-modulation ways are using in different fields. This paper researches DC-drive speed system with a dual-converter and dual-closed-loop based PWM, discussing a new control method that combines PWM with D C-drive, designs applies in direct current motors double closed loop current velocity modulation system. DC motor is used very generally because its speed-modulation effect is very good and its speed-modulation is easily to be realized. PWM theory is used most generally among the speed-modulation ways. The text will introduce the H-PWM way mostly. We will try to do modulation to the DC motor with SG3525. The importance of the text is the parts which are composed the system. Another importance is the principles of working about every parts.  Key word: DC spee