摘要电机分为直流电机和交流电机。直流电机由于需要滑环和巨大的整流子，因此功率一般不会很大，当直流电机作为拖动设备时，因其受到自身因素的限制很难得到广泛的应用。因此，大多使用三相异步电机作电动机使用，最常见的异步电机就是三相异步电机。一般将其作电动机使用，在工厂、煤矿等使用较多，日常生活也会用到。如：应用于井下的提升机、高楼大厦里的电梯、农村应用较多的水泵等等。虽然异步电动机有很多优点，应用也很广泛，但是三相异步电动机也存在明显的缺点，它的起动转矩较小，而起动电流却很大，这对电机本身以及电网安全可靠运行都非常不利，因此限制了三相异步电动机的应用。为了减小起动电流，削弱对电网的冲击，传统的降压起动设备虽然改善了异步电动机的起动特性，但也存在着诸多问题。因此，我打算通过使用单片机控制晶闸管来控制电动机的软起动。该起动方式可以减缓电机的加速，避免大电流对电网的冲击，提高电能质量。74072

这篇论文的设计思路是这样的：重点介绍其硬件电路，按照一定的调理分块描述其工作原理。软件部分主要是体现设计思路即可，关键还是其硬件电路。

该论文有图25幅，参考文献20篇。

毕业论文关键词： 软起动  三相异步电动机  晶闸管  单片机

Research on Soft Starting Control System of Three Phase Asynchronous Motor

Abstract

Motor is pided into DC motor and AC motor。 DC motor due to the need for slip ring and a great deal of commutator, so power is generally not greatly, when DC motor as the driving equipment, because of its by its own factors limit is difficult to be widely used。 But the AC motor has the big flaw in the start, generally only uses for the generator to use。 The most widely used should belong to asynchronous motor。 It is used as an electric motor to be used in industrial and mining enterprises, of course, in our daily life also has application。 Such as: applied to the underground elevator。 Although asynchronous motor has many advantages, the application is also very extensive, but three-phase asynchronous motor also has obvious shortcomings, the starting torque is small, and the starting current is large, the motor and the power grid safe and reliable operation is very bad, thus limiting the application of three-phase asynchronous motor。 In order to reduce the starting current and weaken the impact on the power grid, the traditional buck starting equipment improves the starting characteristics of the asynchronous motor, but there are many problems。 Therefore, I intend to use the microcontroller to control the thyristor to control the soft starter motor。 The starting method can reduce the acceleration of the motor, avoid the impact of large current to the power grid, and improve the quality of power。

The design idea of this paper is: the focus of the hardware circuit, according to a certain conditioning block description of its working principle。 Software is mainly reflected in the design ideas can be, the key is the hardware circuit。

Keys word: Soft star  Three-Phase  Synchronous Motors  Thyristor Microcontroller

目录

摘要 I

Abstract II

目录 III

1 绪论 1

1。1 题研究的背景、目的和意义 1

1。2 起动技术的现状和发展前景 1

2 三相异步电动机的起动原理及方式 3

2。1 三相异步电动机的起动原理