摘要随着科技的进步与发展，在许多工业生产领域，大到国防工业，小至人们的日常生活，三相交流异步电动机都起着重大的作用。简洁明了的构造、方便可靠的操作，便宜的价格都使得三相异步电动机颇受人们的青睐。但是，它也同样存在着一些不足之处。当交流电机启动时，电网电压全部被施加到电动机上，因此造成电动机的启动电流非常大，转矩却很小。过大的启动电流流过交流电机会对交流电机造成巨大危害，恶劣的情况下能够直接烧掉交流电机，而且，供电电网上流过过大的电流，大大增加了它的负荷，对于同一电网进行供电的仪器设备的正常工作造成一定扰动。因此为了减小电动机的启动电流，增大启动转矩，优化启动特性，本文设计了一种以AT89C51单片机为控制核心、以晶闸管为电路核心元件的交流电机软启动器。86065

首先，本文简单的对交流电机的一些较为常见的启动方法作了简单介绍，并且简要叙述了软启动器的结构和工作原理；然后，设计了软启动器的主电路和单片机控制电路等硬件电路；最后开发了软启动器软件程序。本文所设计的软启动器电路简洁、功能完善，能够让交流电机顺利地平滑启动，使之能达到改善三相异步电动机启动性能的要求。

毕业论文关键词：异步电动机；晶闸管；软启动；单片机；设计

Abstract With the progress and development of science and technology in many spheres of industry, large defense industry, small to people's daily lives, three-phase AC induction motor plays a significant role。 Concise structure, convenient and reliable operation, low price have made three-phase asynchronous motors popular people of all ages。 However, it also has some drawbacks。 When the AC motor starting, all the grid voltage is applied to the motor, resulting in motor starting current is very large, very small torque。 Too large starting current flows through the AC motor AC opportunity to cause great harm, a bad situation can be burned directly to the AC motor, and that the power supply grid excessive current flow through, greatly increasing its load, for the same power grid supply working equipment will cause some disturbance。 Therefore, in order to reduce motor starting current, starting torque increases, optimizing start-up characteristics, we design a kind of AT89C51 microcontroller to control the core, the core element of circuit thyristor AC motor soft starters。

Firstly, some of the more common simple method for starting AC motor made a brief introduction and a brief description of the structure and working principle of soft starter; then design a soft start main circuit and microprocessor control circuitry and other hardware circuit ; Finally, the development of the soft starter software program。 This article is designed soft-start circuit is simple, functional, allowing AC motor smooth start smoothly, so that it can achieve improved three-phase asynchronous motor starting performance requirements。

Keywords: Asynchronous Motor; Thyristor; Soft Starter;Singlechip;Design

目录

第一章  绪论 3

1。1 选题的目的和意义 3

1。2 国内外研究现状及存在的问题 3

1。3 主要研究内容 3

第二章  交流电机软启动的研究 3

2。1 交流电机的启动方法 3

2。2 软启动器的结构及其工作原理 3

第三章  交流电机软启动器主电路设计

3。1 主电路的设计