基于多重化与开关变压器的高压电动机软起动技术的研究

发布时间：2018-02-27 05:34

本文关键词： 高压电动机开关变压器软起动串联三重化谐波畸变率 MATLAB仿真　出处：《湖北工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着国民经济的不断发展,各行各业生产规模的不断扩大,作为工业主要动力源的大型电动机的使用越来越普遍。在高压大容量电动机的起动过程中,为了避免由于单个晶闸管的耐压值不够而采用晶闸管串联技术所导致的均压问题,采用开关变压器软起动结构来解决高压电动机的软起动问题,同时针对高压大容量电动机软起动定子电流谐波含量大的问题,将多重化技术引入到软起动技术中,达到降低定子电流的谐波含量,使电动机的起动电流更加接近于正弦波,减少对电网造成的谐波污染,延长电动机的使用寿命。首先,采用短路桥结构代替传统的晶闸管反并联结构,分析结构变化的优势。一方面采用整流桥结构的软起动器在“一拖多”时具有简化电路结构、节省开关与走线的优点,而且使软起动器更方便地与电网进行隔离。另一方面,整流桥结构可以通过多输出端的移相变压器,将多个整流桥正负输出顺极性连接,使其更容易实现多重化软起动,而且整流桥串联可以提高装置的工作电压与功率等级。其次,通过对高压电动机直接起动、传统晶闸管反并联软起动、开关变压器软起动和对这两种结构进行改进的整流桥软起动以及在两种改进后的软起动结构基础上分别引入串联三重化技术的软起动的仿真,仿真结果表明短路桥结构较晶闸管反并联结构具有相同的起动特性,同时综合比较各种起动方式电动机的最大起动电流、起动时间、电磁转矩、定子电流的谐波畸变率等起动指标,发现开关变压器串联三重化软起动在满足限定起动电流的同时,可以大幅度的减少电动机定子电流的谐波畸变率,降低对电网、电动机造成的危害,转矩冲击也大为减少。最后,介绍了软起动控制系统的硬件设计和软件设计。其中硬件设计主要包括主电路,电压同步检测电路,隔离驱动电路,阻容缓冲电路。软件设计主要包括主程序流程图、斜坡电压软起动子程序流程图、电压同步检测流程图。
[Abstract]:With the development of national economy and the continuous expansion of production scale in various industries, the use of large electric motors, which are the main power sources of industry, is becoming more and more common. In order to avoid the problem of voltage equalization caused by the use of thyristor series technology due to the low voltage value of a single thyristor, the soft starting structure of switch transformer is used to solve the soft starting problem of high voltage motor. At the same time, in order to reduce the harmonic content of stator current and make the starting current of high voltage large capacity motor closer to sine wave, the multi-heavy technology is introduced into the soft starting technology to reduce the harmonic content of stator current. To reduce the harmonic pollution to the power network and prolong the service life of the motor, first of all, the short bridge structure is used instead of the traditional thyristor reverse parallel structure. The advantages of structural change are analyzed. On the one hand, the soft starter with rectifier bridge structure has the advantages of simplifying the circuit structure, saving the switch and wiring, and making the soft starter more conveniently isolated from the power grid. The rectifier bridge structure can connect the positive and negative output polarity of multiple rectifier bridges through phase-shifting transformers at multiple output terminals, which makes it easier to realize multi-heavy soft starting, and the series of rectifier bridges can improve the working voltage and power level of the device. By starting the high voltage motor directly, the traditional thyristor is started in reverse parallel. The soft start of switch transformer and the rectifier bridge which is improved by these two kinds of structure and the simulation of soft start of series triple technology are introduced respectively on the basis of the two improved soft starting structures. The simulation results show that the short bridge structure has the same starting characteristics as the thyristor reverse parallel structure. At the same time, the maximum starting current, starting time and electromagnetic torque of various starting modes are compared synthetically. Starting index of stator current such as harmonic distortion rate, it is found that series triple soft start of switch transformer can greatly reduce the harmonic distortion rate of motor stator current and reduce the power grid, while satisfying the limited starting current. Finally, the hardware design and software design of soft start control system are introduced. The hardware design mainly includes main circuit, voltage synchronous detection circuit, isolation drive circuit. The software design mainly includes the main program flow chart, the ramp voltage soft start subroutine flow chart, the voltage synchronization detection flow chart.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM32

【相似文献】