SCM control dc speed control system

1 introduction Dc motor has good up, braking performance, like at the wide range smoothing speed regulation, in rolling mill, mine hoist, excavator, high-rise elevator and so on need high performance controllable electric drive field application has a long history. High power dc speed regulation system usually adopts three-phase full control bridge rectifier circuit of motor for power supply, so as to rotating joint control motor speed, the traditional control system adopts the simulation component, although in a certain extent satisfy the production requirements, but because element easy ageing and in use is easy the interference effect, and circuit complexity, poor universality, the control effect is device performance, the influence of such factors as temperature, therefore, the operation of the system reliability and accuracy is not guarantee, appear even accidents.

At present, the dc motor speed control system digital has to practical, its main features are: simple structure, convenient maintenance, dynamic parameter adjustment convenient, system reliability is high, can use digital filter to enhance the system anti-interference performance, can use digital feedback to rotary union improve the precision of the system, has the information storage and data communication function and low cost. 2 general structure design 2.1 the choice of control scheme This design choose V - M system. Because of the requirements of dc voltage ripple is lesser, it adopts three-phase rectifier circuit. Consider making circuit is simple, economic and meet performance requirements, select the thyristor three-phase full control bridge power supply scheme. And thyristor controlled rectifier device no noise, no wear, fast response, small volume, light weight, saving investment.

And the work reliable, small energy consumption, high efficiency. Heald selected thyristor three-phase full control bridge rectifier circuit power supply scheme [1]. 2.2 general structure design The speed the current double closed loop speed regulation system [2], in the system set up two regulator, respectively adjustment speed and current, a cascade connection between them, so that can be achieved in the starting process only current negative feedback, but it is not the same as the negative feedback speed and add to a regulator input end to steady speed, rely on speed negative feedback, not by current negative feedback to play a major role, so that it can get good static and dynamic performance. To fiber optic rotary joint sum up, this system USES a microcontroller and external expansion equipment instead of the original analog system speed regulator, current regulator, trigger, lock zero unit and current adaptive regulator, etc., so that the dc speed control system to realize full digital. Its hardware structure such as 1 shows. 1 single-chip microcomputer control dc speed control system structure