Control system of direct current motor

Abstract

The invention discloses a control system of a direct current motor for an electric actuator, which comprises an electric machine control unit, a driving circuit and a three-phase brushless direct current motor connected sequentially, wherein the driving circuit is provided with three groups of phase changing circuits which are respectively connected with three phase lines (U, V and W) of the direct current motor. According to the position information of a rotor, the current output of the driving circuit is controlled for phase change. Six paths (UH, UL, VH, VL, WH and WL) of pulse-width modulation signals output by the motor control unit 1 are respectively used for controlling the conduction and disconnection of six upper and lower half-bridge switching tubes of the driving circuit. The system overcomes the defect of poor starting characteristics of an alternating current motor and is convenient for the miniaturized design of the electric actuator. By dynamically regulating the duty ratio of the pulse-width modulation signal, the stable speed control function of the motor is realized. By a method of superposing different pulse-width modulation signals at the upper half bridge and the lower half bridge, the direct current motor is controlled to keep operation at stable speed in states of different external loads.

Description

technical field [0001] The invention relates to the technical field of automatic control, in particular to an electric actuator for industrial process control. Background technique [0002] With the continuous development of social science and technology, the intelligent level of industrial process control has been continuously improved. At the same time, as a requirement to improve the efficiency of industrial processing and production, intelligent control has gradually become the main means of guarantee. The realization of intelligent control requires not only an operating platform with integrated control, but also the intelligence of each process control component. As the main process control actuator, the electric actuator is particularly important for its intelligent update. [0003] In the field of traditional electric actuators, AC motor control systems are basically used. For AC motors, there are the following defects and deficiencies, which bring many difficultie...

AI Technical Summary

Problems solved by technology

[0009] The technical problem to be solved by the present invention is to introduce DC motor control technology into the field of electric actuators, and solve various defects such as insufficient starting torque and difficulty in speed control of traditional electric actuators using AC motors

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