A control method for a speed-regulating drive system of a series-excited motor

Abstract

The invention discloses a control method for a speed adjustment driving system of a series motor. According to the invention, a direct-current chopping voltage-regulating power source is adopted to supply power to the series motor, and an electronic controller is adopted to adjust the on-off duty ratio of power electronic switching devices in the direct-current chopping voltage-regulating power source and control the terminal voltage of the motor in a manner of pulse width modulation. The control method disclosed by the invention has the advantages that the rotating speed of the series motor can be detected without a speed sensor; rotating speed and current feedback control is introduced, so that on the premise of maintaining the soft mechanical properties of the system, the defects, for instance that the rotating speed increases to a dangerous value when the system is in idle running at high voltage, serious overload happens during locked rotor and the locked rotor phenomenon easily happens during low speed running at low voltage, in the mechanical properties of the speed adjustment driving system of the open-loop series motor are eliminated.

Description

technical field [0001] The invention relates to a control method for a speed-regulating drive system of a series-excited motor, belonging to the technical field of motor control. Background technique [0002] Series-excited motors have soft mechanical properties and are used in electric tractors, electric tools, sewing machines and mixers, etc., which require motor-driven equipment with soft mechanical properties. Open-loop voltage regulation is a commonly used speed control method for series-wound motor speed-adjustable drive systems, but this method has inherent defects in the characteristics of series-wound motors: the speed of series-wound motor speed-adjustable drive systems will increase when they are running at high voltage without load. To a dangerous value, when the rotor is locked, the locked rotor current is too large; when the motor is running at low voltage and low speed, the driving ability of the motor will drop sharply. [0003] In order to solve the above p...

AI Technical Summary

Problems solved by technology

Open-loop voltage regulation is a commonly used speed control method for series-wound motor speed-adjustable drive systems, but this method has inherent defects in the characteristics of series-wound motors: the speed of series-wound motor speed-adjustable drive systems will increase when they are running at high voltage without load. to a dangerous value, when the rotor is locked, the current of the locked rotor is too large; when the motor is running at low voltage and low speed, the driving ability of the motor will drop sharply

[0003] In order to solve the above problems, adopting the commonly used speed and current feedback closed-loop control strategy will cause the series excitation motor drive system to lose its original soft mechanical characteristics, and the speed measurement device with increased speed feedback will significantly increase the manufacturing cost of the system

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