A Method of Instantaneous Torque Control of Brushless DC Motor Based on Current Control

Abstract

The invention discloses an instantaneous torque control method of a brushless direct-current motor based on direct-current control. The control method comprises the following steps: a two-phase current value of the motor is detected by using a current sensor and a current value of another phase is calculated; a rotor position of the motor is detected by using a position sensor; the instantaneous torque required at present is obtained through calculation and comparison; an optimal reference current is obtained through a torque coefficient reciprocal database in combination with the rotor position; the optimal reference current is compared with a current obtained through the selection so as to obtain a duty ratio D1; the duty ratio D1 is added to a duty ratio D2 corresponding to a counter potential of which the rotate speed is in direct ratio so as to obtain a final duty ratio D; the final duty ratio D, a rotate speed instruction, the negative and positive of the optimal reference current and rotor position information are input into a switch state checking table together; a corresponding switch mode is selected to drive the brushless direct-current motor to operate, thus the four-quadrant operation of the brushless direct-current motor is realized, the control to the rotate speed of the motor and the instantaneous torque is realized, and the purpose of suppressing an electromagnetic torque pulsation of the brushless direct-current motor is achieved.

Description

technical field [0001] The invention relates to the technical field of control of brushless direct current motors, in particular to a method for controlling instantaneous torque of brushless direct current motors based on current control. Background technique [0002] The permanent magnet brushless DC motor is a special motor that uses electronic commutation for the disadvantages of mechanical commutation of traditional DC motors. It has the advantages of simple structure, high power density, small moment of inertia and high efficiency. It uses electronic commutation to replace mechanical Commutation, it maintains the good performance of the DC motor, has good starting and speed regulation characteristics, because it does not require mechanical commutation equipment, so there is no need to replace the brush due to wear and tear, in aerospace systems, national defense military equipment, industrial Automation, transportation and other fields have been widely used. During the...

AI Technical Summary

Problems solved by technology

However, this method has obvious low-frequency torque ripple, which limits the application of brushless DC motors in high-performance servo systems

Furthermore, there is also a current PWM control technology with current shaping to better suppress torque ripple, but the required appropriate reference current is relatively complicated and not easy to achieve

In addition, there is a method of accurately detecting the commutation time of the three-phase AC and performing current compensation during the commutation period in order to reduce the torque ripple, but the control algorithm is more complicated to implement, so it is difficult to popularize in practical applications

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