Direct torque brushless DC servo control system and its working method

Abstract

The present invention relates to a direct-torque brushless DC servo-control system and the working method thereof. The controller includes a coordinate transformation unit, a magnetic linkage computing unit, a torque computing unit, a magnetic linkage and a torque hysteresis control unit, a switch watch and an inverter unit; in the direct-torque brushless DC servo-control system in the present invention, the magnetic linkage and torque hysteresis control unit are used for comparing the stator magnetic linkage Psi s from the magnetic linkage computing unit and the stator torque Te from the torque computing unit respectively with the reference value Psi s * and T*e, and for outputting the magnetic linkage adjusting signal Tau and torque adjusting signal Phi having the corresponding frequency of 4-8kHz according to the compared result to improve the switch frequency of the inverter and reduce the torque pulsation. The system in the present invention has a good control effect to the torque and a quick response, and the problem of the torque pulsation of the brushless DC electric motor is solved.

Description

technical field [0001] The invention relates to the field of automatic control, in particular to a direct torque brushless DC servo control system and its working method. Background technique [0002] In the past, the screen door system was mostly composed of a single-chip microcomputer driving a DC brushed motor through a reducer. This control method has a large loss, low control accuracy and short life. Brushless DC motor is a component without commutator, which can effectively overcome the problems of torque fluctuation and electromagnetic interference caused by commutation sparks of brushed DC motor, and is easy to control, especially when combined with PWM drive technology Finally, the brushless DC motor can achieve higher precision in control. The use of brushless DC motors to realize the direct drive of the screen door machine not only simplifies the mechanical structure of the screen door device, but also reduces the manufacturing cost, and is convenient for instal...

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Problems solved by technology

[0009] The disadvantages of the above-mentioned prior art are: according to the principle of direct torque control, Fig. 6 (a) is a torque hysteresis comparison control waveform diagram in the prior art, T * e It is the ideal value of the hysteresis comparison of the torque input by the system, and the torque hysteresis comparison threshold, ΔTe, is used to adjust the torque

When the input frequency of the system is high and changes frequently, t1 and t2 are uncontrollable and uneven, that is, the switching frequency is not fixed, which is not good for filtering

This is also the direct cause that affects the torque control effect of the prior art

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