Torque pulse suppression method of brushless DC motor in all speed regulation range

Abstract

The invention discloses a torque pulse suppression method of a brushless DC motor in an all speed regulation range. The torque pulse suppression method comprises the steps of dividing two states of low-speed running and high-speed running according to a motor rotational speed obtained by a speed calculation module; and respectively performing torque pulse control according to the following modes with regard to the two states. By the torque pulse suppression method, existing flux linkage and torque dual-loop control based on direct torque control is simplified, the problem of control system complexity due to the torque and flux linkage dual-closed loop is solved, the problem of control algorithm complexity of the system brought by a sliding-mode observer introduced into an existing method for observing a counter potential is solved, and with regard to high-speed running of the motor, the problem of torque pulse caused by different current change rates of a switch-on phase and a switch-off phase is solved.

Description

technical field [0001] The invention belongs to the field of speed regulation of a brushless direct current motor, and relates to a torque ripple suppression method within the full speed operation range of the brushless direct current motor. Background technique [0002] Due to its excellent speed regulation ability and starting performance, DC motors are increasingly used in electric drive and electric transmission systems. However, traditional brushed DC motors use brushes to commutate mechanically, so there are a series of problems such as poor reliability, short life, many faults, maintenance, high noise, and electromagnetic interference caused by commutation sparks. However, its application in some special fields is limited. The brushless DC motor is a new type of DC motor developed on the basis of the brushed DC motor. It has the advantages of simple structure, long life, small size and high efficiency. Due to the use of electronic commutation, the mechanical contact...

AI Technical Summary

Problems solved by technology

[0006] The disadvantage of the above technology is that the patent CN200610037967.2 adopts the double closed-loop control of the torque loop and the flux linkage, and the acquisition of the motor flux linkage needs to be estimated by a certain algorithm

For brushless DC motors, in order to obtain better control performance, the given stator flux amplitude should be a function of position, which makes the system more complicated and greatly increases the control cost

Although the patent CN201010127885.3 adopts the torque single closed-loop control to realize the flux-free control of the brushless DC motor, but due to the torque calculation module T e The estimation of needs to use the sliding mode observer to observe the back electromotive force, which increases the calculation cost of the system; in addition, because this scheme only performs chopping control on the on-phase, and when the motor is running at high speed, the off-phase current drops faster than the on-phase current If the current rise speed is high, it is necessary to delay the shutdown process for the off-phase, otherwise the current change rate of the on-phase and the off-phase will be different, which will cause a large torque ripple and poor performance of the motor. Therefore, the above patent The proposed method is only effective when the motor is running at low speed

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