A method for controlling a brushless DC motor

Abstract

The invention discloses a control method of a brushless DC motor. The control method of the brushless DC motor can complete the start-up process of the brushless DC motor without a Hall sensor through two stages of frequency conversion forced dragging and fixed frequency operation in sequence. The brushless DC motor only needs to adjust the commutation frequency in its single parameter to effectively locate the initial position of the brushless DC motor rotor, so that the starting work of the brushless DC motor can be realized, and most brushless DC motors without Hall sensors can be effectively positioned. The adjustment of multiple parameters in the motor start control method is simplified to only need to adjust the commutation frequency to realize the start work, thereby reducing the complexity of the brushless DC motor start control, and at the same time avoiding problems such as excessive current or out-of-step. The method is simple and feasible, and the position of the rotor is determined by the counter electromotive force, thereby further improving the accuracy of rotor position detection.

Description

technical field [0001] The invention relates to the technical field of motors, and in particular, to a control method of a brushless DC motor. Background technique [0002] The rotor position of the brushless DC motor at rest is random. To start the motor smoothly, the rotor position must be determined first. For the brushless DC motor without Hall sensor, it is difficult to determine the initial position of the rotor because there is no sensor for sensing the rotor position. In the related art, the starting methods of most of the brushless DC motors without Hall sensors are as follows: [0003] 1. Use the inductance saturation effect to estimate the initial position of the rotor, that is, inject a series of pulse voltage vectors into the stator armature windings, find the voltage vector that maximizes the current response amplitude, and gradually subdivide and approach the rotor position, but this method requires detection. The high-precision sensor with current response a...

AI Technical Summary

Problems solved by technology

[0003] 1. Use the inductance saturation effect to estimate the initial position of the rotor, that is, inject a series of pulse voltage vectors into the stator armature winding, find the voltage vector with the largest current response amplitude and gradually subdivide it to approach the rotor position, but this method requires detection High-precision sensors with current response and complex algorithms increase system cost and complexity;

[0004] 2. Apply a rotating voltage vector with gradually increasing amplitude and frequency in the stator armature winding, and locate the rotor position through the secondary positioning algorithm, but this method introduces vector adjustment of amplitude and frequency, which requires an accurate mathematical model As a theoretical support, if the mathematical model is not accurate enough, it will affect the vibration of the speed or torque when the motor starts

Obviously, the above methods require complex algorithm support, and if necessary, they need to go through multiple software simulation verifications, which increases the difficulty of development

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