Hall Fault Tolerant Control Method for Low Torque Ripple of Permanent Magnet Brushless DC Motor

Abstract

The invention discloses a permanent magnetic brushless direct current motor low torque ripple Hall fault tolerance control method which comprises the following steps: via a vector analysis and coordinate transformation method, brushless direct current motor parameters under an abc coordinate system are converted into alpha and beta coordinate system parameters, an electrical equation comprising electric motor parameters under the alpha and beta coordinate system is obtained; an instantaneous torque equation about a current vector i, a back electromotive force vector e and rotor rotating speed [omega]m is obtained; a movement track of a synthesis current vector ip is obtained; a pulse width modulation PWM is generated, an electric motor is controlled to operate according to requirements, a vector tracking observer is used for subjecting discrete rotor information of a Hall position sensor to estimating operation and then continuous position information can be obtained; a Fourier expansion series analysis tool is used for decomposing and decoupling Hall signals in a normal state and a fault state, a lookup table is used for storing decoupled waveforms of harmonic waves, and the vector tracking observer is used for completing estimating and compensating operation via fundamental wave signal feedback and harmonic wave signal feedback.

Description

technical field [0001] The invention relates to the field of permanent magnet motor control for electric vehicles, in particular to a low-torque ripple Hall fault-tolerant control method for a permanent magnet brushless DC motor. Background technique [0002] Permanent magnet brushless DC motors have higher efficiency and power density than DC motors and induction motors of the same size, so they are widely used in the servo field, as well as electric vehicles, household appliances and other fields. The traditional permanent magnet brushless DC motor is driven by a square wave current with an electrical angle of 120°. Due to the limitation of the inductance of the motor phase winding and the power of the DC power supply, the phase current will not change transiently during commutation, forming a non-ideal square wave current. This in turn leads to commutation torque pulsation. In addition, due to the motor manufacturing process, the counter electromotive force is not ideal, ...

AI Technical Summary

Problems solved by technology

[0004] At present, vector control technology is more and more widely used in the control of permanent magnet brushless DC motors. The high-performance vector control technology greatly reduces the torque ripple of the motor. Since vector control requires continuous rotor position information, the rotor position used Sensors (such as: photoelectric encoders, resolvers, etc.) are expensive, their stability is easily affected by the environment, and the cost of the control system is greatly increased in the low-cost field. Therefore, the low-cost vector control method based on the Hall position sensor has become the focus of research

[0005] However, due to the different application occasions of brushless DC motors, the requirements for the stability of the control system are also different. During the operation of the motor, the Hall position sensor may fail due to the erosive environment, severe jitter, and connection problems, causing the motor to stall or Sudden stagnation, in some occasions with high stability requirements, may lead to serious consequences, posing a great threat to human life and property, so Hall fault tolerance is indispensable in systems with high stability requirements

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