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A Phase Detection Method of BLDC Motor Based on Back EMF Peak and Valley

A phase detection and back EMF technology, which is applied in the direction of electronically commutated motor control, electrical components, control systems, etc., can solve the problems of large changes in detection results, large influence of reference phase, reference phase fluctuations, etc., to avoid excessive detection errors Large, strong anti-disturbance effect

Active Publication Date: 2018-07-27
INST OF MACHINERY MFG TECH CHINA ACAD OF ENG PHYSICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method is greatly affected by the reference phase, the reference phase fluctuates, and the detection results vary greatly

Method used

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  • A Phase Detection Method of BLDC Motor Based on Back EMF Peak and Valley

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] 1a. The back EMF detection is carried out through the driving line of the BLDC motor, and the periodic signal of the electric potential changing with time is obtained;

[0018] 1b. The periodic signal that the potential changes with time is transmitted to the filter circuit module, and the analog signal is obtained after being filtered by the filter circuit module, and the analog signal is converted into a digital pulse signal I through a differential trigger circuit; figure 1 As shown, digital pulse signal I generates digital pulses at π of phase a, 2π / 3 of phase b, and π / 3 of phase c.

[0019] 1c. The digital pulse is used for phase angle compensation in the CPU of the DSPIC microcontroller to obtain the commutation angle of the BLDC motor.

Embodiment 2

[0021] 2a. The back EMF is detected through the driving line of the BLDC motor, and the periodic signal of the electric potential changing with time is obtained;

[0022] 2b. The periodic signal that the potential changes with time is transmitted to the high-speed ADC and converted into a digital pulse signal II, and the digital pulse signal II is filtered by a digital filter to obtain a digital pulse signal III, and the digital pulse signal III is then passed through a peak and valley detection algorithm to obtain a digital pulse signal IV; if figure 1 As shown, digital pulse signal IV generates digital pulses at π of phase a, 2π / 3 of phase b, and π / 3 of phase c.

[0023] 2c. The digital pulse is used for phase angle compensation in the CPU of the DSPIC microcontroller to obtain the commutation angle of the BLDC motor.

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Abstract

The invention provides a BLDC motor phase detection method based on back electromotive force wave crests and wave troughs. The method is a peak detection method using motor electromotive force, an accurate phase-change position is acquired, the comparison with neutral point voltage is avoided, and filtering detection is carried out on the back electromotive force phase voltage of a BLDC motor. Due to the fact that the back electromotive force phase voltage is closely related with the relative positions of a rotor and a stator of the BLDC motor, the phase-change angle of the BLDC motor can be calculated in a compensating manner through the phase detection of the back electromotive force wave crests and wave troughs. The BLDC motor phase detection method based on the back electromotive force wave crests and wave troughs provided by the invention has the advantage of high disturbance rejection ability, the defect of phase-change angle miscalculation caused by neutral point phase-position disturbance does not exist, excessive zero crossing point detection error caused by neutral point shaking in a certain specific environment is avoided, and accurate basis is provided for phase-change operation of the BLDC motor.

Description

technical field [0001] The invention belongs to the field of phase detection of a sensorless BLDC motor, and in particular relates to a phase detection method of a BLDC motor based on back EMF peaks and valleys. Background technique [0002] BLDC motors directly determine the rotor position through sensors such as Hall sensors or photoelectric encoders. However, in certain environments, such as liquid or high temperature, high pressure, and strong corrosion, the accuracy of the sensor is affected, and even cannot work properly. If no sensor is used, that is, in the case of no position sensor, only by obtaining the back EMF signal inside the BLDC motor, and then after a certain algorithm processing, the rotor position is derived, which will have advantages that the sensor control mode does not have. [0003] At present, the relatively mature and widely used back EMF detection methods mainly include: [0004] 1) The state observer method estimates the rotor position through t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02P6/182
CPCH02P6/182
Inventor 雷艳华何朝晖吉方张日升王兴华刘广民
Owner INST OF MACHINERY MFG TECH CHINA ACAD OF ENG PHYSICS