Method for detecting motor speed and motor rotor position of air conditioner outdoor unit

Abstract

The invention relates to a rotation speed and position detecting method for an outdoor fan of a DC permanent magnet synchronous motor (PMSM), belongs to the technical field of obtaining rotation speed and position of the motor, and aims at solving the problems that rotation speed and position detection for the outdoor fan of an air conditioner at present is inaccurate, and a concrete method for detecting forward and backward rotation of the motor lacks. The method comprises the following steps that a phase voltage value between a three-phase back electromotive force of the motor and a central point is obtained; According to a time difference between first zero-crossing time and second zero-crossing time of the phase voltage value of the three-phase back electromotive force, angles corresponding to the zero-crossing time of the phase voltage value of the three-phase back electromotive force is obtained at the same time, and position information of a motor rotor is further obtained; and the rotation frequency of the motor is calculated via phase-locked loop control. The method is suitable for the air conditioner.

Description

technical field

[0001] The invention relates to air-conditioning control technology, in particular to a method for detecting the speed and position of an outdoor fan of a permanent magnet synchronous DC motor. Background technique

[0002] The permanent magnet synchronous DC brushless motor has a sine wave back electromotive force. When the permanent magnet synchronous DC brushless motor is used as the driving part of the outdoor fan of the air conditioner, due to sea breeze and other reasons, the outdoor fan motor may be in positive position before the air conditioner is started. Direction or reverse direction rotation, the controller needs to detect the position, speed and direction of rotation of the motor, based on which the corresponding start-up control is carried out in a timely manner according to the operation of the motor, so as to achieve the purpose of correctly controlling the operation of the motor.

[0003] The patent application with the patent application nu...

Examples

Embodiment

[0019] The present invention solves its technical problem, and the technical solution adopted is: the single-chip microcomputer MCU acquires the phase voltage value between the three-phase electromotive force U / V / W of the motor and its center point N, and further according to the phase voltage of the three-phase electromotive force U / V / W The zero-crossing time T between two values 60 And the corresponding motor rotor position θ when the phase voltage crosses zero 60N , θ 60N ∈[0,60,120,180,240,300], get the motor speed and its position.

[0020] Due to θ 60N at T 60 Time, will not change in time, in order to obtain high-precision motor speed and rotor position, special use of phase-locked loop control, through the phase-locked loop adjustment.

[0021] figure 1 It is a phase-locked loop control block diagram. When the three-phase electromotive force has a zero-crossing, record the time T that has elapsed since the last zero-crossing occurred at this time. 60 , at the sam...

technical field

[0001] The invention relates to air-conditioning control technology, in particular to a method for detecting the speed and position of an outdoor fan of a permanent magnet synchronous DC motor. Background technique

[0002] The permanent magnet synchronous DC brushless motor has a sine wave back electromotive force. When the permanent magnet synchronous DC brushless motor is used as the driving part of the outdoor fan of the air conditioner, due to sea breeze and other reasons, the outdoor fan motor may be in positive position before the air conditioner is started. Direction or reverse direction rotation, the controller needs to detect the position, speed and direction of rotation of the motor, based on which the corresponding start-up control is carried out in a timely manner according to the operation of the motor, so as to achieve the purpose of correctly controlling the operation of the motor.

[0003] The patent application with the patent application nu...

Examples

Embodiment

[0019] The present invention solves its technical problem, and the technical solution adopted is: the single-chip microcomputer MCU acquires the phase voltage value between the three-phase electromotive force U / V / W of the motor and its center point N, and further according to the phase voltage of the three-phase electromotive force U / V / W The zero-crossing time T between two values 60 And the corresponding motor rotor position θ when the phase voltage crosses zero 60N , θ 60N ∈[0,60,120,180,240,300], get the motor speed and its position.

[0020] Due to θ 60N at T 60 Time, will not change in time, in order to obtain high-precision motor speed and rotor position, special use of phase-locked loop control, through the phase-locked loop adjustment.

[0021] figure 1 It is a phase-locked loop control block diagram. When the three-phase electromotive force has a zero-crossing, record the time T that has elapsed since the last zero-crossing occurred at this time. 60 , at the sam...

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