CN112865436A

CN112865436A - Special motor and control method and control device thereof

Info

Publication number: CN112865436A
Application number: CN201911175374.6A
Authority: CN
Inventors: 孙佳男; 孔得琳; 陈文镥; 冯同; 郝双晖
Original assignee: Harbin Institute of Technology Shenzhen
Current assignee: Harbin Institute of Technology Shenzhen
Priority date: 2019-11-26
Filing date: 2019-11-26
Publication date: 2021-05-28
Anticipated expiration: 2039-11-26
Also published as: CN112865436B

Abstract

The application provides a special motor. The special motor comprises a motor body, a controller and a multi-pair-pole combined magnetoelectric encoder; the controller comprises a shell and a control module, wherein the control module is arranged in the shell and is connected with the motor body through a connecting piece; many antipodal combination magnetoelectric encoder, with the coaxial setting of motor body, including the first many antipodal magnet and the many antipodal magnet of second that coaxial annular set up, first many antipodal magnet includes m to the magnetic pole, the many antipodal magnet of second includes n to the magnetic pole, and m and n are for being greater than 2 natural numbers and each other matter. Through the motor body with many pairs of pole magnetoelectric sensor and the flexible matching of controller make control accuracy, system response speed, reliability improve greatly.

Description

Special motor and control method and control device thereof

Technical Field

The application belongs to the field of motors, and particularly relates to a special motor.

Background

An electric motor is a power source widely used in the industrial field. The motors comprise various types, and can be divided into asynchronous motors and synchronous motors according to different classification standards; an ac motor, a dc motor, and the like. In some existing systems, precise control of the position, rotation speed, and the like of a motor is required, and a servo motor system is developed. The motor is combined with a controller and an encoder, and the position of the motor is detected by the encoder and fed back to the controller, so that the closed-loop control of the motor is realized. The motor has the characteristics of high response characteristic, wide speed regulation range and the like, and is widely concerned by industrial and agricultural production.

In a servo motor system, the accuracy of the encoder directly affects the speed control and positioning accuracy of the system. At present, photoelectric encoder's application is comparatively extensive, installs it in the pivot, can pass through the cable with angle information and transmit the controller. Photoelectric encoders are classified into incremental encoders and absolute encoders.

The incremental encoder shaft rotates to drive the optical disk to rotate, the light emitted by the light-emitting element is cut into intermittent light by the grating disk and the slit of the indicating grating, and the intermittent light is received by the receiving element to output a corresponding pulse signal. The rotation direction and the pulse number are realized by a direction-finding circuit and a counter. The start of counting can be set arbitrarily. When the rotary incremental encoder rotates, pulses are output, positions are memorized through internal memory of the counting device, interference is not allowed to exist in the working process, so that the pulses are lost, otherwise, memory zero points of the counting device can be shifted, and the accuracy of the encoder is reduced.

In order to solve the drawbacks of the incremental photoelectric encoder, an absolute photoelectric encoder has appeared. The output of the absolute encoder is in one-to-one correspondence with the position, each position of the absolute encoder corresponds to a group of binary codes, and the rotation direction and the absolute position can be judged according to the change of the codes. The anti-interference performance and the data reliability are greatly improved, and the absolute encoder is more and more applied to angle and length measurement and position control of various industrial systems.

However, the photoelectric encoder has some disadvantages that are difficult to overcome. The photoelectric encoder is formed by scribing glass materials, so that the photoelectric encoder is not high in vibration resistance and impact resistance, is not suitable for severe environments such as dust and dew, and is complex in structure, positioning and assembling. The distance between the scribed lines is limited, and the code disc needs to be increased to improve the resolution, so that the miniaturization is difficult. In production, it is also necessary to ensure a high assembly precision, which directly affects the production efficiency and ultimately the cost of the product.

In order to overcome the above-mentioned disadvantages of encoders, magnetoelectric encoders for motor systems have been developed. Such an encoder includes a magnet, a magnetic induction element, and a signal processing circuit. The magnet rotates with the motor shaft, producing a varying magnetic field. The magnetic induction element induces the changed magnetic field, converts the magnetic signal into an electric signal and outputs the electric signal to the signal processing circuit. The signal processing circuit processes the electrical signal into an angular signal output. For a dc brushless motor, the magnetic poles of the magnets used in the magnetoelectric encoder are adapted to the number of magnetic poles of the dc brushless motor for normal use. The use of the magnetoelectric encoder is not so limited for the alternating-current permanent magnet synchronous motor.

The magnetic signal generator can be divided into a single-pair-pole magnetoelectric encoder, a single-multi-pair-pole combined magnetoelectric encoder and a multi-pair-pole and multi-pair-pole combined magnetoelectric encoder according to different magnetic signal generating sources of the magnetoelectric encoder. The single-multi-pair combined magnetoelectric encoder is characterized in that a multi-pair magnetic field signal source is added on the basis of the traditional single-pair magnetoelectric encoder, and the signals of the multi-pair magnets are encoded and subdivided through the signals of the single-pair magnets, so that the aim of improving the resolution ratio is fulfilled. Many antipodes and many antipodes combination formula magnetoelectric encoder become many antipodes magnet with single antipode magnet on the basis of single many antipodes combination formula magnetoelectric encoder, have improved single many antipodes combination formula magnetoelectric encoder's reliability and precision.

At the same time, the control of the motor directly affects the operation of the whole system. Therefore, a control system of the motor is receiving attention. The traditional motor generally adopts a cable mode to transmit position information to a CPU of a controller, but the traditional motor is easily interfered by electromagnetic noise in a communication process to cause information errors, has communication hysteresis, and cannot reflect the position information of a motor rotor in real time, so that the control effect of the whole system is influenced. And traditional motor all designs to single target, but just need to change the motor under the requirement that needs to accomplish the task more, can not realize the commonality, has caused huge waste.

Disclosure of Invention

The application provides a special motor using multi-pair poles and multi-pair pole combined magnetoelectric encoders, and the encoders are combined into an integrated control system to improve the control precision, response speed and reliability of the motor.

The application proposes a special motor, comprising:

a motor body;

the controller comprises a shell and a control module, wherein the control module is arranged in the shell and is connected with the motor body through a connecting piece;

many antipodal combination magnetoelectric encoder, with the coaxial setting of motor body, including the first many antipodal magnet and the many antipodal magnet of second and circuit board of coaxial annular setting, first many antipodal magnet includes m to the magnetic pole, the many antipodal magnet of second includes n to the magnetic pole, and m and n are for being greater than 2 natural numbers and each other matter.

By using the combined magnetoelectric encoder with the coprime of the pole number of the magnet, one end of the magnetic pole does not need to be aligned in the installation process, thereby simplifying the installation process; meanwhile, the encoder can be applied to working conditions of small axial size and large radial size, and the application range of the magnetoelectric encoder is expanded.

In some embodiments of the present application, the motor body is a permanent magnet synchronous motor.

In some embodiments of the present application, the first plurality of pairs of pole magnets are located on an outer ring, the second plurality of pairs of pole magnets are located on an inner ring, and m is greater than n.

In some embodiments of the present application, m and n are prime numbers.

In some embodiments of the present application, the first plurality of pairs of pole magnets are arranged with a magnetization direction that coincides with a radial or axial direction of the ring.

In some embodiments of the present application, the second plurality of pairs of pole magnets are arranged with a magnetization direction that coincides with a radial or axial direction of the ring.

In some embodiments of the present application, the circuit board includes a first set of magnetoelectric sensors thereon, disposed opposite a first plurality of pairs of pole poles; the circuit board comprises a second group of magnetoelectric sensors which are arranged opposite to the second multiple pairs of magnetic poles; the magnetic sensor comprises a third group of magnetoelectric sensors which are arranged opposite to the first or second multiple pairs of magnetic poles.

Further, the number p of the first group of magnetoelectric sensors is equal to or greater than n, and the number q of the second group of magnetoelectric sensors is equal to or greater than m.

In the above code, the first set of magnetoelectric sensors and the second set of open magnetoelectric sensors are aligned at one end.

In some embodiments of the present application, the first set of magneto-electric sensors are disposed at an angular separation of 360/2mp and the second set of magneto-electric sensors are disposed at an angular separation of 360/2 nq.

Drawings

The present application is described in detail below with reference to the attached drawings. The foregoing and other aspects of the present application will become more apparent and more readily appreciated from the following detailed description, taken in conjunction with the accompanying drawings. In the drawings:

fig. 1 shows a structural composition schematic diagram of a special motor according to an exemplary embodiment of the present application.

FIG. 2A illustrates a plan view of a multi-pair pole combined magneto-electric encoder magnet structure according to an example embodiment of the present application.

FIG. 2B illustrates a perspective view of a multi-pair pole combination magnetoelectric encoder magnet structure according to an example embodiment of the present application.

Fig. 3 shows a special motor operating diagram according to an exemplary embodiment of the present application.

Fig. 4 illustrates a special motor control system schematic according to an example embodiment of the present application.

Fig. 5 shows a flow chart of a special motor control method according to an example embodiment of the present application.

Fig. 6 shows a first sub-flowchart of a special motor control method according to an example embodiment of the present application.

Fig. 7 shows a second sub-flowchart of a special motor control method according to an example embodiment of the present application.

Fig. 8 shows a block diagram of a special motor control device according to an example embodiment of the present application.

Fig. 9 shows a special motor control device data processing module sub-block diagram according to an example embodiment of the present application.

Detailed Description

The following detailed description of embodiments of the present application refers to the accompanying drawings.

The embodiments/examples described herein are specific embodiments of the present application and are intended to be illustrative and exemplary of the concepts of the present application and should not be construed as limiting the embodiments of the present application and the scope of the present application. In addition to the embodiments described herein, those skilled in the art will be able to employ other technical solutions which are obvious based on the disclosure of the claims and the specification of the present application, and these technical solutions include technical solutions which make any obvious replacement or modification of the embodiments described herein, and all of which are within the scope of the present application.

The inventor finds that under the condition that the radial dimension of the motor is larger and the axial dimension is smaller, the combined magnetoelectric encoder adopting the existing single-pole and multi-pole combination mode can cause the radial dimension of the magnet of the single-pole pair to be larger and the axial dimension to be smaller. During processing and magnetizing or using, the single-pole magnet pair is easy to damage, and the processing and application of the encoder are influenced. For multiple pairs of poles, because the number of pole pairs within a magnet's circumference is relatively large, the size of each pole is small and easier to machine and use than a single pair of pole magnets. In another existing multi-pole and multi-pole combined encoder, the number of the magnetic pole pairs usually differs by 1, and the initial position alignment is required during installation, so that the operation is inconvenient.

The invention provides a novel combined encoder applied to a motor, namely, on the basis of the original combined encoder, the original mode of combining single antipode and multiple antipodes is changed into the mode of combining magnets with two prime numbers and pole pairs to realize the magnetic pole division of multiple antipodes. When the encoder is integrated with the motor body, the encoder can be installed without initial position alignment, and the operation is simple and convenient. The motor body, the novel encoder and the control system are integrated into a whole, so that the control precision and the response speed of the motor can be further improved.

As shown in fig. 1, the special motor includes: the motor comprises a motor body 1, a controller 8 and a multi-pair-pole combined magnetoelectric encoder 7. The controller 8 comprises a control module 5 and a housing 6.

The control module 5 is arranged in the shell 6 and is connected with the motor body 1 through a connecting piece. And the multi-pair-pole combined magnetoelectric encoder 7 is arranged in the shell 6 and is coaxially arranged with the motor body 1. The multi-pair-pole combined magnetoelectric encoder 7 is arranged in front of the motor body 1 and between the motor body 1 and the control module 5, and can also be arranged behind the control module 5 or behind the control module 5.

The multi-pair pole combined magnetoelectric encoder 7 comprises a first multi-pair pole magnet 2 and a second multi-pair pole magnet 3 which are coaxially and annularly arranged, and a circuit board 4. The first multi-pair of pole magnets includes m pairs of poles, the second multi-pair of pole magnets includes n pairs of poles, and m and n are natural numbers greater than 2 and are coprime to each other.

According to an exemplary embodiment of the present application, the motor body 1 is a permanent magnet synchronous motor, and includes a stator, a rotor, a rotating shaft, magnetic steel, a winding, and a series of connecting members. The first and second pairs of

polar magnets

2 and 3 and the circuit board 4 operate simultaneously. The first and second pairs of

polar magnets

2 and 3 rotate together with the motor shaft.

Fig. 2A, 2B illustrate plan and perspective views of a multi-pair pole combined magnetoelectric encoder magnet structure according to an example embodiment of the present application.

As shown in fig. 2A and 2B, the multi-pair pole combined encoder magnet structure includes: a first and a second multi-pair of

polar magnets

11, 12 arranged coaxially and annularly in a first spatial plane. The first multi-pole magnet 11 includes m pairs of magnetic poles, and the second multi-pole magnet 12 includes n pairs of magnetic poles, where m and n are natural numbers greater than 2 and are relatively prime to each other. For example, according to some embodiments, m and n are prime numbers. As shown in fig. 2A and 2B, in the present embodiment, m is 5 and n is 3, but the present application is not limited thereto.

When encoding is performed with the encoder magnet, the motor rotor, for example, can be positioned according to the encoding result. However, if the coding has repetition, the positioning cannot be performed efficiently. In order to eliminate or reduce the repeated condition, the magnet structure with the multiple pairs of mutual-prime poles is adopted, the repeated coding condition can be eliminated by combining the magnetoelectric sensor, and the detection precision is improved.

Further, the first multiple pairs of polar magnets 11 are located on the outer ring, the second multiple pairs of polar magnets 12 are located on the inner ring, and the number m of opposite poles of the first multiple pairs of polar magnets is greater than the number n of opposite poles of the second multiple pairs of polar magnets. This is because the diameter of the outer ring is larger than that of the inner ring, and the number of magnets of the outer ring is larger than that of the inner ring in order to make the size of the magnets uniform.

According to some embodiments, the first plurality of pairs of polar magnets 11 may be arranged with a magnetization direction coinciding with the radial or axial direction of the ring. In the embodiment shown in fig. 2A, 2B, the magnetization direction of the first multiple pairs of pole magnets 11 is set to the axial direction. The second plurality of pairs of pole magnets 12 may also be arranged with a magnetization direction that coincides with the radial or axial direction of the ring. In the embodiment shown in fig. 2A, 2B, the magnetization direction of the second multi-pair pole magnet 12 is set to the axial direction. The magnetization direction is not limited to this, and the magnetization direction of the first multi-pair magnet may be set to the radial direction, the magnetization direction of the second multi-pair magnet may be set to the axial direction, or the magnetization directions of both the first multi-pair magnet and the second multi-pair magnet may be set to the radial direction.

In the encoder magnet structure shown in fig. 2A and 2B, the first and second multiple-pair-

pole magnets

11 and 12 may be formed by adhering multiple magnetic poles, but are not limited thereto. The magnet according to this application can adopt neodymium iron boron permanent magnet material to make, and a plurality of magnets can be attached on the base plate, or directly attached for example at the pivot tip. According to some embodiments, a plurality of magnets may be disposed on the support plate. The support plate may be an annular structure and a second plurality of pairs of pole magnets 12 may be disposed along a circumferential normal direction of the bore thereof. The first multi-pair pole magnet 11 is fixed to the annular surface of the support plate. The fixing means may be an adhesive bond.

And in the working process of the encoder, the magnetoelectric sensor is arranged on the circuit board. The position signals of the first multiple pairs of polar magnets 11 and the second multiple pairs of polar magnets are collected through a magnetoelectric sensor, and the angle information of the rotating shaft of the motor is output.

According to a second aspect of the present application, there is provided a control method of the special motor. Before determining the control method of the special motor, a clear understanding of its working principle is required.

As shown in fig. 3, during the operation of the special motor, the encoder detects the rotation angle of the motor shaft of the motor, and transmits the detected voltage signal to the controller. The angle or position of rotation of the motor shaft is obtained through processing by the controller. Six paths of PWM signals are calculated and output through the control system, the inverter module is driven to work and output three-phase voltage signals, and therefore the motor is driven to work, and accurate control over the motor is achieved.

According to the working principle of the special motor, the control principle can be obtained. Fig. 4 illustrates a special motor control system schematic according to an example embodiment of the present application.

As shown in fig. 4, first, the upper computer sends an angle command of the motor to the system. The system outputs an angle error signal to enter a PID controller by comparing the command with the angle information detected by the magnetoelectric sensor. The speed command information is output by calculation.

Then, the system compares the differential of the speed command and the angle command detected by the magnetoelectric sensor, and outputs a speed error to enter a PID controller. Through calculation, a q-axis current control command I is output_{q_ref}. The upper computer sends a d-axis current instruction I simultaneously_{d_ref}。

The current sensors respectively detect three-phase current signals I_{a_fb}、I_{b_fb}、I_{c_fb}Outputs d-axis and q-axis current feedback signals I through 3-2 conversion_{d_fb}、I_{q_fb}And compared with the command signal. Generating d-axis and q-axis current error signals I_{d_err}、I_{q_err}. Respectively output to a PID controller for calculation and output a voltage instruction U_{d_ref}、U_{q_ref}。

The 3-2 transformation calculation formula is shown in 3-1. This formula is as follows_{a_fb}、I_{b_fb}、I_{c_fb}Converting three feedback current signals into feedback current signals I of d and q axes_{d_fb}、I_{q_fb}. In the formula [ theta ]_eIs the electrical angle of the motor, where θ_e＝p×θ_r. p is the number of pole pairs, theta, of the motor_rThe mechanical angle of the motor is measured by a magnetoelectric sensor.

Then three paths of voltage signals U are output through 2-3 conversion_{a _ duty cycle}、U_{b _ duty cycle}、U_{c _ duty cycle}And the PWM module generates six paths of PWM waves and inputs the six paths of PWM waves to the inverter module.

The 2-3 transformation calculation formula is shown in fig. 3-2. The formula instructs the voltage of d and q axes to be U_{d_ref}、 U_{q_ref}Three-phase voltage signal U converted into three paths_{a _ duty cycle}、U_{b _ duty cycle}、U_{c _ duty cycle}. In the formula [ theta ]_eAs an electric motorElectrical angle of (d).

Finally, the inverter realizes the on-off of the switch through the input PWM wave, thereby outputting three voltage signals U_a、U_b、U_cAnd the motor is driven, so that the precise control of the motor is realized.

For the special motor in the present invention in which the motor body, the magnetoelectric encoder, and the control module are integrated, based on the above-described working principle and system control principle, the control method of the special motor is described below to match therewith.

As shown in fig. 5, the special motor control method includes:

s1: the current sensor collects an input current signal of the motor body;

s2: the magnetoelectric sensor detects and outputs angle information of the motor body;

s3: receiving data, processing the data and outputting a control signal;

s4: receiving a control signal and outputting a voltage signal to the motor body.

As shown in fig. 6, the angle information S2 of the motor body detected and output by the magnetoelectric sensor includes:

s21: the method comprises the steps that rotating magnetic field information generated by driving a magnet when a motor rotates is collected through a Hall device;

s22: signal amplification and conversion are carried out through an amplifier and an A/D converter;

s23: calculating the actual rotation angle of the motor through a table look-up and a calculation program;

s24: carrying out error compensation;

s25: and outputting the actual rotation angle information of the motor after the calculation is finished.

As shown in fig. 7, the receiving data, performing data processing, and outputting a control signal S3 includes:

s31: receiving a current signal detected by a current sensor, and outputting the current signal after A/D sampling;

s32: receiving and outputting information representing the angle of the motor output by the magnetoelectric sensor;

s33: receiving the instruction signal and the rotation angle information of the motor shaft, and calculating to obtain and output a current instruction;

s34: receiving a current instruction and a current signal, calculating to obtain a duty ratio control signal of the three-phase voltage and outputting the duty ratio control signal;

s35: and receiving the three-phase voltage duty ratio control signals and generating six-circuit PWM signals.

As shown in fig. 8, the control device includes a current sensor module S51, a magneto-electric sensor module S52, a data processing module S53, and a motor driving module S54.

The current sensor module S51 is used for collecting an input current signal of the motor body;

the magnetoelectric sensor module S52 is used for detecting and outputting the angle information of the motor body;

the data processing module S53 is used for receiving data, performing data processing, and outputting a control signal;

the motor drive module 54 is configured to receive the control signal and output a voltage signal to the motor body.

As shown in fig. 9, in the above control apparatus, the data processing module S53 includes a sensing signal processing submodule S531, a mechanical loop control submodule S532, an electric current loop control submodule S533, and a PWM control signal generating submodule S534.

The sensing signal processing submodule S531 is configured to: receiving a current signal detected by a current sensor, and outputting the current signal after A/D sampling; and receiving and outputting information which is output by the magnetoelectric sensor and represents the angle of the motor.

And the mechanical ring control submodule S532 is used for receiving the instruction signal and the rotation angle information of the motor shaft, calculating to obtain a current instruction and outputting the current instruction.

The current loop control submodule S533 is configured to calculate to obtain and output a duty ratio control signal of the three-phase voltage according to the received current instruction and the current signal.

The PWM control signal generation submodule S534 is configured to receive the three-phase voltage duty control signals and generate a PWM signal having six paths.

It should be noted that the embodiments described above with reference to the drawings are only for illustrating the present invention and do not limit the scope of the present invention. It will be understood by those skilled in the art that various modifications and equivalent arrangements can be made without departing from the spirit and scope of the invention. Furthermore, unless the context indicates otherwise, words that appear in the singular include the plural and vice versa. Additionally, all or a portion of any embodiment may be utilized with all or a portion of any other embodiment, unless stated otherwise.

Claims

1. a special motor, is characterized in that, comprises:

motor body;

a controller, comprising a casing and a control module, the control module is arranged in the casing and is connected to the motor body through a connector;

A multi-pole combined magnetoelectric encoder, which is coaxially arranged with the motor body, and includes a first multi-pole magnet, a second multi-pole magnet, and a circuit board arranged in a coaxial ring. The first multi-pole magnet includes m pairs of magnetic poles, the second multi-pole magnet includes n pairs of magnetic poles, m and n are natural numbers greater than 2 and are relatively prime to each other.

2 . The special motor according to claim 1 , wherein the motor body is a permanent magnet synchronous motor. 3 .

3 . The special motor according to claim 1 , wherein the first multiple pairs of pole magnets are located in the outer ring, the second multiple pairs of pole magnets are located in the inner ring, and m is greater than n. 4 .

4. The special motor according to claim 1, wherein m and n are prime numbers.

5 . The special motor according to claim 1 , wherein the first plurality of pairs of pole magnets are arranged so that the magnetization direction is consistent with the radial direction or the axial direction of the ring. 6 .

6 . The special motor according to claim 1 , wherein the second plurality of pairs of pole magnets are arranged so that the magnetization direction is consistent with the radial direction or the axial direction of the ring. 7 .

7 . The special motor according to claim 1 , wherein the circuit board includes a first group of magnetoelectric sensors, which are arranged opposite to the first multi-pole pairs of magnetic poles, and the circuit board includes a second group of magnetoelectric sensors. 8 . The sensor, which is arranged opposite to the second multi-pole pair of poles, includes a third group of magneto-electric sensors, which is arranged opposite to the first or second multi-pole pair of poles.

8. The special motor according to claim 7, wherein the number p of the first group of magnetoelectric sensors is equal to or greater than n, and the number q of the second group of magnetoelectric sensors is equal to or greater than m.

9. The special motor of claim 8, wherein the first set of magnetoelectric sensors and the second set of magnetoelectric sensors are aligned at one end.

10 . The special motor according to claim 8 , wherein the first group of magnetoelectric sensors is arranged at an interval angle of 360/2mp, and the second group of magnetoelectric sensors is arranged at an interval angle of 360/2nq. 11 .