CN113014153A

CN113014153A - Control system, method and device of three-phase brushless direct current motor

Info

Publication number: CN113014153A
Application number: CN202110186849.2A
Authority: CN
Inventors: 璩红宝; 唐树龙
Original assignee: Saikaer Beijing Industrial Technology Co ltd
Current assignee: Saikaer Beijing Industrial Technology Co ltd
Priority date: 2021-02-08
Filing date: 2021-02-08
Publication date: 2021-06-22

Abstract

The invention relates to an automatic control technology and discloses a control system, a control method and a control device of a three-phase brushless direct current motor for an elevator and a storage medium. The control system includes: the control system adopts a direct current power supply to supply power, the operation unit provides a motor control signal to the main control unit, the main control unit outputs a pulse control signal to the motor driving unit, and the motor driving unit converts the pulse signal into a pulse signal and adjusts the current of each phase winding of the three-phase brushless motor to control the rotation of the motor. The invention adopts the outer rotor three-phase brushless DC motor, reduces the volume and the weight of the whole system and lowers the requirement on the motor processing technology; and a non-contact magnetic coding chip is further adopted to detect the rotating speed of the motor, so that the running stability of the system is improved.

Description

Control system, method and device of three-phase brushless direct current motor

Technical Field

The invention relates to the field of automatic control, in particular to a control system, a method and a device for a three-phase brushless direct current motor for driving a lifter.

Background

When the three-phase brushless direct current motor is an inner rotor direct current motor, the rotor is arranged in the stator, the stator is provided with a three-phase armature winding, and the rotor is provided with a rotor winding or a permanent magnet. The position of each phase of armature winding of the stator relative to the rotor winding or the permanent magnet is sensed by a position sensor on the stator in an electronic or electromagnetic mode, and the position sensor outputs signals by utilizing the position sensor, and the corresponding power switch tubes in an inverter circuit for supplying power to the armature winding are driven according to certain logic through an electronic commutation circuit, so that the armature winding is sequentially and continuously electrified, a rotating magnetic field is formed in the space between the stator and the rotor, and the rotating magnetic field pulls the rotor to rotate, thereby controlling the motor to rotate.

The application of the lifter in the current market is gradually increased, and the lifter is commonly used in the fields of personnel or equipment transportation, high-altitude equipment maintenance, field climbing, emergency rescue and the like. When the lifter is driven by an AC asynchronous motor, the lifter needs to be powered by an AC power supply, can be used only in occasions where the AC power supply is provided, and is not portable, so that the lifter is not very inconvenient to use. When the lifter driven by the direct current motor is adopted, an inner rotor three-phase brushless direct current motor with a Hall sensor is generally adopted, when the inner rotor three-phase brushless direct current motor is assembled, 3 Hall sensors are embedded in corresponding angles in the inner rotor three-phase brushless direct current motor, and position detection is carried out on a motor rotor for generating a phase change signal and a motor speed detection signal required by controlling the motor. The installation of the Hall sensor puts higher requirements on the processing technology of the three-phase brushless direct current motor, and also brings part of unstable factors into a control system of the motor. Meanwhile, the internal rotor three-phase brushless direct current motor is large in size and weight, so that the internal rotor three-phase brushless direct current motor is inconvenient to carry.

Disclosure of Invention

In order to overcome the technical problems, the application provides a control system, a method, a device and a storage medium of a three-phase brushless direct current motor for an elevator. The lifter is driven by the three-phase brushless direct current motor, so that the power consumption, the weight and the volume of a product are reduced on the basis of the same performance, the motor is subjected to rotating speed detection, the detected rotating speed is introduced into a control system for closed-loop control, and the instability of the system caused by the absence of a speed feedback system is avoided.

The present application firstly provides a control system of a three-phase brushless dc motor, the three-phase brushless dc motor is used for driving a lifter, wherein, the three-phase brushless dc motor includes a stator and a rotor, the stator is disposed in the rotor, a three-phase armature winding is disposed in the stator, the control system includes: the device comprises an operation unit, a main control unit, a motor driving unit and a motor rotating speed detection unit; wherein:

the operation unit is used for receiving an operation signal of the lifter, generating a motor control signal according to the operation signal and sending the motor control signal to the main control unit, wherein the motor control signal comprises a motor rotating speed control signal and a motor rotating direction control signal;

the motor rotating speed detection unit is used for detecting the rotating speed of the rotor and feeding a rotating speed detection signal back to the main control unit;

the main control unit obtains a motor target rotating speed according to the motor rotating speed control signal, obtains a motor feedback rotating speed according to the rotating speed detection signal, obtains a rotating speed variation controlled by the motor according to the motor target rotating speed and the motor feedback rotating speed, determines a motor rotating direction according to the motor rotating direction control signal, generates a pulse control signal for controlling the three-phase brushless direct current motor according to the motor rotating direction and the rotating speed variation, and sends the pulse control signal to the motor driving unit;

and the motor driving unit converts a direct current power supply into three-phase alternating current required by the three-phase armature winding during working according to the received pulse control signal so as to enable the three-phase brushless direct current motor to reach the target rotating speed of the motor.

On one hand, the motor rotating speed detection unit comprises a magnetic angle encoder, the magnetic angle encoder comprises a magnetic encoding chip and a detection magnetic pole, the detection magnetic pole is coaxially assembled with the rotor and synchronously rotates with the rotor, and the magnetic encoding chip induces the rotation change of the detection magnetic pole to generate the rotating speed detection signal. A

In another aspect, the motor drive unit includes: pulse width modulation PWM control circuit, inverter circuit, back electromotive force detection circuitry and converting circuit, wherein:

the inverter circuit comprises 6 bridge circuits, each bridge circuit is provided with a power switch tube, and each power switch tube is correspondingly provided with a driving unit;

the counter electromotive force detection circuit detects three-phase counter electromotive force corresponding to a three-phase armature winding of the three-phase brushless direct current motor, generates three counter electromotive force signals and outputs the three counter electromotive force signals to the conversion circuit;

the conversion circuit obtains 6 paths of phase-change signals according to the three-phase back electromotive force signals and sends the signals to the PWM control circuit;

the PWM control circuit generates 6 paths of PWM chopping signals according to the pulse control signals and the 6 paths of commutation signals, each path of PWM chopping signal is respectively sent to the driving unit of one of the power switching tubes, and the driving unit of each path of power switching tube controls the on-time and the off-time of the power switching tube according to the received PWM chopping signals, so that the direct-current power supply is sequentially loaded on the three-phase armature winding to generate three-phase alternating-current for driving the motor to rotate.

On the other hand, the motor rotating speed control signal output by the operation unit is an analog quantity voltage signal output by the operation unit in response to the operation mechanical action; the motor rotation direction control signal comprises two paths of digital quantity signals, wherein one path of digital quantity signal is used for indicating that the motor rotation direction is clockwise rotation, and the other path of digital quantity signal is used for indicating that the motor rotation direction is anticlockwise rotation.

In another aspect, the generating a pulse control signal for controlling the three-phase brushless dc motor according to the motor rotation direction and the rotation speed variation specifically includes:

determining the pulse width according to the rotation direction of the motor and the rotation speed variation;

and generating a pulse control signal for controlling the motor according to the pulse width.

Furthermore, the main control unit determines the rotation speed variation Δ no by using a PID proportional integral derivative control method, and when the motor rotation direction control signal indicates a working state in which the three-phase dc brushless motor drives the elevator to ascend:

when the motor rotation direction control signal indicates the working state that the three-phase direct current brushless motor drives the elevator to descend:

wherein: wherein ni represents a target rotation speed, nc represents a motor feedback rotation speed, kp represents a proportional coefficient, ki represents an integral time constant, kd1 and kd2 represent differential time constants, kd1> kd2, and Ts is a lag or lead time parameter, the absolute value of which is proportional to the ratio of a feedback signal sampling period Ta to a PID control adjustment period Tc.

Furthermore, the rotation directions of the motor include clockwise rotation and counterclockwise rotation directions, when one rotation direction is in the clockwise rotation direction, the pulse width range of the pulse control signal is a first range, when the other rotation direction is in the counterclockwise rotation direction, the pulse width range of the pulse control signal is a second range, and the first range and the second range are different and do not overlap.

Furthermore, the operation unit is also used for sending a motor control signal for indicating the motor to stop running according to the operation of stopping the elevator;

the main control unit generates a pulse control signal with a pulse width of T0 when receiving the motor control signal for indicating the motor to stop running, and the motor driving unit performs braking control on the three-phase DC brushless motor when receiving the pulse control signal with the pulse width of T0;

one of the first range and the second range is greater than or equal to Tmin and less than T0, and the other is greater than T0 and less than or equal to Tmax, and the Tmin is greater than zero.

Determining the pulse width according to the rotation direction of the motor and the rotation speed variation, specifically comprising:

when the motor rotation direction is a first rotation direction for driving the elevator To ascend, the pulse width To of the pulse control signal is T0- Δ To, and Δ To is Q1 Δ no, and Q1 represents a ratio of a pulse width range of the motor pulse control signal To a rotation speed range of the motor when the motor rotates in the first rotation direction;

when the motor rotation direction is a second rotation direction for driving the elevator To ascend, the pulse width To of the pulse control signal is T0+ Δ To, and Δ To is Q2 Δ no, and Q2 represents a ratio of a pulse width range of the motor pulse control signal To a rotation speed range of the motor when the motor rotates in the second rotation direction;

the first rotating direction is a clockwise rotating direction, the second rotating direction is an anticlockwise rotating direction, or the first rotating direction is an anticlockwise rotating direction, and the second rotating direction is a clockwise rotating direction.

Further, the control system may further include: the brake driving unit responds to a brake control signal of the main control unit, controls the brake unit to act, and brakes or releases the brake of the three-phase brushless direct current motor; wherein:

the main control unit is further used for sending a brake releasing control signal to the brake driving unit when the rotation speed variation delta no reaches a set value when the rotation direction of the three-phase brushless DC motor is the rotation direction for driving the elevator to ascend, and the brake driving unit responds to the brake releasing control signal to control the brake unit to release the brake.

More and then control system can also include temperature detecting element for detect the temperature when the brushless DC motor moves, and to main control unit feedback temperature detected signal, main control unit carries out temperature control to three-phase brushless DC motor according to the temperature detected signal of feedback, wherein, temperature detecting element includes full-bridge sampling circuit and amplifier circuit, the temperature detected signal warp of sampling circuit sampling is given after amplifier circuit enlargies the transmission to main control unit, wherein:

the full-bridge sampling circuit includes temperature sensor and three resistance, temperature sensor installs on the stator, wherein temperature sensor is three-way compensation nature temperature sensor, three-phase complementary sensor includes temperature sensing resistance and three pin, is connected with temperature sensing resistance between wherein two pins, the transmission line resistance value of two pins equals, third pin ground connection in the three pin.

The embodiment of the present application further provides a control method for the foregoing control system, including the following steps:

obtaining a motor target rotating speed and a motor feedback rotating speed of a three-phase brushless direct current motor for driving the elevator;

and determining the rotation speed variation delta no by adopting a PID (proportion integration differentiation) control method, and when the motor rotation direction control signal indicates that the three-phase direct-current brushless motor drives the elevator to ascend, determining the rotation speed variation delta no by adopting the PID control method:

when the motor rotation direction control signal indicates that the three-phase direct current brushless motor drives the working state that the elevator descends:

wherein: wherein ni represents a target rotating speed, nc represents a motor feedback rotating speed, kp represents a proportional coefficient, ki represents an integral time constant, kd1 and kd2 represent differential time constants, kd1> kd2, and Ts is a lag or lead time parameter, and the absolute value of the lag or lead time parameter is in direct proportion to the ratio of a feedback signal sampling period Ta to a PID control adjustment period Tc;

and generating a pulse control signal for controlling the three-phase brushless direct current motor according to the rotation direction of the motor and the rotation speed variation, and sending the pulse control signal to a motor driving unit of the three-phase brushless direct current motor.

And to provide a control device of the aforementioned control system, comprising:

an obtaining unit for obtaining a motor target rotation speed and a motor feedback rotation speed of a three-phase brushless direct current motor driving the elevator;

the determining unit is used for determining the rotating speed variation delta no by adopting a PID (proportion integration differentiation) control method, and when the motor rotating direction control signal indicates that the three-phase DC brushless motor drives the elevator to ascend, the determining unit is used for:

and the sending unit is used for generating a pulse control signal for controlling the three-phase brushless direct current motor according to the rotation direction of the motor and the rotation speed variation and sending the pulse control signal to the motor driving unit of the three-phase brushless direct current motor.

The embodiment of the present application further provides a computer-readable storage medium, in which at least one computer program is stored, and the computer program is loaded and executed by a processor to implement the operations performed by the foregoing control methods.

The outer rotor motor is considered in this application and the bigger advantage of torque under with the volume condition, adopts outer rotor DC brushless motor drive riser. In order to overcome the defect that an outer rotor motor with large rotational inertia is unstable in a high-speed control system, a motor speed detection unit suitable for the outer rotor is further adopted, for example, a magnetic encoder replaces a Hall sensor to acquire the rotational speed of the motor, and the speed closed-loop control of a control system is realized. Compared with the existing AC motor, the external rotor three-phase brushless DC motor is adopted, the DC can be used as a working power supply, and the storage battery is adopted for supplying power, so that the motor is very conveniently used in various scenes, especially under the situations of emergency rescue, field exploration and the like without an AC power supply. And in addition, compared with an alternating current motor and an inner rotor brushless direct current motor, the outer rotor brushless direct current motor has the characteristics of small volume and large torque, and is convenient to install and carry.

Furthermore, in the embodiment of the application, according to the indicated target rotating speed of the motor and the detected feedback rotating speed of the motor, the rotating speed variation of the motor is determined through PID operation, and the rotating speed of the motor is controlled according to the rotating speed variation of the motor. When the elevator descends, the adjustment intensity of an integral link is weakened, and a differential time constant is reduced, so that the adjustment intensity of the differential is reduced, and the system performs lead compensation control.

Furthermore, the working conditions of the lifter during dragging the load to rise and fall are different, the moment of inertia of the load is opposite to that of the motor rotor during rising, and the moment of inertia of the load is consistent with that of the motor rotor during falling. Because the rotary inertia of the motor of the outer rotor is large, different control schemes are needed when the belt load rises and falls. When the load rises, the auxiliary control of the brake unit is adopted during starting, the motor is accelerated firstly, the torque is gradually increased, the motor is waited to reach a certain torque, namely, when the rotating speed variation reaches a certain value, the brake is released, so that the motor is ensured to have a certain torque during starting, and the load is prevented from sliding downwards due to inertia. When the load is reduced, the reverse torque is utilized for control during starting, the motor gives the maximum reverse torque after being rapidly started, and the brake is released at the same time, so that the motor can resist the load and rapidly slide downwards when the brake is opened. Therefore, the shaking caused by the rotational inertia of the rotor of the motor during the descending is counteracted, and the stability of the system is ensured.

Drawings

Fig. 1 is a schematic block diagram of a control system of a three-phase brushless dc motor according to an embodiment of the present disclosure;

fig. 2 is a functional diagram of a control system of a three-phase brushless dc motor according to an embodiment of the present application;

fig. 3 is a block diagram of power conversion in the control system according to an embodiment of the present disclosure;

FIG. 4a is a diagram illustrating an exemplary waveform of a motor pulse control signal in an embodiment of the present application;

FIG. 4b is a diagram illustrating an exemplary waveform of a stop signal in a motor pulse control signal according to an embodiment of the present application;

FIG. 4c is a diagram illustrating an exemplary waveform of a clockwise rotation signal in a motor pulse control signal according to an embodiment of the present application;

FIG. 4d is an exemplary diagram of a counter-clockwise rotation signal in the motor pulse control signal according to an embodiment of the present application;

FIG. 4e is a schematic diagram of two ranges of pulse widths in different rotation directions of a motor pulse control signal according to an embodiment of the present application;

FIG. 5a is a schematic diagram of a back electromotive force voltage signal waveform of the motor according to the embodiment of the present application;

FIG. 5b is a schematic diagram of a phase-change signal waveform in the embodiment of the present application;

FIG. 5c is a schematic diagram of a PWM control signal waveform of the motor according to the embodiment of the present application;

FIG. 6 is a schematic diagram illustrating a mounting principle of a contactless magnetic encoding chip in an embodiment of the present application;

FIG. 7a is a schematic diagram of a rotational speed feedback signal of a contactless magnetic coding chip when phase A is ahead of phase B in the embodiment of the present application;

FIG. 7B is a schematic diagram of a non-contact magnetic encoder chip speed feedback signal when phase B is ahead of phase A in the embodiment of the present application

Fig. 8 is a diagram showing a specific example of a motor temperature detection unit in an embodiment of the present application;

fig. 9 is a functional block diagram of a control device in the embodiment of the present application.

Detailed Description

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

A typical brushless dc motor has a stator mounted on the outside and a rotor mounted inside the stator, which is called an inner rotor structure. The motor is called an external rotor motor, in which the rotor of the motor is arranged outside and the stator is arranged in the rotor. The permanent magnet is arranged on the inner diameter of the rotor shell.

External rotor motors provide several performance advantages. First, in order to accommodate the stator, the rotor of the outer rotor motor must be larger than that of the conventional dc motor. While a larger rotor means higher inertia, which helps to suppress torque ripple so that smooth operation is possible at low speeds.

Another advantage of outer rotor motors is that they can generally produce higher torque than an equally sized inner rotor application. For a given motor diameter, the air gap area of an outer rotor motor is larger than that of the inner rotor motor application, and a larger air gap produces higher torque and can accommodate more poles, increasing the magnetic flux, which increases the lever arm for torque generation. Therefore, under the condition of having similar performance characteristics, the outer rotor motor is shorter than the inner rotor motor in the axial direction, so that the motor structure is more compact and is convenient to carry and mount.

The existing lifter mostly adopts an inner rotor brushless direct current motor, and mainly considers the following two points, namely, the inner rotor brushless motor stator is outside, the frame is stable, the Hall sensor is arranged on the stator, the positioning precision is high, and the feedback signal stability is good. And the outer rotor motor stator is inside, is unsuitable to install a Hall sensor, and a control system without sensor feedback cannot be used as a speed closed loop, so that the stability is poor, the danger is improved, and other types of sensors are additionally arranged, so that the technical difficulty is improved. Secondly, considering that the rotational inertia of the inner rotor motor is low, the system is easy to reach stability in a high-speed control system (about 10000 RPM); the outer rotor motor has large rotational inertia due to the fact that the rotor of the outer rotor motor is outside, and the control difficulty is increased when the conditions such as jitter or unstable speed are easily generated for a high-speed control system.

In view of the advantages of the outer rotor direct current brushless motor, the outer rotor direct current brushless motor is adopted to drive the lifter in view of the advantage that the torque of the outer rotor direct current brushless motor is larger under the condition of the same volume. In order to overcome the defect that an outer rotor motor with large rotational inertia is unstable in a high-speed control system, a motor speed detection unit suitable for the outer rotor is further adopted, for example, a magnetic encoder replaces a Hall sensor to acquire the rotational speed of the motor, and the speed closed-loop control of a control system is realized. Compared with the existing AC motor, the external rotor three-phase brushless DC motor is adopted, the DC can be used as a working power supply, and the storage battery is adopted for supplying power, so that the motor is very conveniently used in various scenes, especially under the situations of emergency rescue, field exploration and the like without an AC power supply. And in addition, compared with an alternating current motor and an inner rotor brushless direct current motor, the outer rotor brushless direct current motor has the characteristics of small volume and large torque, and is convenient to install and carry.

In order to form speed closed-loop control, the rotating speed of the rotor needs to be detected by a motor rotating speed detection unit, and the application further considers that the magnetic angle encoder is adopted to carry out non-contact detection on the rotating position of the motor. The magnetic angle encoder comprises a magnetic encoding chip and a matched detection magnetic pole, wherein the detection magnetic pole is used for generating an external magnetic circuit, specifically, a magnet, a magnetic ring and the like made of permanent magnet materials are adopted. The detection magnetic pole is directly arranged at the tail end of the motor shaft, so that a transition connection bearing (or a coupler) required by the traditional feedback encoder is omitted, and non-contact position measurement is realized, so that the risk of encoder failure and even damage caused by mechanical shaft vibration in the motor operation process is reduced, and the motor operation stability is promoted.

The encoding means that an angular displacement or angular velocity signal of the motor can be converted into an electric pulse signal, and the rotation speed and the rotation direction of the motor can be determined by detecting the electric pulse signal. Magnetic angle encoders utilize permanent magnets and corresponding inductive elements to determine position, angle, and velocity. Magnetic angle encoders have high robustness, durability, and compactness. Magnetic angle encoders have a simple mechanical structure and higher environmental resistance than photoelectric encoders, and they can be applied to places where the installation space is very limited due to their compact size. In the magnetic angle encoder application, the magnetic encoding chip is typically comprised of a magnetic disk, inductive element and corresponding signal processing circuitry. The magnetic disk has been magnetized into a plurality of magnetic poles. Absolute position information is obtained by axial rotation of a sense pole above the sense element. The sensing elements used are typically orthogonal biaxial hall effect chips or magneto-sensitive sensors, such as magneto-resistive elements. When the magnetic disk rotates, the induction element detects the change of multipole magnetic flux uniformly arranged along the circumferential direction on the rotating magnetic disk to obtain an incremental pulse signal or an alternating magnetic flux signal, and then the incremental pulse signal or the alternating magnetic flux signal is subjected to interpolation or subdivision processing by the signal processing circuit to obtain the required absolute value resolution output.

The present application will now be described in detail with reference to specific embodiments thereof and with reference to the accompanying drawings.

Referring to fig. 1, a schematic structural diagram of a control system of a three-phase brushless dc motor 100 according to the present invention is shown, where the three-phase brushless dc motor 100 is used to drive a lifter, the three-phase brushless dc motor 100 is an outer rotor dc motor, a stator is disposed in the rotor, and a three-phase armature winding is mounted on the stator. The control system mainly includes an operation unit 101, a motor speed detection unit 102, a main control unit 103, and a motor drive unit 104. A brake driving unit 105, a motor temperature detecting unit, etc. may also be included.

The operation unit 101 is configured to control the elevator by an operator during work, the operation unit 101 may receive an operation signal of the operator for the elevator, generate a motor control signal according to the received operation signal, and send the motor control signal of the three-phase brushless dc motor 100 to the main control unit 103, where the motor control signal includes at least one of a speed setting signal and a direction setting signal, that is, a speed setting signal of the elevator or a direction setting signal of the elevator, or includes both the speed setting signal and the direction setting signal, where the speed setting signal is a motor rotation speed control signal, and the direction setting signal is a motor rotation direction control signal. The operation unit 101 is generally an operation handle of an elevator, receives a mechanical operation signal of the operation handle by using a mechanical structure, and converts the mechanical operation signal into an analog electrical signal by using an analog circuit. For example, the speed setting signal may be switched according to the pushing depth of the handle, the direction setting signal reflects whether the elevator is to be raised or lowered, and may be determined by the operating direction of the handle, such as whether the elevator is to be raised by pushing forward, lowered by pushing downward, the speed is kept constant by stopping pushing, and the like. During the operation of the elevator, the operation unit 101 generates a corresponding motor control signal according to the change of the operation signal and sends the motor control signal to the main control unit 103, and the main control unit 103 controls the phase brushless dc motor 100 for driving the elevator according to the received motor control signal control and feedback signal.

A motor speed detection unit 102, configured to detect a rotor speed of the three-phase brushless dc motor 100 during operation, and send a speed detection signal to the main control unit 103 for speed feedback;

the main control unit 102 obtains a target rotation speed of the motor according to the motor control signal of the operation unit 101, obtains a feedback rotation speed of the motor according to the rotation speed detection signal of the motor speed detection unit 102, obtains a rotation speed variation of motor control through PID calculation according to the target rotation speed of the motor and the feedback rotation speed of the motor, generates a pulse control signal according to the rotation direction and the rotation speed variation of the motor, and sends the pulse control signal to the motor driving unit 104; the pulse control signal may be used to control the motor speed, or to control the direction of rotation of the motor, depending on the circumstances. For example, during ascending or descending, the motor speed is gradually increased according to the mechanical operation of a user, so that the elevator is gradually accelerated, and only the motor speed control signal needs to be changed. For example, when the motor is lowered from the highest point, the rotation speed direction of the motor needs to be changed from rising to falling.

The motor driving unit 104 converts the dc power into three-phase ac power required for the three-phase armature windings of the three-phase brushless dc motor 100 to operate based on the PWM control principle according to the received pulse control signal.

The control system provided by the embodiment of the application is used for an outer rotor three-phase brushless direct current motor, therefore, the rotation speed detection unit 104 can adopt a non-contact magnetic angle encoder, the magnetic angle encoder comprises a magnetic encoding chip and a detection magnetic pole, the detection magnetic pole is coaxially assembled with the rotor and synchronously rotates with the rotor, and the magnetic encoding chip induces the rotation change of the detection magnetic pole to generate a rotation speed detection signal.

And a brake driving unit 105 for controlling a brake unit (installed on a rotating shaft of the three-phase brushless dc motor, not shown in the figure) to be powered on or powered off in response to a brake control signal of the main control unit 103, so as to brake or release the brake of the three-phase brushless dc motor 100 through the brake unit.

The motor temperature detection unit 106 is configured to detect a temperature of the three-phase brushless dc motor 100 during operation, and feed back a temperature detection signal to the main control unit 103, where the main control unit 103 performs temperature control on the three-phase brushless dc motor 100 according to the fed-back temperature detection signal, where the temperature control includes heat dissipation control, speed reduction or stall control during overheating, and the like.

The PID control algorithm, namely proportional, integral and derivative control algorithm, can be used for controlling the operation of the direct current motor, and in the control of the operation process of the direct current motor, a PID controller which controls according to the proportion (P), the integral (I) and the derivative (D) of the deviation is an automatic controller which is most widely applied. Based on a PID control algorithm, the driving voltage of the three-phase brushless direct current motor is controlled according to the indicated speed value, the rotating speed of the motor is enabled to reach the indicated speed value as soon as possible and the speed value is maintained. The speed variation calculated by the PID is sent to the motor driving unit 104 in the form of a motor Pulse control signal, and the motor driving unit 104 generates 6 paths of PWM chopping signals with corresponding period sequences according to the received motor Pulse control signal based on a PWM (Pulse Width Modulation) principle, and changes and drives the voltage values at the two ends of the winding of the three-phase brushless dc motor by controlling the duty ratio of the 6 paths of PWM chopping signals, thereby changing the current in the winding and achieving the purpose of controlling the motor to rotate at a given speed and direction.

The working power supply of the three-phase brushless direct current motor is direct current, and the direct current is converted into three-phase alternating current through an inverter circuit and is output to a three-phase armature winding of the three-phase brushless direct current motor. The PWM control principle is that motor pulse trains with equal pulse widths are used as PWM waveforms, the frequency modulation purpose can be achieved by changing the period of the pulse train, and the voltage regulation purpose can be achieved by changing the width or duty ratio of the pulses. The rotation speed control of the direct current motor can be realized by a PWM technology, the period of a pulse sequence is changed according to the indicated speed variation, and then the duty ratio of the PWM is adjusted to linearly change the voltage at two ends of the motor, so that the rotation speed of the motor is controlled.

In the embodiment of the application, a three-phase brushless dc motor is powered by a dc power supply, the motor driving unit 104 includes an inverter circuit for converting dc power into three-wire ac power, the motor driving unit 104 generates 6 paths of PWM chopping signals according to the PWM control principle, and controls the on-time and off-time of 6 paths of inverter bridge switches of the inverter circuit through the driving units of the power switch tubes of each path of bridge circuit, so that the output end of the inverter circuit obtains a series of voltage pulses with equal amplitude, and the voltage pulses are used to replace sine wave voltage or required waveform voltage. Thus, the width of each pulse is modulated according to a certain rule according to the pulse sequence output by the main control unit 103, and the magnitude of the output voltage of the inverter circuit can be changed, and the output frequency can also be changed. Therefore, the direct-current power supply is converted into three-phase alternating current required by the three-phase armature winding of the stator during working, a rotating magnetic field is formed after the three-phase armature winding is electrified, the rotating magnetic field applies torque to the permanent magnet in the rotor, the rotor is pulled to rotate, and the lifter is driven.

Referring to fig. 2, a specific example of the control system provided in the embodiment of the present application is shown, and the working principle of the control system of the present application is described in detail with reference to the specific example. As shown in fig. 2, the motor drive unit 103 mainly includes: PWM control circuit, inverter circuit and commutation signal detection circuitry, wherein, inverter circuit includes the bridge circuit that 6 power switch tubes Q1-Q6 formed, and every power switch tube Q corresponds and is provided with drive unit, and commutation signal detection circuitry includes back electromotive force detection circuitry and converting circuit.

In the control system shown in fig. 2, the main functions of the respective units include:

1. operating unit 201

The operation unit 201 sends a motor control signal to the main control unit 203 according to the received mechanical operation action. The motor control signals include a motor rotation speed control signal and a motor rotation direction control signal, wherein the motor rotation speed control signal is an analog quantity signal output in response to a mechanical operation action, the operation unit 201 can convert a mechanical operation of an operator into a voltage signal, i.e., a motor rotation speed given signal Ui, the motor rotation direction control signal is two digital quantity signals indicating a motor rotation direction with a high level, for example, the motor rotation direction signal Dcw and Dccw, Dcw and Dccw are two digital signals indicating clockwise rotation and counterclockwise rotation, for example, Dcw indicates clockwise rotation when high level, and Dccw indicates counterclockwise rotation when high level. The two rotating directions of the motor respectively correspond to the ascending and descending working states of the lifter. For example, clockwise rotation corresponds to the elevator ascending, counterclockwise rotation corresponds to the elevator descending, and conversely, when counterclockwise rotation corresponds to the elevator descending, clockwise rotation corresponds to the elevator ascending.

2. Motor speed detection unit 202

The motor speed detection unit 202 detects a motor rotation signal through a magnetic angle encoder chip, the motor rotation signal comprises A, B two paths of orthogonal pulse signals and a zero position Z signal, and forward and reverse steering angle measurement can be conveniently performed according to A, B, Z three paths of signals.

3. Master control unit 203

The main control unit 203 calculates a target rotation speed ni of the motor according to the voltage signal Ui sent by the operation unit:

ni＝k1*Ui

k1 is a proportionality coefficient of the target rotation speed and the feedback analog voltage of the main control unit, so that the highest voltage corresponds to the highest rotation speed, the lowest voltage corresponds to the rotation speed, and k1 mainly depends on the ratio between the range of the feedback voltage of the main control unit and the rotation speed range preset by the motor.

The main control unit 203 receives A, B, Z three signals, detects a phase interval time ts when A, B signals are alternately changed into high level through the orthogonal coding interface, and calculates a motor feedback rotating speed nc:

nc＝k2(1/ts)

ts may be the time interval ts1 when the a signal leads the B signal, or the time interval ts2 when the B signal leads the a signal. k2 is inversely proportional to the encoder subdivision, the smaller the subdivision, the larger the value of k2, and the higher the corresponding rotational speed for the same time interval ts. ts1 can be seen in FIG. 7a, and ts2 can be seen in FIG. 7 b.

The main control unit 203 obtains a motor control rotation speed variation Δ n through PID calculation according to the motor target rotation speed ni and the motor feedback rotation speed nc, generates a control signal according to Δ n, and sends the control signal to the motor driving unit, and the PID calculates the rotation speed variation Δ n:

kp, Ki and kd are three main parameters controlled by PID respectively, wherein Kp is a proportional coefficient: expressing the influence of speed deviation on the control link regulating quantity, causing unstable oscillation of the system due to overlarge Kp value, and expressing Ki as an integral time constant: the method is used for eliminating the steady-state error of the system, the response speed of the response speed adjustment is high and low, kd represents a differential time constant, and the change trend of the speed error is reflected and used for eliminating the static error.

Ts is a lag or lead time parameter of the PID control system, and the absolute value of the lag or lead time parameter is in direct proportion to the ratio of the sampling period Ta of the feedback signal to the adjusting period Tc of the PID control.

For the control system, the adjustment period Tc of the PID control must be longer than the sampling period Ta of the speed feedback signal, so as to ensure that the feedback signal is received at least once in one adjustment period, and therefore: 0< Ts < 1.

In fact, the control system has inertia, and after the output of the motor control signal changes, the feedback value does not change immediately, and a period of time needs to be waited, so that the speed of integration needs to be matched with the inertia of the actual system.

When the motor is loaded and rises, the inertia is relatively small (the direction of the inertia of the motor is opposite to that of the load), the feedback of a system signal is delayed, the value of Ts is negative, the adjustment intensity of an integral link is enhanced, meanwhile, a differential time constant is increased, the adjustment intensity of a differential is enhanced, and the system carries out delay compensation control, and the corresponding PID formula is as follows.

On the contrary, when the motor is loaded and reduced, the inertia is relatively large (the direction of the motor is consistent with the direction of the load inertia), the system signal feedback is advanced, the value of Ts is positive, the adjustment intensity of an integral link is weakened, the differential time constant is reduced, the differential adjustment intensity is reduced, and the system carries out advanced compensation control, and the corresponding PID formula is as follows.

Wherein: kd1> kd 2.

Therefore, before calculating the rotation speed variation Δ n, the main control unit 203 determines the motor rotation direction of the three-phase dc brushless motor according to the motor rotation direction control signal, where the motor rotation direction corresponds to different working states of the elevator, for example, the motor rotates clockwise to drive the elevator to ascend, the motor rotates counterclockwise to drive the elevator to descend, and of course, the motor rotates counterclockwise to drive the elevator to ascend, and the motor rotates clockwise to drive the elevator to descend. When the rotating direction of the motor is in a working state of driving the elevator to ascend, Ts is set to be a negative value when the rotating speed variation is calculated, when the three-phase direct current brushless motor is determined to be in a working state of driving the elevator to descend, Ts is set to be a positive value when the rotating speed variation is calculated, and the value of kd is adjusted according to the motor rotating direction control signal, so that the value of kd for calculating the rotating speed variation when the elevator is driven to ascend is larger than the value of kd for calculating the rotating speed variation when the elevator descends.

The working condition that the lifter drags the load to rise and fall is different, the moment of inertia of the load is opposite to the moment of inertia of the motor rotor when the load rises, and the moment of inertia of the load is consistent with the moment of inertia of the motor rotor when the load falls. Because the rotary inertia of the motor of the outer rotor is large, different control schemes are needed when the belt load rises and falls. When the load rises, the auxiliary control of the brake unit is adopted during starting, the motor is accelerated first, the torque is gradually increased, the motor waits for reaching a certain torque, and then the brake is released, so that the load is ensured not to slide down due to inertia; in speed closed-loop control, an integral link is used for lag adjustment and compensation, and a differential link is used for increasing; when the load is reduced, the reverse torque is utilized for control during starting, the motor gives the maximum reverse torque after being rapidly started, and the brake is released at the same time, so that the motor can resist the load and rapidly slide downwards when the brake is opened; in the speed closed-loop control process, the integral link is adjusted and compensated in advance, and the differential link is reduced at the same time, so that the jitter caused by the rotational inertia of the rotor of the motor during the descending process is counteracted.

The main control unit 203 determines the pulse width of the motor pulse control signal according To the motor control rotation speed variation Δ no, further generates a motor pulse control signal To according To the motor rotation direction, and sends the motor pulse control signal To the motor driving unit.

The motor pulse control signal, as shown in fig. 4a, may be, for example, a pulse having a period of 20ms and a pulse width varying between 1.0 and 2.0 ms. In order to distinguish the rotation directions of the motor, different pulse width ranges can be set for clockwise rotation and anticlockwise rotation, and the pulse width ranges corresponding to the clockwise rotation direction and the anticlockwise rotation direction are different and do not have an intersection. And in the two pulse width ranges, the pulse width can be positively or negatively correlated with the rotation speed variation Δ no. For example, if a specific pulse width T0 is used as the elevator stop signal, then a pulse width greater than or equal to Tmin but less than T0 indicates clockwise rotation and a pulse width greater than T0 and less than or equal to Tmax indicates counterclockwise rotation, or vice versa, bounded by T0. Specific examples are as follows:

as shown in fig. 4b, if the pulse width T0 is equal to 1.5ms, the pulse width T1-T0-1.5 ms when the motor stops the elevator and keeps stationary;

as shown in fig. 4c, when the rotation direction of the motor is the rotation direction for driving the elevator to ascend, Dcw is 1 (high level), and the pulse width T1 varies between 1.0 and 1.5ms, the pulse width and the rotation speed are inversely related, the smaller the pulse width is, the larger the rotation speed is, and the pulse width of 1.0ms corresponds to the highest rotation speed of the motor when the motor rotates in the rotation direction; as shown in fig. 4d, when the rotation direction of the motor is the rotation direction for driving the elevator to descend, Dccw is 1 (high level), and the pulse width T1 varies between 1.5 and 2.0ms, the pulse width and the rotation speed are positively correlated, the larger the pulse width, the larger the rotation speed, and the 2.0ms pulse width corresponds to the highest rotation speed of the motor when the motor rotates in the rotation direction. The rotation direction of the motor driving the elevator to ascend can be a clockwise rotation direction, the rotation direction of the motor driving the elevator to descend is an anticlockwise rotation direction, otherwise, the rotation direction of the motor driving the elevator to ascend is an anticlockwise rotation direction, and the rotation direction of the motor driving the elevator to ascend is a clockwise rotation direction. The highest rotation speeds in the two different rotation directions may be the same or different.

Therefore, according To the rotation speed setting signal Δ no, based on T0, the pulse width variation Δ To is K3 × Δ no, where K3 represents the ratio of the pulse width range of the motor pulse control signal To the corresponding rotation speed range, i.e., 0.5ms (1.5 ms-2.0 ms or 1.5 ms-1.0 ms)/the maximum rotation speed of the motor.

When Dcw is 1 (high), the pulse width To ═ T0- Δ To ═ 1.5-K3 ═ Δ no) ms;

when Dccw is 1 (high), the pulse width To is T0+ Δ To (1.5+ K3 Δ no) ms.

As can be seen from the above example, the pulse width ranges indicating clockwise and counterclockwise rotation of the motor are two different pulse ranges, and the present application distinguishes between the first range and the second range, and the first range may be two completely independent ranges, or may be bounded by a specific pulse width T0, one of which may be Tmin or greater than Tmin and less than T0, the other may be greater than T0 and less than Tmax, and Ta is greater than zero. The widths of the first range and the second range may be the same or different.

If bounded by T0, a pulse train of width T0 may be used to indicate that the motor is not running. For example, when determining the pulse width according To the rotation direction of the motor and the amount of change in the rotation speed, and determining the pulse width range in different rotation directions, when the rotation direction of the motor is clockwise rotation, the pulse width To of the pulse control signal is T0- Δ To, Δ To is Q1 × Δ no, and Q1 represents the ratio of the pulse width range of the motor pulse control signal To the rotation speed range of the clockwise rotation of the motor; when the motor rotates counterclockwise, the pulse width To of the pulse control signal is T0+ Δ To, and Δ To is Q2 Δ no, and Q2 represents the ratio of the pulse width range of the motor pulse control signal To the rotation speed range of the motor rotating counterclockwise. When the operator needs to stop the operation, the operation unit may transmit a Ui signal indicating that the analog voltage value is 0. When receiving the Ui signal with the voltage value of 0, the main control unit generates a pulse control signal with the pulse width of T0.

When the main control unit 203 detects that Ui transmitted from the operation unit 201 is greater than 0V and detects that any 1 of the motor rotation direction signal Dcw or Dccw signal is at low level, the motor rotation direction is determined according To the level signal of Dcw or Dccw, Δ no and the pulse width To are further determined, and then a motor pulse control signal is transmitted To the motor driving unit according To the motor rotation direction and the pulse width To. And determining a control signal of the brake unit according to the ascending or descending working condition.

As shown above, the control signal of the brake driving unit 205 needs to consider the working condition of the lifter when dragging the load to rise and fall, if the working condition is rise, the moment of inertia of the load is opposite to the moment of inertia of the motor rotor, and when the working condition is fall, the moment of inertia of the load is consistent with the moment of inertia of the motor rotor. When the elevator is lifted, the driving unit 205 starts the auxiliary control of the braking unit to keep the braking unit in a pull-in state, the three-phase brushless DC motor is braked to keep the position of the elevator, then the three-phase brushless DC motor is controlled to accelerate, namely the working voltage of the three-phase brushless DC motor is gradually increased to obtain a certain torque, the braking unit is released after the voltage value reaches a set value, namely the torque reaches a certain torque to overcome the rotational inertia of the load, so as to prevent the elevator from sliding down, in the specific control process, because the working voltage of the three-phase brushless DC motor is positively correlated with the rotational speed variation, when the rotational speed variation can be used as a control parameter, when the rotational speed variation reaches the set value, a control signal for releasing the braking unit is sent to the braking driving unit 205, and the braking driving unit 205 responds to the control signal for releasing the braking unit, and controlling the brake unit to release the brake. When the load of the elevator is reduced, the reverse torque control is utilized during starting, the three-phase brushless direct current motor is rapidly started, the working voltage is increased to the maximum value, the maximum reverse torque is obtained, meanwhile, the brake unit is released, namely, a control signal for releasing the brake unit is sent to the brake driving unit 205, the brake driving unit 205 responds to the control signal for releasing the brake unit, the brake unit is controlled to release the brake, and the elevator is enabled to resist the load to rapidly slide down when the brake is opened.

5. The PWM control circuit in the motor drive unit 204 controls the operating voltage of the three-phase brushless dc motor according to the motor pulse control signal.

As shown in fig. 5a, three-phase back electromotive forces Ea, Eb, Ec corresponding to U, V, W three-phase armature windings of the three-phase brushless dc motor are converted into digital quantity phaseA, phaseB, phaseC back electromotive force signals by the back electromotive force detection circuit, and as shown in fig. 5b, the phaseA, phaseB, phaseC obtain 6-path phase-change signals Q1-Q6 through the conversion circuit and input to the PWM control circuit. The specific calculation method is well known to those skilled in the art and will not be described herein.

When the PWM control circuit in the motor driving unit 204 receives the motor pulse control signal with pulse width To, it further needs To convert the motor pulse control signal into a duty ratio D of K4 (To-1.5ms) in combination with the 6 commutation signals Q1-Q6 detected by the commutation signal detection circuit, where K4 represents the ratio of the adjustment range of the PWM duty ratio To the pulse width of the motor pulse control signal, and the value is (highest speed duty ratio-lowest speed duty ratio)/0.5 ms (i.e. 1.5 ms-2.0 ms or 1.5 ms-1.0 ms), and the 6 PWM chopping signals PWM1-PWM6 with frequency f, and according To the sequence as shown in fig. 5c, the driving units of the respective power switching tubes control the on and off of the Q1-Q6 power switching tubes respectively, so that the dc power source is sequentially applied To two ends of the two-phase winding in the three-phase winding within one period of electrical angle, generating an electric current that drives the motor to rotate. Voltage value applied to each phase winding of motor

Wherein Ub is the dc supply voltage of the control system. Three-phase alternating current output by each output end of the inverter circuit is loaded to each phase armature winding, and each phase of the armature winding generates alternating current, and the alternating current forms a rotating magnetic field to drive the three-phase brushless direct current motor to operate.

6. When the operation unit 201 receives the stopped operation signal, a voltage rotating speed given signal with Ui of 0V is sent to the main control unit 203, and when the main control unit 203 receives the rotating speed given signal with Ui of the operation unit 201 of 0V, a motor pulse control signal with 1.5ms pulse width is sent to the motor driving unit 204 to stop the action of the three-phase brushless direct current motor, and meanwhile, a stop signal is sent to the brake unit driving unit 205 to enable the brake unit to be powered off and closed to brake the three-phase brushless direct current motor.

7. A motor temperature detection unit 202.

A specific example of a motor temperature detection unit is shown in figure 8, and comprises a full-bridge sampling circuit and an amplifying circuit, wherein the full-bridge sampling circuit is composed of a temperature sensor and three resistors, the temperature sensor can adopt a three-wire compensation temperature sensor, the three-phase complementary sensor comprises a temperature sensing resistor and three pins, the temperature sensing resistor is connected between the two pins, the resistance values of transmission line resistors of the two pins are equal, and the third pin in the three pins is grounded. The three-wire compensated temperature sensor is, for example, the PT100 shown in fig. 8, and the other three resistors include R92, R93 and RW4, where RW4 is an adjustable resistor. The temperature sensor PT100 is installed on the stator, and in the operation process of the three-phase brushless direct current motor, the resistance value R of the temperature sensor PT100 is changed along with the change of the temperature, the voltage output to R94 and R95 by the full-bridge sampling circuit is changed, and the voltage is output by the UT end and is transmitted to the main control unit after being amplified by the amplifying circuit.

The PT100 adopts a three-wire compensation temperature sensor, in order to avoid sampling errors caused by the wire length of the sensor, the transmission line resistance values of two pins are equal, namely the transmission line resistance values of the pin 1 and the pin 2 are equal, namely the transmission line resistance values between the pin 1 and the pin 2 and the connection point of the full bridge circuit are equal, if the two pins are the same lead, the wire lengths from the pin 1 and the pin 2 to the connection point of the bridge arm are equal, and the pin 3 is grounded. It should be noted that, the transmission line resistors are equal in resistance, that is, equal or approximately equal within a certain error range.

The relationship between PT100 resistance and motor temperature can be expressed as: r is 0.3851T_M+100, where 0.3851 is a scaling factor, T_MIs the current motor temperature.

The output voltage U of the two bridge arms is obtained through a sampling circuit_R＝K_T1*(R-100)＝0.3851K_T1*T_MIn which K is_T1Is a scaling factor.

Because the signal obtained by the sampling circuit is small, the signal needs to be amplified and then input into the main control unit. The amplifying circuit adopts an AD623 single-power amplifier, and the amplification factor can be changed by adjusting a resistor R96. The amplification factor G of the circuit shown in fig. 8 is 100K/

R96+

1, 100K/2K +1, 51.

Is converted into U by an amplifying circuit_T＝K_T2*U_R＝0.3851K_T1*G*T_MRear, U_TTransmitted to the master control unit, where K_T2Is a scaling factor. The main control unit is according to U_TConverting to obtain the current temperatureT_MWhen T is_MAnd when the maximum motor working temperature is higher than the maximum motor working temperature upper limit Tmax, the main control unit immediately sends a motor pulse control signal with the pulse width of 1.5ms to the motor driving unit to stop the motor action or further start the auxiliary heat dissipation device to strengthen heat dissipation.

Because AD623 is a single power amplifier, resistors R100, R101 and U19C are adopted to generate a REF pin of a 1.65V input AD623 of a reference power supply, the central value of an output UT of the amplifier is raised to 1.65V, and the UT is enabled to change within a range of 0-3.3V by taking 1.65V as a center.

8. When the main control unit 203 detects that the feedback rotating speed nc exceeds the maximum rotating speed allowed by the motor, the three-phase brushless direct current motor is immediately stopped to act, and meanwhile, a stop signal is sent to the brake unit driving unit, so that the brake unit is powered off and is attracted, and the three-phase brushless direct current motor is braked.

9. When the main control unit 203 detects that the rotation direction of the feedback rotation speed nc is not consistent with the rotation direction of the motor given by the operation unit, the three-phase brushless direct current motor is immediately stopped to act, and meanwhile, a stop signal is sent to the brake unit driving unit, so that the brake unit is powered off and is attracted, and the three-phase brushless direct current motor is braked.

In summary, the following steps: and (1) the steps 1-6 are the processes of starting, running and stopping the motor, simultaneously carrying out system monitoring in 7, 8 and 9 in real time, and immediately stopping the action of the three-phase brushless direct current motor once overtemperature, overspeed and wrong rotation direction are detected so as to brake the three-phase brushless direct current motor.

Referring to fig. 3: the main power range DC28-42V of the control system is suitable for use, for example, DC37V is adopted for power supply, and the working power of each unit in the control system is converted from the main power. One path of the main power supply is directly supplied to the motor driving unit, and the other path of the main power supply converts a direct current to direct current circuit (DC/DC) into DC24 to be supplied to the brake driving unit of the brake unit; the DC24V is divided into one path and converted into DC12V to be supplied to a control circuit of a brake driving unit, and the other path is converted into DC5V to be supplied to an operation unit and a motor speed detection unit; the DC5V is converted into DC3.3V to be supplied to the main control unit and the motor temperature detection unit, respectively.

The values in the above examples are only exemplary, for example, the main control unit continuously sends a pulse signal with a period T of 20ms and a pulse width of 1.0-2.0ms to the motor driving unit to control the operation of the motor. When the pulse width is 1.5ms, the motor is in a stop state; when the pulse width is changed between 1.0ms and 1.5ms, the motor can rotate clockwise, the smaller the pulse width is, the larger the rotating speed is, and the pulse width of 1.0ms corresponds to the highest rotating speed of the clockwise rotation of the motor; when the pulse width is changed between 1.5ms and 12.0ms, the motor can rotate anticlockwise, the larger the pulse width is, the larger the rotating speed is, and the 2.0ms pulse width corresponds to the highest rotating speed of the motor in anticlockwise rotation. The motor can drive the elevator to ascend when rotating clockwise, and conversely, the motor can drive the elevator to descend when rotating anticlockwise. Or the motor can drive the elevator to ascend when rotating anticlockwise, and conversely, the motor can drive the elevator to descend when rotating clockwise. The example is not intended to limit the scope of the present application, and those skilled in the art can adjust various control parameters according to practical applications.

Referring to fig. 6, as an assembly schematic diagram of the magnetic angle encoder, a detection magnetic pole is coaxially installed at the tail end of the three-phase brushless DC motor, the detection magnetic pole rotates along with the three-phase brushless DC motor, and a magnetic encoding chip circuit is placed right below the detection magnetic pole as shown in fig. 6, and the magnetic encoding chip can be supplied with power by AM256 and DC 5V. When the three-phase brushless direct current motor is installed, the interval between the detection magnetic pole and the magnetic coding chip is about 1-2ms, when the three-phase brushless direct current motor rotates, the detection magnetic pole generates a magnetic field changing in rotation, and the magnetic coding chip is triggered to generate DC5V square wave orthogonal pulse A-phase and B-phase signals. The amplitudes of the phase A and the phase B are the same as 5V, and the phase difference is 90 degrees; when the phase A leads the phase B, the three-phase brushless direct current motor rotates clockwise, as shown in FIG. 7 a; when the phase B leads the phase a, it represents that the three-phase brushless dc motor rotates counterclockwise, as shown in fig. 7B. The main control unit receives the signals of the A phase and the B phase and counts the phase difference ts1 or ts2 of the signals of the A phase and the B phase to calculate the rotating speed of the three-phase brushless direct current motor.

In a specific example, the MCU control chip of the main control unit may use the DSPIC33FJ128MC706A, DC3.3V to supply power, and perform signal transmission with other DC5V control units through the level shift chip 74ALVC164245 DL. The method comprises the steps of respectively acquiring a three-phase brushless direct current motor rotating speed analog quantity given signal and a three-phase brushless direct current motor temperature feedback signal of an operation unit through two AD peripheral interfaces of a chip. The speed feedback A, B, Z phase signals of the three-phase brushless direct current motor are collected through the orthogonal encoder interface, the rotation direction signals of the two three-phase brushless direct current motors of the operation unit are received through the common I/O port, and the control signals of the brake unit are output. And outputting motor control pulses of the three-phase brushless direct current motor through the PWM peripheral channel. The main control unit outputs control pulses suitable for pulse width through calculation according to the given rotating speed and the detected rotating speed, and a closed-loop control system for the operation of the three-phase brushless direct current motor is formed. The main control unit simultaneously monitors whether the rotation of the three-phase brushless direct current motor exceeds the highest rotation speed of the three-phase brushless direct current motor and whether the rotation direction of the three-phase brushless direct current motor is correct or not in real time according to the feedback rotation speed, if overspeed or direction error is detected, and if the rotation direction of the three-phase brushless direct current motor is not consistent with the set rotation direction, the three-phase brushless direct current motor is immediately stopped, so that serious consequences are avoided.

In summary, the present application provides a control system for a three-phase brushless dc motor driving a lifter, and provides a control method based on a PID algorithm, the control method mainly comprising:

obtaining a target rotating speed and a motor feedback rotating speed of a three-phase brushless direct current motor for driving the elevator;

and determining the rotation speed variation delta no by adopting a PID (proportion integration differentiation) control method, and when the motor rotation direction control signal indicates that the three-phase direct-current brushless motor is in a working state of driving the elevator to ascend:

when the motor rotation direction control signal indicates that the three-phase direct current brushless motor is in a working state of driving the elevator to descend:

Based on the foregoing control method, an embodiment of the present application further provides a control device of the foregoing control system, as shown in fig. 9, including:

an obtaining unit 901 configured to obtain a motor target rotation speed and a motor feedback rotation speed of a three-phase brushless dc motor that drives the elevator;

the determining unit 902 is configured to determine a rotation speed variation Δ no by using a PID control method, and when the motor rotation direction control signal indicates that the three-phase dc brushless motor rotates clockwise to drive the elevator to ascend:

when the motor rotation direction control signal indicates that the three-phase direct current brushless motor rotates anticlockwise to drive the elevator to descend:

a sending unit 903, configured to generate a pulse control signal for controlling the three-phase brushless dc motor according to the motor rotation direction and the rotation speed variation, and send the pulse control signal to a motor driving unit of the three-phase brushless dc motor.

The specific principles and implementations related to each step in the foregoing method and each unit in the control device are as described above, and are not described herein again.

In an exemplary embodiment, a computer-readable storage medium, such as a memory including a computer program, executable by a processor, is also provided to perform the artificial intelligence based video generation method of the above embodiments. For example, the computer-readable storage medium may be a Read-Only Memory (ROM), a Random Access Memory (RAM), a Compact Disc Read-Only Memory (CD-ROM), a magnetic tape, a floppy disk, an optical data storage device, and the like.

In an exemplary embodiment, a computer program product or a computer program is also provided, which includes a computer program code stored in a computer readable storage medium, and a processor of a computer device, such as the aforementioned main control chip, can read the computer program code from the computer readable storage medium and execute the computer program code to implement the control method provided in the above-described embodiment.

It will be understood by those skilled in the art that all or part of the steps of implementing the above embodiments may be implemented by hardware, or by a computer program and hardware related to the computer program, and the computer program may be stored in a computer readable storage medium, and the above mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.

The above description is only exemplary of the present application and should not be taken as limiting, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A control system for a three-phase brushless dc motor for driving a lifter, the three-phase brushless dc motor comprising a stator and a rotor, the stator being disposed within the rotor, a three-phase armature winding being disposed in the stator, the control system comprising: the device comprises an operation unit, a main control unit, a motor driving unit and a motor rotating speed detection unit; wherein:

2. The control system of claim 1, wherein the motor rotation speed detecting unit includes a magnetic angle encoder including a magnetic encoder chip and a detection magnetic pole coaxially fitted with the rotor and rotating in synchronization with the rotor, the magnetic encoder chip sensing a rotation change of the detection magnetic pole to generate the rotation speed detection signal.

3. The control system of claim 1, wherein the motor drive unit comprises: pulse width modulation PWM control circuit, inverter circuit, back electromotive force detection circuitry and converting circuit, wherein:

4. The control system of claim 1, wherein: the motor rotating speed control signal comprises an analog quantity voltage signal output according to the operation mechanical action; the motor rotation direction control signal comprises two paths of digital quantity signals, wherein one path of digital quantity signal is used for indicating that the motor rotation direction is clockwise rotation, and the other path of digital quantity signal is used for indicating that the motor rotation direction is anticlockwise rotation.

5. The control system according to any one of claims 1 to 4, wherein the generating of the pulse control signal for controlling the three-phase brushless DC motor according to the motor rotation direction and the rotation speed variation specifically includes:

6. The control system according to claim 5, wherein the main control unit determines the speed variation Δ no by using a PID control method, and when the motor rotation direction control signal indicates an operation state in which the three-phase dc brushless motor drives the elevator to ascend:

when the motor rotation direction control signal indicates the three-phase brushless DC motor to drive the elevator to descend:

7. The control system of claim 6, wherein the three-phase brushless DC motor drives the elevator to ascend and descend in different directions of rotation of the motor, wherein in one direction of rotation, the pulse width range of the pulse control signal is a first range, in the other direction of rotation, the pulse width range of the pulse control signal is a second range, and the first range and the second range are different and do not overlap.

8. The control system according to claim 7, wherein the operation unit is further configured to transmit a motor control signal for instructing the motor to stop running, in accordance with an operation of stopping the elevator;

9. The control system of claim 8, wherein determining a pulse width based on the direction of rotation of the motor and the amount of change in the speed of rotation comprises:

10. The control system of claim 6, further comprising: the brake driving unit responds to a brake control signal of the main control unit, controls the brake unit to act, and brakes or releases the brake of the three-phase brushless direct current motor; wherein:

11. The control system according to any one of claims 1 to 4, further comprising a temperature detection unit for detecting a temperature of the dc brushless motor during operation and feeding back a temperature detection signal to the main control unit, wherein the main control unit controls the temperature of the three-phase brushless dc motor according to the fed back temperature detection signal, wherein the temperature detection unit comprises a full-bridge sampling circuit and an amplifying circuit, and the temperature detection signal sampled by the sampling circuit is amplified by the amplifying circuit and then transmitted to the main control unit, wherein:

12. A control method for the control system according to claims 1 to 4, characterized by comprising the steps of:

13. The control method according to claim 12, wherein a pulse width range of the pulse control signal is a first range when the motor rotation direction is clockwise rotation, and a pulse width range of the pulse control signal is a second range when the motor rotation direction is counterclockwise rotation, the first range and the second range being different and not overlapping.

14. The control method according to claim 13, further comprising:

when the motor control signal for indicating the motor to stop running is received, generating a pulse control signal with the pulse width of set width T0, wherein the pulse control signal with the pulse width of T0 is used for braking control of the three-phase brushless direct-current motor;

15. The control method according to claim 14, wherein determining a pulse width according to the rotation direction of the motor and the rotation speed variation includes:

when the motor rotates clockwise, the pulse width To of the pulse control signal is T0- Δ To, and Δ To is Q1 Δ no, and Q1 represents the ratio of the pulse width range of the motor pulse control signal To the rotating speed range of the motor rotating clockwise;

when the motor rotates counterclockwise, the pulse width To of the pulse control signal is T0+ Δ To, and Δ To is Q2 Δ no, and Q2 represents the ratio of the pulse width range of the motor pulse control signal To the rotating speed range of the motor rotating counterclockwise.

16. A control device for use in the control system according to claims 1 to 4, comprising:

17. A computer-readable storage medium, having at least one computer program stored therein, the computer program being loaded and executed by a processor to perform operations performed by the method of any one of claims 12 to 15.