CN217904290U

CN217904290U - Motor commutation control circuit

Info

Publication number: CN217904290U
Application number: CN202221349655.6U
Authority: CN
Inventors: 张金
Original assignee: Jiangsu Dongcheng Tools Technology Co Ltd
Current assignee: Jiangsu Dongcheng Tools Technology Co Ltd
Priority date: 2022-05-31
Filing date: 2022-05-31
Publication date: 2022-11-25
Anticipated expiration: 2032-05-31

Abstract

The utility model discloses a motor commutation control circuit, include: the power just, the negative terminal, just, the negative terminal passes through drive circuit and connects in the motor, drive circuit passes through PWM signal production circuit and connects in the controller, the controller passes through back electromotive force detection circuitry and connects in order to receive motor speed in the motor, back electromotive force detection circuitry passes through motor commutation calculation module and connects in the controller, the inside storage of controller has the corresponding relation of motor speed and PWM signal frequency, the controller receives motor speed and sends corresponding PWM signal and give drive circuit with driving motor, commutation calculation module is based on PWM signal and motor speed output commutation signal and gives the controller and carries out the commutation. The utility model discloses change PWM signal frequency and commutation signal according to motor speed to realize high accuracy, high efficiency commutation.

Description

Motor commutation control circuit

[ technical field ] A

The utility model relates to a motor control's technical field, in particular to control circuit of motor commutation.

[ background ] A method for producing a semiconductor device

The existing brushless motor carries out phase change by detecting the waveform of counter electromotive force of a suspended phase winding and delaying a preset time interval after acquiring a zero crossing point so as to realize the driving of the motor, a PWM signal is sent to a driving circuit by a controller, and the counter electromotive force voltage is acquired in the ON stage of the PWM signal and whether the zero crossing point is reached is judged, but the phase change time of the motor is usually changed by the rotating speed of the motor.

Therefore, it is necessary to design a motor commutation control circuit with high efficiency and high precision to solve the above problems.

[ Utility model ] A method for manufacturing a semiconductor device

Not enough to prior art, the utility model aims to provide an efficient and high motor commutation control circuit of precision.

The utility model provides a prior art problem can adopt following technical scheme: a motor commutation control circuit comprising: the power just, negative terminal, drive circuit, PWM signal production circuit, controller and back electromotive force detection circuitry, just, the negative terminal passes through drive circuit and connects in the motor, drive circuit passes through PWM signal production circuit and connects in the controller, the controller pass through back electromotive force detection circuitry connect in the motor is in order to receive motor speed, motor commutation control circuit still includes commutation calculation module, back electromotive force detection circuitry pass through commutation calculation module connect in the controller, the inside storage of controller has the corresponding relation of motor speed and PWM signal frequency, the controller receives motor speed and sends corresponding PWM signal and gives drive circuit is in order to drive the motor, commutation calculation module exports commutation signal based on PWM signal and motor speed and gives the controller carries out the commutation.

The further improvement scheme is as follows: the motor commutation control circuit further comprises a rotating speed detection module connected between the back electromotive force detection circuit and the controller, and the rotating speed detection module calculates the rotating speed of the motor based on the back electromotive force detection circuit and sends the rotating speed to the controller.

The further improvement scheme is as follows: the PWM signal frequency stored in the controller is in a positive relation with the rotating speed.

The further improvement scheme is as follows: the commutation calculation module is connected with the rotating speed detection module and the controller, stores the relationship between the rotating speed of the motor and a commutation set value, and selects the corresponding commutation set value relationship according to the rotating speed so as to output a commutation signal to the controller for commutation.

The further improvement scheme is as follows: the motor comprises a three-phase winding, the controller controls the conduction of the two-phase winding, the counter electromotive force detection circuit detects the counter electromotive force of a suspension phase, the counter electromotive force comprises a rising edge and a falling edge, the PWM signal comprises an ON stage and an OFF stage, the duration of one ON stage and one OFF stage is the period of the PWM signal, and the reciprocal of the period is the frequency of the PWM signal.

The further improvement scheme is as follows: the commutation calculation module samples a back electromotive force at an ON stage of the PWM signal.

The further improvement scheme is as follows: the commutation set value is a percentage value of the power voltage, and the percentage value is in a positive relation with the rotating speed of the motor.

The further improvement scheme is as follows: the motor is a brushless motor.

Compared with the prior art, the utility model discloses following beneficial effect has: the controller stores the corresponding relation between the motor rotating speed and the PWM signal frequency, receives the motor rotating speed and sends a corresponding PWM signal to the driving circuit to drive the motor, the commutation calculation module outputs a commutation signal to the controller based on the PWM signal and the motor rotating speed to carry out commutation, the PWM signal frequency and the commutation signal are changed according to the rotating speed to realize high-precision commutation, and the PWM signal frequency and the commutation signal are changed according to the rotating speed to realize high-precision and high-efficiency commutation.

[ description of the drawings ]

The following detailed description of the embodiments of the present invention is provided with reference to the accompanying drawings:

fig. 1 is a circuit diagram of a motor commutation control circuit of the present invention;

FIG. 2 is the waveform of the back electromotive force when the rotation speed of the motor of the present invention is 1000 rpm;

fig. 3 is the back electromotive force waveform when the rotation speed of the motor of the present invention is 10000 rpm.

The meaning of the reference symbols in the figures:

1. drive circuit 2, motor 3, PWM signal generating circuit 4, controller 5, counter electromotive force detection circuit 6, rotational speed detection module 7, commutation calculation module

[ detailed description ] embodiments

The present invention will be described in further detail with reference to the accompanying drawings and embodiments.

Please refer to fig. 1, for the utility model relates to a motor commutation control circuit, motor control circuit includes that the power is just, negative terminal, just, negative terminal passes through drive circuit 1 and connects in motor 2, drive circuit 1 passes through PWM signal generation circuit 3 and connects in controller 4, controller 4 through back electromotive force detection circuit 5 connect in motor 2 is in order to receive motor speed, back electromotive force detection circuit 5 with be equipped with rotational speed detection module 6 and commutation calculation module 7 between controller 4, rotational speed detection module 6 connect in back electromotive force detection circuit 5 is used for calculating motor speed, the inside storage of controller 4 has the corresponding relation of motor speed and PWM signal frequency, controller 4 receives motor speed and sends corresponding PWM signal for drive circuit 1 is in order to drive motor 2, commutation calculation module 7 connects in rotational speed detection module 6 and controller 4 to output commutation signal for based on PWM signal and motor speed controller 4 and carry out the commutation.

The motor 2 is a brushless motor, and in the present embodiment, taking a star connection of three-phase windings as an example, the drive circuit 1 includes a first arm, a second arm, and a third arm, each arm is connected between positive and negative terminals of a power supply, and the first arm is composed of a first switching tube Q1 (also referred to as an upper switch) and a fourth switching tube Q4 (also referred to as a lower switch) connected in series; the second bridge arm consists of a second switching tube Q2 (also called an upper switch) and a fifth switching tube Q5 (also called a lower switch) which are connected in series; the third bridge arm is composed of a third switching tube Q3 (also called an upper switch) and a sixth switching tube Q6 (also called a lower switch) which are connected in series, three-phase windings of the motor 2 are respectively connected to the middle point of each bridge arm, the controller 4 sends a PWM signal to the PWM signal generating circuit 3, the PWM signal generating circuit 3 controls the upper switching tube of one bridge arm of the driving circuit 1 and the lower switching tubes of any other bridge arm to be conducted in pairs, the upper and lower switching tubes of the same bridge arm cannot be conducted simultaneously to control the conduction of the two-phase windings at each time, and therefore, the driving circuit 1 can respectively control the conduction of the switching tubes in the following six states: Q1Q5 switches on, Q1Q6 switches on, Q2Q4 switches on, Q2Q6 switches on, Q3Q4 switches on, Q3Q5 switches on, realizes the commutation of motor 2 through the switching of six kinds of states, makes the electric current flow through every coil in order, and the magnetic field that the electric current flow through the coil produced interacts with the magnet of rotor, and the magnetic pole of permanent magnet rotor changes thereby takes place to rotate. The counter electromotive force detection circuit 5 detects the counter electromotive force of a suspended phase winding, the rotating speed detection module 6 calculates the rotating speed of the motor based ON the counter electromotive force detection circuit 5 and sends the rotating speed to the controller 4, the PWM signals comprise ON stages and OFF stages, the duration of one of the ON stages and the duration of one of the OFF stages are the period of the PWM signals, the reciprocal of the period is the frequency, and the controller 4 changes the frequency of the PWM signals through the change of the rotating speed.

The controller 4 receives the rotating speed of the motor and sends a corresponding PWM signal to the PWM signal generating circuit 3, and the PWM signal generating circuit 3 sends the changed PWM signal to the driving circuit so as to change the rotating speed of the motor 2. The PWM signal frequency, which is in a positive relationship with the rotational speed, increases with increasing rotational speed received by the controller 4. The commutation calculation module 7 outputs commutation signals to the controller 4 based ON PWM signals and motor rotation speeds for commutation, the commutation calculation module 7 samples at the ON stage of the PWM signals, stores the relationship between the motor rotation speeds and commutation set values, selects the corresponding commutation set value relationship according to the motor rotation speeds, and outputs commutation signals to the controller 4 for commutation, the commutation set value is a percentage value of power voltage, the percentage value is in a positive relationship with the rotation speeds, and the percentage value increases with the increase of the rotation speeds.

As shown in fig. 2, the waveform of the back electromotive force is a waveform of the back electromotive force when the motor rotation speed is 1000rpm, the back electromotive force includes a rising edge and a falling edge, the rising edge is a commutation time, the controller 4 stores the motor rotation speed of the three-phase winding and the commutation time corresponding to the rotation speed, and further stores a relationship between the rotation speed and a PWM signal frequency, the rotation speed and the corresponding commutation time are in a reverse relationship, that is, the commutation time decreases with the increase of the rotation speed, in this embodiment, at least 3 counter electromotive forces are collected, one PWM signal frequency corresponds to a plurality of rotation speeds, that is, one PWM signal frequency corresponds to one rotation speed interval, the rotation speed interval is 1000rpm, but in other embodiments, the rotation speed interval may be set to other values. Taking a rotating permanent magnet rotor as an example of 2 pairs, if the rotating speed is 1000rpm, the corresponding commutation time is 5ms, the corresponding PWM signal frequency is 5K, that is, the period of the PWM signal is 0.2ms, and a peak is generated during commutation, so that the demagnetization time needs to be removed and then the detection is performed, in the present embodiment, the demagnetization time is half of the commutation time, that is, the acquisition is started at time a, the number of PWM signals is 12 (a part of the PWM signal is omitted in the figure) within 2.5ms, and the corresponding commutation set value is 40% of the power voltage, that is, the number of samples taken by the commutation calculation module 7 at the ON stage of the PWM signal is 12, and when the detected back electromotive force is 40% of the power voltage U, the commutation calculation module 7 outputs the commutation signal to the controller 4 and performs commutation.

As shown in fig. 3, the waveform of the back electromotive force when the rotation speed of the motor is 10000rpm, the rotation speed is increased, the corresponding commutation time is reduced to 0.5ms, if the frequency of the PWM signal is not changed, only 1 PWM signal can be output in the commutation time, according to the relationship between the rotation speed and the frequency of the PWM signal stored in the controller 4, the frequency of the PWM signal is 20K, that is, the period of the PWM signal is 0.05ms, the collection is started at time b after the demagnetization time is removed, and the number of the PWM signals is 5 (a part of the PWM signals are omitted in the drawing) in 0.25ms, so as to ensure the number of the collected back electromotive forces. And the corresponding commutation setting value is 70% of the power supply voltage, and when detecting that the back electromotive force is 70% of the power supply voltage, the commutation calculation module 7 outputs a commutation signal to the controller 4 and carries out commutation. The rotating speed is changed, and the PWM signal frequency corresponding to the rotating speed is changed, so that enough sampling times are ensured in the phase change time, the counter electromotive force is accurately acquired, and the accurate phase change is ensured.

The utility model discloses motor commutation control circuit has the corresponding relation of motor speed and PWM signal frequency through the inside storage of controller, and the controller is received motor speed and is sent the PWM signal that corresponds and give drive circuit with driving motor, and commutation calculation module is based on PWM signal and motor speed output commutation signal and gives the controller and carries out the commutation, changes PWM signal frequency and commutation signal according to the rotational speed in order to realize the high accuracy commutation.

The present invention is not limited to the above-described embodiments. It will be readily appreciated by those skilled in the art that there are numerous other alternatives to the motor commutation control circuit without departing from the spirit and scope of the invention. The protection scope of the present invention is subject to the content of the claims.

Claims

1. A motor commutation control circuit comprising: the power supply comprises a power supply positive terminal, a power supply negative terminal, a driving circuit, a PWM signal generating circuit, a controller and a back electromotive force detection circuit, wherein the positive terminal and the negative terminal are connected to a motor through the driving circuit, the driving circuit is connected to the controller through the PWM signal generating circuit, and the controller is connected to the motor through the back electromotive force detection circuit so as to receive the rotating speed of the motor; the method is characterized in that: the motor commutation control circuit further comprises a commutation calculation module, the counter electromotive force detection circuit is connected with the controller through the commutation calculation module, the controller stores the corresponding relation between the motor speed and the PWM signal frequency, the controller receives the motor speed and sends a corresponding PWM signal to the driving circuit to drive the motor, and the commutation calculation module outputs a commutation signal to the controller to carry out commutation based on the PWM signal and the motor speed.

2. The motor commutation control circuit of claim 1, wherein: the motor commutation control circuit further comprises a rotating speed detection module connected between the back electromotive force detection circuit and the controller, and the rotating speed detection module calculates the rotating speed of the motor based on the back electromotive force detection circuit and sends the rotating speed to the controller.

3. The motor commutation control circuit of claim 1, wherein: the PWM signal frequency stored in the controller is in a positive relation with the rotating speed.

4. The motor commutation control circuit of claim 2, wherein: the commutation calculation module is connected with the rotating speed detection module and the controller, stores the relationship between the rotating speed of the motor and a commutation set value, and selects the corresponding commutation set value relationship according to the rotating speed so as to output a commutation signal to the controller for commutation.

5. The motor commutation control circuit of claim 4, wherein: the motor comprises a three-phase winding, the controller controls the conduction of the two-phase winding, the counter electromotive force detection circuit detects the counter electromotive force of a suspension phase, the counter electromotive force comprises a rising edge and a falling edge, the PWM signal comprises an ON stage and an OFF stage, the duration of one ON stage and one OFF stage is the period of the PWM signal, and the reciprocal of the period is the frequency of the PWM signal.

6. The motor commutation control circuit of claim 5, wherein: the commutation calculation module samples a back electromotive force at an ON stage of the PWM signal.

7. The motor commutation control circuit of claim 6, wherein: the commutation set value is a percentage value of the power voltage, and the percentage value is in a positive relation with the rotating speed of the motor.

8. The motor commutation control circuit of claim 1, wherein: the motor is a brushless motor.