CN208046490U - Actuator motor control system - Google Patents

Abstract

The utility model provides an actuator motor control system, comprising: a motor, which drives the actuator according to the driving signal of the drive circuit; a zero-crossing clock module, which generates a zero-crossing square wave signal with the same frequency as the power supply; The zero-point square wave signal generates square wave pulses for the clock reference signal; the drive circuit, including the thyristor unit and the drive unit, and the thyristor unit, changes the conduction angle of the thyristor according to the square wave pulse of the control module to adjust the voltage of the motor ; The drive unit controls the forward/reverse rotation of the motor according to the control signal of the control module; the acquisition module collects the current opening signal of the actuator; the control module compares the external opening command signal with the current opening signal of the actuator Value calculation, adjust the motor speed according to the difference calculated by the difference until the opening of the actuator is close to the difference. The utility model adopts the thyristor unit to be connected in series to drive the unit, which improves the safety when the motor is running.

Description

Actuator motor control system

technical field

The utility model relates to the technical field of motor control, in particular to an actuator motor control system.

Background technique

An electric actuator is a drive device that can provide linear or rotary motion, which uses drive energy and works under the action of a control signal. An actuator uses liquid, gas, electricity or other energy and converts it into drive action through a motor, cylinder or other device.

However, the existing motor actuator control methods mainly include the following four types:

The first is the direct control scheme of the contactor. This scheme has poor control accuracy and low adjustment frequency, and is not suitable for frequent switching control conditions. Among them, the contactor is prone to arcing and strong electromagnetic interference. At the same time, The contactor is directly started, which has a large impact on the mechanical and electrical components, reducing the service life of the mechanical and electrical components.

The second is the IGBT frequency conversion control scheme, which has segmental variable speed operation, high control accuracy, and is suitable for frequent adjustment control; however, its control software and hardware circuits are complex and technically difficult, resulting in high manufacturing costs and failures. The rate is also high.

The third type is the thyristor control scheme. When the motor power is large, it is easy to cause commutation failure during frequent forward and reverse rotations, resulting in damage to the thyristor. In addition, this scheme needs at least 5 bidirectional thyristors to realize the forward and reverse control of the motor.

The fourth is the power relay control scheme. In this scheme, the power relay has the problems of the first control scheme. Compared with contactors, the contact capacity of power relays is small, which is more likely to cause problems such as contact arcing and contact bonding.

Therefore, there is an urgent need for a motor actuator control scheme that can avoid the problem of contactor or relay contact bonding, and prevent the phenomenon of damage to the motor caused by the breakdown of the thyristor.

Utility model content

In view of the above-mentioned shortcomings of the prior art, the purpose of this utility model is to provide a motor control system for the actuator, which is used to solve the problem of soft start and stop when the actuator in the prior art is controlled by a motor. The problem of shock caused by mechanical and electrical components.

In order to achieve the above purpose and other related purposes, the utility model provides an actuator motor control system, including:

The motor, whose input end is connected to the drive circuit, and whose output end is connected to the actuator, is used to drive the actuator according to the drive signal of the drive circuit;

A zero-crossing clock module, whose input end is connected to a power supply, and whose output end is connected to the control module, is used to generate a zero-crossing square wave signal with the same frequency as the power supply;

A pulse waveform generating module, the input end of which is connected to the control module, and the output end is connected to the drive circuit, for generating square wave pulses with the square wave signal at the zero crossing point as the clock reference signal;

The drive circuit includes a thyristor unit and a drive unit, the input end of the thyristor unit is connected to the control module and the power supply, and is used to change the conduction angle of the thyristor according to the square wave pulse of the control module to adjust the voltage of the motor; The input end of the drive unit is connected to the control module and the thyristor unit, and is used to control the forward rotation or reverse rotation of the motor according to the control signal of the control module;

A collection module, the input end of which is connected to the actuator, and the output end is connected to the control module, for collecting the current opening signal of the actuator;

The control module is used to perform difference calculation between the opening command signal from the outside and the current opening signal of the actuator, and adjust the speed of the motor according to the difference calculated by the difference until the opening of the actuator is close to up to the difference.

As mentioned above, the actuator motor control system of the present invention has the following beneficial effects:

The utility model includes a thyristor unit and a drive unit, through which the voltage regulation of the motor is realized to achieve the purpose of flexible start and stop; the drive unit controls the forward and reverse rotation of the motor in a relay interlocking manner; wherein, the thyristor and The relay contacts are connected in series to control the motor. When the thyristor is completely broken down, the power supply of the motor is cut off by disconnecting the contacts of the relay, which can prevent the motor from running out of control; The method of silicon cuts off the power supply of the motor and avoids the loss of control of the motor, thereby improving the safety of the motor when it is running.

Description of drawings

Fig. 1 shows a structural block diagram of a kind of actuator motor control system provided by the utility model;

Fig. 2 shows a structural block diagram of an embodiment of an actuator motor control system provided by the utility model.

Component label description:

VT1 first thyristor

VT 2 Second thyristor

VT3 The third thyristor

KA1 first relay

KA2 second relay

1 motor

2 Zero-crossing clock module

3 pulse waveform generation module

4 drive circuit

41 Thyristor unit

42 drive unit

5 acquisition module

6 control module

7 Speed reduction mechanism

8 power

Detailed ways

The implementation of the present utility model is described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present utility model from the content disclosed in this specification. The utility model can also be implemented or applied through other different specific implementation modes, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the utility model. It should be noted that, in the case of no conflict, the following embodiments and features in the embodiments can be combined with each other.

It should be noted that the diagrams provided in the following embodiments are only schematically illustrating the basic idea of the utility model, and only the components related to the utility model are shown in the diagrams rather than the number of components, Shape and size drawing, the type, quantity and proportion of each component can be changed arbitrarily during actual implementation, and the component layout type may also be more complicated.

Please refer to Fig. 1, the utility model provides a structural block diagram of an actuator motor control system, which is described in detail as follows:

The motor 1, its input end is connected to the drive circuit 4 and the power supply 8, and its output end is connected to the actuator, which is used to drive the actuator according to the drive signal of the drive circuit;

Zero-crossing clock module 2, its input end is connected to power supply 8, and output end is connected to described control module 6, is used for generating the same zero-crossing point square wave signal as described power supply frequency;

Pulse waveform generation module 3, its input terminal is connected with control module 6, and output terminal is connected with driving circuit 4, is used for generating square wave pulse with described zero-crossing square wave signal as clock reference signal;

The drive circuit 4 includes a thyristor unit 41 and a drive unit 42. The input end of the thyristor unit 41 is connected to the control module 6 and the power supply 8, and is used to change the conduction of the thyristor according to the square wave pulse of the control module. angle to adjust the voltage of the motor; the drive unit 42, whose input end is connected to the control module 6 and the thyristor unit 41, is used to control the forward or reverse rotation of the motor according to the control signal of the control module;

Acquisition module 5, its input terminal is connected with actuator, and output terminal is connected with control module 6, is used for collecting the current opening degree signal of described actuator;

The control module 6 is used to perform difference calculation on the opening degree command signal from the outside and the current opening degree signal of the actuator, and adjust the rotation speed of the motor according to the difference calculated by the difference value to reach the opening degree of the actuator close to the difference.

Specifically, the motor 1 is a three-phase motor, preferably a three-phase asynchronous motor, wherein the preferred driving power corresponding to the motor is 8KW; the drive unit is a switch interlock circuit, so that the motor is only in forward rotation or In the reverse mode, the flexible start and stop of the motor is realized through the thyristor unit, which reduces the mechanical and electrical impact on the actuator, eliminates the phenomenon of pulling the fox of the contact during reversing, and can achieve 1200 times/min. Forward and reverse control, improve the positioning accuracy of the actuator.

Please refer to Figure 2, which is a structural block diagram of an embodiment of an actuator motor control system provided by the present invention, including:

The thyristor unit 41 includes a first triac VT1, a second triac VT2, and a third triac VT3, and the control terminals of the first, second, and third triacs are connected to The pulse waveform generating module is connected; one end of the first bidirectional thyristor VT1 is connected with the motor 1, and one end of the second and third bidirectional thyristor is connected with the input end of the drive unit 42 respectively; the other end is connected with the input end of the drive unit 42 respectively Power is connected.

The drive unit 42 includes a first relay KA1, a second relay KA2, a first wire relay coil, and a second relay coil, and the two ports of the first and second relay contacts are cross-connected to the second and third two-way switches respectively. One end of the SCR, and the other two ports of the first and second relay contacts are cross-connected to the input end of the motor respectively; the two ends of the first relay coil and the second relay coil are respectively connected to the control module.

Wherein, the actuator is provided with a deceleration mechanism 7, and the acquisition module 5 is a position sensor.

In the three-phase main circuit of the motor, three bidirectional thyristors are respectively connected in series to realize the voltage regulation control of the motor, so as to achieve the purpose of flexible start and stop. Behind any two-phase thyristor, connect the normally open contacts of two DPST high-power relays (30A contact capacity) in series to realize the forward/reverse control of the motor. According to the control command input from the outside, combined with the zero-crossing clock signal of the three-phase power supply, the control module sends pulse signals with adjustable width to the three bidirectional thyristors, thereby changing the conduction angle of the thyristors, and then realizing motor voltage regulation . The control module controls the action of the high-power relay according to the current position signal and external instructions, so as to realize the forward and reverse control of the motor. When performing forward and reverse control, first turn off the three thyristors, and then switch the relay contacts to achieve zero current and zero arc switching, which improves the reliability of phase commutation and prolongs the life of the contacts.

With the above method, the drive circuit of the motor only needs three thyristors and two relays to realize reliable control of the motor. The structure is simple, the cost is low, and the cost performance is the highest in the current control scheme. Due to the use of thyristor voltage regulation technology, flexible start and stop can be realized, which reduces the mechanical impact and current impact caused by direct start of contactors and power relays, especially for high-power motors, the effect is more obvious.

During the positioning process, when the target position is about to be reached, the motor can reach the target position at a low speed through the voltage regulation technology. For large inertia motors, the overshoot can be reduced and the positioning accuracy can be improved. Turn off the three thyristors first, and then switch the two relay contacts to realize the forward and reverse control of the motor, which can make the contacts of the relay switch with zero current, avoid the arcing and ablation of the contacts, and extend the relay Contact life. In this solution, the three thyristors are only responsible for turning on and off. Compared with the thyristor scheme in the background technology, when the motor is commutating, damage to the thyristors caused by commutation failure is avoided, and the reliability is improved. The service life of the SCR is improved, and at the same time, the number of SCRs used is reduced. Because the forward and reverse control of the motor is carried out when the motor current is zero, there is no need to consider the switching delay, so the switching frequency of the forward and reverse rotation of the motor can be increased, and a switching frequency of 1200 times/min can be achieved to meet frequent adjustments Working condition requirements. However, in the four schemes in the background technology, once the contacts of the contactor and the power relay are all adhered, the IGBT and the thyristor are all broken down, the motor will be out of control, and eventually the actuator or valve will be damaged, causing a safety accident. The consequences could be disastrous. Since this scheme adopts the method of connecting the silicon controlled rectifier and the contacts of the relay in series to control the motor, the safety of the motor during operation is enhanced. When the three thyristors are all broken down, the motor power can be cut off by disconnecting the contacts of the relay, which can prevent the motor from running out of control. In the same way, when the contacts of the relay are all adhered, the motor power can be cut off by turning off the three thyristors, which can also prevent the motor from running out of control, thereby improving the safety of the actuator.

The following is a process flow of a motor control method of an actuator provided by the present invention, including:

Step S1, collecting the current opening signal of the actuator driven by the motor, and receiving an external opening command signal;

Step S2, controlling the motor to rotate forward or reversely according to the external opening command signal and the current opening signal of the actuator;

Step S3, performing a difference calculation on the opening command signal from the outside and the current opening signal of the actuator, and adjusting the rotation speed of the motor according to the difference calculated by the difference until the opening of the actuator is close to the up to the difference;

Wherein, step S301, acquiring a power supply signal driving the motor to run, and generating a zero-crossing square wave signal with the same frequency as the power supply;

Step S302, using the zero-crossing square wave signal as a clock reference signal to generate a square wave pulse;

Step S303, changing the conduction angle of the triac connected to the motor according to the square wave pulse to adjust the voltage of the motor, using the voltage to adjust the speed of the motor until the opening of the actuator is less than or equal to the up to the difference.

Specifically, when the current opening of the actuator is about to be less than or equal to the difference, the output voltage of the thyristor is reduced, and the rotation speed of the motor is adjusted to operate at a low speed to achieve deceleration and positioning of the motor.

The first thyristor VT1, the second thyristor VT2, and the third thyristor VT3 are connected in series to the three-phase power supply, and the back of the first thyristor VT1 is directly connected to a power line of the motor. Among them, one end of the two normally open contacts of the first relay contact KA1 and the second relay contact KA2 are respectively connected behind the second thyristor VT2 and the third thyristor VT3, and the other ends of the two contacts are respectively connected, Then connect to the other two power lines of the motor to form the main circuit for controlling the motor. When the contacts of the first relay KA1 are closed, the motor rotates clockwise; when the contacts of the second relay KA2 are closed, the motor rotates counterclockwise. The three-phase power supply is input to the zero-crossing clock module 2, which generates a square wave pulse with the same frequency as the power supply, and whose rising and falling edges are exactly the zero-crossing point of the power supply. The square wave pulse is sent to the control module 6 by means of photoelectric isolation, as a clock reference for voltage regulation and conduction of the thyristor. The pulse waveform generation module 3 generates a 220KHz square wave pulse, which is sent to the gate pins of the first, second and third thyristors when the control module 6 sends a signal to turn on the thyristor, thereby controlling the thyristor Silicon voltage regulation and conduction. Using such a high frequency to trigger the thyristor multiple times can avoid the phenomenon that the thyristor cannot be reliably turned on by one trigger. When the control module 6 sends out a pulse control signal with a conduction angle from small to large, the conduction of the thyristor The on-time also gradually increases from small to maximum, so that the motor voltage gradually increases from zero to maximum, and the motor speed gradually accelerates from zero to maximum, completing a flexible acceleration start process. In the same way, the conduction angle gradually changes from maximum to zero, and the voltage of the motor also changes from maximum to zero. During this process, the motor speed also gradually decreases from maximum to zero, completing a deceleration and stop process. When the trigger pulse is not sent, the SCR is turned off and the motor stops. When the drive unit 42 receives the clockwise control signal sent by the control module 6, the coil of the relay KA1 is energized, the relay contact KA1 is pulled in, the relay contact KA2 is disconnected, and the motor rotates clockwise; when the counterclockwise control signal is received , the coil of relay KA2 is energized, the relay contact KA2 pulls in, the relay contact KA1 is disconnected, and the motor rotates counterclockwise. When no control signal is sent to the drive unit 42, all relay contacts are disconnected and the motor stops. In addition, there is an interlock circuit in the drive unit 42. In any case, when one relay is energized, the other relay will be de-energized, which ensures the reliability of the commutation of the motor and avoids commutation failure, resulting in a short circuit of the power supply. Motor 1 is a three-phase asynchronous motor, which provides a power source for the actuator. The speed reduction mechanism 7 converts the high speed and low torque of the motor into low speed and high torque to drive the valves and other loads. The acquisition module 5 is a position sensor, and the opening degree of the acquisition actuator is converted into a digital signal and sent to the control module 6 as the current real-time position (opening degree signal). The control module 6 is responsible for receiving the external opening command signal, collecting the real-time opening signal of the current actuator, collecting the zero-crossing clock pulse signal, and performing difference calculation between the external opening command signal and the current real-time opening signal of the actuator, and the output can be The SCR triggers the conduction signal, outputs the relay control signal, etc., and controls the motor to run in the direction of reducing the difference until it stops, so as to realize the opening adjustment function of the actuator.

The whole working process is as follows:

When the control module 6 receives an external opening command, it performs a difference calculation with the current real-time opening degree. When the difference exceeds the default dead zone value and is a positive number, the control module 6 controls the first drive unit 42 The contacts of the first relay KA1 are closed, and the contacts of the second relay KA2 are disconnected. The zero-crossing clock signal is used to send trigger pulses to the three thyristors. By gradually increasing the output voltage of the thyristors, the soft start of the motor is realized. After the completion, the motor runs clockwise at full voltage. When the difference between the opening command and the current real-time opening of the actuator is about to be less than or equal to the dead zone value, the motor decelerates and locates by reducing the output voltage of the thyristor. When the difference When it is less than or equal to the dead zone value, stop sending thyristor trigger pulses, turn off the three thyristors, and at the same time, disconnect the contacts of the first relay KA1, stop the operation of the motor, and complete the opening adjustment.

On the contrary, when the control module 6 receives the external opening degree command, it performs difference calculation with the current real-time opening degree. When the absolute value of the difference exceeds the default dead zone value and is a negative number, the control module 6 controls the contact of the second relay KA2 of the drive unit 42 to pull in, the contact of the first relay KA1 is disconnected, and the zero-crossing clock signal is used to send signals to the three The thyristor sends trigger pulses, and by gradually increasing the output voltage of the thyristor, the flexible start of the motor is realized. After the start is completed, the motor runs counterclockwise at full voltage. When the absolute difference between the opening command and the current real-time opening of the actuator When the value is about to be less than or equal to the dead zone value, the motor deceleration positioning is realized by reducing the output voltage of the thyristor. When the absolute value of the difference is less than or equal to the dead zone value, stop sending the thyristor trigger pulse and turn off the three At the same time, the silicon controlled rectifier disconnects the contact of the second relay KA2, stops the operation of the motor, and completes the adjustment of the opening degree.

In summary, the utility model includes a thyristor unit and a drive unit, through which the voltage regulation of the motor is realized to achieve the purpose of flexible start and stop; the drive unit controls the forward and reverse rotation of the motor in a relay interlocking manner; among them, The motor is controlled by connecting the silicon controlled rectifier in series with the contacts of the relay. When the silicon controlled rectifier is completely broken down, the power supply of the motor is cut off by disconnecting the contacts of the relay, which can prevent the motor from running out of control; when the contacts of the relay are all stuck together, By turning off the silicon controlled rectifier, the power supply of the motor is cut off to prevent the motor from running out of control, thereby improving the safety of the motor when it is running. Therefore, the utility model effectively overcomes various shortcomings in the prior art and has high industrial application value.

The above-mentioned embodiments only illustrate the principles and effects of the present utility model, but are not intended to limit the present utility model. Anyone familiar with this technology can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the utility model should still be covered by the claims of the utility model.

Claims (8)

1. An actuator motor control system, characterized in that, comprising: The motor, whose input end is connected to the drive circuit, and whose output end is connected to the actuator, is used to drive the actuator according to the drive signal of the drive circuit; A zero-crossing clock module, whose input end is connected to a power supply, and whose output end is connected to a control module, is used to generate a zero-crossing square wave signal with the same frequency as the power supply; A pulse waveform generating module, the input end of which is connected to the control module, and the output end is connected to the drive circuit, for generating square wave pulses with the square wave signal at the zero crossing point as the clock reference signal; The drive circuit includes a thyristor unit and a drive unit, the input end of the thyristor unit is connected to the control module and the power supply, and is used to change the conduction angle of the thyristor according to the square wave pulse of the control module to adjust the voltage of the motor; The input end of the drive unit is connected to the control module and the thyristor unit, and is used to control the forward rotation or reverse rotation of the motor according to the control signal of the control module; A collection module, the input end of which is connected to the actuator, and the output end is connected to the control module, for collecting the current opening signal of the actuator; The control module is used to perform difference calculation between the opening command signal from the outside and the current opening signal of the actuator, and adjust the speed of the motor according to the difference calculated by the difference until the opening of the actuator is close to up to the difference. 2. The actuator motor control system according to claim 1, wherein the motor is a three-phase motor. 3. The actuator motor control system according to claim 1 or 2, wherein the motor is a three-phase asynchronous motor. 4. The actuator motor control system according to claim 1, wherein the thyristor unit comprises a first bidirectional thyristor, a second triac and a third triac, and the first bidirectional thyristor 1. The control ends of the second and third bidirectional thyristors are connected to the pulse waveform generating module; one end of the first bidirectional thyristor is connected to the motor, and one end of the second and third bidirectional thyristors is respectively connected to the The input ends of the drive unit are connected; the other ends are respectively connected to the power supply. 5. The actuator motor control system according to claim 1, wherein the drive unit is a switch interlock circuit. 6. The actuator motor control system according to claim 1 or 5, wherein the drive unit includes a first relay, a second relay, a first relay coil and a second relay coil, and the first and second relays The two ports of the relay contacts are cross-connected to one end of the second and third bidirectional thyristors respectively, and the other two ports of the first and second relays are connected to the input ends of the motor respectively; the first relay coil and the Both ends of the second relay coil are respectively connected to the control module. 7. The actuator motor control system according to claim 1, wherein the actuator is provided with a deceleration mechanism. 8. The actuator motor control system according to claim 1, wherein the acquisition module is a position sensor.