Motor braking device for multiple devices

Abstract

The utility model discloses a motor braking device for multiple devices, which comprises a driver and a plurality of motors, the motors are connected with the output end of the driver, the motor braking device further comprises an adjustable resistor, the motors are respectively connected with the adjustable resistor and the driver through contacts of a first contactor, the number of the motors is multiple, and the first contactor is connected with the adjustable resistor. The number of the drivers is the same as that of the motors, and the multiple motors are connected in parallel and connected with the adjustable resistor in series. According to the scheme, the size of the motor braking device of the multi-equipment system is reduced, the cost of the motor braking device of the multi-equipment system is reduced, and the optimization of the cost and the reliability can be realized without increasing the size of the multi-equipment system too much.

Description

Technical Field

[0001] The utility model relates to the technical field of motor control, in particular to a motor braking device for multiple devices. Background Art

[0002] Servo motors belong to the field of motor control. From an energy perspective, the motion system device can be regarded as an energy pool. Accordingly, the purpose of the system control scheme is to: control the electrical system to output electrical energy, and then make the system move to convert it into mechanical energy; then let the braking system work, and achieve the purpose of system deceleration by consuming mechanical energy. In the servo motor power scheme, the system includes three braking schemes: Scheme 1 is regenerative braking, which converts mechanical energy into electrical energy and feeds it back to the power grid or the device's own energy storage unit; Scheme 2 is an independent mechanical braking device, which brakes the spindle through the braking device, so that the motor's mechanical energy is converted into heat energy by friction; Scheme 3 is an external braking resistor for the motor, which converts the energy in the motor from mechanical energy to electrical energy, and then converts electrical energy into heat energy and releases it. In the existing motor braking device, one driver and one motor use a braking resistor. When multiple devices are used, the motor braking device is large in size and high in cost.

[0003] For example, Chinese patent publication number CN109743000A, publication date May 10, 2019, named "Servo motor braking circuit, servo motor braking system and braking method", includes a drive unit connected to the servo motor through a three-phase line and configured to output three-phase alternating current to control the operation of the servo motor; a braking unit coupled to the three-phase line and configured to short-circuit or disconnect two or more phases of the servo motor to perform braking protection on the servo motor.

[0004] The disadvantages of the existing patents are that one brake resistor is used for one driver and one motor in the existing motor brake device. When multiple devices are used, the motor brake device is large in size and high in cost. Utility Model Content

[0005] The purpose of the utility model is to solve the problem that in the existing motor braking device, one driver and one motor use one braking resistor respectively, resulting in a large size and high cost of the motor braking device when used in multiple devices, and to provide a motor braking device for multiple devices that reduces the size of the motor braking device and reduces the motor braking cost.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A motor brake device for multiple devices includes a driver and a motor, wherein the motor is connected to the output end of the driver, and further includes an adjustable resistor, wherein the motor is connected to the adjustable resistor and the driver through the contacts of a first contactor, wherein the number of the motors is multiple, the number of the drivers is the same as the number of the motors, and the multiple motors are connected in parallel and in series with the adjustable resistor. The motor brake device for multiple devices described in this scheme is applied to a multiple device system composed of multiple drivers and motors, wherein multiple drivers and motors share one adjustable resistor, and there is no need to use one brake resistor for each driver and motor, thereby reducing the volume of the motor brake device of the multiple device system and reducing the cost of the motor brake device of the multiple device system. In addition, the external brake resistor in this scheme adopts an adjustable resistor. In a system composed of multiple drivers and motors, if there is an uninterrupted external force load, the brake resistor will work for a long time. At this time, a heat dissipation device must be considered. When the motor brake system fails due to overheating, the device will have a great safety risk. The scheme adopts an external adjustable resistor to avoid this hidden danger. The adjustable resistor adopts an external connection and its resistance value can be appropriately adjusted according to the actual situation. The first contactor is used in this solution to improve the safety and reliability of the entire system.

[0008] When the whole machine is abnormally powered off, the first contactor connects the adjustable resistor to each motor. The adjustable resistor and the motor form a closed loop. The closed loop converts kinetic energy into thermal energy, so that the motor drags the whole machine into a passive deceleration state, or a low-speed operation state in which the heat generated by the adjustable resistor is balanced with the work done by the load; when the whole machine is powered on and the abnormality is restored, the whole machine is passively decelerated and actively reset by controlling the braking system. Through high-reliability and low-cost components such as the adjustable resistor and the first contactor, the passive safety and active recovery of the whole equipment are achieved. Compared with traditional brake systems, the multi-device system in this solution can achieve the optimization of cost and reliability without increasing too much volume, and realize a safety design solution for harsh working environments.

[0009] Preferably, the number of the first contactors is the same as the number of the motors, the first contactors correspond to the motors one by one, and the adjustable resistor is connected in series with the motors through the first contactors. The contacts of the first contactors include a normally closed contact of the first contactor and a normally open contact of the first contactor, the motor is connected to the driver through the normally closed contact of the first contactor, and the motor is connected to the adjustable resistor through the normally open contact of the first contactor.

[0010] Preferably, a controller is further included, the controller is connected to the input end of the driver, and the controller is connected to the enable end of the first contactor. The driver is powered by AC, and when the controller detects that the whole machine is abnormally powered off, the controller issues an instruction to open the normally closed contact of the first contactor and close the normally open contact of the first contactor, so that the motor and the driver are disconnected, and the first contactor connects the adjustable resistor to the motor; when the motor fails or any driver is abnormally powered off, the controller issues an instruction to connect the first contactor corresponding to the motor to the adjustable resistor.

[0011] Preferably, it also includes a plurality of second contactors, the number of the second contactors is the same as the number of the first contactors, and the second contactors are connected in series with the first contactors corresponding to the second contactors and the adjustable resistor. The second contactors include a normally open contact of the second contactor and a normally closed contact of the second contactor, and the first contactor is connected to the adjustable resistor via the normally closed contact of the second contactor. In order to prevent the first contactor from failing and affecting the operation of the entire system, several more second contactors can be used between the driver and the adjustable resistor to improve the safety and reliability of the entire system. The number of second contactors is not limited and can be one, two or more.

[0012] Preferably, a braking resistor is also included, one end of which is connected to the input end of the motor through a third contactor, and the other end is connected to the adjustable resistor. The motor is connected to the first contactor and the braking resistor respectively through the contacts of the third contactor, and the braking resistor and the first contactor are connected in parallel. On the one hand, the braking resistor enables the braking system and the adjustable resistor to be connected to the corresponding motor at the same time when a single motor in the whole system fails, and the control system performs redundant operation without affecting the normal operation of other motors; on the other hand, when the motor loads in multiple devices are different and the whole machine is abnormally powered off, the braking resistor is connected to the motor with a larger load, and the excess electrical energy is converted into heat energy and dissipated, thereby ensuring the safe and stable operation of each motor.

[0013] Preferably, the controller is connected to the enable end of the third contactor. The controller controls the corresponding third contactor of each motor, and through the cooperation of the third contactor and the first contactor, the whole machine realizes a passive deceleration state or the motor realizes a redundant state.

[0014] Preferably, the number of the braking resistor is one, and the multiple motors are connected in parallel and in series with the braking resistor. A braking resistor is used in a multi-device system, and the braking resistor is connected to each motor through the third contactor corresponding to each motor. The use of one braking resistor makes the cost of the braking resistor lower and the size smaller.

[0015] Preferably, the braking resistor is an automatic adjustable resistor, which includes a resistor and an analog switch, and the controller is connected to the analog switch. The automatic adjustable resistor is suitable for a multi-device system in which the number of driver and motor combinations is uncertain, and the resistance value and power of the provided braking resistor are also uncertain. If a braking resistor with a fixed resistance and power is used: when the braking resistor is low, the motor braking may be untimely or inaccurate, affecting the operating efficiency and accuracy of the system. The back electromotive force generated during the braking of the servo motor cannot be fully absorbed, which will damage the motor and the servo system and shorten the service life of the equipment; if the braking resistor is too large, the braking amount will be reduced, and the frequency converter may report overvoltage. Therefore, choosing a braking resistor with a fixed resistance and power may cause the resistance to be too large or too small when the number of driver and motor combinations is uncertain, while the adjustable resistor can be adjusted accordingly according to the number of different driver and motor combinations to meet system requirements.

[0016] Preferably, the number of the braking resistors is multiple, the number of the braking resistors is the same as the number of the motors, and the multiple braking resistors are connected in parallel and in series with the adjustable resistor. When the braking resistors and the motors correspond one to one, the control of the motors is more accurate, which is suitable for multi-device system control.

[0017] Preferably, a temperature sensor for detecting the temperature of the adjustable resistor is also included, and the temperature sensor is connected to the controller. The temperature sensor detects the temperature of the adjustable resistor. In a system with multiple drivers and motors, if there is an uninterrupted external force load, the adjustable resistor will work for a long time. At this time, the heat dissipation device must be considered. When the brake system overheats and fails, the equipment will have a great safety risk. In order to avoid this hidden danger, the access of the adjustable resistor and the brake resistor can be appropriately adjusted according to the actual situation to meet the system requirements.

[0018] Therefore, the utility model has the following beneficial effects: the volume of the motor brake device of the multi-device system is reduced, the cost of the motor brake device of the multi-device system is reduced, and the multi-device system can achieve the optimization of cost and reliability without increasing too much volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the first embodiment of the utility model.

[0020] Figure 2 It is a structural schematic diagram of the second embodiment of the utility model.

[0021] Figure 3 It is a structural schematic diagram of the first contactor and the second contactor in the second embodiment of the utility model.

[0022] Figure 4It is a structural schematic diagram of the first contactor in the first embodiment of the utility model.

[0023] As shown in the figure:

[0024] Driver 1, motor 2, adjustable resistor 3, first contactor 4, braking resistor 5, second contactor 6, third contactor 7. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the technical solution embodiments of the utility model clearer, the utility model is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0026] Embodiment 1, as Figure 1 , Figure 4 As shown, a motor 2 braking device for multiple devices includes a driver 1 and a motor 2, the output ends of the motor 2 and the driver 1 are connected, and also includes an adjustable resistor 3. The motor 2 is connected to the adjustable resistor 3 and the driver 1 through the contacts of the first contactor 4, the number of motors 2 is multiple, the number of drivers 1 is the same as the number of motors 2, and the multiple motors 2 are connected in parallel and in series with the adjustable resistor 3.

[0027] A motor 2 brake device for multiple devices in the above embodiment is applied to a multiple device system composed of multiple drivers 1 and motors 2. Multiple drivers 1 and motors 2 share one adjustable resistor 3, and it is no longer necessary to use one brake resistor 5 for each driver 1 and motor 2, which reduces the volume of the motor 2 brake device of the multiple device system and reduces the cost of the motor 2 brake device of the multiple device system. In addition, the external brake resistor 5 in this solution adopts an adjustable resistor 3. In a system composed of multiple drivers 1 and motors 2, if there is an uninterrupted external force load, the brake resistor 5 will work for a long time. At this time, the heat dissipation device must be considered. When the motor 2 brake system overheats and fails, the equipment will have a great safety risk. The external adjustable resistor 3 in this solution can avoid this hidden danger. The adjustable resistor 3 adopts an external connection and its resistance value can be appropriately adjusted according to the actual situation. The first contactor 4 is used in this solution to improve the safety and reliability of the entire system. The problem that one driver 1 and motor 2 in the existing motor 2 brake device use one brake resistor 5, and when multiple devices are used, the motor 2 brake device is large in size and high in cost is solved.

[0028] When the whole machine is abnormally powered off, the first contactor 4 connects the adjustable resistor 3 to each motor 2. The adjustable resistor 3 and the motor 2 form a closed loop. The closed loop converts kinetic energy into thermal energy, so that the motor 2 drags the whole machine into a passive deceleration state, or a low-speed operation state in which the heat generated by the adjustable resistor 3 is balanced with the work done by the load; when the whole machine is powered on and the abnormality is restored, the whole machine is passively decelerated and actively reset by controlling the braking system. Through high-reliability and low-cost components such as the adjustable resistor 3 and the first contactor 4, the passive safety and active recovery of the whole equipment are achieved. Compared with the traditional brake system, the multi-device system in this solution can achieve the optimization of cost and reliability without increasing too much volume, and realize the safety design solution for harsh working environments.

[0029] Specifically, Figure 1 As shown, the number of the first contactors 4 is the same as the number of the motors 2, the first contactors 4 correspond to the motors 2 one by one, and the adjustable resistor 3 is connected in series with the motors 2 through the first contactors 4. The contacts of the first contactors 4 include the normally closed contacts of the first contactors 4 and the normally open contacts of the first contactors 4, the motors 2 are connected to the driver 1 through the normally closed contacts of the first contactors 4, and the motors 2 are connected to the adjustable resistor 3 through the normally open contacts of the first contactors 4.

[0030] In this embodiment, a controller is also included, and the controller is connected to the input end of the driver 1, and the controller is connected to the enable end of the first contactor 4. The driver 1 is powered by AC, and when the controller detects that the whole machine is abnormally powered off, the controller issues a command to open the normally closed contact of the first contactor 4, and close the normally open contact of the first contactor 4, so that the motor 2 and the driver 1 are disconnected, and the first contactor 4 connects the adjustable resistor 3 to the motor 2; when the motor 2 fails or any one of the drivers 1 is abnormally powered off, the controller issues a command to connect the first contactor 4 corresponding to the motor 2 to the adjustable resistor 3 to the motor 2.

[0031] Further, such as Figure 1 As shown, it also includes a plurality of second contactors 6, the number of the second contactors 6 is the same as the number of the first contactors 4, and the second contactors 6 are connected in series with the first contactors 4 and the adjustable resistor 3 corresponding to the second contactors 6. The second contactors 6 include a normally open contact of the second contactor 6 and a normally closed contact of the second contactor 6, and the first contactor 4 is connected to the adjustable resistor 3 through the normally closed contact of the second contactor 6. In order to prevent the first contactor 4 from failing and affecting the operation of the entire system, several more second contactors 6 can be used between the driver 1 and the adjustable resistor 3, so as to improve the safety and reliability of the entire system. The number of the second contactors 6 is not limited, and can be one, two or more.

[0032] Furthermore, it also includes a temperature sensor for detecting the temperature of the adjustable resistor 3, and the temperature sensor is connected to the controller. The temperature sensor detects the temperature of the adjustable resistor 3. In a system composed of multiple drivers 1 and motors 2, if there is an uninterrupted external force load, this will cause the adjustable resistor 3 to work for a long time. At this time, the heat dissipation device must be considered. When the brake system overheats and fails, the equipment will have a great safety risk. In order to avoid this hidden danger, the access of the adjustable resistor 3 can be appropriately adjusted according to the actual situation to meet the system requirements.

[0033] The above embodiment has the following beneficial effects: the volume of the motor 2 brake device of the multi-device system is reduced, the cost of the motor 2 brake device of the multi-device system is reduced, and the multi-device system can achieve the optimization of cost and reliability without increasing too much volume.

[0034] Embodiment 2, as Figure 2 , Figure 3 As shown, a motor 2 braking device for multiple devices includes a driver 1 and a motor 2, the output ends of the motor 2 and the driver 1 are connected, and also includes an adjustable resistor 3. The motor 2 is connected to the adjustable resistor 3 and the driver 1 through the contacts of the first contactor 4, the number of motors 2 is multiple, the number of drivers 1 is the same as the number of motors 2, and the multiple motors 2 are connected in parallel and in series with the adjustable resistor 3.

[0035] When the whole machine is abnormally powered off, the first contactor 4 connects the adjustable resistor 3 to each motor 2. The adjustable resistor 3 and the motor 2 form a closed loop. The closed loop converts kinetic energy into thermal energy, so that the motor 2 drags the whole machine into a passive deceleration state, or a low-speed operation state in which the heat generated by the adjustable resistor 3 is balanced with the work done by the load; when the whole machine is powered on and the abnormality is restored, the whole machine is passively decelerated and actively reset by controlling the braking system. Through high-reliability and low-cost components such as the adjustable resistor 3 and the first contactor 4, the passive safety and active recovery of the whole equipment are achieved. Compared with the traditional brake system, the multi-device system in this solution can achieve the optimization of cost and reliability without increasing too much volume, and realize the safety design solution for harsh working environments.

[0036] In this embodiment, Figure 2 As shown, the number of the first contactors 4 is the same as the number of the motors 2, the first contactors 4 correspond to the motors 2 one by one, and the adjustable resistor 3 is connected in series with the motors 2 through the first contactors 4. The contacts of the first contactors 4 include the normally closed contacts of the first contactors 4 and the normally open contacts of the first contactors 4, the motors 2 are connected to the driver 1 through the normally closed contacts of the first contactors 4, and the motors 2 are connected to the adjustable resistor 3 through the normally open contacts of the first contactors 4.

[0037] Specifically, it also includes a controller, the controller is connected to the input end of the driver 1, and the controller is connected to the enable end of the first contactor 4. The driver 1 is powered by AC. When the controller detects that the whole machine is abnormally powered off, the controller issues a command to open the normally closed contact of the first contactor 4 and close the normally open contact of the first contactor 4, so that the motor 2 and the driver 1 are disconnected, and the first contactor 4 connects the adjustable resistor 3 to the motor 2; when the motor 2 fails or any one of the drivers 1 is abnormally powered off, the controller issues a command to connect the first contactor 4 corresponding to the motor 2 to the adjustable resistor 3 to the motor 2.

[0038] In this embodiment, Figure 2 , Figure 3 As shown, it also includes a braking resistor 5, one end of the braking resistor 5 is connected to the input end of the motor 2 through the third contactor 7, and the other end is connected to the adjustable resistor 3. The motor 2 is connected to the first contactor 4 and the braking resistor 5 through the contacts of the third contactor 7, and the braking resistor 5 and the first contactor 4 are connected in parallel. On the one hand, the braking resistor 5 enables the braking system and the adjustable resistor 3 to be connected to the corresponding motor 2 at the same time when a single motor 2 in the whole system fails, and the control system performs redundant operation without affecting the operation of other normal motors 2; on the other hand, when the loads of the motors 2 in multiple devices are different and the whole machine is abnormally powered off, the braking resistor 5 is connected to the motor 2 with a larger load, and the excess electric energy is converted into heat energy and dissipated, thereby ensuring the safe and stable operation of each motor 2. The controller is connected to the enable end of the third contactor 7. The controller controls the corresponding third contactor 7 of each motor 2, and through the cooperation of the third contactor 7 and the first contactor 4, the whole machine realizes a passive deceleration state or the motor 2 realizes a redundant state.

[0039] An implementation method of the braking resistor 5: the number of the braking resistor 5 is one, and the multiple motors 2 are connected in parallel and in series with the braking resistor 5. A braking resistor 5 is used in a multi-device system, and the braking resistor 5 is connected to each motor 2 through the corresponding third contactor 7 of each motor 2. The use of a braking resistor 5 makes the cost of the braking resistor 5 lower and the volume smaller. The braking resistor 5 is further optimized, and the braking resistor 5 is an automatic adjustable resistor 3, and the automatic adjustable resistor 3 includes a resistor and an analog switch, and the controller and the analog switch are connected. The automatic adjustable resistor 3 is used, which is suitable for the multi-device system in which the number of combinations of the driver 1 and the motor 2 is uncertain, and the resistance value of the provided braking resistor 5 and the power of the braking resistor 5 are also uncertain. If a braking resistor 5 with a fixed resistance value and power is used: when the braking resistor 5 is low, the motor 2 may be braked untimely or inaccurately, affecting the operating efficiency and accuracy of the system, and the back electromotive force generated when the servo motor 2 is braked cannot be completely absorbed, which will damage the motor 2 and the servo system and shorten the service life of the equipment; if the braking resistor 5 is too large, the braking amount will be reduced, and the frequency converter may report overvoltage. Therefore, choosing a brake resistor 5 with a fixed resistance and power may result in a resistance that is too large or too small when the number of combinations of the driver 1 and the motor 2 is uncertain, while the adjustable resistor 3 can be adjusted accordingly according to the number of different combinations of the driver 1 and the motor 2 to meet system requirements.

[0040] Another implementation of the braking resistor 5: there are multiple braking resistors 5, the number of braking resistors 5 is the same as the number of motors 2, and multiple braking resistors 5 are connected in parallel and connected in series with the adjustable resistor 3. When the braking resistors 5 and the motors 2 correspond one to one, the control of the motors 2 is more precise, which is suitable for multi-device system control.

[0041] Further optimization also includes a temperature sensor for detecting the temperature of the adjustable resistor 3, and the temperature sensor is connected to the controller. The temperature sensor detects the temperature of the adjustable resistor 3. In a system with multiple drivers 1 and motors 2, if there is an uninterrupted external force load, this will cause the adjustable resistor 3 to work for a long time. At this time, the heat dissipation device must be considered. When the brake system overheats and fails, the equipment will have a great safety risk. In order to avoid this hidden danger, the access of the adjustable resistor 3 and the brake resistor 5 can be appropriately adjusted according to the actual situation to meet the system requirements.

[0042] Furthermore, it also includes a plurality of second contactors 6, the number of the second contactors 6 is the same as the number of the first contactors 4, and the second contactors 6 are connected in series with the first contactors 4 and the adjustable resistor 3 corresponding to the second contactors 6. The second contactors 6 include a normally open contact of the second contactor 6 and a normally closed contact of the second contactor 6, and the first contactor 4 is connected to the adjustable resistor 3 through the normally closed contact of the second contactor 6. In order to prevent the first contactor 4 from failing and affecting the operation of the entire system, several more second contactors 6 can be used between the driver 1 and the adjustable resistor 3, so as to improve the safety and reliability of the entire system. The number of the second contactors 6 is not limited, and can be one, two or more.

[0043] The above embodiment has the following beneficial effects: the volume of the motor 2 brake device of the multi-device system is reduced, the cost of the motor 2 brake device of the multi-device system is reduced, and the multi-device system can achieve the optimization of cost and reliability without increasing too much volume.

[0044] The specific embodiments described above are only preferred implementations of the present invention, and are not intended to limit the specific implementation scope of the present invention. All equivalent changes made in accordance with the shape and structure of the present invention should be included in the protection scope of the present invention.

Claims

1. A motor brake device for multiple devices, comprising a driver (1) and a motor (2), wherein the motor (2) is connected to the output end of the driver (1), characterized in that: It also includes an adjustable resistor (3), the motor (2) being connected to the adjustable resistor (3) and the driver (1) respectively through the contacts of the first contactor (4), the number of the motors (2) being multiple, the number of the drivers (1) being the same as the number of the motors (2), and the multiple motors (2) being connected in parallel and in series with the adjustable resistor (3).

2. A motor brake device for multiple devices according to claim 1, characterized in that: The number of the first contactors (4) is the same as the number of the motors (2), the first contactors (4) and the motors (2) correspond one to one, and the adjustable resistor (3) is connected in series with the motor (2) via the first contactors (4).

3. A motor brake device for multiple devices according to claim 2, characterized in that: It also includes a controller, the controller is connected to the input end of the driver (1), and the controller is connected to the enable end of the first contactor (4).

4. A motor brake device for multiple devices according to claim 3, characterized in that: It also comprises a plurality of second contactors (6), the number of the second contactors (6) being the same as the number of the first contactors (4), and the second contactors (6) being connected in series with the first contactors (4) corresponding to the second contactors (6) and the adjustable resistor (3).

5. A motor brake device for multiple devices according to claim 3 or 4, characterized in that: It also includes a braking resistor (5), one end of which is connected to the input end of the motor (2) via a third contactor (7), and the other end is connected to the adjustable resistor (3); the motor (2) is connected to the first contactor (4) and the braking resistor (5) respectively via the contacts of the third contactor (7); the braking resistor (5) and the first contactor (4) are connected in parallel.

6. A motor brake device for multiple devices according to claim 5, characterized in that: The controller is connected to an enabling terminal of the third contactor (7).

7. The motor brake device for multiple devices according to claim 6 is characterized in that: The number of the braking resistor (5) is one, and the plurality of motors (2) are connected in parallel and in series with the braking resistor (5).

8. The motor brake device for multiple devices according to claim 7 is characterized in that: The braking resistor (5) is an automatically adjustable resistor (3), the automatically adjustable resistor (3) comprises a resistor and an analog switch, and the controller is connected to the analog switch.

9. The motor brake device for multiple devices according to claim 6, characterized in that: The number of the braking resistors (5) is multiple, the number of the braking resistors (5) is the same as the number of the motors (2), and the multiple braking resistors (5) are connected in parallel and in series with the adjustable resistor (3).

10. A motor brake device for multiple devices according to claim 3 or 4, characterized in that: It also includes a temperature sensor for detecting the temperature of the adjustable resistor (3), and the temperature sensor is connected to the controller.

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