Low-power control device for contactors based on dual-coil structure and electronic switching
By using a dual-coil structure and electronic switching module, combined with an MCU control module, the contactor achieves fast and precise switching, solving the switching time difference and jitter problems caused by mechanical motion, and improving the contactor's reliability and low power consumption performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANGHAI RENMIN ELECTRICAL APP WORKS
- Filing Date
- 2025-07-11
- Publication Date
- 2026-07-17
AI Technical Summary
Existing contactors with dual coil designs suffer from switching time differences and jitter caused by mechanical movement and mechanical components, making it impossible to achieve both low power consumption and high reliability.
It adopts a dual-coil structure, an electronic switching module, and an MCU control module. It achieves fast and precise switching between the pull-in coil and the holding coil through MOSFETs. It utilizes the high resistance characteristics of the holding coil to reduce power consumption and avoid mechanical movement and assembly errors and wear of mechanical components.
It enables fast and precise switching of the contactor, eliminates the jitter caused by mechanical factors, and significantly improves the reliability and low power consumption performance of the contactor.
Smart Images
Figure CN224519797U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of contactor technology, and in particular to a low-power control device for contactors based on a dual-coil structure and electronic switching. Background Technology
[0002] In industrial equipment, power systems, and building electrical systems, AC contactors provide efficient and stable electrical control to ensure the safe and reliable operation of equipment or systems. In the building sector, contactors can improve energy efficiency and reduce carbon emissions in the control of intelligent lighting and air conditioning systems, as well as in data center power supply systems. Therefore, there are higher requirements for the low power consumption and reliability of contactors.
[0003] Regarding the control circuit for the coil of a medium-voltage contactor, utility model patent CN111816507A provides a constant current control scheme. This scheme utilizes components such as sampling resistors, MOSFETs, and MCUs to achieve constant current control of the coil, reducing power consumption and improving reliability. However, this scheme primarily focuses on the constant current control of the coil and does not address the coordinated control of dual coils, thus failing to fully leverage the advantages of a dual-coil design.
[0004] In the field of electrical control, although contactor coil control technology has made significant progress, existing technologies still have many problems that urgently need to be solved. Traditional contactor control methods mainly rely on mechanical motion and mechanical components to achieve circuit switching, a design with obvious defects. For example, the contactor mentioned in utility model patent CN220065555U has a coil that also functions as a holding coil, resulting in a large holding current. This not only wastes electrical energy but also causes coil overheating, affecting equipment stability and service life. Furthermore, the mechanical switching method suffers from assembly errors in the micro-break switch and wear from frequent inching operations, leading to a time difference between contactor engagement and holding, which in turn causes contactor jitter during switching, reducing the contactor's reliability.
[0005] To reduce holding power consumption, most existing contactors employ a dual-coil configuration with a microswitch to achieve low holding power. The wiring method between the coils and the microswitch is as follows: Figure 3 As shown. When the contactor control terminal is energized, the coil of the normally closed contact of the micro switch S1 in series is energized, and the moving iron core begins to engage. When the moving and stationary iron cores are nearly fully engaged, the extension section of the moving iron core presses the micro switch to operate. Once the moving and stationary iron cores are fully engaged, the micro switch S1 completes the switching, the holding coil is energized, and the contactor completes the engagement action while the holding coil maintains the contactor in the holding state. In the existing technology, due to the need for mechanical movement and mechanical components to achieve circuit switching, assembly errors of the micro-break switch and wear after frequent inching operations can lead to a time difference between contactor engagement and holding switching, thus causing contactor jitter during switching and reducing the reliability of the contactor. Utility Model Content
[0006] The purpose of this invention is to overcome the defects of the prior art by providing a low-power control device for a contactor based on a dual-coil structure and electronic switching. By adopting an electronic switching module and an MCU control module, it achieves fast and accurate switching between the engaging coil and the holding coil, effectively avoiding the switching time difference problem caused by mechanical movement and assembly errors and wear of mechanical components in the prior art.
[0007] The objective of this utility model can be achieved through the following technical solutions:
[0008] This utility model provides a low-power control device for a contactor based on a dual-coil structure and electronic switching, including a contactor dual-coil module, an electronic switching module, and an MCU control module;
[0009] The contactor dual-coil module includes an engaging coil and a holding coil, wherein:
[0010] The wire diameter of the pull-in coil is larger than that of the holding coil, and the number of turns of the pull-in coil is less than that of the holding coil;
[0011] The resistance of the holding coil is greater than that of the closing coil;
[0012] The electronic switching module includes a MOSFET, the drain of which is connected to the common terminal of the pull-in coil or the holding coil, and the source of which is grounded, thereby forming a low-side drive circuit.
[0013] The MCU control module is connected to the MOSFET. The MCU control module is used to output control signals to the gate of the MOSFET and to collect the voltage signal of the target point in real time to dynamically control the electrical state of the pull-in coil and the pull-out coil.
[0014] Furthermore, the dual-coil module is connected in series, wherein:
[0015] The first end of the pull-in coil is connected to the positive voltage of the bus, and the second end of the pull-in coil is connected to the first end of the holding coil;
[0016] The second end of the holding coil is connected to ground;
[0017] The drain of the MOSFET is connected between the second end of the pull-in coil and the first end of the hold-in coil.
[0018] Furthermore, the dual-coil module adopts a parallel connection method, wherein:
[0019] The first end of the pull-in coil and the first end of the holding coil are simultaneously connected to the positive voltage of the bus.
[0020] The second end of the pull-in coil is connected to the drain of the MOSFET;
[0021] The second end of the holding coil is grounded.
[0022] Furthermore, the resistance of the holding coil is 5 to 1000 times that of the engaging coil.
[0023] Furthermore, the MOSFET is an N-channel MOSFET, and the gate of the MOSFET is connected to the GPIO pin of the MCU control module through a driving circuit.
[0024] Furthermore, the voltage signal at the target location is the power supply voltage value of the target power system or the target power equipment.
[0025] Furthermore, the MCU control module includes an ARM architecture or RISC-V architecture processor, ROM, and RAM.
[0026] Furthermore, the busbar is the main circuit that supplies power to the contactor.
[0027] In terms of technical principle, this invention achieves low-power control of the contactor through a dual-coil structure and electronic switching technology. When engagement is required, the MCU control module drives the MOSFET to conduct, energizing the engagement coil and generating a sufficiently large magnetic field to drive the moving contact of the contactor to engage. After engagement is complete, the MCU shuts off the drive signal. At this point, depending on the wiring method, using either an independent circuit for the holding coil or a series circuit with the engagement coil, only the minimum magnetic flux required to maintain the holding state needs to be provided. Since the resistance of the holding coil is much greater than that of the engagement coil, the current is significantly reduced, thereby achieving the goal of greatly reducing power consumption.
[0028] Compared with the prior art, the present invention has the following beneficial effects:
[0029] This invention achieves rapid and precise switching between the engaging and holding coils by employing an electronic switching module and an MCU control module. This effectively avoids the switching time lag issues caused by mechanical movement, assembly errors, and wear of mechanical components in existing technologies. During the engaging phase, the MCU control module controls the conduction time of the MOSFET to ensure the engaging coil can quickly establish a magnetic field, driving the contactor to engage. During the holding phase, electronic switching utilizes the high resistance of the holding coil to quickly switch to a low-power holding state. The entire process does not rely on the movement of mechanical components or complex assembly, thus eliminating contactor jitter caused by mechanical factors and significantly improving the contactor's reliability. Attached Figure Description
[0030] Figure 1 This is a schematic diagram of the dual-coil module in this utility model, which uses a series connection.
[0031] Figure 2 This is a schematic diagram of the parallel connection structure of the dual coil module in this utility model.
[0032] Figure 3 This is a schematic diagram of the wiring method between the coil and the micro switch in the prior art.
[0033] In the diagram: 1. Pull-in coil, 2. Holding coil, 3. MOSFET, 4. MCU control module. Detailed Implementation
[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Component models, material names, circuit / mechanical connection structures, control methods, algorithms, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art. The control logic involved in this utility model is a conventional technical means used by those skilled in the art and is not an innovation of this utility model.
[0035] Example 1
[0036] The contactor low-power control device based on dual-coil structure and electronic switching in this embodiment includes a contactor dual-coil module, an electronic switching module, and an MCU control module 4.
[0037] The contactor dual-coil module includes a pull-in coil 1 and a holding coil 2, wherein: the wire diameter of the pull-in coil 1 is larger than that of the holding coil 2, and the number of turns of the pull-in coil 1 is less than that of the holding coil 2; the resistance value of the holding coil 2 is greater than that of the pull-in coil 1, and the resistance value of the holding coil 2 is 5 to 1000 times that of the pull-in coil 1. The electronic switching module includes a MOSFET 3, the drain of which is connected to the common terminal of either the pull-in coil 1 or the holding coil 2, and the source of which is grounded, thereby forming a low-side drive circuit.
[0038] Specifically, this embodiment employs a dual-coil structure, comprising a thick-diameter, few-turns-count pull-in coil 1 and a thin-diameter, many-turns-count holding coil 2. This makes the resistance of the holding coil 2 significantly greater than that of the pull-in coil 1, ranging from 5 to 1000 times. This satisfies the requirement of a strong magnetic field for contactor engagement and a small magnetic field for holding. The electronic switching module includes a MOSFET 3, whose drain is connected to the common terminal of either the pull-in coil 1 or the holding coil 2, and whose source is grounded, forming a low-side drive circuit. When the contactor needs to engage, the MCU control module 4 outputs a high-level signal to drive the MOSFET 3 to conduct. The pull-in coil 1 is energized at full voltage, generating a sufficiently large magnetic field to drive the contactor's moving contact to engage. At the end of the engagement phase duration T1, the MCU control module 4 turns off the drive signal to the MOSFET 3. At this point, depending on the wiring method of the dual-coil module, when connected in series, current flows from the series circuit of the pull-in coil 1 and the holding coil 2 to the ground wire, utilizing the total resistance of the two coils to maintain minimum magnetic flux.
[0039] For specific implementation, please refer to Figure 1 The dual-coil module is connected in series, wherein: the first end of the pull-in coil 1 is connected to the positive bus voltage, and the second end of the pull-in coil 1 is connected to the first end of the holding coil 2; the second end of the holding coil 2 is connected to ground; the drain of the MOSFET 3 is connected between the second end of the pull-in coil 1 and the first end of the holding coil 2. The MCU control module 4 is connected to the MOSFET 3. The MCU control module 4 is used to output control signals to the gate of the MOSFET 3 and to acquire the voltage signal at the target point in real time to dynamically control the electrical state of the pull-in coil 1 and the holding coil 2. The voltage signal at the target point is the supply voltage value of the target power system or the target power equipment. The MCU control module 4 includes an ARM architecture or RISC-V architecture processor, ROM, and RAM.
[0040] Specifically, in principle, due to the series connection method, the first end of the pull-in coil 1 is connected to the positive voltage of the bus, and its second end is connected to the first end of the holding coil 2; the second end of the holding coil 2 is grounded. This connection method allows the pull-in coil 1 to be energized at full voltage during the pull-in phase when the drain of MOSFET 3 is connected between the second end of the pull-in coil 1 and the first end of the holding coil 2, and the MCU control module 4 outputs a high-level signal to drive MOSFET 3 to conduct, generating a sufficiently strong magnetic field to drive the moving contact of the contactor to close. After the pull-in phase ends, the MCU control module 4 turns off the drive signal to MOSFET 3. At this time, the current flows through the series circuit of the pull-in coil 1 and the holding coil 2 to the ground. Since the resistance of the holding coil 2 is much greater than that of the pull-in coil 1, the current is greatly reduced when maintaining the minimum magnetic flux required to maintain the holding state, thereby achieving low-power holding. Meanwhile, the MCU control module 4 also collects the voltage signal of the target location in real time, such as the power supply voltage value of the target power system or equipment, so as to dynamically adjust and control the electrical state of the energizing coil 1 and the holding coil 2, and ensure the reliable operation and energy-saving effect of the contactor at different stages.
[0041] In a specific implementation, the MOSFET 3 is an N-channel MOSFET, and the gate of the MOSFET 3 is connected to the GPIO pin of the MCU control module 4 through a driving circuit.
[0042] In practice, the MCU control module 4 outputs a high-level signal to drive the MOSFET 3 to conduct, the coil 1 is energized under full voltage, and continues for a preset engagement stage duration T1, driving the contactor moving contact to engage.
[0043] At the end of the pull-in phase duration T1, the MCU control module 4 turns off the drive signal to the MOSFET 3 and maintains minimum magnetic flux through the independent circuit of the holding coil 2 or the series circuit with the pull-in coil 1.
[0044] In practice, when the pull-in phase duration T1 ends, the MCU control module 4 shuts off the drive signal to MOSFET 3, and the flow path between the drain and source of MOSFET 3 is disconnected.
[0045] When a series connection is used, the current flows from the series circuit of the pull-in coil 1 and the holding coil 2 to the ground wire, and the total resistance of the two coils is used to maintain the minimum magnetic flux.
[0046] In practice, when the energizing coil 1 and the holding coil 2 need to be de-energized at the same time, the bus voltage returns to zero. At the same time, the MCU control module 4 immediately turns off the drive signal of the MOSFET 3, so that the energizing coil 1 and the holding coil 2 are de-energized at the same time. The moving iron core of the contactor is reset under the action of the return spring and the contact spring, thus completing the release action of the contactor.
[0047] In practical implementation, the busbar in this utility model refers to the main circuit that supplies power to the contactor. The busbar voltage supply is cut off by the control equipment at the next higher level, such as through a circuit breaker or a main control switch, so that the busbar voltage is reduced to zero.
[0048] In principle, when a series connection is used, the engaging coil 1 and the holding coil 2 are connected in series to form a circuit, and the current flows through the two coils before being grounded. At this time, the total resistance of the two coils determines the magnitude of the current, while the magnetic flux generated by the current maintains the holding state of the contactor. When it is necessary to cut off the power supply to both coils simultaneously, the bus voltage drops to zero, and the MCU control module 4 quickly turns off the drive signal of MOSFET 3, causing the engaging coil 1 and the holding coil 2 to be de-energized simultaneously. At this time, the moving iron core in the contactor is reset under the combined action of the return spring and the contact spring, completing the release action.
[0049] In this embodiment, by employing an electronic switching module and an MCU control module 4, rapid and precise switching between the engaging coil 1 and the holding coil 2 is achieved, effectively solving the switching time difference problem caused by mechanical movement and assembly errors and wear of mechanical components in the prior art. During the engaging phase, the MCU control module 4 precisely controls the conduction time of the MOSFET 3 to ensure that the engaging coil 1 can quickly establish a magnetic field under full voltage, driving the contactor moving contact to engage. When the engaging phase duration T1 ends, the MCU control module 4 immediately turns off the drive signal to the MOSFET 3. If it is a series connection, the current will flow through the series circuit of the engaging coil 1 and the holding coil 2, using the total resistance of the two coils to maintain minimum magnetic flux, achieving low-power holding. The entire switching process is completed by electronic components, without relying on the movement of mechanical components and complex assembly, thereby eliminating contactor jitter caused by mechanical factors and significantly improving the reliability of the contactor.
[0050] In practical applications, on industrial automated production lines, a large number of electric motors require frequent start-stop control via contactors. Taking an automotive parts production line as an example, the welding robots, conveyor belt motors, and other equipment on the line are all driven by electric motors, which are typically connected to a three-phase AC power supply system with a supply voltage of 380V. In the application scenario of this utility model, the target power equipment can be these electric motors, and the voltage signal at the target point is the supply voltage value of 380V for the motor. When the MCU control module collects the 380V supply voltage in real time and finds it to be normal, it drives the MOSFET to conduct according to the preset control logic, energizing the coil, engaging the contactor, and powering the motor to run. If, during operation, the MCU detects an abnormal supply voltage value, such as being lower than the set lower threshold (e.g., 360V) or higher than the set upper threshold (e.g., 400V), it determines a power supply fault. The MCU immediately shuts off the MOSFET drive signal, the contactor disconnects, protecting the motor from damage caused by low or overvoltage, and simultaneously sends a fault alarm signal to the production line control system to ensure the safety and reliability of the production process.
[0051] Example 2
[0052] Unlike Embodiment 1, the dual-coil module in this embodiment adopts a parallel connection method, see [link to embodiment]. Figure 2 Wherein: the first end of the pull-in coil 1 and the first end of the holding coil 2 are simultaneously connected to the positive bus voltage; the second end of the pull-in coil 1 is connected to the drain of the MOSFET 3; and the second end of the holding coil 2 is grounded. When a parallel connection is used, the current flows only from the loop of the holding coil 2 to the ground wire, and the large resistance of the holding coil 2 is used to maintain the minimum magnetic flux, thereby entering the low-power holding stage.
[0053] In principle, when using a parallel connection, the first ends of both the engaging coil 1 and the holding coil 2 are connected to the positive bus voltage, while the second end of the engaging coil 1 is connected to the drain of the MOSFET 3, and the second end of the holding coil 2 is directly grounded. During the engaging phase, the MCU control module 4 outputs a high-level signal to turn on the MOSFET 3, allowing current to flow from the positive bus voltage, forming a loop through the engaging coil 1 and MOSFET 3 to ground. The engaging coil 1, operating at full voltage, generates a strong magnetic field that drives the contactor to engage. After engagement, the MCU control module 4 turns off the drive signal of the MOSFET 3, cutting off the current path of the engaging coil 1. At this point, current flows only from the loop of the holding coil 2 to ground. Because the resistance of the holding coil 2 is much greater than that of the engaging coil 1, the current flowing through the holding coil 2 is significantly reduced under the same voltage, thus generating the minimum magnetic flux required to maintain the contactor's holding state. By increasing the resistance and reducing the current, low-power holding is achieved while ensuring reliable operation of the contactor. The entire switching process is completed by electronic components, without relying on the movement and complex assembly of mechanical components. This effectively avoids the switching time difference problem caused by mechanical movement and assembly errors and wear of mechanical components in the existing technology, eliminates the contactor jitter caused by mechanical factors, and significantly improves the reliability of the contactor.
[0054] The above description of the embodiments is provided to enable those skilled in the art to understand and use the utility model. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present utility model is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present utility model without departing from its scope should be within the protection scope of the present utility model.
Claims
1. A low power consumption control device for a contactor based on a double coil structure and electronic switching, characterized by, It includes a contactor dual coil module, an electronic switching module, and an MCU control module (4); The contactor dual-coil module includes a pull-in coil (1) and a holding coil (2), wherein: The wire diameter of the pull-in coil (1) is larger than that of the holding coil (2), and the number of turns of the pull-in coil (1) is less than that of the holding coil (2); The resistance value of the holding coil (2) is greater than that of the closing coil (1); The electronic switching module includes a MOSFET (3), the drain of the MOSFET (3) is connected to the common terminal of the pull-in coil (1) or the pull-holding coil (2), and the source of the MOSFET (3) is grounded, thereby forming a low-side drive circuit; The MCU control module (4) is connected to the MOSFET (3). The MCU control module (4) is used to output control signals to the gate of the MOSFET (3) and to collect voltage signals at the target site in real time to dynamically control the electrical state of the pull-in coil (1) and the pull-holding coil (2).
2. The low-power consumption control device of a contactor based on a double-coil structure and electronic switching according to claim 1, characterized in that, The dual-coil module is connected in series, wherein: The first end of the pull-in coil (1) is connected to the positive voltage of the bus, and the second end of the pull-in coil (1) is connected to the first end of the holding coil (2); The second end of the holding coil (2) is connected to ground; The drain of the MOSFET (3) is connected between the second end of the pull-in coil (1) and the first end of the pull-hold coil (2).
3. The low power consumption control device of a contactor based on double coil structure and electronic switching according to claim 1, characterized in that, The dual-coil module adopts a parallel connection method, wherein: The first end of the pull-in coil (1) and the first end of the holding coil (2) are simultaneously connected to the positive voltage of the bus. The second end of the pull-in coil (1) is connected to the drain of the MOSFET (3).
4. The low power consumption control device of a contactor based on double coil structure and electronic switching according to claim 3, characterized in that, The second end of the holding coil (2) is grounded.
5. The low power consumption control device of a contactor based on double coil structure and electronic switching according to claim 1, characterized in that, The resistance of the holding coil (2) is 5 to 1000 times that of the holding coil (1).
6. The low-power control device for a contactor based on a dual-coil structure and electronic switching according to claim 1, characterized in that, The MOSFET (3) is an N-channel MOS transistor.
7. The low power consumption control device of a contactor based on double coil structure and electronic switching according to claim 6, characterized in that, The gate of the MOSFET (3) is connected to the GPIO pin of the MCU control module (4) through a driving circuit.
8. The low power consumption control device of a contactor based on double coil structure and electronic switching according to claim 1, characterized in that, The voltage signal at the target location is the supply voltage value of the target power system or the target power equipment.
9. The low power consumption control device of a contactor based on double coil structure and electronic switching according to claim 1, characterized in that, The MCU control module (4) includes an ARM architecture or RISC-V architecture processor, ROM, and RAM.
10. A low-power control device for a contactor based on a dual-coil structure and electronic switching according to claim 1, characterized in that, The busbar is the main circuit that supplies power to the contactor.