Energy-saving controller for alternating current contactor coil and alternating current contactor

Abstract

The energy-saving controller is connected between a main power supply and the contactor coil, and comprises a full-wave rectification unit, an LC power factor compensation unit, a DC-DC power supply unit, an MCU processing unit and a power output unit, the full-wave rectification unit is respectively connected with the main power supply, the LC power factor compensation unit, the DC-DC power supply unit and the MCU processing unit, and the power output unit is respectively connected with the LC power factor compensation unit, the MCU processing unit and a contactor coil. Compared with the prior art, the device has the advantages of reducing electromagnetic interference, reducing energy consumption and the like.

Description

Technical Field

[0001] The utility model relates to an AC contactor, in particular to an energy-saving controller for an AC contactor coil and the AC contactor. Background Art

[0002] AC contactors are widely used in industrial and commercial environments to control motors, lighting, heating equipment, and power switches for various mechanical devices. The AC contactor operates by generating an electromagnetic field within its coil, which controls the opening and closing of the main contacts through electromagnetic attraction and release.

[0003] The power consumption of the coil in the current usage environment can be analyzed from the following aspects:

[0004] 1. High energy consumption background

[0005] - Power consumption in both closing and holding states: Traditional contactor coils require large currents in both closing and holding states. In particular, the current is highest at the instant of closing. Although the current decreases slightly in the holding state, it is still large, resulting in continuous high energy consumption.

[0006] - Frequent operation: In some automated equipment and production lines, contactors are frequently operated (frequently closing and releasing), further increasing the total energy consumption of the system.

[0007] 2. Low power factor

[0008] - Inductive load characteristics: The contactor coil is a typical inductive load, which produces phase shift and results in a low power factor for the system. A low power factor means that the system needs to draw more apparent power from the grid to meet the same active power demand, increasing grid load and losses.

[0009] - Reactive power loss: Inductive loads generate reactive power, which does not do actual work but increases the loss of current flowing through wires and equipment, reducing overall energy efficiency.

[0010] 3. Heat loss and temperature rise

[0011] - Temperature rise caused by continuous high current: During the pull-in and hold-in process of traditional contactor coils, continuous high current causes the coil temperature to rise, which in turn affects the life and performance of the contactor. Operating in a high-temperature environment accelerates the aging of the insulation material and increases the failure rate.

[0012] 4. Electromagnetic Interference (EMI)

[0013] -Electromagnetic interference impact: The contactor will generate large electromagnetic interference at the moment of closing and opening, which will affect the surrounding electronic equipment. Especially in the electronic-intensive environment, this interference may cause equipment malfunction or damage.

[0014] 5. Grid stability requirements

[0015] -Grid stability: High-energy-consuming equipment places higher demands on grid stability. Frequent high-current surges can cause grid fluctuations, impacting the normal operation of other equipment. This impact is particularly significant in areas with limited power resources or grid capacity.

[0016] 6. Environmental and economic pressures

[0017] -Environmental pressure: High-energy-consuming equipment increases overall electricity consumption, indirectly leading to more greenhouse gas emissions, which is detrimental to the environment.

[0018] - Economic costs: High energy consumption directly translates into high electricity bills. For businesses, energy costs are one of the most important operating costs. Reducing energy consumption not only saves electricity bills but also improves the economic benefits of the business.

[0019] In summary, conventional AC contactor coils in current operating environments suffer from high energy consumption, low power factor, heat loss, temperature rise, electromagnetic interference, and high grid stability requirements. These issues not only impact the efficiency and lifespan of the equipment itself, but also adversely affect the stability of the overall power system and the economic benefits of the enterprise. Therefore, it is imperative to improve contactor coil control methods, increase energy efficiency, and reduce energy consumption. Utility Model Content

[0020] The purpose of the present invention is to overcome the defects of the prior art and to provide an energy-saving controller for an AC contactor coil and an AC contactor that reduce electromagnetic interference and lower energy consumption.

[0021] The purpose of the utility model can be achieved through the following technical solutions:

[0022] An energy-saving controller for an AC contactor coil, the energy-saving controller being connected between a main power supply and the contactor coil, comprising a full-wave rectifier unit, an LC power factor compensation unit, a DC-DC power supply unit, an MCU processing unit, and a power output unit. The full-wave rectifier unit is respectively connected to the main power supply, the LC power factor compensation unit, the DC-DC power supply unit, and the MCU processing unit, and the power output unit is respectively connected to the LC power factor compensation unit, the MCU processing unit, and the contactor coil.

[0023] Among them, the LC power factor compensation unit is used to compensate the power factor on the power supply side, and the MCU processing unit adjusts the duty cycle of the PWM signal corresponding to the contactor's attraction and holding according to the size of the collected power supply voltage, and outputs the adjusted PWM signal power to the contactor coil through the power output unit.

[0024] Furthermore, the full-wave rectification unit includes a diode bridge.

[0025] Furthermore, the LC power factor compensation unit includes an inductor and a capacitor connected to each other.

[0026] Furthermore, the DC-DC power supply unit is a non-isolated high-voltage direct current conversion chip.

[0027] Furthermore, the MCU processing unit is an MCU chip with a built-in A / D converter.

[0028] Furthermore, the MCU processing unit adjusts the duty cycle so that the coil current when the contactor is closed is greater than the coil current when the contactor is held.

[0029] Furthermore, the power output unit is a MOS tube power output unit or an IGBT power output unit.

[0030] Furthermore, the main power supply is a sinusoidal AC power supply.

[0031] The utility model also provides an AC contactor, comprising the energy-saving controller for the AC contactor coil as described above.

[0032] Furthermore, a slot for adapting and installing the energy-saving controller is provided in the AC contactor.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The utility model is provided with an MCU processing unit, which can conveniently utilize the existing embedded program to adjust the duty cycle of the PWM signal according to the power supply voltage data, thereby realizing the control of the contactor coil current. At the same time, through PWM control and adjustment, the electromagnetic interference of the contactor during operation is reduced, and the impact on surrounding electronic equipment is greatly reduced.

[0035] 2. The utility model only provides the minimum current required to maintain the contactor closed during the holding period. By optimizing the design of controlling the coil current, the temperature rise of the coil in the holding state is reduced, thereby extending the service life of the contactor and improving the reliability of the system.

[0036] 3. The utility model is provided with an LC power factor compensation unit, which compensates the power factor of the whole machine through the reasonable configuration of inductance and capacitance, so that the power factor of the system is effectively improved, the reactive power is reduced, and the utilization efficiency of electric energy is improved.

[0037] 4. The utility model is provided with a DC-DC power supply unit, which efficiently converts the rectified DC power into stable low-voltage DC power to power the MCU and power output unit, reducing energy loss. The stable low-voltage DC power supply also improves the working stability of the MCU and power output unit, ensuring the reliable operation of the system.

[0038] 5. Existing contactor energy-saving devices usually use signal converters and thyristors to transmit pulse signals and power output. The signal converters require a long power-up time, usually greater than 100ms, and the conduction of the thyristor must meet two conditions, which makes the opening and closing process of the thyristor relatively slow. When the contactor is used in situations where it is frequently switched on and off, the energy saver of the existing technology will cause the contactor to release before completing the attraction action, or the contactor cannot be released quickly after attraction, resulting in very unreliable contactor operation. The present invention transmits pulse signals and power output through an MCU processing unit and a MOS tube. The MOS tube uses the field effect within the semiconductor to control the current. Its switching speed is very fast, and its drive current is small, and no additional drive circuit is required. At the same time, the MOS tube has a relatively high input DC equivalent resistance, so its power consumption is very low, and its anti-interference ability is much higher than that of the thyristor. The energy-saving controller in the utility model can complete the charging and discharging actions in just 45ms after the control circuit is energized. When applied to AC contactors, the contactors can adapt to the occasions of frequent switching, and the series of actions such as large current attraction, small current holding, and power-off rapid release are very reliable.

[0039] The energy-saving controller for the AC contactor coil of the utility model can significantly reduce energy consumption, improve the overall efficiency of the system, extend the life of the equipment, reduce electromagnetic interference to the environment, and realize intelligent energy management while ensuring the normal operation of the contactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a structural diagram of the utility model;

[0041] Figure 2 Schematic diagram of an LC power factor compensation unit in an embodiment of the present utility model;

[0042] Figure 3 Schematic diagram of a step-down chopper circuit of a DC-DC power supply unit in an embodiment of the present utility model. DETAILED DESCRIPTION

[0043] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0044] Example 1

[0045] refer to Figure 1 As shown, this embodiment provides an energy-saving controller for an AC contactor coil. The energy-saving controller is connected between a main power supply 6 and a contactor coil 7 and includes a full-wave rectifier unit 1, an LC power factor compensation unit 2, a DC-DC power supply unit 3, an MCU processing unit 4, and a power output unit 5. The full-wave rectifier unit 1 is respectively connected to the main power supply 6, the LC power factor compensation unit 2, the DC-DC power supply unit 3, and the MCU processing unit 4, and the power output unit 5 is respectively connected to the LC power factor compensation unit 2, the MCU processing unit 4, and the contactor coil 7. The LC power factor compensation unit 2 is used to compensate for the power factor on the power supply side, and the MCU processing unit 4 adjusts the duty cycle of the PWM signal corresponding to the contactor's closure and holding according to the magnitude of the collected power supply voltage, and outputs the adjusted PWM signal power to the contactor coil 7 through the power output unit 5.

[0046] The full-wave rectifier 1 is used to rectify the AC power supply voltage (e.g., 220V AC) into a pulsating DC voltage. In a specific embodiment, the main components of the full-wave rectifier 1 include a diode bridge, which converts both the positive and negative half-cycles of the AC voltage into a positive pulsating DC voltage. This is the initial power processing part of the entire system.

[0047] The LC power factor compensation unit 2 is used to adjust the power factor of the entire system. Figure 2 As shown, the LC power factor compensation unit 2 of this embodiment includes an inductor L and a capacitor C. The inductor L and the capacitor C are connected and connected to the full-wave rectifier unit 1. The two ends of the capacitor C are voltage output terminals, which are connected to the power output unit 5. By properly selecting the values ​​of the inductor and the capacitor, the power factor can be compensated on the power supply side, increasing the active power (i.e., actual power) and reducing the apparent power (including reactive power), thereby improving the utilization efficiency of electric energy.

[0048] In a specific embodiment, the DC-DC power supply unit 3 is a non-isolated high-voltage DC conversion chip that can efficiently convert high-voltage DC into low-voltage DC, and convert the pulsating DC voltage rectified by the main power supply into a stable low-voltage DC power supply to power the MCU processing unit and the power output unit.

[0049] In this embodiment, the DC-DC power supply unit 3 is provided with a non-isolated DC buck circuit, also known as a non-isolated buck chopper circuit. Figure 3As shown, the chopper circuit regulates the output voltage by switching transistors on and off, converting the high DC input voltage into a stable low-voltage DC voltage to power the MCU and power output unit. The circuit board also houses the MCU processing unit and the MOSFET power output unit. This unit acquires the main power supply voltage through A / D conversion and adjusts the duty cycle of the PWM signals for both the pull-in and hold functions based on the power supply voltage, thereby controlling the power consumption of the contactor during and after closing. When the electromagnetic control system is powered and the moving and static cores are fully closed, the circuit board's microcontroller accurately collects and processes the power supply voltage data to intelligently adjust the PWM signal's duty cycle. Setting a lower duty cycle ensures a shorter high-level output and a longer low-level output from the electromagnetic control system. At this point, the MOSFET controls the drain current at its output using the voltage applied to its input gate. Rapid switching ensures precise control of the contactor coil, reducing the holding current through the coil compared to when it is closed. This reduces power consumption while ensuring reliable contactor closure, improving the contactor's energy efficiency and reducing the overall energy consumption of the power distribution system. When the contactor is reliably closed, the duty cycle is used to adjust the voltage and the MOS tube to efficiently control the large current, accurately reduce the holding current, and effectively reduce the coil temperature rise when the contactor is working.

[0050] MCU processing unit 4 is an MCU chip with a built-in A / D converter. This MCU uses the built-in A / D converter to collect the main power supply voltage and adjusts the duty cycle of the pull-in and hold PWM signals based on the power supply voltage. The pull-in PWM signal is used to initially close the contactor coil and requires a high current; the hold PWM signal is used to maintain the contactor coil closed and requires a low current. By adjusting the PWM signal's duty cycle, the coil current can be precisely controlled, thereby achieving energy savings.

[0051] In a specific embodiment, the power output unit 5 can be a MOS transistor power output unit or an IGBT power output unit. The power output unit 5 receives a PWM signal from the MCU and adjusts the power output to the contactor coil based on the PWM signal's duty cycle. As power switching devices, MOS transistors or IGBTs can efficiently control large currents and achieve precise control of the contactor coil current through rapid switching.

[0052] In a specific embodiment, the main power source 6 is a sinusoidal AC power source.

[0053] The working process of the above energy saver includes:

[0054] 1) When AC power is connected, the full-wave rectifier unit converts AC power into pulsating DC power;

[0055] 2) The LC power factor compensation unit performs power factor compensation on the rectified voltage to improve the power utilization efficiency of the system;

[0056] 3) The DC-DC power supply unit converts pulsating DC power into stable low-voltage DC power to power the MCU processing unit and power output unit;

[0057] 4) The MCU processing unit collects the main power supply voltage and adjusts the duty cycle of the PWM signal for closing and holding so that the coil current when the contactor is closed is greater than the coil current when the contactor is held;

[0058] 5) The power output unit adjusts the current output to the contactor coil according to the PWM signal output by the MCU processing unit, providing a larger current during initial attraction and a smaller current during holding to save energy.

[0059] Through the above process, the energy-saving controller of the AC contactor coil can significantly reduce energy consumption and improve the overall efficiency of the system while ensuring the normal operation of the contactor.

[0060] Example 2

[0061] This embodiment provides an AC contactor, including the energy-saving controller for the AC contactor coil as described in Example 1. In a specific implementation, a slot for fitting the energy-saving controller is provided in the AC contactor to reduce the overall size of the AC contactor.

[0062] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art based on the concepts of the present invention through logical analysis, reasoning, or limited experimentation based on the existing technology should be within the scope of protection defined by the claims.

Claims

1. An energy-saving controller for an AC contactor coil, characterized in that: The energy-saving controller is connected between a main power supply (6) and a contactor coil (7), and comprises a full-wave rectifier unit (1), an LC power factor compensation unit (2), a DC-DC power supply unit (3), an MCU processing unit (4), and a power output unit (5). The full-wave rectifier unit (1) is respectively connected to the main power supply (6), the LC power factor compensation unit (2), the DC-DC power supply unit (3), and the MCU processing unit (4), and the power output unit (5) is respectively connected to the LC power factor compensation unit (2), the MCU processing unit (4), and the contactor coil (7).

2. The energy-saving controller for AC contactor coil according to claim 1, characterized in that: The full-wave rectification unit (1) comprises a diode bridge.

3. The energy-saving controller for AC contactor coil according to claim 1, characterized in that: The LC power factor compensation unit (2) comprises an inductor and a capacitor connected to each other.

4. The energy-saving controller for AC contactor coil according to claim 1, characterized in that: The DC-DC power supply unit (3) is a non-isolated high-voltage direct current conversion chip.

5. The energy-saving controller for AC contactor coil according to claim 1, characterized in that: The MCU processing unit (4) is an MCU chip with a built-in A / D converter.

6. The energy-saving controller for AC contactor coil according to claim 1, characterized in that: By adjusting the duty cycle of the PWM signal by the MCU processing unit (4), the coil current when the contactor is closed is greater than the coil current when the contactor is held.

7. The energy-saving controller for AC contactor coil according to claim 1, characterized in that: The power output unit (5) is a MOS tube power output unit or an IGBT power output unit.

8. The energy-saving controller for AC contactor coil according to claim 1, characterized in that: The main power supply (6) is a sinusoidal AC power supply.

9. An AC contactor, characterized in that: The invention comprises an energy-saving controller for an AC contactor coil as described in any one of claims 1 to 8.

10. The AC contactor according to claim 9, characterized in that: The AC contactor is provided with a slot for adapting and installing the energy-saving controller.

Images