Power supply circuit and switching device

Abstract

The application discloses a power supply circuit and a switching device, the power supply circuit comprising a linear voltage reduction module, a mutual inductance power supply module and a control module; the mutual inductance power supply module is connected with a DC bus, the linear voltage reduction module and the control module respectively, and is used for generating an induced voltage based on the pulsating current on the DC bus when the control module adjusts the coil current, outputting a second power supply voltage to the control module according to the induced voltage, and generating an off signal to make the linear voltage reduction module stop working when the second power supply voltage reaches a preset voltage value. In the application, the mutual inductance power supply module supplies power for the control module at high voltage, and generates an off signal to close the linear voltage reduction module, so that the temperature rise of the linear voltage reduction module at high voltage can be reduced, the serious heating of the linear voltage reduction module can be avoided, and the power supply safety and reliability are improved.

Description

Technical Field

[0001] This application relates to the field of contactor technology, and more particularly to a power supply circuit and switching device. Background Technology

[0002] A wide-voltage contactor is an electrical switch that can adapt to a wide range of voltage fluctuations. Its core function is to control the switching on and off of high-power equipment (such as motors and large electrical appliances). It can also work stably under fluctuating voltage conditions and will not "break down" or be damaged when the voltage exceeds the normal range.

[0003] Wide-voltage contactors in related technologies mostly use linear buck circuits to power microcontrollers, driver circuits, etc. However, as the input voltage increases, the linear buck circuit needs to consume more electrical energy to ensure a stable output voltage, resulting in severe overheating of the electronic components in the linear buck circuit and making it prone to failure. Utility Model Content

[0004] In view of the above problems, this application provides a power supply circuit and a switching device to solve the above technical problems.

[0005] In a first aspect, this application provides a power supply circuit, which includes a linear step-down module, a mutual inductance power supply module, and a control module. The linear step-down module is connected to a DC bus and is used to step down the DC voltage on the DC bus to obtain a first supply voltage, which is output to the control module to power the control module. The control module is connected to the DC bus and a conductive coil connected to the DC bus, and is used to generate a control signal based on the DC voltage and output it to the conductive coil to adjust the coil current. The mutual inductance power supply module is connected to the DC bus, the linear step-down module, and the control module, and is used to generate an induced voltage based on the pulsating current on the DC bus when the control module adjusts the coil current, and to obtain a second supply voltage based on the induced voltage and output it to the control module to power the control module. When the second supply voltage reaches a preset voltage value, it generates a shutdown signal and outputs it to the linear step-down module to stop the linear step-down module from working.

[0006] In one possible implementation of this application, the mutual inductance power supply module includes an induction unit, a rectifier output unit, and a voltage comparison unit; the induction unit is connected to the DC bus and the rectifier output unit, and is used to generate an induced voltage based on the pulsating current on the DC bus and output it to the rectifier output unit; the rectifier output unit is connected to the control module and the voltage comparison unit respectively, and is used to rectify the induced voltage to obtain a second power supply voltage and output it to the control module and the voltage comparison unit; the voltage comparison unit is used to generate a turn-off signal and output it to the linear buck module when the second power supply voltage reaches a preset voltage value.

[0007] In one possible implementation of this application, the sensing unit includes a first current transformer, and the rectifier output unit includes a first rectifier bridge, a first capacitor, and a first diode; the primary winding of the first current transformer is connected to a DC bus, and the secondary winding of the first current transformer is connected to the third and fourth terminals of the first rectifier bridge, respectively; the first terminal of the first rectifier bridge is connected to the first terminal of the first capacitor and the anode of the first diode, the cathode of the first diode is connected to a control module, and the second terminal of the first rectifier bridge and the second terminal of the first capacitor are grounded.

[0008] In one possible implementation of this application, the voltage comparison unit includes a first Zener diode, a first resistor, and a first switching transistor; the cathode of the first Zener diode is connected to the rectifier output unit, the anode of the first Zener diode is connected to the first terminal of the first resistor and the control terminal of the first switching transistor, the first terminal of the first switching transistor is connected to the linear buck module, and the second terminal of the first resistor and the second terminal of the first switching transistor are grounded.

[0009] In one possible implementation of this application, the control module includes a voltage sampling unit, a main control unit, and a drive unit. The voltage sampling unit is connected to both the DC bus and the main control unit, and is used to sample the DC voltage and output the sampled voltage to the main control unit. The main control unit is connected to the drive unit and is used to generate a modulation signal based on the sampled voltage and output it to the drive unit. The drive unit is connected to a power switch connected in series with the conductive coil and is used to generate a control signal based on the modulation signal and output it to the power switch, so as to regulate the coil current by controlling the switching state of the power switch.

[0010] In one possible implementation of this application, the voltage sampling unit includes a first voltage divider resistor string, a second capacitor, and a first TVS diode; the first end of the first voltage divider resistor string is connected to the DC bus, the voltage divider node of the first voltage divider resistor string is connected to the first end of the second capacitor, the first end of the first TVS diode, and the sampling input terminal of the main control unit, and the second end of the first voltage divider resistor string, the second end of the second capacitor, and the second end of the first TVS diode are grounded.

[0011] In one possible implementation of this application, the control module further includes a voltage conversion unit; the voltage conversion unit is connected to the linear step-down module, the mutual inductance power supply module and the main control unit respectively, and is used to convert the first supply voltage or the second supply voltage into a working voltage and output it to the power supply terminal of the main control unit to power the main control unit.

[0012] In one possible implementation of this application, the control module further includes a state sampling unit; the state sampling unit is connected to the mutual inductance power supply module, the linear step-down module and the main control unit respectively, and is used to generate a first state voltage based on the DC voltage and output it to the main control unit when the mutual inductance power supply module does not generate a turn-off signal, and to generate a second state voltage based on the turn-off signal and output it to the main control unit when the mutual inductance power supply module generates a turn-off signal.

[0013] In one possible implementation of this application, the power supply circuit further includes an anti-interference rectifier module connected to the DC bus, which is used to perform anti-interference and rectification processing on the input AC voltage to obtain a DC voltage output to the DC bus.

[0014] Secondly, this application also provides a switching device, including a conductive coil and a power supply circuit in any possible implementation of the first aspect.

[0015] From the above, it can be concluded that this application has the following beneficial effects:

[0016] In this application, when the control module adjusts the coil current, the mutual inductance power supply module generates an induced voltage based on the pulsating current on the DC bus, thereby obtaining a second power supply voltage to power the control module. When the second power supply voltage reaches a preset voltage value, a shutdown signal is also generated to control the linear buck module to stop working, and the power supply is completely supplied by the mutual inductance power supply module. This can reduce the temperature rise of the linear buck module under high voltage, avoid its serious overheating, and thus improve the safety and reliability of power supply. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a power supply circuit provided in an embodiment of this application;

[0019] Figure 2 This is a schematic diagram of a mutual inductance power supply module provided in an embodiment of this application;

[0020] Figure 3 This is a schematic diagram of the circuit principle of the mutual inductance power supply module and the linear step-down module provided in the embodiments of this application;

[0021] Figure 4 This is a schematic diagram of a control module provided in an embodiment of this application;

[0022] Figure 5 This is a schematic diagram of the circuit principle of a voltage sampling unit provided in the embodiments of this application;

[0023] Figure 6 This is a schematic diagram of a circuit principle of the control module provided in the embodiments of this application;

[0024] Figure 7 This is another schematic diagram of the power supply circuit provided in the embodiments of this application;

[0025] Figure 8 This is a schematic diagram of the circuit principle of an anti-interference rectifier module provided in the embodiments of this application. Detailed Implementation

[0026] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0027] To enable those skilled in the art to better understand the solutions of this application, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0028] In the embodiments of this application, it should be noted that, in this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0029] Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0030] In the description of the embodiments of this application, the words "example" or "for example" are used to indicate exemplification, illustration, or description. Any embodiment or design described as "example" or "for example" in the embodiments of this application is not to be construed as being more preferred or having more advantages than another embodiment or design. The use of the words "example" or "for example" is intended to present relative concepts in a clear manner.

[0031] Furthermore, in the embodiments of this application, "multiple" refers to two or more. Therefore, in the embodiments of this application, "multiple" can also be understood as "at least two". "At least one" can be understood as one or more, such as one, two, or more. For example, including at least one means including one, two, or more, and is not limited to which ones are included. For example, including at least one of A, B, and C, then it could include A, B, C, A and B, A and C, B and C, or A and B and C.

[0032] It should be noted that in the embodiments of this application, "connection" can be understood as electrical connection. The connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0033] Before introducing the power supply circuit and switching device of this application, we will first introduce the relevant background information of the embodiments of this application.

[0034] Most current wide-voltage contactors use linear buck circuits to power microcontrollers, driver circuits, etc. However, as the input voltage increases, the voltage difference between the input and output voltage becomes larger, which increases the losses in the linear buck circuit. This leads to severe overheating of the electronic components in the linear buck circuit and makes it prone to failure.

[0035] Because wide-voltage contactors typically use pulse-width modulation (PWM) on the coil during the holding phase, the coil current can maintain a constant current over a wide voltage range, thus ensuring the contactor remains in a stable holding state.

[0036] Because of PWM modulation, the current on the DC bus changes periodically with the frequency of PWM modulation. Based on this, this application provides a power supply circuit and switching device that utilizes the characteristic of the DC bus current changing periodically with the frequency of PWM modulation. A mutual inductance power supply module is installed on the DC bus to generate mutual inductance energy, which is used to power the control module. When high voltage is input, the linear buck converter is shut down, thus solving the problem of temperature rise in the linear buck converter under high voltage.

[0037] The power supply circuit and switching device provided in this application will be described in detail below.

[0038] First, this application provides a power supply circuit, please refer to... Figure 1 , Figure 1 This is a schematic diagram of a power supply circuit provided in an embodiment of this application. The power supply circuit 10 may include a linear step-down module 100, a mutual inductance power supply module 200, and a control module 300. The linear step-down module 100 is connected to the DC bus and can be used to step down the DC voltage DC_BUS on the DC bus to obtain a first supply voltage, which is then output to the control module 300 to power the control module 300. The control module 300 is connected to both the DC bus and a conductive coil 21 connected to the DC bus, and can generate a control signal based on the DC voltage DC_BUS and output it to the conductive coil 21 to adjust the coil current. The mutual inductance power supply module 200 is connected to the DC bus, the linear step-down module 100 and the control module 300 respectively. It can be used to generate an induced voltage based on the pulsating current on the DC bus when the control module 300 adjusts the coil current, and to obtain a second power supply voltage based on the induced voltage and output it to the control module 300 to power the control module 300. When the second power supply voltage reaches a preset voltage value, it generates a turn-off signal and outputs it to the linear step-down module 100 to stop the linear step-down module 100 from working.

[0039] In this embodiment, the conductive coil 21 may be the coil of an electrical switch such as a wide-voltage contactor or circuit breaker, and the conductive coil 21 is connected in series with the DC bus.

[0040] The linear buck module 100 can be implemented using any existing linear buck circuit. The linear buck module 100 can linearly step down the DC voltage DC_BUS to generate a first supply voltage to supply power to the control module 300.

[0041] In order to keep the coil current constant over a wide voltage range, the control module 300 can sample the DC voltage DC_BUS and generate a corresponding control signal based on the magnitude of the DC voltage DC_BUS, which is then output to the conductive coil 21. The control signal is used to perform PWM regulation of the coil current to ensure that the contactor maintains a stable state.

[0042] During the PWM modulation of the coil current, the current on the DC bus changes periodically with the frequency of the PWM modulation. Therefore, the mutual inductance power supply module 200 connected to the DC bus can sense the rapidly pulsating current on the DC bus, thereby generating an induced voltage. This induced voltage is processed into a second power supply voltage and supplied to the control module 300 to power it. When the second power supply voltage rises to a preset voltage value, the mutual inductance power supply module 200 can output a shutdown signal to the linear buck module 100 to control the linear buck module 100 to turn off, thereby reducing the temperature rise of the linear buck module 100 and preventing it from overheating.

[0043] In other words, in the initial stage, when the conductive coil 21 is connected to the DC bus, the current change rate of the DC bus is small at this stage, and the induced voltage that the mutual inductance power supply module 200 can sense is small, which cannot maintain the power supply of the control module 300. Therefore, the linear step-down module 100 supplies power to the control module 300.

[0044] As the input voltage increases, the control module 300 begins to apply PWM modulation to the coil current, changing the rate of change of the current in the conductive coil 21, causing the current on the DC bus to change periodically. At this time, the mutual inductance power supply module 200 operates normally. When the induced voltage generated by the mutual inductance power supply module 200 reaches a certain value, the mutual inductance power supply module 200 outputs a shutdown signal to turn off the linear step-down module 100, preventing it from overheating. At this point, the mutual inductance power supply module 200 supplies power to the control module 300.

[0045] When the induced voltage decreases to less than a certain value, the mutual inductance power supply module 200 stops outputting the shutdown signal, and the linear step-down module 100 restarts to supply power to the control module 300.

[0046] Understandably, when the power supply is stable, the second power supply voltage can be equal to the first power supply voltage to ensure that the control module 300 can be powered on and operate normally. This preset voltage value can be set according to the actual application scenario, and is not limited here.

[0047] In this embodiment, when the control module 300 adjusts the coil current, the mutual inductance power supply module 200 generates an induced voltage based on the pulsating current on the DC bus, thereby obtaining a second power supply voltage to power the control module 300. When the second power supply voltage reaches a preset voltage value, a shutdown signal is also generated to control the linear step-down module 100 to stop working, and the power supply module 200 provides power entirely. This can reduce the temperature rise of the linear step-down module 100 under high voltage, avoid its severe overheating, and thus improve the safety and reliability of power supply.

[0048] Next, continue with Figure 1The unit modules shown are described in detail, as well as the specific implementation methods that may be used in practical applications.

[0049] like Figure 2 As shown, in some embodiments of this application, the mutual inductance power supply module 200 may include an induction unit 210, a rectifier output unit 220, and a voltage comparison unit 230; the induction unit 210 is connected to the DC bus and the rectifier output unit 220, and can be used to generate an induced voltage based on the pulsating current on the DC bus and output it to the rectifier output unit 220; the rectifier output unit 220 is connected to the control module 300 and the voltage comparison unit 230 respectively, and can be used to rectify the induced voltage to obtain a second power supply voltage and output it to the control module 300 and the voltage comparison unit 230; the voltage comparison unit 230 can be used to generate a turn-off signal and output it to the linear buck module 100 when the second power supply voltage reaches a preset voltage value.

[0050] In this embodiment, the sensing unit 210 can be connected to the DC bus. When the control module 300 performs PWM adjustment on the conductive coil 21, a corresponding induced voltage is generated based on the rapidly pulsating current on the DC bus and output to the rectifier output unit 220. It can be understood that the induced voltage here changes periodically, just like the current on the DC bus, which is an AC voltage.

[0051] After receiving the induced voltage, the rectifier output unit 220 can perform rectification, voltage regulation and other processing to obtain a second power supply voltage to power the control module 300.

[0052] The voltage comparison unit 230 is connected to the rectifier output unit 220 and can compare the second supply voltage with the preset voltage value. When the second supply voltage is less than the preset voltage value, it can be considered that the mutual inductance power supply module 200 alone cannot maintain the power supply of the control module 300. Therefore, the voltage comparison unit 230 will not output a shutdown signal to turn off the linear buck module 100. At this time, the linear buck module 100 supplies power to the control module 300.

[0053] When the second supply voltage is greater than the preset voltage value, it can be assumed that the mutual inductance power supply module 200 can independently supply power to the control module 300. Therefore, the voltage comparison unit 230 outputs a shutdown signal to control the linear step-down module 100 to shut down and stop outputting the first supply voltage to provide power to the control module 300. At this time, the second supply voltage output by the rectifier output unit 220 provides power to the control module 300.

[0054] like Figure 3As shown, in some embodiments of this application, the sensing unit 210 includes a first current transformer L1, and the rectifier output unit 220 includes a first rectifier bridge BR1, a first capacitor C1, and a first diode D1; the primary winding of the first current transformer L1 is connected to the DC bus, and the secondary winding of the first current transformer L1 is connected to the third and fourth terminals of the first rectifier bridge BR1 respectively; the first terminal of the first rectifier bridge BR1 is connected to the first terminal of the first capacitor C1 and the anode of the first diode D1 respectively, the cathode of the first diode D1 is connected to the control module 300, and the second terminal of the first rectifier bridge BR1 and the second terminal of the first capacitor C1 are grounded to GND.

[0055] As an example, the stabilized second power supply voltage is +12V, that is, the rectifier output unit 220 outputs +12V voltage to power the control module 300.

[0056] In this embodiment, the first current transformer L1 can be implemented using any existing current transformer. The first current transformer L1 can sense the rapidly pulsating current on the DC bus, thereby generating a corresponding induced voltage output to the first rectifier bridge BR1. After the induced voltage is rectified by the first rectifier bridge BR1 and regulated by the first capacitor C1, the second power supply voltage is obtained and output to the control module 300 through the first diode D1.

[0057] Please continue reading. Figure 3 In some embodiments of this application, the voltage comparison unit 230 includes a first Zener diode U1, a first resistor R1, and a first switch Q1; the cathode of the first Zener diode U1 is connected to the first end of the rectifier output unit 220, the anode of the first Zener diode U1 is connected to the first end of the first resistor R1 and the control end of the first switch Q1, the first end of the first switch Q1 is connected to the linear buck module 100, and the second end of the first resistor R1 and the second end of the first switch Q1 are grounded to GND.

[0058] In this embodiment, the first Zener diode U1 can be implemented using any existing Zener diode, and the first switching transistor Q1 can be implemented using any existing controllable switching device, including but not limited to transistors, silicon controlled rectifiers, insulated gate bipolar transistors (IGBTs), metal-oxide-semiconductor field-effect transistors (MOSFETs), etc. The specific implementation can be determined according to the actual application scenario, and is not limited here.

[0059] For example, the first switching transistor Q1 is implemented using an NPN transistor, with a preset voltage value being the regulated voltage of the first Zener diode U1, such as 2.5V. The first Zener diode U1 can compare the voltage of the second supply voltage, i.e., the voltage of the first capacitor C1, with its regulated voltage value. When the voltage of the first capacitor C1 is less than the regulated voltage value, the first Zener diode U1 is in the off state. When the voltage of the first capacitor C1 increases to be greater than the regulated voltage value, the first Zener diode U1 is turned on. Since the voltage after the first Zener diode U1 is turned on is greater than the turn-on voltage of the first switching transistor Q1, the first switching transistor Q1 is turned on, outputting a low-level turn-off signal to the linear buck module 100, controlling the linear buck module 100 to stop working. At this time, the mutual inductance power supply module 200 outputs a +12V voltage to power the control module 300.

[0060] In this embodiment, the linear buck module 100 can be implemented using any existing linear buck circuit. For example... Figure 3 As shown, as an example, the linear buck module 100 includes an eleventh resistor R11, a twelfth resistor R12, a second Zener diode U2, a fifteenth resistor R15, a second switch Q2, a sixteenth resistor R16, a third switch Q3, a tenth capacitor C10, a second TVS diode TVS2, and an eleventh capacitor C11.

[0061] The eleventh resistor R11 and the twelfth resistor R12 are connected in series and connected to the cathode of the second Zener diode U2 and the control terminal of the third switch Q3. The connection node of the eleventh resistor R11 and the twelfth resistor R12 is connected to the control terminal of the second switch Q2. The first terminal of the second switch Q2 is connected to the fifteenth resistor R15 connected to the DC bus. The second terminal of the second switch Q2 is connected to the first terminal of the sixteenth resistor R16. The second terminal of the sixteenth resistor R16 is connected to the first terminal of the third switch Q3. The second terminal of the third switch Q3 is connected to the tenth capacitor C10, the second TVS diode TVS2, the eleventh capacitor C11, and the control module 300.

[0062] In this embodiment, during the initial stage, when the DC voltage DC_BUS on the DC bus is greater than the regulated voltage of the second Zener diode U2, the second switch Q2 and the third switch Q3 are turned on, and the loop current is adjusted in real time to maintain a stable first supply voltage, such as +12V, to the control module 300.

[0063] Assuming the DC voltage DC_BUS is 25V, the control module 300 requires a first supply voltage of +12V. The linear buck module 100 needs the fifteenth resistor R15, the second switch Q2, the sixteenth resistor R16, and the third switch Q3 to bear the 13V voltage difference. That is, when the current flows from the input through the fifteenth resistor R15, the second switch Q2, the sixteenth resistor R16, and the third switch Q3, these components will consume the corresponding 13V of electrical energy. Most of the consumed electrical energy is converted into heat, and the remaining 12V is supplied to the control module 300.

[0064] As the DC voltage DC_BUS increases, the fifteenth resistor R15, the second switch Q2, the sixteenth resistor R16, and the third switch Q3 require more power, resulting in a greater temperature rise. Therefore, the mutual inductance power supply module 200 can output a low-level shutdown signal to pull down the third switch Q3, turning it off. This causes the linear buck module 100 to stop working, and the temperatures of the fifteenth resistor R15, the second switch Q2, the sixteenth resistor R16, and the third switch Q3 decrease, preventing severe overheating.

[0065] When the mutual inductance power supply module 200 is insufficient to provide power to the control module 300, the first switching transistor Q1 is turned off and no longer outputs a low-level turn-off signal. At this time, the linear buck module 100 turns on again to provide power to the control module 300. This switching of power supply can avoid the linear buck module 100 from overheating and improve the reliability and safety of the power supply.

[0066] like Figure 4 As shown, in some embodiments of this application, the control module 300 may include a voltage sampling unit 310, a main control unit 320, and a drive unit 330. The voltage sampling unit 310 is connected to the DC bus and the main control unit 320 respectively, and is used to sample the DC voltage and output the sampled voltage to the main control unit 320 based on the DC voltage. The main control unit 320 is connected to the drive unit 330 and can be used to generate a modulation signal based on the sampled voltage and output it to the drive unit 330. The drive unit 330 is connected to the power switch 22 connected in series with the conductive coil 21 and can be used to generate a control signal based on the modulation signal and output it to the power switch 22, so as to regulate the coil current by controlling the switching state of the power switch 22.

[0067] In this embodiment, the voltage sampling unit 310 can be implemented using any existing voltage sampling circuit, such as a resistor divider circuit. The voltage sampling unit 310 is connected to the DC bus and can sample the DC voltage DC_BUS, divide the DC voltage DC_BUS, and output the corresponding sampled voltage to the main control unit 320.

[0068] The main control unit 320 can be implemented using any existing microcontroller unit (MCU). The main control unit 320 can generate a corresponding modulation signal based on the magnitude of the received sampled voltage and output it to the drive unit 330. This modulation signal can be a PWM signal with an adjustable duty cycle.

[0069] Since the modulation signal output by the main control unit 320 is usually a low-voltage (typically 3.3V or 5V) and low-current (generally only a few milliamps to tens of milliamps) "weak signal", it cannot directly drive the power switch 22. Therefore, the drive unit 330 can amplify the received modulation signal and convert the "weak signal" into a high-voltage (e.g., 12V, 15V, etc.) and high-current (hundreds of milliamps) "strong signal", i.e., a control signal, to quickly "charge and discharge" the gate of the power switch 22, allowing the power switch 22 to be instantly and completely turned on or off, thus avoiding overheating and improving efficiency.

[0070] The driving unit 330 in this embodiment can be implemented using any existing driving chip. The driving unit 330 amplifies the modulation signal into a control signal and outputs it to the power switch 22 to control the power switch 22 to turn on or off, thereby performing PWM modulation on the coil current of the conductive coil 21.

[0071] like Figure 5 As shown, in some embodiments of this application, the voltage sampling unit 310 may include a first voltage divider resistor string, a second capacitor C2, and a first TVS diode TVS1; the first end of the first voltage divider resistor string is connected to the DC bus and connected to the DC voltage DC_BUS; the voltage divider node N1 of the first voltage divider resistor string is connected to the first end of the second capacitor C2, the first end of the first TVS diode TVS1, and the sampling input terminal of the main control unit 320 to output the sampling voltage VF; the second end of the first voltage divider resistor string, the second end of the second capacitor C2, and the second end of the first TVS diode TVS1 are grounded to GND.

[0072] In this embodiment, the first voltage divider resistor string includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a seventh resistor R7 connected in series. The third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, and the seventh resistor R7 are connected in series to divide the DC voltage DC_BUS. The voltage divided by the seventh resistor R7 is the sampling voltage VF supplied to the main control unit 320.

[0073] Please continue reading. Figure 4In some embodiments of this application, the control module 300 may further include a voltage conversion unit 340; the voltage conversion unit 340 may be connected to the linear step-down module 100, the mutual inductance power supply module 200 and the main control unit 320 respectively, and may be used to convert the first power supply voltage or the second power supply voltage into a working voltage and output it to the power supply terminal of the main control unit 320 to power the main control unit 320.

[0074] In this embodiment, the voltage conversion unit 340 can be implemented using any existing DC-DC converter. The voltage conversion unit 340 can convert the first supply voltage from the linear step-down module 100 or the second supply voltage from the mutual inductance power supply module 200 into a working voltage adapted to the main control unit 320 to power the main control unit 320.

[0075] like Figure 6 As shown, as an example, the main control unit 320 is implemented using an MCU chip U3, which operates at a voltage of +5V. The voltage conversion unit 340 can be implemented using a DC-DC converter U4, which converts the +12V voltage to a +5V voltage to supply the power supply terminal VDD of the MCU chip U3.

[0076] Please continue reading. Figure 6 The power switch 22 is implemented using a power switching transistor Q5, and the drive unit 330 is implemented using a drive chip U5. The drive chip U5 receives the modulation signal, i.e., the PWM signal, from the MCU chip U3, amplifies it, and outputs a control signal Ctrl to the gate of the power switching transistor Q5. By controlling the conduction and turn-off of the power switching transistor Q5, the current of the conductive coil 21 (J1) is PWM modulated.

[0077] Please continue reading. Figure 3 In some embodiments of this application, the control module 300 may further include a state sampling unit 350; the state sampling unit 350 is connected to the mutual inductance power supply module 200, the linear step-down module 100 and the main control unit 320 respectively, and can be used to generate a first state voltage based on the DC voltage and output it to the main control unit 320 when the mutual inductance power supply module 200 does not generate a turn-off signal, and to generate a second state voltage based on the turn-off signal and output it to the main control unit 320 when the mutual inductance power supply module 200 generates a turn-off signal.

[0078] In this embodiment, the state sampling unit 350 may include a thirteenth resistor R13 and a fourteenth resistor R14. The thirteenth resistor R13 is connected to the first terminal of the first switch Q1 and the control terminal of the third switch Q3, respectively. The connection node of the thirteenth resistor R13 and the fourteenth resistor R14 is connected to an input terminal of the main control unit 320, and outputs a state voltage VF1 to it. That is to say, the voltage obtained by the fourteenth resistor R14 is the state voltage VF1.

[0079] Specifically, when the linear buck module 100 is working normally, the thirteenth resistor R13 and the fourteenth resistor R14 are connected in series to divide the voltage. At this time, the output state voltage VF1 is the first state voltage, which is greater than the set voltage threshold. Therefore, the main control unit 320 receives the first state voltage, compares it with the preset voltage threshold, and determines that the first state voltage is greater than the voltage threshold, thereby determining that the linear buck module 100 is working normally.

[0080] When the mutual inductance power supply module 200 supplies power and outputs a shutdown signal, the linear buck module 100 stops working. At this time, the output state voltage VF1 is the second state voltage, which will be less than the voltage threshold. Therefore, the main control unit 320 receives the second state voltage, compares it with the set voltage threshold, and determines that the second state voltage is less than the voltage threshold, thereby determining that the linear buck module 100 stops working.

[0081] In this embodiment, the main control unit 320 determines the operating state of the linear buck module 100 by the voltage division value of the thirteenth resistor R13 and the fourteenth resistor R14, i.e., the state voltage VF1. When the linear buck module 100 stops working, the state voltage VF1 is lower than a voltage threshold, and at this time, it is determined that the linear buck module 100 has stopped working. When the linear buck module 100 is working normally, the state voltage VF1 is higher than the voltage threshold, and at this time, it is determined that the linear buck module 100 is working. It can be understood that this voltage threshold can be determined based on the voltage division of the thirteenth resistor R13 and the fourteenth resistor R14, and is not limited here.

[0082] like Figure 7 As shown, in some embodiments of this application, the power supply circuit 10 may further include an anti-interference rectifier module 400, which is connected to the DC bus and can be used to perform anti-interference and rectification processing on the input AC voltage to obtain a DC voltage output to the DC bus.

[0083] In this embodiment, the anti-interference rectifier module 400 can be implemented by sampling any existing EMI (Electromagnetic Interference) module. The anti-interference rectifier module 400 can perform anti-interference processing and rectification on the received AC voltage to obtain a DC voltage output to the DC bus.

[0084] The anti-interference rectifier module 400 can prevent the contactor's own circuit from being affected by external electromagnetic interference, and also prevent the noise generated by the contactor from interfering with surrounding equipment, ensuring that the contactor can stably control the switching action and will not malfunction due to interference.

[0085] Please see Figure 8 As an example, the anti-interference rectifier module 400 may include a varistor RY1, a thirteenth capacitor C13, a second current transformer L2, a fourteenth capacitor C14, and a second rectifier bridge BR2. The varistor RY1 is connected between the live wire and the neutral wire. When the input AC voltage suddenly spikes (such as from lightning strikes or power grid surges) and exceeds its trigger voltage, its resistance instantly becomes extremely small, acting like a wire to short-circuit the excessive AC voltage to the ground wire, thus preventing high voltage from damaging the precision components in the subsequent stages.

[0086] The thirteenth capacitor, C13, is connected between the live wire and the neutral wire. It can absorb high-frequency electromagnetic noise in the circuit and filter high-frequency interference in the live wire. The two coils of the second transformer, L2, are connected in series with the live wire and the neutral wire, respectively. When common-mode interference (noise carried by both the live wire and the neutral wire, such as current induced by external electromagnetic radiation) occurs in the circuit, the magnetic fields generated by the two coils will reinforce each other, thus hindering the interference and preventing it from passing through. The magnetic fields generated by the differential-mode current (current entering from the live wire and exiting from the neutral wire) during normal operation will cancel each other out and will not affect the normal power supply.

[0087] The fourteenth capacitor, C14, is connected between the live wire and the neutral wire. It can filter differential mode interference (noise between the live wire and the neutral wire, such as voltage fluctuations caused by internal switching actions) and absorb high-frequency pulses between the live wire and the neutral wire, making the output voltage more stable.

[0088] The second rectifier bridge BR2 converts the input AC voltage (e.g., 220V AC) into DC voltage. It also smooths out some AC-side interference and prevents DC-side noise from being conducted back to the AC side, providing a degree of isolation. The rectified DC voltage is then filtered by the twelfth capacitor C12, further reducing ripple and providing a stable DC voltage for subsequent circuits.

[0089] Based on the above embodiments, this application also provides a switching device, which may include a conductive coil and a device connected to the conductive coil, such as... Figures 1 to 8 The power supply circuit corresponds to any embodiment.

[0090] The switchgear can be a wide-voltage contactor, circuit breaker, or other electrical switch.

[0091] Since the switchgear includes the present application, as described in this application Figures 1 to 8 Corresponding to the power supply circuit in any embodiment, the present application can be implemented as described above. Figures 1 to 8 For all the beneficial effects that the power supply circuit can achieve in any embodiment, please refer to the preceding description, which will not be repeated here.

[0092] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Although this application has disclosed preferred embodiments as above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A power supply circuit, characterized in that, It includes a linear step-down module, a mutual inductor power supply module, and a control module; The linear step-down module is connected to the DC bus and is used to step down the DC voltage on the DC bus to obtain a first supply voltage, which is then output to the control module to power the control module. The control module is connected to the DC bus and the conductive coil connected to the DC bus, respectively, and is used to generate a control signal according to the DC voltage and output it to the conductive coil to adjust the coil current. The mutual inductance power supply module is connected to the DC bus, the linear step-down module, and the control module, respectively. It is used to generate an induced voltage based on the pulsating current on the DC bus when the control module adjusts the coil current, and to obtain a second power supply voltage based on the induced voltage and output it to the control module to power the control module. When the second power supply voltage reaches a preset voltage value, it generates a shutdown signal and outputs it to the linear step-down module to stop the linear step-down module from working.

2. The power supply circuit according to claim 1, characterized in that, The mutual inductance power supply module includes an induction unit, a rectifier output unit, and a voltage comparison unit; The sensing unit is connected to the DC bus and the rectifier output unit, and is used to generate the induced voltage based on the pulsating current on the DC bus and output it to the rectifier output unit. The rectifier output unit is connected to the control module and the voltage comparison unit respectively, and is used to rectify the induced voltage to obtain the second power supply voltage and output it to the control module and the voltage comparison unit. The voltage comparison unit is used to generate the shutdown signal and output it to the linear buck module when the second supply voltage reaches the preset voltage value.

3. The power supply circuit according to claim 2, characterized in that, The sensing unit includes a first current transformer, and the rectifier output unit includes a first rectifier bridge, a first capacitor, and a first diode. The primary winding of the first current transformer is connected to the DC bus, and the secondary winding of the first current transformer is connected to the third and fourth ends of the first rectifier bridge, respectively. The first end of the first rectifier bridge is connected to the first end of the first capacitor and the anode of the first diode, the cathode of the first diode is connected to the control module, and the second end of the first rectifier bridge and the second end of the first capacitor are grounded.

4. The power supply circuit according to claim 2, characterized in that, The voltage comparison unit includes a first Zener diode, a first resistor, and a first switching transistor; The cathode of the first Zener diode is connected to the rectifier output unit, the anode of the first Zener diode is connected to the first end of the first resistor and the control terminal of the first switch, the first end of the first switch is connected to the linear buck module, and the second end of the first resistor and the second end of the first switch are grounded.

5. The power supply circuit according to claim 1, characterized in that, The control module includes a voltage sampling unit, a main control unit, and a drive unit; The voltage sampling unit is connected to the DC bus and the main control unit respectively, and is used to sample the DC voltage and output the sampled voltage to the main control unit based on the DC voltage. The main control unit is connected to the drive unit and is used to generate a modulation signal based on the sampled voltage and output it to the drive unit. The driving unit is connected to a power switch connected in series with the conductive coil, and is used to generate a control signal based on the modulation signal and output it to the power switch, so as to regulate the coil current by controlling the switching state of the power switch.

6. The power supply circuit according to claim 5, characterized in that, The voltage sampling unit includes a first voltage divider resistor string, a second capacitor, and a first TVS diode; The first end of the first voltage divider resistor string is connected to the DC bus, the voltage divider node of the first voltage divider resistor string is connected to the first end of the second capacitor, the first end of the first TVS diode and the sampling input terminal of the main control unit, and the second end of the first voltage divider resistor string, the second end of the second capacitor and the second end of the first TVS diode are grounded.

7. The power supply circuit according to claim 5, characterized in that, The control module further includes a voltage conversion unit; the voltage conversion unit is connected to the linear step-down module, the mutual inductance power supply module and the main control unit respectively, and is used to convert the first power supply voltage or the second power supply voltage into a working voltage and output it to the power supply terminal of the main control unit to power the main control unit.

8. The power supply circuit according to claim 5, characterized in that, The control module also includes a status sampling unit; The state sampling unit is connected to the mutual inductance power supply module, the linear step-down module and the main control unit respectively, and is used to generate a first state voltage and output it to the main control unit according to the DC voltage when the mutual inductance power supply module does not generate the shutdown signal, and to generate a second state voltage and output it to the main control unit according to the shutdown signal when the mutual inductance power supply module generates the shutdown signal.

9. The power supply circuit according to claim 1, characterized in that, The power supply circuit also includes an anti-interference rectifier module, which is connected to the DC bus and is used to perform anti-interference and rectification processing on the input AC voltage to obtain the DC voltage output to the DC bus.

10. A switching device, characterized in that, It includes a conductive coil and a power supply circuit according to any one of claims 1 to 9.

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