DC contactor driving power supply based on super capacitor transient support

Abstract

The invention discloses a DC contactor driving power supply based on super capacitor transient support, a Buck-Boost circuit is adopted to stably output rated coil power supply voltage, a constant current output function is introduced through a current sampling circuit and a current loop of a double-closed-loop structure, constant current and constant voltage charging of a super capacitor is realized, compared with a resistor current limiting mode, the charging mode is more flexible, and the charging efficiency is improved. The circuit has a fast charging function, can reduce heating loss, and is small in size and low in cost; the super capacitor string performs constant current-constant voltage charging through the Buck-Boost circuit, and the control system controls the driving switch to supply power to the contactor coil. When the contactor acts, the control system controls the driving switch to be turned on, the high-density electric quantity stored in the super capacitor string is released, instantaneous large current is provided for the contactor coil, reliable action of the contactor is ensured, the contactor keeps that the electric quantity is provided by the Buck-Boost circuit after action, and the input power supply cost and the occupied volume are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of DC contactor driving, and in particular to a DC contactor driving power supply based on supercapacitor transient support. Background Art

[0002] As a switching electrical device, DC contactors have found widespread application in numerous fields due to their unique performance and advantages. In the new energy sector, electric vehicles, charging stations, and solar power systems all rely on the precise control of DC contactors. In industrial equipment, critical links such as power systems and energy storage systems rely on their stable operation. In the rail transit sector, DC contactors are also widely used in the electrical systems of high-speed vehicles such as high-speed trains and subways. Furthermore, DC contactors play an indispensable role in specialized equipment such as aerospace and medical devices.

[0003] In many high-voltage, high-current applications, DC contactors are typically designed with dual coils to ensure reliable current interruption while reducing coil holding power consumption and system temperature rise. This dual-coil power supply approach has unique characteristics: when the contactor operates, the coil requires a transient (tens of milliseconds) high starting current. Depending on the current level of the contactor's main contacts and the coil supply voltage, the coil starting current can range from several amperes to tens of amperes. However, once the contactor enters the holding state, its holding current is only 10% to 20% of the starting current.

[0004] Currently, there are two common solutions for powering the coils of these DC contactors: direct power supply from a switching power supply, and voltage reduction using a transformer followed by rectification. Both power supply methods present several challenges in practical applications. When the coil's starting current is high, a high-power switching power supply or transformer is often required to meet this transient current demand. However, once the contactor enters the steady-state holding phase, its current demand is minimal, resulting in extremely low power supply utilization, typically only 10% to 20%. Furthermore, the situation becomes even more complex when multiple contactors need to operate simultaneously. To meet the current demands of these contactors, multiple high-power switching power supplies or increased transformer power may be required. This not only significantly increases costs but also reduces size advantages, complicating equipment installation and layout.

[0005] More seriously, current mainstream power supplies have a significant drawback: due to their lack of energy storage, they may not be able to provide sufficient energy to maintain the contactor's hold during grid outages or low-voltage ride-through events. This can cause the contactor to malfunction, potentially leading to serious system problems and posing a significant threat to the stability and reliability of the entire electrical system. Therefore, addressing these issues with existing DC contactor coil power supply methods, improving power utilization, reducing costs and size, and enhancing system stability during grid anomalies has become a pressing technical challenge. Summary of the Invention

[0006] Based on the problems raised by the above background technology, the purpose of the present invention is to provide a DC contactor drive power supply based on supercapacitor transient support, which solves the problems of low power utilization, high cost, large size and inability to maintain the contactor state when the power grid is abnormal in the existing DC contactor dual-coil power supply method.

[0007] The present invention is achieved through the following technical solutions: The present invention provides a DC contactor driving power supply based on supercapacitor transient support, comprising: Buck-Boost circuit, current sampling circuit, control system, supercapacitor string, drive switch and contactor coil; The Buck-Boost circuit and the current sampling circuit form a current loop, and the current loop and the voltage loop of the Buck-Boost circuit itself form a double closed-loop structure, and the double closed-loop structure is used to charge the supercapacitor string with constant current and constant voltage; When the contactor needs to be activated, the control system controls the drive switch to open, so that the supercapacitor string releases the high-density electricity stored and provides instantaneous high current to the contactor coil.

[0008] In the above technical solution, the Buck-Boost circuit can stably output the rated coil supply voltage, regardless of whether the input power voltage is below or above the coil rating. This ensures sufficient coil startup voltage while preventing damage due to excessive voltage. Furthermore, a constant current output function is introduced through a current sampling circuit and a dual closed-loop current loop, enabling constant current and constant voltage charging of the supercapacitor. Compared to resistor-limited current, this charging method is more flexible, offers fast charging capabilities, and reduces heat loss. Furthermore, the circuit is compact and low-cost.

[0009] During operation, the supercapacitor string is charged at a constant current and constant voltage using a Buck-Boost circuit. The control system controls the driver switch to power the contactor coil. When the contactor actuates, the control system opens the driver switch, releasing the high-density charge stored in the supercapacitor string. This provides a high instantaneous current to the contactor coil, ensuring reliable contactor operation. After actuation, the Buck-Boost circuit maintains the contactor's charge.

[0010] The above technical solution allows the contactor coil starting power to be generated by the supercapacitor string, eliminating the need for a high-power input power supply. The input power only needs to meet the contactor holding current, thereby achieving a power utilization rate of 90% to 100%, reducing the input power cost and volume. In addition, the energy stored in the supercapacitor string can maintain the normal operation of the control system and drive switch during a short power outage or low voltage ride-through of the input power supply, ensuring that the contactor coil is powered and the contactor operates normally until the input power returns to normal, effectively avoiding system problems caused by short power outages or low voltage ride-through.

[0011] In an optional embodiment, the Buck-Boost circuit includes: a first module, a second module, a chip U1, a third module, a fourth module, a resistor R7, a resistor R6, a capacitor C10, a resistor R4, a resistor R5, a MOS tube Q1, a resistor R2, and a capacitor C8; The resistor R7 is connected in parallel with the capacitor C10 and in series with the resistor R6; the resistor R4 is connected in parallel between the resistor R3 and pin 5 of the chip U1; the resistor R5 is connected in parallel between the resistor R3 and pin 4 of the chip U1; The MOS tube Q1 and the resistor R2 are connected in series to the pin 19 of the chip U1, and the capacitor C8 is connected to the pin 18 of the chip U1; The first module includes capacitors C1, C2, C3, C4, and C5 connected in parallel, and the first module is connected to pin 1 of the chip U1 via capacitor R3; The second module includes a resistor R1, a capacitor C6, and a capacitor C7 connected in parallel, and the second module is connected to pin 17 of the chip U1; The third module includes a resistor R16, a resistor R17, a resistor R18, a resistor R14, and a resistor R15 connected in series, and a capacitor C20 connected in parallel with the resistor R18 and the resistor R14; the third module is connected to pin 1 of the chip U1 through capacitor C9, connected to pin 7 of the chip U1 through capacitor C16, connected to pin 5 of the chip U1 through capacitor C11, and connected to pin 3 of the chip U1 through resistor R8; The fourth module includes a diode D3, a diode D1, a resistor R9, an inductor L1, a MOS transistor Q2, and a capacitor C17, a resistor R13, a resistor R12, and a resistor R10 connected in sequence to form a ring; wherein the ring is connected to the diode D3 and the diode D1, and is connected to pin 13 of the chip U1; the diode D3 and the diode D1 are connected through the inductor L1, the MOS transistor Q2 and the resistor R9 are connected in series and then connected to pin 15 of the chip U1; the inductor L1 is connected to pin 20 of the chip U1.

[0012] In an optional embodiment, the model of the chip U1 is LM5118MHXNOPB.

[0013] In an optional embodiment, the diode D1 and the diode D3 are both of model SBDB30100CT.

[0014] In an optional embodiment, the current sampling circuit includes: an amplifier U15A, an amplifier U15B, a diode D21, a resistor R129, a resistor R124, a resistor R121, a resistor R125, a resistor R134, a resistor R140, a resistor R131, and a resistor R127; The resistor R140 and the resistor R134 are connected in series and then connected to the non-inverting input terminal of the amplifier U15B. The resistor R131 is connected to the positive input terminal of the amplifier U15B. The resistor R121 and the resistor R125 are connected in series and then connected in parallel between the inverting input terminal and the output terminal of the amplifier U15B. The resistor R127 is connected to the inverting input terminal of the amplifier U15B. The output end of the amplifier U15B is connected to the non-inverting input end of the amplifier U15A, the output end of the amplifier U15A is connected to the diode D21, the resistor R124 is connected in parallel between the inverting input end of the amplifier U15A and the diode D21; the diode D21 is connected to the resistor R129.

[0015] In an optional embodiment, the supercapacitor string includes: a first capacitor group, a second capacitor group, a third capacitor group, a fourth capacitor group, a fifth capacitor group, a sixth capacitor group, a seventh capacitor group, an eighth capacitor group, a ninth capacitor group, a tenth capacitor group, an eleventh capacitor group and a twelfth capacitor group connected in series in sequence; wherein each capacitor group includes a capacitor and a resistor, and the capacitor is connected in parallel with the resistor.

[0016] In an optional embodiment, the driving switch includes: a switch JK1, a diode D7, a diode D6, an inductor L6, a MOS transistor Q3, a resistor R25, a resistor R22, a MOS transistor Q6, a resistor R113, and a resistor R21; The diode D7 is connected to pins 7 and 8 of the switch JK1; the diode D6 is connected in parallel between pins 1 and 2 of the switch JK1; the inductor L1 is connected to pin 2 of the switch JK1; the capacitor R25 is connected in parallel between the base and emitter of the MOS transistor Q3; the collector of the MOS transistor Q3 is connected to pin 1 of the switch JK1; the resistor R22 is connected to the collector of the MOS transistor Q6; the resistor R113 is connected in parallel between the base and emitter of the MOS transistor Q6; and the resistor R21 is connected to the base of the MOS transistor Q6. In an optional embodiment, the switch JK1 adopts a model of HF115F / 005-1HS3AF.

[0017] In an optional embodiment, the DC contactor drive power supply further includes a rectifier circuit, which is used to receive an external power supply, rectify the external power supply, and input the rectified external power supply into the Buck-Boost circuit.

[0018] In an optional embodiment, the rectifier circuit includes: a diode D15, a diode 16, a diode D17, a diode D18, a diode D19, a diode D20 and a polarized capacitor E7; The diode D15 is connected in series with the diode D18; the diode D16 is connected in series with the diode D19; the diode D17 is connected in series with the diode D20; The diodes D15 and D18 connected in series are connected in series, and the diodes D16 and D19 connected in series, and the diodes D17 and D20 connected in series are connected in parallel; The polarized capacitor E7 is connected in parallel with the diode D17 and the diode D20 connected in series.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. Introducing supercapacitor strings, using the high power density characteristics of supercapacitors to provide instantaneous current for DC contactor startup, overcoming the low power utilization problem of ordinary power direct drive. Compared with lithium batteries and nickel-metal hydride batteries, the charging and discharging rate is slow and the cycle life is short; 2. By utilizing the energy storage characteristics of supercapacitors, when the input power is temporarily cut off, the control system and contactor can be kept working normally, thus avoiding system downtime. 3. A Buck-Boost circuit is incorporated, and Buck-Boost's constant current charging technology is used to adapt to wide voltage input conditions to cope with complex grid fluctuations. A current loop is introduced on the basis of the Buck-Boost circuit to realize constant current and constant voltage charging of supercapacitors, achieving low-cost fast charging and excellent thermal management. It can be used in on-board supercapacitor module products. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the examples. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort. In the drawings: Figure 1 A schematic structural diagram of a DC contactor drive power supply based on supercapacitor transient support provided in Example 1 of the present invention; Figure 2 This is a circuit diagram of a DC contactor drive power supply based on supercapacitor transient support provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0022] Embodiment 1 of the present invention provides a DC contactor driving power supply based on supercapacitor transient support, such as Figure 1 As shown, the DC contactor drive power supply based on supercapacitor transient support includes: Buck-Boost circuit, current sampling circuit, control system, supercapacitor string, drive switch and contactor coil; The Buck-Boost circuit and the current sampling circuit form a current loop, and the current loop and the voltage loop of the Buck-Boost circuit itself form a double closed-loop structure, and the double closed-loop structure is used to charge the supercapacitor string with constant current and constant voltage; When the contactor needs to be activated, the control system controls the drive switch to open, so that the supercapacitor string releases the high-density electricity stored and provides instantaneous high current to the contactor coil.

[0023] It should be noted that the existing dual-coil power supply method of DC contactor has the problems of low power utilization, high cost, large size and inability to maintain the contactor state when the power grid is abnormal. A supercapacitor string is added to the DC contactor drive power supply. In scenarios where DC loads such as relays and DC circuit breakers require transient large currents, the high power density characteristics of supercapacitors are used to provide instantaneous current for the start-up of the DC contactor, overcoming the low power utilization problem of ordinary direct-drive power supply. Compared with lithium batteries and nickel-metal hydride batteries, the charging and discharging rate is slow and the cycle life is low.

[0024] At the same time, since supercapacitors have energy storage characteristics, introducing supercapacitor strings in the DC contactor drive power supply can utilize their energy storage characteristics to maintain the normal operation of the control system and contactor when the input power is temporarily disconnected, thus avoiding system downtime.

[0025] In addition, this DC contactor driver power supply introduces a Buck-Boost circuit, utilizing Buck-Boost's constant current charging technology to cope with input power fluctuations. The current loop realizes constant current and constant voltage charging of the supercapacitor, achieving low-cost fast charging and excellent thermal management, and can be used in onboard supercapacitor module products.

[0026] Specifically, the Buck-Boost circuit can stably output the rated coil supply voltage, regardless of whether the input power voltage is below or above the coil's rated value. This ensures sufficient coil startup voltage while preventing damage from excessive voltage. Furthermore, a constant current output function is introduced through a current sampling circuit and a dual-closed-loop current loop, enabling constant current and constant voltage charging of supercapacitors. Compared to resistor-limited current, this charging method is more flexible, offers fast charging capabilities, and reduces heat loss, while also being compact and cost-effective.

[0027] During operation, the supercapacitor string is charged at a constant current and voltage via a Buck-Boost circuit, while the control system controls the driver switch to power the contactor coil. When the contactor actuates, the control system controls the driver switch to open, releasing the high-density charge stored in the supercapacitor string and providing a high instantaneous current to the contactor coil, ensuring reliable contactor operation. After actuation, the Buck-Boost circuit maintains the contactor's charge. Constant current and constant voltage charging eliminates the need for a dedicated chip with current feedback; a standard DC-DC controller can achieve constant current charging. This provides a wider range of control chip options and reduces limitations.

[0028] This technical solution allows the contactor coil's starting power to be generated by a supercapacitor string, eliminating the need for a high-power input power supply. The input power only needs to meet the contactor's holding current, achieving a 90% to 100% power utilization rate and reducing input power costs and footprint. Furthermore, the energy stored in the supercapacitor string can maintain the normal operation of the control system and drive switch during a short power outage or low voltage ride-through, ensuring that the contactor coil remains powered and maintains normal contactor operation until the input power returns to normal, effectively avoiding system problems caused by short power outages or low voltage ride-through.

[0029] In an optional embodiment, the Buck-Boost circuit includes: a first module, a second module, a chip U1, a third module, a fourth module, a resistor R7, a resistor R6, a capacitor C10, a resistor R4, a resistor R5, a MOS tube Q1, a resistor R2, and a capacitor C8; The resistor R7 is connected in parallel with the capacitor C10 and in series with the resistor R6; the resistor R4 is connected in parallel between the resistor R3 and pin 5 of the chip U1; the resistor R5 is connected in parallel between the resistor R3 and pin 4 of the chip U1; The MOS tube Q1 and the resistor R2 are connected in series to the pin 19 of the chip U1, and the capacitor C8 is connected to the pin 18 of the chip U1; The first module includes capacitors C1, C2, C3, C4, and C5 connected in parallel, and the first module is connected to pin 1 of the chip U1 via capacitor R3; The second module includes a resistor R1, a capacitor C6, and a capacitor C7 connected in parallel, and the second module is connected to pin 17 of the chip U1; The third module includes a resistor R16, a resistor R17, a resistor R18, a resistor R14, and a resistor R15 connected in series, and a capacitor C20 connected in parallel with the resistor R18 and the resistor R14; the third module is connected to pin 1 of the chip U1 through capacitor C9, connected to pin 7 of the chip U1 through capacitor C16, connected to pin 5 of the chip U1 through capacitor C11, and connected to pin 3 of the chip U1 through resistor R8; The fourth module includes a diode D3, a diode D1, a resistor R9, an inductor L1, a MOS transistor Q2, and a capacitor C17, a resistor R13, a resistor R12, and a resistor R10 connected in sequence to form a ring; wherein the ring is connected to the diode D3 and the diode D1, and is connected to pin 13 of the chip U1; the diode D3 and the diode D1 are connected through the inductor L1, the MOS transistor Q2 and the resistor R9 are connected in series and then connected to pin 15 of the chip U1; the inductor L1 is connected to pin 20 of the chip U1.

[0030] The output end of the Buck-Boost circuit is further connected in parallel with a polarized capacitor E1.

[0031] In an optional embodiment, the model of the chip U1 is LM5118MHXNOPB.

[0032] In an optional embodiment, the diode D1 and the diode D3 are both of model SBDB30100CT.

[0033] In an optional embodiment, the current sampling circuit includes: an amplifier U15A, an amplifier U15B, a diode D21, a resistor R129, a resistor R124, a resistor R121, a resistor R125, a resistor R134, a resistor R140, a resistor R131, and a resistor R127; The resistor R140 and the resistor R134 are connected in series and then connected to the non-inverting input terminal of the amplifier U15B. The resistor R131 is connected to the positive input terminal of the amplifier U15B. The resistor R121 and the resistor R125 are connected in series and then connected in parallel between the inverting input terminal and the output terminal of the amplifier U15B. The resistor R127 is connected to the inverting input terminal of the amplifier U15B. The output end of the amplifier U15B is connected to the non-inverting input end of the amplifier U15A, the output end of the amplifier U15A is connected to the diode D21, the resistor R124 is connected in parallel between the inverting input end of the amplifier U15A and the diode D21; the diode D21 is connected to the resistor R129.

[0034] In an optional embodiment, the supercapacitor string includes: a first capacitor group, a second capacitor group, a third capacitor group, a fourth capacitor group, a fifth capacitor group, a sixth capacitor group, a seventh capacitor group, an eighth capacitor group, a ninth capacitor group, a tenth capacitor group, an eleventh capacitor group and a twelfth capacitor group connected in series in sequence; wherein each capacitor group includes a capacitor and a resistor, and the capacitor is connected in parallel with the resistor.

[0035] It should be noted that the negative end of the supercapacitor string is connected to the Buck-Boost circuit through the current-sense resistor R88 and is directly connected to the current sampling circuit.

[0036] The input and output of the supercapacitor string are connected in parallel with the output of the Buck-Boost circuit, and there is no undervoltage selection switch. When the input power supply is powered, the Buck-Boost circuit provides energy to the load. When the input power supply is powered off, the supercapacitor is automatically switched to provide energy to the load to maintain normal operation of the system.

[0037] In an optional embodiment, the driving switch includes: a switch JK1, a diode D7, a diode D6, an inductor L6, a MOS transistor Q3, a resistor R25, a resistor R22, a MOS transistor Q6, a resistor R113, and a resistor R21; The diode D7 is connected to pins 7 and 8 of the switch JK1; the diode D6 is connected in parallel between pins 1 and 2 of the switch JK1; the inductor L1 is connected to pin 2 of the switch JK1; the capacitor R25 is connected in parallel between the base and emitter of the MOS transistor Q3; the collector of the MOS transistor Q3 is connected to pin 1 of the switch JK1; the resistor R22 is connected to the collector of the MOS transistor Q6; the resistor R113 is connected in parallel between the base and emitter of the MOS transistor Q6; and the resistor R21 is connected to the base of the MOS transistor Q6. In an optional embodiment, the switch JK1 adopts a model of HF115F / 005-1HS3AF.

[0038] In an optional embodiment, the DC contactor drive power supply further includes a rectifier circuit, which is used to receive an external power supply, rectify the external power supply, and input the rectified external power supply into the Buck-Boost circuit.

[0039] In an optional embodiment, the rectifier circuit includes: a diode D15, a diode 16, a diode D17, a diode D18, a diode D19, a diode D20 and a polarized capacitor E7; The diode D15 is connected in series with the diode D18; the diode D16 is connected in series with the diode D19; the diode D17 is connected in series with the diode D20; The diodes D15 and D18 connected in series are connected in series, and the diodes D16 and D19 connected in series, and the diodes D17 and D20 connected in series are connected in parallel; The polarized capacitor E7 is connected in parallel with the diode D17 and the diode D20 connected in series.

[0040] It should be noted that an external power supply compatible with both AC and DC is input into the rectifier circuit. The rectifier circuit is compatible with both DC current input from the transformer and AC current input from the switching power supply, thus realizing the function of both AC and DC power supply, making the application of DC contactor drive power supply more flexible.

[0041] In this embodiment, the DC contactor driver power supply is applied to a DC contactor power load with a coil specification of 24V DC, a starting current of 13.5A, and a holding current of 0.45A. The external power supply is first input into a three-phase bridge rectifier circuit, which rectifies the output voltage to 15V to 50V DC. This voltage is then input into a buck-boost circuit, which undergoes DC-DC conversion to output 24V DC. A current-sense resistor is placed at the negative output terminal of the buck-boost circuit. The current sampling circuit uses an op amp to sample and amplify the current from the current-sense resistor, sending the sampled voltage to the feedback terminal of the power supply chip. The op amp parameters are set to achieve a constant current of 1A charging of the supercapacitor string. The buck-boost circuit output powers the control system. When the contactor is activated, the control system MCU commands the driver switch intermediate relay to close, releasing the supercapacitor string charge to the contactor coil, causing it to receive a transient high current of 13.5A to complete the closing. After the contactor coil reaches steady state, the current remains at 0.45A. The buck-boost circuit's constant current capability of 1A ensures normal contactor closing. When the power input is instantly cut off, the energy stored in the supercapacitor string can maintain the normal operation of the control system and drive switch, ensuring that the contactor coil is not disconnected and maintaining the normal operation of the contactor until the input power is restored.

[0042] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A DC contactor drive power supply based on supercapacitor transient support, characterized in that: Buck-Boost circuit, current sampling circuit, control system, supercapacitor string, drive switch and contactor coil; The Buck-Boost circuit and the current sampling circuit form a current loop, and the current loop and the voltage loop of the Buck-Boost circuit itself form a double closed-loop structure, and the double closed-loop structure is used to charge the supercapacitor string with constant current and constant voltage; When the contactor needs to be activated, the control system controls the drive switch to open, so that the supercapacitor string releases the high-density electricity stored and provides instantaneous high current to the contactor coil.

2. The DC contactor driving power supply based on supercapacitor transient support according to claim 1, characterized in that: The Buck-Boost circuit includes: a first module, a second module, a chip U1, a third module, a fourth module, a resistor R7, a resistor R6, a capacitor C10, a resistor R4, a resistor R5, a MOS tube Q1, a resistor R2, and a capacitor C8; The resistor R7 is connected in parallel with the capacitor C10 and in series with the resistor R6; the resistor R4 is connected in parallel between the resistor R3 and pin 5 of the chip U1; the resistor R5 is connected in parallel between the resistor R3 and pin 4 of the chip U1; The MOS tube Q1 and the resistor R2 are connected in series to the pin 19 of the chip U1, and the capacitor C8 is connected to the pin 18 of the chip U1; The first module includes capacitors C1, C2, C3, C4, and C5 connected in parallel, and the first module is connected to pin 1 of the chip U1 via capacitor R3; The second module includes a resistor R1, a capacitor C6, and a capacitor C7 connected in parallel, and the second module is connected to pin 17 of the chip U1; The third module includes a resistor R16, a resistor R17, a resistor R18, a resistor R14, and a resistor R15 connected in series, and a capacitor C20 connected in parallel with the resistor R18 and the resistor R14; the third module is connected to pin 1 of the chip U1 through capacitor C9, connected to pin 7 of the chip U1 through capacitor C16, connected to pin 5 of the chip U1 through capacitor C11, and connected to pin 3 of the chip U1 through resistor R8; The fourth module includes a diode D3, a diode D1, a resistor R9, an inductor L1, a MOS transistor Q2, and a capacitor C17, a resistor R13, a resistor R12, and a resistor R10 connected in sequence to form a ring; wherein the ring is connected to the diode D3 and the diode D1, and is connected to pin 13 of the chip U1; the diode D3 and the diode D1 are connected through the inductor L1, the MOS transistor Q2 and the resistor R9 are connected in series and then connected to pin 15 of the chip U1; the inductor L1 is connected to pin 20 of the chip U1.

3. The DC contactor driving power supply based on supercapacitor transient support according to claim 2, characterized in that: The model of the chip U1 is LM5118MHXNOPB.

4. The DC contactor driving power supply based on supercapacitor transient support according to claim 2, characterized in that: The diode D1 and the diode D3 are both of model SBDB30100CT.

5. The DC contactor driving power supply based on supercapacitor transient support according to claim 1, characterized in that: The current sampling circuit includes: an amplifier U15A, an amplifier U15B, a diode D21, a resistor R129, a resistor R124, a resistor R121, a resistor R125, a resistor R134, a resistor R140, a resistor R131, and a resistor R127; The resistor R140 and the resistor R134 are connected in series and then connected to the non-inverting input terminal of the amplifier U15B. The resistor R131 is connected to the positive input terminal of the amplifier U15B. The resistor R121 and the resistor R125 are connected in series and then connected in parallel between the inverting input terminal and the output terminal of the amplifier U15B. The resistor R127 is connected to the inverting input terminal of the amplifier U15B. The output end of the amplifier U15B is connected to the non-inverting input end of the amplifier U15A, the output end of the amplifier U15A is connected to the diode D21, the resistor R124 is connected in parallel between the inverting input end of the amplifier U15A and the diode D21; the diode D21 is connected to the resistor R129.

6. The DC contactor driving power supply based on supercapacitor transient support according to claim 1, characterized in that: The supercapacitor string includes: a first capacitor group, a second capacitor group, a third capacitor group, a fourth capacitor group, a fifth capacitor group, a sixth capacitor group, a seventh capacitor group, an eighth capacitor group, a ninth capacitor group, a tenth capacitor group, an eleventh capacitor group and a twelfth capacitor group connected in series in sequence; wherein each capacitor group includes a capacitor and a resistor, and the capacitor is connected in parallel with the resistor.

7. The DC contactor driving power supply based on supercapacitor transient support according to claim 1, characterized in that: The driving switch includes: switch JK1, diode D7, diode D6, inductor L6, MOS transistor Q3, resistor R25, resistor R22, MOS transistor Q6, resistor R113, and resistor R21; The diode D7 is connected to pins 7 and 8 of the switch JK1; the diode D6 is connected in parallel between pins 1 and 2 of the switch JK1; the inductor L1 is connected to pin 2 of the switch JK1; the capacitor R25 is connected in parallel between the base and emitter of the MOS transistor Q3; the collector of the MOS transistor Q3 is connected to pin 1 of the switch JK1; the resistor R22 is connected to the collector of the MOS transistor Q6; the resistor R113 is connected in parallel between the base and emitter of the MOS transistor Q6; and the resistor R21 is connected to the base of the MOS transistor Q6.

8. The DC contactor driving power supply based on supercapacitor transient support according to claim 7, characterized in that: The switch JK1 adopts the model HF115F / 005-1HS3AF.

9. The DC contactor driving power supply based on supercapacitor transient support according to claim 1, characterized in that: The DC contactor driving power supply further includes a rectifier circuit, which is used to receive an external power supply, rectify the external power supply, and input the rectified external power supply into the Buck-Boost circuit.

10. The DC contactor driving power supply based on supercapacitor transient support according to claim 9, characterized in that: The rectifier circuit includes: a diode D15, a diode 16, a diode D17, a diode D18, a diode D19, a diode D20 and a polarity capacitor E7; The diode D15 is connected in series with the diode D18; the diode D16 is connected in series with the diode D19; the diode D17 is connected in series with the diode D20; The diodes D15 and D18 connected in series are connected in series, and the diodes D16 and D19 connected in series, and the diodes D17 and D20 connected in series are connected in parallel; The polarized capacitor E7 is connected in parallel with the diode D17 and the diode D20 connected in series.

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