Three-single-phase in-line permanent magnetic mechanism vacuum circuit breaker with hand-closing function

Abstract

The invention provides a three-single-phase in-line permanent magnetic mechanism vacuum circuit breaker with a manual closing function, and relates to the technical field of electrical equipment control. According to the application, the first-stage voltage stabilizing circuit is arranged to carry out rectification and first-time voltage stabilizing processing on the input alternating current power supply voltage, the first direct current voltage is output, and then the second-stage voltage stabilizing circuit is used to carry out second-time voltage stabilizing processing on the first direct current voltage to obtain a more stable second direct current voltage; and then the voltage conversion circuit boosts the second direct-current voltage to a required third direct-current voltage, the capacitor module is charged under the protection of the capacitor charging protection circuit, and finally, the driving circuit accurately controls the switching-on or switching-off action of the circuit breaker according to the voltage state of the capacitor module. The series connection design of multi-stage voltage stabilization and protection can ensure the stability of each stage of voltage, thereby improving the reliability of the circuit breaker during manual closing operation.

Description

Technical Field

[0001] The present application relates to the technical field of electrical equipment control, and particularly relates to a three-phase in-line permanent magnet mechanism vacuum circuit breaker with a manual closing function. Background Art

[0002] The three-phase in-line permanent magnet mechanism vacuum circuit breaker is an important switching device applied to medium-voltage distribution overhead lines. This circuit breaker is driven by three independent permanent magnet mechanisms and has the characteristics of fast breaking speed, long service life, and maintenance-free. In the power system, this type of circuit breaker is mainly used for the control and protection of the power system, especially playing an important role in scenarios such as new energy power generation grid connection and frequent switching of industrial electricity loads.

[0003] Currently, during the operation of the power system, when a fault occurs in the system and the circuit breaker trips, the operating personnel need to promptly troubleshoot the fault and restore power supply. In some remote areas or under adverse weather conditions, remote control closing may not be achievable due to communication interruption or other reasons. Existing three-permanent magnet mechanism circuit breakers only support manual tripping operations and do not have a manual closing function, which results in the inability to promptly restore power supply in special situations such as communication interruption. Although there are circuit breakers using a single permanent magnet / spring dual mechanism on the market that can achieve manual closing, these circuit breakers not only have a complex structure but also perform poorly in terms of the short-circuit fault breaking time (generally exceeding 10 ms), resulting in poor reliability of the circuit breaker in scenarios with high requirements for equipment stability such as new energy grid connection points. Summary of the Invention

[0004] The present application provides a three-phase in-line permanent magnet mechanism vacuum circuit breaker with a manual closing function, which can ensure the stability of voltages at all levels, thereby improving the reliability of the circuit breaker during manual closing operations.

[0005] The present application provides a three-phase in-line permanent magnet mechanism vacuum circuit breaker with a manual closing function. The circuit breaker includes a first-level voltage stabilization circuit, a second-level voltage stabilization circuit, a voltage conversion circuit, a capacitor charging protection circuit, and a driving circuit. The first-level voltage stabilization circuit, the second-level voltage stabilization circuit, the voltage conversion circuit, the capacitor charging protection circuit, and the driving circuit are connected in series in sequence, where: The first-level voltage stabilization circuit is used to rectify and perform the first-level voltage stabilization processing on the input AC power supply voltage, and output a first DC voltage; The second-level voltage stabilization circuit is used to perform the second-level voltage stabilization processing on the first DC voltage to obtain a second DC voltage; The voltage conversion circuit is used to boost the second DC voltage to a third DC voltage; The capacitor charging protection circuit is used to protect the capacitor module of the circuit breaker during charging; The driving circuit is used to drive the circuit breaker to complete the closing operation according to the voltage state of the capacitor module.

[0006] By adopting the above technical solution, a primary voltage stabilizing circuit is set to rectify and perform the first voltage stabilization process on the input AC power supply voltage, and output a first DC voltage. Then, a secondary voltage stabilizing circuit performs the second voltage stabilization process on the first DC voltage to obtain a more stable second DC voltage. Then, a voltage conversion circuit boosts the second DC voltage to the required third DC voltage, and charges the capacitor module under the protection of the capacitor charging protection circuit. Finally, the driving circuit accurately controls the closing or opening action of the circuit breaker according to the voltage state of the capacitor module. This series design of multi-stage voltage stabilization and protection not only ensures the stability of each stage of voltage, but also avoids possible damage to the capacitor module during the charging process through a dedicated protection circuit. At the same time, the driving circuit can perform intelligent control according to the actual voltage state of the capacitor module, thereby effectively improving the reliability of the circuit breaker during manual closing operation.

[0007] Optionally, the primary voltage stabilizing circuit includes a power transformer, a bridge rectifier, and a first voltage stabilizing unit, where: The primary coil of the power transformer is connected to the power supply, and the secondary coil of the power transformer is connected to the input end of the bridge rectifier; The positive output of the bridge rectifier is connected to the input end of the first voltage stabilizing unit, and the negative output of the bridge rectifier is grounded; The output end of the first voltage stabilizing unit is connected to the secondary voltage stabilizing circuit.

[0008] By adopting the above technical solution, the AC power supply input by the power transformer is stepped down, and the stepped-down AC voltage is input to the bridge rectifier for rectification to convert the alternating current into a pulsating direct current. The rectified voltage is subjected to voltage stabilization processing by the first voltage stabilizing unit, and a stable DC voltage is output to the secondary voltage stabilizing circuit. The step-down function of the power transformer can control the system working voltage within a suitable range. The bridge rectifier adopts a full-wave rectification method to improve the rectification efficiency and reduce the ripple. The voltage stabilization function of the first voltage stabilizing unit further filters out the ripple and provides a stable DC output.

[0009] Optionally, the first voltage stabilizing unit includes a voltage regulator, a first capacitor, a second capacitor, a first diode, a second diode, a first resistor, a second resistor, and a load resistor. The second resistor is a variable resistor, where: The first end of the voltage regulator is grounded through the second capacitor; The third end of the voltage regulator is grounded through the first capacitor. The third end of the voltage regulator serves as the input end of the first voltage stabilizing unit and is connected to the positive output of the bridge rectifier; The first end of the first resistor is connected to the second end of the voltage regulator, the second end of the first resistor is connected to the first end of the voltage regulator, and the second end of the first resistor is grounded through the second resistor; The positive electrode of the second diode is connected to the second end of the first resistor, the negative electrode of the second diode is connected to the positive electrode of the first diode, and the negative electrode of the first diode is connected to the third end of the voltage regulator; The first end of the load resistor is connected to the first end of the first resistor, the second end of the load resistor is grounded, and the first end of the load resistor serves as the output end of the first voltage regulation unit and is connected to the secondary voltage regulation circuit.

[0010] By adopting the above technical solution, the pulsating DC voltage output by the bridge rectifier is first input through the third end of the voltage regulator, and the input voltage is filtered by the first capacitor to reduce the ripple of the input voltage. The first end of the voltage regulator is grounded through the second capacitor to form a stable reference potential. The first resistor and the second resistor form a voltage dividing network, where the second resistor is a variable resistor and the output voltage can be adjusted according to actual requirements. The series configuration of the first diode and the second diode forms a protection circuit to prevent the reverse current from damaging the voltage regulator when the input voltage is abnormal. The load resistor is connected to the first end of the first resistor and grounded, which can limit the output current while providing a stable output voltage to avoid overload. This circuit structure enables the voltage regulation unit to convert the input pulsating DC voltage into a stable DC voltage and output it to the secondary voltage regulation circuit, while having the characteristics of overvoltage protection and adjustable output, improving the reliability and adaptability of the primary voltage regulation circuit.

[0011] Optionally, the primary voltage regulation circuit further includes a protection resistor, where: The protection resistor is respectively connected to the positive pole of the secondary coil of the power transformer and the input positive pole of the bridge rectifier.

[0012] By adopting the above technical solution, when the output voltage of the power transformer has an instantaneous overvoltage or an impact current is generated at the moment when the bridge rectifier starts, the protection resistor can consume the excess energy and limit the sudden change rate of the current, thereby protecting the bridge rectifier from transient voltage and surge current damage, and at the same time reducing the load impact on the power transformer.

[0013] Optionally, the secondary voltage regulation circuit includes a third capacitor, a fourth capacitor, a fifth capacitor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a third diode, a first transistor, a second transistor, and a third transistor, and the seventh resistor is a variable resistor, where: The input end of the secondary voltage regulation circuit is grounded through the third capacitor; The input terminals of the secondary voltage stabilizing circuit are respectively connected to the collector of the second transistor and the collector of the third transistor. The base of the third transistor is grounded through the fourth capacitor, and the emitter of the third transistor is connected to the base of the second transistor; The output terminal of the primary voltage stabilizing circuit is connected to the emitter of the first transistor through the third resistor, and the collector of the first transistor is connected to the emitter of the second transistor through the fourth resistor; The negative electrode of the third diode is connected to the collector of the first transistor, and the positive electrode of the third diode is grounded; The emitter of the second transistor is grounded through the series connection of the fifth resistor, the seventh resistor, and the sixth resistor. The base of the first transistor is connected to the sliding end of the seventh resistor; The positive electrode of the fifth capacitor is connected to the emitter of the second transistor, the negative electrode of the fifth capacitor is grounded, and the positive electrode of the fifth capacitor serves as the output terminal of the secondary voltage stabilizing circuit and is connected to the capacitor charging protection circuit.

[0014] By adopting the above technical solution, a three-stage transistor amplifier structure is adopted. The input voltage is preliminarily filtered through the third capacitor. The third transistor and the second transistor form a Darlington amplifier circuit to provide high-gain amplification. At the same time, the fourth capacitor stabilizes the base voltage of the third transistor. The first transistor is the main adjustment element, and its base voltage is controlled by the sliding end of the seventh variable resistor. By adjusting the seventh resistor, precise adjustment of the output voltage can be achieved. The third diode grounded constitutes a clamping protection to prevent the collector voltage of the first transistor from being too high. The voltage dividing network composed of the fifth resistor, the seventh resistor, and the sixth resistor provides a suitable bias voltage for the transistor, and the fifth capacitor finally filters the voltage at the output terminal. This structural design of multi-stage amplification and precise adjustment enables the secondary voltage stabilizing circuit to further stabilize the voltage output by the primary voltage stabilizing circuit, has higher voltage stabilizing accuracy and stronger anti-interference ability, and provides a stable and reliable DC voltage input for the subsequent capacitor charging protection circuit.

[0015] Optionally, the third diode is a Zener diode.

[0016] By adopting the above technical solution, when the collector voltage of the first transistor exceeds the breakdown voltage of the Zener diode, the Zener diode will conduct and clamp at its breakdown voltage value. This characteristic can not only provide overvoltage protection for the first transistor, but also use the constant voltage characteristic of the Zener diode to provide a stable reference voltage for the secondary voltage stabilizing circuit, improving the voltage stabilizing accuracy and reliability of the secondary voltage stabilizing circuit.

[0017] Optionally, the first transistor, the second transistor, and the third transistor are all NPN-type triodes.

[0018] By adopting the above technical solution, the common-emitter connection mode of the second transistor and the third transistor provides a large current amplification factor, while the first transistor provides linear regulation ability. The collaborative work of the three NPN-type triodes simplifies the bias design of the circuit and improves the reliability of the secondary voltage regulation circuit.

[0019] Optionally, the capacitor charging protection circuit includes an eighth resistor, a ninth resistor, a fourth transistor, a fourth diode, and a load output resistor, where: The positive input of the capacitor charging protection circuit is connected to the gate of the fourth transistor through the eighth resistor, and the drain and source of the fourth transistor are grounded; The positive electrode of the fourth diode is grounded, and the negative electrode of the fourth diode is connected to the gate of the fourth transistor; One end of the ninth resistor is connected to the gate of the fourth transistor, and the other end of the ninth resistor is grounded; The positive output of the capacitor charging protection circuit is grounded through the load output resistor.

[0020] By adopting the above technical solution, the input current is limited by the eighth resistor to provide a suitable driving voltage for the gate of the fourth transistor. The cooperation of the fourth diode and the ninth resistor constitutes a gate protection network to prevent the gate voltage from being too high and damaging the fourth transistor. When the input voltage rises, the fourth transistor gradually conducts, and the charging current is shunted through the low-impedance channel between its drain and source. At the same time, the load output resistor limits the output current and provides a stable output voltage. This structure can protect the capacitor module from the impact during the charging process.

[0021] Optionally, the fourth diode is a breakdown diode.

[0022] By adopting the above technical solution, when the gate voltage of the fourth transistor has an instantaneous overvoltage, the breakdown diode will quickly conduct and conduct the excess energy into the ground wire. Its fast response characteristic and good surge absorption ability can effectively prevent the gate of the fourth transistor from being damaged due to overvoltage.

[0023] Optionally, the drive circuit includes a first drive chip, a second drive chip, and an IGBT module, where: The IGBT module is respectively connected to the first drive chip and the second drive chip; the first drive chip and the second drive chip drive the IGBT module to drive the circuit breaker to complete the closing operation according to the charging voltage of the capacitor module.

[0024] By adopting the above technical solution, the IGBT module can achieve fast switching and precise current control under the control of the drive signal. Its excellent switching characteristics and low-loss features ensure the rapidity and reliability of the circuit breaker closing operation.

[0025] In summary, the beneficial effects brought by the technical solution of this application include: By adopting the above technical solution, a primary voltage stabilizing circuit is set to rectify and perform the first voltage stabilization process on the input AC power supply voltage, output the first DC voltage, and then perform the second voltage stabilization process on the first DC voltage through a secondary voltage stabilizing circuit to obtain a more stable second DC voltage. Then, the voltage conversion circuit boosts the second DC voltage to the required third DC voltage, and charges the capacitor module under the protection of the capacitor charging protection circuit. Finally, the drive circuit precisely controls the closing or opening action of the circuit breaker according to the voltage state of the capacitor module. This series design of multi-stage voltage stabilization and protection not only ensures the stability of each stage of voltage, but also avoids the possible damage to the capacitor module during the charging process through a dedicated protection circuit. At the same time, the drive circuit can perform intelligent control according to the actual voltage state of the capacitor module, thereby effectively improving the reliability of the circuit breaker during manual closing operation. Description of the Drawings

[0026] Figure 1 is a schematic diagram of the principle of a three-phase in-line permanent magnet mechanism vacuum circuit breaker with a manual closing function provided by an embodiment of this application; Figure 2 is a schematic diagram of the structure of a primary voltage stabilizing circuit provided by an embodiment of this application; Figure 3 is a schematic diagram of the structure of a secondary voltage stabilizing circuit provided by an embodiment of this application; Figure 4 is a schematic diagram of the structure of a capacitor charging protection circuit provided by an embodiment of this application.

[0027] Description of the reference numerals: C1, the first capacitor; C2, the second capacitor; C3, the third capacitor; C4, the fourth capacitor; C5, the fifth capacitor; R1, the first resistor; R2, the second resistor; R3, the third resistor; R4, the fourth resistor; R5, the fifth resistor; R6, the sixth resistor; R7, the seventh resistor; R8, the eighth resistor; R9, the ninth resistor; R0, the protection resistor; Rl, the load resistor; Rload, the load output resistor; Q1, the first transistor; Q2, the second transistor; Q3, the third transistor; Q4, the fourth transistor; D1, the first diode; D2, the second diode; D3, the third diode; D4, the fourth diode. Detailed Embodiments

[0028] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this specification. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments.

[0029] In the description of the embodiments of this application, words such as "exemplary", "for example", or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design solution described as "exemplary", "for example", or "for instance" in the embodiments of this application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of words such as "exemplary", "for example", or "for instance" is intended to present relevant concepts in a specific manner.

[0030] In the description of the embodiments of this application, the meaning of the term "plurality" refers to two or more. For example, a plurality of systems means two or more systems, and a plurality of screen terminals means two or more screen terminals. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. The terms "include", "comprise", "have" and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0031] Please refer to Figure 1 , which is a schematic diagram of the principle of a three-phase in-line permanent magnet mechanism vacuum circuit breaker with a manual closing function provided for the embodiments of this application.

[0032] Combined with Figure 1 , the working principle of this application will be briefly described first. On the basis of the existing permanent magnet mechanism circuit breaker, a manual closing mechanism is added, which is independent of the existing manual tripping mechanism. By "pulling up and down" through an external manual closing handle sling (similar to the outside of a spring closing mechanism), the permanent magnet AC generator is driven to work through a gearbox. The output AC power supply voltage is rectified, filtered, and regulated through a first-level voltage regulation circuit to obtain a relatively stable first DC voltage. Then, a stable second DC voltage is obtained through a second-level voltage regulation circuit. The second DC voltage is boosted to a third DC voltage through a DC / DC voltage conversion module, and the dedicated closing capacitor of the manual closing mechanism is charged through a pre-set capacitor charging protection module. When the voltage at the capacitor module terminal exceeds the discharge threshold, and the charging threshold is a preset critical point (generally set to DC230V), the IGBT drive chip enable terminal is turned on, and the capacitor discharges to the permanent magnet mechanism coil to complete the closing.

[0033] The following will provide a detailed description of the specific structure of a three-phase in-line permanent magnet mechanism vacuum circuit breaker with a manual closing function provided by this application.

[0034] The circuit breaker includes a primary voltage stabilization circuit, a secondary voltage stabilization circuit, a voltage conversion circuit, a capacitor charging protection circuit, and a drive circuit. The primary voltage stabilization circuit, the secondary voltage stabilization circuit, the voltage conversion circuit, the capacitor charging protection circuit, and the drive circuit are connected in series in sequence, where: The primary voltage stabilization circuit is used to rectify and perform the first voltage stabilization processing on the input AC power supply voltage, and output the first DC voltage; The secondary voltage stabilization circuit is used to perform the second voltage stabilization processing on the first DC voltage to obtain the second DC voltage; The voltage conversion circuit is used to boost the second DC voltage to the third DC voltage; The capacitor charging protection circuit is used to protect the capacitor module of the circuit breaker during charging; The drive circuit is used to drive the circuit breaker to close according to the voltage state of the capacitor module.

[0035] Specifically, the primary voltage stabilization circuit receives the AC power supply voltage generated by the manual operation permanent magnet generator, converts the alternating current into pulsating direct current through the rectifier circuit, and then through filtering and voltage stabilization processing, outputs a relatively stable first DC voltage. The secondary voltage stabilization circuit receives the first DC voltage, and performs secondary regulation and stabilization on the voltage through a more precise voltage stabilization processing circuit, and outputs a second DC voltage with smaller fluctuations and higher stability. The voltage conversion circuit adopts DC / DC conversion technology to boost the stable DC voltage output by the secondary voltage stabilization to a higher voltage level required for charging the capacitor module, and outputs the third DC voltage. The capacitor charging protection circuit plays a protective role during the charging process of the capacitor module. The drive circuit drives the circuit breaker to complete the closing operation when the voltage reaches the preset threshold according to the voltage state of the capacitor module.

[0036] Based on the above embodiments, as an optional implementation manner, please refer to Figure 2 , which is a schematic structural diagram of a primary voltage stabilization circuit provided by an embodiment of this application. The primary voltage stabilization circuit includes a power transformer, a bridge rectifier, and a first voltage stabilization unit, where: The primary coil of the power transformer is connected to the power supply, and the secondary coil of the power transformer is connected to the input end of the bridge rectifier; The positive output of the bridge rectifier is connected to the input end of the first voltage stabilization unit, and the negative output of the bridge rectifier is grounded; The output end of the first voltage stabilization unit is connected to the secondary voltage stabilization circuit.

[0037] In specific implementation, the primary coil of the power transformer is connected to the AC power supply generated by manual operation. Since there may be significant fluctuations in the voltage amplitude generated by manual operation, while achieving electrical isolation, the power transformer converts the input voltage to an appropriate voltage level, and the AC voltage output from its secondary coil is connected to the input terminal of the bridge rectifier.

[0038] The bridge rectifier adopts a full-wave rectification circuit. Its input terminal receives the AC voltage output from the secondary coil of the power transformer, and converts the alternating current into unidirectional pulsating direct current through the rectification of four diodes. The rectified voltage is output from the positive output terminal of the bridge rectifier. The positive output terminal of the bridge rectifier is connected to the input terminal of the first voltage stabilization unit, and in the first voltage stabilization unit, the rectified voltage is filtered and voltage-stabilized through voltage-stabilizing components. The output terminal of the first voltage stabilization unit is connected to the secondary voltage stabilization circuit to provide a relatively stable DC voltage input for subsequent fine voltage stabilization processing.

[0039] Based on the above embodiments, as an optional implementation manner, the first voltage stabilization unit includes a voltage stabilizer, a first capacitor, a second capacitor, a first diode, a second diode, a first resistor, a second resistor, and a load resistor. The second resistor is a variable resistor, where: The first terminal of the voltage stabilizer is grounded through the second capacitor; The third terminal of the voltage stabilizer is grounded through the first capacitor. The third terminal of the voltage stabilizer serves as the input terminal of the first voltage stabilization unit and is connected to the positive output terminal of the bridge rectifier; The first terminal of the first resistor is connected to the second terminal of the voltage stabilizer, the second terminal of the first resistor is connected to the first terminal of the voltage stabilizer, and the second terminal of the first resistor is grounded through the second resistor; The positive electrode of the second diode is connected to the second terminal of the first resistor, the negative electrode of the second diode is connected to the positive electrode of the first diode, and the negative electrode of the first diode is connected to the third terminal of the voltage stabilizer; The first terminal of the load resistor is connected to the first terminal of the first resistor, the second terminal of the load resistor is grounded, and the first terminal of the load resistor serves as the output terminal of the first voltage stabilization unit and is connected to the secondary voltage stabilization circuit.

[0040] The first voltage stabilizing unit adopts a composite voltage stabilizing circuit design based on a voltage regulator. Through the collaborative work of multiple capacitors, diodes, and resistors, it realizes effective voltage stabilization processing for the output voltage of the bridge rectifier. Its third terminal receives the pulsating DC voltage output by the bridge rectifier as the input terminal, and is grounded through the first capacitor to achieve filtering at the input terminal. The first terminal of the voltage regulator is grounded through the second capacitor to suppress high-frequency ripples at the output terminal and improve the voltage stabilization effect. A first resistor is connected between the first terminal and the second terminal of the voltage regulator to form the basic bias circuit of the voltage regulator. The other end (second terminal) of the first resistor is grounded through a variable resistor (second resistor). This design allows the operating point of the voltage stabilizing circuit to be finely adjusted by adjusting the resistance value of the second resistor, improving the adaptability and voltage stabilization accuracy of the circuit. To provide additional voltage stabilization protection, a protection branch composed of a first diode and a second diode is added to the circuit. The positive electrode of the second diode is connected to the second terminal of the first resistor, its negative electrode is connected to the positive electrode of the first diode, and the negative electrode of the first diode is connected to the input terminal (third terminal) of the voltage regulator. This diode branch can provide effective clamping protection when the input voltage fluctuates abnormally, preventing overvoltage from damaging the circuit. The load resistor is set as both the load of the voltage stabilizing circuit and the voltage sampling resistor. Its first terminal is connected to the first terminal of the first resistor and serves as the output terminal of the first voltage stabilizing unit to be connected to the secondary voltage stabilizing circuit, and the second terminal is grounded to complete the loop. Through the load resistor, a stable output voltage can be obtained, providing a reliable input for the subsequent secondary voltage stabilizing circuit.

[0041] Based on the above embodiments, as an alternative implementation, the primary voltage stabilizing circuit further includes a protection resistor, where: The protection resistor is respectively connected to the positive terminal of the secondary coil of the power transformer and the input positive terminal of the bridge rectifier.

[0042] In specific implementation, the protection resistor is connected in series between the positive terminal of the secondary coil of the power transformer and the input positive terminal of the bridge rectifier. When the output voltage of the secondary coil of the power transformer has an instantaneous peak value, the protection resistor can timely limit the sudden change of the current and dissipate the impact energy in the form of heat, thereby protecting the bridge rectifier from damage by excessive current.

[0043] Please refer to Figure 3 , Figure 3 which is a schematic structural diagram of a secondary voltage stabilizing circuit provided by an embodiment of the present application. Next, the secondary voltage stabilizing circuit will be described in detail in conjunction with Figure 3 .

[0044] The secondary voltage stabilizing circuit includes a third capacitor, a fourth capacitor, a fifth capacitor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a third diode, a first transistor, a second transistor, and a third transistor. The seventh resistor is a variable resistor, where: The input terminal of the secondary voltage regulation circuit is grounded through a third capacitor; The input terminal of the secondary voltage regulation circuit is respectively connected to the collector of the second transistor and the collector of the third transistor. The base of the third transistor is grounded through a fourth capacitor, and the emitter of the third transistor is connected to the base of the second transistor; The output terminal of the primary voltage regulation circuit is connected to the emitter of the first transistor through a third resistor, and the collector of the first transistor is connected to the emitter of the second transistor through a fourth resistor; The negative electrode of the third diode is connected to the collector of the first transistor, and the positive electrode of the third diode is grounded; The emitter of the second transistor is grounded through a fifth resistor, a seventh resistor and a sixth resistor connected in series, and the base of the first transistor is connected to the sliding end of the seventh resistor; The positive electrode of the fifth capacitor is connected to the emitter of the second transistor, the negative electrode of the fifth capacitor is grounded, and the positive electrode of the fifth capacitor serves as the output terminal of the secondary voltage regulation circuit and is connected to the capacitor charging protection circuit.

[0045] Specifically, the AC signal at the input terminal is preliminarily filtered through a capacitor to ground and then enters the main voltage regulation circuit composed of three transistors. In the main circuit, the collectors of the third transistor and the second transistor are directly connected to the input terminal. Among them, the base of the third transistor is grounded through a filtering capacitor to obtain a stable bias, and its emitter is connected to the base of the second transistor to form a driving relationship. This connection method enables the third transistor to provide a stable base drive voltage for the second transistor.

[0046] The first transistor receives the input signal through a current-limiting resistor, and its collector is connected to the emitter of the second transistor through another resistor. To protect the first transistor from reverse voltage damage, a third diode is connected in parallel at its collector terminal, and the positive electrode of the third diode is grounded to form a protection branch.

[0047] In the biasing part, a structure of three resistors connected in series to ground is adopted, with a variable resistor in the middle. The base of the first transistor is connected to the sliding end of this variable resistor. By adjusting the position of the sliding end, the operating point of the first transistor can be precisely controlled, thereby realizing fine-tuning of the entire voltage regulation circuit. When the output second DC voltage is too high, the base-emitter voltage decreases, the conduction of the second transistor decreases, and the current of the third transistor decreases, thereby reducing the second output voltage. When the output second DC voltage is too low, the base-emitter voltage increases, and the transistor conducts more, thereby increasing the second output voltage. A large-capacity capacitor is used at the output terminal of the secondary voltage regulation circuit, and the second capacitor can play a filtering role.

[0048] Optionally, the third diode is a Zener diode.

[0049] A Zener diode is different from an ordinary diode. It has a special reverse breakdown characteristic. When the reverse voltage reaches its Zener voltage, a stable Zener breakdown will occur, and the voltage across the diode will remain at a relatively constant value. In a secondary voltage regulation circuit, the third diode is connected in parallel between the collector of the first transistor and the ground, with its positive pole grounded. This connection mode makes it operate in a reverse-biased state. When the collector voltage of the first transistor attempts to exceed the Zener voltage due to certain reasons (such as load mutation, input voltage fluctuation, etc.), the Zener diode will conduct immediately, clamping the excessive voltage at the Zener voltage value, thus playing a dual protection role.

[0050] Optionally, the first transistor, the second transistor, and the third transistor are all NPN-type triodes.

[0051] Among them, the collector of the third transistor is directly connected to the input power supply, and the base is grounded through a capacitor to obtain a stable bias. When there is a positive voltage at the base, the current flows from the collector to the emitter, and the changing input voltage will cause a slight change in the base voltage. This change is amplified and a corresponding current change is generated at the emitter. The emitter is directly connected to the base of the second transistor, forming a driving relationship.

[0052] The second transistor receives the voltage from the emitter of the third transistor as the base bias. When the emitter voltage of the third transistor changes, the base voltage of the second transistor also changes accordingly. An increase in the base voltage will increase the conduction degree of the transistor, causing the current from the collector to the emitter to increase; a decrease in the base voltage will reduce the conduction degree, and the current will decrease accordingly.

[0053] The base of the first transistor is connected to the sliding end of the variable resistor, and the base voltage can be controlled by adjustment. Its collector is connected to the emitter of the second transistor. When the base voltage rises, the conduction degree of the transistor increases, and the collector current increases; when the base voltage drops, the conduction degree decreases, and the collector current decreases.

[0054] The series cooperation of the three NPN-type triodes forms a complete feedback loop. The change in the input voltage is first detected and amplified by the third transistor, adjusted by the second transistor, and finally precisely controlled by the first transistor. This design utilizes the current amplification characteristic of the NPN-type triode.

[0055] In this embodiment, the voltage conversion circuit is a DC boost circuit, and its circuit structure can adopt a typical boost topology.

[0056] An alternative implementation is that the voltage conversion circuit consists of components such as an input filter capacitor, a MOSFET switch, a power inductor, a fast recovery diode, and an output filter capacitor. The filter capacitor at the input end is used to filter out the ripple of the input voltage, and a fuse is set at the input end for overcurrent protection. The core control of the circuit uses a PWM controller to achieve the functions of voltage boost and voltage regulation by adjusting the switching duty cycle of the MOSFET.

[0057] The specific working principle is as follows: When the MOSFET is turned on, the input power supply stores energy through the inductor, and the inductor current gradually increases. The output capacitor then supplies energy to the load. When the MOSFET is turned off, the energy stored in the inductor is released to the output capacitor and the load through the fast recovery diode, and the output voltage increases at this time. By controlling the switching timing of the MOSFET, the conversion from the input voltage to a higher output voltage can be achieved.

[0058] Please refer to Figure 4 , Figure 4 which is a schematic diagram of a capacitor charging protection circuit provided by an embodiment of this application. Next, in combination with Figure 4 , the capacitor charging protection circuit will be described in detail.

[0059] The capacitor charging protection circuit includes an eighth resistor, a ninth resistor, a fourth transistor, a fourth diode, and a load output resistor, where: The positive input of the capacitor charging protection circuit is connected to the gate of the fourth transistor through the eighth resistor, and the drain and source of the fourth transistor are grounded; The positive electrode of the fourth diode is grounded, and the negative electrode of the fourth diode is connected to the gate of the fourth transistor; One end of the ninth resistor is connected to the gate of the fourth transistor, and the other end of the ninth resistor is grounded; The positive output of the capacitor charging protection circuit is grounded through the load output resistor.

[0060] The design of this capacitor charging protection circuit is mainly used to prevent overshoot during the capacitor charging process and protect the subsequent circuit. In the circuit implementation, the positive input is first connected to the gate of the fourth transistor through the eighth resistor, and this eighth resistor plays a current limiting role to prevent excessive gate current. The fourth transistor uses a MOSFET device, and its drain and source are both grounded, enabling it to quickly conduct and discharge excess charge under control.

[0061] To protect the gate of the fourth transistor from reverse voltage damage, a fourth diode is connected in parallel at the gate end, with its positive electrode grounded and its negative electrode connected to the gate of the fourth transistor. When a reverse voltage appears, the diode conducts and clamps the reverse voltage, effectively protecting the gate of the MOSFET. At the same time, a ninth resistor is connected between the gate of the fourth transistor and the ground, forming a stable gate bias network to ensure that the transistor remains in a determined state when there is no input signal and to avoid malfunction caused by gate voltage drift.

[0062] At the output end, the positive output of the circuit is grounded through a load output resistor. The function of this resistor is to limit the output current and also provide a certain buffering effect when the load changes. When the input voltage rises, the fourth transistor adjusts its conduction state in a timely manner according to the change of the gate voltage, thereby controlling the magnitude of the charging current. If an overvoltage situation occurs, the fourth transistor increases its conduction degree and conducts the excess charge to the ground wire, playing a protective role.

[0063] Optionally, the fourth diode is a breakdown diode.

[0064] In practical applications, when selecting a breakdown diode, the maximum withstand voltage of the gate of the fourth transistor needs to be considered. Usually, a device with a breakdown voltage slightly lower than the maximum withstand voltage of the gate is selected. In this way, when an abnormal voltage appears, the breakdown diode will conduct before the gate voltage reaches a dangerous value, limiting the excessive voltage within a safe range. Since the breakdown diode has an extremely fast response speed and can complete the conduction process at the nanosecond level, it can effectively prevent transient overvoltage from damaging the fourth transistor.

[0065] By using the breakdown diode, the protection circuit achieves more precise voltage control and a more reliable protection function. When the system is operating normally, the breakdown diode is in a high-resistance state and does not affect the normal operation of the circuit; when an abnormality occurs, the breakdown diode can conduct quickly and conduct the excess energy to the ground wire.

[0066] Based on the above embodiments, as an optional implementation manner, the drive circuit includes a first drive chip, a second drive chip, and an IGBT module, where: The IGBT module is respectively connected to the first drive chip and the second drive chip; the first drive chip and the second drive chip drive the IGBT module to drive the circuit breaker to complete the closing operation according to the charging voltage of the capacitor module.

[0067] In specific implementation, both the first driving chip and the second driving chip are directly connected to the IGBT module. They receive the charging voltage signal of the capacitor module and adjust the timing and intensity of the driving signal according to this voltage value. When the charging voltage of the capacitor module reaches the preset value, the two driving chips will output driving signals simultaneously to ensure that the IGBT module can enter the conduction state quickly and stably. After receiving the driving signal, the IGBT module is responsible for converting the electrical energy stored in the capacitor module into the current for driving the circuit breaker to close.

[0068] In the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0069] The above description is only an exemplary embodiment of the present disclosure and should not be used to limit the scope of the present disclosure. That is, any equivalent changes and modifications made in accordance with the teachings of the present disclosure still fall within the scope covered by the present disclosure. Those skilled in the art will easily think of other implementation schemes of the present disclosure after considering the specification and the disclosure of the practical truth. This application aims to cover any variations, uses or adaptive changes of the present disclosure, and these variations, uses or adaptive changes follow the general principles of the present disclosure and include the common general knowledge or conventional technical means in the technical field not recorded in the present disclosure.

Claims

1. A three-phase single-phase in-line permanent magnet mechanism vacuum circuit breaker with manual closing function, characterized in that: The circuit breaker comprises a primary voltage stabilizing circuit, a secondary voltage stabilizing circuit, a voltage conversion circuit, a capacitor charging protection circuit and a driving circuit, wherein the primary voltage stabilizing circuit, the secondary voltage stabilizing circuit, the voltage conversion circuit, the capacitor charging protection circuit and the driving circuit are connected in series in sequence, wherein: The primary voltage stabilizing circuit is used to perform rectification and a first voltage stabilization process on the input AC power supply voltage, and output a first DC voltage; The secondary voltage stabilization circuit is used to perform a second voltage stabilization process on the first DC voltage to obtain a second DC voltage; The voltage conversion circuit is used to boost the second DC voltage to a third DC voltage; The capacitor charging protection circuit is used to protect the capacitor module of the circuit breaker during charging; The driving circuit is used to drive the circuit breaker to complete the closing operation according to the voltage state of the capacitor module.

2. The three-phase single-phase in-line permanent magnet mechanism vacuum circuit breaker with manual closing function according to claim 1 is characterized in that: The primary voltage stabilization circuit includes a power transformer, a bridge rectifier and a first voltage stabilization unit, wherein: The primary coil of the power transformer is connected to the power supply, and the secondary coil of the power transformer is connected to the input end of the bridge rectifier; The output positive electrode of the bridge rectifier is connected to the input end of the first voltage stabilizing unit, and the output negative electrode of the bridge rectifier is grounded; The output end of the first voltage stabilizing unit is connected to the secondary voltage stabilizing circuit.

3. The three-phase single-phase in-line permanent magnet mechanism vacuum circuit breaker with manual closing function according to claim 2 is characterized in that: The first voltage stabilizing unit includes a voltage stabilizer, a first capacitor, a second capacitor, a first diode, a second diode, a first resistor, a second resistor and a load resistor, wherein the second resistor is a variable resistor, wherein: The first end of the voltage stabilizer is grounded via the second capacitor; The third end of the voltage stabilizer is grounded via the first capacitor, and the third end of the voltage stabilizer is connected to the output positive electrode of the bridge rectifier as the input end of the first voltage stabilizing unit; The first end of the first resistor is connected to the second end of the voltage regulator, the second end of the first resistor is connected to the first end of the voltage regulator, and the second end of the first resistor is grounded via the second resistor; The anode of the second diode is connected to the second end of the first resistor, the cathode of the second diode is connected to the anode of the first diode, and the cathode of the first diode is connected to the third end of the voltage regulator; The first end of the load resistor is connected to the first end of the first resistor, the second end of the load resistor is grounded, and the first end of the load resistor is connected to the secondary voltage stabilization circuit as an output end of the first voltage stabilization unit.

4. The three-phase single-phase in-line permanent magnet mechanism vacuum circuit breaker with manual closing function according to claim 2 is characterized in that: The primary voltage stabilization circuit further includes a protection resistor, wherein: The protection resistor is connected to the positive pole of the secondary coil of the power transformer and the positive pole of the input of the bridge rectifier respectively.

5. The three-phase single-phase in-line permanent magnet mechanism vacuum circuit breaker with manual closing function according to claim 1, characterized in that: The secondary voltage stabilization circuit includes a third capacitor, a fourth capacitor, a fifth capacitor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a third diode, a first transistor, a second transistor and a third transistor, wherein the seventh resistor is a variable resistor, wherein: The input end of the secondary voltage stabilizing circuit is grounded via the third capacitor; The input end of the secondary voltage stabilizing circuit is respectively connected to the collector of the second transistor and the collector of the third transistor, the base of the third transistor is grounded via the fourth capacitor, and the emitter of the third transistor is connected to the base of the second transistor; The output end of the primary voltage stabilizing circuit is connected to the emitter of the first transistor via the third resistor, and the collector of the first transistor is connected to the emitter of the second transistor via the fourth resistor; The cathode of the third diode is connected to the collector of the first transistor, and the anode of the third diode is grounded; The emitter of the second transistor is connected to ground in series via the fifth resistor, the seventh resistor and the sixth resistor, and the base of the first transistor is connected to the sliding end of the seventh resistor; The positive electrode of the fifth capacitor is connected to the emitter of the second transistor, the negative electrode of the fifth capacitor is grounded, and the positive electrode of the fifth capacitor is connected to the capacitor charging protection circuit as the output end of the secondary voltage stabilization circuit.

6. The three-phase single-phase in-line permanent magnet mechanism vacuum circuit breaker with manual closing function according to claim 5, characterized in that: The third diode is a Zener diode.

7. The three-phase single-phase in-line permanent magnet mechanism vacuum circuit breaker with manual closing function according to claim 5, characterized in that: The first transistor, the second transistor and the third transistor are all NPN transistors.

8. The three-phase single-phase in-line permanent magnet mechanism vacuum circuit breaker with manual closing function according to claim 1, characterized in that: The capacitor charging protection circuit includes an eighth resistor, a ninth resistor, a fourth transistor, a fourth diode and a load output resistor, wherein: The positive input electrode of the capacitor charging protection circuit is connected to the gate of the fourth transistor via the eighth resistor, and the drain and source of the fourth transistor are grounded; The anode of the fourth diode is grounded, and the cathode of the fourth diode is connected to the gate of the fourth transistor; One end of the ninth resistor is connected to the gate of the fourth transistor, and the other end of the ninth resistor is grounded; The output positive electrode of the capacitor charging protection circuit is grounded via the load output resistor.

9. The three-phase single-phase in-line permanent magnet mechanism vacuum circuit breaker with manual closing function according to claim 8, characterized in that: The fourth diode is a breakdown diode.

10. The three-phase single-phase in-line permanent magnet mechanism vacuum circuit breaker with manual closing function according to claim 1, characterized in that: The driving circuit includes a first driving chip, a second driving chip and an IGBT module, wherein: The IGBT module is connected to the first driver chip and the second driver chip respectively; the first driver chip and the second driver chip drive the IGBT module to drive the circuit breaker to complete the closing operation according to the charging voltage of the capacitor module.

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