Microsecond-level fast power supply circuit suitable for circuit breaker

Abstract

The invention discloses a microsecond-level fast power supply circuit suitable for a circuit breaker, and the circuit comprises a mutual inductor input module which is used for inducing electric energy from the current of a circuit breaker loop; the input end of the 12V quick power supply module is electrically connected with the mutual inductor input module, the 12V quick power supply module is used for outputting a stable 12V direct current power supply within 200 microseconds, and the 12V quick power supply module comprises a rectifying and filtering unit used for converting an alternating current signal sensed by a mutual inductor into a direct current signal; and the voltage stabilization control unit is formed based on a 12V voltage-regulator tube and transistor negative feedback and is used for outputting stable 12V voltage. According to the invention, a rapid power supply circuit is innovatively designed for the circuit breaker, establishment of a 200us-level main power supply and establishment of a 2ms-level backup power supply are realized, the design advancement belongs to a domestic leading position, and a solid foundation design can be provided for intelligent manufacturing of Chinese circuit breakers.

Description

Technical Field

[0001] The present invention relates to the field of circuit breakers, and in particular to a microsecond-level fast power supply circuit suitable for circuit breakers. Background Art

[0002] As an essential component in power systems, circuit breakers' core function is to interrupt the circuit in an extremely short time when a fault current occurs, ensuring system and equipment safety. In recent years, with the widespread adoption of smart grids and high-performance power distribution systems, intelligent circuit breakers with electronic tripping as their core have gradually replaced traditional thermal-magnetic mechanical circuit breakers, becoming a key trend in high-end circuit-breaking protection solutions.

[0003] In this type of electronic circuit breaker, the power supply system, as a core support module, directly impacts its trip response time, system stability, and overall reliability. To meet the high-speed response requirements of the electronic trip unit under high-interrupting capacity (Icu) testing conditions, the power supply design must have extremely short startup time and reliable energy support capabilities. Especially in cold start scenarios (without pre-power supply), the ability to complete power establishment in microseconds is the key technical guarantee for achieving a 6-10 millisecond interruption capability.

[0004] However, both common circuit breaker power supply solutions in the prior art have obvious shortcomings:

[0005] Traditional AC-DC-based power supply design: This solution connects to an AC main power source (such as AC220V) and then rectifies and converts it into a DC power output. Although the technology is mature and the power output is stable, due to the complex rectification, filtering and voltage regulation processes, the typical startup time is often 100 to 200 milliseconds, far exceeding the electronic trip response time requirement and unable to meet the stringent startup time requirements of fast circuit breakers.

[0006] Transformer-based energy induction power supply design: This type of solution obtains energy by sensing the operating current in the circuit breaker circuit through a current transformer (CT). In theory, no additional external power supply is required, which is suitable for compact self-powered design requirements. However, most current transformer power supply solutions start slowly, and the time required to establish a 3.3V or 12V power supply generally exceeds 5 milliseconds, which makes it difficult to support high-performance electronic tripping requirements.

[0007] Furthermore, during the Icu high-current interruption test, the circuit breaker relies solely on the inductive energy of the transformer to complete all power initialization, as the AC power supply is not initially connected or the external power supply may be interrupted. This can easily lead to energy shortages or power supply delays, affecting tripping accuracy and safety performance. Therefore, a new power supply solution that can establish a stable power supply in a very short time and has dynamic energy management capabilities is urgently needed to support the practical application needs of fast-response circuit breakers. Summary of the Invention

[0008] In order to solve the above problems, the present invention provides a microsecond-level fast power supply circuit suitable for a circuit breaker, which can effectively solve the deficiencies in the prior art.

[0009] The present invention is achieved through the following technical solution: a microsecond fast power supply circuit suitable for a circuit breaker, comprising:

[0010] a transformer input module for sensing electrical energy from the current in the circuit breaker circuit;

[0011] A 12V fast power supply module, whose input end is electrically connected to the transformer input module, is used to output a stable 12V DC power supply within 200 microseconds, and includes:

[0012] The rectifier and filter unit is used to convert the AC signal sensed by the transformer into a DC signal;

[0013] The voltage stabilization control unit is based on a 12V voltage regulator tube and transistor negative feedback, and is used to output a stable 12V voltage;

[0014] A backup power supply unit, including energy storage capacitors, is used for priority competitive charging without affecting the 12V main power output;

[0015] A 3.3V fast power supply module, whose input end is electrically connected to the 12V fast power supply module and is used to output 3.3V DC power within 200 microseconds. The 3.3V fast power supply module includes:

[0016] A fast LDO voltage regulator unit, whose input receives a 12V power supply and whose output is connected to the load through a diode;

[0017] Control pin, used to receive the control signal from the normal power module to control the working state of the LDO;

[0018] A 3.3V normal power supply module, whose input end is electrically connected to the output end of the 12V fast power supply module, is used to provide a high-efficiency 3.3V DC power supply when the circuit breaker is in normal working condition.

[0019] As a preferred technical solution, the 3.3V normal power supply module includes:

[0020] The DC-DC power supply chip has its input connected to the 12V backup power supply and its output connected to the load through a diode.

[0021] As an optimal technical solution, it also includes a delayed start control circuit, which includes an RC delay network composed of resistors and capacitors and a voltage detection circuit, which is used to detect the establishment status of the 12V voltage. After the 12V voltage reaches the set threshold and stabilizes, after a preset delay time, the start and stop status of the 3.3V fast power supply module is controlled to avoid reverse interference and control the start timing of the 3.3V normal power supply module.

[0022] As a preferred technical solution, charging priority control is achieved through a charging control path composed of NPN / PNP tubes (or NMOS / PMOS) between the backup power supply unit and the 12V output in the 12V fast power supply module.

[0023] As an optimal technical solution, the backup power supply unit in the 12V fast power supply module adopts a storage capacitor design, with a typical value of 47uF~330uF and a withstand voltage of 16V~35V. The capacitor types include tantalum capacitors, solid capacitors, and electrolytic capacitors.

[0024] As a preferred technical solution, an anti-rebounce diode is connected in series to the output end of the LDO regulator in the 3.3V fast power supply module.

[0025] As a preferred technical solution, the output voltage of the 3.3V normal power supply module is set to between 3.6V and 3.7V to compensate for the voltage drop of the series diode.

[0026] As a preferred technical solution, the rectification and filtering unit includes a bridge rectifier module and multiple capacitors, and the capacitance value thereof does not exceed 100 microfarads.

[0027] As a preferred technical solution, the enable end of the DC-DC power supply chip is controlled by a delayed start circuit so that it is started after the 12V backup power supply is established, thereby ensuring the stability of the power switching process.

[0028] The beneficial effects of the present invention are as follows: First, by optimizing the rectification and energy control of the transformer power supply path, and coordinating it with a high-response LDO and 12V voltage-stabilizing feedback system, the present invention achieves stable output of 3.3V power within 180 microseconds and 12V power within 200 microseconds, significantly exceeding the hundreds of milliseconds startup time required by traditional AC-DC solutions. This significantly improves the response speed of the circuit breaker in the ICU breaking test and provides a solid power supply guarantee for 10-millisecond electronic tripping.

[0029] Second, the present invention integrates a fast-charging backup capacitor in the 12V main power path, with a 15mJ energy storage capacity that can be fully charged within 2 milliseconds, without charge or discharge restrictions. Through a dynamic competitive charging mechanism, the backup power supply can quickly compensate for power outages or sudden load changes, ensuring the continuous operation of key system components and enhancing the circuit breaker's anti-interference and continuous energy supply capabilities.

[0030] Third, the present invention constructs a competitive charging control circuit composed of transistors or MOS devices, which can intelligently determine the priority of backup power charging and main power output, ensuring that energy storage is completed without interrupting the main power output. This effectively solves the problem of "backup power charging causing main voltage jitter or delay" in traditional solutions and improves the overall stability of the system.

[0031] Fourth, this invention utilizes a dual-mode 3.3V output structure combining fast LDO power supply and efficient DC-DC power supply. The LDO mode provides a high-speed response during cold start, while the DC-DC mode takes over during steady-state operation, achieving an organic combination of fast power supply and high-efficiency operation. The DC-DC power supply efficiency can reach over 95%, effectively reducing the power consumption of the circuit breaker during long-term operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 This is a schematic diagram of a 12V power supply circuit of the present invention;

[0034] Figure 2 This is a schematic diagram of the 3.3V fast power supply of the present invention;

[0035] Figure 3 This is a schematic diagram of the 3.3V normal power supply principle of the present invention. DETAILED DESCRIPTION

[0036] All features disclosed in this specification, or all steps in the disclosed methods or processes, except mutually exclusive features and / or steps, can be combined in any manner.

[0037] Any feature disclosed in this specification (including any appended claims, abstract and drawings), unless otherwise stated, may be replaced by other equivalent or similar features. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0038] like Figure 1-Figure 3 As shown, the present invention is a microsecond fast power supply circuit suitable for circuit breakers, which combines the transformer power supply mechanism and the high-response power supply architecture to complete power supply establishment in a very short time and support the rapid action control of the circuit breaker electronic trip device.

[0039] The structure and function of the present invention are described in detail below in conjunction with specific circuit schematics to help those skilled in the art understand and implement the present invention.

[0040] The power supply circuit of the present invention as a whole comprises a mutual inductor input module, a 12V fast power supply module, a 3.3V fast power supply module and a 3.3V normal power supply module.

[0041] First, the transformer input module senses current from the circuit breaker's circuit and outputs an AC induced voltage. This module is electrically connected to the subsequent rectifier and filter module. This module uses a bridge rectifier (such as the MB6S), with its input connected to the transformer's AC output and its output connected to the filter capacitor.

[0042] Typically, the filter capacitors are multiple 100nF capacitors such as C1, C2, and C3 configured in parallel to filter out high-frequency ripples. A large-capacity capacitor C4 (such as 220μF) is also provided to provide steady-state energy support.

[0043] The 12V fast power supply module receives the rectified DC signal and then stabilizes it through a voltage stabilization control unit. This control unit uses a 12V voltage regulator tube and transistor to form a negative feedback circuit to ensure the output voltage remains stable at 12V.

[0044] The circuit includes a backup power supply unit for rapid energy storage during the normal 12V output process. This unit primarily consists of a storage capacitor, C4, with a capacity range of 47μF to 330μF. The capacitor can be a solid-state, electrolytic, or tantalum capacitor.

[0045] A control path consisting of NMOS or PMOS devices is used between the charging path of the backup power supply and the main power supply output. By using voltage comparison and gating control strategies, a competitive charging mechanism with main power priority is implemented to avoid interference with the main voltage during the backup power supply charging process.

[0046] The output stable 12V power supply is used for two modules at the same time: one is a 3.3V fast power supply module, and the other is a 3.3V normal power supply module. The 3.3V fast power supply module is used to support the circuit breaker to quickly establish power supply under ICU cold start conditions.

[0047] The module is built with a low-dropout linear regulator (LDO) chip (such as ME6215C33M5G). The input receives a 12V voltage and the output outputs a stable 3.3V voltage. This voltage is output through diode D14 to prevent the backflow current in other paths from interfering with the normal operation of the LDO.

[0048] Capacitors C10 and C11, 100nF and 10μF respectively, are set between the LDO output and ground to improve output stability and filter ripple noise.

[0049] The LDO chip also has an enable pin (CE), which receives a control level signal from a 3.3V normal power supply module.

[0050] When the latter is operating stably, a control level turns off the LDO, avoiding redundant power supply paths. This control level is generated by a delayed startup control circuit that detects the 12VCAP voltage and delays turning off the LDO after it rises to a set threshold, ensuring a smooth and conflict-free power supply switching process.

[0051] The 3.3V normal power supply module is used to provide a high-efficiency, stable power supply when the circuit breaker is operating normally. Its core is a DC-DC converter chip (such as the MT2492). Its input is connected to the 12VCAP terminal, and its output outputs a 3.3V voltage through diode D15.

[0052] To compensate for the forward voltage drop of the diode, the output voltage of the DC-DC chip is set to 3.6V~3.7V, so that the load power supply capability of 3.3V can still be maintained after the voltage drop of D15.

[0053] The module's feedback pin, FB, is connected to voltage-divider resistors R6 (30kΩ) and R7 (10kΩ) to precisely control the output voltage and ensure voltage stability. The DC-DC chip's enable pin, EN, connects to a delayed-start control unit composed of capacitors and resistors. This delays the start of normal power after the 12VCAP voltage stabilizes, preventing interference between the LDO and the DC-DC during the initial power supply phase.

[0054] Specifically, the delayed start control circuit is used to coordinate the power supply switching between the 3.3V fast power supply module (LDO) and the 3.3V normal power supply module (DC-DC power supply chip) to avoid power supply conflict or reverse interference during the cold start of the circuit breaker.

[0055] Specifically, the delayed start control circuit is composed of an RC delay network composed of capacitors and resistors, and is constructed in conjunction with a voltage detection circuit. After the 12VCAP port voltage reaches the set threshold, after a certain time delay, it outputs a control signal to switch the enable state of the LDO.

[0056] The specific implementation method is as follows: When the circuit breaker is first activated, the transformer sensing output is insufficient to immediately support the normal DC-DC power supply startup. Therefore, the LDO fast power supply module starts first to ensure that the SoC and related loads can obtain a fast and stable 3.3V power supply during the cold start phase;

[0057] As the transformer induced voltage gradually builds up, when the 12VCAP port voltage reaches the set threshold (e.g., 10V to 12V) and remains stable, the delayed startup control circuit delays the RC charging and sends a shutdown signal to the LDO enable pin (LDO_EN), shutting down the fast LDO power supply path to avoid parallel power supply conflicts with the DC-DC normal power supply module.

[0058] At the same time, the delayed start control circuit controls the enable terminal (EN) of the DC-DC power supply chip, so that it starts again after the 12VCAP voltage is stably established, thereby completing the smooth switching of the 3.3V power supply from the fast power supply module to the normal power supply module.

[0059] The above-mentioned delayed start control circuit can use a voltage-dividing resistor to detect the 12VCAP voltage, and generate a delay signal through an RC circuit formed by combining it with a delay capacitor, or use a simple comparator chip (such as LM393) to assist in voltage monitoring and delay control. It has the advantages of simple circuit, low cost and stable response.

[0060] A π-type filter consisting of inductor L1 (10μH) and capacitor C6 (10μF) is also provided in the module to suppress switching ripple and improve output quality.

[0061] The BST pin of the chip is connected to the switch pin SW through capacitor C5 (10nF) to improve the driving capability of the high-side MOS tube and enhance the load response performance.

[0062] The power supply circuit of the present invention can not only complete the establishment of key power supply paths including 12V and 3.3V within 200 microseconds, but also realize power supply adaptation to different operating scenarios through backup energy storage design and dynamic power switching mechanism, and is particularly suitable for the rapid action requirements under the circuit breaker ICU working conditions.

[0063] The entire power supply system boasts a compact structure, fast response, and high energy efficiency, delivering exceptional performance in cold start, high-frequency tripping, and stable operation. Field tests have demonstrated that the system can stably support electronic tripping systems, completing the disconnection process within 10 milliseconds, with the main power supply establishment time exceeding 200 microseconds, demonstrating promising industrial application prospects.

[0064] The present invention innovatively designs a fast power supply circuit, which can achieve 200us-level power establishment and 2ms backup power supply through mutual inductor power supply, and has excellent normal power supply efficiency.

[0065] This circuit invention has passed the 50kAIcu breaking test (250A frame current) and achieved a pure electronic tripping time of 10ms in the cold start 0 breaking test. The 3.3V power supply establishment time is only 180us, and the 12V power supply complete establishment time is only 200us. The test fully verifies the reliability and practicality of this invention design.

[0066] This invention innovatively designs a fast power supply circuit for the circuit breaker, which can achieve the establishment of the main power supply at the 200us level and the backup power supply at the 2ms level. The advanced design is in the leading position in China and can lay a solid foundation for the basic design of intelligent manufacturing of circuit breakers in China.

[0067] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that are not conceived through creative work should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection defined in the claims.

Claims

1. A microsecond fast power supply circuit suitable for a circuit breaker, characterized in that: include: a transformer input module for sensing electrical energy from the current in the circuit breaker circuit; A 12V fast power supply module, whose input end is electrically connected to the transformer input module, is used to output a stable 12V DC power supply within 200 microseconds, and includes: The rectifier and filter unit is used to convert the AC signal sensed by the transformer into a DC signal; The voltage stabilization control unit is based on a 12V voltage regulator tube and transistor negative feedback, and is used to output a stable 12V voltage; A backup power supply unit, including energy storage capacitors, is used for priority competitive charging without affecting the 12V main power output; A 3.3V fast power supply module, whose input end is electrically connected to the 12V fast power supply module and is used to output 3.3V DC power within 200 microseconds. The 3.3V fast power supply module includes: A fast LDO voltage regulator unit, whose input receives a 12V power supply and whose output is connected to the load through a diode; Control pin, used to receive the control signal from the normal power module to control the working state of the LDO; A 3.3V normal power supply module, whose input end is electrically connected to the output end of the 12V fast power supply module, is used to provide a high-efficiency 3.3V DC power supply when the circuit breaker is in normal working condition.

2. The microsecond fast power supply circuit suitable for circuit breaker according to claim 1, characterized in that: The 3.3V normal power supply module includes: The DC-DC power supply chip has its input connected to the 12V backup power supply and its output connected to the load through a diode.

3. The microsecond fast power supply circuit suitable for a circuit breaker according to claim 2, characterized in that: It also includes a delayed start control circuit, which includes an RC delay network composed of resistors and capacitors and a voltage detection circuit, which is used to detect the establishment status of the 12V voltage. After the 12V voltage reaches the set threshold and stabilizes, after a preset delay time, the start and stop status of the 3.3V fast power supply module is controlled to avoid reverse interference and control the start timing of the 3.3V normal power supply module.

4. The microsecond fast power supply circuit suitable for a circuit breaker according to claim 1, characterized in that: The charging priority control is achieved through a charging control path formed by an NPN / PNP tube (or NMOS / PMOS) between the backup power supply unit and the 12V output in the 12V fast power supply module.

5. The microsecond fast power supply circuit suitable for circuit breaker according to claim 1, characterized in that: The backup power supply unit in the 12V fast power supply module adopts an energy storage capacitor design, the typical capacitance value of which is 47uF~330uF, the withstand voltage value is 16V~35V, and the capacitor types include tantalum capacitors, solid capacitors, and electrolytic capacitors.

6. The microsecond fast power supply circuit suitable for circuit breaker according to claim 1, characterized in that: An anti-rebounce diode is connected in series to the output end of the LDO voltage regulator in the 3.3V fast power supply module.

7. The microsecond fast power supply circuit suitable for a circuit breaker according to claim 1, characterized in that: The output voltage of the 3.3V normal power supply module is set to between 3.6V and 3.7V to compensate for the voltage drop of the series diode.

8. The microsecond fast power supply circuit suitable for a circuit breaker according to claim 1, characterized in that: The rectification and filtering unit includes a bridge rectifier module and a plurality of capacitors, the capacitance of which does not exceed 100 microfarads.

9. The microsecond fast power supply circuit suitable for a circuit breaker according to claim 1, characterized in that: The enable terminal of the DC-DC power supply chip is controlled by a delayed start circuit so that it is started after the 12V backup power supply is established, thereby ensuring the stability of the power switching process.

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