A smart circuit breaker

Abstract

This invention discloses an intelligent circuit breaker, comprising a circuit breaker control module and a tripping mechanism. The circuit breaker control module includes: a sampling isolation circuit for acquiring voltage signals between the live wire (L) and the neutral wire (N), the live wire (L) and the ground wire (PE), and the neutral wire (N) and the ground wire (PE), and also for isolating the line input terminal and acquiring the current signal of the ground wire (PE); an MCU controller, connected to the sampling isolation circuit and the tripping mechanism respectively, for determining whether the voltage signal and / or current signal reaches the protection threshold, and controlling the tripping mechanism to operate when the voltage signal and / or current signal reaches the protection threshold, thereby tripping the circuit breaker; and a back-end isolation circuit, disposed between the MCU controller and the tripping mechanism. This invention can acquire and monitor over / under voltage signals and current signals, and through isolation, ensures that the MCU controller is not affected by electromagnetic radiation from lightning strikes, keeping the intelligent circuit breaker always under control.

Description

Technical Field

[0001] This invention relates to the field of circuit breaker technology, and in particular to an intelligent circuit breaker. Background Technology

[0002] Existing intelligent circuit breakers typically obtain the voltage between the live wire (L) and the neutral wire through an "over / under voltage protection circuit" to achieve over / under voltage protection and automatic recovery functions. This type of intelligent circuit breaker only monitors the voltage between the live and neutral wires, offering limited protection capabilities. Furthermore, existing over / under voltage protection circuits (also known as voltage sampling circuits) usually involve stepping the voltage down to a certain value using an resistor-capacitor circuit before processing it with an operational amplifier circuit, and then sending the corresponding signal to the MCU. This results in existing intelligent circuit breakers having low overvoltage values ​​(less than 600V) and long tripping times, typically around 100ms, thus failing to meet the requirements of harsh environments (such as lightning strikes) in some unattended wireless communication base stations. In addition, existing intelligent circuit breakers lack isolation between the MCU front-end and back-end, or if isolation is implemented, it is costly or ineffective, making the MCU controller susceptible to electromagnetic radiation from lightning strikes, thus preventing normal operation. Summary of the Invention

[0003] The main objective of this invention is to propose an intelligent circuit breaker that can comprehensively acquire and monitor over- and under-voltage signals as well as current signals. Through isolation, the MCU controller is protected from electromagnetic radiation from lightning strikes, ensuring that the intelligent circuit breaker is always under control and protecting the back-end equipment of the intelligent circuit breaker.

[0004] The present invention adopts the following technical solution:

[0005] A smart circuit breaker includes a circuit breaker control module and a tripping mechanism; the circuit breaker control module includes:

[0006] The sampling isolation circuit includes a voltage acquisition isolation circuit and a current acquisition circuit; the voltage acquisition isolation circuit is used to acquire the voltage signal between the live wire L and the neutral wire N, the voltage signal between the live wire L and the ground wire PE, and the voltage signal between the neutral wire N and the ground wire PE, and is also used to isolate the line input terminal; the current acquisition circuit is used to acquire the current signal of the ground wire PE;

[0007] The MCU controller is connected to the sampling isolation circuit and the tripping mechanism respectively. It is used to determine whether the voltage signal and / or current signal has reached the protection threshold, and when the voltage signal and / or current signal reaches the protection threshold, it controls the tripping mechanism to work, and the circuit breaker to open.

[0008] A back-end isolation circuit is disposed between the MCU controller and the tripping mechanism to protect the MCU controller.

[0009] Preferably, the voltage acquisition isolation circuit includes three voltage transformers; the current acquisition circuit includes one grounding current transformer; the three voltage transformers are respectively used to acquire the voltage signal between the live wire L and the neutral wire N, the voltage signal between the live wire L and the ground wire PE, and the voltage signal between the neutral wire N and the ground wire PE; the grounding current transformer is used to acquire the current signal of the ground wire PE.

[0010] Preferably, the sampling isolation circuit further includes four diodes; one diode is disposed between each voltage transformer and the MCU controller; and one diode is disposed between the grounding current transformer and the MCU controller.

[0011] Preferably, the diode is a bidirectional diode.

[0012] Preferably, the sampling isolation circuit further includes four capacitors; one capacitor is provided between each voltage transformer and the MCU controller; and one capacitor is provided between the grounding current transformer and the MCU controller.

[0013] Preferably, the back-end isolation circuit includes a capacitor isolation chip.

[0014] Preferably, the circuit breaker control module further includes a communication module; the communication module is connected to the MCU controller and the host computer respectively, and is used to realize bidirectional communication between the MCU controller and the host computer.

[0015] Preferably, the communication module includes a serial communication module and / or a network communication module.

[0016] Preferably, the circuit breaker control module further includes an energy metering chip; the energy metering chip is disposed between the sampling isolation circuit and the MCU controller.

[0017] Preferably, the intelligent circuit breaker further includes: an electric operating mechanism; the MCU controller is connected to the electric operating mechanism to control the operation of the electric operating mechanism, and the circuit breaker realizes opening / closing.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] (1) This invention samples the voltage values ​​between the live wire and the neutral wire, the live wire and the ground wire, and the ground wire and the neutral wire through a voltage transformer, and collects the current signal of the ground wire PE through a ground current transformer (GCT), thereby comprehensively collecting and monitoring the over- and under-voltage signals and current signals of the intelligent circuit breaker, so as to achieve all-round protection of the back-end equipment from lightning damage.

[0020] (2) This invention uses a voltage transformer with isolation function at the input end to isolate it from the front-end line without affecting the signal input. At the back end, a back-end isolation circuit is used to isolate the MCU controller from the back-end tripping mechanism, electric operating mechanism, and communication module, etc. The back-end isolation circuit uses a low-cost capacitor isolation chip. The front-end and back-end isolation scheme of this invention ensures that the MCU controller is relatively independent and is not affected by the electromagnetic radiation of lightning strikes at the front and back ends. That is to say, even during a lightning strike, the MCU controller can still operate normally without being affected, thereby ensuring that the intelligent circuit breaker is always in a controlled state, thus protecting the customer's back-end equipment.

[0021] (3) This invention communicates with the host computer through the communication module, and can upload the opening and closing information of the intelligent circuit breaker and information such as lightning strike faults to the host computer through the RS485 bus, and monitor the usage status of the circuit breaker through the host computer, thereby facilitating remote self-diagnosis by customers; in addition, remote control of opening and closing can also be realized through the host computer.

[0022] (4) When the present invention determines that any one of the voltage signals between the live wire L and the neutral wire N, the voltage signals between the live wire L and the ground wire PE, the voltage signals between the neutral wire N and the ground wire PE, and the current signal of the ground wire PE exceeds the protection threshold, the tripping mechanism can be tripped quickly within 60ms, thereby protecting the intelligent circuit breaker itself and the downstream equipment.

[0023] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are listed below.

[0024] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0025] Figure 1 This is a structural block diagram of an embodiment of the present invention;

[0026] Figure 2 This is a circuit diagram of an embodiment of the present invention;

[0027] Figure 3 This is a flowchart of the MCU control process according to an embodiment of the present invention;

[0028] Figure 4 This is the timing diagram for tripping within 60ms according to the present invention. Detailed Implementation

[0029] To make the technical solution and advantages of the present invention clearer, the following description is provided in conjunction with the accompanying drawings and embodiments.

[0030] The present invention will be further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of protection of the present invention.

[0031] For the sake of brevity and intuitiveness, the following description uses several representative embodiments to illustrate the solution of the present invention. Numerous details in the embodiments are only used to aid in understanding the solution of the present invention. However, it is obvious that the technical solution of the present invention can be implemented without being limited to these details. To avoid unnecessarily obscuring the solution of the present invention, some embodiments are not described in detail, but only a framework is given. In the following text, "comprising" means "including but not limited to," and "according to..." means "at least according to..., but not limited to only according to...". Due to Chinese language habits, unless the quantity of a component is specifically indicated below, it means that the component can be one or more, or can be understood as at least one.

[0032] See Figure 1 As shown, the present invention provides an intelligent circuit breaker, including a circuit breaker control module and a tripping mechanism 40; the circuit breaker control module includes:

[0033] The sampling isolation circuit 10 includes a voltage acquisition isolation circuit 101 and a current acquisition circuit 102; the voltage acquisition isolation circuit 101 is used to acquire the voltage signal between the live wire L and the neutral wire N, the voltage signal between the live wire L and the ground wire PE, and the voltage signal between the neutral wire N and the ground wire PE, and is also used to isolate the line input terminal; the current acquisition circuit 102 is used to acquire the current signal of the ground wire PE;

[0034] The MCU controller 20 is connected to the sampling isolation circuit 10 and the tripping mechanism 40 respectively. It is used to determine whether the voltage signal and / or current signal reaches the protection threshold, and when the voltage signal and / or current signal reaches the protection threshold, it controls the tripping mechanism 40 to work, and the circuit breaker is tripped.

[0035] The back-end isolation circuit 30 is disposed between the MCU controller 20 and the tripping mechanism 40 to protect the MCU controller 20.

[0036] For details, see Figure 2As shown, the voltage acquisition isolation circuit 101 includes three voltage transformers (first voltage transformer T1, second voltage transformer T2, and third voltage transformer T3); the current acquisition circuit 102 includes a grounding current transformer CT1; the first voltage transformer T1 is used to acquire the voltage signal between the live wire L and the neutral wire N; the second voltage transformer T2 is used to acquire the voltage signal between the live wire L and the ground wire PE; the third voltage transformer T3 is used to acquire the voltage signal between the neutral wire N and the ground wire PE; and the grounding current transformer CT1 is used to acquire the current signal of the ground wire PE.

[0037] Furthermore, sampling resistors (R1, R2) are connected in series between the primary winding of the first voltage transformer T1 and the live wire L and the neutral wire N; sampling resistors (R4, R5) are connected in series between the primary winding of the second voltage transformer T2 and the live wire L and the ground wire PE; and sampling resistors (R7, R8) are connected in series between the primary winding of the third voltage transformer T3 and the neutral wire N and the ground wire PE. It should be noted that... Figure 2 The resistors shown are only one example; the specific number and value of resistors can be set according to actual needs. Correspondingly, a third resistor R3 is connected in parallel on the secondary winding side of the first voltage transformer T1; a sixth resistor R6 is connected in parallel on the secondary winding side of the second voltage transformer T2; and a ninth resistor R9 is connected in parallel on the secondary winding side of the first voltage transformer T1. A tenth resistor R10 is connected in parallel on the secondary winding side of the grounding current transformer CT1.

[0038] This embodiment samples the voltage values ​​between the live wire and neutral wire, the live wire and ground wire, and the ground wire and neutral wire using voltage transformers, and collects the current signal of the ground wire PE using a ground current transformer CT1 (GCT). This allows for comprehensive acquisition and monitoring of over / under voltage signals and current signals from the smart circuit breaker, providing all-around protection against lightning strikes for downstream equipment. Furthermore, the voltage transformers act as front-end isolation, isolating the MCU controller 20 from the front-end circuitry without affecting signal input.

[0039] It should be noted that the voltage transformer can be replaced by a voltage transformer, and the current transformer CT1 can be replaced by a current transformer.

[0040] Furthermore, to further protect the MCU controller 20, the sampling isolation circuit 10 also includes four diodes; one diode is provided between each voltage transformer and the MCU controller 20; and one diode is provided between the grounding current transformer CT1 and the MCU controller 20.

[0041] In this embodiment, the diode is a bidirectional diode. A bidirectional diode has a voltage-regulating effect in both forward and reverse directions, just like two Zener diodes connected in reverse series. No matter which direction it is in, once the reverse breakdown voltage of the stable voltage (i.e., that of one of the Zener diodes) is reached, the voltage across its terminals can remain basically unchanged (within its allowable current range).

[0042] Specifically, the third resistor R3 is connected in parallel with the first bidirectional diode D1, the sixth resistor R6 is connected in parallel with the second bidirectional diode D2, the ninth resistor R9 is connected in parallel with the third bidirectional diode D3, and the tenth resistor R10 is connected in parallel with the fourth bidirectional diode D4.

[0043] The sampling isolation circuit 10 also includes four capacitors; one capacitor is provided between each voltage transformer and the MCU controller 20; one capacitor is provided between the grounding current transformer CT1 and the MCU controller 20, and the capacitors can play the role of isolation and filtering.

[0044] Specifically, the third resistor R3 is connected in parallel with the first capacitor C1, the sixth resistor R6 is connected in parallel with the second capacitor C2, the ninth resistor R9 is connected in parallel with the third capacitor C3, and the tenth resistor R10 is connected in parallel with the fourth capacitor C4.

[0045] In this embodiment, the back-end isolation circuit 30 includes a capacitor isolation chip U3. The capacitor isolation chip U3 is model π161U31. Using the capacitor isolation chip U3 is less expensive than using an optocoupler isolation chip.

[0046] In conjunction with the aforementioned front-end isolation, this embodiment uses a voltage transformer with isolation function at the input end to isolate it from the front-end line without affecting the signal input. At the back end, a back-end isolation circuit 30 is used to isolate the MCU controller 20 from the back-end tripping mechanism 40, the electric operating mechanism 50, and the communication module 60, etc. The back-end isolation circuit 30 uses a low-cost capacitor isolation chip U3. The front-end and back-end isolation scheme of this embodiment ensures that the MCU controller 20 is relatively independent and is therefore unaffected by the electromagnetic radiation from lightning strikes at the front and back ends. In other words, even during a lightning strike, the MCU controller 20 can still operate normally without being affected, thereby ensuring that the intelligent circuit breaker is always under control and protecting the customer's back-end equipment.

[0047] Furthermore, the circuit breaker control module also includes a communication module 60; the communication module 60 is connected to the MCU controller 20 and the host computer 70 respectively, and is used to realize bidirectional communication between the MCU controller 20 and the host computer 70. The communication module 60 includes a serial communication module 60 and / or a network communication module 60.

[0048] In this embodiment, the communication module 60 is an RS485 communication module 60. That is, the intelligent circuit breaker in this embodiment communicates with the host computer 70 via an RS485 bus. The MCU controller 20 can upload the opening and closing information of the intelligent circuit breaker and information such as lightning strike faults to the host computer 70 via the RS485 bus, and the host computer 70 can monitor the operating status of the circuit breaker, thereby facilitating remote self-diagnosis by the customer; in addition, remote control of opening and closing can also be realized through the host computer 70.

[0049] Furthermore, the circuit breaker control module also includes an energy metering chip U1; the energy metering chip U1 is disposed between the sampling isolation circuit 10 and the MCU controller 20. The energy metering chip U1 is used for signal conditioning and A / D conversion. It should be noted that the function of the energy metering chip U1 can also be integrated into the MCU processor.

[0050] Furthermore, the intelligent circuit breaker also includes an electric operating mechanism 50; the MCU controller 20 is connected to the electric operating mechanism 50 to control the operation of the electric operating mechanism 50, and the circuit breaker realizes opening / closing.

[0051] In this embodiment, the tripping mechanism 40 includes a tripping coil drive module and a tripping coil. The electric operating mechanism 50 includes a circuit breaker drive module and an electric operating actuator.

[0052] See Figure 3 As shown, the MCU controller 20 judges the voltage signals between the live wire L and the neutral wire N, the voltage signals between the live wire L and the ground wire PE, the voltage signals between the neutral wire N and the ground wire PE, and the current signal of the ground wire PE, which are collected in real time. When any of them exceeds the protection threshold (the protection thresholds for the voltage signals between the live wire L and the neutral wire N, the voltage signals between the live wire L and the ground wire PE, the voltage signals between the neutral wire N and the ground wire PE, and the current signal of the ground wire PE are all different, or the voltage signals between the live wire L and the neutral wire N, the voltage signals between the live wire L and the ground wire PE, and the voltage signals between the neutral wire N and the ground wire PE are set to be the same), it sends a command to the trip coil drive module to control the trip coil to trip quickly, thereby protecting the smart circuit breaker itself and the downstream equipment.

[0053] The electric operating mechanism 50 in this embodiment can be remotely controlled to meet the customer's remote control requirements for opening and closing the circuit breaker. Specifically, the electric operating mechanism 50 is located within the intelligent electric operating control pole, and the tripping mechanism 40 is located within the neutral (N) pole.

[0054] See Figure 4As shown, in this embodiment, the voltage / current signal acquisition time can be controlled to around 40ms, the processing time of the power metering chip U1 and the MCU controller 20 is around 15ms, and the tripping time of the tripping coil is around 3ms. Therefore, the intelligent circuit breaker can be quickly tripped within 60ms after a lightning strike, thereby quickly protecting the downstream equipment. Furthermore, the overvoltage value in this embodiment can reach up to 1000V, and even at an overvoltage value as high as 1000V, the intelligent circuit breaker can still be quickly tripped within 60ms. This not only protects the intelligent circuit breaker itself but also further protects the downstream equipment (because the downstream equipment has certain requirements for withstand voltage and the time it can withstand at a certain withstand voltage; exceeding a certain withstand voltage or exceeding the time it can withstand at a certain withstand voltage will damage the equipment, so rapid tripping is necessary).

[0055] The above are merely specific embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be considered as infringing upon the protection scope of the present invention.

Claims

1. An intelligent circuit breaker comprising a circuit breaker control module and a back end device; the back end device comprising a tripping mechanism, a communication module and an electric operating mechanism; characterized in that, The MCU controller is not affected by electromagnetic radiation caused by lightning, so that the intelligent circuit breaker is still in a controlled state when the overvoltage value exceeds 1000V, and the rear-end equipment of the intelligent circuit breaker is protected. The sampling isolation circuit includes a voltage sampling isolation circuit and a current sampling circuit; the voltage sampling isolation circuit is used for sampling voltage signals between a live wire L and a zero wire N, between the live wire L and a ground wire PE, and between the zero wire N and the ground wire PE, and is also used for isolating a line input end; the current sampling circuit is used for sampling a current signal of the ground wire PE; The MCU controller is connected with the sampling isolation circuit and the tripping mechanism respectively, is used for judging whether the voltage signal and / or the current signal reaches a protection threshold, and controls the tripping mechanism to work when the voltage signal and / or the current signal reaches the protection threshold, so that the circuit breaker realizes opening; the communication module is connected with the MCU controller and an upper computer respectively, and is used for realizing bidirectional communication between the MCU controller and the upper computer; the MCU controller is connected with the electric operating mechanism to control the electric operating mechanism to work, so that the circuit breaker realizes opening / closing; The rear-end isolation circuit is arranged between the MCU controller and the tripping mechanism, the communication module and the electric operating mechanism, and is used for protecting the MCU controller; the rear-end isolation circuit includes a capacitor isolation chip; The voltage sampling isolation circuit includes three voltage transformers; the current sampling circuit includes a grounding current transformer; the three voltage transformers are respectively used for sampling voltage signals between the live wire L and the zero wire N, between the live wire L and the ground wire PE, and between the zero wire N and the ground wire PE; and the grounding current transformer is used for sampling the current signal of the ground wire PE.

2. The intelligent circuit breaker of claim 1, wherein, The sampling isolation circuit further includes four diodes; one diode is arranged between each voltage transformer and the MCU controller; and one diode is arranged between the grounding current transformer and the MCU controller.

3. The intelligent circuit breaker of claim 2, wherein, The diodes are bidirectional diodes.

4. The intelligent circuit breaker of claim 1, wherein, The sampling isolation circuit further includes four capacitors; one capacitor is arranged between each voltage transformer and the MCU controller; and one capacitor is arranged between the grounding current transformer and the MCU controller.

5. The intelligent circuit breaker of claim 1, wherein, The communication module includes a serial communication module and / or a network communication module.

6. The intelligent circuit breaker of claim 1, wherein, The circuit breaker control module further includes an electric energy metering chip; the electric energy metering chip is arranged between the sampling isolation circuit and the MCU controller.

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