阅读说明：本技术 一种直流微型断路器 (DC miniature circuit breaker ) 是由 朱金保 董郁 刘万里 邓艺军 李阳 李虎 南添 南寅 于 2020-05-22 设计创作，主要内容包括：本发明提供了一种直流微型断路器,包括绝缘外壳、进线端子、静触头、动触头、操作机构、执行器、出线端子、锰铜电阻、电压采集器、电子控制器,所述电子控制器包括第一微处理器、第二微处理器,所述锰铜电阻串联接入主电路。可以实现短路保护、过欠压保护、剩余电流监测、计量功能、自动物理拓扑支持、就地故障研判、HPLC通信、线损分析支持、电弧保护等功能。还包括磁调制式直流剩余电流互感器,实现直流剩余电流监测与保护功能。(The invention provides a direct-current miniature circuit breaker which comprises an insulating shell, an incoming line terminal, a fixed contact, a movable contact, an operating mechanism, an actuator, an outgoing line terminal, a manganin resistor, a voltage collector and an electronic controller, wherein the electronic controller comprises a first microprocessor and a second microprocessor, and the manganin resistor is connected in series with a main circuit. The functions of short-circuit protection, over-voltage and under-voltage protection, residual current monitoring, metering function, automatic physical topology support, on-site fault study and judgment, HPLC communication, line loss analysis support, arc protection and the like can be realized. The magnetic modulation type direct current residual current transformer is further included, and the direct current residual current monitoring and protecting functions are achieved.)

1. A direct current miniature circuit breaker comprising: at least one insulating housing (9), at least one inlet terminal (10), at least one static contact (11), at least one moving contact (12), at least one operating device (13), at least one executor (14), at least one outlet terminal (15), at least one manganin resistance (16), at least one voltage collector (25), at least one electronic controller (17), its characterized in that:

the electronic controller (17) comprises a first microprocessor (17-8) and a second microprocessor (17-9);

the manganin resistor (16) is arranged at the positive pole and/or the negative pole of the main circuit of the direct current miniature circuit breaker and is used as the energy input of a current collector metered by the electronic controller (17) and/or a current collector for overcurrent protection measurement and/or a current collector at a high-frequency megahertz level and/or a current self-generating power supply when the load end of the miniature circuit breaker is short-circuited.

2. The dc miniature circuit breaker of claim 1, wherein: the manganin resistor (16) bears i of the limit short-circuit breaking current of the miniature circuit breaker²t no melting.

3. The dc miniature circuit breaker of claim 1, wherein: when the temperature of the manganin resistor (16) changes +/-60 ℃, the resistance change rate is not more than 0.5%.

4. The dc miniature circuit breaker of claim 1, wherein: the manganin resistor (16) comprises an upper end (16-1) and a lower end (16-2), current analog signals sampled by the upper end (16-1) and the lower end (16-2) and positive and negative voltage signals (17-U) are respectively transmitted to the electronic controller (17), and the electronic controller (17) performs over-current protection judgment and driving control on electric quantity metering and rated current of at least 4 times of rated current of the circuit breaker.

5. The dc miniature circuit breaker of claim 1, wherein: the magnetic trip (18) is used for driving the operating mechanism (13) to act and realizing short circuit instantaneous protection.

6. The direct current miniature circuit breaker according to claim 4, wherein: the thermal trip unit (19) is included, and the thermal trip unit (19) drives the operating mechanism (13) to act and realizes overload long-time delay protection.

7. The dc miniature circuit breaker of claim 3, wherein: the electronic controller (17) comprises a driving circuit (17-2), and the driving circuit (17-2) is electrically connected with the magnetic flux converter (14) and drives the magnetic flux converter (14) to drive the operating mechanism (13) to open.

8. The dc miniature circuit breaker of claim 7, wherein: the device also comprises a micro direct current motor (26), wherein the micro direct current motor (26) is electrically connected with the driving circuit (17-2) and is transmitted through a speed reducer (23) to drive the operating mechanism (13) to close.

9. The dc miniature circuit breaker of claim 1, wherein: the electronic controller (17) includes an isolated power module (17-1).

10. The dc miniature circuit breaker of claim 9, wherein: the isolation power supply module (17-1) is taken from a voltage and/or current self-generating power supply and current signal sampling circuit (17-3).

11. The dc miniature circuit breaker of claim 1, wherein: the magnetic modulation type direct current residual current transformer (21) is further included, and the magnetic modulation type direct current residual current transformer (21) penetrates through the positive and negative conductors of the main circuit at the same time.

12. The dc miniature circuit breaker of claim 1, wherein: also comprises a temperature collector (22).

13. The dc miniature circuit breaker of claim 1, wherein: the wireless communication system comprises a communication module (20), wherein the communication module (20) adopts a wireless communication mode and/or a wired communication mode, the wireless communication mode comprises at least one of communication modes such as 4G, 5G, WIFI, BLE, ZigBee, NB-IoT and LoRa, and the wired communication mode comprises at least one of communication modes such as HPLC, PLC, RS485, LAN, CAN, DeviceNet and Profibus.

14. The dc miniature circuit breaker of claim 1, wherein: the system comprises a human-computer interaction module (24), wherein the human-computer interaction module (24) comprises a metering pulse lamp.

Technical Field

The invention relates to a direct current miniature circuit breaker, belonging to the field of low-voltage electrical appliances.

Background

With the continuous promotion of national grid ubiquitous power internet of things plans, each product in the electric power system is constantly transformed and upgraded, communication modules such as carrier wave, bluetooth, etc., electronic controller, data display, etc. are added in the circuit breaker, the normal work of each module depends on stable power, corresponding national standard also stipulates that the electronic controller of low-voltage circuit breaker should have at least one by the self-generating power of protected circuit energy production to obtain stable output voltage. When an electronic controller in the circuit breaker normally works, the system disturbance problems need to be overcome, such as disturbance caused by power supply load power change, starting and stopping of electric appliances in a power grid, even current change caused by faults and the like.

In addition, when the module is more in the circuit breaker, can lead to the inner space crowded, be unfavorable for the reasonable overall arrangement of product inner structure, especially when there are a plurality of voltage collectors and current collector inside the circuit breaker. Based on the problems, the internal structures of the product need to be optimally designed, the volume minimization is realized, more internal spaces are provided for upgrading other intelligent functions, and the intelligent and internet-of-things trend of the electric appliance is adapted; meanwhile, the product design is carried out at a cost acceptable in the market in consideration of the cost.

Thirdly, the novel circuit breaker needs to realize the functions of current measurement, overload protection, short circuit short delay protection, short circuit instantaneous protection, ground fault protection and the like, so that the current collector, the voltage collector and the like are required to have the functions of metering and self-generating power supply, and the current collector, the voltage collector and the like need to be reasonably designed for realizing the functions.

Disclosure of Invention

Based on the above background, the present invention provides a dc miniature circuit breaker, which can effectively overcome the above problems.

The technical scheme of the invention is as follows:

a direct current miniature circuit breaker comprising: at least one insulating shell, at least one incoming line terminal, at least one static contact, at least one moving contact, at least one operating mechanism, at least one actuator, at least one outgoing line terminal, at least one manganin resistor, at least one voltage collector and at least one electronic controller,

the electronic controller comprises a first microprocessor and a second microprocessor;

the manganin resistor is arranged at the positive pole and/or the negative pole of the main circuit of the direct current miniature circuit breaker and is used as the energy input of a current collector metered by the electronic controller and/or a current collector measured by overcurrent protection and/or a current collector at a high-frequency megahertz level and/or a current self-generating power supply when the load end of the miniature circuit breaker is short-circuited.

Preferably, the manganin resistor bears i of the limit short-circuit breaking current of the miniature circuit breaker²t no melting.

Preferably, the manganese copper resistor has a resistance change rate of not more than 0.5% when the temperature changes +/-60 ℃.

Preferably, the manganin resistor comprises an upper end and a lower end, current analog signals sampled by the upper end and the lower end and voltage signals of a positive electrode and a negative electrode are respectively transmitted to the electronic controller, and the electronic controller performs over-current protection judgment and driving control on electric quantity metering and rated current of at least 4 times of rated current of the circuit breaker.

Preferably, the direct current miniature circuit breaker comprises a magnetic release, and the magnetic release drives the operating mechanism to act and realize short circuit instantaneous protection.

Preferably, the direct-current miniature circuit breaker comprises a thermal release, and the thermal release drives the operating mechanism to act and realize overload long-time delay protection.

Preferably, the electronic controller includes a driving circuit, and the driving circuit is electrically connected to the magnetic flux converter and drives the magnetic flux converter to drive the operating mechanism to open.

Preferably, the dc miniature circuit breaker further comprises a miniature dc motor, and the miniature dc motor is electrically connected to the driving circuit and is transmitted through a speed reducer to drive the operating mechanism to close.

Preferably, the electronic controller comprises an isolated power supply module.

Preferably, the isolation power supply module is taken from a voltage and/or current self-generating power supply and a current signal sampling circuit.

Preferably, the direct current miniature circuit breaker further comprises a magnetic modulation type direct current residual current transformer, and the magnetic modulation type direct current residual current transformer penetrates through a positive conductor and a negative conductor of the main circuit at the same time.

Preferably, the dc miniature circuit breaker further comprises a temperature collector.

Preferably, the dc miniature circuit breaker includes a communication module, the communication module adopts wireless communication and/or wired communication mode, the wireless communication includes at least one of communication modes such as 4G, 5G, WIFI, BLE, ZigBee, NB-IoT and LoRa, and the wired communication includes at least one of communication modes such as HPLC, PLC, RS485, LAN, CAN, DeviceNet and Profibus.

Preferably, the direct current miniature circuit breaker comprises a human-computer interaction module, and the human-computer interaction module comprises a metering pulse lamp.

The invention has the following beneficial effects:

1. the invention provides a direct-current miniature circuit breaker which comprises an insulating shell, an incoming line terminal, a fixed contact, a movable contact, an operating mechanism, a magnetic flux converter, an outgoing line terminal, a manganin resistor, a voltage collector and an electronic controller, wherein the electronic controller comprises a first microprocessor and a second microprocessor, and the manganin resistor is connected in series with a main circuit. The functions of short-circuit protection, over-voltage and under-voltage protection, residual current monitoring, metering function, automatic physical topology support, on-site fault study and judgment, HPLC communication, line loss analysis support, arc protection and the like can be realized.

2. The insulating shell is provided with the light pulse output display lamp, so that the light pulse output can be monitored and displayed, and the insulating shell has various shapes and can be adjusted according to different switches.

3. The temperature collector is arranged in the insulating shell, is one of a thermocouple, a thermistor, a platinum resistor and a temperature IC, and can realize early warning and alarming of temperature abnormity caused by wiring faults.

4. The invention is provided with a communication module, a microprocessor is connected with the communication module, the microprocessor receives/sends communication data through the communication module, carries out operations such as calibration, reporting, setting and the like according to an instruction analyzed by the received communication data, and then sends an operation result, thereby realizing a communication function. And the communication module adopts a wireless communication and/or wired communication mode, and the communication mode of the monitor is various, so that more selection spaces are provided for users.

5. The invention realizes the function of high-precision direct current measurement in an ultra-wide temperature range from minus 40 ℃ to 80 ℃ by arranging at least one manganin resistor with a first-order resistance temperature coefficient not greater than +10 and a second-order resistance temperature coefficient not less than minus 0.25.

6. The invention also comprises a magnetic modulation type direct current residual current transformer which can realize the functions of monitoring and protecting the direct current residual current.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic diagram of an embodiment of a dc miniature circuit breaker according to the present invention.

Fig. 2 is a schematic diagram of another embodiment of a dc miniature circuit breaker according to the present invention.

Fig. 3 is a schematic diagram of another embodiment of a dc miniature circuit breaker according to the present invention.

Fig. 4 is a schematic diagram of a dc miniature circuit breaker according to another embodiment of the present invention.

Fig. 5 is a structural diagram of a dc miniature circuit breaker according to the present invention.

Detailed Description

Features and exemplary embodiments of various aspects of the present invention will be described in detail below. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the present invention. The present invention is in no way limited to any specific configuration and algorithm set forth below, but rather covers any modification, replacement or improvement of elements, components or algorithms without departing from the spirit of the invention.

As shown in fig. 1 and 5, the present embodiment discloses a dc miniature circuit breaker, which includes: the magnetic flux transformer comprises at least one insulating shell 9, at least one incoming line terminal 10, at least one fixed contact 11, at least one movable contact 12, at least one operating mechanism 13, at least one magnetic flux converter 14, at least one outgoing line terminal 15, at least one manganin resistor 16, at least one voltage collector 25 and at least one electronic controller 17, wherein the fixed contact 11, the movable contact 12, the operating mechanism 13, the actuator 14, the outgoing line terminal 15, the manganin resistor 16, the voltage collector 25 and the electronic controller 17 are arranged in the insulating shell 9.

The moving contact 12 is controlled by the operating mechanism 13, and under the driving of the operating mechanism 13, the moving contact 12 can be in contact with or separated from the fixed contact 11, so that the switching-on or switching-off of the direct-current miniature circuit breaker is realized.

The operating mechanism 13 is provided with a handle, the handle is operated by hands to realize manual opening and closing of the circuit breaker, meanwhile, the operating mechanism 13 is further provided with a trip rod, and the trip rod is acted by the magnetic flux converter 14 to realize opening of the circuit breaker. Further, a handle of the operating mechanism 13 is provided with a transmission gear, at this time, an electric operating mechanism is further arranged in the dc miniature circuit breaker, the electric operating mechanism includes a miniature dc motor 26, the miniature dc motor 26 is electrically connected with a driving circuit 17-2 of the electronic controller 17, the driving circuit 17-2 can provide a driving signal for the miniature dc motor 26, the miniature dc motor 26 is transmitted through a speed reducer 23 to drive the operating mechanism 13 to be closed, and the transmission gear on the handle is acted by the speed reducer 23 driven by the miniature dc motor 26, so that the automatic closing of the miniature dc circuit breaker can be realized.

The actuator 14 provides a tripping force for the operating mechanism 13 when the dc miniature circuit breaker has fault currents such as overload and short circuit, the operating mechanism 13 trips under the action of the tripping force and drives the moving contact 12 to be separated from the static contact 11, so that the dc miniature circuit breaker is disconnected and electrical safety is ensured, the wire inlet end 10 and the wire outlet end 15 are respectively arranged at two ends of the insulating housing 19 and are respectively connected with an output end of a superior electrical appliance and an inferior electrical unit, namely, the wire inlet end 10 and the wire outlet end 15 are used for connecting a conductive wire so as to be electrically connected to a power supply and a load. The actuator 14 may be one or more of a magnetic flux converter, an electromagnet, and a shunt release, and in this embodiment, the actuator 14 is a magnetic flux converter.

The electronic controller 17 comprises an isolation power supply module 17-1, a driving circuit 17-2, a current self-generating power supply and current signal sampling circuit 17-3, a voltage signal sampling circuit 17-4, a voltage signal processing circuit 17-5, a first microprocessor 17-8 and a second microprocessor 17-9, wherein the isolation power supply module 17-1 is obtained from the voltage and/or current self-generating power supply and current signal sampling circuit 17-3, and is electrically connected with and drives the magnetic flux converter 14 through the driving circuit 17-2 so as to drive the operating mechanism 13 to be switched off. The magnetic flux converter 14 acts and further acts on the trip bar to realize the opening of the circuit breaker, and further realize the remote opening function.

In a preferred embodiment, the dc miniature circuit breaker includes a magnetic trip 18, which is configured to meet the transient short circuit action, and drives the operating mechanism 13 to act, so as to trip the circuit breaker, thereby realizing the transient short circuit protection. The short circuit transient protection realized by the magnetic trip 18 is a backup protection scheme of short circuit transient protection realized by other electronic components such as the manganin resistor 16 and the like. By the arrangement, the reliability of short-circuit protection of the direct-current miniature circuit breaker is further improved by a scheme of redundancy design and parallelism.

In a preferred embodiment, the dc miniature circuit breaker further comprises a thermal release 19 configured to satisfy the overload long-delay action, and drive the operating mechanism 13 to act, so as to release the circuit breaker, thereby implementing the overload long-delay protection. In this embodiment, the metering is realized by the description of the dc metering function, and the overload protection and the short-circuit protection of the overcurrent protection are realized by the thermal release 19 and the magnetic release 18, respectively. The advantages of this arrangement are: the current metering range is smaller, the requirement for subsequent electronic components such as an ADC circuit in the first microprocessor 17-8 or an ADC circuit arranged outside the first microprocessor 17-8 is low in digit, and high-precision and low-cost metering is easy to realize.

In a preferred embodiment, the dc miniature circuit breaker further includes a communication module 20, the communication module 20 adopts a wireless communication mode and/or a wired communication mode, the wireless communication mode includes at least one of communication modes such as 4G, 5G, WIFI, BLE, ZigBee, NB-IoT and LoRa, and the wired communication mode includes at least one of communication modes such as HPLC, PLC, RS485, LAN, CAN, DeviceNet and Profibus.

In a preferred embodiment, the dc miniature circuit breaker includes a human-computer interaction module 24, and the human-computer interaction module 24 includes a liquid crystal display, an audible and visual alarm device, a metering pulse calibration lamp, an infrared metering calibration interface, an input key, a test interface, a status display lamp, and the like. The metering pulse lamp is arranged in a visible area on the front surface of the miniature circuit breaker and is used for providing a convenient interface during maintenance, calibration and metering functions.

In a preferred embodiment, the dc miniature circuit breaker further includes a temperature collector 22, and the temperature collector 22 is one of a thermocouple, a thermistor, a platinum resistor, and a temperature IC. The temperature collector 22 can collect the temperature of the incoming terminal 10 and/or the outgoing terminal 15 of the direct current miniature circuit breaker and/or the temperature near the key electrical contact point in the circuit breaker, and transmit the collected temperature signal to the second microprocessor 17-9, and the second microprocessor 17-9 compares the internal firmware thereof with a preset temperature early warning/protection threshold value to obtain whether to perform temperature early warning/protection. If the temperature early warning is carried out, the early warning information is transmitted to the human-computer interaction module 24 for carrying out local temperature early warning and display and/or transmitted to the communication module 20 for carrying out remote temperature early warning; if the temperature protection action is carried out, the driving circuit 17-2 is driven, the driving circuit 17-2 further drives the magnetic flux converter 14 to act, the action is further carried out on the trip rod, the opening of the circuit breaker is realized, and the temperature protection function is further realized.

In a preferred embodiment, as shown in fig. 3, the dc miniature circuit breaker further includes a magnetic modulation type dc residual current transformer 21, at this time, the electronic controller 17 further includes a residual current signal conditioning circuit 17-10, the magnetic modulation type residual current transformer 21 simultaneously penetrates through the positive and negative conductors of the main circuit and collects residual current information of the main circuit, and the magnetic modulation type dc residual current transformer 21 receives a magnetic modulation signal of the residual current signal conditioning circuit 17-10 of the electronic controller 17 and outputs an induction output signal thereof. When a direct current residual current occurs to the anode or the cathode in the main circuit, the output sensing output signal changes, the changed output signal is received and conditioned by the residual current signal conditioning circuit 17-10 and then transmitted to the second microprocessor 17-9, the second microprocessor 17-9 obtains the value of the direct current residual current according to the internal firmware algorithm of the second microprocessor, and compares the value with the preset residual current protection threshold value to obtain whether the residual current protection action is performed or not. If the residual current protection action is carried out, the driving circuit 17-2 is driven, the driving circuit 17-2 further drives the magnetic flux converter 14 to act, the action is further carried out on the trip rod, the brake opening of the circuit breaker is realized, and the direct current residual current protection function is further realized.

The manganin resistor 16 comprises an upper end 16-1 and a lower end 16-2, the upper end 16-1 and the lower end 16-2 are respectively and oppositely arranged at two ends of the manganin resistor 16, current analog signals sampled by the upper end 16-1 and the lower end 16-2 and positive and negative voltage signals 17-U are transmitted to the electronic controller 17, and the electronic controller 17 performs electric quantity metering and overcurrent protection judgment and drive control of rated current of at least 4 times of the rated current of the circuit breaker. And the 4 times rated current of the circuit breaker is the lowest threshold value of possible actions of the short-circuit protection of the direct-current circuit breaker.

The manganin resistor 16 is arranged at the positive pole or the negative pole of the direct current main circuit, and when the manganin resistor 16 is in a plurality, the manganin resistor can be respectively arranged at the positive pole and the negative pole of the direct current circuit breaker main circuit. The manganin resistor 16 can be used as a current collector for metering and overcurrent protection measurement of the electronic controller 17, namely, the voltage on the manganin resistor 16 is sampled, the current value flowing through the manganin resistor 16 is indirectly calculated according to the sampled voltage value and is provided for the electronic controller 17, the electronic controller 17 can receive current information transmitted by the manganin resistor 16, and the received current information can be used for one or more of metering, overcurrent protection measurement, fault arc monitoring and protection and a current self-generating power supply, namely: the manganin resistor 16 can be used as one or more functions of a current collector for metering, a current collector for overcurrent protection measurement, a current collector of high-frequency megahertz level and energy input of a current self-generating power supply when the load end of the miniature circuit breaker is in short circuit, of the electronic controller 17. The following detailed description is for each function:

in a preferred embodiment, the manganin resistor 16 has a direct current metering function, and specifically, as shown in fig. 1, the direct current miniature circuit breaker further includes a communication module 20 and a driving human-computer interaction module 24, the manganin resistor 16 includes an upper end 16-1 and a lower end 16-2, a current analog signal sampled by the upper end 16-1 and the lower end 16-2 is transmitted to a current self-generated power supply and current signal sampling circuit 17-3, the current self-generated power supply and current signal sampling circuit 17-3 samples a signal and transmits the signal to a current signal processing circuit 17-7, and the current signal processing circuit 17-7 processes the signal into a differential signal which can be received by a first microprocessor 17-8 and transmits the differential signal to the first microprocessor 17-8. Meanwhile, the voltage collector 25 collects the voltage between the positive electrode and the negative electrode of the direct-current miniature circuit breaker and transmits the voltage to the voltage signal sampling circuit 17-4, the voltage signal is sampled by the voltage signal sampling circuit 17-4 and then transmitted to the voltage signal processing circuit 17-5, and the voltage signal processing circuit 17-5 processes the sampled signal into a differential signal which can be received by the first microprocessor 17-8 and transmits the differential signal to the first microprocessor 17-8. After the voltage and current signals are calculated by the internal firmware of the first microprocessor 17-8, calculated values such as voltage, current, power, electricity amount and the like are obtained. The first microprocessor 17-8 is a metering chip or an SOC, when the first microprocessor 17-8 is a metering chip, the calculated values of the voltage, the current, the power, the electricity measurement and the like are transmitted to the second microprocessor 17-9, and the second microprocessor 17-9 is further communicated with the communication module 20 and drives the human-computer interaction module 24 to realize human-computer interaction such as display, calibration and the like. When the first microprocessor 17-8 is an SOC, the obtained calculated values of voltage, current, power, electricity metric and the like are transmitted to the second microprocessor 17-9, and are further communicated with the communication module 20 through the second microprocessor 17-9, and the obtained calculated values of voltage, current, power, electricity metric and the like are directly transmitted and drive the human-computer interaction module 24 to realize human-computer interaction such as display, calibration and the like. Furthermore, the direct current metering precision can be 0.5 level or 1 level by reasonably designing the current self-generating power supply and current signal sampling circuit 17-3, the current signal processing circuit 17-7, the voltage signal sampling circuit 17-4 and the voltage signal sampling circuit 17-4 in an anti-noise way and reasonably selecting the number of bits of an ADC in the first microprocessor 17-8.

The metering function comprises a freezing and recording function, such as daily freezing, and 62 daily freezing data can be recorded, wherein the data comprises daily freezing time, forward active total electric energy and reverse active total electric energy. And if the settlement date is settled, 12 settlement date data can be recorded, wherein the data comprises combined active total electric energy, forward active electric energy, reverse active total electric energy and reverse active electric energy. And storing for 40 days at a storage time interval of 1min as recorded by a load curve, wherein the storage time interval can be set. And event records, such as clock failure, power failure and the like.

In another preferred embodiment, the manganin resistor 16 has an overcurrent protection function and can be used as a current self-generating power supply of the electronic controller 17. Specifically, the overcurrent protection includes overload protection and short-circuit protection. When the current flowing through the direct-current miniature circuit breaker exceeds 1.13 times of the rated current of the direct-current miniature circuit breaker, the direct-current miniature circuit breaker is called overload current, and overload protection belongs to long-time delay protection. When overload current is generated in the direct current miniature circuit breaker, current analog signals sampled by the upper end 16-1 and the lower end 16-2 of the manganin resistor 16 are respectively transmitted to a current self-generating power supply and current signal sampling circuit 17-3, the current self-generating power supply and current signal sampling circuit 17-3 samples signals and transmits the signals to a current signal processing circuit 17-7, the current signal processing circuit 17-7 processes the signals into differential signals which can be received by a first microprocessor 17-8 and transmits the differential signals to the first microprocessor 17-8, the current signals are calculated by internal firmware of the first microprocessor 17-8 to obtain a calculated value such as current and then transmitted to a second microprocessor 17-9, and whether the calculated value exceeds or not is judged by a threshold value preset in the second microprocessor 17-9, if the current exceeds the preset value, the internal firmware of the second microprocessor 17-9 is executed, if the preset time is reached, the circuit 17-2 is driven, the magnetic flux converter 14 is further driven by the drive circuit 17-2 to act, the tripping rod is further acted, the opening of the circuit breaker is realized, and the overload protection is further realized. It should be noted that, in this embodiment, the power required by the current signal processing circuit 17-7, the first microprocessor 17-8, and the second microprocessor 17-9 is provided by the isolated power module 17-1, and the energy of the isolated power module 17-1 is taken from the voltage collector 25 and the current self-generated power and current signal sampling circuit 17-3.

Furthermore, the direct current miniature circuit breaker is divided into a B type and a C type, and corresponding short-circuit protection thresholds are different according to different types of the miniature circuit breaker, wherein the short-circuit protection threshold of the B type direct current miniature circuit breaker is 7 times of the rated current of the miniature circuit breaker, the short-circuit protection threshold of the C type direct current miniature circuit breaker is 15 times of the rated current of the miniature circuit breaker, and when the current exceeds 7 times (B type) or 15 times (C type) of the rated current of the miniature circuit breaker, the short-circuit current is judged. When short-circuit current is generated in the direct-current miniature circuit breaker, current analog signals sampled by the upper end 16-1 and the lower end 16-2 of the manganin resistor 16 are respectively transmitted to a current self-generating power supply and current signal sampling circuit 17-3, the current self-generating power supply and current signal sampling circuit 17-3 samples signals and then transmits the signals to a current signal processing circuit 17-7, and the current signal processing circuit 17-7 processes the signals into differential signals which can be received by a first microprocessor 17-8 and transmits the differential signals to the first microprocessor 17-8. The above current signal is calculated by the firmware inside the first microprocessor 17-8, and a calculated value such as current is obtained. And then the current is transmitted to a second microprocessor 17-9, whether the current exceeds the preset threshold value in the second processor 17-9 is judged, if the current exceeds the preset threshold value, internal firmware in the second microprocessor 17-9 is executed, if the preset threshold value reaches the preset time, a circuit 17-2 is driven, the drive circuit 17-2 further drives a magnetic flux converter 14 to act, the tripping lever is further acted, the tripping of the circuit breaker is realized, and further short-circuit or short-circuit short-delay protection is realized.

Further, in addition to the above short-circuit protection mode, short-circuit protection can be performed by another short-circuit protection mode, specifically, a current analog signal sampled by the upper end 16-1 and the lower end 16-2 of the manganin resistor 16 is transmitted to a current self-generating power supply and current signal sampling circuit 17-3, the current self-generating power supply and current signal sampling circuit 17-3 samples a signal and transmits the signal to a protection signal processing circuit 17-6, the protection signal processing circuit 17-6 performs signal processing and transmits the signal to a second microprocessor 17-9, whether the signal exceeds the threshold value preset in the second microprocessor 17-9 is determined, if the signal exceeds the threshold value, internal firmware of the second microprocessor 17-9 is executed, if the signal reaches a preset time, the circuit 17-2 is driven, and the driving circuit 17-2 further drives the magnetic flux converter 14 to operate, the breaker is further acted on the trip bar to realize the opening of the breaker, thereby realizing the rapid short-circuit protection. It should be noted that the power required by the current signal processing circuit 17-7, the first microprocessor 17-8, and the second microprocessor 17-9 is provided by the isolation power module 17-1, and the energy of the isolation power module 17-1 is obtained from the voltage collector 25 and the current self-generating power and current signal sampling circuit 17-3.

Description of the necessity of a current self-generating power supply: in a power electronic direct-current power supply and a direct-current storage battery, when the direct-current storage battery is in short circuit, voltage drops to a large extent, for example, the voltage drops to zero within 3ms in the power electronic power supply, the voltage also has the phenomenon when the direct-current storage battery is in short circuit, and the time for the voltage to drop to zero is different because the internal resistances of different types of storage batteries are different greatly and are dynamic. Therefore, in the case of overcurrent protection, it is necessary to provide a current self-generating power supply to ensure the reliability of the protection function.

The manganin resistor 16 is designed to bear the i of the limit short-circuit breaking current of the miniature circuit breaker²t is not melted, and considering the situation that a direct current miniature circuit breaker bears short circuit, the cross section of the manganin resistor 16 needs to be designed very carefully, and the requirement that the direct current miniature circuit breaker breaks the i in the whole process under the condition of extreme short circuit must be met²After t passes through the manganin resistor 16, the instantaneous energy is very large, so that the melting phenomenon is not required to occur.

The manganin resistor 16 is designed so that the resistance change rate does not exceed 0.5% when the temperature changes +/-60 ℃. The direct current electric energy meter is usually installed in an indoor environment, and the temperature change range is-5 ℃ to 40 ℃. The temperature change difference is small, and the requirement of the metering precision can be easily met in the temperature range. The installation environment of the circuit breaker is very harsh, and besides an indoor environment with good environmental conditions, the requirement of metering precision also needs to be met in an industrial environment and an outdoor environment. The temperature variation difference is large, from minus 40 ℃ to 80 ℃, and the temperature difference span is 120 ℃. Such a severe installation environment requires strict requirements for the first order resistance temperature coefficient and the second order resistance temperature coefficient of the manganin resistor 16 to meet the predetermined accuracy requirement. For example, if the 1-level metering accuracy in the full temperature range is met, the 1-level metering accuracy in the full temperature range can be met only if the change rate of the resistance value of the manganin resistor 16 is not more than 0.5% and the metering accuracy is verified to be at least 0.5% at normal temperature. Under the requirement, the first-order resistance temperature coefficient of the manganin resistor 16 is not more than +10, and the second-order resistance temperature coefficient is not less than-0.25.

In a preferred embodiment, as shown in fig. 4, the current signal collected by the manganin resistor 16 is used as a current collector in the high frequency megahertz level to realize the fault arc monitoring and protection functions. The current analog signals sampled by the upper end 16-1 and the lower end 16-2 of the manganin resistor 16 are transmitted to a current self-generating power supply and current signal sampling circuit 17-3, the current self-generating power supply and current signal sampling circuit 17-3 samples signals and then transmits the sampled signals to a current signal processing circuit 17-7, and the current signal processing circuit 17-7 processes the signals and transmits the processed signals to an internal or external memory of a second microprocessor 17-9. The second microprocessor 17-9 determines whether an arc exists according to its preset firmware by using characteristic values such as current mean value, current root mean square, frequency, harmonic and the like and a preset characteristic library. If the arc alarm is carried out, the alarm information is transmitted to the human-computer interaction module 24 for local arc alarm and display and/or transmitted to the communication module 20 for remote arc alarm; and if the arc protection action is carried out, the driving circuit 17-2 is driven, the driving circuit 17-2 further drives the magnetic flux converter 14 to act, the action is further carried out on the trip bar, the opening of the circuit breaker is realized, and the arc protection function is further realized. The feature library supports updates of the local feature library by the communication module 20.

Preferably, the direct-current miniature circuit breaker supports a remote control opening and closing function. When the communication module 20 receives a switching-off instruction of a superior device, the second microprocessor 17-9 collects voltage between the positive electrode and the negative electrode through the position switch linked with the operating mechanism 13 and the voltage collector 25, transmits the voltage to the voltage signal sampling circuit 17-4, samples the signal through the voltage signal sampling circuit 17-4 and transmits the signal to the voltage signal processing circuit 17-5, the voltage signal processing circuit 17-5 processes the sampled signal into a differential signal which can be received by the first microprocessor 17-8 and transmits the differential signal to the first microprocessor 17-8, and the voltage signal is calculated through the internal firmware of the first microprocessor 17-8 to obtain a calculated value such as voltage and then transmits the calculated value to the voltage information of the second microprocessor 17-9. The second microprocessor 17-9 performs firmware calculation according to the position switch information and the voltage information to obtain whether to drive the driving circuit 17-2, and the driving circuit 17-2 further drives the magnetic flux converter 14 to act, so as to further act on the trip bar, so that the opening of the circuit breaker is realized, and further, the remote opening function is realized. When the communication module 20 receives a switching-on instruction of a superior device, the second microprocessor 17-9 collects voltage between the positive electrode and the negative electrode through the position switch linked with the operating mechanism 13 and the voltage collector 25, transmits the voltage to the voltage signal sampling circuit 17-4, samples the signal through the voltage signal sampling circuit 17-4, transmits the signal to the voltage signal processing circuit 17-5, the voltage signal processing circuit 17-5 processes the sampled signal into a differential signal which can be received by the first microprocessor 17-8 and transmits the differential signal to the first microprocessor 17-8, and the voltage signal is calculated through the internal firmware of the first microprocessor 17-8 to obtain a calculated value such as voltage and then transmits the calculated value to the voltage information of the second microprocessor 17-9. The second microprocessor 17-9 performs firmware calculation according to the position switch information and the voltage information to determine whether to drive the driving circuit 17-2, the driving circuit 17-2 further drives the micro direct current motor 26, and then the micro direct current motor is transmitted through the speed reducer 23 to drive the operating mechanism 13 to be closed, so that a remote switching-on function is realized.

Preferably, the direct-current miniature circuit breaker supports a local control delay opening and closing function. The man-machine interaction module 24 receives manually set delay switching-off or delay switching-on information, the information is transmitted to the second microprocessor 17-9, the second microprocessor 17-9 performs firmware calculation according to the position switching information and the voltage information to obtain whether to drive the driving circuit 17-2, the driving circuit 17-2 further drives the magnetic flux converter 14 to act, and the magnetic flux converter further acts on a trip bar to realize switching-off of the circuit breaker, so that a remote switching-off function is realized; whether the driving circuit 17-2 is driven or not is obtained, the driving circuit 17-2 further drives the micro direct current motor 26, and then the micro direct current motor is transmitted through the speed reducer 23 to drive the operating mechanism 13 to be closed, so that a remote switching-on function is realized.

The remote control function of the direct-current miniature circuit breaker comprises an automatic mode and a manual mode, wherein the automatic mode is in a switching-off state when the circuit breaker is in the switching-on state, and the circuit breaker directly switches on the position after receiving a switching-on instruction. In the manual mode, when the breaker is in an opening state, a closing instruction is received, and the handle is used for completing closing without directly reclosing in place. Have timing switching on and off function, through the timing time of long-range setting, for example the time interval is in order to divide into unit, scope: 0-1439, sending 0 represents cutting off the time division/closing function. And automatically switching on/off after the set time is reached. With locking functions, such as remote locking: after the manual opening operation is executed, the remote control opening and closing function is automatically locked; and the manual closing is released.

Furthermore, the miniature circuit breaker has a fault studying and judging function and generates fault studying and judging information, for example, the miniature circuit breaker has the functions of judging events such as undervoltage, overvoltage, overcurrent, cutoff, power factor over-low limit, total power factor over-low limit, power flow reversal, active power reversal, overload, current loss, voltage loss, demand over-limit, power failure, incoming call, voltage reversal phase sequence, current reversal phase sequence and the like.

Furthermore, the miniature circuit breaker has a forced switching-on and switching-off function, and remote control switching-on/switching-off operation can be executed under the condition of remote control locking through an MODBUS-RTU extended command.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The present embodiments are to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.