A molded case circuit breaker

Abstract

This utility model discloses a molded case circuit breaker, including a housing and a main control module disposed within the housing. The housing also includes a controller plug-in accessory module, which comprises an LCD display interface, a status indicator interface, a function button interface, an external switch input interface, and a relay output interface. The controller plug-in accessory module is detachably connected to the corresponding I / O pins of the main control module via pin headers or terminal blocks. A remote communication control module and a voltage sampling display module are also disposed within the housing. This molded case circuit breaker adopts a modular plug-in design, allowing for detachable connection of accessories such as the LCD display, buttons, and indicator lights to the main control module via pin headers or terminal blocks, greatly improving the product's maintainability and functional expandability. The voltage sampling circuit employs a precision voltage divider and operational amplifier in-phase amplification conditioning circuit, combined with RC low-pass filtering, to support digital voltage display functionality and improve the accuracy of voltage sampling.

Description

Technical Field

[0001] This utility model relates to a molded case circuit breaker. Background Technology

[0002] With the rapid development of smart grids, molded case circuit breakers (MCCBs) are gradually evolving towards intelligence and networking. Existing intelligent MCCBs typically have functions such as remote opening and closing, and parameter monitoring. For example, the utility model disclosure CN207441619U discloses an MCCB controller, which includes a central processing unit (CPU), a current sampling circuit, a signal amplification circuit, an ADC conversion circuit, a BJ signal input module, an HZ signal output module, an FZ signal output module, a TTL conversion circuit, an RS485 communication circuit, a power amplification circuit, a tripping output circuit, a working status circuit, a power supply circuit, peripheral circuits of the CPU, and a function setting module. The current sampling circuit is connected to the input terminal of the ADC conversion circuit through the signal amplification circuit, and the output terminal of the ADC conversion circuit is connected to the current signal input terminal of the CPU. However, the following technical defects still exist in practical applications: 1. The human-machine interaction modules (such as displays, buttons, indicator lights, etc.) of traditional circuit breakers are mostly connected to the main control board by hard-wired soldering. Once damaged or when additional functional accessories are needed, the entire machine must be disassembled or even the main board replaced, resulting in extremely high maintenance costs and a lack of flexibility; 2. The working environment of circuit breakers is usually accompanied by severe conditions such as strong electrical interference and surges. If the existing remote communication interface lacks adequate electrical isolation and surge protection, it is very easy to cause the main control chip to crash or even burn out; 3. The voltage sampling circuit of existing circuit breakers has poor anti-interference capabilities, and firmware updates usually require professional personnel to disassemble the machine on-site for offline burning, which is time-consuming and labor-intensive. Utility Model Content

[0003] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a molded case circuit breaker to solve the technical problems of poor expandability of existing circuit breaker accessories, weak communication anti-interference capability, and difficulty in firmware upgrade.

[0004] To achieve the above objectives, this utility model provides a molded case circuit breaker, including a housing and a main control module disposed within the housing. The housing also includes a controller plug-in accessory module, which includes an LCD display interface, a status indicator interface, a function button interface, an external switch input interface, and a relay output interface. The controller plug-in accessory module is detachably plugged into the corresponding IO pins of the main control module via pin headers or terminal blocks. The housing also contains a remote communication control module and a voltage sampling and display module; The input terminal of the remote communication control module is used to connect to an external communication bus, and the output terminal is connected to the communication terminal of the main control module, for receiving remote control commands and sending them to the main control module; The input terminal of the voltage sampling and display module is used to connect to three-phase AC power, and the output terminal is connected to the analog-to-digital conversion pin of the main control module. It is used to condition the three-phase AC power signal and then input it to the main control module. The main control module is configured to calculate the effective value of the voltage based on the sampled signal and output it.

[0005] Preferably, the remote communication control module includes an RS-485 transceiver, an isolation circuit, and a surge protection circuit. The surge protection circuit is located at the access end of the external communication bus. The RS-485 transceiver is connected to the serial port pin of the main control module through the isolation circuit. The RS-485 transceiver is configured to convert the differential signal of the external communication bus into a TTL level signal and transmit it to the main control module after electrical isolation.

[0006] Preferably, the surge protection circuit includes a resettable fuse and a TVS transient voltage suppressor diode; the resettable fuse is connected in series in the power supply or signal circuit of the external communication bus, and the TVS transient voltage suppressor diode is connected in parallel between the signal terminal of the external communication bus and ground, for absorbing surge voltage.

[0007] Preferably, the voltage sampling and display module includes a voltage divider network, a bias reference circuit, a signal conditioning circuit, and a low-pass filter circuit; the three-phase AC power is attenuated by the voltage divider network, then a single-supply bias voltage is provided by the bias reference circuit, then proportionally amplified by the signal conditioning circuit, and finally filtered out by the low-pass filter circuit before being connected to the analog-to-digital conversion pin of the main control module.

[0008] Preferably, the signal conditioning circuit includes a multi-channel operational amplifier, which is configured as a non-inverting proportional amplifier circuit to adjust the attenuated voltage signal to the analog-to-digital conversion sampling range of the main control module; the main control module is configured to output the calculated effective voltage value to an external liquid crystal display module via an I2C bus.

[0009] Preferably, the housing also includes a program upgrade module, which is connected to the main control module and is used to send firmware data to the main control module to update the program of the main control module.

[0010] Preferably, the program upgrade module includes a local offline upgrade interface or a remote online upgrade channel implemented by the remote communication control module. The local offline upgrade interface includes an ISP download socket and a signal current limiting resistor. The ISP download socket is connected to the ISP download pin of the main control module through the signal current limiting resistor, and is used for an external downloader to write firmware to the main control module. The remote online upgrade channel is configured such that the main control module receives firmware data packets through the remote communication control module, caches them in internal memory or external storage chip, erases the original program and writes new firmware after verification.

[0011] Preferably, the ISP download pin of the main control module includes a program data pin and a download clock pin; the local offline upgrade interface also includes a reset pin, which is configured to be pulled low when the downloader is connected to trigger the main control module to enter the built-in ISP burning startup mode.

[0012] Preferably, in the remote online upgrade channel, the main control module is configured to perform CRC verification after receiving the complete firmware data packet, and after the verification is successful, switch to the firmware update partition, write the cached new firmware to the main program Flash area, and automatically restart to run the new version control program after the writing is completed.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. Modular plug-in design: The LCD screen, buttons, indicator lights and other accessories can be detachably connected to the main control module through pin headers or terminal blocks, which greatly improves the maintainability and functional expandability of the product.

[0014] II. High-Reliability Communication: Self-resetting fuses, TVS diodes, and isolation circuits are introduced at the front end of the RS-485 interface to effectively block surges and strong electrical interference in industrial environments, ensuring the safety of the main control chip.

[0015] III. High-precision sampling and dual upgrades: The system adopts a precision voltage divider and operational amplifier in-phase amplification conditioning circuit, combined with RC low-pass filtering, to improve the accuracy of voltage sampling; at the same time, it supports local ISP interface and remote 485 online upgrade (including CRC check and Flash partition management), which greatly reduces on-site operation and maintenance costs. Attached Figure Description

[0016] The present invention includes the following figures: Figure 1 This is a schematic diagram of the structure of a molded case circuit breaker provided by this utility model.

[0017] Figure 2 for Figure 1 A schematic diagram of the snap-fit ​​structure between the controller plug-in accessory module and the housing 1.

[0018] Figure 3 The present invention provides a circuit diagram of a molded case circuit breaker. Detailed Implementation

[0019] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended utility model purpose, the following detailed description of the specific implementation methods, structure, features and effects of this utility model is provided in conjunction with the accompanying drawings and preferred embodiments.

[0020] Reference Figure 1-3 As shown, this utility model provides a molded case circuit breaker, including a housing 1 and a main control module disposed within the housing 1. The housing 1 also includes a controller plug-in accessory module 2. (Refer to...) Figure 2 As shown, the controller plug-in accessory module 2 and the housing are respectively provided with a sliding groove 3 and a slider 4. The two sides of the frame of the sliding groove 3 have outward inclined grooves 5. The slider 4 has inclined surfaces 6 at both ends that match the inclined grooves 5. The slider 4 and the sliding groove 3 are plugged in to realize the snap-fit ​​of the controller plug-in accessory module 2 on the housing 1. The internal components of the two are connected by wires passing through the through holes at the mating surfaces of the two.

[0021] Reference Figure 1 , Figure 3 As shown, the controller plug-in accessory module 2 includes an LCD display interface, a status indicator interface, a function button interface, an external switch input interface, and a relay output interface. The controller plug-in accessory module 2 is detachably connected to the corresponding IO pins of the main control module via pin headers or terminal blocks. In this embodiment, the controller plug-in accessory module 2 includes an LCD2 LCD pin header (Header 8), 2*5P LED indicator terminals (H4), button terminals (H3), DIP switches (KEY1~KEY4), FL XH optocoupler input terminals (J7), and all external connectors for the opening / closing relay output terminals (JY2 / JY4). The LCD display connector, status LED external terminals, function button connectors, external switch input terminals, and opening / closing relay output terminals are all external accessory connectors for the main control MCU.

[0022] Reference Figure 3As shown, the housing also houses a remote communication control module and a voltage sampling and display module. The input terminal of the remote communication control module is connected to an external communication bus, and its output terminal is connected to the communication terminal of the main control module. It receives remote control commands and sends them to the main control module. The remote communication control module includes an RS-485 transceiver, an isolation circuit, and a surge protection circuit. The surge protection circuit is located at the access terminal of the external communication bus. The RS-485 transceiver is connected to the serial port pin of the main control module through the isolation circuit. The RS-485 transceiver is configured to convert the differential signal of the external communication bus into a TTL level signal and transmit it to the main control module after electrical isolation. The main control module is configured to, after parsing the remote control command, output a drive signal to control the operation of the circuit breaker's opening and closing relays, and upload field voltage, fault information, and opening / closing status to an external host computer through the remote communication control module.

[0023] The surge protection circuit described above includes a resettable fuse and a TVS transient voltage suppressor diode. The resettable fuse is connected in series in the power supply or signal circuit of the external communication bus, and the TVS transient voltage suppressor diode is connected in parallel between the signal terminal of the external communication bus and ground to absorb surge voltage.

[0024] The aforementioned remote communication control module includes a UT1 VP3082, three EL3H7 optocoupler isolation chips (OP3 / OP4 / OP5), a 485A / 485B bus terminal (JY3), current-limiting resistors (R20 / R22 / R25 / R26), a PTC006 resettable fuse, and a TVS surge protection circuit covering the entire area.

[0025] The above-mentioned remote communication control module works as follows: 1. Remote upper-level main control issues opening and closing commands and parameter configuration commands, which are connected to the JY3 terminal 485A / 485B via twisted-pair differential signals; II. PTC006, FS1 / FS2 current limiting + TVS diode to suppress bus surge and short-circuit high current; 3. The VP3082 completes the differential 485 level to MCU TTL level conversion, and the OP3 / OP4 / OP5 high-speed optocouplers isolate strong and weak currents to block strong electrical interference from entering the main control unit. 4. The isolated TXD / RXD signals are connected to the serial port pins of the STM32F103CBT6MCU. The MCU parses the remote instructions and outputs the output to drive the relay to complete the remote opening and closing control of the switch. At the same time, the field voltage, fault, and open / closed position status are uploaded to the remote master controller.

[0026] The input terminal of the voltage sampling and display module is used to connect to three-phase AC power, and the output terminal is connected to the analog-to-digital conversion pin of the main control module. It is used to condition the three-phase AC power signal before inputting it to the main control module. The main control module is configured to calculate the effective voltage value based on the sampled signal, output and display it. The voltage sampling and display module includes a voltage divider network, a bias reference circuit, a signal conditioning circuit, and a low-pass filter circuit. The three-phase AC power is attenuated by the voltage divider network, then a single-supply bias voltage is provided by the bias reference circuit, proportionally amplified by the signal conditioning circuit, and finally filtered by the low-pass filter circuit to remove high-frequency interference before being connected to the analog-to-digital conversion pin of the main control module. The signal conditioning circuit includes a multi-channel operational amplifier configured as a non-inverting proportional amplifier circuit to adjust the attenuated voltage signal to the sampling range of the analog-to-digital conversion of the main control module. The main control module is configured to output the calculated effective voltage value to an external liquid crystal display module via an I2C bus.

[0027] The voltage sampling and display module mentioned above includes: AC A / B / N three-phase voltage divider network Ra / Rab / Rb / Rn, U1A / U1B / U1C / U1D four-channel operational amplifiers, RC filters Caa / Cbb / Ccc, a reference 1.2V power supply Ver1.2V, and the complete circuit of the CS4 sampling output path.

[0028] The voltage sampling and display module described above operates as follows: 1. The three-phase AC A / AC B / AC N are divided by a 1.3M / 470K high-voltage precision resistor to attenuate the 380V high voltage to the safe low voltage range of the operational amplifier; 2. Ver1.2V provides a single-supply bias reference for the op-amps, and the four op-amps form a non-inverting amplification and conditioning circuit to match the MCU ADC sampling range of 0~3.3V; 3. Caa / Cbb / Cbb RC low-pass filter removes power grid harmonics and high-frequency interference; Fourth, the conditioned analog voltage is sent to the MCU ADC pin. The MCU software calculates the effective voltage value and outputs the voltage value to the LCD2 liquid crystal display module above through the I2C bus to realize local digital voltage display.

[0029] Reference Figure 3 As shown, a program upgrade module is also provided inside the housing. The program upgrade module is connected to the main control module and is used to send firmware data to the main control module to realize the program update of the main control module.

[0030] The program upgrade module includes a local offline upgrade interface or a remote online upgrade channel implemented through the remote communication control module. The local offline upgrade interface includes an ISP download socket and a signal current-limiting resistor. The ISP download socket is connected to the ISP download pin of the main control module through the signal current-limiting resistor, and is used for an external programmer to write firmware to the main control module. The remote online upgrade channel is configured such that the main control module receives firmware data packets through the remote communication control module, caches them in internal memory or an external storage chip, erases the original program and writes new firmware after successful verification. The ISP download pin of the main control module includes a program data pin and a download clock pin. The local offline upgrade interface also includes a reset pin, which is configured to be pulled low when a programmer is connected to trigger the main control module to enter the built-in ISP burning boot mode. In the remote online upgrade channel, the main control module is configured to perform CRC verification after receiving a complete firmware data packet. After successful verification, it switches to the firmware update partition, writes the cached new firmware to the main program Flash area, and automatically restarts to run the new version control program after writing is complete.

[0031] The aforementioned program upgrade module includes the following main core components: Connector terminal: B4B-XH-A ISP download socket. Signal current limiting resistors: RR2 (4.7K), RR3 (10K), main control chip: U1 HC32F105 MCU, signal pins: ICE_DATA (program data), ICE_CLK (download clock), auxiliary: 3.3V power supply, GND ground pin.

[0032] The local offline upgrade method is as follows (ISP burning method): 1. Connect the programmer cable to the onboard B4B-XH-A ISP connector. The programmer outputs 3.3V to power the MCU. 2. The programmer generates two signals: synchronous clock ICE_CLK and firmware data ICE_DATA. These signals are then sent to the HC32F105's built-in ISP download pin after being protected by RR2 / RR3 current limiting. 3. Hardware Reset: Pulling the REST pin low resets the MCU, and the chip enters the built-in ISP programming and boot mode; IV. The host computer programming software sends the new program firmware package frame by frame according to the HC32 serial port ISP protocol and writes it serially into the MCU's internal Flash via ICE_DATA; 5. After the firmware is fully transferred, the CRC will be automatically checked. If the check is successful, the downloader will be disconnected and the MCU will be reset to run the new version of the control program.

[0033] The remote online upgrade method is as follows (relying on the 485 remote control module): 1. The remote host computer sends out the complete firmware upgrade data package via the 485 bus (JY3 terminal, VP3082, isolation optocouplers OP3~OP5); 2. The MCU serial port receives all firmware and caches it in the on-chip RAM / external FM24W128 (UA2 memory chip). 3. After the data packet CRC check passes, the MCU switches to the firmware update partition to erase the original control program. 4. Write the new firmware cache to the main program Flash. After writing is complete, the system will automatically restart, thus completing the remote non-disassembly control system program upgrade.

[0034] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. The above preferred embodiments of the present utility model are not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of the present utility model. Any simple modifications, equivalent changes and alterations made by the technical essence of the present utility model to the above embodiments shall still fall within the scope of the technical solution of the present utility model.

Claims

1. A molded case circuit breaker, comprising a housing and a main control module disposed within the housing, characterized in that, The housing is also provided with a controller plug-in accessory module, which includes an LCD screen interface, a status indicator interface, a function button interface, an external switch input interface, and a relay output interface; the controller plug-in accessory module is detachably plugged into the corresponding IO pin of the main control module through pin headers or terminal blocks; The housing also contains a remote communication control module and a voltage sampling and display module; The input terminal of the remote communication control module is used to connect to an external communication bus, and the output terminal is connected to the communication terminal of the main control module, for receiving remote control commands and sending them to the main control module; The input terminal of the voltage sampling and display module is used to connect to three-phase AC power, and the output terminal is connected to the analog-to-digital conversion pin of the main control module. It is used to condition the three-phase AC power signal and then input it to the main control module. The main control module is configured to calculate the effective value of the voltage based on the sampled signal and output it.

2. A molded case circuit breaker according to claim 1, characterized in that, The remote communication control module includes an RS-485 transceiver, an isolation circuit, and a surge protection circuit. The surge protection circuit is located at the access end of the external communication bus. The RS-485 transceiver is connected to the serial port pin of the main control module through the isolation circuit. The RS-485 transceiver is configured to convert the differential signal of the external communication bus into a TTL level signal and transmit it to the main control module after electrical isolation.

3. A molded case circuit breaker according to claim 2, characterized in that, The surge protection circuit includes a resettable fuse and a TVS transient voltage suppressor diode; the resettable fuse is connected in series in the power supply or signal circuit of the external communication bus, and the TVS transient voltage suppressor diode is connected in parallel between the signal terminal of the external communication bus and ground to absorb surge voltage.

4. A molded case circuit breaker according to claim 1, characterized in that, The voltage sampling and display module includes a voltage divider network, a bias reference circuit, a signal conditioning circuit, and a low-pass filter circuit. The three-phase AC power is attenuated by the voltage divider network, then a single-supply bias voltage is provided by the bias reference circuit, amplified proportionally by the signal conditioning circuit, and finally filtered out by the low-pass filter circuit before being connected to the analog-to-digital conversion pin of the main control module.

5. A molded case circuit breaker according to claim 4, characterized in that, The signal conditioning circuit includes a multi-channel operational amplifier, which is configured as a non-inverting proportional amplifier circuit to adjust the attenuated voltage signal to the analog-to-digital conversion sampling range of the main control module; the main control module is configured to output the calculated effective voltage value to an external liquid crystal display module via an I2C bus.

6. A molded case circuit breaker according to claim 1, 2, 3, 4, or 5, characterized in that, The housing also contains a program upgrade module, which is connected to the main control module and is used to send firmware data to the main control module to update the program of the main control module.

7. A molded case circuit breaker according to claim 6, characterized in that, The program upgrade module includes a local offline upgrade interface or a remote online upgrade channel implemented by the remote communication control module. The local offline upgrade interface includes an ISP download socket and a signal current limiting resistor. The ISP download socket is connected to the ISP download pin of the main control module through the signal current limiting resistor, and is used for an external downloader to write firmware to the main control module. The remote online upgrade channel is configured such that the main control module receives firmware data packets through the remote communication control module, caches them in internal memory or external storage chip, erases the original program and writes new firmware after verification.

8. A molded case circuit breaker according to claim 7, characterized in that, The ISP download pin of the main control module includes a program data pin and a download clock pin; the local offline upgrade interface also includes a reset pin, which is configured to be pulled low when the downloader is connected to trigger the main control module to enter the built-in ISP burning startup mode.

9. A molded case circuit breaker according to claim 7, characterized in that, In the remote online upgrade channel, the main control module is configured to perform CRC verification after receiving a complete firmware data packet. After the verification is successful, it switches to the firmware update partition, writes the cached new firmware to the main program Flash area, and automatically restarts to run the new version control program after the writing is completed.

Images