Single-phase electrical fire protection current limiting protector
By using intelligent algorithms and high-end semiconductor technology in electrical fire-proof current-limiting protectors, short-circuit circuits are predicted and quickly cut off, which solves the problem that traditional equipment cannot effectively suppress short-circuit electric sparks, and achieves a smaller size and faster response current-limiting protection effect.
Patent Information
- Application Number
- CN202421156226.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-25
- Publication Date
- 2025-04-04
- Estimated Expiration
- 2034-05-25
AI Technical Summary
Traditional circuit breakers and current limiting protectors cannot effectively suppress instantaneous electric sparks when short-circuited, and are large in size and have a long reaction time, so they cannot cut off the circuit in time, resulting in difficult to prevent the hazards of electrical fires.
Adopting advanced detection technology and high-end semiconductor technology, the short circuit occurs in advance through intelligent algorithms and quickly cut off the circuit, a single-phase electrical fire-restricted current protector is designed, mainly composed of MOS circuit module, AC-DC conversion circuit module, voltage stabilization circuit module, current acquisition circuit module, voltage acquisition circuit module, control module and warning module.
It realizes the rapid driving of the current limit protector operation on the us-level time scale, shortens the short-circuit operation time, effectively suppresses the generation of instantaneous electric sparks, improves the safety and reliability of electrical fire detection, and reduces the volume of the current limit protector.
Smart Images
Figure CN222721120U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of electrical fire-proof current-limiting protectors, and in particular to a single-phase electrical fire-proof current-limiting protector, which is mainly used for protecting against electrical fires caused by instantaneous electric sparks. Background Art
[0002] With the rapid development of science and technology, high-power equipment such as new energy charging piles are increasing, power consumption is increasing, and electrical fires are becoming more frequent, causing huge losses to people and property. Short circuit is one of the main factors for electrical fires. When a short circuit occurs, the short circuit fault point has very large energy at the moment of short circuit, which can instantly generate a high temperature. The contact material also melts due to the high temperature, and the sparks generated instantly can easily ignite the surrounding combustibles.
[0003] Traditional circuit breakers can cut off the circuit after a short circuit occurs to avoid the harm of a continuous short circuit. Due to the way the excitation coil is tripped, the short circuit action time is usually tens of milliseconds. In other words, traditional circuit breakers need to drive the excitation coil to trip at a larger short circuit current, and cannot effectively suppress the spark during a short circuit. Traditional current limiting protectors are large in size and have a long reaction time. They cannot effectively cut off the circuit in time to prevent disasters. Summary of the invention
[0004] The purpose of the utility model is to provide a current limiting protector that can be driven to act quickly when an instantaneous electric spark occurs, and the short-circuit action time is realized in the microsecond level. The structure of the current limiter is improved to realize a current limiting protector with a smaller volume, making electrical fire detection safer and more reliable.
[0005] The fireproof current limiting protector of the utility model adopts advanced detection technology and high-end semiconductor technology. Through intelligent algorithms, it can predict the occurrence of short circuits in advance and quickly cut off the circuit, which can quickly suppress the generation of sparks. In order to achieve the above-mentioned purpose, the utility model provides a single-phase electrical fire-proof current-limiting protector, which is mainly composed of a MOS circuit module, an AC-DC conversion circuit module, a voltage stabilizing circuit module, a current acquisition circuit module, a voltage acquisition circuit module, a control module, and an alarm module; it is characterized in that after the 230V AC mains is connected to the AC-DC conversion circuit module, a DC power is obtained, and the DC power is divided into two paths; one path passes through the voltage stabilizing circuit module to obtain a stable voltage of 3.3V, and then the stable voltage is input to the control circuit module; the other path provides an isolated power supply to the MOS drive circuit through an isolated DC isolation power supply; the power supply voltage is measured by resistor voltage division, and the voltage obtained by voltage division is collected by an AD module inside the control module; the signal output by the current transformer is sampled by the current sampling circuit module and the voltage sampling circuit module, and then input into the AD module inside the control module for collection and calculation; the current transformer is arranged on the neutral line of the AC mains to collect the current signal; the control module includes a microprocessor.
[0006] Preferably, the microprocessor is a microprocessor with a Cortex M4 core with a main frequency of up to 200M.
[0007] Preferably, an optical coupling isolation is used to drive the MOS driving circuit to work, and a protection circuit is added to the MOS driving circuit.
[0008] Preferably, a state detection circuit is also included, which detects the switch state of the MOS tube and whether a fault occurs through an isolation optical coupler.
[0009] Preferably, the warning module includes a liquid crystal display, a button, an LED indicator light and a buzzer; the liquid crystal display is used to display voltage, current and power.
[0010] Preferably, the sampling rate of the current acquisition circuit is 200 kHz, and the sampling time is 5 us.
[0011] Preferably, a fixed time moving window is used to record the most recent 10 current sampling points in real time.
[0012] Based on the protection method of the single-phase electrical fire-proof current-limiting protector, step 1, building a sampling and detection circuit of the current-limiting protector;
[0013] Step 2, initializing the circuit parameters of the current limiting protector and setting the sampling frequency of the sampling circuit;
[0014] Step 3, collecting the current signal of the circuit through a circuit transformer, processing the current signal through the current collection circuit module and the voltage collection circuit module, and then inputting the current signal into the control module for processing and calculation;
[0015] Step 4, determine whether the current sampled data has a mutation. If there is no mutation, execute step 3; if there is a mutation, execute step 5;
[0016] Step 5, eliminating electromagnetic interference through a digital filtering processing circuit; calculating whether the changes of the 10 current sampling points meet the instantaneous rise value during a short circuit through a control module, and judging whether the rise value exceeds a threshold; if it exceeds, judging it as a short circuit, and executing step 6; if it does not exceed, returning to executing step 3;
[0017] Step 6, execute the current limiting protection action, and sound an alarm through the warning circuit module, and generate an audible and visual alarm. Preferably, in order to avoid serious heating of the MOS due to overload, the protector detects the current size in real time. If there is a current overload, the protector will disconnect the power supply circuit within a set time, sound an audible and visual alarm, and report to the management platform.
[0018] Preferably, in order to avoid serious heating of MOS due to overload, the protector detects the current size in real time. If there is a current overload, the protector will disconnect the power supply circuit within a set time, sound and light alarm, and report to the management platform.
[0019] Compared with the prior art, the beneficial effects of the present invention are: based on the overall design considerations, the overall size is reduced. 1. The relatively advanced mutual inductor technology is adopted, and the short-circuit current can be detected with a smaller volume, which has the characteristics of high saturation, low delay, and low distortion, so that the short-circuit fault can be accurately and quickly identified in the subsequent data processing and algorithm. 2. The new MOS tube is adopted, which can be quickly shut down to achieve uS-level cut-off of the fault circuit.
[0020] The fire-proof current-limiting protector obtains the current waveform signal through the current transformer. In order to quickly predict the short-circuit fault, the current sampling rate is 200kHZ, and the current data of one point is collected in 5uS. The fixed time moving window is used to record the 10 most recent current sampling points in real time. In terms of algorithm, first determine whether the current sampling point has a mutation. If there is a mutation, further eliminate electromagnetic interference through digital filtering, wherein the digital filtering includes 10-point moving average filtering, fluctuation filtering, etc. By detecting and calculating whether the changes of the 10 current sampling points meet the instantaneous rise during the short circuit and exceed the limit, it is judged as a short circuit, an audible and visual alarm is generated, and it is reported to the management platform. In addition, in order to avoid serious heating of MOS due to overload, the protector detects the current size in real time. If there is a current overload, the protector will disconnect the power supply circuit within the set time, and an audible and visual alarm will be issued, and it will be reported to the management platform to avoid heating of MOS and accelerate insulation aging due to overload heating of the line.
[0021] Based on the protection method of the single-phase electrical fire-proof current-limiting protector, step 1, building a sampling and detection circuit of the current-limiting protector;
[0022] Step 2, initializing the circuit parameters of the current limiting protector and setting the sampling frequency of the sampling circuit;
[0023] Step 3, collecting the current signal of the circuit through a circuit transformer, processing the current signal through the current collection circuit module and the voltage collection circuit module, and then inputting the current signal into the control module for processing and calculation;
[0024] Step 4, determine whether the current sampled data has a mutation. If there is no mutation, execute step 3; if there is a mutation, execute step 5;
[0025] Step 5, eliminating electromagnetic interference through a digital filtering processing circuit; calculating whether the changes of the 10 current sampling points meet the instantaneous rise value during a short circuit through a control module, and judging whether the rise value exceeds a threshold; if it exceeds, judging it as a short circuit, and executing step 6; if it does not exceed, returning to executing step 3;
[0026] Step 6, execute the current limiting protection action, and sound an alarm through the warning circuit module to generate an audible and visual alarm. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 This is the structural flow chart of a single-phase electrical fire-proof current-limiting protector.
[0028] Figure 2 It is a method flow chart of single-phase electrical fire protection current limiting protector DETAILED DESCRIPTION
[0029] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.
[0030] refer to Figure 1 A single-phase electrical fire-proof current-limiting protector is mainly composed of a MOS circuit module, an AC-DC conversion circuit module, a voltage stabilizing circuit module, a current acquisition circuit module, a voltage acquisition circuit module, a control module, and a warning module; it is characterized in that a 230V AC mains power supply is connected to the AC-DC conversion circuit module to obtain a DC power supply, and the DC power supply is divided into two paths; one path passes through the voltage stabilizing circuit module to obtain a stable voltage of 3.3V, and then the stable voltage is input to the control circuit module; the other path provides an isolated power supply to the MOS drive circuit through an isolated DC isolation power supply; the power supply voltage is measured by a resistor divider, and the voltage obtained by the voltage division is collected by an AD module inside the control module; the signal converted by the AC-DC module is input into the isolated DC-DC circuit module; the output signal of the isolated DC-DC circuit module is input into the MOS drive circuit module; the MOS drive circuit module drives the MOS circuit to work; the control module can also detect the working state of the MOS; it can detect whether the MOS tube is damaged or not. The signal output by the current transformer is sampled by the current sampling circuit module and the voltage sampling circuit module and then input into the AD module inside the control module for collection and calculation; the current transformer is set on the neutral line of the AC mains to collect the current signal; the control module includes a microprocessor. It also includes a liquid crystal display module, buttons, LED indicators, and a buzzer; the liquid crystal display module, buttons, LED indicators, and buzzers are all connected to the control module; the liquid crystal display screen is used to display real-time data such as voltage, current, power, and status, as well as parameter viewing and setting, and the device can be set through buttons. At the same time, the current status can be intuitively displayed through the LED.
[0031] The current signal sensed by the current transformer is collected and preprocessed by the current sampling circuit; at the same time, the voltage sampling circuit collects the power supply voltage signal; the output signals of the current sampling circuit module and the voltage sampling circuit module are transmitted to the control module;
[0032] In addition, in order to detect large currents at the moment of short circuit, the main device uses a microprocessor HC32F460KCTA with a Cortex M4 core with a main frequency of up to 200M. The AD sampling frequency is designed to be 200KHz, which meets the microsecond-level sampling rate at the moment of short circuit and the related algorithm calculation time.
[0033] Since the controlled circuit is a strong current, an optocoupler isolation driver is used, and a protection circuit is added to the MOS.
[0034] The fire-proof current-limiting protector obtains the current waveform signal through the current transformer. In order to quickly predict the short-circuit fault, the current sampling rate is 200kHZ, and the current data of one point is collected in 5uS. The fixed time moving window is used to record the 10 most recent current sampling points in real time. In terms of algorithm, first determine whether the current sampling point has a mutation. If there is a mutation, further eliminate electromagnetic interference through digital filtering, wherein the digital filtering includes 10-point moving average filtering, fluctuation filtering, etc. By detecting and calculating whether the changes of the 10 current sampling points meet the instantaneous rise during the short circuit and exceed the limit, it is judged as a short circuit, an audible and visual alarm is generated, and it is reported to the management platform. In addition, in order to avoid serious heating of MOS due to overload, the protector detects the current size in real time. If there is a current overload, the protector will disconnect the power supply circuit within the set time, and an audible and visual alarm will be issued, and it will be reported to the management platform to avoid heating of MOS and accelerate insulation aging due to overload heating of the line.
[0035] Based on the protection method of the single-phase electrical fire-proof current-limiting protector, step 1, building a sampling and detection circuit of the current-limiting protector;
[0036] Step 2, initializing the circuit parameters of the current limiting protector and setting the sampling frequency of the sampling circuit;
[0037] Step 3, collecting the current signal of the circuit through a circuit transformer, processing the current signal through the current collection circuit module and the voltage collection circuit module, and then inputting the current signal into the control module for processing and calculation;
[0038] Step 4, determine whether the current sampled data has a mutation. If there is no mutation, execute step 3; if there is a mutation, execute step 5;
[0039] Step 5, eliminating electromagnetic interference through a digital filtering processing circuit; calculating whether the changes of the 10 current sampling points meet the instantaneous rise value during a short circuit through a control module, and judging whether the rise value exceeds a threshold; if it exceeds, judging it as a short circuit, and executing step 6; if it does not exceed, returning to executing step 3;
[0040] Step 6, execute the current limiting protection action, and sound an alarm through the warning circuit module to generate an audible and visual alarm. Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not within the scope of protection of the claims of the present invention. Any technician familiar with the technical field within the technical scope disclosed by the present invention, according to the technical solution and the inventive concept of the present invention, shall be covered within the scope of protection of the present invention.
Claims
1. A single-phase electrical fire-proof current-limiting protector, mainly composed of a MOS circuit module, an AC-DC conversion circuit module, a voltage stabilizing circuit module, a current acquisition circuit module, a voltage acquisition circuit module, a control module, and a warning module; characterized in that: After 230V AC mains is connected to the AC-DC conversion circuit module, DC power is obtained, and the DC power is divided into two paths; one path passes through the voltage stabilizing circuit module to obtain a stable voltage of 3.3V, and then the stable voltage is input to the control circuit module; the other path provides an isolated power supply to the MOS drive circuit through an isolated DC isolation power supply; the power supply voltage is measured by resistor voltage division, and the voltage obtained by voltage division is collected by an AD module inside the control module; the signal output by the current transformer is sampled by the current sampling circuit module and the voltage sampling circuit module, and then input into the AD module inside the control module for collection and calculation; the current transformer is set on the neutral line of the AC mains to collect the current signal; the control module includes a microprocessor.
2. A single-phase electrical fire-proof current-limiting protector according to claim 1, characterized in that: The microprocessor is a Cortex M4 core microprocessor with a main frequency of up to 200M.
3. A single-phase electrical fire-proof current-limiting protector according to claim 1, characterized in that: The MOS driving circuit is driven by optical coupling isolation, and a protection circuit is added to the MOS driving circuit.
4. A single-phase electrical fire-proof current-limiting protector according to claim 3, characterized in that: It also includes a state detection circuit, which detects the switch state of the MOS tube and whether a fault occurs through an isolation optical coupler.
5. A single-phase electrical fire-proof current-limiting protector according to claim 1, characterized in that: The warning module includes a liquid crystal display, buttons, LED indicator lights and a buzzer; the liquid crystal display is used to display voltage, current and power.
6. A single-phase electrical fire-proof current-limiting protector according to claim 1, characterized in that: The sampling rate of the current acquisition circuit is 200kHZ and the sampling time is 5us.
7. A single-phase electrical fire-proof current-limiting protector according to claim 1, characterized in that: A fixed time moving window is used to record the most recent 10 current sampling points in real time.