Arc fault generating device and control method
By using voltage and current sensors to determine the electrode contact state and combining it with PID closed-loop control, the problem of the difficulty in quickly determining the arcing time in arc fault generating devices is solved, and efficient simulation and detection of arc fault protection devices are realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- MINJIANG UNIVERSITY
- Filing Date
- 2022-11-29
- Publication Date
- 2026-06-09
Smart Images
Figure CN115840099B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for generating an arc fault, and more particularly to a device and control method capable of optimizing the control logic for generating an arc. Background Technology
[0002] In building construction, arc faults are a type of fault characterized by high danger, strong concealment, and great uncertainty. If not eliminated in time, they can cause electrical fires, threatening production and daily life, especially in high-rise buildings where such fires can result in severe economic losses. Installing appropriate protective products is a common method to prevent such electrical fires. Arc fault protection products mainly include arc fault detectors and arc fault circuit breakers, with arc fault detection being a key technology in both. Therefore, arc fault tests are conducted during both the product development and factory inspection stages. National standards GB 14287.4 "Electrical Fire Monitoring Systems Part 4: Arc Fault Detectors" and GB / T 31143 "Arc Fault Protection - General Requirements for Protective Electrical Appliances (AFDD)" clearly stipulate these tests, including methods for simulating arc faults and requirements for the maximum arcing time under different test currents. Arc fault generating devices are one type of equipment required for simulating arc faults. The arc fault generating device consists of carbon and copper electrodes, one of which is stationary and the other is movable. When the two electrodes come into contact and current flows through them, the movable electrode is laterally adjusted to separate it from the stationary electrode until an arc is generated. The separation distance between the two electrodes and the arcing speed directly affect the arc fault simulation effect. This invention aims to study an arc fault generator for detecting arc faults in protective electrical appliances, improve the structure and control method of the arc fault generating device, and thus increase the success rate of arc fault simulation. Summary of the Invention
[0003] Therefore, a new arc fault generating device and control method are needed to achieve the technical effect of quickly determining the arcing time.
[0004] To achieve the above objectives, the inventors provide an arc fault generating device, comprising:
[0005] An arc generator includes a first electrode, a second electrode, a voltage sensor for detecting the voltage between the first and second electrodes, a current sensor for detecting the current in either the first or second electrode, and a control unit for receiving signals from the voltage and current sensors. The control unit is also used to determine the contact state between the first and second electrodes based on the signal from the voltage sensor. When the first and second electrodes are determined to be in stable contact, an arc generation simulation is performed. The control unit also determines the arcing time based on the detection signals from the voltage and current sensors and adjusts the allowable inter-electrode voltage value of the arc generator based on the arcing time.
[0006] In some embodiments of this application, the control unit is used to calculate: the effective value U of the periodic voltage based on the voltage u detected by the voltage sensor, satisfying 80%U s >U>20V, and the ratio between the contact voltage and the line current is greater than the contact resistance R. jc The duration of the finite state, as the arcing time, U s This is the power supply voltage.
[0007] In some embodiments of this application, an arc fault protector test circuit is also included. The arc fault protector test circuit is used to connect to the arc generator when the contact state of the first electrode and the second electrode is contact. The control unit is also used to enter the arc generation simulation stage when the contact state of the first electrode and the second electrode is stable contact, and execute a PID closed-loop control mode, including a voltage regulation loop, a displacement loop, and a speed loop. The voltage regulation loop is the outer loop, which takes the continuous arc burning time deviation as input and outputs a given voltage value. The middle loop is the displacement loop, which takes the voltage deviation as input and outputs the displacement change. The inner loop is the speed loop, which takes the displacement deviation as input and is used to adjust the stepper motor's operating speed.
[0008] In some embodiments of this application, the arc fault protector test circuit is also connected to a test circuit status detection module and a test circuit control module.
[0009] In some embodiments of this application, a contact state detection circuit is further included, comprising a current-limiting resistor R, a DC power supply module, and a contactor KM1. The contact state detection circuit is used to disengage from the arc generator when the first electrode and the second electrode are determined to be in a stable contact state. The control unit is also used to execute a detection closed-loop control mode when the contact state detection circuit is in contact with the arc generator. The detection closed-loop control mode calculates the voltage change as a feedback quantity and adjusts the relative movement speed of the two electrodes until the voltage between the two electrodes remains constant.
[0010] An arc fault occurrence control method, applicable to the arc fault generating device as described above, includes the following steps: a voltage sensor and a current sensor respectively detect the voltage and current between a first electrode and a second electrode; a control unit receives signals from the voltage sensor and the current sensor; determines the contact state between the first electrode and the second electrode based on the detected voltage sensor signal; when it is determined that the first electrode and the second electrode are in stable contact, performs arc generation simulation; further determines the arcing time based on the detection signals from the voltage sensor and the current sensor; and adjusts the allowable value of the inter-electrode voltage of the arc generator based on the arcing time.
[0011] In some embodiments of this application, the step of the control unit calculating the effective value U of the periodic voltage based on the voltage u detected by the voltage sensor, and calculating 80%U s >U>20V, and the ratio between the contact voltage and the line current is greater than the contact resistance R. jc The duration of the finite state, as the arcing time, U s This is the power supply voltage.
[0012] In some embodiments of this application, when the contact state between the first electrode and the second electrode is stable, the arc generation simulation stage is entered, and a PID closed-loop control step is also included, including a voltage regulation loop, a displacement loop, and a speed loop. The voltage regulation loop is the outer loop, which takes the continuous arcing time deviation as input and outputs a given voltage value. The middle loop is the displacement loop, which takes the voltage deviation as input and outputs the displacement change. The inner loop is the speed loop, which takes the displacement deviation as input and is used to adjust the stepper motor's operating speed.
[0013] In some embodiments of this application, the device further includes: an arc fault protector test circuit, which is connected to a test circuit status detection module and a test circuit control module; a contact status detection circuit, which includes a current-limiting resistor R, a DC power supply module, and a contactor KM1, wherein the contact status circuit control and monitoring module is used to control and detect the operating status of KM1; the control method further includes the step of executing a detection closed-loop control mode when the contact status detection circuit is in contact with the arc generator, wherein the detection closed-loop control mode calculates the voltage change as a feedback quantity and adjusts the relative movement speed of the two electrodes until the voltage between the two electrodes remains constant.
[0014] In some embodiments of this application, when it is determined that the first electrode and the second electrode are in stable contact, the control unit controls the contact state detection circuit to disengage from the contact state with the arc generator.
[0015] Unlike existing technologies, the above technical solution determines the arcing time by designing a voltage threshold detection method, and uses the arcing time to feed back the voltage of the control electrode, thereby achieving a better technical effect in simulating fault arcs. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the arc generator according to a specific embodiment of the present invention;
[0017] Figure 2 This is a diagram of an arc fault generating device according to another embodiment of the present invention;
[0018] Figure 3 The schematic diagram of the PID closed-loop control principle described in a specific embodiment of the present invention is shown below.
[0019] Figure 4 This is a diagram of the arc fault occurrence control method according to a specific embodiment of the present invention;
[0020] Figure 5 This is a flowchart illustrating the operation of the arc fault generating device according to a specific embodiment of the present invention. Attached Figure Description
[0022] 1. First electrode; 2. Second electrode; 3. Stepper motor; 4. Fixed bracket; 5. Sliding module; 6. Electrode mounting platform; 7. Fastening screw; 8. Lead screw; 91. Photoelectric switch sensor; 92. Photoelectric switch sensor; 93. Light shield. Detailed Implementation
[0023] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.
[0024] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.
[0025] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.
[0026] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order relationship between these entities or operations.
[0027] Unless otherwise specified, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.
[0028] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.
[0029] In the description of the embodiments of this application, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or drawings. They are only for the purpose of describing the specific embodiments of this application or for the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.
[0030] Unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," and "setting," as used in the description of the embodiments of this application, should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction between two components. For those skilled in the art to which this application pertains, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.
[0031] Please see Figure 1 The illustrated embodiment is an arc fault generating device, comprising: an arc generator, the arc generator including a first electrode 1, a second electrode 2, a voltage sensor for detecting the voltage between the first and second electrodes, a current sensor for detecting the current of either the first or second electrode, and a control unit for receiving signals from the voltage sensor and the current sensor. The control unit is also used to determine the contact state between the first and second electrodes based on the signal from the voltage sensor. When the first and second electrodes are determined to be in stable contact, an arc generation simulation is performed. Furthermore, the arcing time is determined based on the detection signals from the voltage and current sensors, and the allowable inter-electrode voltage value of the arc generator is adjusted according to the arcing time. Figure 1 In the illustrated embodiment, the data acquisition unit may include one voltage sensor and one current sensor. The voltage sensor is used to detect the voltage across the electrodes during contact, and in the arc fault experiment, it is used to detect the voltage u between the two electrodes before and after the occurrence of the fault arc. The current sensor is used to detect the current i passing through the electrodes before and after the occurrence of the fault arc. During the contact process when the movable electrode moves laterally towards the fixed electrode, the voltage sensor detects the voltage across the electrodes in real time. When the voltage sensor reading is stable, it can be determined that the first and second electrodes are in stable contact. At this time, the arcing time is determined based on the voltage and current, and the voltage is modulated in a closed loop according to the arcing time, so that the generated arc meets the requirements and is better used for simulating fault arcs. Compared with the traditional solution of designing a pressure sensor to detect the pressure between the first and second electrodes, this solution eliminates the need to determine the initial and final states of electrode contact, and avoids the possibility that the copper electrode may penetrate the surface of the carbon electrode after repeated use, and the pressure sensor sensing element will be pressed more tightly, which may damage it when its range is exceeded. The advantage of using a voltage sensor for judgment is that even if the previous operation did not fully reset and the two electrodes are in an unstable state of initial contact, this method can be directly applied for judgment. Subsequently, the arcing time is used to determine the allowable value of the inter-electrode voltage. This allowable value is a range, influenced by the electrode spacing under stable input power conditions. Limiting this range helps the system stably generate an arc during the arcing stage, preventing arc shortening due to device feedback adjustment failure, and effectively improving the practicality of the arc fault generation device.
[0032] In some embodiments of this application, the control unit is used to calculate: the effective value U of the periodic voltage based on the voltage u detected by the voltage sensor, satisfying 80%U s >U>20V, and the ratio between the contact voltage and the line current is greater than the contact resistance R.jc The duration of the finite state, as the arcing time, U s The power supply voltage is used. Determining the arcing time can quickly identify whether a valid arc exists between the two electrodes. In a specific embodiment, the arcing time can be determined by the control unit running an arcing time calculation program, thereby identifying faulty arcs. Combining the electrical characteristics of the faulty arc, the effective value of the periodic voltage U and the resistance R between the two electrodes are calculated by processing the voltage between the two electrodes and the current flowing through them. h This serves as the basis for determining the arc initiation time and the duration of arc burning. Before arcing, the two electrodes are in contact, and the effective value of the periodic voltage U at this time is also detected and recorded as the contact voltage U between the two electrodes. jc The line current is the test current. At this point, there is no arc resistance between the electrodes, only contact resistance. The average contact resistance R is calculated using the ratio of the contact voltage to the test current. jc When an electric arc is generated, there is an arc voltage and an arc resistance between the two electrodes. Technicians, through numerous experiments, have concluded that the voltage between the two electrodes during the arc-drawing process is typically greater than 20V and lower than the power supply voltage. When the two electrodes are completely separated, or when the arc intermittently extinguishes during separation and cannot reignite, the effective value of the periodic voltage is equal to the power supply voltage U. s At this point, the current flowing through the electrodes is 0, and the resistance between the two electrodes is an infinite value. The criterion for determining the presence of an electric arc can be set as: 80% U s >U>20V and R h It is greater than the contact resistance R jc When the value is finite, an electric arc is considered to exist between the two electrodes. 80%U s The threshold can be adjusted to 70%-90% as needed. Under the condition that the condition is met, the start and end times of arcing are recorded, and the duration of arcing t is also recorded. arc This method is computationally simple, involves no complex calculations, ensures real-time device control, and improves experimental efficiency.
[0033] In some further embodiments of this application, an arc fault protector test circuit is also included. This arc fault protector test circuit is used to connect to the arc generator when the first electrode and the second electrode are in contact. The control unit is further used to enter the arc generation simulation stage when the first electrode and the second electrode are in stable contact, and to execute a PID closed-loop control mode. Figure 2In some of the embodiments shown, PID control logic applicable to this device is illustrated. Specifically, the control unit is also used to execute a closed-loop control mode of the PID, including a voltage regulation loop, a displacement loop, and a speed loop. The voltage regulation loop is the outer loop, which takes the continuous arcing time deviation as input and outputs a given voltage value. The middle loop is the displacement loop, which takes the voltage deviation as input and outputs the displacement change. The inner loop is the speed loop, which takes the displacement deviation as input and is used to adjust the stepper motor's operating speed. The device includes a voltage regulator, a displacement regulator, and a speed regulator. These three regulators can be virtual program modules in the control unit or physical devices. Taking the voltage regulator, displacement regulator, and speed regulator as virtual program modules as an example, the voltage regulator can adjust the contact of the electrodes with the arc generator. The control unit is also used to execute a detection closed-loop control mode when the contact state detection circuit contacts the arc generator. The detection closed-loop control mode calculates the voltage change as feedback and adjusts the relative movement speed of the two electrodes until the voltage between the two electrodes remains constant. The principle of the closed-loop control mode for detection here is as follows: During the lateral movement of the movable electrode towards the fixed electrode, the voltage sensor detects the voltage across the electrodes in real time and uses this as feedback to modulate the motor rotation speed in a closed loop during the contact process. This ensures stable electrical contact between the two electrodes and avoids impact on the fixed support caused by the impact force at the moment of contact. This differs from the traditional pressure sensor control scheme in that the current method of judging electrode contact through pressure sensors often considers the change in contact force at the moment of contact. If the electrode approaches too quickly, the initial state of the pressure sensor will change continuously at the moment of impact until it reaches the limit value. If it is not manually reset after a period of use, the actual pressure value cannot be accurately measured. Meanwhile, the initial pressure value of the pressure sensor is not completely consistent in the initial state of each experiment, making it difficult to guarantee the contact pressure criterion. Furthermore, if an anomaly occurs in the previous experiment causing the movable electrode to fail to detach from the fixed electrode, the initial pressure detected by the pressure sensor is actually the pressure at electrode contact. Subsequent attempts to use the difference between the initial and real-time pressures as the criterion for electrode contact will result in misjudgments. Additionally, copper electrodes may penetrate the surface of carbon electrodes, and the pressure sensor's sensing element will be compressed more tightly, potentially causing damage if its range is exceeded. The inventors of this application have identified these problems and designed a voltage signal value to determine the state of the electrodes: no contact, initial contact, and stable contact. In the no-contact state, the voltage between the electrodes is 0. In the initial contact state, the voltage between the electrodes is very small, but the voltage fluctuation is large. In the stable contact state, the voltage between the electrodes is at a stable value.During the test experiment of arc fault protection electrical appliances, the voltage detected by the voltage sensor and the current detected by the current sensor are also transmitted to the computer through the analog input channel of the multi-functional high-speed acquisition card. The data acquisition and control program reads the data and converts it in the monitoring and controller to restore the voltage and current values in the actual circuit. These two waveform data will be used as the input of the arithmetic unit, which is the premise for realizing the rated calculation of arcing time and the implementation of closed-loop control algorithm.
[0034] The arithmetic unit, part of the monitoring and controller, is programmed using LabVIEW software and mainly includes closed-loop modulation of the contact process, arc time calculation program, and closed-loop control algorithm program. The closed-loop modulation of the contact process uses the voltage between the two electrodes as feedback. When the movable electrode moves towards the fixed electrode, the monitoring and controller calculates the average voltage value for every 10 sampling points and records it as the current voltage value. This value is then compared with the operating voltage U of the DC voltage source. d The difference between the two is used as a criterion for adjusting the motor speed, updating the frequency of the stepper motor control pulse PWM, thereby modulating the speed until the voltage between the two electrodes is lower than U. d And it has remained basically stable.
[0035] Others such as Figure 3 In the specific embodiment shown, the arc fault generating device also includes a monitoring and controller comprised of a computer, a multi-functional high-speed data acquisition card, a data acquisition and processing unit, and a device control program executed by the processing unit. The multi-functional high-speed data acquisition card is installed on the computer's PCIE interface as an input / output module, capable of outputting control commands and acquiring real-time device operating information. The model is PCIE1816H, which has analog signal input / output channels, digital signal input / output channels, and a PWM pulse output channel. The monitoring and controller transmits speed control commands to the power system through the PWM pulse output channel of the multi-functional high-speed data acquisition card, transmits direction control commands to the power system through the digital signal output channel (DO), and receives actuator operating status information from the data acquisition module through the analog signal input channel (AI). This operating status information includes voltage waveform data between the two electrodes and current waveform data flowing through the electrodes. Simultaneously, it controls the arc fault protection electrical test circuit and contact state detection circuit through the test circuit control module and the contact state circuit control module via the digital signal output channel (DO); and detects the operation of the test circuit and detection circuit through the digital signal input channel (DI). The data acquisition and control program is used to acquire and process the operating status of the actuator and generate the direction signal and PWM pulse signal required for the stepper motor to operate. Based on the displacement and velocity changes output by the closed-loop control algorithm program, the frequency and number of pulses of the direction signal and PWM pulse signal are updated in real time.
[0036] Figure 3 The diagram also shows that the arc fault protection electrical device test circuit is designed using contactors, including contactor KM2, based on the test standards for arc fault protection electrical devices. The control process of all switches is automatically completed by the monitoring and controller following a predetermined experimental procedure. The test circuit control module uses a serial-to-parallel conversion register to expand the DO channels of the data acquisition card and controls the contactors via an optocoupler-isolated amplification drive circuit. Control of the operation of all switches in the test circuit can be completed through only three DO channels of the data acquisition card. The test circuit status monitoring module is designed using a parallel-to-serial conversion register, using the open / closed state of the contactor auxiliary contacts as feedback for the on / off state of the contactor main contacts. This feedback is connected to the parallel-to-serial conversion circuit, encapsulating the operating status of all switches into serial data. This data is received by the monitoring and controller through the three DI channels of the data acquisition card. The monitoring and controller processes the received serial data to ultimately identify the operating information of all switches.
[0037] exist Figure 3 Some of the embodiments shown include an actuator; please refer to the specific structure of the actuator in conjunction with... Figure 1The components include an arc generator and its first electrode 1, second electrode 2, stepper motor 3, mounting bracket 4, sliding module 5, electrode mounting platform 6, fastening screw 7, lead screw 8, photoelectric switch sensor 91 and photoelectric switch sensor 92, and light shield 93. The first electrode 1 can be a stationary electrode made of carbon with a flat contact surface; the second electrode 2 can be a movable electrode made of copper with a pointed contact surface. The stationary electrode is fixedly mounted on the electrode mounting platform 6. Both the movable and stationary electrodes are replaceable components and can be fixed and removed using the fastening screw 7. The electrode surface shape and electrode material can be changed according to experimental needs. The movable electrode is mounted on the sliding module 81 via the mounting bracket 4. The sliding module 81 is connected to the motor lead screw 8 and moves laterally under the drive of the stepper motor. Initially, the two electrodes are completely separated. When the motor 3 rotates, it moves the sliding module 81, which in turn moves the movable electrode laterally, causing it to contact or separate from the stationary electrode. The limit function module consists of photoelectric switch sensor 91 and photoelectric switch sensor 92, and light shield 93. Photoelectric switch sensors 91 and 92 are U-shaped photoelectric switch sensors, and light shield 93 is made of hard stainless steel sheet. When the movable electrode moves laterally, if it exceeds the preset stroke, the light shield 93 will insert into the groove of the U-shaped photoelectric switch sensor, causing the level signal output by the photoelectric switch sensor to change. This signal is input into the monitoring and controller via the DI channel of the high-speed data acquisition card to limit the movement of the electrode, forcibly stop the PWM pulse, and stop the motor from running. The motor can only be driven to run in reverse if the direction of the electrode movement is changed, so as to protect the movable electrode from moving beyond the maximum allowable stroke of the device and causing damage to the mechanical parts.
[0038] In order to control the above scheme, in such cases... Figure 4 In the described embodiment, an arc fault occurrence control method is also introduced, applicable to the arc fault generating device as described above. The method further includes the following steps: S40, a voltage sensor and a current sensor respectively detect the voltage and current between the first electrode and the second electrode; S41, the control unit determines the contact state between the first electrode and the second electrode based on the detected signal from the voltage sensor; S42, when it is determined that the first electrode and the second electrode are in stable contact, an arc generation simulation is performed, and the arcing time is determined based on the detection signals from the voltage sensor and the current sensor. The allowable value of the inter-electrode voltage of the arc generator is adjusted according to the arcing time. This scheme can detect the voltage across the electrodes in real time using a voltage sensor and use this as feedback to determine whether a stable contact state is achieved. Compared to the traditional scheme of designing a pressure sensor to detect the pressure between the first electrode and the second electrode, this eliminates the need to determine the initial and final states of electrode contact, then determine the arcing time, and perform closed-loop modulation of the voltage based on the arcing time, thereby ensuring that the generated arc meets the requirements and is better suited for simulating fault arcs.
[0039] In some embodiments of this application, the method further includes the step of the control unit calculating the effective value U of the periodic voltage based on the voltage u detected by the voltage sensor, and calculating the value that satisfies 80% U. s >U>20V, and the ratio between the contact voltage and the line current is greater than the contact resistance R. jc The duration of the finite state, as the arcing time, U s The voltage is the power supply voltage. The above determination method is simple to calculate, does not involve complex operations, ensures the real-time control of the device, and improves the efficiency of the experiment.
[0040] In some embodiments of this application, when the contact state between the first electrode and the second electrode is stable, the arc generation simulation stage is entered. The system also includes a PID closed-loop control step, comprising a voltage regulation loop, a displacement loop, and a speed loop. The voltage regulation loop is the outer loop, using the continuous arcing time deviation as input, and the voltage regulator outputs a given voltage value. The middle loop is the displacement loop, using the voltage deviation as input, and the displacement regulator outputs the displacement change. The inner loop is the speed loop, using the displacement deviation as input to adjust the stepper motor's operating speed. By designing the above-mentioned PID closed-loop control, the voltage value can be adjusted by controlling the arcing time, the displacement can be controlled by the voltage deviation, and the motor speed can be adjusted by the displacement deviation, ultimately achieving dynamic control of arc generation.
[0041] In some embodiments of this application, the device further includes: an arc fault protector test circuit, which is connected to a test circuit status detection module and a test circuit control module; a contact status detection circuit, which includes a current-limiting resistor R, a DC power supply module, and a contactor KM1; the contact status circuit control and monitoring module is used to control and detect the operating status of KM1; the control method further includes the step of executing a detection closed-loop control mode when the contact status detection circuit contacts the arc generator, wherein the detection closed-loop control mode calculates the voltage change as a feedback quantity and adjusts the relative movement speed of the two electrodes until the voltage between the two electrodes remains constant. The above design ensures that KM1 can be put into normal operation, achieving the effect of contact status detection.
[0042] In some embodiments of this application, when the first electrode and the second electrode are determined to be in stable contact, the control unit controls the contact state detection circuit to disengage from the arc generator. This solution effectively achieves the function of disconnecting after reaching a stable contact state.
[0043] Next, please see... Figure 5 ,exist Figure 5In the embodiment shown, the method begins with step 1: KM1 is closed. When the arc generating device is powered on, contactor KM1 is closed first, KM2 remains open, and the contact state detection circuit is put into operation.
[0044] Step 2: The voltage sensor detects the voltage between the two electrodes to determine whether the electrodes are in contact. If they are in contact, the arc fault experiment will begin directly, and the process will proceed to step 5. If they are not in contact, the process will return to step 2.
[0045] Step 3: Control the stepper motor to rotate at a high speed at a given initial speed, thereby driving the movable electrode to move laterally towards the fixed electrode.
[0046] Step 3: During the movement of the movable electrode, the voltage between the two electrodes is detected in real time, and the stepper motor speed is adjusted according to the closed-loop modulation control mode of the contact process until the voltage between the two electrodes remains stable. When this is the case, the two electrodes are considered to have achieved complete electrical contact.
[0047] Step 4: Control KM1 to disconnect, and the contact status detection circuit will stop running.
[0048] Step 5: Control KM2 to close, and the arc fault protection electrical appliance test circuit will be put into operation. The arc fault protection electrical appliance test circuit will complete the switching of the corresponding switches according to the predetermined experimental procedure in the monitoring and controller.
[0049] Step 6: The data acquisition unit detects the current voltage of the two electrodes and the current passing through the electrodes in real time, determines whether current is passing through the two electrodes, and prepares for arcing.
[0050] Step 7: After current flows through the two electrodes, the movable electrode adjusts the arc gap and electrode movement speed according to the closed-loop control mode based on incremental PID to start arc pulling.
[0051] Step 8: After the arc termination condition is met, exit the closed-loop control mode and the movable electrode quickly returns to the initial position.
[0052] Step 9: Power off the device; the test is over.
[0053] In step 3, the closed-loop modulation mode of the contact process uses the voltage between the two electrodes as the feedback quantity. When the movable electrode moves towards the fixed electrode, the monitoring and controller calculates the average voltage value for every 10 sampling points of the acquired voltage signal and records it as the current voltage value. This value is then compared with the operating voltage U of the DC voltage source. dThe difference between the two is used as the input to adjust the speed regulator. The speed regulator uses incremental PID control. When the two electrodes first make contact, the current voltage deviates from the given voltage, and the frequency of the stepper motor control pulse PWM is updated, so that the stepper motor speed decreases and continues to move at a slow speed. When the average voltage measured twice remains unchanged, it is considered that the two electrodes have made contact.
[0054] Step 5 describes a closed-loop control mode based on incremental PID, which is built upon real-time data acquisition, arcing time calculation, and a closed-loop control algorithm. During the arcing process, the current effective voltage value U and arc resistance are calculated based on the real-time acquired voltage and current signals. The occurrence of an arc is determined by the voltage and arc resistance changes, and the duration of arcing t is calculated. arc Simultaneously, the current electrode spacing is calculated based on the number of output PWM pulses, and the real-time calculated parameters are used as feedback values for the incremental PID closed-loop control mode.
[0055] The mathematical model of the incremental PID algorithm is:
[0056] Δu(k)=u(k) -u(k - 1)
[0057] In the formula, u(k-1) and u(k) are the output values of the PID controller at time k, respectively. According to the PID control principle, the output of the PID controller is:
[0058]
[0059] therefore,
[0060] Δu(k)=(K p K i K d )e(k) - (K p Sell 2K d e(k - 1) out K d e(k - 2),
[0061] e(k), e(k-1), and e(k-2) are the PID controller input signal deviations at sampling times k, k-1, and k-2, respectively; K p K i K d These are the proportional coefficient, integral coefficient, and derivative coefficient of the PID controller, respectively.
[0062] When the movable electrode starts to arc, the maximum required sustained arc time is taken as the given arc time t. arc0Based on the arcing time deviation, the voltage regulator outputs a given voltage U0. The deviation between the given voltage value and the current effective voltage value U serves as the input to the displacement regulator, used to update the number of PWM pulse outputs and the motor rotation direction, controlling the number of rotations of the stepper motor and limiting the electrode spacing; the displacement regulator outputs the electrode spacing setpoint. The deviation between the electrode spacing setpoint output by the displacement regulator and the current electrode spacing serves as the input to the displacement regulator, used to update the frequency of the PWM pulses, thereby controlling the motor speed.
[0063] The conditions for ending the arc in step 6 include the arc duration meeting the set maximum arc duration limit and the maximum allowed time for the arc generating device test.
[0064] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Unless otherwise specified, an element defined by the phrase "comprising..." or "including..." does not exclude the presence of additional elements in the process, method, article, or terminal device that includes said element. Additionally, in this document, "greater than," "less than," "exceeding," etc., are understood to exclude the stated number; "above," "below," "within," etc., are understood to include the stated number.
[0065] Those skilled in the art will understand that the above embodiments can be provided as methods, apparatus, or computer program products. These embodiments may take the form of entirely hardware embodiments, entirely software embodiments, or embodiments combining software and hardware aspects. All or part of the steps in the methods involved in the above embodiments can be implemented by a program instructing related hardware, and the program can be stored in a computer-readable storage medium for executing all or part of the steps described in the methods of the above embodiments. The computer device includes, but is not limited to: personal computers, servers, general-purpose computers, special-purpose computers, network devices, embedded devices, programmable devices, smart mobile terminals, smart home devices, wearable smart devices, in-vehicle smart devices, etc.; the storage medium includes, but is not limited to: RAM, ROM, magnetic disks, magnetic tapes, optical disks, flash memory, USB flash drives, portable hard drives, memory cards, memory sticks, network server storage, network cloud storage, etc.
[0066] The above embodiments are described with reference to flowchart illustrations and / or block diagrams of the methods, apparatus (systems), and computer program products according to the embodiments. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a computer device to produce a machine, such that the instructions, which execute via the processor of the computer device, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.
[0067] These computer program instructions may also be stored in a computer device-readable storage medium that can direct a computer device to operate in a particular manner, such that the instructions stored in the computer device-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.
[0068] These computer program instructions can also be loaded onto a computer device, causing a series of operational steps to be performed on the computer device to produce a computer-implemented process, thereby providing instructions that execute on the computer device for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.
[0069] Although the above embodiments have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the above descriptions are merely embodiments of the present invention and do not limit the scope of patent protection of the present invention. Any equivalent structural or procedural transformations made using the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.
Claims
1. An arc fault generating device, characterized in that, include: An arc generator, comprising a first electrode and a second electrode, A voltage sensor is used to detect the voltage between the first electrode and the second electrode. A current sensor, used to detect the current in the first electrode or the second electrode. The control unit receives signals from a voltage sensor and a current sensor. It also determines the contact state between the first and second electrodes based on the voltage sensor signal. When a stable contact is detected, it simulates arc generation. Furthermore, it determines the arcing time based on the detection signals from the voltage and current sensors and adjusts the allowable inter-electrode voltage of the arc generator accordingly. The control unit calculates the effective value U of the periodic voltage based on the voltage u detected by the voltage sensor, ensuring it meets 80% accuracy. U s > U >20V, and the ratio between the contact voltage and the line current is greater than the contact resistance. R jc The duration of the finite state, as the arcing time, U s This is the power supply voltage. It also includes an arc fault protector test circuit, which is used to connect to the arc generator when the first electrode and the second electrode are in contact. The control unit is also used to enter the arc generation simulation stage when the first electrode and the second electrode are in stable contact, and execute the PID closed-loop control mode, including voltage regulation loop, displacement loop and speed loop. The voltage regulation loop is the outer loop, which takes the continuous arc burning time deviation as input and outputs a given voltage value. The middle loop is a displacement loop, with voltage deviation as the input and displacement regulator outputting displacement change; the inner loop is a speed loop, with displacement deviation as the input, used to adjust the stepper motor's operating speed.
2. The arc fault generating device according to claim 1, characterized in that, The arc fault protector test circuit is also connected to the test circuit status detection module and the test circuit control module.
3. The arc fault generating device according to claim 1, characterized in that, Also includes: Contact state detection circuit, the contact state detection circuit including current limiting resistor R、 The DC power supply module, contactor KM1, and the contact state detection circuit are used to disengage from the arc generator when the first electrode and the second electrode are determined to be in a stable contact state. The control unit is also used to execute a detection closed-loop control mode when the contact state detection circuit contacts the arc generator. The detection closed-loop control mode calculates the voltage change as a feedback quantity and adjusts the relative movement speed of the two electrodes until the voltage between the two electrodes remains constant.
4. An arc fault occurrence control method, applicable to the arc fault occurrence device as described in claim 1, characterized in that, Including steps, The voltage sensor and the current sensor detect the voltage and current between the first electrode and the second electrode, respectively. The control unit receives signals from voltage and current sensors. Based on the detected voltage sensor signal, it determines the contact state between the first and second electrodes. When it determines that the first and second electrodes are in stable contact, it simulates arc generation. It also determines the arcing time based on the detection signals from the voltage and current sensors and adjusts the allowable inter-electrode voltage value of the arc generator accordingly. The control unit calculates the effective value U of the periodic voltage based on the voltage u detected by the voltage sensor, and the calculation satisfies 80%. U s > U >20V, and the ratio between the contact voltage and the line current is greater than the contact resistance. R jc The duration of the finite state, as the arcing time, U s The power supply voltage is used to enter the arc generation simulation stage when the contact state of the first electrode and the second electrode is stable. It also includes a PID closed-loop control step, including a voltage regulation loop, a displacement loop, and a speed loop. The voltage regulation loop is the outer loop, which takes the continuous arcing time deviation as input and outputs a given voltage value. The middle loop is a displacement loop, with voltage deviation as the input and displacement regulator outputting displacement change; the inner loop is a speed loop, with displacement deviation as the input, used to adjust the stepper motor's operating speed.
5. The arc fault occurrence control method according to claim 4, characterized in that, The device further includes: an arc fault protector test circuit, which is connected to a test circuit status detection module and a test circuit control module; Contact state detection circuit, the contact state detection circuit including current limiting resistor R、 The DC power supply module and contactor KM1 are provided. The contact status circuit control and monitoring module is used to control and detect the working status of KM1. The control method further includes the step of executing a detection closed-loop control mode when the contact state detection circuit contacts the arc generator. The detection closed-loop control mode is to calculate the voltage change as a feedback quantity and adjust the relative movement speed of the two electrodes until the voltage between the two electrodes remains constant.
6. The arc fault occurrence control method according to claim 4, characterized in that, When it is determined that the first electrode and the second electrode are in stable contact, the control unit controls the contact state detection circuit to disengage from the arc generator.