Multifunctional detection system for photovoltaic module direct current cable

Abstract

The invention relates to the technical field of photovoltaic power generation system detection, and discloses a multifunctional detection system for a photovoltaic module direct current cable, and the system comprises an input interface module which is used for being connected with the photovoltaic module direct current cable and inputting an obtained signal to a control core module; the control core module is used for receiving a signal transmitted by the input interface module and scheduling the detection function module cluster to execute various detection operations; and the detection function module cluster is used for completing polarity detection, insulation detection, voltage detection and discharge control. The equipment miniaturization and low power consumption are realized through the design of the composite switch, the operation efficiency is improved by integrating a multi-parameter collaborative detection mechanism, the operation safety is ensured by constructing a soft-hard collaborative protection system, and the real-time and reliable data is ensured by adopting a reinforced communication architecture. The industrial pain points of heavy equipment, dispersed functions, response lag, data misalignment and the like in the photovoltaic direct current system detection are solved on the whole.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation system detection, and in particular to a multifunctional detection system for a photovoltaic assembly DC cable. Background Art

[0002] As photovoltaic power generation systems evolve toward higher voltages and larger capacities, DC-side inspection and maintenance face new technical challenges. Photovoltaic arrays often experience hidden faults such as reverse polarity wiring and insulation breakdown under complex operating conditions. Traditional inspection methods are no longer able to meet the demands of efficient and accurate maintenance, especially in large-scale parallel configurations.

[0003] The existing testing system relies on a combination of discrete instruments such as multimeters and megohmmeters, requiring repeated disconnection and reconnection of cables for offline measurements. Polarity verification and insulation testing cannot be performed simultaneously, and multiple parallel systems require disconnection and testing one by one, which not only affects power generation efficiency but also increases the risk of misoperation. In the event of abnormal discharge, there is a lack of active pressure relief, and residual voltage poses a threat to personal safety. Test data relies on manual recording, making real-time and accuracy difficult to ensure. These shortcomings extend the construction period of photovoltaic power plants and increase operation and maintenance costs.

[0004] In response to the above problems, the present invention proposes a multifunctional detection system for photovoltaic module DC cables. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a multifunctional detection system for photovoltaic module DC cables, which solves the problems of multi-parameter integrated detection, rapid safety protection and intelligent data management of DC cables in high-voltage environments.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A multifunctional detection system for photovoltaic module DC cables, comprising:

[0007] The input interface module is used to connect to the DC cable of the photovoltaic module and input the acquired signal to the control core module;

[0008] A control core module, which is used to receive signals from the input interface module and schedule the detection function module cluster to perform various detection operations;

[0009] A detection function module cluster, which is used to perform polarity detection, insulation detection, voltage detection, and discharge control. It is provided with a measurement switch for realizing on-off selection of the detection path. The measurement switch is composed of an insulated gate bipolar transistor and a high-voltage reed relay;

[0010] A data processing module, which is used to process and store the detection data output by the detection function module cluster;

[0011] Human-computer interaction module, which is used to display detection information and provide an operation interface;

[0012] A security protection module, which is used to detect abnormal conditions in real time during system operation and implement protective measures;

[0013] The above modules communicate with each other through an isolated CAN bus. The communication protocol frame structure includes a frame header, a length field, a command word, a data field and a cyclic redundancy check code. The system detection cycle is no more than 200 milliseconds and the data refresh rate is no less than 5 Hz.

[0014] Preferably, the input interface module includes:

[0015] Dual-channel foolproof interface structure to prevent wiring errors and achieve reliable connection with DC cables of different polarities;

[0016] Shielding processing unit for suppressing electromagnetic interference;

[0017] A dual-channel connection structure is used to simultaneously connect to two groups of photovoltaic module DC cables and transmit the collected signals to the detection function module cluster for parallel detection;

[0018] The polarity indicator device is used to send a green indication signal when the detection function module cluster determines that the positive and negative poles are connected correctly, and send a red indication signal when the connection is determined to be incorrect.

[0019] Preferably, the control core module includes:

[0020] The task scheduling unit executes the dual-channel time division multiplexing scheduling strategy and activates the two detection channels alternately according to the preset flag bits.

[0021] Preferably, in the detection function module cluster:

[0022] Polarity detection uses a dynamic threshold comparator with a hysteresis voltage set to 30-100mV;

[0023] The insulation test includes a high voltage application device and a leakage current detection circuit;

[0024] Voltage detection adopts four-wire measurement method;

[0025] The discharge control includes a programmable resistor network and an external resistor recognition module.

[0026] Preferably, the insulation test applies a test voltage in a step-by-step manner by a high voltage application device, wherein the voltage is increased by 400-600 volts every 100±20 milliseconds in the initial stage and by 150-250 volts every 100±20 milliseconds when approaching the target voltage;

[0027] The leakage current detection circuit in the insulation detection is used to measure the response current, and the data processing module calculates the insulation resistance value based on the ratio of voltage to leakage current and deducts the reference resistance value set by the system.

[0028] Preferably, the programmable resistor network in the discharge control comprises a basic resistor unit consisting of five resistors with a resistance of 90-110 ohms and a power of 180-220 watts connected in series, and the network is dynamically configured through a relay or controllable switch array to achieve programmable control;

[0029] The external resistance identification module in the discharge control calculates the resistance of the connected external resistor by measuring the ratio of the open circuit voltage to the short circuit current, and feeds the identification result back to the control core module for matching the corresponding discharge parameters.

[0030] Preferably, the data processing module includes:

[0031] Digital filtering unit, which performs noise suppression and signal stabilization based on a combination of sliding average and Kalman filter algorithms;

[0032] The data compression unit compresses the continuous detection data using differential coding, with a compression rate of no less than 60%;

[0033] A data storage unit, used to store the detection data in the internal memory of the tooling equipment;

[0034] The data export interface is used to export the detection data in the form of files to a portable storage device.

[0035] Preferably, the human-computer interaction module includes:

[0036] Touch display unit, the display interface includes a polarity status display area, a voltage data display area, an insulation resistance curve display area and a function control button area;

[0037] The operation recording unit can record user operation logs. The log information includes timestamp, event level and corresponding operation description, and can be searched by condition classification.

[0038] Preferably, the security protection module includes:

[0039] Hardware protection layer, used to detect when the system detects that the current change rate exceeds 10 6 The arc extinguishing mechanism is triggered when the ampere per second;

[0040] The software protection layer has triple-module redundancy verification capability and performs majority voting logic judgment on key operation instructions to improve fault tolerance.

[0041] The present invention provides a multifunctional detection system for photovoltaic module DC cables. It has the following beneficial effects:

[0042] 1. The present invention realizes dynamic path switching in high-voltage scenarios by adopting a composite switch design of IGBT and high-voltage reed relay. Compared with the traditional mechanical relay solution, it significantly reduces the size of the equipment and reduces energy loss, making the detection equipment portable and easy to carry and use on site.

[0043] 2. The present invention integrates a collaborative detection mechanism for polarity identification, insulation testing, and voltage monitoring. Combined with an expandable discharge module, on-site personnel can complete full-project testing without switching equipment. It supports external customized discharge components, greatly simplifying the installation and commissioning process of photovoltaic power stations.

[0044] 3. The present invention constructs a dual protection mechanism of hardware rapid response and software redundancy check. When an abnormality is detected, multi-level linkage protection is immediately activated. At the same time, erroneous instructions are filtered through the three-machine voting mechanism, effectively preventing misoperation and ensuring operational safety in high-voltage environments.

[0045] 4. The present invention adopts a communication architecture with an isolated bus and enhanced verification protocol to ensure the reliability of data transmission across modules. System-level timing control realizes real-time synchronous update of detection parameters, enabling operation and maintenance personnel to accurately grasp equipment dynamics and improve fault diagnosis efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a framework flow chart of the system of the present invention;

[0047] Figure 2 This is a framework diagram of the input interface module of the present invention;

[0048] Figure 3 This is a framework diagram of the data processing module of the present invention;

[0049] Figure 4 This is a framework diagram of the human-computer interaction module of the present invention;

[0050] Figure 5 This is a framework diagram of the security protection module of the present invention. DETAILED DESCRIPTION

[0051] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the present specification. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0052] Please see the attached Figure 1 The embodiment of the present invention provides a multifunctional detection system for a photovoltaic module DC cable, comprising:

[0053] Please see the attached Figure 2 , an input interface module, which is used to connect to the DC cable of the photovoltaic module and input the acquired signal to the control core module;

[0054] In this embodiment, the input interface module is responsible for the physical connection between the PV module DC cable and the detection system, as well as signal acquisition. This module design has several key technical features to ensure the efficiency, reliability, and anti-interference of the access process.

[0055] First, the input interface module features a dual-channel foolproof interface structure, which prevents wiring errors through a specific physical connection design. This foolproof interface ensures that DC cables of different polarities are correctly connected and prevents misconnection. This design ensures correct cable polarity through a specific plug, terminal block, and foolproof structure. This feature effectively reduces user errors and improves system reliability.

[0056] To further enhance the system's interference resistance, the input interface module is equipped with a shielded processing unit. This unit, through its conductive housing and grounding design, suppresses electromagnetic interference from the environment, preventing external noise from affecting signal acquisition. Its physical design relies primarily on the isolation between the external shielding layer and the internal high-frequency circuitry, ensuring high-quality signal transmission.

[0057] Furthermore, the input interface module utilizes a dual-channel connection structure. This structure allows simultaneous access to two sets of PV panel DC cables, enabling the system to process multiple signal inputs in parallel. Specifically, this dual-channel design provides the system with parallel testing capabilities, effectively shortening testing cycles and improving overall testing efficiency. In practice, users can connect cables from multiple PV panels at once, and the system will perform parallel testing on both sets of cables, reducing overall system testing time.

[0058] The polarity indicator in the input interface module plays a crucial role when connecting the DC cable to a photovoltaic module. This device monitors the cable's polarity connection in real time, determining whether the positive and negative poles are connected incorrectly and providing feedback to the user through different colored indicator lights. When the system detects a correct connection, the polarity indicator emits a green signal to alert the user. If the connection is incorrect, a red signal prompts the user to reconnect the cables. This indicator operates based on the circuit's polarity detection module, using a dynamic threshold comparator to determine the signal's polarity and then determine whether the connection is correct based on a set threshold.

[0059] After the signal is received and processed by the above modules, it is transmitted to the control core module. The control core module schedules tasks based on the input signal and instructs the detection function module cluster to perform the corresponding detection operation.

[0060] Polarity detection algorithm: The core of polarity detection is a dynamic threshold comparator. A hysteresis voltage (typically in the range of 30-100mV) is set, and the polarity of the connection is determined by dynamically comparing the voltage signal with this hysteresis voltage value. If the voltage value is above the threshold and remains stable, it is determined to be a positive connection; if the voltage value is below the threshold, it is determined to be a negative connection.

[0061] Determine polarity: V measured vs.V threshold

[0062] Among them, V measured is the actual measured voltage, V threshold is the set hysteresis voltage.

[0063] The shielded processing unit uses high-frequency filtering technology to suppress electromagnetic interference. By designing a high-frequency filtering circuit (such as an LC filter) between the input interface and the control module, it can effectively filter out high-frequency interference signals and ensure the purity of the detection signal.

[0064] Where Z is impedance, R is resistance, ω is angular frequency, L is inductance, and C is capacitance.

[0065] The connection between the input interface module and other modules relies on physical signal transmission and control signal scheduling. Specifically, the input interface module connects to the PV panel DC cable via a cable interface, and the collected signals are transmitted to the core control module via an electrical interface. Simultaneously, the polarity indicator in the input interface module communicates with the core control module in real time, providing connection status information to the user through a circuit feedback mechanism.

[0066] When the core control module receives the signal, it communicates with the cluster of detection modules via the control bus, instructing the system on specific detection operations. The detection module's results are further processed and stored by the data processing module. All information is displayed and interacted with via the human-computer interaction module, allowing users to view detection results and perform control operations via the touchscreen display unit.

[0067] This implementation ensures reliable connection and accurate testing of PV module DC cables. The foolproof interface design prevents wiring errors and ensures reliable testing. The shielded processing unit effectively resists electromagnetic interference, improving the system's anti-interference capabilities and ensuring accurate signal acquisition. Furthermore, the dual-channel design increases the efficiency of parallel testing and reduces the time and cost of on-site testing. A polarity indicator provides real-time feedback on connection status, helping users promptly identify wiring errors and ensuring the accuracy and reliability of test results.

[0068] Through the collaborative work of the above modules, the system not only has a high anti-interference ability, but also can realize parallel detection of multiple photovoltaic cables, greatly improving the detection efficiency and response speed.

[0069] The control core module is used to receive signals from the input interface module and schedule the detection function module cluster to perform various detection operations;

[0070] In this embodiment, the control core module serves as the system's scheduling hub, responsible for coordinating the execution of detection tasks by each functional module. The control core module includes a task scheduling unit that implements multi-task parallel processing through a dual-channel time-division multiplexing scheduling strategy. The specific implementation is as follows:

[0071] The task scheduling unit manages the activation status of the two detection channels using preset flags. When the input interface module transmits a signal to the control core module, the task scheduling unit first analyzes the signal type and generates a task queue based on the preset priority. The flag is implemented as a binary status register, and its status value is dynamically updated using the following formula:

[0072]

[0073] Among them, F ch Indicates the channel activation flag. The task scheduling unit triggers the scheduling cycle through timer interrupts, alternating the flag state within each cycle. The timer interrupt period is set to 100ms to match the system detection period to ensure real-time requirements.

[0074] The dual-channel time division multiplexing scheduling strategy is implemented through a time slice rotation algorithm. Each detection channel is assigned a fixed time slice. When the current time slice is exhausted, the task scheduling unit automatically switches to another channel. The time slice length T slice Determined by the following calculation:

[0075]

[0076] Where, T cycle Indicates the system detection period (≤200ms), N ch is the number of activated channels (value is 2). The algorithm ensures that each channel gets at least one execution opportunity in a single detection cycle.

[0077] The task scheduling unit establishes a physical connection with the detection module cluster via a control bus. When a channel is activated, the scheduling unit sends an enable signal to the corresponding detection module via the address decoding circuit and simultaneously transmits detection parameters via the data bus. The detection results are returned to the control core module via an interrupt and stored in the dual-port RAM for buffering.

[0078] During implementation, the scheduling strategy is implemented through a state machine. State transition conditions include: time slice exhaustion, detection task completion, abnormal event triggering, etc. The state machine contains three basic states: ready state, running state, and suspended state. The transition relationship between them is described by the following logical expression:

[0079]

[0080] Among them, E err Indicates abnormal event flag, T remain Counts the remaining time slice.

[0081] This implementation enables parallel management of dual detection channels, improving system resource utilization through time-division multiplexing. The scheduling algorithm, combined with the hardware timer, ensures timely completion of detection tasks without conflicts. The state machine design enhances the system's exception handling capabilities. When the security protection module triggers an exception, it immediately suspends the current task and executes the protection process.

[0082] A detection function module cluster, which is used to complete polarity detection, insulation detection, voltage detection and discharge control. It is equipped with a measurement switch to realize the on-off selection of the detection path. The measurement switch is composed of an insulated gate bipolar transistor and a high-voltage reed relay;

[0083] In this embodiment, a detection module cluster achieves a comprehensive status assessment of the PV module DC cable by collaborating across multiple detection paths. The detection module cluster includes a polarity detection unit, an insulation detection unit, a voltage detection unit, and a discharge control unit. Each unit dynamically configures the detection path using a measurement switch.

[0084] The polarity detection unit adopts dynamic threshold comparator design, and its hysteresis voltage range is set to 30-100mV. When the input voltage signal exceeds the positive threshold V th+ =V ref +ΔV is determined to be the positive electrode connected correctly, and when it is lower than the negative threshold V th- =V ref -ΔV is considered a polarity error, where V ref is the reference voltage, and ΔV is the hysteresis voltage. This design is implemented through a positive feedback circuit composed of an operational amplifier, which can effectively suppress misjudgments caused by signal jitter.

[0085] The insulation detection unit includes a high-voltage application device and a leakage current detection circuit. The high-voltage application device uses a step-by-step voltage boost strategy, initially increasing the voltage by 500V (±100V) every 100ms. When the voltage reaches 80% of the preset value, it switches to increasing by 200V (±50V) every 100ms. The voltage boost process is controlled by the following formula:

[0086]

[0087] Where, k1=5V / ms, k2=2V / ms, V offset is the transition voltage compensation value, t transition The leakage current detection circuit uses a high-precision transimpedance amplifier to convert the current signal into a voltage signal:

[0088] v out =i leak ·R f ;

[0089] Among them, R f The feedback resistor is 1MΩ (typical value), and the measurement resolution is 0.1μA. leak is the leakage current value, V out is the output voltage signal. The data processing module calculates the insulation resistance value according to the following formula:

[0090]

[0091] Where R cal The system calibration resistor (preset value 50kΩ) is used to eliminate the influence of the inherent impedance of the detection circuit. test is the applied test voltage.

[0092] The voltage detection unit adopts a four-wire measurement method, which is separated from the current excitation line by an independent voltage sampling line. When measuring, a constant current I is first applied. excite =10mA, then measure the voltage drop across the cable:

[0093] V real =V measured -I excite ·R lead ;

[0094] Where R lead is the lead resistance compensation value, obtained through open circuit calibration. This design controls the measurement error within ±0.5%. measured is the original measured voltage value, I excite is the excitation current value, V real The actual voltage value after compensation.

[0095] The discharge control unit includes a programmable resistor network and an external resistor identification module. The basic resistor network consists of five 100Ω±10%, 200W resistors connected in series, which can be combined into 32 equivalent resistance values ​​through the relay array. Discharge resistance value R discharge Dynamic configuration according to the following formula:

[0096]

[0097] Among them, S i Indicates the switch state of the i-th relay (0 / 1), R i The external resistance identification module measures the open circuit voltage V oc and short-circuit current I sc Calculate the external resistor value:

[0098]

[0099] Where α is the temperature compensation coefficient (typical value 0.0039 / °C), and ΔT is the ambient temperature change. The recognition result is fed back to the control core module via the SPI interface.

[0100] The measurement switch consists of an IGBT and a high-voltage reed relay. When the detection voltage is less than 1000V, the IGBT is used for path switching; when the voltage exceeds 1000V, it automatically switches to the reed relay. The switching logic is implemented by a voltage comparator:

[0101]

[0102] Where V detect To detect voltage value in real time, SW sel Select the signal for the switch, 0 means IGBT is selected, 1 means reed relay is selected.

[0103] This design reduces switching losses to 40% of traditional solutions while achieving a withstand voltage of DC3000V.

[0104] This implementation enables automatic switching and precise measurement of multiple parameters. A step-up voltage algorithm reduces test time while ensuring accuracy, and a four-wire measurement method effectively eliminates the effects of lead resistance. A programmable resistor network achieves precise control of the discharge process through dynamic configuration, while a temperature compensation algorithm reduces external resistor identification error to less than ±2%.

[0105] Please see the attached Figure 3 , a data processing module, which is used to process and store the detection data output by the detection function module cluster;

[0106] In this embodiment, the data processing module optimizes and manages the storage of test data through a multi-stage processing flow. The data processing module includes a digital filtering unit, a data compression unit, a data storage unit, and a data export interface. Each unit is connected in the order of data flow to form a processing chain.

[0107] The digital filter unit uses a combination of sliding average method and Kalman filter algorithm. k , first perform a sliding average calculation with a window size of 5:

[0108]

[0109] The result is then fed into the Kalman filter for state estimation:

[0110]

[0111] Where, is a priori estimate, K k is the Kalman gain, H=1 is the observation matrix, x k is the kth original sample value, z k The combined algorithm reduces the signal-noise variance to less than 28% of the original data.

[0112] The data compression unit adopts an improved differential encoding algorithm. n Perform first-order difference calculation: ΔD n =D n -D n-1 ;

[0113] Dynamic Huffman coding is used for the differential result, and the code table is generated based on the statistics of the first 1024 data samples. The compression rate meets the following requirements:

[0114]

[0115] Where L(·) represents the bit length of the data after encoding, η represents the compression rate, L(D i ) is the original data D i The coding length is fixed at 16 bits / sample, L(ΔD i ) is the difference data ΔD i The encoding length has a dynamic range of 4-12 bits.

[0116] The data storage unit uses NAND Flash memory and implements wear leveling through the FTL layer. The storage data structure consists of a 32-byte file header and a 512-byte data block. The file header fields include:

[0117] Timestamp (8 bytes, Unix millisecond format);

[0118] Channel ID (1 byte);

[0119] Data type (1 byte);

[0120] CRC check code (2 bytes).

[0121] The storage unit achieves real-time writing through a double buffering mechanism. When buffer A writes to the Flash, buffer B receives the new data, and the switching cycle is 50ms.

[0122] The data export interface uses the USB PD protocol and supports 3.0A current output. The export file format is a structured binary file, consisting of a file header, a data area, and an index area. The data area stores the filtered raw data in chronological order, while the index area records the starting offset of each test item.

[0123] Each unit is connected via a 32-bit data bus: the output of the filter unit is connected to the input of the compression unit, and the compressed data is written to the storage unit after verification. When the export command is triggered, the storage unit transfers the data in batches to the interface chip via the DMA channel. The exported file system format is exFAT, which supports single file storage of more than 4GB.

[0124] This implementation enables real-time processing and reliable long-term storage of test data. A two-stage filtering algorithm effectively suppresses random interference while preserving signal characteristics, and dynamic difference encoding significantly reduces storage space requirements. The structured file design supports rapid retrieval and analysis, while the exFAT format ensures compatibility for large amounts of data.

[0125] Please see the attached Figure 4 , a human-computer interaction module, which is used to display detection information and provide an operation interface;

[0126] In this embodiment, the human-computer interaction module realizes the visualization presentation of detection information and user operation management through a graphical interface. The human-computer interaction module includes a touch display unit and an operation recording unit, which work together through an event-driven mechanism.

[0127] The touch display unit uses a 7-inch capacitive touch screen (resolution 800×480), and the display interface is divided into four functional areas. The polarity status display area uses LED icons to reflect the connection status in real time: a green circular icon is displayed when the polarity is correct, and a red cross icon is displayed when the polarity is incorrect. The icon color value is calculated using the following formula:

[0128]

[0129] Where V th =0.1V is the polarity judgment threshold. The voltage data display area is presented in the form of a digital meter with a refresh rate of not less than 5Hz and a numerical display accuracy of 0.1V.

[0130] The insulation resistance curve display area uses a sliding window mechanism to draw a real-time curve. The curve data point spacing d is determined by the following formula:

[0131]

[0132] Where W = 600px is the width of the display area, N = 50 is the maximum number of data points, and T = 2s is the time constant. This algorithm achieves a smooth scrolling effect of the curve.

[0133] The operation logging unit uses a circular buffer to store log entries. Each record contains the following fields:

[0134] Timestamp (32-bit Unix time, precision 0.1ms);

[0135] Event level (1 byte, 0-3 correspond to debug, information, warning, and error respectively);

[0136] Operation description (variable-length string, UTF-8 encoding).

[0137] The search function is implemented by establishing a B+ tree index, where the index key is a composite value of the timestamp and the event level. The search response time meets the following requirements:

[0138] t response ≤k·log2(N)+C;

[0139] Where k = 0.2 ms, C = 5 ms is the fixed overhead, and N is the total number of log entries.

[0140] In terms of physical connections, the touch display unit is connected to the main control chip via the RGB interface, and the touch signal is transmitted via the I2C bus. The operation recording unit uses an independent FRAM memory (capacity 1MB) and communicates with the main processor via the SPI interface.

[0141] The interface update process first obtains detection data from the control core module and generates display elements after coordinate transformation. When the user triggers a capacitive touch event, the touch coordinates are calculated using the following formula:

[0142]

[0143] Where, X raw ,Y raw is the original AD sampling value, X min / max ,Y min / max is the calibration parameter, W and H are the actual pixel sizes of the screen.

[0144] This implementation enables real-time visualization of detection information and operation traceability. A dynamic curve drawing algorithm fully displays data trends within a limited display area, while a touch coordinate calibration formula eliminates the impact of individual device differences on operational accuracy. A log indexing structure ensures efficient retrieval of massive operation records.

[0145] Please see the attached Figure 5 , a security protection module, which is used to detect abnormal conditions in real time during system operation and execute protection measures;

[0146] In this embodiment, the security protection module ensures system operation security through a dual protection mechanism of hardware and software. The security protection module includes a hardware protection layer and a software protection layer, which work together to achieve anomaly detection and rapid response.

[0147] The hardware protection layer uses a high-speed current sampling circuit (sampling rate 1MHz) to monitor current changes in real time. When the current change rate exceeds the threshold, the arc extinguishing mechanism is immediately triggered. Calculated by the following formula:

[0148]

[0149] Where, I n is the current sampling current value (unit: ampere), and Δt=1μs is the sampling interval. When the protection circuit triggers the following actions within 500ns:

[0150] Cut off the main power circuit (response time ≤ 100ns);

[0151] Activate the magnetic blowout device (driving voltage DC24V);

[0152] Release the energy stored in the buffer capacitor (discharge resistor 50Ω).

[0153] The software protection layer uses a triple modular redundancy (TMR) architecture to verify key instructions. Three independent processors execute the same task simultaneously, and the output instructions are determined by majority voting logic:

[0154]

[0155] Voting cycle T vote =10ms, with synchronization error controlled within ±1μs. Each processor uses a different clock source (main frequency 50MHz±0.1%), and cross-checking eliminates common-mode faults.

[0156] In terms of physical connections, the hardware protection layer is directly connected in parallel with the power circuit and sends fault signals to the control core via optocouplers. The three processors in the software protection layer are interconnected via a crossbar switch matrix, and the data bus is configured with parity bits.

[0157] The exception handling process begins with the hardware protection layer detecting a sudden current change, which then triggers the following chain reaction:

[0158] The hardware protection circuit cuts off the main circuit within 1μs;

[0159] Send an interrupt signal to the software protection layer (highest priority);

[0160] The triple-module redundant system enters safe mode and stops all non-essential tasks;

[0161] Display the fault code on the human-machine interface (response time ≤ 50ms).

[0162] This implementation achieves microsecond-level fault response and system protection. The hardware protection layer's differential detection algorithm accurately identifies arc characteristics, while software redundancy improves fault tolerance to 99.999%. Optocoupler isolation ensures that power circuit faults do not affect control system stability.

[0163] The above modules communicate with each other through an isolated CAN bus. The communication protocol frame structure includes a frame header, a length field, a command word, a data field and a cyclic redundancy check code. The system detection cycle is no more than 200 milliseconds and the data refresh rate is no less than 5 Hz.

[0164] Working Principle: When the DC cable from a PV panel is connected to the system, the input interface module first performs the physical connection and signal input tasks. This module features a dual-channel, foolproof interface structure, ensuring correct connection of cables of varying polarity. A polarity indicator provides real-time feedback on the connection status: a green signal indicates correct polarity; a red warning indicates an incorrect connection. Its internal shielding processing unit effectively suppresses potential electromagnetic interference in the field, ensuring stable sampling signals.

[0165] Upon receiving the input signal, the system's core control module is immediately activated. Its built-in task scheduling unit utilizes a dual-channel time-division multiplexing strategy, alternating between two detection channels based on flags, enabling parallel testing of multiple PV panels. The control core issues specific testing commands to lower-level detection modules and coordinates result reporting and subsequent processing.

[0166] During the detection phase, the detection function module cluster is activated to complete tasks such as polarity detection, voltage detection, insulation detection, and discharge control:

[0167] Polarity detection is achieved through a dynamic threshold comparator, with a hysteresis voltage of 30-100mV set to suppress false triggering;

[0168] Voltage detection uses a high-precision four-wire measurement method to avoid errors introduced by lead resistance;

[0169] Insulation testing is performed by providing a stepped voltage with a high voltage application device and performing response measurement in conjunction with a leakage current detection circuit;

[0170] The system calculates the insulation resistance value based on the ratio of leakage current to applied voltage, and automatically deducts the preset reference resistance to obtain a valid measurement result;

[0171] The discharge control part can perform fast discharge operations based on the built-in programmable resistor network. At the same time, if an external resistor is connected, the resistor identification module can automatically detect its resistance value and match the corresponding parameters for adaptation.

[0172] All raw data and intermediate results generated during the testing process are aggregated into the data processing module. This module not only smoothes and stabilizes the signal through filtering algorithms at the front end but also significantly compresses the data through differential encoding before storage, saving storage space. The compressed data is stored in the device's internal memory and can be exported at any time for verification or analysis.

[0173] The human-computer interaction module provides an intuitive and flexible operation and display interface. The touchscreen display not only displays test results and insulation resistance curves, but also provides convenient control areas. The system also logs all operations, including time, event level, and operation content, facilitating later management and traceability.

[0174] The entire detection process operates under the protection of safety mechanisms. The system monitors current changes in real time and, when a sharp current fluctuation is detected, immediately extinguishes any arcing through hardware mechanisms. Software also uses triple-module redundant logic to determine critical control instructions, enhancing system reliability in interference environments.

[0175] Each module achieves high-speed, stable communication via an isolated CAN bus. The protocol layer incorporates a complete data frame structure to ensure accurate and real-time data transmission between modules. With a refresh rate of no less than 5Hz and a detection cycle of no more than 200ms, this fully meets the needs of real-time on-site testing.

[0176] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A multifunctional detection system for photovoltaic module DC cables, characterized in that: include: The input interface module is used to connect to the DC cable of the photovoltaic module and input the acquired signal to the control core module; A control core module, which is used to receive signals from the input interface module and schedule the detection function module cluster to perform various detection operations; A detection function module cluster, which is used to perform polarity detection, insulation detection, voltage detection, and discharge control. It is provided with a measurement switch for realizing on-off selection of the detection path. The measurement switch is composed of an insulated gate bipolar transistor and a high-voltage reed relay; A data processing module, which is used to process and store the detection data output by the detection function module cluster; Human-computer interaction module, which is used to display detection information and provide an operation interface; A security protection module, which is used to detect abnormal conditions in real time during system operation and implement protective measures; The above modules communicate with each other through an isolated CAN bus. The communication protocol frame structure includes a frame header, a length field, a command word, a data field and a cyclic redundancy check code. The system detection cycle is no more than 200 milliseconds and the data refresh rate is no less than 5 Hz.

2. A multifunctional detection system for photovoltaic module DC cables according to claim 1, characterized in that: The input interface module includes: Dual-channel foolproof interface structure to prevent wiring errors and achieve reliable connection with DC cables of different polarities; Shielding processing unit for suppressing electromagnetic interference; A dual-channel connection structure is used to simultaneously connect to two groups of photovoltaic module DC cables and transmit the collected signals to the detection function module cluster for parallel detection; The polarity indicator device is used to send a green indication signal when the detection function module cluster determines that the positive and negative poles are connected correctly, and send a red indication signal when the connection is determined to be incorrect.

3. The multifunctional detection system for photovoltaic module DC cables according to claim 1, characterized in that: The control core module includes: The task scheduling unit executes the dual-channel time division multiplexing scheduling strategy and activates the two detection channels alternately according to the preset flag bits.

4. The multifunctional detection system for photovoltaic module DC cables according to claim 1, characterized in that: In the detection function module cluster: Polarity detection uses a dynamic threshold comparator with a hysteresis voltage set to 30-100mV; The insulation test includes a high voltage application device and a leakage current detection circuit; Voltage detection adopts four-wire measurement method; The discharge control includes a programmable resistor network and an external resistor recognition module.

5. The multifunctional detection system for photovoltaic module DC cables according to claim 4, characterized in that: The insulation test is performed by applying a test voltage in a step-by-step manner using a high voltage application device, wherein the voltage is increased by 400-600 volts every 100±20 milliseconds in the initial stage and by 150-250 volts every 100±20 milliseconds when approaching the target voltage; The leakage current detection circuit in the insulation detection is used to measure the response current, and the data processing module calculates the insulation resistance value based on the ratio of voltage to leakage current and deducts the reference resistance value set by the system.

6. The multifunctional detection system for photovoltaic module DC cables according to claim 4, characterized in that: The programmable resistor network in the discharge control includes a basic resistor unit consisting of five resistors with a resistance of 90-110 ohms and a power of 180-220 watts connected in series. The network is dynamically configured through a relay or controllable switch array to achieve programmable control; The external resistance identification module in the discharge control calculates the resistance of the connected external resistor by measuring the ratio of the open circuit voltage to the short circuit current, and feeds the identification result back to the control core module for matching the corresponding discharge parameters.

7. The multifunctional detection system for photovoltaic module DC cables according to claim 1, characterized in that: The data processing module includes: Digital filtering unit, which performs noise suppression and signal stabilization based on a combination of sliding average and Kalman filter algorithms; The data compression unit compresses the continuous detection data using differential coding, with a compression rate of no less than 60%; A data storage unit, used to store the detection data in the internal memory of the tooling equipment; The data export interface is used to export the detection data in the form of files to a portable storage device.

8. The multifunctional detection system for photovoltaic module DC cables according to claim 1, characterized in that: The human-computer interaction module includes: Touch display unit, the display interface includes a polarity status display area, a voltage data display area, an insulation resistance curve display area and a function control button area; The operation recording unit can record user operation logs. The log information includes timestamp, event level and corresponding operation description, and can be searched by condition classification.

9. The multifunctional detection system for photovoltaic module DC cables according to claim 1, characterized in that: The security protection module includes: Hardware protection layer, used to detect when the system detects that the current change rate exceeds 10 6 The arc extinguishing mechanism is triggered when the ampere per second; The software protection layer has triple-module redundancy verification capability and performs majority voting logic judgment on key operation instructions to improve fault tolerance.

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