A power converter anomaly detection and protection method

Abstract

The application discloses a power converter abnormality detection and protection method, relates to the technical field of mine intrinsic safety power protection, is suitable for the combustible and explosive environment in a coal mine, and realizes the conversion of three ib-grade intrinsic safety input into three ia-grade intrinsic safety output. The method synchronously collects each input and output electric parameter and core module temperature through a sampling circuit and a main control unit, realizes real-time monitoring of the buffer starting, voltage limiting, current limiting, electrical isolation and intrinsic safety grade loop state, completes abnormality determination according to the threshold value of GB / T3836.4 standard, and performs graded protection according to the abnormality grade: first-grade dynamic adjustment of correction parameters, second-grade single-path shutdown of isolation failure, and third-grade power-off latching. Meanwhile, the method has the functions of buffer starting special protection, intrinsic safety grade real-time verification, fault record latching and uploading, the first and second grade protections are automatically restored after the fault is eliminated, and the third grade protection supports manual / remote reset.

Description

Technical Field

[0001] This invention relates to the field of intrinsically safe power supply protection technology for mining, and in particular to a method for detecting and protecting power converter malfunctions. Background Technology

[0002] Intrinsically safe power converters for mining are specially designed for power conversion in flammable and explosive environments such as underground coal mines. Through circuit power limiting and electrical isolation designs, they ensure that the electrical sparks and thermal effects generated by the equipment under normal operation and fault conditions are insufficient to ignite the surrounding explosive mixture, thus possessing intrinsically safe explosion-proof performance.

[0003] Intrinsically safe power converters for mining are the core power supply units for monitoring, communication, and sensing equipment in the flammable and explosive environment of underground coal mines. They need to convert IB-level intrinsically safe inputs into IA-level intrinsically safe outputs, and have extremely high requirements for power supply safety and continuity.

[0004] Currently, the three-input, three-output intrinsically safe power converters used underground only collect basic voltage and current, without simultaneously monitoring temperature, soft start, voltage and current limiting, electrical isolation, and intrinsic safety level determination circuits. This results in significant detection blind spots, making it impossible to identify latent faults such as intrinsic safety degradation, isolation failure, and soft start anomalies in advance. Furthermore, many adopt a "one-size-fits-all" protection approach where a single channel failure leads to a complete power outage, disrupting the continuous power supply to critical underground equipment. They are also prone to unnecessary shutdowns due to momentary disturbances. Therefore, mining intrinsically safe power converters suffer from incomplete anomaly detection, simplistic protection strategies, and an inability to verify intrinsic safety levels in real time, easily leading to safety and power supply failures. Summary of the Invention

[0005] The purpose of this invention is to provide a method for detecting and protecting abnormalities in a power converter in order to solve the above-mentioned problems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for anomaly detection and protection of a power converter is provided, applicable to an intrinsically safe power converter used in flammable and explosive environments in underground coal mines. The converter converts three intrinsically safe power inputs of IB level into three intrinsically safe power outputs of IA level. The anomaly detection and protection method includes the following steps: S1. Multi-parameter synchronous acquisition: Through the built-in sampling circuit and main control unit, the input voltage and current of each channel, the output voltage and current of each channel, and the operating temperature of the internal core module are collected in real time. At the same time, the working status of the soft start circuit, voltage and current limiting circuit, electrical isolation module and intrinsic safety level determination circuit are monitored simultaneously. S2. Threshold comparison and anomaly judgment: The collected electrical and temperature parameters are compared in real time with the intrinsically safe thresholds of level ia, the normal operating range thresholds, and the fault warning thresholds preset according to the GB / T3836 series standards. When the parameters exceed the limits, the energy limiting circuit is abnormal, the soft start fails to meet the standard, the temperature exceeds the upper limit, or the electrical isolation fails, the corresponding channel or the whole machine is judged to be in an abnormal state. S3. Graded protection execution: Graded protection is executed according to the type, severity and intrinsic safety impact level of the anomaly. The power supply continuity is maintained while ensuring that the output energy does not exceed the ia safety limit, so as to avoid the shutdown of the whole machine or the explosion of an explosive environment caused by a single fault. S4. Fault Handling and Recovery: Real-time latching, recording, and uploading of parameters for all abnormal states, enabling traceable, monitorable, and tiered recovery of faults.

[0007] Preferably, the abnormal state includes at least one of the following: overvoltage, undervoltage, overcurrent, short circuit, overtemperature, soft start failure, intrinsic safety degradation, voltage limiting circuit failure, current limiting circuit failure, and electrical isolation abnormality.

[0008] Preferably, real-time data acquisition includes: The voltage and current of the three input power supplies are collected independently. The voltage, current, and loop impedance of the three output ia-level power supplies are collected independently. Every 10ms to 100ms, a round of full parameter acquisition, threshold comparison, and anomaly detection is completed.

[0009] Preferably, the graded protection actions include: Level 1 protection: Performs dynamic current limiting, real-time voltage limiting, and reduces PWM duty cycle to correct abnormal parameters without interrupting output; Level 2 protection: shuts down the corresponding single output that malfunctions, while maintaining normal power supply to the other outputs; Level 3 protection: Immediately disconnects the entire input power supply, latches the fault status, and prohibits automatic restart.

[0010] Preferably, it also includes soft start detection and protection: after power-on, the voltage rise slope and surge current peak value during the soft start phase are detected in real time; if the slope is too fast or the peak value exceeds the threshold, the soft start abnormality is immediately determined and the output is cut off to prevent damage to the upstream power supply and downstream load.

[0011] Preferably, it also includes intrinsic safety level anomaly detection: real-time monitoring of the working status of the voltage limiting circuit, current limiting circuit, and isolation module; when the energy limiting circuit is detected to be in failure and the ia-level safe energy output cannot be guaranteed, the intrinsic safety ia-level failure is determined and the three-level protection is executed.

[0012] Preferably, it also includes fault recording and uploading: latching the fault type, occurrence time, fault parameter value, and fault channel; and uploading the fault information to the host computer or the downhole intrinsically safe monitoring system via serial port, RS485, or intrinsically safe bus.

[0013] Preferably, it also includes automatic fault recovery: after the third-level protection latch is locked, manual reset is supported only; after the abnormal cause of the first / second-level protection is eliminated, normal output is automatically restored.

[0014] Preferably, the preset threshold, current limit, voltage limit and energy limit are all set according to the intrinsic safety standard GB / T3836.4 to ensure that the output energy does not exceed the safety limit of level ia under any operating condition.

[0015] Preferably, the anomaly detection and protection method is specifically designed for mining intrinsically safe three-input three-output power converters that convert IB-level inputs to IA-level outputs.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This invention adopts a multi-parameter synchronous acquisition mechanism, independently acquiring three input and output electrical parameters and core module temperature, and synchronously monitoring the status of soft start, voltage and current limiting, electrical isolation and intrinsic safety level determination circuits. With a high-frequency acquisition cycle of 10ms to 100ms, it comprehensively covers various anomalies such as overvoltage, undervoltage, overcurrent, short circuit, overtemperature, and intrinsic safety level degradation, eliminating detection blind spots and achieving rapid and accurate judgment of abnormal states. 2. This invention implements three levels of protection based on the severity of the abnormality. Level 1 protection dynamically adjusts the output without interruption, Level 2 protection shuts down a single circuit without affecting the power supply of the whole machine, and Level 3 protection cuts off the entire machine to eliminate safety risks. Under the premise of strictly complying with the GB / T3836.4 standard and ensuring that the output energy does not exceed the safety limit of level ia, it avoids the shutdown of the whole machine caused by a single fault and is suitable for the continuous power supply needs of underground coal mines. 3. This invention adds a special detection and protection for slow start, accurately controls the voltage slope and surge current, and prevents damage to the upstream power supply and downstream load; it also adds real-time monitoring of intrinsic safety level, which immediately triggers the highest level of protection once the energy limiting circuit or isolation module fails, thereby preventing the energy from exceeding the limit and igniting flammable and explosive environments from the source, and greatly improving the intrinsic safety level of mining equipment. 4. This invention latches information such as anomaly type, time, parameters, and channel in real time, without loss of data upon power failure. It uploads this information to the host computer and downhole monitoring system via serial port, RS485, or intrinsically safe bus, enabling fault traceability and remote monitoring. The invention also optimizes the hierarchical recovery mechanism, with automatic recovery for Level 1 and Level 2 protection and manual / remote reset for Level 3 protection, reducing on-site intervention in the well and lowering maintenance difficulty and safety risks. Attached Figure Description

[0017] Figure 1 A flowchart of an anomaly detection and protection method according to an embodiment of the present invention is shown. Figure 1 ; Figure 2 A flowchart of an anomaly detection and protection method according to an embodiment of the present invention is shown. Figure 2 . Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1 Please see Figure 1 - Figure 2 This embodiment provides a method for detecting and protecting abnormalities in a power converter, applicable to an intrinsically safe power converter used in the flammable and explosive environment of an underground coal mine. This converter is specifically designed to convert three intrinsically safe power inputs of IB level into three intrinsically safe power outputs of IA level. The IB level input power supply has a voltage range of 12V to 24V and a current range of 0 to 5A. The IA level output power supply has a voltage range of 5V to 12V and a current range of 0 to 2A. The output energy strictly complies with the IA level limits (energy ≤ 20μJ) specified in the GB / T3836.4 intrinsically safe standard. The abnormality detection and protection method specifically includes the following steps: Step 1: Multi-parameter synchronous acquisition: Through the built-in sampling circuit and main control unit, the input voltage and current of each channel, the output voltage and current of each channel, and the operating temperature of the internal core module are acquired in real time. At the same time, the working status of the soft start circuit, voltage and current limiting circuit, electrical isolation module and intrinsic safety level determination circuit are monitored simultaneously. Real-time data collection includes: The voltage and current of the three input power supplies are collected independently. The voltage, current, and loop impedance of the three output ia-level power supplies are collected independently. Every 10ms to 100ms, a round of full parameter acquisition, threshold comparison, and anomaly detection is completed.

[0020] Specifically, the power converter integrates three independent sampling circuits, a temperature sensor, and a loop status monitoring module. It establishes bidirectional communication with the main control unit (using an STM32F407 microcontroller, intrinsically safe, and adaptable to downhole operating environments of -40℃ to 60℃) to achieve synchronous acquisition of multiple parameters. Input parameter acquisition: Input current is acquired through a precision shunt resistor (accuracy 0.1%) connected in series in each input loop, and input voltage is acquired through a voltage divider circuit connected in parallel across the input terminals. The acquisition accuracy reaches ±0.5%, ensuring the accuracy of the acquired data. Output parameter acquisition: The three ia-level output power supplies are acquired independently. The output voltage is acquired through a voltage sensor, the output current is acquired through a current sensor, and the output circuit impedance is acquired through an impedance detection circuit to determine in real time whether there are problems such as poor contact or short circuit precursors in the output circuit. Temperature acquisition: A PT100 temperature sensor is attached to the surface of the core module (such as the PWM control module and power transistor module) inside the power converter to acquire the operating temperature of the core module in real time. The acquisition range is -40℃~125℃, with an accuracy of ±1℃. Circuit status monitoring: Through voltage comparators, logic gate circuits, etc., the working status of the soft start circuit, voltage and current limiting circuit, electrical isolation module (using intrinsically safe isolation transformer, isolation voltage ≥1000V) and intrinsic safety level determination circuit are monitored synchronously, and the on / off status and signal abnormalities of each circuit are captured in real time.

[0021] In this step, a full-parameter acquisition, data filtering, and signal transmission are completed every 50ms to ensure that abnormal states can be captured in a timely manner, while avoiding excessive load on the main control unit due to excessive acquisition frequency, thus balancing detection timeliness and equipment stability.

[0022] Step 2: Threshold Comparison and Anomaly Judgment: The collected electrical and temperature parameters are compared in real time with the intrinsically safe thresholds of level ia, normal operating range thresholds, and fault warning thresholds preset according to the GB / T3836 series standards. When parameters exceed the limits, the energy limiting circuit is abnormal, the soft start fails to meet the standard, the temperature exceeds the upper limit, or the electrical isolation fails, the corresponding channel or the whole machine is judged to be in an abnormal state. Abnormal states include at least one of the following: overvoltage, undervoltage, overcurrent, short circuit, overtemperature, soft start failure, intrinsically safe level degradation, voltage limiting circuit failure, current limiting circuit failure, and electrical isolation abnormality. The preset thresholds, current limits, voltage limits, and energy limits are all set according to the GB / T3836.4 intrinsic safety standard to ensure that the output energy does not exceed the ia-level safety limit under any operating condition.

[0023] Specifically, the main control unit has three preset threshold values, all set according to the GB / T3836 series standards (GB / T3836.1-2010, GB / T3836.4-2010) and the intrinsically safe power supply design specifications for mining applications. These include: Intrinsic safety thresholds for Class ia: maximum output voltage 12.5V, maximum output current 2.1A, maximum output energy 20μJ, ensuring that the output energy does not exceed the Class ia safety limits under any operating conditions; Normal operating range thresholds: input voltage 12V~24V, input current 0~5A, output voltage 5V~12V, output current 0~2A, core module operating temperature -40℃~60℃, output circuit impedance 10Ω~100Ω; Fault warning thresholds: Input voltage 11V~12V (undervoltage warning), 24V~25V (overvoltage warning), input current 4.5A~5A (overcurrent warning), output voltage 4.5V~5V (undervoltage warning), 12V~12.5V (overvoltage warning), output current 1.8A~2A (overcurrent warning), core module temperature 55℃~60℃ (overtemperature warning).

[0024] The main control unit compares the collected electrical parameters, temperature parameters, and loop status signals with the above three types of thresholds in real time, and uses a "multi-parameter cross-validation" method to determine abnormal states. The specific determination logic is as follows: When a single parameter exceeds the threshold of the normal working range but does not reach the ia level safety threshold, it is judged as a warning state, which is a minor abnormality; When a single parameter exceeds the safety threshold of level ia, or when the energy limiting circuit (voltage limiting circuit, current limiting circuit) is abnormal, the soft start fails to meet the standard, the temperature exceeds the upper limit (>60℃), or the electrical isolation fails (isolation resistance <1MΩ), the corresponding channel or the whole machine is judged to be in a serious abnormal state. When the output circuit impedance is <10Ω (short circuit precursor) or >100Ω (poor contact), it is determined that the output circuit is abnormal. The abnormality type (short circuit or poor contact) should be further confirmed by combining the output current and voltage parameters.

[0025] Step 3: Graded protection execution: Based on the type, severity, and intrinsic safety impact level of the anomaly, three levels of protection actions are executed to maintain power supply continuity to the maximum extent possible while ensuring that the output energy does not exceed the ia safety limit, and to avoid a single fault causing the entire machine to shut down or igniting an explosive atmosphere. The specific protection actions are as follows; Graded protection actions include: Level 1 protection (minor abnormality / early warning status): When the detected parameters are within the fault early warning threshold range (such as input voltage 11.5V, output current 1.9A, core module temperature 58℃), dynamic current limiting and real-time voltage limiting operations are performed. By adjusting the PWM duty cycle (adjustment range 10%~90%), the abnormal parameters are corrected to the normal operating range. The entire process does not interrupt the output, ensuring the normal operation of the downhole load equipment. Level 2 protection (single channel serious anomaly): When an overvoltage (>12.5V), overcurrent (>2.1A), or short circuit (output impedance <5Ω) is detected in a certain output, or when an abnormality is detected in a certain input that cannot be corrected by the first-level protection, the corresponding single output with the abnormality is shut down (by controlling the MOSFET of that channel to shut down), while maintaining normal power supply to the other two outputs to prevent the abnormality from spreading to the whole machine; Level 3 protection (serious abnormality of the whole machine): When the core module temperature is detected to be >60℃, electrical isolation fails, intrinsic safety level is downgraded (cannot guarantee ia level energy output), or serious abnormalities occur in two or more channels at the same time, the three input power supplies are immediately cut off through the relay, the fault state is latched, and automatic restart is prohibited to prevent the output energy from exceeding the standard and igniting the explosive environment in the well.

[0026] It also includes soft start detection and protection: after power-on, the voltage rise slope and surge current peak value during the soft start phase are detected in real time; if the slope is too fast or the peak value exceeds the threshold, the soft start abnormality is immediately determined and the output is cut off to prevent damage to the upstream power supply and downstream load.

[0027] It also includes intrinsic safety level anomaly detection: real-time monitoring of the working status of the voltage limiting circuit, current limiting circuit, and isolation module; when the energy limiting circuit fails and cannot guarantee the ia level safe energy output, the intrinsic safety ia level is determined to be failed, and three-level protection is executed.

[0028] It also includes fault recording and uploading: latching the fault type, occurrence time, fault parameter value, and fault channel; and uploading the fault information to the host computer or the underground intrinsically safe monitoring system via serial port, RS485, or intrinsically safe bus.

[0029] Step 4: Fault Handling and Recovery: All abnormal states are latched, parameters are recorded and uploaded in real time to achieve traceable, monitorable and graded recovery of faults.

[0030] It also includes automatic fault recovery: the main control unit latches all abnormal states (early warning state, minor abnormality, and severe abnormality) in real time, records information such as abnormality type, occurrence time (accurate to milliseconds), abnormal parameter value, and fault channel, with a storage capacity of no less than 100 fault records, which are not lost after power failure; at the same time, the fault information is uploaded to the underground intrinsically safe monitoring system through the RS485 bus to realize fault traceability and remote monitoring.

[0031] The fault recovery mechanism is as follows: Under Level 1 protection, when the cause of the abnormality is eliminated (such as the input voltage returning to 12V~24V or the temperature dropping below 60℃), normal output will be automatically restored; under Level 2 protection, when the fault of the abnormal channel is eliminated (such as short circuit elimination or poor contact repair), the output of that channel will be automatically restored; after Level 3 protection latching, it can only be manually reset (via the intrinsically safe reset button on the power converter panel). After resetting, all parameters need to be retested, and normal power supply can only be restored after confirming that there are no abnormalities.

[0032] The anomaly detection and protection method is specifically designed for intrinsically safe three-input three-output power converters used in mining applications that convert IB-level inputs to IA-level outputs.

[0033] This technical solution comprehensively covers input and output electrical parameters, internal equipment temperature, and the status of each functional circuit through multi-parameter synchronous acquisition, eliminating the detection blind spots of existing technologies and ensuring that abnormal states can be captured in a timely and accurate manner. Through a graded protection mechanism, it avoids the shutdown of the entire machine due to a single minor anomaly, maximizing the continuity of underground power supply and ensuring the normal operation of critical equipment such as underground monitoring and communication. Fault latching, recording, and uploading enable fault traceability and remote monitoring, facilitating timely troubleshooting by maintenance personnel and reducing maintenance costs. The entire method strictly adheres to the GB / T3836 series standards, ensuring that the output energy does not exceed the ia-level safety limit under any operating condition, effectively preventing the safety hazards of igniting flammable and explosive environments underground, and improving the safety and reliability of intrinsically safe power converters for mining.

[0034] Example 2 This embodiment, based on Embodiment 1, adds a special detection and protection step for slow start-up. It addresses issues such as excessive surge current and rapid voltage rise that commonly occur when an intrinsically safe power converter for mining is powered on, further improving the reliability of the equipment and preventing damage to the upstream power supply and downstream load. The specific steps are as follows: In the multi-parameter synchronous acquisition step of Example 1, soft start parameter acquisition is added. After power-on (power-on time 0~500ms), the output voltage rise slope and surge current peak value during the soft start phase are detected in real time. In the S2 threshold comparison and anomaly judgment step, soft start anomaly judgment thresholds are added: voltage rise slope threshold ≤ 0.02V / ms, surge current peak value threshold ≤ 3A. In the S3 graded protection execution step, soft start anomaly protection logic is added.

[0035] The difference from Example 1 is as follows: Soft start parameter acquisition At the moment of power-on (0ms), the voltage rise slope (ΔU / Δt) is calculated by collecting the real-time change of the output voltage. At the same time, the peak value of the surge current is collected through the shunt resistor of the input circuit. The sampling frequency is increased to 20ms / time to ensure that the instantaneous anomalies in the soft start phase can be accurately captured.

[0036] Soft start anomaly detection The collected voltage rise slope and surge current peak value are compared with the preset soft start anomaly judgment threshold: if the voltage rise slope > 0.02V / ms (rise too fast) or the surge current peak value > 3A (peak value exceeds the standard), the soft start anomaly is immediately judged, and it is judged as a serious anomaly, triggering the corresponding protection action.

[0037] Soft start anomaly protection When a soft start anomaly is detected, immediately disconnect the corresponding output channel (if it is a single-channel soft start anomaly) or the entire machine output (if it is a multi-channel soft start anomaly), and latch the soft start anomaly state. Automatic recovery is prohibited. Maintenance personnel need to check the soft start circuit (such as soft start resistors and capacitors), troubleshoot the fault, and then manually reset to remove the protection and restart the machine.

[0038] Based on Embodiment 1, this technical solution adds a special detection and protection feature for slow start, specifically addressing the issues of excessive surge current and rapid voltage rise during power-up of intrinsically safe power converters for mining applications. This effectively prevents damage to the upstream input power supply due to excessive surge current, while also preventing downstream loads (such as underground sensors and controllers) from being damaged by voltage surges, further improving the reliability and lifespan of the power converter. The rapid detection and protection against slow start anomalies also prevents the output energy from exceeding the limit instantaneously due to slow start failure, further ensuring the safety of the flammable and explosive underground environment and compensating for the shortcomings of insufficient slow start anomaly detection in existing technologies.

[0039] Example 3 This embodiment, based on Embodiment 1, adds a specific detection step for intrinsically safe anomalies and optimizes the automatic fault recovery mechanism, further enhancing the intrinsic safety and ease of operation and maintenance of the equipment. It is suitable for deep underground coal mine operations with extremely high intrinsic safety requirements and significant maintenance challenges. The specific steps are as follows: Intrinsic safety level anomaly parameter collection In the multi-parameter synchronous acquisition step of Example 1, the acquisition of intrinsic safety level related parameters is added: real-time monitoring of the output voltage stability of the voltage limiting circuit (fluctuation range ≤ ±0.1V), the current response speed of the current limiting circuit (response time ≤ 10μs), the isolation resistance (≥1MΩ) and isolation voltage (≥1000V) of the electrical isolation module, and the acquisition of the logic signal of the intrinsic safety level determination circuit to confirm whether the ia level energy limit can be achieved normally.

[0040] Intrinsic safety level anomaly determination In threshold comparison and anomaly judgment, an intrinsic safety level anomaly judgment logic is added: when the output voltage fluctuation of the voltage limiting circuit is detected to be > ±0.1V, the response time of the current limiting circuit is > 10μs, the isolation resistance is < 1MΩ, the isolation voltage is < 1000V, or the logic signal of the intrinsic safety level judgment circuit is abnormal, resulting in the inability to guarantee the safe energy output of the ia level, the intrinsic safety ia level is judged to have failed, and the whole machine is immediately judged to be seriously abnormal, triggering the three-level protection.

[0041] Automatic fault recovery optimization In the fault handling and recovery steps of Example 1, the automatic fault recovery mechanism is optimized as follows: Level 1 protection automatic recovery: After the abnormal cause of Level 1 protection is eliminated, the main control unit performs 3 consecutive parameter checks (each check interval is 10ms) to confirm that the parameters are stable within the normal working range, and then automatically restores normal output without manual intervention; Secondary protection automatic recovery: After the fault of the abnormal channel is cleared, the main control unit delays for 300ms (to avoid repeated faults), and confirms that the abnormality has been cleared through two consecutive parameter checks, and then automatically restores the output of the channel; Level 3 protection recovery optimization: After the level 3 protection is latched, in addition to manual reset, a remote reset function is added. Maintenance personnel can send a remote reset command through the underground intrinsically safe monitoring system. After the reset, the main control unit automatically completes full parameter detection. After confirming that there are no abnormalities, the power supply is restored, reducing the difficulty and safety risks of underground on-site operation and maintenance.

[0042] This technical solution achieves real-time dynamic monitoring of intrinsic safety performance at the ia level by adding specialized detection for intrinsic safety anomalies. It can promptly detect anomalies in energy-limiting circuits and isolation modules, preventing excessive output energy due to intrinsic safety downgrades, thus further enhancing the intrinsic safety of the equipment and meeting the stringent requirements of the flammable and explosive environment in underground coal mines. By optimizing the automatic fault recovery mechanism, the frequency of manual intervention is reduced, especially the remote reset function, which lowers the difficulty and safety risks of on-site underground maintenance and improves maintenance efficiency. Simultaneously, the rigorous nature of multi-level automatic recovery (multiple parameter checks and delayed recovery) avoids equipment damage caused by repeated faults, further extending the lifespan of the power converter and reducing maintenance costs. It is suitable for scenarios where maintenance is inconvenient, such as deep underground locations.

[0043] The above description of the embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for detecting and protecting power converter malfunctions, characterized in that, An intrinsically safe power converter for use in flammable and explosive environments in underground coal mines. The converter transforms three IB-level intrinsically safe power inputs into three IA-level intrinsically safe power outputs. The anomaly detection and protection method includes the following steps: S1. Multi-parameter synchronous acquisition: Through the built-in sampling circuit and main control unit, the input voltage and current of each channel, the output voltage and current of each channel, and the operating temperature of the internal core module are collected in real time. At the same time, the working status of the soft start circuit, voltage and current limiting circuit, electrical isolation module and intrinsic safety level determination circuit are monitored simultaneously. S2. Threshold comparison and anomaly judgment: The collected electrical and temperature parameters are compared in real time with the intrinsically safe thresholds of level ia, the normal operating range thresholds, and the fault warning thresholds preset according to the GB / T3836 series standards. When the parameters exceed the limits, the energy limiting circuit is abnormal, the soft start fails to meet the standard, the temperature exceeds the upper limit, or the electrical isolation fails, the corresponding channel or the whole machine is judged to be in an abnormal state. S3. Graded protection execution: Graded protection is executed according to the type, severity and intrinsic safety impact level of the anomaly. The power supply continuity is maintained while ensuring that the output energy does not exceed the ia safety limit, so as to avoid the shutdown of the whole machine or the explosion of an explosive environment caused by a single fault. S4. Fault Handling and Recovery: Real-time latching, recording, and uploading of parameters for all abnormal states, enabling traceable, monitorable, and tiered recovery of faults.

2. The power converter anomaly detection and protection method according to claim 1, characterized in that, Abnormal conditions include at least one of the following: overvoltage, undervoltage, overcurrent, short circuit, overtemperature, soft start failure, intrinsic safety degradation, voltage limiting circuit failure, current limiting circuit failure, and electrical isolation abnormality.

3. The power converter anomaly detection and protection method according to claim 1, characterized in that, Real-time data collection includes: The voltage and current of the three input power supplies are collected independently. The voltage, current, and loop impedance of the three output ia-level power supplies are collected independently. Every 10ms to 100ms, a round of full parameter acquisition, threshold comparison, and anomaly detection is completed.

4. The power converter anomaly detection and protection method according to claim 1, characterized in that, Graded protection actions include: Level 1 protection: Performs dynamic current limiting, real-time voltage limiting, and reduces PWM duty cycle to correct abnormal parameters without interrupting output; Level 2 protection: shuts down the corresponding single output that malfunctions, while maintaining normal power supply to the other outputs; Level 3 protection: Immediately disconnects the entire input power supply, latches the fault status, and prohibits automatic restart.

5. The power converter anomaly detection and protection method according to claim 1, characterized in that, It also includes soft start detection and protection: after power-on, the voltage rise slope and surge current peak value during the soft start phase are detected in real time; if the slope is too fast or the peak value exceeds the threshold, the soft start abnormality is immediately determined and the output is cut off to prevent damage to the upstream power supply and downstream load.

6. The power converter anomaly detection and protection method according to claim 1, characterized in that, It also includes intrinsic safety level anomaly detection: real-time monitoring of the working status of the voltage limiting circuit, current limiting circuit, and isolation module; when the energy limiting circuit fails and cannot guarantee the ia level safe energy output, the intrinsic safety ia level is determined to be failed, and three-level protection is executed.

7. The power converter anomaly detection and protection method according to claim 1, characterized in that, It also includes fault recording and uploading: latching the fault type, occurrence time, fault parameter value, and fault channel; and uploading the fault information to the host computer or the underground intrinsically safe monitoring system via serial port, RS485, or intrinsically safe bus.

8. The power converter anomaly detection and protection method according to claim 1, characterized in that, It also includes automatic fault recovery: after the third-level protection latch is locked, it only supports manual reset to release; after the abnormal cause of the first / second-level protection is eliminated, it automatically restores normal output.

9. The power converter anomaly detection and protection method according to claim 1, characterized in that, The preset thresholds, current limits, voltage limits, and energy limits are all set according to the GB / T3836.4 intrinsic safety standard to ensure that the output energy does not exceed the ia-level safety limit under any operating condition.

10. The power converter anomaly detection and protection method according to claim 1, characterized in that, The anomaly detection and protection method is specifically designed for intrinsically safe three-input three-output power converters used in mining applications that convert IB-level inputs to IA-level outputs.

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