Method for improving reliability of controller of converter

Abstract

The invention belongs to the technical field of special circuit rectification, and relates to a method for improving the reliability of a controller of a converter. The method comprises the following steps: detecting the voltage in a control cabinet; when the voltage in the cabinet is lower than a safe voltage threshold value, identifying a first port through a terminal row diagram and a port physical identifier of the control cabinet; otherwise, alarming; the first port is a voltage sampling port; replacing the terminal connected with the first port with a first terminal through a key slot guide structure of the terminal and the port; determining a second part through the internal structure of the control cabinet and the physical identifier of the part, and carrying out insulation processing on the second part; the second component is a control box comprising a voltage sampling terminal in the converter controller; through accurate terminal matching, multi-dimensional insulation processing and multiple over-current protection, the reliability of the controller is significantly improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of circuit rectification, and discloses a method for improving the reliability of a controller of a converter. BACKGROUND

[0002] The core reason for the controller voltage sampling interface burnout fault of a three-level converter is that the electrical spacing and the creepage distance of a voltage sampling terminal (such as a P0B1 / P0B2 port) are insufficient, so that electric breakdown or creepage occurs under a high-voltage environment. The traditional rectification method only simply replaces the terminal or locally insulates, and has the following problems: the terminal selection lacks a mistaken insertion prevention design; different ports (such as 2x6P and 2x7P) are not matched with differentiated terminals, and manual checking is easy to mix insertion; insulation protection is not comprehensive; only partial areas are glued, a three-dimensional protection is not formed, and the risk of cable head lapping sheet metal is not completely eliminated; overcurrent protection is missing; the voltage sampling circuit is not provided with an independent fuse, and the fault current cannot be quickly cut off when overcurrent occurs, so that the terminal is overheated and burned out.

[0003] In view of the above problems, the application provides a method for improving the reliability of a controller of a converter, which significantly improves the reliability of the controller through accurate terminal matching, multi-dimensional insulation treatment and multiple overcurrent protection. SUMMARY

[0004] The application aims to provide a method for improving the reliability of a controller of a converter, and the specific scheme is as follows:

[0005] The cabinet voltage of a control cabinet is detected; when the cabinet voltage is lower than a safety voltage threshold, a first port is identified through a terminal arrangement diagram and a port physical mark of the control cabinet; otherwise, an alarm is given; the first port is a voltage sampling port; a terminal connected with the first port is replaced with a first terminal through a key groove guide structure of the terminal and the port; a second component is determined through an internal structure and a component physical mark of the control cabinet, and the second component is insulated; the second component is a control box containing a voltage sampling terminal in a converter controller.

[0006] Further, the first port includes a DC bus voltage sampling port, a stator voltage sampling port and a main fuse rear end voltage sampling port; the DC bus voltage sampling port includes P0B1 and P0B2 ports; the stator voltage sampling port includes a P0E1 port; and the main fuse rear end voltage sampling port includes P0C and P0D ports.

[0007] Further, the first terminal includes an FD26140220 terminal and an FD26140221 terminal; and the replacing the terminal connected with the first port with the first terminal includes: replacing the terminal connected with the P0B1 and P0B2 ports of the DC bus voltage sampling port with the FD26140220 terminal; and replacing the terminal connected with the P0E1 port of the stator voltage sampling port and the P0C and P0D ports of the main fuse rear-end voltage sampling port with the FD26140221 terminal.

[0008] Further, the insulation treatment on the second component includes: identifying a control box bottom, and adding an insulation film on the control box bottom; identifying a first exposed area, a second exposed area, a third exposed area, a fourth exposed area and a fifth exposed area of the control box through terminal arrangement and port physical identification of the second component; the first exposed area is a pin exposed area of a single board in the control box; the second exposed area is a pin exposed area of a high-voltage terminal in the control box; the third exposed area is a hole arrangement area of the high-voltage terminal; the fourth exposed area is a port connection area of the high-voltage terminal; and insulating glue is coated on the first exposed area, the second exposed area, the third exposed area and the fourth exposed area.

[0009] Further, the method further includes setting a protection fuse in the voltage sampling loop; and the protection fuse is set by setting a voltage sampling fuse.

[0010] Further, the voltage sampling loop includes a DC bus voltage sampling loop, a stator voltage sampling loop and a main fuse rear-end voltage sampling loop; and the setting the protection fuse in the voltage sampling loop includes: connecting voltage detection lines P0B1:1, P0B1:7, P0B1:11 and P0B2:7 of the DC bus voltage sampling loop to the protection fuse; connecting voltage detection lines P0E1:1, P0E1:7 and P0E1:13 of the stator voltage sampling loop to the protection fuse; and connecting voltage detection lines of the main fuse rear-end voltage sampling loop to the protection fuse.

[0011] Further, the method further includes powering off the control cabinet, including: judging whether a first tripping signal of a grid-side circuit breaker of a converter is received; when the first tripping signal is received, judging whether a second tripping signal of a low-voltage side circuit breaker of a transformer is received; if the first tripping signal is not received, issuing a first tripping instruction to disconnect the grid-side circuit breaker; when the second tripping signal is received, judging whether a third tripping signal of a control power of the converter is received; if the second tripping signal is not received, issuing a second tripping instruction to disconnect the low-voltage side circuit breaker of the transformer; when the third tripping signal is received, issuing a rectification instruction; and if the third tripping signal is not received, issuing a third tripping instruction to disconnect the control power of the converter.

[0012] Further, the method further comprises disassembling the second component at a preset disassembly torque, including: collecting a measured disassembly torque; calculating a disassembly torque difference between the measured disassembly torque and the preset disassembly torque; and when the disassembly torque difference is less than 0, increasing the disassembly torque by a preset disassembly torque step to a disassembly torque difference greater than or equal to 0.

[0013] Further, the method further comprises assembling the second component at a preset assembly torque, including: collecting a measured assembly torque; calculating an assembly torque difference between the measured assembly torque and the preset assembly torque; when the assembly torque difference is less than a first proportion of the preset assembly torque, increasing the assembly torque by a preset assembly torque step to a difference greater than or equal to 0; and when the assembly torque difference is greater than a second proportion of the preset assembly torque, retightening to a target torque value after backtracking a preset number of turns.

[0014] Further, the preset disassembly torque is 5 kgf.cm; the preset disassembly torque step is 1 kgf.cm / time; the preset assembly torque is 12 kgf.cm; the first proportion is -10%; the second proportion is 10%; the preset assembly torque step is 0.2-1 kgf.cm / time; and the preset number of turns is 1 / 4 turn.

[0015] Advantages of the present application:

[0016] The electrical safety is improved, the terminal spacing is increased by 30%, the insulation film and high-voltage glue are matched, the creepage distance is increased from 15 mm to 22 mm, and the GB / T 16935.1-2020 standard is met.

[0017] The fault protection is enhanced, the nine-channel independent fuse realizes 100% overcurrent protection, the response time is <50 μs, and the response time is improved by 4 compared with the traditional scheme.

[0018] The standardization operation process is realized, the terminal model is uniquely matched with the port, the torque is accurately controlled, human errors are avoided, and the rectification efficiency is improved by 40%. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 An example flowchart of a method for improving the reliability of a controller of a converter is provided for some embodiments of the present application. DETAILED DESCRIPTION

[0020] To make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, rather than all embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0021] Figure 1An exemplary flowchart of a method for improving the reliability of a controller of a converter is provided for some embodiments of the present application. As shown in Figure 1 the controller modification includes the following steps:

[0022] At step 110, the voltage inside the control cabinet is detected. The control cabinet is an electrical equipment that assembles the switching devices, measuring instruments, protective appliances, control elements and auxiliary devices of the control converter in a closed or semi-closed metal cabinet or on a screen according to the electrical wiring requirements. The voltage inside the cabinet refers to the potential difference between the conductive parts inside the control cabinet circuit, electrical elements, busbar, terminal block, etc., or between the conductive parts and the ground. In the context of converter controller modification, after the converter grid-side circuit breaker is turned off and the capacitor is discharged, a high-precision digital multimeter is used to measure the exposed conductive parts such as busbar and terminal block inside the control cabinet. At this time, the potential difference between the DC busbar and the cabinet body is the voltage inside the cabinet. By detecting whether the voltage is lower than the safety threshold, it can be determined whether the control cabinet can be safely operated subsequently.

[0023] At step 120, when the voltage inside the cabinet is lower than the safety voltage threshold, a first port is identified through the terminal block diagram and port physical identification of the control cabinet; otherwise, an alarm is given. The first port is a voltage sampling port. The safety voltage threshold refers to the voltage limit value that ensures no electric shock risk when touched. For example, AC voltage ≤ 36V and DC voltage ≤ 60V, etc. If the voltage inside the cabinet is higher than the threshold, there is a risk of electric shock. The terminal block diagram refers to a drawing that details the layout, port number, function definition and wiring relationship of the terminal block inside the control cabinet. For example, the drawing will indicate that P0B1 / P0B2 is a 2×6P structure DC bus voltage sampling port and P0C / P0D / P0E1 is a 2×7P structure other voltage sampling port. The port physical identification refers to the identification that indicates the identity, function or number of the port. The first port includes a DC bus voltage sampling port, a stator voltage sampling port and a main fuse back-end voltage sampling port. The DC bus voltage sampling port is a port for collecting the DC bus voltage signal in the converter. Through this port, the voltage value of the DC bus can be obtained, providing voltage data for converter control, monitoring and protection functions. The DC bus voltage sampling port includes P0B1 and P0B2 ports. The stator voltage sampling port is a port for sampling the motor stator voltage, which can monitor the voltage of the stator winding in real time, ensure that the motor operates within the normal voltage range and ensure stable operation of the motor. The stator voltage sampling port includes P0E1 port. The main fuse back-end voltage sampling port is a port for collecting the voltage of the main fuse back-end circuit, which can monitor the voltage state of the main fuse back-end electrical components and detect abnormal voltage in time to ensure the safety of the circuit. The main fuse back-end voltage sampling port includes P0C and P0D ports.

[0024] Step 130, replace the terminal connected with the first port with the first terminal through the keyway guide structure of the terminal and the port. The keyway guide structure refers to the structure for mechanical positioning and cooperation of the terminal and the port. For example, a protrusion and a groove that match each other can be respectively provided on the terminal and the port, and the accurate butt joint of the two guides the terminal to be accurately inserted into the port, prevents misinsertion, and ensures the uniqueness and accuracy of the connection. The first terminal refers to a special terminal matched with the voltage sampling port, which has a specific pin layout and mechanical structure to realize the voltage sampling function. For example, the FD26140220 terminal (2x6P structure) for the DC bus voltage sampling port (P0B1, P0B2), and the FD26140221 terminal (2x7P structure) for other first ports (such as P0C, P0D, P0E1). It is identified that the DC bus voltage sampling port (such as the P0B1 port, the first port) has a horizontal groove structure as the port keyway. In some embodiments, the robot gripper can automatically replace the terminal grabbing tool, grab the first terminal (such as the FD26140220 terminal, which has a protrusion structure matching the port keyway on the side) matched with the port from the material rack. Under the visual guidance, the robot controls the mechanical arm to move accurately, aligns the protrusion keyway of the terminal with the groove keyway of the port, and guides the terminal to be accurately inserted into the port through the accurate cooperation of the keyway guide structure, thereby completing the automatic replacement of the first terminal. In this process, the keyway guide structure ensures that the terminal and the port are uniquely and correctly matched. Specifically, the terminals connected with the P0B1 and P0B2 ports of the DC bus voltage sampling port are replaced with the FD26140220 terminal; the terminal connected with the P0E1 port of the stator voltage sampling port and the P0C and P0D ports of the main fuse rear voltage sampling port is replaced with the FD26140221 terminal.

[0025] Step 140, determine the second component through the internal structure and component physical identification of the control cabinet, and perform insulation treatment on the second component; the second component refers to the control box containing the voltage sampling terminal in the converter controller. The internal structure refers to the physical characteristics of the layout, structure, shape, installation position and mutual relationship of the internal components of the control cabinet. The component physical identification is used to indicate the identification, function, name, number or characteristics of the component. Through image recognition algorithm, the modules in the cabinet are matched with the pre-stored internal structure model of the control box, and the identification is recognized, and the module that meets the internal structure characteristics of the control box and has a clear component physical identification is taken as the second component.

[0026] In some embodiments, the second component is insulated, including: identifying the bottom of the control box and adding an insulating film to the bottom of the control box. Scanning the inside of the control cabinet to construct a spatial model of the control box. Identify the geometric features and physical markers of the control box. Compare the real-time scanning data with the pre-stored three-dimensional model of the control box, combined with the OCR recognition result of the bottom label, to accurately determine the spatial position and pose of the control box bottom. Replace the flexible gripper suitable for narrow space to grab the pre-cut insulating film from the feed tray. Based on the three-dimensional model of the control box bottom, the mechanical arm path is planned through inverse kinematics algorithm to make the edge of the insulating film accurately aligned with the bottom contour. During the application process, the miniature roller at the end of the gripper synchronously applies 0.5N pressure to ensure that the film material is completely attached to the bottom surface, while eliminating air bubbles. For control boxes that require edge folding treatment on the bottom edge (for example, square structure), a 90° folding operation is performed by visual guidance control gripper to wrap the edge of the insulating film to the side of the bottom, and the built-in blade completes the precise cutting of the excess film material. Through the terminal layout and port physical markers of the second component, the first exposed area, the second exposed area, the third exposed area and the fourth exposed area of the control box are identified; the first exposed area is the pin exposed area of the single board inside the control box; the second exposed area is the pin exposed area of the high-voltage terminal inside the control box; the third exposed area is the hole area of the high-voltage terminal; the fourth exposed area is the port connection of the high-voltage terminal. Apply insulating glue to the first exposed area, the second exposed area, the third exposed area and the fourth exposed area. Obtain the control box top single board image, segment the control box top single board image by image segmentation algorithm, and identify the exposed metal pins with regular arrangement. Match the exposed metal pins with regular arrangement with the control box electronic terminal layout to determine the first exposed area. For example, identify the area with regular arrangement of metal pins with a pitch of 3.5mm and a length of 5mm as the first exposed area, and match the first exposed area to the control box electronic terminal layout. Use a 1mm diameter straight nozzle dispensing head to align the pin base of the first exposed area, move along the pin axis at a speed of 10mm / s, with a glue layer thickness of 1.2-1.5mm, and a pin base glue layer covering length ≥3mm to form an umbrella-shaped anti-creeper structure. After gluing, stand for 45 minutes (ensure the environment temperature is 25℃±2℃ through temperature and humidity sensor), and visually review the glue layer for air bubbles and exposed pins. Obtain the port image and identify the port physical markers on the port image to obtain the second exposed area; match the second exposed area with the terminal layout to determine the second exposed area.For example, the terminal marked as "HV" on the port image and not covered by insulation is identified as a pending second exposed area. The pending second exposed area is matched with the location of the high-voltage terminal POC / POD / POE1, etc. in the terminal array diagram, and the matching is passed as a second exposed area. Turn the control box upside down with the bottom facing up, use a 45° curved nozzle dispensing head to dispense glue into the single board gap, and perform circular dispensing at the root of each exposed pin. The glue covers 100% of the exposed part of the pin, with a thickness of 1.0-1.2mm, avoiding the connection point at the top of the pin to ensure that the electrical connection is not affected. Through image acquisition and processing, identify the array holes on multiple terminals in the diagram (for example, six terminals), the characteristics of the array holes are: 2.5mm diameter circular holes, 4mm spacing, arranged in 2x7P. Determine the array hole depth and front and back positions by light scanning. For the front position of the array hole: the dispensing head dispenses glue circularly along the edge of the array hole, and the glue penetrates into the hole with a depth of ≥2mm (the glue path resistance is monitored by a pressure sensor); for the back position of the array hole: use a 45° curved nozzle to extend into the bottom of the array hole, and dispense glue in a blind hole filling manner to form a sealing layer with a thickness of 0.8mm±0.1mm. After dispensing glue on the back, let it stand for 50 minutes, and detect the degree of glue solidification by an infrared sensor. Determine the connection position of P0B1 / P0B2, etc. ports and external cables by image acquisition and recognition method, and detect the exposed part of the metal connection (for example, the edge area of the terminal in contact with the port). Use circular dispensing process on the front of the port connection, and the glue layer covers the connection gap (width 2mm) to prevent moisture from entering; reinforce the dispensing on the back connection point, and the glue layer has a thickness of 1.0mm to ensure that the insulation level of the connection is ≥100MΩ. Verify that the insulation resistance of the port connection after dispensing glue is improved by more than 10 times compared to before dispensing glue by scanning with an insulation resistance meter.

[0027] In some embodiments, a protection fuse is further included in the voltage sampling circuit; the protection fuse is implemented by setting a voltage sampling fuse. The protection fuse refers to an electrical element installed in the voltage sampling circuit, which is used to quickly cut off the circuit under abnormal working conditions such as overcurrent, overvoltage, etc., to protect the voltage sampling system of the converter controller from overload damage. In some embodiments, the model of the protection fuse is FD27150144 (parameters: 1500VDC-5A-30kA-gPV), which is suitable for the high-voltage DC and AC sampling circuit of the 1140V (10.5kV) three-level system of the converter. The voltage sampling circuit includes a DC bus voltage sampling circuit, a stator voltage sampling circuit, and a main fuse rear-end voltage sampling circuit; the protection fuse is set in the voltage sampling circuit, including: connecting the voltage detection lines P0B1:1, P0B1:7, P0B1:11, and P0B2:7 of the DC bus voltage sampling circuit to the protection fuse; connecting the voltage detection lines P0E1:1, P0E1:7, and P0E1:13 of the stator voltage sampling circuit to the protection fuse; and connecting the voltage detection lines of the main fuse rear-end voltage sampling circuit to the protection fuse.

[0028] In some embodiments, the control cabinet is also powered off, including: determining whether a first tripping signal of the grid-side circuit breaker of the converter is received; the first tripping signal is an electrical signal representing the tripping state of the grid-side circuit breaker. After receiving the first tripping signal, it is determined whether a second tripping signal of the low-voltage side circuit breaker of the transformer is received; if the first tripping signal is not received, a first tripping instruction is sent to open the grid-side circuit breaker; the second tripping signal is an electrical signal representing the tripping state of the low-voltage side circuit breaker of the transformer. After receiving the second tripping signal, it is determined whether a third tripping signal of the converter control power is received; if the second tripping signal is not received, a second tripping instruction is sent to open the low-voltage side circuit breaker of the transformer; after receiving the third tripping signal, a rectification instruction is sent; if the third tripping signal is not received, a third tripping instruction is sent to open the converter control power. The third tripping signal is an electrical signal representing the tripping state of the converter control power (such as UPS power supply, control loop power supply). Specifically, the PLC reads the grid-side circuit breaker state in the converter monitoring system through the Modbus TCP protocol, and refreshes every 200 ms. If no tripping signal is received within 10 seconds (state = 1), the first tripping instruction is triggered: the PLC outputs 24Vdc to the grid-side circuit breaker tripping coil, and simultaneously presses the circuit breaker manual tripping button (backup redundant operation). After tripping, the busbar voltage is detected by the auxiliary contact signal (state = 0) and the voltage sensor (should be <10Vdc), and the grid-side circuit breaker is double confirmed to be disconnected. Then, after confirming that the grid-side circuit breaker has been disconnected (first tripping signal = 0), the PLC reads the low-voltage side circuit breaker state of the transformer. If no tripping signal is received within 30 seconds (state = 1), the PLC sends a Modbus RTU instruction (slave address 0x01) to the low-voltage side circuit breaker controller to force tripping; if it still does not respond after 15 seconds, the hardwired tripping is triggered. The circuit breaker operating mechanism position is photographed to confirm that the mechanical contacts are separated (stroke ≥ 10 mm) to avoid misjudgment caused by signal transmission failure. Finally, after confirming that the low-voltage side circuit breaker has been disconnected (second tripping signal = 0), the voltage sensor detects the converter control power (UPS output end): if the voltage > 60Vdc (not disconnected), the PLC controls the contactor coil to lose power, cutting off the UPS input power, and the robot disconnects the control power air switch. If the voltage < 60Vdc (already disconnected), enter the "rectification ready" state. Scan all exposed conductive parts (busbar, terminal block, etc.) in the cabinet through the multi-channel voltage sensor, and confirm that the voltage of all detection points is <36Vac / 60Vdc.

[0029] 36Vac / 60Vdc, the "allow rectification" green light (24Vdc power supply, brightness ≥ 200mcd) on the control cabinet panel is lit.

[0030] In some embodiments, the second component is assembled with a preset assembly torque, including: collecting a measured assembly torque; calculating an assembly torque difference between the measured assembly torque and the preset assembly torque; when the assembly torque difference is less than a first proportion of the preset assembly torque, increasing the assembly torque by a preset assembly torque step to a difference greater than or equal to 0; and when the assembly torque difference is greater than a second proportion of the preset assembly torque, retightening after backspacing the preset turns to a target torque value. The preset disassembly torque refers to a standard torque value preset for disassembling the control box. For example, the preset disassembly torque can be 5 kgf.cm. The measured disassembly torque refers to the disassembly torque value collected in real time by the torque measuring tool. For example, when disassembling the control box screw using a high-precision torque wrench, the torque reading displayed in real time on the tool display screen. The disassembly torque difference refers to the numerical difference between the measured disassembly torque and the preset disassembly torque. If the difference is less than 0, it indicates that the measured torque is less than the preset value, and the torque needs to be increased. If it is greater than or equal to 0, it indicates that the current torque meets or exceeds the preset requirement, and when it exceeds the preset torque requirement, the current disassembly torque can be appropriately reduced. The preset disassembly torque step refers to the fixed amplitude of each adjustment of the disassembly torque, which is used to gradually adjust the disassembly torque when the disassembly torque difference is less than 0. For example, the preset disassembly torque step can be 1 kgf.cm / time, i.e., the current torque is increased by 1 kgf.cm each time until the disassembly requirement is met. Specifically, the control box is fixed by 6 M4 combination screws, and the preset disassembly torque is set to 5 kgf.cm. A torque wrench with a force sensor is used to start disassembling one of the screws, and the measured disassembly torque is collected in real time. The first measurement is 4 kgf.cm. The disassembly torque difference is -1 kgf.cm, which is less than 0. The disassembly torque is increased by the preset disassembly torque step of 1 kgf.cm / time, and the torque wrench is adjusted to 5 kgf.cm for disassembly again. At this time, the measured disassembly torque reaches, successfully disassembling the screw, and avoiding the problems of being unable to disassemble due to too small torque or damaging the thread due to too large torque. The above steps are repeated to complete the disassembly of the remaining 5 screws, ensuring that the control box is safely and completely disassembled, providing conditions for subsequent insulation processing, terminal replacement, etc.

[0031] In some embodiments, further comprising assembling the second component with a preset assembly torque, comprising: collecting a measured assembly torque; calculating an assembly torque difference between the measured assembly torque and the preset assembly torque; increasing the assembly torque by a preset assembly torque step when the assembly torque difference is less than a first proportion of the preset assembly torque to a difference greater than or equal to 0; and back off a preset circle and tighten again to a target torque value when the assembly torque difference is greater than a second proportion of the preset assembly torque. The preset assembly torque refers to a standard torque value preset for assembly operation. For example, to ensure that the upper and lower covers of the control box are tightly combined without damaging the threads, the preset assembly torque is set to 12 kgf·cm for the 8 M4 nuts at the bottom and the 6 M4 screws on the side. The measured assembly torque refers to the assembly torque value collected in real time during actual assembly by a torque measurement tool. For example, when tightening the control box screws using an electric torque screwdriver, the real-time torque reading feedback by the tool. The assembly torque difference refers to the numerical difference between the measured assembly torque and the preset assembly torque. The first proportion of the preset assembly torque refers to a proportion threshold of the preset assembly torque, which is used to determine whether the measured torque is significantly less than the preset value. For example, the first proportion is set to -10%. The preset assembly torque step refers to a fixed amplitude preset for each increase in assembly torque. For example, the preset assembly torque step is set to 0.2-1 kgf·cm per time. The second proportion of the preset assembly torque refers to another proportion threshold of the preset assembly torque, which is used to determine whether the measured torque is significantly greater than the preset value. For example, the second proportion is set to 10%. The preset circle refers to a predetermined number of back-off circles, which is used to adjust when the torque is too large. For example, the preset back-off circle number is set to 1 / 4 circle. Specifically, the control box is fixed by 8 M4 nuts at the bottom and 6 M4 screws on the side, and the preset assembly torque is set to 12 kgf·cm. Using an electric torque screwdriver to start assembling one of the bottom M4 nuts, the measured assembly torque is collected in real time, and the first measurement is 10 kgf·cm. The assembly torque difference is calculated to be -2 kgf·cm, which is less than the first proportion of the preset assembly torque 10.8 kgf·cm. The assembly torque is increased by the preset assembly torque step of 0.5 kgf·cm, and the torque screwdriver is adjusted to 10.5 kgf·cm, and tightened again. If it is still insufficient, continue to increase by a step of 0.5 kgf·cm until the measured torque reaches 12 kgf·cm. If the measured torque reaches 14 kgf·cm when assembling another screw, the difference is calculated to be 2 kgf·cm, which is greater than the second proportion of the preset assembly torque 13.2 kgf·cm. At this time, the screw is backed off by 1 / 4 circle and then tightened again at a torque of 12 kgf·cm to ensure that the target torque value is reached. Repeat the above steps to complete the assembly of all nuts and screws to ensure that the control box is tightly sealed and the threads are not damaged. The above is only a preferred embodiment of the present application and is not intended to limit the present application. Those skilled in the art can make various changes and modifications to the present application.Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of improving the reliability of a controller of a power converter, characterized by, The method comprises the following steps: detecting the voltage in the control cabinet; when the voltage in the cabinet is lower than the safety voltage threshold, identifying a first port through the terminal array diagram and port physical identification of the control cabinet; otherwise, alarming; the first port is a voltage sampling port; replacing the terminal connected with the first port with a first terminal through the key groove guide structure of the terminal and the port; determining a second component through the internal structure and component physical identification of the control cabinet, and insulating the second component; the second component is a control box containing a voltage sampling terminal in the converter controller.

2. The method of improving the reliability of a controller of a power converter of claim 1, wherein, The first port comprises a DC bus voltage sampling port, a stator voltage sampling port and a main fuse rear end voltage sampling port; The DC bus voltage sampling port comprises P0B1 and P0B2 ports; The stator voltage sampling port comprises P0E1 port; The main fuse rear end voltage sampling port comprises P0C and P0D ports.

3. The method of improving the reliability of a controller of a power converter of claim 2, wherein, The first terminal comprises FD26140220 terminal and FD26140221 terminal; the replacement of the terminal connected with the first port with the first terminal comprises: replacing the terminal connected with the P0B1 and P0B2 ports of the DC bus voltage sampling port with the FD26140220 terminal; replacing the terminal connected with the P0E1 port of the stator voltage sampling port and the P0C and P0D ports of the main fuse rear end voltage sampling port with the FD26140221 terminal.

4. The method of improving the reliability of a controller of a power converter of claim 1, wherein, The insulation treatment of the second component comprises: identifying the bottom of the control box and adding an insulating film to the bottom of the control box; identifying the first exposed area, the second exposed area, the third exposed area and the fourth exposed area of the control box through the terminal array diagram and port physical identification of the second component; the first exposed area is the pin exposed area of the single board in the control box; the second exposed area is the pin exposed area of the high-voltage terminal in the control box; the third exposed area is the array hole area of the high-voltage terminal; the fourth exposed area is the port connection of the high-voltage terminal; coating insulating glue on the first exposed area, the second exposed area, the third exposed area and the fourth exposed area.

5. The method of improving the reliability of a controller of a power converter of claim 1, wherein, Further comprising setting a protection fuse in the voltage sampling circuit; the protection fuse is realized by setting a voltage sampling fuse.

6. The method of improving the reliability of a controller of a power converter of claim 5, wherein, The voltage sampling circuit comprises a DC bus voltage sampling circuit, a stator voltage sampling circuit and a main fuse rear end voltage sampling circuit; The setting of the protection fuse in the voltage sampling circuit comprises: connecting the voltage detection lines P0B1:1, P0B1:7, P0B1:11 and P0B2:7 of the DC bus voltage sampling circuit to the protection fuse; connecting the voltage detection lines P0E1:1, P0E1:7 and P0E1:13 of the stator voltage sampling circuit to the protection fuse; connecting the voltage detection lines of the main fuse rear end voltage sampling circuit to the protection fuse.

7. The method of improving the reliability of a controller of a power converter of claim 1, wherein, Further comprising powering off the control cabinet, comprising: determining whether a first opening signal of the converter grid side circuit breaker is received; When the first tripping signal is received, it is judged whether the second tripping signal of the low-voltage side circuit breaker of the box transformer is received; if the first tripping signal is not received, the first tripping instruction is sent to disconnect the net side circuit breaker; When the second tripping signal is received, it is judged whether the third tripping signal of the converter control power is received; if the second tripping signal is not received, the second tripping instruction is sent to disconnect the low-voltage side circuit breaker of the box transformer; When the third tripping signal is received, the rectification instruction is sent; if the third tripping signal is not received, the third tripping instruction is sent to disconnect the converter control power.

8. The method of improving the reliability of a controller of a power converter of claim 1, wherein, Also including disassembling the second component with a preset disassembly torque, comprising: Collecting the measured disassembly torque; Calculating the disassembly torque difference between the measured disassembly torque and the preset disassembly torque; When the disassembly torque difference is less than 0, increase the disassembly torque to the disassembly torque difference greater than or equal to 0 by a preset disassembly torque step.

9. The method of improving the reliability of a controller of a power converter of claim 8, wherein, Also including assembling the second component with a preset assembly torque, comprising: Collecting the measured assembly torque; Calculating the assembly torque difference between the measured assembly torque and the preset assembly torque; When the assembly torque difference is less than the first proportion of the preset assembly torque, increase the assembly torque to the difference greater than or equal to 0 by a preset assembly torque step; When the assembly torque difference is greater than the second proportion of the preset assembly torque, back off the preset circle and tighten to the target torque value again.

10. The method of improving the reliability of a controller of a power converter of claim 9, wherein, The preset disassembly torque is 5kgf.cm; the preset disassembly torque step is 1kgf·cm / time; the preset assembly torque is 12kgf.cm; the first proportion is-10%; the second proportion is 10%; the preset assembly torque step is 0.2-1kgf·cm / time; the preset circle is 1 / 4 circle.

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