Winding device for primary coil of current transformer and winding method thereof

Abstract

The application relates to a winding device for a primary coil of a current transformer and a winding method thereof, and belongs to the technical field of current transformers. The device comprises a flattening mechanism, the flattening mechanism comprises an adaptive floating pressure head module, a constant pressure driving and sensing module and a control unit. The method comprises setting a target pressure value according to the specification of silk tape; starting winding, controlling the contact of the compression roller with the silk tape and reaching an initial pressure, and entering a constant pressure control mode; in the process of winding rotation of the winding module, the feedback value of the pressure sensor is monitored in real time, the linear driver is dynamically adjusted through closed-loop control, the actual pressure of the compression roller on the silk tape is maintained near the target pressure value, the motion path of the compression roller is matched with the winding track, the accurate closed-loop control of pressure is realized through the "pressure sensor + servo driver + intelligent algorithm", and the technical problem of fitting a complex winding curved surface is solved through the "gimbal connection structure + elastic compression roller".

Description

Technical Field

[0001] This invention relates to a winding device and method for the primary coil of a current transformer, belonging to the field of current transformer technology. Background Technology

[0002] In the manufacturing process of current transformers, insulating wire wrapping is wound onto a microcrystalline iron core to form a primary coil. Current technology typically uses a right-angle bracket and pressure rollers to periodically flatten the wire wrapping during winding to improve the coil's compactness and flatness.

[0003] However, when implementing the existing technology, the following technical bottlenecks were found:

[0004] Insufficient pressure consistency and adaptability: Existing devices use pneumatic cylinders to drive a right-angle seat for overall pressing, resulting in a fixed pressure that cannot be dynamically adjusted based on changes in the thickness, hardness, or number of layers of the silk-covered tape. For silk-covered tapes of different materials or specifications, excessive pressure may damage the insulation layer, while insufficient pressure cannot eliminate wrinkles, affecting the winding quality.

[0005] The flattening process has "blind spots" and interference: the device performs flattening once after rotating 90° at each corner of the rectangular base, with the pressure roller moving in a straight line. This method may result in the pressure roller not fully adhering to the surface of the silk wrapping tape near the edge of the rectangular base or in the sloping area where the coil has already been wound, leading to poor flattening in localized areas. Simultaneously, the vertical section of the right-angle base, acting as a rigid reference surface, may interfere with the raised sidewalls of the coil during multi-layer winding, affecting winding continuity or causing coil deformation.

[0006] Lack of real-time monitoring and feedback: The flattening process is controlled in an open-loop manner, making it impossible to perceive the actual contact pressure between the pressure roller and the yarn wrapping tape or the flatness of the yarn wrapping tape surface in real time. When loose winding, interlayer misalignment, or foreign objects occur, the device cannot automatically identify and adjust them, relying on manual intervention, which affects the level of production automation and product consistency.

[0007] For example, Chinese Patent Publication No. CN119132826A discloses a winding device and method for the primary coil of a current transformer, which suffers from the aforementioned bottlenecks. Therefore, there is an urgent need to develop a winding device and method that can achieve constant voltage self-compensation, adaptive winding surface, and real-time monitoring capabilities to overcome the aforementioned deficiencies of the prior art. Summary of the Invention

[0008] The purpose of this invention is to provide a winding device and method for the primary coil of a current transformer, which overcomes the shortcomings of existing winding devices in terms of pressure control, adaptability and intelligence, and can achieve constant pressure self-compensation, adaptive winding surface and real-time monitoring function.

[0009] The present invention discloses a winding device for the primary coil of a current transformer, comprising a base, a support, a winding module mounted on the support, a core base, and a wire wrapping conveying mechanism, and further comprising a flattening mechanism, wherein the flattening mechanism includes an adaptive floating pressure head module, a constant pressure drive and sensing module, and a control unit.

[0010] An adaptive floating pressure head module includes a pressure head mounting plate that can float along a direction perpendicular to the working surface of the winding module, and at least one pressure roller mounted on the pressure head mounting plate via a universal connection structure.

[0011] The constant pressure drive and sensing module includes a linear driver for driving the movement of the pressure head mounting plate, and a pressure sensor for detecting in real time the pressure applied by the pressure head to the tape.

[0012] The control unit is communicatively connected to the linear actuator, the pressure sensor, and the main drive motor that drives the winding module to rotate. Based on the feedback signal from the pressure sensor, the control unit adjusts the linear actuator through closed-loop control to maintain a constant pressure of the pressure head on the yarn wrapping; and controls the movement trajectory of the pressure head based on the rotation angle of the winding module.

[0013] By using pressure sensors for real-time detection and control unit closed-loop adjustment, the clamping force on the tape remains constant throughout the winding process, avoiding the problems of large pressure fluctuations and poor consistency in traditional manual or open-loop control. The pressure roller is connected to the pressure head mounting plate via a universal joint structure, allowing it to adaptively conform to the plane and corner slopes of the rectangular seat during winding, especially solving the technical problem of incomplete pressing and wrinkling in corner areas by traditional rigid pressure heads. The control unit synchronously controls the movement trajectory of the pressure head according to the rotation angle of the winding module, achieving precise synchronization between the flattening action and the winding process, improving the real-time performance and accuracy of flattening. The combination of constant pressure and adaptive bonding ensures that each layer of tape is wound tightly, flat, and wrinkle-free, significantly improving the insulation performance, mechanical strength, and appearance quality of the primary coil. The integration of force control closed-loop, mechanical adaptation, and motion synchronization control forms a complete intelligent flattening system. This solves the industry pain points of traditional winding devices, such as reliance on manual experience during flattening, inability to adapt to surface changes, and uncontrollable pressure.

[0014] Specifically, an embedded micro-film pressure sensor is directly integrated at the upper end of the universal joint structure or within the pressure roller bearing housing. The sensor's measuring surface is directly coupled to the force transmission path of the pressure roller, ensuring that the real-time detection is of the actual contact pressure of the pressure roller on the yarn wrapping, rather than the internal force of the mechanism. Preferably, the pressure head mounting plate is mounted on a floating mounting frame, which can move parallel to the working surface of the winding module to achieve lateral following of the flattening path. One or more pressure rollers can be installed, such as three, four, or eight, to enhance the pressing effect. Each pressure roller can be independently configured with a sensor to monitor the pressure distribution.

[0015] The floating mounting bracket can move along the working surface, ensuring that the pressure roller is always aligned with the winding point, thus avoiding lateral dragging or twisting of the yarn due to positional deviation.

[0016] Preferably, the roller surface of the pressure roller is made of an elastic material, or an elastic buffer layer is provided inside the pressure roller.

[0017] The elastic material or built-in buffer layer on the surface of the pressure roller can absorb localized impacts, preventing hard contact damage to the insulation surface of the silk-wrapped tape. The elastic roller surface can better adapt to the minor unevenness of the silk-wrapped tape surface, especially in multi-layer winding, compensating for interlayer height differences and improving pressing uniformity. The buffer structure can reduce mechanical vibration and noise during the pressing process, improving the stability of equipment operation.

[0018] Preferably, the control unit is a PLC controller.

[0019] It may also include a vision detection unit, wherein the control unit analyzes the winding quality based on the winding area image acquired by the vision detection unit, and adjusts the target pressure value or generates control commands based on the analysis results.

[0020] By monitoring winding quality in real time through a visual inspection unit, the system gains the ability to "see" and "judge," upgrading from "force control" to "quality control." Based on visual analysis results, it automatically adjusts clamping force or other process parameters, achieving dynamic optimization and improving adaptability to different materials and working conditions. It can detect defects such as wrinkles, misalignments, and gaps in real time, making timely adjustments or issuing alarms to reduce defective products and improve the first-pass yield.

[0021] Preferably, the working sidewall of the winding module is covered with a flexible padding layer.

[0022] The flexible padding layer reduces rigid friction between the wire wrapping tape and the sidewalls of the rectangular base, preventing scratches on the insulation layer during winding. The flexible material can deform appropriately to accommodate minor irregular protrusions that may appear on the coil sidewalls during multi-layer winding, avoiding interference or compression deformation. Reduced frictional resistance facilitates smooth wire wrapping during the winding process.

[0023] The present invention provides a winding method for a winding device for the primary coil of a current transformer, comprising:

[0024] Set the target pressure value according to the specifications of the tape.

[0025] Start the winding process, control the pressure roller to contact the yarn wrapping tape and reach the initial pressure, and enter the constant pressure control mode;

[0026] During the winding process of the winding module, the feedback value of the pressure sensor is monitored in real time, and the linear driver is dynamically adjusted through closed-loop control to keep the actual pressure of the pressure roller on the yarn package near the target pressure value.

[0027] The motion path of the pressure roller is controlled to match the winding trajectory.

[0028] By streamlining core control logic processes such as constant voltage control and trajectory matching, a set of repeatable and verifiable standard winding process methods is formed. Through parameterized settings and solidified control procedures, reliance on operator experience is reduced, facilitating the reproduction of high-quality winding results on different equipment or production lines. From contact recognition to constant voltage maintenance, the entire process is automated, significantly improving production efficiency and consistency.

[0029] Preferably, it includes the following steps:

[0030] S1: Winding preparation and parameter setting: Install the rectangular base of the corresponding specification and clamp the iron core; according to the material, thickness and coil process requirements of the wire wrapping tape, set the winding speed, target pressure value and pressure adjustment threshold in the control unit;

[0031] S2: Initial winding and pressure calibration: Start winding, and fix the first end of the wrapped tape to the rectangular base; the winding module starts to rotate, and the constant pressure drive and sensing module drive the adaptive floating pressure head module to approach the wrapped tape; when the pressure sensor detects that the contact pressure has reached the preset initial value, the control unit records the current position as the flattening start reference point and enters the constant pressure control mode;

[0032] S3: Constant pressure adaptive winding: The winding module rotates continuously or in increments. The control unit controls the linear driver to move the pressure roller along the preset path based on the real-time rotation angle. At the same time, the pressure sensor provides real-time feedback of the pressure value. The control unit quickly adjusts the driver output through the PID closed-loop control algorithm to offset the changes in working distance caused by changes in the thickness of the yarn wrapping tape and the increase in the number of layers, thus maintaining constant pressure and flattening.

[0033] S4: Curved surface following and compensation: When the pressure roller moves to the slope area corresponding to the corner of the rectangular seat, its universal joint connection structure allows the pressure roller to tilt adaptively and maintain good contact with the slope surface; the elastic roller surface or buffer layer can further absorb minor unevenness, and the control unit can preset a slightly increased target pressure value for the corner area to enhance the flattening effect of this key area.

[0034] S5: Finishing the winding: After the set number of layers is reached, the pressure head module retracts, the winding module stops, the iron core and the end fixing device of the wire wrapping tape are loosened, and the wound coil assembly is removed.

[0035] The entire winding process is broken down into six logically rigorous steps, covering preparation, calibration, winding, monitoring, and material unloading, demonstrating high operability and engineering applicability. In particular, constant pressure control and adaptive rotation mechanisms are clearly defined in S3 and S4, ensuring the reliability of the method under complex working conditions. Visual monitoring and pressure control are organically combined to form an intelligent control closed loop of "perception-decision-execution," enhancing the method's intelligence level.

[0036] Preferably, the PID closed-loop control algorithm includes the following steps:

[0037] Step 1: Synchronous acquisition of multi-sensor data: Acquire real-time readings of pressure sensors, angular position of spindle encoder, lateral position of pressure head fed back by X-axis position encoder, position, speed, and current feedback of Z-axis servo motor, and real-time processing results of vision system;

[0038] Step 2: State estimation: Estimate the true state of the system based on the extended Kalman filter: the optimal estimate of the actual contact pressure, the real-time height of the tape surface, and the magnitude and direction of the disturbances experienced by the system;

[0039] Step 3: Control Error Calculation and Feature Analysis: Calculate the difference between the current pressure and the target pressure. The error analysis module performs in-depth analysis of the error signal, calculates short-term fluctuations and long-term trends to identify error patterns, and predicts future trends based on error characteristics.

[0040] Step 4: Adaptive adjustment of controller parameters: The fuzzy adaptive regulator dynamically adjusts the control parameters according to the error characteristics. When the error is large and changes rapidly, a "fast response mode" with high proportional gain and low integral gain is adopted to quickly eliminate the main error. When the error is small and stable, a "fine adjustment mode" with moderate proportional gain and moderate integral gain is adopted to maintain pressure stability. When continuous oscillation is detected, the derivative gain is automatically increased to introduce damping to suppress oscillation.

[0041] Step 5: Feedforward Compensation Calculation: Based on the accurate geometric model and the current layer number, the system calculates the required compensation amount in advance.

[0042] Floor height compensation: Based on the cumulative number of floors n and the thickness of a single floor t, calculate the theoretical height increment ΔH = n × t;

[0043] Corner compensation: Calculate the slope height variation curve at the corner of the rectangular seat based on the main axis angle θ;

[0044] Speed ​​compensation: Calculate the pressure change trend caused by dynamic effects based on the winding speed;

[0045] The feedforward compensation is directly added to the control output, enabling the system to compensate for errors before they occur.

[0046] Step 6: Robust control law calculation: The adaptive robust pressure controller integrates the processed error signal, the adaptively adjusted PID parameters, the external disturbance estimated by the disturbance observer, and the feedforward compensation input to calculate the final control command.

[0047] Step 7: Multi-axis coordinated motion output: The control command is decomposed into specific commands for each axis. The Z-axis servo electric cylinder receives the pressure control torque command, the X-axis servo module receives the position synchronization command, and keeps the relative position of the pressure head and the winding point constant; the spindle servo motor receives the speed fine-tuning command and adjusts the winding speed according to the pressure feedback.

[0048] A complete control chain, from data fusion and state estimation to parameter adaptation and feedforward compensation, is disclosed, demonstrating the method's technological advancement and feasibility. By fusing and coordinating the control of multi-axis information such as pressure, position, and velocity, the overall performance and response quality of the system are improved. Feedforward compensation, based on model-driven anticipation and combined with feedback control to eliminate errors, significantly improves the system's response speed and control accuracy, especially adapting to altitude changes caused by increasing the number of layers.

[0049] Preferably, when the spindle encoder detects an approach to a corner area, the system enters "corner mode":

[0050] Phase 1: Attitude Adaptation Preparation

[0051] The system reduces the pressure setting value in advance, allowing the pressure roller to adjust its posture more easily when it contacts the inclined surface; at the same time, the locking mechanism of the universal floating joint is released, allowing the pressure roller to deflect freely.

[0052] Phase Two: Incline Follow Control

[0053] When the pressure roller begins to contact the inclined plane, the vision system monitors the contact angle between the pressure roller and the yarn wrapping tape in real time. The system adjusts the control strategy: the pressure control is switched from vertical force control to inclined plane normal force control, the X-axis is given additional compensation motion to assist the pressure roller in smoothly transitioning the angle, and the winding speed is appropriately reduced to give the control system more response time.

[0054] Phase 3: Recovery after turning the corner

[0055] After the pressure roller has fully transitioned to the next plane, the system gradually restores the standard control parameters; the vision system verifies whether the pressure roller posture has returned to normal, and after confirming that there are no errors, the cornering mode is deactivated.

[0056] The cornering process is broken down into three stages: preparation, following, and recovery, each with a corresponding control strategy, systematically solving the industry-wide common problem of poor flattening effect in corner areas. By employing methods such as pre-decompression, posture release, and speed adjustment, the pressure roller ensures a smooth transition at corners, preventing quality defects or mechanical impacts caused by sudden changes. Real-time visual monitoring of the contact angle enables adaptive switching of control strategies, enhancing the intelligence and reliability of corner handling.

[0057] The winding device and method for the primary coil of a current transformer described in this invention have the following advantages:

[0058] 1. Achieved constant pressure precision control: Through closed-loop feedback between pressure sensor and servo drive, the flattening pressure can be precisely stabilized at the set value, avoiding the problems of large pressure fluctuations and lack of fine adjustment in traditional pneumatic methods. It can adapt to silk-wrapped tapes of different specifications and materials, ensuring flattening effect while protecting the insulation layer.

[0059] 2. Improved flattening fit and adaptability: The use of pressure rollers combined with a universal floating structure allows the pressure rollers to better fit the rectangular seat plane and corner slopes, eliminating flattening "blind spots." Elastic roller surfaces or flexible pads reduce the risk of rigid impact and damage.

[0060] 3. Enhanced intelligence and reliability: The introduction of online visual monitoring enables the system to sense the winding quality and automatically adjust parameters or issue warnings based on actual conditions, reducing reliance on operator experience and improving the level of production automation and product consistency.

[0061] 4. Structural optimization and reduced interference: The design of the flexible padding layer reduces the friction and interference between the winding module sidewall and the coil, which is particularly beneficial for multi-layer tight winding. Attached Figure Description

[0062] Fig. 1 This is a schematic diagram of the structure of a winding device for the primary coil of a current transformer according to the present invention.

[0063] Fig. 2 This is a circuit block diagram of a winding device for the primary coil of a current transformer according to the present invention.

[0064] Fig. 3 This is a flowchart of a winding method for the primary coil of a current transformer according to the present invention.

[0065] Fig. 4 This is a flowchart of a PID closed-loop control algorithm according to the present invention;

[0066] Fig. 5 This is a flowchart of a cornering pattern according to the present invention.

[0067] In the diagram: 1. Slider; 2. Pressure head mounting plate; 3. Floating mounting bracket; 4. Linear driver; 5. Linear guide rail; 6. Universal connection structure; 7. Pressure roller. Detailed Implementation

[0068] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0069] like Figs. 1-2 As shown, this invention discloses a winding device for the primary coil of a current transformer, comprising a base, a support, a winding module (including a rectangular base), a core base, and a wire wrapping conveying mechanism mounted on the support. The invention is characterized by further including a flattening mechanism, which comprises an adaptive floating pressure head module, a constant pressure drive and sensing module, and a control unit.

[0070] The adaptive floating pressure head module includes a pressure head mounting plate 2 that can float along a direction perpendicular to the working surface of the winding module, and at least one pressure roller 7 mounted on the pressure head mounting plate 2 via a universal connection structure 6.

[0071] The constant pressure drive and sensing module includes a linear driver 4 for driving the movement of the pressure head mounting plate 2, and a pressure sensor for detecting the pressure applied by the pressure head to the tape in real time.

[0072] The control unit is communicatively connected to the linear actuator 4, the pressure sensor, and the main drive motor that drives the winding module to rotate. Based on the feedback signal from the pressure sensor, the control unit adjusts the linear actuator 4 through closed-loop control to maintain a constant pressure of the pressure head on the yarn wrapping tape; and controls the movement trajectory of the pressure head based on the rotation angle of the winding module.

[0073] The adaptive floating pressure head module adopts a three-layer suspended floating structure, which consists of the following layers from top to bottom: X-axis floating mounting layer, Z-axis floating and driving layer, and pressure roller adaptive suspension layer.

[0074] The X-axis floating mounting layer uses a portal frame (i.e., floating mounting bracket 3) made of high-strength aluminum alloy or steel structure, spanning above the winding module (rectangular base). The columns on both sides of the frame are connected to the slider 1 through high-precision linear guides 5. The Z-axis floating and driving layer is mounted on the slider 1, so that the Z-axis floating and driving layer can be driven by a set of precision servo linear modules in the X-axis direction (parallel to the long side of the rectangular base) to achieve lateral following of the flattening path.

[0075] The servo linear module can be driven by a ball screw, with the screw nut seat rigidly connected to the slider 1 of the linear guide 5 via a mounting plate. The linear guide 5 is responsible for bearing all lateral forces and overturning moments, and ensuring the straightness of the movement; the screw only provides axial driving force and does not bear bending moments. A servo motor or stepper motor drives the screw to rotate, and the nut meshing with the screw, being prevented from rotating (usually fixedly connected to the slider 1), converts the rotational motion into linear motion, thereby driving the slider 1 to move along the linear guide 5.

[0076] The Z-axis floating and driving layer is the core of realizing vertical (Z-axis) floating and active pressure control. It adopts a linear actuator 4 and is mounted on the slider 1 through the pressure head mounting plate 2.

[0077] The adaptive suspension layer of the pressure roller, acting as the working end actuator, directly contacts the yarn-wrapped tape and is installed below the Z-axis floating and driving layer, playing a crucial role in achieving "adaptive" fit. The pressure head mounting plate 2 is a lightweight alloy plate connected to the linear actuator 4 via a pressure sensor. The universal joint structure 6 uses a compact spherical bearing pair or a cross-hing mechanism as the first-stage float. This joint allows the pressure roller 7 to freely deflect within ±15° around its mounting point to accommodate the inclined surface at the corner of the rectangular seat. A miniature linear bearing is added between the universal joint structure 6 and the axis of the pressure roller 7, allowing for a slight axial float of ±2mm on the pressure roller 7. This design compensates for minor height differences when different parts of the same pressure roller 7 contact different layer heights, ensuring uniform contact along the entire length of the pressure roller 7.

[0078] The core of pressure roller 7 is made of high-rigidity stainless steel or alloy steel shaft, and both ends are mounted on the Z-axis floating and driving layer via precision bearings. Elastic coating layer:

[0079] a) Outer layer: Abrasion-resistant, high-friction coefficient polyurethane (PU) or silicone rubber, with Shore hardness selectable according to the tape hardness (e.g., 60A-80A). The soft layer better conforms to the surface and absorbs minor unevenness.

[0080] b) Intermediate buffer layer (optional): A layer of foamed silicone or high-damping rubber can be added between the inner and outer layers to further absorb high-frequency vibrations and impacts, achieving a "soft landing".

[0081] The surface of the pressure roller can be processed with fine anti-slip texture or polished to avoid scratching the insulation layer of the tape while providing sufficient traction.

[0082] like Figs. 3-5 As shown, the present invention also discloses a winding method for the primary coil of a current transformer, comprising:

[0083] S1: Winding preparation and parameter setting: Install the rectangular base of the corresponding specification and clamp the iron core; according to the material, thickness and coil process requirements of the wire wrapping tape, set the winding speed, target pressure value and pressure adjustment threshold in the control unit;

[0084] S2: Initial winding and pressure calibration: Start winding, and fix the first end of the wrapped tape to the rectangular base; the winding module starts to rotate, and the constant pressure drive and sensing module drive the adaptive floating pressure head module to approach the wrapped tape; when the pressure sensor detects that the contact pressure has reached the preset initial value, the control unit records the current position as the flattening start reference point and enters the constant pressure control mode;

[0085] S3: Constant pressure adaptive winding: The winding module rotates continuously or in increments. The control unit controls the linear driver 4 to move the pressure roller 7 along the preset path according to the real-time rotation angle. At the same time, the pressure sensor provides real-time feedback of the pressure value. The control unit quickly adjusts the driver output through the PID closed-loop control algorithm to offset the changes in working distance caused by changes in the thickness of the yarn wrapping tape and the increase in the number of layers, and maintains constant pressure flattening.

[0086] S4: Curved surface following and compensation: When the pressure roller 7 moves to the slope area corresponding to the corner of the rectangular seat, its universal joint connection structure 6 allows the pressure roller 7 to tilt adaptively and maintain good contact with the slope surface; the elastic roller surface or buffer layer can further absorb minor unevenness, and the control unit can preset a slightly increased target pressure value for the corner area to enhance the flattening effect of this key area.

[0087] S5: Finishing the winding: After the set number of layers is reached, the pressure head module retracts, the winding module stops, the iron core and the end fixing device of the wire wrapping tape are loosened, and the wound coil assembly is removed.

[0088] The PID closed-loop control algorithm includes the following steps:

[0089] Step 1: Synchronous acquisition of multi-sensor data: Acquire real-time readings of the pressure sensor, the angular position of the spindle encoder, the lateral position of the pressure head fed back by the X-axis position encoder, the position, speed, and current feedback of the Z-axis servo motor, and the real-time processing results of the vision system.

[0090] Step 2: State estimation: Estimate the true state of the system based on the extended Kalman filter: the optimal estimate of the actual contact pressure, the real-time height of the tape surface, and the magnitude and direction of the disturbances experienced by the system.

[0091] Step 3: Control Error Calculation and Feature Analysis: Calculate the difference between the current pressure and the target pressure. The error analysis module performs in-depth analysis of the error signal, calculates short-term fluctuations and long-term trends to identify error patterns, and predicts future trends based on error characteristics.

[0092] Specifically,

[0093] 301. Error Calculation: In each control cycle kT (e.g., T=1ms), calculate the current pressure error e(k):

[0094] e(k) = P_target - P_actual(k)

[0095] 302. PID control quantity calculation (incremental type):

[0096] text

[0097] Δu(k)=Kp*[e(k)-e(k-1)]+Ki*T*e(k)+Kd / T*[e(k)-2e(k-1)+e(k-2)]

[0098] u(k) = u(k-1) + Δu(k)

[0099] in:

[0100] Δu(k): The increment of the control quantity in the current control cycle;

[0101] u(k): The control quantity output to the servo drive in the current cycle (e.g., percentage of torque command or additional position fine-tuning).

[0102] Kp, Ki, Kd: proportional, integral, and differential gain coefficients;

[0103] e(k-1), e(k-2): Pressure errors of the previous one and the previous two cycles.

[0104] 303. Parameter Tuning Strategy:

[0105] Proportional gain Kp: Set a large value to provide a fast response and quickly offset the instantaneous pressure drop caused by the stacking of new layers of tape. However, an upper limit is required to prevent overshoot and pressure shock.

[0106] Integral gain Ki: Set an appropriate value to eliminate static errors. For example, after winding multiple layers, the pressure roller 7 needs to be continuously raised to a certain height to compensate for the accumulated thickness. The integral term can continuously output control quantity to drive the pressure roller 7 to slowly follow the working surface and maintain constant pressure.

[0107] Differential gain Kd: Set a small value to suppress oscillations during rapid pressure changes. Since the surface of the yarn wrapping tape is not perfectly rigid and there may be slight jumps during the winding process, the differential term helps to smooth the control.

[0108] Adaptive tuning: The controller can have multiple sets of PID parameters built in. For example:

[0109] Parameter group A (Initial contact / interlayer transition): Kp is large, Ki is medium, used for rapid pressure establishment and recovery.

[0110] Parameter group B (steady-state winding): Kp is medium, Ki is small, and Kd is fine-tuned. This is used to maintain pressure stability in the flat section and reduce unnecessary adjustment actions.

[0111] The control unit can automatically switch parameter groups according to the magnitude and rate of change of the error e(k), or use advanced algorithms such as fuzzy PID to fine-tune the parameters online.

[0112] Step 4: Adaptive adjustment of controller parameters: The fuzzy adaptive regulator dynamically adjusts the control parameters according to the error characteristics. When the error is large and changes rapidly, a "fast response mode" with high proportional gain and low integral gain is adopted to quickly eliminate the main error. When the error is small and stable, a "fine adjustment mode" with moderate proportional gain and moderate integral gain is adopted to maintain pressure stability. When continuous oscillation is detected, the derivative gain is automatically increased to introduce damping to suppress oscillation.

[0113] Step 5: Feedforward Compensation Calculation: Based on the accurate geometric model and the current layer number, the system calculates the required compensation amount in advance.

[0114] Floor height compensation: Based on the cumulative number of floors n and the thickness of a single floor t, calculate the theoretical height increment ΔH = n × t;

[0115] Corner compensation: Calculate the slope height variation curve at the corner of the rectangular seat based on the main axis angle θ;

[0116] Speed ​​compensation: Calculate the pressure change trend caused by dynamic effects based on the winding speed;

[0117] The feedforward compensation is directly added to the control output, enabling the system to compensate for errors before they occur.

[0118] To more accurately offset the changes in systematic working distance caused by the increase in the number of layers and improve the response speed, feedforward control is introduced on the basis of PID feedback closed loop.

[0119] 501. Construction of the feedforward channel:

[0120] Thickness accumulation model: The controller internally maintains a model of "theoretical number of winding layers n" and "cumulative theoretical thickness of the tape H_total(n)". H_total(n) = n*t_nom + δ, where t_nom is the nominal thickness of the tape and δ is the empirical compensation amount after compression (which can be learned).

[0121] Rotation angle synchronization: The controller reads the rotation angle θ of the winding module fed back by the spindle encoder in real time.

[0122] Feedforward Calculation: When winding to the nth layer, for a given rotation angle θ, the theoretical height change ΔH(n,θ) of the rectangular seat working surface relative to the initial position can be pre-calculated or obtained through a geometric model (the height of the planar segment is H_total(n), and the height of the corner ramp segment changes continuously). This height change ΔH is multiplied by a feedforward gain Kff (related to system stiffness, etc.) and directly converted into a position compensation command or an additional torque bias command for the precision linear actuator.

[0123] 502. Composite control output:

[0124] The final integrated control instruction U_final(k) output to the servo driver is:

[0125] U_final(k)=u_PID(k)+u_ff(θ,n)

[0126] Where u_PID(k) is the output of the PID feedback controller mentioned above, and u_ff(θ,n) is the feedforward compensation amount based on angle and number of layers.

[0127] Before pressure errors are detected, the feedforward term proactively compensates for predictable changes in working distance caused by the increase in the number of layers and the winding trajectory, greatly reducing the adjustment burden on the PID feedback loop. The feedback term (PID) focuses on handling unpredictable disturbances, such as the thickness inhomogeneity of the tape itself, minor deformations, and material elasticity fluctuations, ensuring precise and constant pressure.

[0128] Step 6: Robust control law calculation: The adaptive robust pressure controller integrates the processed error signal, the adaptively adjusted PID parameters, the external disturbance estimated by the disturbance observer, and the feedforward compensation input to calculate the final control command.

[0129] Step 7: Multi-axis coordinated motion output: The control command is decomposed into specific commands for each axis. The Z-axis servo electric cylinder receives the pressure control torque command, the X-axis servo module receives the position synchronization command, and keeps the relative position of the pressure head and the winding point constant; the spindle servo motor receives the speed fine-tuning command and adjusts the winding speed according to the pressure feedback.

[0130] When the spindle encoder detects an approach to a corner area, the system enters "corner mode":

[0131] Phase 1: Attitude Adaptation Preparation

[0132] The system reduces the pressure setting value in advance, allowing the pressure roller to adjust its posture more easily when it contacts the inclined surface; at the same time, the locking mechanism of the universal floating joint 6 is released, allowing the pressure roller 7 to deflect freely.

[0133] Phase Two: Incline Follow Control

[0134] When the pressure roller 7 begins to contact the inclined plane, the vision system monitors the contact angle between the pressure roller 7 and the yarn wrapping tape in real time. The system adjusts the control strategy: the pressure control is switched from vertical force control to inclined plane normal force control, and additional compensation motion is added to the X-axis to assist the pressure roller 7 in smoothly transitioning the angle. The winding speed is appropriately reduced to give the control system more response time.

[0135] Phase 3: Recovery after turning the corner

[0136] After the pressure roller 7 has fully transitioned to the next plane, the system gradually restores the standard control parameters; the vision system verifies whether the posture of the pressure roller 7 has returned to normal, and after confirming that there are no errors, the cornering mode is deactivated.

[0137] Precise closed-loop pressure control was achieved through a combination of pressure sensors, servo drives, and intelligent algorithms, solving the technical challenge of dynamically adapting to changes in materials and layer counts to maintain optimal flattening force. The use of a universal connection structure (6) and an elastic pressure roller (7) addressed the technical challenge of enabling the flattening tool to better conform to complex winding surfaces (especially corners). The introduction of visual monitoring enabled online perception and adaptive adjustment of process quality. These technologies produced a synergistic effect greater than the sum of its parts, resulting in unexpected improvements in flattening quality, enhanced process adaptability, and higher levels of automation. This demonstrates significant substantive characteristics and substantial progress, meeting creative requirements.

[0138] To achieve better results, online monitoring and adjustment can be added between S4 and S5: the vision inspection unit periodically captures images of the winding surface, and the control unit analyzes the images. If wrinkles or gaps are detected, the target pressure value is automatically increased slightly; if severe offset or abnormal bulging of the tape edge is detected, a pause and alarm are triggered.

[0139] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A winding device for the primary coil of a current transformer, comprising a base, a support, a winding module mounted on the support, a core holder, and a wire wrapping conveying mechanism, characterized in that, It also includes a flattening mechanism, which comprises an adaptive floating pressure head module, a constant pressure drive and sensing module, and a control unit. The adaptive floating pressure head module includes a pressure head mounting plate (2) that can float along a direction perpendicular to the working surface of the winding module, and at least one pressure roller (7) mounted on the pressure head mounting plate (2) via a universal connection structure (6); The constant pressure drive and sensing module includes a linear driver (4) for driving the movement of the pressure head mounting plate (2), and a pressure sensor for detecting the pressure applied by the pressure head to the tape in real time; The control unit is communicatively connected to the linear actuator (4), the pressure sensor and the main drive motor that drives the winding module to rotate. Based on the feedback signal of the pressure sensor, the control unit adjusts the linear actuator (4) through closed-loop control to maintain a constant pressure of the pressure head on the tape; and controls the movement trajectory of the pressure head based on the rotation angle of the winding module.

2. A winding device for the primary coil of a current transformer according to claim 1, characterized in that, The pressure head mounting plate (2) is set on the floating mounting frame (3), which can move in a direction parallel to the working surface of the winding module to achieve lateral following of the flattening path.

3. A winding device for the primary coil of a current transformer according to claim 2, characterized in that, The roller surface of the pressure roller (7) is made of elastic material, or the pressure roller (7) has an elastic buffer layer inside.

4. A winding device for the primary coil of a current transformer according to claim 2, characterized in that, The control unit is a PLC controller.

5. A winding device for the primary coil of a current transformer according to claim 1, characterized in that, The working sidewall of the winding module is covered with a flexible padding layer.

6. A winding method for a winding device for the primary coil of a current transformer as described in any one of claims 1-5, characterized in that, include: Set the target pressure value according to the specifications of the tape. Start the winding process, control the pressure roller (7) to contact the yarn wrapping tape and reach the initial pressure, and enter the constant pressure control mode; During the winding process of the winding module, the feedback value of the pressure sensor is monitored in real time, and the linear driver (4) is dynamically adjusted through closed-loop control so that the actual pressure of the pressure roller (7) on the yarn package is maintained near the target pressure value. The motion path of the pressure roller (7) is controlled to match the winding trajectory.

7. The winding method according to claim 6, characterized in that, Specifically, the following steps are included: S1: Winding preparation and parameter setting: Install the rectangular base of the corresponding specification and clamp the iron core; according to the material, thickness and coil process requirements of the wire wrapping tape, set the winding speed, target pressure value and pressure adjustment threshold in the control unit; S2: Initial winding and pressure calibration: Start winding, and fix the first end of the wrapped tape to the rectangular base; the winding module starts to rotate, and the constant pressure drive and sensing module drive the adaptive floating pressure head module to approach the wrapped tape; when the pressure sensor detects that the contact pressure has reached the preset initial value, the control unit records the current position as the flattening start reference point and enters the constant pressure control mode; S3: Constant pressure adaptive winding: The winding module rotates continuously or in increments. The control unit controls the linear driver (4) to move the pressure roller (7) along the preset path according to the real-time rotation angle. At the same time, the pressure sensor provides real-time feedback of the pressure value. The control unit quickly adjusts the driver output through the PID closed-loop control algorithm to offset the changes in working distance caused by the change in the thickness of the yarn wrapping tape and the increase in the number of layers, and maintains constant pressure flattening. S4: Curved surface following and compensation: When the pressure roller (7) moves to the slope area corresponding to the corner of the rectangular seat, its universal connection structure (6) allows the pressure roller (7) to tilt adaptively and maintain good contact with the slope surface; the elastic roller surface or buffer layer can further absorb minor unevenness, and the control unit can preset a slightly increased target pressure value for the corner area to enhance the flattening effect of this key area. S5: Finishing the winding: After the set number of layers is reached, the pressure head module retracts, the winding module stops, the iron core and the end fixing device of the wire wrapping tape are loosened, and the wound coil assembly is removed.

8. The winding method according to claim 7, characterized in that, The PID closed-loop control algorithm includes the following steps: Step 1: Synchronous acquisition of multi-sensor data: Acquire real-time readings of pressure sensors, angular position of spindle encoder, lateral position of pressure head fed back by X-axis position encoder, position, speed, and current feedback of Z-axis servo motor, and real-time processing results of vision system; Step 2: State estimation: Estimate the true state of the system based on the extended Kalman filter: the optimal estimate of the actual contact pressure, the real-time height of the tape surface, and the magnitude and direction of the disturbances experienced by the system; Step 3: Control Error Calculation and Feature Analysis: Calculate the difference between the current pressure and the target pressure. The error analysis module performs in-depth analysis of the error signal, calculates short-term fluctuations and long-term trends to identify error patterns, and predicts future trends based on error characteristics. Step 4: Adaptive adjustment of controller parameters: The fuzzy adaptive regulator dynamically adjusts the control parameters according to the error characteristics. When the error is large and changes rapidly, a "fast response mode" with high proportional gain and low integral gain is adopted to quickly eliminate the main error. When the error is small and stable, a "fine adjustment mode" with moderate proportional gain and moderate integral gain is adopted to maintain pressure stability. When continuous oscillation is detected, the derivative gain is automatically increased to introduce damping to suppress oscillation. Step 5: Feedforward Compensation Calculation: Based on the accurate geometric model and the current layer number, the system calculates the required compensation amount in advance. Floor height compensation: Based on the cumulative number of floors n and the thickness of a single floor t, calculate the theoretical height increment ΔH = n × t; Corner compensation: Calculate the slope height variation curve at the corner of the rectangular seat based on the main axis angle θ; Speed ​​compensation: Calculate the pressure change trend caused by dynamic effects based on the winding speed; The feedforward compensation is directly added to the control output, enabling the system to compensate for errors before they occur. Step 6: Robust control law calculation: The adaptive robust pressure controller integrates the processed error signal, the adaptively adjusted PID parameters, the external disturbance estimated by the disturbance observer, and the feedforward compensation input to calculate the final control command. Step 7: Multi-axis coordinated motion output: The control command is decomposed into specific commands for each axis. The Z-axis servo electric cylinder receives the pressure control torque command, the X-axis servo module receives the position synchronization command, and keeps the relative position of the pressure head and the winding point constant; the spindle servo motor receives the speed fine-tuning command and adjusts the winding speed according to the pressure feedback.

9. The winding method according to claim 8, characterized in that, When the spindle encoder detects an approach to a corner area, the system enters "corner mode": Phase 1: Attitude Adaptation Preparation The system reduces the pressure setting value in advance, allowing the pressure roller (7) to adjust its posture more easily when it contacts the inclined plane; at the same time, the locking mechanism of the universal connection structure (6) is released, allowing the pressure roller (7) to deflect freely; Phase Two: Incline Follow Control When the pressure roller (7) begins to contact the inclined plane, the vision system monitors the contact angle between the pressure roller (7) and the yarn wrapping tape in real time. The system adjusts the control strategy: the pressure control is switched from vertical force control to inclined plane normal force control, and the X-axis adds additional compensation motion to assist the pressure roller (7) in smoothly transitioning the angle, appropriately reducing the winding speed, and giving the control system more response time. Phase 3: Recovery after turning the corner After the pressure roller (7) has completely transitioned to the next plane, the system gradually restores the standard control parameters; the vision system verifies whether the posture of the pressure roller (7) has returned to normal, and after confirming that there are no errors, the cornering mode is deactivated.

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