A high-pressure roller mill dynamic fixed roller current automatic compensation control method

Abstract

The application discloses a kind of high-pressure roll mill dynamic fixed roller current automatic compensation control methods, it is related to the control technical field of grinding equipment, the dynamic roller body and fixed roller body of high-pressure roll mill are respectively driven by the drive motor with frequency converter configuration, and the feed hopper both sides are respectively equipped with including hydraulic cylinder, distribution plate and displacement sensor distribution device.The method is to the current of both sides drive motor sliding average and is confirmed to inhibit the instantaneous fluctuation of feeding false trigger by combining duration;Dead zone band, grading proportion coefficient and single step stroke limiting amplitude are combined to approach balance by the step compensation of grading dead zone;Unit stroke current response coefficient is corrected on-line self-learning to adapt to roll skin wear and tear and the like working conditions, and compensation precision is improved;And the sum of both sides hydraulic cylinder stroke and response coefficient decay rate are combined to reliably prompt roll skin replacement by two-parameter joint criterion.The application realizes both sides current automatic, accurate, stable balance, reduces the dependence on artificial experience, prolongs the life of core component and reduces energy consumption.

Description

Technical Field

[0001] This invention relates to the field of grinding equipment control technology, specifically to an automatic compensation control method for the current of the moving and stationary rollers in a high-pressure roller mill. Background Technology

[0002] High-pressure roller mills are grinding equipment based on the principle of material layer compression and crushing. They feature low energy consumption, good particle shape, high output, compact footprint, and stable operation, and are widely used in building materials, metal mines, and solid waste resource treatment. A high-pressure roller mill mainly consists of a frame, moving rollers, fixed rollers, a feed hopper, a pressure application device, and a transmission device. During operation, material is fed between the two rollers through the feed hopper. A large number of particles accumulate between the moving and fixed rollers, forming a dense material layer. Overall crushing is achieved through the mutual pressure and stress transmission between the particles.

[0003] In a high-pressure roller mill, the moving and stationary rollers are typically driven by independent motors. Initially, the material layer on both rollers is relatively uniform, the load on both sides is relatively balanced, and the currents of the motors driving the moving and stationary rollers remain relatively balanced. At this point, the finished product quality and production efficiency are ideal, and energy efficiency is high. However, after the equipment has been running for a period of time, factors such as roller wear and uneven feeding cause the material layer on the moving and stationary rollers to become uneven, resulting in an imbalance in the load on both sides and causing one motor to have a higher current than the other. This long-term imbalance in current will accelerate the wear of core components such as bearings and reducers, shorten their lifespan, reduce production efficiency and finished product quality, increase system energy consumption, and lead to frequent equipment shutdowns. To balance the currents, the distribution of the feed on the two rollers needs to be adjusted by changing the amount of material accumulated on the moving and stationary rollers to balance the load on both sides.

[0004] In the prior art, CN201399352Y discloses a roller press to improve feed distribution. It installs an electric lifting device and an inclined plate on each side of the feed hopper, and controls the feed flow rate and improve the material engagement between the two rollers by controlling the opening size of the inclined plate via computer. However, this solution only aims to fill the roller gap and improve engagement by controlling the feed rate, without addressing the detection and closed-loop balancing of the current of the drive motors on both sides, thus failing to solve the problem of current imbalance during operation. CN103492079A discloses a method for adjusting the roller gap pressure of a roller press, which adjusts the roller gap pressure by detecting the vibration of the roller press as the adjustment input value. However, its adjustment target is the roller gap pressure, not the current on both sides, and it does not address the differential adjustment of the material layer distribution on both sides.

[0005] Furthermore, existing methods for adjusting the current on both sides of a roller mill mainly rely on manual adjustments of the inclined plate or the material distribution mechanism multiple times. This is not only cumbersome but also requires a high level of skill and experience from the operators. The adjustments are time-consuming, inefficient, and the results vary from person to person, exhibiting poor stability. Even if the material distribution mechanism is replaced with automatic adjustment, if a one-time linear extrapolation adjustment is made based solely on the current difference and a fixed unit stroke current response, problems such as overshoot, back-and-forth oscillation, and inaccurate compensation may occur due to factors such as lag in material accumulation and transmission, and changes in the unit stroke current response over time caused by roller wear. At the same time, judging whether the roller needs to be replaced based solely on the absolute value of the stroke of the material distribution mechanism on one side is easily affected by fluctuations in the feeding conditions, leading to misjudgments.

[0006] Therefore, a control method is needed that can automatically, accurately, and stably balance the current of the drive motors on both sides of a high-pressure roller mill and reliably indicate when to replace the roller skin. Summary of the Invention

[0007] To address the shortcomings of the existing technologies, this invention provides an automatic compensation control method for the motor current of a high-pressure roller mill. By filtering and confirming the current of the drive motors on both sides, performing graded dead zone step compensation, and online self-learning correction of the unit stroke current response coefficient, the method achieves automatic, accurate, and stable balance of the current on both sides. Furthermore, it reliably prompts for roller skin replacement through a dual-parameter joint criterion, overcoming the problems of low efficiency of manual adjustment and easy overshoot oscillation and inaccurate compensation in simple linear compensation.

[0008] To achieve the above objectives, the present invention adopts the following technical solution.

[0009] An automatic compensation control method for the moving and stationary roller current of a high-pressure roller mill is disclosed. The moving and stationary rollers of the high-pressure roller mill are driven by a moving roller drive motor and a stationary roller drive motor, respectively. Each of the moving and stationary roller drive motors is equipped with a frequency converter, which detects the current of the corresponding drive motor in real time. A material distribution device is provided on both sides of the feed hopper of the high-pressure roller mill. The material distribution device includes a hydraulic cylinder, a material distribution plate, and a displacement sensor. The hydraulic cylinder is connected to the material distribution plate through a connecting seat and drives the material distribution plate to reciprocate to change the feed distribution on the corresponding side. The displacement sensor detects the current stroke of the hydraulic cylinder on the corresponding side. The control method includes the following steps: Step 1: The first current I1 of the moving roller drive motor and the second current I2 of the stationary roller drive motor are collected in real time by the frequency converter. The control module performs sliding average on the first current I1 and the second current I2 within the set filtering time window to obtain the first average current and the second average current. Step two, the control module calculates the current difference ΔI between the first average current and the second average current. When the current difference ΔI is greater than the preset current difference threshold ΔI... 设If the duration reaches the set confirmation time, it is determined that the current on both sides is unbalanced and proceeds to step three; otherwise, it is determined to be a momentary fluctuation in the feed and returns to step one. Step 3: The control module determines the high current side and the low current side based on the magnitude of the first average current and the second average current, and identifies the dispensing device corresponding to the side with the higher current as the target dispensing device to be adjusted. Step four: The control module determines the target adjustment stroke for this compensation based on the current current difference ΔI and the current unit stroke current response coefficient k, and classifies and limits the target adjustment stroke to obtain the single-step stroke increment Δs. The control module then controls the hydraulic cylinder of the target material distribution device to advance by the single-step stroke increment Δs, thereby reducing the feed amount and thinning the material layer on the high current side, thus reducing the current of the high current side drive motor. The unit stroke current response coefficient k is the change in the current of the corresponding side drive motor caused by each unit stroke of the hydraulic cylinder. Step 5: After the hydraulic cylinder completes the single-step stroke increment Δs and after the set stabilization waiting time, the control module re-acquires and calculates the current difference ΔI, and updates the unit stroke current response coefficient k online according to the actual current change caused by the single-step stroke increment Δs. Step 6: Determine whether the updated current difference ΔI is still greater than the current difference threshold ΔI. 设 If yes, return to step three to continue the next compensation; otherwise, the current compensation is complete, and return to step one. Step 7: The control module obtains the current stroke of the hydraulic cylinders on both sides. When the sum of the current strokes of the hydraulic cylinders on both sides is greater than the preset stroke and threshold, and the attenuation rate of the unit stroke current response coefficient k relative to its initial value is greater than the preset attenuation rate threshold, the control module outputs a roller skin replacement prompt signal.

[0010] Furthermore, in step one, the moving average is the arithmetic average of the current sample values ​​collected within the filtering time window, and the duration of the filtering time window is from 1 second to 5 seconds.

[0011] Furthermore, in step two, the confirmation time is set to 3 to 10 seconds; when the current difference ΔI is greater than the current difference threshold ΔI... 设 If the duration of the state does not reach the confirmation time, the control module will not trigger compensation.

[0012] Furthermore, in step three, if the current stroke of the hydraulic cylinder of the other side of the target material distribution device is greater than zero, then while controlling the hydraulic cylinder of the target material distribution device to move forward, the hydraulic cylinder of the other side of the material distribution device is controlled to retreat by the same single-step stroke increment, so that the feed amount on the other side increases and the material layer thickens; if the hydraulic cylinder of the other side of the material distribution device is at zero stroke, then the hydraulic cylinder of the other side of the material distribution device does not retreat.

[0013] Further, in step four, the step of classifying and limiting the target adjustment stroke includes: setting a dead zone, several current difference ranges, and a compensation ratio coefficient corresponding to each range, wherein the compensation ratio coefficient increases as the current difference range increases; when the current difference ΔI falls within the dead zone, the single-step stroke increment Δs is zero; when the current difference ΔI is greater than the upper limit of the dead zone, the corresponding compensation ratio coefficient α is selected according to the range where the current difference ΔI is located, the target adjustment stroke is calculated, and the target adjustment stroke is compared with the preset single-step stroke upper limit, and the smaller of the two is taken as the single-step stroke increment Δs.

[0014] Furthermore, in step four, the upper limit of the dead zone is not greater than the current difference threshold ΔI. 设 The upper limit of the single-step travel is 5mm to 30mm.

[0015] Further, in step five, the online update of the unit stroke current response coefficient k includes: recording the change Δi of the current of the drive motor on the corresponding side of the target material distribution device before and after this compensation, calculating the measured unit stroke current response value Δi of this compensation divided by the single-step stroke increment Δs, and using a first-order inertial filtering method, weighting the measured unit stroke current response value with the unit stroke current response coefficient k before the update according to the set update weight to obtain the updated unit stroke current response coefficient k.

[0016] Furthermore, the connecting seat is threadedly connected to the hydraulic cylinder, and the hydraulic cylinder is mounted on the upper side of the feed hopper by screws. The material distribution plate is placed between the roller and the slide. During operation, the hydraulic cylinder drives the material distribution plate to move on the roller. The displacement sensor is set on the parallel side of the hydraulic cylinder and connected to the material distribution plate to synchronously detect the current stroke of the hydraulic cylinder.

[0017] The beneficial effects of this invention are as follows: 1. This invention uses a sliding average filter on the current of the two drive motors and combines it with the duration confirmation. Compensation is only triggered when the current difference exceeds the threshold and lasts for a sufficient time. This effectively suppresses false triggering caused by instantaneous fluctuations in the on-site feeding and avoids frequent invalid actions of the material distribution device.

[0018] 2. This invention adopts a graded dead zone step compensation strategy that combines dead zone, graded proportional coefficient and single-step amplitude limiting. Each compensation is performed with a limited step length and is re-checked and iterated after stabilization. This overcomes the adjustment overshoot and back-and-forth oscillation caused by the lag in the transmission of material layer accumulation in simple linear extrapolation compensation, so that the current on both sides tends to be balanced smoothly.

[0019] 3. This invention performs online self-learning correction on the unit stroke current response coefficient, enabling the compensation amount to automatically adapt to working conditions such as roller wear and changes in material characteristics. This overcomes the problem of inaccurate compensation caused by a fixed unit stroke current response amount and improves the compensation accuracy.

[0020] 4. This invention uses a dual-parameter joint criterion combining the sum of the strokes of the hydraulic cylinders on both sides and the attenuation rate of the current response coefficient per unit stroke to indicate the replacement of the roller skin. Compared with judging solely by the absolute value of the stroke on one side, this invention can more realistically reflect the overall wear state of the roller skin, reduce misjudgments, and provide a reliable basis for timely replacement of the roller skin.

[0021] 5. This invention achieves fully automatic compensation of current on both sides, eliminating the need for repeated manual adjustments, reducing reliance on operator experience, improving adjustment efficiency and consistency, extending the lifespan of core components, and reducing system energy consumption. Attached Figure Description

[0022] Figure 1 This is a flowchart of the control method of the present invention; Figure 2 This is a schematic diagram of the overall structure of the high-pressure roller mill of the present invention; Figure 3 This is a schematic diagram of the working area of ​​the high-pressure roller mill of the present invention; Figure 4 This is a schematic diagram of the feed hopper assembly of the present invention; In the diagram: 1. Feed hopper; 2. Moving roller; 3. Fixed roller; 4. Moving roller drive motor; 5. Fixed roller drive motor; 8. Hydraulic cylinder; 9. Distributor plate; 10. Connecting seat; 11. Displacement sensor; 12. Roller; 13. Slide chute; 14. Hydraulic station. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited thereto.

[0024] like Figures 2 to 4 As shown, the high-pressure roller mill in this embodiment includes a frame, a feed hopper 1, a moving roller body 2, and a fixed roller body 3. The moving roller body 2 is driven by a moving roller body drive motor 4, and the fixed roller body 3 is driven by a fixed roller body drive motor 5. The moving roller body drive motor 4 and the fixed roller body drive motor 5 are each equipped with a frequency converter. The frequency converter detects the current of the corresponding drive motor in real time and transmits the current data to the control module.

[0025] A material distribution device is provided on each side of the feed hopper 1, corresponding to one side of the moving roller 2 and the other side of the fixed roller 3. Each material distribution device includes a hydraulic cylinder 8, a material distribution plate 9, and a displacement sensor 11. The hydraulic cylinder 8 is mounted on the upper side of the feed hopper 1 with screws, and the piston rod of the hydraulic cylinder 8 is threadedly connected to the material distribution plate 9 through a connecting seat 10. The material distribution plate 9 is positioned between the roller 12 and the slide groove 13. During operation, the hydraulic cylinder 8 drives the material distribution plate 9 to reciprocate on the roller 12, thereby changing the distribution of the feed material on the corresponding side of the roller. The displacement sensor 11 is located on the parallel side of the hydraulic cylinder 8 and connected to the material distribution plate 9, synchronously detecting the current stroke of the hydraulic cylinder 8. The hydraulic cylinders 8 of the two material distribution devices are driven by oil supplied by a hydraulic station 14.

[0026] The material distribution device on the side corresponding to the moving roller 2 is designated as the first material distribution device, and the material distribution device on the side corresponding to the fixed roller 3 is designated as the second material distribution device. The current of the moving roller drive motor 4 is designated as the first current I1, and the current of the fixed roller drive motor 5 is designated as the second current I2. In the initial state, both hydraulic cylinders 8 are at zero stroke, and the material distribution plate 9 does not obstruct the feeding. At this time, the material layers on both sides are relatively uniform.

[0027] like Figure 1 As shown, this embodiment provides an automatic compensation control method for the current of moving and stationary rollers, including the following steps: Step 1: The control module collects the first current I1 and the second current I2 in real time via the frequency converter. The control module then performs a moving average on the first current I1 and the second current I2 within a set filtering time window. In this embodiment, the filtering time window is 2 seconds. The control module calculates the arithmetic mean of the current samples collected within 2 seconds to obtain the first average current I. 1a Second average current I 2a The moving average method can filter out high-frequency current fluctuations caused by feed pulsation and instantaneous particle jamming, allowing subsequent judgments to be based on stable current values.

[0028] Step 2: The control module calculates the current difference ΔI, ΔI = |I 1a -I 2a The control module determines whether the current difference ΔI is greater than the preset current difference threshold ΔI. 设 In this embodiment, ΔI 设 =30A. When the current difference ΔI is greater than ΔI 设 Furthermore, when the duration of this state reaches the set confirmation time, an imbalance in the currents on both sides is determined, and step three is initiated; in this embodiment, the confirmation time is 5 seconds. If the current difference ΔI is not greater than ΔI... 设 , or although greater than ΔI 设 However, if the duration does not reach the confirmation time, it is determined to be a momentary fluctuation in the feed, the control module does not trigger compensation, and returns to step one, allowing the equipment to operate normally. By confirming the duration, malfunctions of the dispensing device caused by occasional short-term current spikes are avoided.

[0029] Step 3: The control module compares the first average current I. 1a Second average current I 2a The size of I determines the high current side and the low current side, and the dispensing device corresponding to the high current side is selected as the target dispensing device. 1a Greater than I 2a If the current is higher on the side of the moving roller 2, the first material distribution device is identified as the target material distribution device; if I 1a Less than I 2a If the current is higher on one side of the fixed roller body 3, the second material distribution device will be identified as the target material distribution device.

[0030] Step four: The control module determines the target adjustment stroke for this compensation based on the current current difference ΔI and the current unit stroke current response coefficient k, and performs grading and single-step limiting to obtain the single-step stroke increment Δs. The unit stroke current response coefficient k is the change in the current of the corresponding side drive motor caused by each unit stroke forward of the hydraulic cylinder 8. Its initial value k0 is set according to the equipment debugging data. In this embodiment, k0 is taken as 0.67A / mm, that is, the current on the corresponding side changes by about 1A for every 1.5mm forward of the hydraulic cylinder 8.

[0031] The specific process of graded and single-step limiting is as follows: The control module sets the dead zone, several current difference ranges, and the corresponding compensation ratio coefficient for each range. In this embodiment, the upper limit of the dead zone is 25A, and it is not greater than the current difference threshold ΔI. 设 Three current differential ranges are set: greater than 25A and not greater than 50A, greater than 50A and not greater than 100A, and greater than 100A. The corresponding compensation ratio coefficients α are 0.5, 0.7, and 0.9, respectively. The compensation ratio coefficient increases with the increase of the current differential range. The upper limit of the single-step travel is 20mm.

[0032] When the current difference ΔI falls within the dead zone (i.e., not exceeding 25A), the single-step stroke increment Δs is zero, and no compensation is performed to avoid fine-tuning around the equilibrium point. When the current difference ΔI exceeds the upper limit of the dead zone, the control module first calculates the theoretical current adjustment required to make the currents on both sides equal, which is half of the current difference ΔI, ΔI / 2. Then, based on the current response coefficient k per unit stroke, it calculates the theoretical stroke required to achieve this theoretical current adjustment, i.e., ΔI / 2 divided by k. Next, it discounts the theoretical stroke according to the compensation ratio coefficient α corresponding to the current difference ΔI's range, obtaining the target adjustment stroke Lm, i.e., Lm = α × (ΔI / 2) / k. Finally, it compares the target adjustment stroke Lm with the upper limit of the single-step stroke and takes the smaller value as the single-step stroke increment Δs. The control module controls the hydraulic cylinder 8 of the target material distribution device to advance by the single-step stroke increment Δs, and the material distribution plate 9 moves accordingly, reducing the feed amount on the high-current side and thinning the material layer, thereby reducing the current of the high-current side drive motor.

[0033] While controlling the hydraulic cylinder 8 of the target material distribution device to move forward, the control module judges the current stroke of the hydraulic cylinder 8 of the other material distribution device: if the current stroke of the other hydraulic cylinder 8 is greater than zero, then the other hydraulic cylinder 8 is controlled to retreat by the same single-step stroke increment Δs, so that the feed amount on the other side increases and the material layer thickens, thereby accelerating the balance of the current on both sides under the premise that the total feed amount remains unchanged; if the other hydraulic cylinder 8 is at zero stroke, then the other hydraulic cylinder 8 does not retreat.

[0034] Step 5: After the hydraulic cylinder 8 of the target material distribution device completes the single-step stroke increment Δs and a set stabilization waiting time has elapsed, the control module re-acquires and calculates the current difference ΔI. In this embodiment, the stabilization waiting time is 8s to allow the material layer to redistribute and the current to reach a new steady state. The control module records the change Δi of the drive motor current on the corresponding side of the target material distribution device before and after this compensation, calculates the measured unit stroke current response value of this compensation, i.e., Δi divided by the single-step stroke increment Δs, and uses a first-order inertial filtering method to update the unit stroke current response coefficient k online: the updated k is equal to the previous k multiplied by (1 minus the update weight) plus the measured unit stroke current response value multiplied by the update weight. In this embodiment, the update weight is 0.3, i.e., k new =k old ×(1-0.3)+0.3x. Through online updates, the unit stroke current response coefficient k can be automatically corrected according to working conditions such as roller wear and changes in material characteristics, making subsequent compensation more accurate.

[0035] Step 6: The control module determines whether the updated current difference ΔI is still greater than the current difference threshold ΔI. 设 If it is still greater than ΔI 设This indicates that equilibrium has not yet been reached. Return to step three for the next compensation; repeat this process, with each compensation approaching the equilibrium point in a finite step size, until the current difference ΔI is no greater than ΔI. 设 If not greater than ΔI 设 If the compensation is complete, return to step one and the equipment will operate normally.

[0036] Step 7: The control module acquires the current stroke of both hydraulic cylinders 8, calculates the sum of the current strokes of both hydraulic cylinders 8, and calculates the attenuation rate of the unit stroke current response coefficient k relative to its initial value k0. The attenuation rate is equal to (k0 minus the current k) divided by k0. When the sum of the current strokes of both hydraulic cylinders 8 is greater than the preset stroke and threshold, and the attenuation rate of the unit stroke current response coefficient k is greater than the preset attenuation rate threshold, the control module outputs a roller skin replacement prompt signal. In this embodiment, the stroke and threshold are 300mm, and the attenuation rate threshold is 0.3. When the roller skin is severely worn, on the one hand, a larger material distribution stroke is needed to maintain balance, increasing the sum of the strokes on both sides; on the other hand, the current adjustment capability generated per unit stroke decreases, significantly reducing k and increasing the attenuation rate. The roller skin replacement is only prompted when both of the above conditions are met simultaneously. Compared with judging solely by the absolute value of the stroke on one side, this can more realistically reflect the overall wear state of the roller skin and avoid misjudgment caused by temporary fluctuations in the feeding conditions.

[0037] The following is a specific compensation example. The high-pressure roller mill in this embodiment is driven by two 200kW dual motors with a rated current of 360A and a preset current difference threshold ΔI. 设 =30A, dead zone upper limit is 25A, single stroke upper limit is 20mm, stroke and threshold are 300mm, unit stroke current response coefficient initial value k0=0.67A / mm, initially both hydraulic cylinders 8 are at zero stroke.

[0038] During operation, the frequency converter detects the first current I1 and the second current I2 respectively. The control module obtains the first average current I after a 2-second sliding average. 1a =320A, second average current I 2a =280A, calculate the current difference ΔI = |320 - 280| = 40A. Since ΔI = 40A, it is greater than ΔI. 设 (30A) and the duration reaches the 5s confirmation time, indicating an imbalance of current on both sides. Comparison shows that I 1a Greater than I 2aThe current on one side of the moving roller 2 is higher, so the first material distribution device is identified as the target material distribution device. The current difference ΔI = 40A falls within the range of greater than 25A and not greater than 50A, corresponding to a compensation ratio coefficient α = 0.5. The theoretical current adjustment amount is ΔI / 2 = 20A, and the theoretical stroke is 20 ÷ 0.67 ≈ 29.9mm. The target adjustment stroke L_target = 0.5 × 29.9 is approximately 14.9mm, which is less than the upper limit of the single-step stroke of 20mm. Therefore, the single-step stroke increment Δs is taken as 14.9mm. Since the hydraulic cylinder 8 of the second material distribution device is at zero stroke, the hydraulic cylinder 8 of the second material distribution device does not retract, and only the hydraulic cylinder 8 of the first material distribution device advances 14.9mm. After an 8-second stabilization period, the control module re-acquired the current and measured a current drop of approximately 10A on the side corresponding to the first current. The measured unit stroke current response value was approximately 10 ÷ 14.9 ≈ 0.67 A / mm. Based on this, a first-order inertial update was performed on k, resulting in k ≈ 0.67 × 0.7 + 0.67 × 0.3 = 0.67 A / mm. At this point, the current difference ΔI was approximately 20A, not greater than ΔI. 设 The compensation is now complete. The control module obtains that the sum of the current strokes of the two hydraulic cylinders 8 is 14.9mm, which is much less than the stroke and threshold of 300mm. Therefore, no roller skin replacement prompt signal is output, and the equipment is operating normally.

[0039] As the equipment operates for a long time and the rollers gradually wear down, the required material distribution stroke to achieve balance gradually increases, and the current response coefficient k per unit stroke gradually decreases. When the sum of the current strokes of the two hydraulic cylinders 8 is greater than 300mm at a certain moment, and the current response coefficient k per unit stroke decreases from the initial value of 0.67A / mm to below 0.45A / mm, that is, the attenuation rate is greater than 0.3, the control module outputs a roller replacement prompt signal to remind the rollers to be replaced in time.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for automatic compensation control of the current of the moving and stationary rollers in a high-pressure roller mill, wherein the moving roller and stationary roller of the high-pressure roller mill are driven by a moving roller drive motor and a stationary roller drive motor, respectively, and each of the moving roller drive motor and stationary roller drive motor is equipped with a frequency converter. The frequency converter detects the current of the corresponding drive motor in real time. A material distribution device is provided on both sides of the feed hopper of the high-pressure roller mill. The material distribution device includes a hydraulic cylinder, a material distribution plate, and a displacement sensor. The hydraulic cylinder is connected to the material distribution plate through a connecting seat and drives the material distribution plate to reciprocate to change the feed distribution on the corresponding side. The displacement sensor detects the current stroke of the hydraulic cylinder on the corresponding side. The method is characterized in that... Control methods include: Step 1: The first current of the moving roller drive motor and the second current of the stationary roller drive motor are collected in real time by the frequency converter. The control module performs sliding average on the first current and the second current within the set filtering time window to obtain the first average current and the second average current. Step two, the control module calculates the current difference ΔI between the first average current and the second average current. When the current difference ΔI is greater than the preset current difference threshold ΔI... 设 If the duration reaches the set confirmation time, it is determined that the current on both sides is unbalanced and proceeds to step three; otherwise, it returns to step one. Step 3: The control module determines the high current side based on the magnitude of the first average current and the second average current, and identifies the material distribution device corresponding to the high current side as the target material distribution device. Step 4: The control module determines the target adjustment stroke for this compensation based on the current current difference ΔI and the current unit stroke current response coefficient k, and classifies and limits the target adjustment stroke to obtain the single-step stroke increment Δs. The hydraulic cylinder of the target material distribution device is controlled to move forward by the single-step stroke increment Δs to reduce the current of the high-current side drive motor. The unit stroke current response coefficient k is the change in the current of the corresponding side drive motor caused by each unit stroke forward by the hydraulic cylinder. Step 5: After the hydraulic cylinder completes the single-step stroke increment Δs and the set stabilization waiting time has elapsed, the control module recalculates the current difference ΔI and updates the unit stroke current response coefficient k online based on the actual current change caused by the single-step stroke increment Δs. Step 6: Determine whether the updated current difference ΔI is still greater than the current difference threshold ΔI. 设 If yes, return to step three; otherwise, the compensation is complete and return to step one. Step 7: The control module obtains the current stroke of the hydraulic cylinders on both sides. When the sum of the current strokes of the hydraulic cylinders on both sides is greater than the preset stroke and threshold, and the attenuation rate of the unit stroke current response coefficient k relative to its initial value is greater than the preset attenuation rate threshold, the control module outputs a roller skin replacement prompt signal.

2. The automatic compensation control method for the moving and stationary roll current of a high-pressure roller mill according to claim 1, characterized in that, In step one, the moving average is the arithmetic mean of the current sample values ​​collected within the filtering time window, with the duration of the filtering time window ranging from 1 second to 5 seconds.

3. The automatic compensation control method for the moving and stationary roll current of a high-pressure roller mill according to claim 1, characterized in that, In step two, the confirmation time is set between 3 and 10 seconds. When the current difference ΔI is greater than the current difference threshold ΔI... 设 If the duration of the state does not reach the confirmation time, the control module will not trigger compensation.

4. The automatic compensation control method for the moving and stationary roll current of a high-pressure roller mill according to claim 1, characterized in that, After step three, while controlling the hydraulic cylinder of the target material distribution device to move forward in step four, the control module judges the current stroke of the hydraulic cylinder of the other material distribution device. If the current stroke of the hydraulic cylinder of the other material distribution device is greater than zero, the control module controls the hydraulic cylinder of the other material distribution device to move backward by the same single-step stroke increment Δs. If the hydraulic cylinder of the other material distribution device is at zero stroke, the hydraulic cylinder of the other material distribution device does not move backward.

5. The automatic compensation control method for the moving and stationary roll current of a high-pressure roller mill according to claim 1, characterized in that, Step four involves classifying and limiting the target adjustment stroke in single steps, including setting a dead zone, several current difference intervals, and a compensation ratio coefficient corresponding to each interval. The compensation ratio coefficient increases as the current difference interval increases. When the current difference ΔI falls within the dead zone, the single-step stroke increment Δs is zero. When the current difference ΔI is greater than the upper limit of the dead zone, the corresponding compensation ratio coefficient α is selected according to the interval where the current difference ΔI is located. The target adjustment stroke is calculated, and the target adjustment stroke is compared with the preset upper limit of the single-step stroke. The smaller value between the two is taken as the single-step stroke increment Δs.

6. The automatic compensation control method for the moving and stationary roll current of a high-pressure roller mill according to claim 5, characterized in that, The target adjustment stroke L is calculated using the following formula: L = α × (ΔI / 2) / k, where α is the compensation proportional coefficient, ΔI is the current difference, and k is the unit stroke current response coefficient.

7. The automatic compensation control method for the moving and stationary roll current of a high-pressure roller mill according to claim 5, characterized in that, The upper limit of the dead zone is no greater than the current difference threshold ΔI. 设 The maximum single-step travel distance is set at 5mm to 30mm.

8. The automatic compensation control method for the moving and stationary roll current of a high-pressure roller mill according to claim 1, characterized in that, In step five, the online update of the unit stroke current response coefficient k includes: recording the change Δi of the current of the drive motor on the corresponding side of the target material distribution device before and after the compensation, calculating Δi divided by the single-step stroke increment Δs to obtain the measured unit stroke current response value, and weighting the measured unit stroke current response value with the unit stroke current response coefficient k before the update according to the set update weight to obtain the updated unit stroke current response coefficient k.

9. The automatic compensation control method for the moving and stationary roll current of a high-pressure roller mill according to claim 1, characterized in that, In step seven, the attenuation rate is equal to the difference between the initial value k0 of the unit stroke current response coefficient and the current unit stroke current response coefficient k, and then divided by the initial value k0.

10. The automatic compensation control method for the moving and stationary roll current of a high-pressure roller mill according to claim 1, characterized in that, The connecting seat is threadedly connected to the hydraulic cylinder, which is mounted on the upper side of the feed hopper by screws. The material distribution plate is placed between the roller and the slide groove, and the displacement sensor is set on the parallel side of the hydraulic cylinder and connected to the material distribution plate.

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