High-temperature molten salt spherical tank leg servo system and control method thereof

Abstract

The application discloses a high-temperature molten salt spherical tank support leg servo system and a control method thereof, relates to the technical field of high-temperature molten salt energy storage equipment, and comprises a servo hydraulic execution unit, a laser plummet measurement unit and a displacement constraint unit. The laser plummet measurement unit is used for detecting the perpendicularity of each layer of support legs in real time and calculating an offset. The displacement constraint unit is used for presetting the displacement constraint boundary of each layer of support legs. The servo hydraulic execution unit is used for calculating a radial compensation displacement according to the offset and the support leg geometric parameters, driving the corresponding support leg to move along the radial direction synchronously according to the radial compensation displacement and the displacement constraint boundary, and keeping the support leg in a vertical state. The application can realize the active synchronous movement of the support leg along the radial direction during the heating and cooling processes, keep the support leg in a vertical state at all times, effectively release thermal strain, and avoid the self-locking effect of the shell and the support leg from causing the failure of the spherical shell.

Description

Technical Field

[0001] This application relates to the field of high-temperature molten salt energy storage equipment technology, and in particular to a servo system for the legs of a high-temperature molten salt spherical tank and its control method. Background Technology

[0002] Large molten salt energy storage systems (including solar thermal power generation and thermal power plant flexibility retrofit scenarios) typically employ a dual-tank configuration, with the high-temperature tank operating at approximately 290~565℃ and the low-temperature tank operating at approximately 290℃. To address the high risk of weld leakage, inability to completely drain molten salt from the bottom, and difficulties in maintenance associated with existing vertical cylindrical tanks, replacing vertical tanks with spherical tanks (spherical tanks) is an important technological approach. Compared to vertical tanks, spherical tanks offer advantages such as uniform structural stress, uniform thermal expansion, complete molten salt drainage, and simpler civil engineering foundations.

[0003] The spherical bottom of the spherical tank cannot be directly supported on the ground, so a multi-layered space frame support structure is required. The multi-layered space frame support structure is usually composed of multiple concentric columns, V-shaped / X-shaped tie rod assemblies between the columns, and radial reinforcing ribs, which can effectively share the vertical heavy load of the high-temperature molten salt.

[0004] However, in actual operation, the molten salt spherical tank undergoes a heating process (from ambient temperature to approximately 565°C) and a cooling process. During the heating phase, the spherical shell undergoes significant thermal expansion (the expansion in the diameter direction can reach tens of millimeters), while during the cooling phase, the spherical shell contracts. During the thermal expansion, the upper ends of the outriggers move radially outward with the spherical shell, but the lower ends of the outriggers are constrained by ground friction and the tie rod assembly, resulting in asynchronous vertical displacement and causing the outriggers to tilt. After the outriggers tilt, the thermal expansion displacement is transmitted upward to the connection area between the outriggers and the spherical shell, creating a self-locking effect between the shell and the outriggers. This prevents the effective release of thermal strain and seriously affects structural safety.

[0005] The design and manufacturing technology of high-temperature molten salt spherical tanks is a new technology under research, and there is currently no proposed scheme for active servo control of the radial displacement of the outriggers during the operation of the molten salt spherical tank. Summary of the Invention

[0006] The purpose of this application is to provide a servo system for the support legs of a high-temperature molten salt spherical tank and its control method, which can realize the active synchronous movement of the support legs in the radial direction during the heating and cooling process, keep the support legs in a vertical state, effectively release thermal strain, and avoid the self-locking effect between the shell and the support legs that could lead to shell failure.

[0007] To achieve the above objectives, this application provides the following solution: In one aspect, this application provides a servo system for the legs of a high-temperature molten salt spherical tank, which includes: a servo hydraulic actuator, a laser plumb bob measurement unit, and a displacement constraint unit.

[0008] The laser plumb bob measurement unit is used to detect the verticality of each support leg in real time and calculate the offset. The displacement constraint unit is used to preset the displacement constraint boundaries of each layer of support legs.

[0009] The servo hydraulic actuator is used to calculate the radial compensation displacement based on the offset and the outrigger geometric parameters; and drive the corresponding outrigger to move synchronously in the radial direction based on the radial compensation displacement and the displacement constraint boundary, so that the outrigger remains in a vertical state.

[0010] Optionally, the servo hydraulic actuator includes: a hydraulic pump station, a servo system controller, a servo system valve group, a number of hydraulic cylinders corresponding to each layer of outriggers, and displacement sensors.

[0011] The hydraulic pump station is connected to each hydraulic cylinder and is used to provide power to each hydraulic cylinder.

[0012] The hydraulic cylinder is arranged horizontally, with one end connected to the lower part of the outrigger and the other end connected to the foundation or an adjacent fixed reference structure.

[0013] The displacement sensor is used to detect the radial displacement of the corresponding outrigger in real time.

[0014] The servo system controller is used to calculate the radial compensation displacement based on the offset and the outrigger geometry parameters; and to generate control commands based on the radial compensation displacement and the displacement constraint boundary.

[0015] The servo system valve group is connected to the servo system controller and is used to uniformly control the hydraulic cylinders on the same floor according to the control command, and synchronously drive all the outriggers on the same floor to move radially outward or inward.

[0016] Optionally, the bottom of the outrigger is provided with a radial sliding track to cooperate with the corresponding hydraulic cylinder to achieve smooth radial movement of the outrigger.

[0017] Optionally, the laser plumb bob measuring unit has several laser measuring points evenly arranged along the circumference of each support leg. Each measuring point includes a steel pipe perpendicular to the ground, and an upper laser sensor and a lower laser sensor respectively fixed to the upper and lower ends of the steel pipe.

[0018] The axis of the steel pipe is parallel to the centerline of the outrigger when it is perpendicular to the outrigger.

[0019] Optionally, the displacement constraint unit calculates the radial expansion of the spherical shell and the required radial displacement range of the corresponding leg layer under different temperature conditions using a thermo-mechanical coupled finite element model of the high-temperature molten salt spherical tank and its leg structure. The radial displacement range is then converted into the displacement constraint boundary of each leg layer after considering the safety factor. The displacement constraint boundary is preset in the servo system controller as the upper and lower limits of the hydraulic cylinder stroke.

[0020] Optionally, the system further includes an early warning module, used to issue an early warning signal when the radial compensation displacement exceeds the displacement constraint boundary.

[0021] Secondly, this application provides a control method for a high-temperature molten salt spherical tank support leg servo system. The control method is implemented based on the aforementioned high-temperature molten salt spherical tank support leg servo system, and includes: The displacement constraint boundary is preset into the servo system controller.

[0022] Record the initial distance difference between the upper and lower laser sensors at each measuring point on each leg of each layer, and set it as the zero-point reference.

[0023] The distance data between the upper and lower laser sensors at each measurement point of each support leg on each floor is collected in real time, and the offset is calculated.

[0024] Determine whether the offset of each measurement point exceeds a preset threshold to obtain the first judgment result.

[0025] If the first judgment result is negative, then return to the step of "real-time acquisition of distance data between the upper and lower laser sensors of each measuring point of each support leg and calculation of the offset".

[0026] If the first judgment result is yes, then the radial compensation displacement is calculated based on the offset and the outrigger geometric parameters.

[0027] Determine whether the radial compensation displacement exceeds the displacement constraint boundary to obtain a second determination result.

[0028] If the second judgment result is yes, then based on the displacement constraint boundary, drive all hydraulic cylinders of the corresponding outrigger layer to move synchronously, move the outrigger radially outward or inward, and return to the step of "real-time acquisition of distance data between the upper and lower laser sensors of each measuring point of each outrigger layer and calculation of the offset".

[0029] If the second judgment result is negative, then based on the radial compensation displacement, drive all hydraulic cylinders of the corresponding outrigger layer to move synchronously, move the outrigger radially outward or inward, and return to the step of "real-time acquisition of distance data between the upper and lower laser sensors of each measuring point of each outrigger layer and calculation of the offset".

[0030] According to the specific embodiments provided in this application, this application has the following technical effects: This application provides a servo system and control method for the outriggers of a high-temperature molten salt spherical tank. The system includes a servo hydraulic actuator, a laser plumb bob measurement unit, and a displacement constraint unit. The laser plumb bob measurement unit, by real-time detection of the verticality of each outrigger layer and precise calculation of the offset, can dynamically monitor the deformation and offset state of the outriggers throughout the entire process. This avoids the problems of lag, low accuracy, and numerous blind spots associated with traditional manual detection, providing real-time, accurate, and reliable data support for outrigger posture control, ensuring that subsequent control operations are based on evidence and are precisely controllable. The displacement constraint unit, by pre-setting displacement constraint boundaries for each outrigger layer, can define a safe and controllable range for the displacement deformation of the spherical tank outriggers. This effectively avoids structural stress concentration and force imbalance caused by excessive outrigger offset and deformation exceeding limits under high-temperature conditions, thus establishing a solid safety baseline for the operation of the spherical tank outriggers from the source and preventing equipment damage hazards caused by excessive displacement. The servo hydraulic actuator, combined with real-time offset and displacement constraint boundaries, drives the corresponding outriggers to move radially synchronously and maintain a vertical state. This enables real-time correction, dynamic fine-tuning, and synchronous control of outrigger offset errors, ensuring uniform posture and force distribution across multiple outrigger layers. It effectively adapts to the complex operating conditions of high-temperature molten salt spherical tanks under long-term high temperatures and fluctuating loads, continuously maintaining stable outrigger support. This system achieves fully automated closed-loop control of the entire process, including real-time monitoring of tank outrigger verticality, displacement safety management, and dynamic posture correction. This significantly improves the operational stability, control accuracy, and safety reliability of the high-temperature molten salt spherical tank outrigger support system. It effectively solves the industry pain points of easy displacement, deformation, and uneven force distribution of tank outriggers under high-temperature conditions, extending the service life of the tank and outrigger structure, and ensuring the long-term safe, stable, and efficient operation of high-temperature molten salt energy storage equipment. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 A system block diagram of a high-temperature molten salt spherical tank support leg servo system provided in one embodiment of this application; Figure 2 A flowchart illustrating a control method for a high-temperature molten salt spherical tank support leg servo system provided in an embodiment of this application; Figure 3 This is a flowchart illustrating another control method for a high-temperature molten salt spherical tank support leg servo system provided in an embodiment of this application. Detailed Implementation

[0033] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] Molten salt energy storage, as a key supporting technology for the flexible retrofitting of solar thermal power generation and thermal power plants, has entered a window of opportunity for large-scale development. Currently, commercially operating molten salt energy storage systems both domestically and internationally all use vertical cylindrical storage tanks, but these systems suffer from problems such as high risk of weld leakage, inability to drain molten salt from the bottom, difficult maintenance, and huge potential losses in the event of an accident.

[0035] Using spherical storage tanks is a feasible technical approach to solve the above problems. However, the spherical bottom of the tank must be supported by a leg structure. Molten salt spherical tanks undergo significant temperature cycles during operation (the temperature difference during the heating phase can reach about 500°C, and the temperature difference during operation is more than 200°C). The large thermal expansion of the spherical shell is transmitted downward through the upper end of the legs, resulting in asynchronous vertical displacement of the legs, causing tilting and self-locking effects.

[0036] Currently, there are three main types of solutions for dealing with the thermal expansion of spherical tank support legs: First, temporary measures during the construction phase, involving manual observation of the scale plate and manual operation of the linear movement unit to adjust the column position during the tank's heat treatment, which cannot be used in operational conditions; second, adjustments through adjustable tie rod assemblies, which monitor tie rod stress rather than the leg's posture, and are mechanical rather than servo-driven; and third, energy dissipation through passive components such as dampers, which cannot actively control displacement. Furthermore, while multi-layered grid support structures can improve load-bearing capacity, no proactive solution has yet been proposed for the tilting problem caused by the difference in displacement between the upper and lower ends. Additionally, existing spherical tanks have not been used in molten salt applications exceeding 550°C, and traditional technical solutions cannot meet the thermal expansion release requirements at this temperature.

[0037] This application starts from the following idea: Since the fundamental reason for the tilting of the outriggers is that the upper end moves with the spherical shell, while the lower end lags due to friction and the constraint of the tie rod, combined with the self-locking effect caused by thermal expansion, resulting in inconsistent deformation of the outriggers, the displacement difference between the upper and lower parts can be eliminated by actively driving the lower part of the outriggers to move synchronously with the upper part. Based on this idea, a servo hydraulic system is proposed to be introduced into the multi-layer space frame outrigger structure. The difference between the laser plumb bob dual sensor values ​​is used as a direct means of measuring verticality, and the finite element analysis results are used as the displacement constraint boundary to construct a closed-loop control system. During the heating and cooling processes, the lower part of the outriggers is continuously and actively driven to move synchronously in the radial direction, keeping the outriggers in a vertical state at all times.

[0038] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Example 1: In one exemplary embodiment, a high-temperature molten salt spherical tank support leg servo system is provided, the system comprising: a servo hydraulic actuator, a laser plumb bob measurement unit, and a displacement constraint unit.

[0040] The laser plumb bob measurement unit is used to detect the verticality of each support leg in real time and calculate the offset.

[0041] The displacement constraint unit is used to preset the displacement constraint boundaries of each layer of support legs.

[0042] The servo hydraulic actuator is used to calculate the radial compensation displacement based on the offset and the outrigger geometric parameters; and drive the corresponding outrigger to move synchronously in the radial direction based on the radial compensation displacement and the displacement constraint boundary, so that the outrigger remains in a vertical state.

[0043] This system is used to actively drive the outriggers to move synchronously in the radial direction during the heating and cooling process of the molten salt spherical tank, keep the outriggers vertical, release the thermal strain generated by the thin-walled spherical shell plate under high temperature difference conditions, and prevent local stress concentration failure at the connection parts.

[0044] As an optional implementation, the servo hydraulic actuator includes: a hydraulic pump station, a servo system controller, a servo system valve group, a number of hydraulic cylinders corresponding to the number of outriggers on each floor, and displacement sensors.

[0045] The hydraulic pump station is connected to each hydraulic cylinder and is used to provide power to each hydraulic cylinder.

[0046] The hydraulic cylinder is arranged horizontally, with one end connected to the lower part of the outrigger and the other end connected to the foundation or an adjacent fixed reference structure.

[0047] The displacement sensor is used to detect the radial displacement of the corresponding outrigger in real time.

[0048] The servo system controller is used to calculate the radial compensation displacement based on the offset and the outrigger geometry parameters; and to generate control commands based on the radial compensation displacement and the displacement constraint boundary.

[0049] The servo system valve group is connected to the servo system controller and is used to uniformly control the hydraulic cylinders on the same floor according to the control command, and synchronously drive all the outriggers on the same floor to move radially outward or inward.

[0050] Specifically, each outrigger layer is treated as a concentric circular unit, connected to the same servo hydraulic system. The servo hydraulic system includes a hydraulic pump station, a servo system controller, a servo system valve assembly, a corresponding number of hydraulic cylinders for each outrigger layer, and displacement sensors. The hydraulic cylinders are horizontally arranged, with one end connected to the lower part of the outrigger (near the base plate) and equipped with a radial outrigger sliding track to coordinate with the corresponding hydraulic cylinder for smooth radial movement of the outrigger; the other end connects to the foundation or an adjacent fixed reference structure. The hydraulic cylinders of each outrigger layer are uniformly controlled through the servo system valve assembly, synchronously driving all outriggers in that layer to move radially outward or inward. The stroke range of the hydraulic cylinders is preset by the displacement constraint unit, while the movement rate is determined based on the results of the laser plumb bob measurement unit.

[0051] As an optional implementation, the laser plumb bob measuring unit has several laser measuring points evenly arranged along the circumference of each support leg. Each measuring point includes a steel pipe perpendicular to the ground, and an upper laser sensor and a lower laser sensor respectively fixed to the upper and lower ends of the steel pipe.

[0052] The axis of the steel pipe is parallel to the centerline of the outrigger when it is perpendicular to the outrigger.

[0053] Specifically, 3-4 laser measurement points are evenly arranged along the circumference of each leg. Each measurement point has a laser sensor installed at both the upper and lower ends of the leg. The upper and lower sensors are mounted on a steel pipe perpendicular to the ground, using a rigid connection structure to ensure a fixed relative position. The upper and lower laser sensors are fixed to both ends of the steel pipe, and the axis of the steel pipe is parallel to the designed axis of the leg (i.e., the centerline of the leg in its vertical position).

[0054] Measurement Principle: In the initial installation state (legs vertical), the upper and lower laser sensors measure their distances from a reference surface (which can be the outer surface of the spherical shell or an independently set reference structure), and the difference between the two is set as the zero-point reference. When the outrigger tilts due to thermal expansion thrust, the distance changes measured by the upper and lower sensors are different, and the difference Δd reflects the direction and amount of the outrigger's offset. When Δd exceeds a preset threshold, the servo system is triggered to perform radial displacement compensation.

[0055] As an optional implementation, the displacement constraint unit calculates the radial expansion of the spherical shell and the required radial displacement range of the corresponding leg layer under different temperature conditions using a thermo-mechanical coupled finite element model of the high-temperature molten salt spherical tank and its leg structure. The radial displacement range is then converted into the displacement constraint boundary of each leg layer after considering the safety factor. The displacement constraint boundary is preset in the servo system controller as the upper and lower limits of the hydraulic cylinder stroke.

[0056] Specifically, during the design phase, a thermo-mechanical coupled finite element model of the high-temperature molten salt spherical tank and its support structure is established. The radial expansion of the spherical shell and the required radial displacement range for the corresponding support layers are calculated under different temperature conditions (segmented temperature points during the heating and cooling stages). The calculation results, after considering a safety factor, are converted into displacement constraint boundaries for each support layer (including the maximum allowable displacement and the displacement-temperature correspondence), and preset into the servo system controller as the upper and lower limits of the hydraulic cylinder stroke. During operation, the actual drive displacement of the servo system controller does not exceed these constraint boundaries, ensuring that the support movement always remains within the designed safe range.

[0057] As an optional implementation, the system further includes: The early warning module is used to issue an early warning signal when the radial compensation displacement exceeds the displacement constraint boundary.

[0058] System block diagram as follows Figure 1 As shown, the system achieves active synchronous radial movement of the outriggers during heating and cooling through a three-in-one closed-loop control of "displacement constraint boundary + laser plumb bob measurement feedback + servo hydraulic actuation". This keeps the outriggers in a vertical position, effectively releases thermal strain, and avoids the self-locking effect between the shell and the outriggers, which could lead to shell failure.

[0059] Example 2: In one exemplary embodiment, such as Figure 2 As shown, a control method for a high-temperature molten salt spherical tank support leg servo system is provided. The control method is based on the aforementioned high-temperature molten salt spherical tank support leg servo system and includes: S1: Preset the displacement constraint boundary into the servo system controller.

[0060] S2: Record the initial distance difference between the upper and lower laser sensors at each measurement point of each support leg, and set it as the zero-point reference.

[0061] S3: Real-time acquisition of distance data between the upper and lower laser sensors at each measurement point of each support leg, and calculation of the offset.

[0062] S4: Determine whether the offset of each measurement point exceeds the preset threshold, and obtain the first judgment result.

[0063] If the first judgment result is negative, then return to the step of "real-time acquisition of distance data between the upper and lower laser sensors of each measuring point of each support leg and calculation of the offset".

[0064] If the first judgment result is yes, then the radial compensation displacement is calculated based on the offset and the outrigger geometric parameters.

[0065] S5: Determine whether the radial compensation displacement exceeds the displacement constraint boundary to obtain a second determination result.

[0066] If the second judgment result is yes, then based on the displacement constraint boundary, drive all hydraulic cylinders of the corresponding outrigger layer to move synchronously, move the outrigger radially outward or inward, and return to the step of "real-time acquisition of distance data between the upper and lower laser sensors of each measuring point of each outrigger layer and calculation of the offset".

[0067] If the second judgment result is negative, then based on the radial compensation displacement, drive all hydraulic cylinders of the corresponding outrigger layer to move synchronously, move the outrigger radially outward or inward, and return to the step of "real-time acquisition of distance data between the upper and lower laser sensors of each measuring point of each outrigger layer and calculation of the offset".

[0068] As an optional implementation, a warning signal is issued when the radial compensation displacement exceeds the displacement constraint boundary.

[0069] As an optional implementation, the hydraulic cylinder drives the outrigger to move radially outward under heating conditions, and the hydraulic cylinder drives the outrigger to move radially inward under cooling conditions.

[0070] Example 3: In practical applications, such as Figure 3 As shown, the control method includes the following steps: S1 (Preset Stage): During the design stage, the radial displacement range required for each layer of the support leg under different temperature conditions is obtained through finite element analysis, and the displacement constraint boundary (including the maximum allowable displacement and the displacement-temperature correspondence table) is preset into the servo system controller.

[0071] S2 (Initialization Phase): After the initial system installation is completed, record the initial distance difference between the upper and lower laser sensors at each measurement point of each support leg and set it as the zero point reference.

[0072] S3 (Real-time Monitoring Stage): During the heating or cooling process of the molten salt spherical tank, the laser plumb bob measurement unit collects the distance data between the upper and lower sensors at each measurement point of each support leg in real time and calculates the offset Δd.

[0073] S4 (Judgment Phase): The servo system controller compares the Δd of each measurement point with a preset threshold. If |Δd| of any measurement point exceeds the threshold, proceed to S5; otherwise, return to S3 to continue monitoring.

[0074] S5 (Displacement Calculation Stage): The servo system controller determines the offset direction based on the sign of Δd, calculates the required radial compensation displacement of the lower part of the support leg based on the amplitude of Δd and the geometric parameters of the support leg, and checks the radial compensation displacement against the finite element displacement constraint boundary. If the radial compensation displacement exceeds the displacement constraint boundary, the displacement constraint boundary value is used as the actual driving amount.

[0075] S6 (Execution Phase): The servo system controller outputs a control signal to the servo system valve group, driving all hydraulic cylinders of the corresponding outrigger layer to move synchronously, moving the lower part of the outrigger radially outward (heating condition) or inward (cooling condition) until |Δd| of all measurement points in that layer returns to the threshold range.

[0076] S7 (Loop): Return to S3 for continuous monitoring and closed-loop correction.

[0077] This method obtains the radial displacement determined by the finite element analysis during the design phase as the moving boundary constraint; during the heating and cooling process, the verticality deviation of each leg is obtained in real time through the laser plumb bob measurement unit; when the deviation exceeds the preset threshold, the servo hydraulic unit drives the leg of the corresponding leg layer to move synchronously outward or inward along the radial direction until the verticality is restored to the allowable range.

[0078] Compared to existing technologies, the advantages of this application are as follows: (1) Upgrade the thermal deformation management of the outriggers from “passive adaptation” to “active servo control”.

[0079] Existing technologies cannot provide active and continuous control of the outrigger posture during the operation of high-temperature spherical tanks. This application introduces a servo hydraulic system into the outrigger structure of a molten salt spherical tank for the first time, realizing active driving and closed-loop control of the outrigger radial displacement, fundamentally solving the problem of outrigger thermal expansion self-locking.

[0080] (2) The verticality of the outriggers is used as the direct control target, and the control logic is clear and reliable.

[0081] This application uses the difference between the upper and lower dual sensors of the laser plumb bob as a direct measurement method to directly reflect the tilt of the outrigger (i.e., the control target itself), avoiding the cumulative error of indirect measurement and achieving higher control accuracy.

[0082] (3) Displacement constraint boundary ensures operational safety.

[0083] The results of the thermo-mechanical coupling finite element analysis in the design phase are solidified as the upper limit of displacement constraints to ensure that the motion range of the servo system is always within the safe range of the design verification, thus avoiding structural risks caused by over-driving.

[0084] (4) Each support leg is independently controlled to adapt to the uneven expansion of the spherical shell.

[0085] Each support leg is equipped with an independent hydraulic cylinder group and laser measurement point. The controller can calculate the compensation amount and drive the execution according to the offset state of each support leg, adapting to the interlayer differences in the radial expansion of the spherical shell at different temperature stages.

[0086] (5) Reduce the risk of structural damage and extend the service life of equipment.

[0087] By actively releasing thermal strain, the self-locking effect and local stress concentration caused by outrigger tilting can be avoided, which can reduce the risk of fatigue damage in the outrigger-shell connection area and extend the overall service life of the molten salt spherical tank.

[0088] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A servo system for the legs of a high-temperature molten salt spherical tank, characterized in that, The system includes: a servo hydraulic actuator, a laser plumb bob measurement unit, and a displacement constraint unit; The laser plumb bob measurement unit is used to detect the verticality of each support leg in real time and calculate the offset. The displacement constraint unit is used to preset the displacement constraint boundaries of each layer of support legs; The servo hydraulic actuator is used to calculate the radial compensation displacement based on the offset and the outrigger geometric parameters; and drive the corresponding outrigger to move synchronously in the radial direction based on the radial compensation displacement and the displacement constraint boundary, so that the outrigger remains in a vertical state.

2. The high-temperature molten salt spherical tank support leg servo system according to claim 1, characterized in that, The servo hydraulic actuator includes: a hydraulic pump station, a servo system controller, a servo system valve group, a number of hydraulic cylinders corresponding to each layer of outriggers, and displacement sensors. The hydraulic pump station is connected to each hydraulic cylinder and is used to provide power to each hydraulic cylinder; The hydraulic cylinder is arranged horizontally, with one end connected to the lower part of the outrigger and the other end connected to the foundation or an adjacent fixed reference structure. The displacement sensor is used to detect the radial displacement of the corresponding outrigger in real time. The servo system controller is used to calculate the radial compensation displacement based on the offset and the outrigger geometric parameters; and to generate control commands based on the radial compensation displacement and the displacement constraint boundary. The servo system valve group is connected to the servo system controller and is used to uniformly control the hydraulic cylinders on the same floor according to the control command, and synchronously drive all the outriggers on the same floor to move radially outward or inward.

3. The high-temperature molten salt spherical tank support leg servo system according to claim 1, characterized in that, The bottom of the outrigger is equipped with a radial sliding track, which is used to cooperate with the corresponding hydraulic cylinder to achieve smooth radial movement of the outrigger.

4. The high-temperature molten salt spherical tank support leg servo system according to claim 1, characterized in that, The laser plumb bob measuring unit has several laser measuring points evenly arranged along the circumference of each support leg. Each measuring point includes a steel pipe perpendicular to the ground, and an upper laser sensor and a lower laser sensor respectively fixed to the upper and lower ends of the steel pipe. The axis of the steel pipe is parallel to the centerline of the outrigger when it is perpendicular to the outrigger.

5. The high-temperature molten salt spherical tank support leg servo system according to claim 1, characterized in that, The displacement constraint unit calculates the radial expansion of the spherical shell and the required radial displacement range of the corresponding leg layer under different temperature conditions using a thermo-mechanical coupled finite element model of the high-temperature molten salt spherical tank and its leg structure. After considering the safety factor, the radial displacement range is converted into the displacement constraint boundary of each leg layer. The displacement constraint boundary is preset in the servo system controller as the upper and lower limits of the hydraulic cylinder stroke constraint.

6. The high-temperature molten salt spherical tank support leg servo system according to claim 1, characterized in that, The system also includes: The early warning module is used to issue an early warning signal when the radial compensation displacement exceeds the displacement constraint boundary.

7. A control method for a servo system of a high-temperature molten salt spherical tank support leg, characterized in that, The control method is implemented based on the high-temperature molten salt spherical tank support leg servo system according to any one of claims 1-6, and the control method includes: The displacement constraint boundary is preset into the servo system controller; Record the initial distance difference between the upper and lower laser sensors at each measurement point on each leg of each layer, and set it as the zero-point reference. Real-time data collection of distances between the upper and lower laser sensors at each measurement point of each support leg on each floor, and calculation of the offset; Determine whether the offset of each measurement point exceeds a preset threshold to obtain the first judgment result; If the first judgment result is negative, then return to the step of "real-time acquisition of distance data between the upper and lower laser sensors of each measuring point of each support leg and calculation of the offset"; If the first determination result is yes, then the radial compensation displacement is calculated based on the offset and the outrigger geometric parameters; Determine whether the radial compensation displacement exceeds the displacement constraint boundary to obtain a second determination result; If the second judgment result is yes, then based on the displacement constraint boundary, drive all hydraulic cylinders of the corresponding outrigger layer to move synchronously, move the outrigger radially outward or inward, and return to the step of "real-time acquisition of distance data between the upper and lower laser sensors of each measuring point of each outrigger layer and calculation of the offset". If the second judgment result is negative, then based on the radial compensation displacement, drive all hydraulic cylinders of the corresponding outrigger layer to move synchronously, move the outrigger radially outward or inward, and return to the step of "real-time acquisition of distance data between the upper and lower laser sensors of each measuring point of each outrigger layer and calculation of the offset".

8. The control method for the high-temperature molten salt spherical tank support leg servo system according to claim 7, characterized in that, When the radial compensation displacement exceeds the displacement constraint boundary, a warning signal is issued.

9. The control method for the high-temperature molten salt spherical tank support leg servo system according to claim 7, characterized in that, Under heating conditions, the hydraulic cylinder drives the outrigger to move radially outward; under cooling conditions, the hydraulic cylinder drives the outrigger to move radially inward.

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