A control method for preventing lockout and non-return during photovoltaic push rod brake process

Abstract

This invention belongs to the field of photovoltaic actuator technology and discloses a control method to prevent the photovoltaic actuator from locking up and being unable to retract during braking. The method includes: S1, the central control unit of the photovoltaic support is activated, and the electric actuator operates by calculating solar time to ensure normal tracking and maximize solar energy utilization; S2, the central control unit accurately acquires the real-time operating angle of the photovoltaic support using a dual data fusion mechanism. The central control unit also includes a tilt sensor and a pulse width modulation module, and a Hall sensor is installed in the motor that drives the electric actuator to extend and retract; S3, a buffer warning zone is set in the central control unit to prevent the photovoltaic support from entering a hard limit braking angle. This invention has a simple overall structure and can actively avoid hard limit braking impact and guide the actuator to retract smoothly by optimizing the braking timing, thus improving the performance.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic actuator technology, specifically, it relates to a control method to prevent photovoltaic actuators from locking up and becoming unable to retract during braking. Background Technology

[0002] Photovoltaic tracking brackets are driven by electric push rods to rotate around an axis, enabling real-time tracking of the sun's azimuth angle. This can improve the power generation efficiency of photovoltaic modules by 15%-30%, making it one of the core components of large-scale ground-mounted photovoltaic power plants. A key design feature is the hard limit switch, which ensures the safe operation of the bracket. When the bracket rotates to its limit angle (e.g., azimuth ±45°), the hard limit switch triggers a brake to prevent structural tearing (e.g., column tilting, purlin deformation) or collision with adjacent arrays due to excessive rotation.

[0003] Typically, a hardware locking mechanism is installed at the end of the electric push rod as a hard limit mechanism. However, the push rod (mostly electric push rod) of the photovoltaic tracking bracket cannot retract after reaching the hard limit, which is a common fault in the tracking system. Misalignment of the teeth of the lead screw and nut inside the electric push rod may cause the bracket to jam, the motor to burn out due to overload, or even structural deformation (because the hard limit is mostly a mechanical rigid block).

[0004] A Chinese patent application (CN201610444424.6) discloses a hard-limiting device and control method for achieving self-elimination of operating errors and wind resistance in a solar tracking system. The control method includes: a control unit controlling a drive motor to stop its current tracking operation, reverse its rotation for a certain number of revolutions, and then resume forward operation; simultaneously, the control unit detects the drive motor's operating current I and compares it with Io; when it is determined that the solar tracking system is in a hard-limiting state, the control unit re-acquires the reference angle parameter Ao and clears the errors generated during operation; for increases in the drive motor's operating current caused by external forces, which is considered a wind-resistant state, the control unit controls the drive motor to return to the optimal wind-resistant angle. This method achieves both self-correction of operating errors and wind-resistant state in the solar tracking system without the need for angle and wind speed sensors, and the limiting and error clearing are more accurate and reliable, effectively reducing the system's own cost and saving installation costs.

[0005] However, the hard limit structure in this patent still poses a risk of instantaneous locking during the braking process of the photovoltaic push rod, making it unable to retract. Summary of the Invention

[0006] The main technical problem to be solved by this invention is to provide a control method for photovoltaic push rods that lock up and cannot retract during braking. This method can actively avoid the impact of hard limit braking and guide the push rod to retract smoothly by optimizing the braking sequence, dynamically adjusting the driving force, and linking overload protection and retraction strategies. This reduces the risk of mechanical jamming and power failure from the source, while improving the operational reliability of photovoltaic tracking brackets and reducing operation and maintenance costs.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] A control method for preventing a photovoltaic push rod from locking up and becoming unable to retract during braking includes the following steps:

[0009] S1. The central control unit of the photovoltaic bracket is activated, and the electric push rod operates to perform normal tracking by calculating solar time, ensuring the maximum utilization rate of solar energy;

[0010] S2. The central control unit uses a dual data fusion mechanism to accurately acquire the real-time operating angle of the photovoltaic bracket. The central control unit is also equipped with an tilt sensor and a pulse width modulation module. The motor that drives the electric push rod to extend and retract is equipped with a Hall sensor.

[0011] S3. Set up a buffer warning zone for the operating angle of the photovoltaic support in the central control unit;

[0012] When the real-time high-precision angle value of the photovoltaic support enters the buffer warning zone during operation, the central control unit controls the start of the pulse width modulation module to control the torque output of the electric push rod to enter the torque decay mode until it slowly reaches the hard limit to complete the braking.

[0013] When the high-precision angle value detected by the central control unit during the rotation of the photovoltaic support does not enter the buffer warning zone, the central control unit controls the photovoltaic support to continue normal tracking.

[0014] S4. When the high-precision angle value detected by the central control unit moves away from the buffer warning zone, if the central control unit detects that the electric push rod is still in torque decay mode, it will activate the pulse width modulation module to adjust the motor to switch from torque decay mode to rated torque normal tracking mode for normal tracking.

[0015] If the central control unit detects that the electric actuator is already in the rated torque normal tracking mode, it will continue to track normally and repeat this process.

[0016] The following are further optimizations of the above technical solution by the present invention:

[0017] In step S2, the dual data fusion mechanism includes:

[0018] a1. The operating angle of the photovoltaic bracket, which is collected in real time by the tilt sensor, is taken as the actual angle;

[0019] a2. The Hall sensor can count the rotor speed of the motor and calculate the angle of the photovoltaic bracket as the theoretical operating angle of the photovoltaic bracket by using the motor speed-push rod extension-bracket angle conversion model preset in the central control unit.

[0020] a3. The angle value obtained by weighting the actual angle and the theoretical operating angle is used as the real-time high-precision angle value during the rotation operation of the photovoltaic support.

[0021] Further optimization: In step S3, the buffer warning zone is set to a range of 3-5° from the hard limit.

[0022] Further optimization: The pulse width modulation module can dynamically adjust the power supply frequency of the motor, and the torque attenuation mode is a process in which the output torque of the electric actuator decreases in a stepwise manner from the rated value.

[0023] The present invention, by adopting the above technical solution, has the following beneficial effects:

[0024] This invention employs the aforementioned technical solution, which is ingeniously conceived. By setting a buffer warning zone, when the photovoltaic support enters this zone, the torque of the drive motor driven by the pulse width modulation module decreases in a stepwise manner (the torque decreases by 20% for every 1° approach to the hard limit), ultimately reducing the torque to 30%-50% of the rated value at the hard limit. This gradual deceleration reduces the impact force of the collision by 40%-60%, effectively avoiding "mechanical deadlock" problems such as misalignment of the push rod lead screw and nut teeth, and plastic deformation of the support anchor point, thus reducing the risk of motor overload and burnout.

[0025] The system employs a dual data fusion mechanism combining an tilt sensor and a Hall sensor: the tilt sensor directly acquires the actual angle of the support, while the Hall sensor calculates the theoretical angle using the motor speed. The two sensors are weighted together to generate a high-precision real-time angle value (error ≤ 0.2°). This design ensures the accuracy of buffer warning zone judgment and torque adjustment, avoiding misoperation caused by errors from a single sensor.

[0026] When the photovoltaic support moves away from the buffer warning zone and away from the hard limit, the pulse width modulation module switches from "torque attenuation mode" to "rated torque mode" within 30ms, instantly restoring the motor's rated power. This design solves the problem of jamming caused by insufficient power in the push rod after traditional hard limit braking, reducing the need for manual maintenance intervention and lowering maintenance costs.

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0028] Figure 1 This is a flowchart of a control method for preventing the photovoltaic push rod from locking up and becoming unable to retract during braking, as described in an embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram of the installation structure of the electric actuator on the photovoltaic bracket in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram from another angle showing the installation structure of the electric actuator on the photovoltaic bracket in an embodiment of the present invention.

[0031] In the diagram: 1. Electric actuator; 2. Photovoltaic bracket; 3. Motor; 4. Central control unit; 41. Hall sensor; 42. Tilt sensor; 43. Pulse width modulation module. Detailed Implementation

[0032] like Figure 1-3 As shown: A control method to prevent a photovoltaic push rod from locking up and becoming unable to retract during braking, specifically including the following steps:

[0033] S1, the central control unit 4 of the photovoltaic bracket 2 is started, and the electric push rod 1 runs to perform normal tracking by calculating solar time to ensure the maximum utilization of solar energy;

[0034] In this embodiment, the specific structure of driving the photovoltaic bracket 2 with the electric push rod 1 to track solar energy to maximize the utilization of solar energy is well known in the prior art and will not be described in detail here.

[0035] The central control unit 4 is equipped with a master controller, which realizes the calculation of solar time and drives the electric push rod 1 to complete the tracking. The specific control principle is well known in the prior art and will not be described in detail here.

[0036] S2 and the central control unit 4 use a dual data fusion mechanism to accurately acquire the real-time operating angle of the photovoltaic bracket 2;

[0037] The central control unit 4 is also equipped with a tilt sensor 42 and a pulse width modulation module 43, and the motor 3 that drives the electric push rod 1 to extend and retract is equipped with a Hall sensor 41.

[0038] The dual data fusion mechanism includes:

[0039] a1. The tilt sensor 42 can collect the rotation angle, angular velocity and running direction of the photovoltaic bracket 2 in real time, and the running angle of the photovoltaic bracket 2 collected by the tilt sensor 42 in real time is used as the actual angle.

[0040] a2. The Hall sensor 41 can count the rotor speed of the motor 3 and calculate the angle of the photovoltaic bracket 2 by using the motor 3 speed-push rod extension-bracket angle conversion model preset in the central control unit 4 as the theoretical operating angle of the photovoltaic bracket 2.

[0041] a3. The angle value obtained by weighting the actual angle and the theoretical operating angle is used as the real-time high-precision angle value during the rotation operation of the photovoltaic support 2.

[0042] In this embodiment, as Figure 3 As shown, the conversion model of motor speed 3 - push rod extension / retraction amount - bracket angle is as follows: The photovoltaic tracking bracket formed by the photovoltaic bracket 2 and the electric push rod 1 forms a triangular structure. The column length of the photovoltaic bracket 2 is set as a, the length of the rocker arm rotatably connected to one end of the column is set as b, and the initial length of the electric push rod 1, which is hinged to the other end of the column and the other end of the rocker arm, is set as L1, and the length after extension or retraction is L2. Then the stroke of the electric push rod 1 is ΔL = L2 - L1. At the initial moment, the angle between the column and the electric push rod 1 is set as α1, and the angle between the column and the electric push rod 1 after the change of the electric push rod 1 is set as α2. According to the formula cosα1 = (a 2 +L1 2 -b 2 ) / (2aL1), cosα2=(a 2 +L2 2 -b 2 ) / (2aL2), calculate the tracking angle θ=α2-α1, θ is the theoretical operating angle of photovoltaic bracket 2;

[0043] The stroke ΔL of the electric push rod 1 can be obtained by the Hall sensor 41. The Hall sensor 41 can detect the number of rotations of the rotor of the motor 3 by recording the number of pulses. Then, the stroke ΔL of the electric push rod 1 is calculated by the Hall pulse coefficient of the Hall sensor 41 and the reduction ratio of the electric push rod 1. The specific calculation principle is known in the prior art and will not be described in detail here.

[0044] The weighted operation is a commonly used method in data processing and analysis. It assigns different weights to each data point based on its importance in the whole, and then performs calculations to more reasonably reflect the overall situation of the data. The specific calculation principle is well known and will not be elaborated here.

[0045] S3. Set a buffer warning zone in the central control unit 4 to indicate when the operating angle of the photovoltaic bracket 2 enters the hard limit;

[0046] In this embodiment, the buffer warning zone is set to a range of 3-5° from the hard limit. That is, when the real-time high-precision angle value detected during the rotation of the photovoltaic bracket 2 in step S2 enters the buffer warning zone, the central control unit 4 controls the start of the pulse width modulation module 43 to control the torque output of the electric push rod 1 to enter the torque decay mode until it slowly reaches the hard limit to complete the braking.

[0047] When the high-precision angle value detected by the central control unit 4 during the rotation of the photovoltaic bracket 2 does not enter the buffer warning zone, the central control unit 4 controls the photovoltaic bracket 2 to continue normal tracking.

[0048] In this embodiment, the pulse width modulation module 43 can dynamically adjust the power supply frequency of the motor, and the torque attenuation mode is a process in which the output torque of the electric push rod 1 decreases stepwise from the rated value.

[0049] The torque attenuation mode is a progressive adjustment mechanism that ensures that the photovoltaic bracket 2 gradually decelerates as it approaches the hard limit buffer warning zone (ensuring a 20% reduction in torque for every 1° approach to the hard limit). When it finally reaches the hard limit, the torque output by the electric push rod 1 is reduced to 30%-50% of the rated value, thereby controlling the impact force within the safety threshold. This reduces the impact load by 40%-60% compared to traditional solutions and effectively avoids the hidden dangers of "mechanical deadlock" such as misalignment of the push rod lead screw and nut teeth and plastic deformation of the bracket anchor point.

[0050] The pulse width modulation module 43 dynamically adjusts the power supply frequency of the motor through its built-in SG3525 chip. The specific adjustment principle is well known and will not be described in detail here.

[0051] S4. When the high-precision angle value detected by the central control unit 4 moves from the buffer warning zone to a position away from the buffer warning zone, if the central control unit 4 detects that the operating mode of the electric push rod 1 is still the torque decay mode, the pulse width modulation module 43 is activated to adjust the motor 3 from the torque decay mode to the rated torque normal tracking mode for normal tracking.

[0052] If the central control unit 4 detects that the electric push rod 1 is already in the rated torque normal tracking mode, it will continue to track normally and repeat this process.

[0053] In this embodiment, the pulse width modulation module 43 can complete the conversion from torque attenuation mode to rated torque normal tracking mode within 30ms. By restoring the rated power supply parameters of motor 3, the electric push rod 1 drives the photovoltaic bracket 2 to run with maximum torque, ensuring that the response speed and tracking accuracy of the tracking system in the non-limited area are not affected, and taking into account the balance between hard limit protection and power generation efficiency.

[0054] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A control method for preventing lockout and non-retraction during a photovoltaic push rod brake process, characterized in that: Includes the following steps: ​ S1. The central control unit (4) of the photovoltaic bracket (2) is started, and the electric push rod (1) runs to perform normal tracking by calculating solar time to ensure the maximum utilization rate of solar energy. S2. The central control unit (4) uses a dual data fusion mechanism to accurately obtain the real-time operating angle of the photovoltaic bracket (2). The central control unit (4) is also equipped with an tilt sensor (42) and a pulse width modulation module (43). The motor (3) that drives the electric push rod (1) to extend and retract is equipped with a Hall sensor (41). S3. Set up a buffer warning zone for the operating angle of the photovoltaic bracket (2) in the central control unit (4); When the real-time high-precision angle value of the photovoltaic bracket (2) enters the buffer warning zone during operation, the central control unit (4) controls the start of the pulse width modulation module (43) to control the torque output of the electric push rod (1) to enter the torque decay mode until it slowly reaches the hard limit to complete the braking. When the high-precision angle value detected by the central control unit (4) during the rotation of the photovoltaic bracket (2) does not enter the buffer warning zone, the central control unit (4) controls the photovoltaic bracket (2) to continue normal tracking. S4. When the high-precision angle value detected by the central control unit (4) moves from the buffer warning zone to a position far away from the buffer warning zone, if the central control unit (4) detects that the operating mode of the electric push rod (1) is still the torque decay mode, the pulse width modulation module (43) is activated to adjust the motor (3) to switch from the torque decay mode to the rated torque normal tracking mode for normal tracking. If the central control unit (4) detects that the electric push rod (1) is in the rated torque normal tracking mode, it continues to track normally and repeats this process.

2. The control method for preventing lock-up and non-return during photovoltaic rod brake according to claim 1, characterized in that: In step S2, the dual data fusion mechanism includes: a1. The operating angle of the photovoltaic bracket (2) collected in real time by the tilt sensor (42) is taken as the actual angle; a2. The Hall sensor (41) can count the rotor speed of the motor (3) and calculate the angle of the photovoltaic bracket (2) by using the motor speed-push rod extension-bracket angle conversion model preset in the central control unit (4) as the theoretical operating angle of the photovoltaic bracket (2). a3. The angle value obtained by weighting the actual angle and the theoretical operating angle is used as the real-time high-precision angle value of the photovoltaic bracket (2) during rotation.

3. The control method for preventing lock-up and non-return during photovoltaic rod brake according to claim 1, characterized in that: In step S3, the buffer warning zone is set to a range of 3-5° from the hard limit.

4. The control method for preventing the lock-up from being unable to return during the photovoltaic push rod brake process according to claim 3, characterized in that: The pulse width modulation module (43) can dynamically adjust the power supply frequency of the motor. The torque attenuation mode is the process of the electric push rod (1) output torque attenuating in a stepwise manner from the rated value.

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