CN116594432A - A sensorless control method and device for a photovoltaic power generation light tracking system - Google Patents

Abstract

The invention discloses a sensorless control method and equipment for a photovoltaic power generation light tracking system. The photovoltaic power generation light tracking system is installed in parallel between a solar photovoltaic panel and a biaxial tracking support. The altitude angle and azimuth angle signals of the solar photovoltaic panel calculate the correct steering angle required by the stepper motor, thereby realizing sensorless light tracking control. The sensorless control method proposed by the present invention is based on the analytical relationship between changes in the elevation angle and azimuth angle of the photovoltaic panel and the maximum output power of the internal MPPT, continuously adjusts the elevation angle and azimuth angle, realizes precise light tracking of the photovoltaic panel, and improves the photovoltaic panel. The power generation efficiency reduces the construction cost of the photovoltaic light tracking system, and it has strong versatility and is easy to implement.

Description

A sensorless control method and device for a photovoltaic power generation light tracking system

technical field

The invention belongs to the field of new energy photovoltaics, and in particular relates to a sensorless control method for a photovoltaic power generation light tracking system.

Background technique

With the continuous development of human society and the increasing demand for energy, solar energy, as a green, clean and renewable energy, has received more and more attention and attention. The solar panel is the core component of solar power generation, and the improvement of its efficiency directly determines the power generation and economy of the solar power generation system. However, since the power generation efficiency and output power of solar panels are affected by many factors, such as the sun's altitude angle, azimuth angle, shadow, etc., changes in these factors will lead to a decrease in the power generation efficiency and output power of solar panels. In order to solve this problem, a photovoltaic panel light tracking system was added. By installing a special tracking bracket, the solar panel can automatically rotate and tilt with the movement of the sun to absorb solar energy to the greatest extent. This technology enables solar panels to always face the sun and receive solar radiation to the maximum extent, improving the efficiency of photovoltaic power generation.

There are many defects in the existing light-following control. The open-loop control based on the astronomical algorithm is difficult to achieve the ideal accuracy, and there will be cumulative errors under long-term tracking, which leads to the actual machining and installation errors are often much greater than the algorithm errors; the application of photosensitive sensors, cameras or GPS Although the closed-loop control with external sensors can achieve higher accuracy, the additional determination device will inevitably increase the construction cost in large-area photovoltaic arrays. The impact will greatly reduce its service life. However, there is no sensorless closed-loop control strategy in the current light tracking control technology.

Contents of the invention

The technical problem to be solved by the present invention is to study and propose a sensorless closed-loop control strategy for precise light tracking in view of the defects of open-loop control with large cumulative error and high-cost closed-loop control in existing light-tracking control.

In order to solve the above technical problems, the present invention adopts the following technical solutions:

The invention proposes a sensorless control method for a photovoltaic power generation tracking system. The photovoltaic tracking control system is installed in parallel between the solar photovoltaic panel and the biaxial tracking bracket. The signal and the solar photovoltaic panel altitude angle and azimuth angle signals calculate the correct angle for the photovoltaic panel to turn, so as to realize the sensorless light tracking control of photovoltaic power generation; among them, the steps to establish the sensorless light tracking control strategy of photovoltaic power generation are as follows:

S1. Establish a mathematical model of the angle between the photovoltaic panel and the sun's rays to represent the direct relationship between the photovoltaic panel and the sun's rays;

S2. Establish the height angle of the photovoltaic panel , azimuth /> and maximum output power of photovoltaic modules/> Between the mathematical analytical equations, use the discrete method to calculate the maximum output power curve for the height angle /> and azimuth /> The slope of;

S3. Establish a sensorless tracking light control strategy based on the initial position of the photovoltaic panel to continuously adjust the height angle of the photovoltaic panel and azimuth /> , to meet the minimum angle between the normal line of the photovoltaic panel and the incident light of the sun, so that the output power at the current moment can be kept at the maximum value.

Further, in step S1, the angle between the photovoltaic panel and the horizontal plane is defined as the height angle of the photovoltaic panel , the angle between the projection of the vertical normal of the photovoltaic panel on the horizontal plane and the true south latitude is defined as the orientation angle of the photovoltaic panel /> , the angle between the sun's incident light and the normal of the photovoltaic panel is defined as the sun's incident angle /> ; The OP vector is the normal of the photovoltaic panel passing through the origin. In the horizontal coordinate system, the direction cosine of the vector OP obtained by vector algebra is:

,

in, , /> , /> are the direction cosines of the vector OP with respect to the x-axis, y-axis, and z-axis;

Let the height angle of solar radiation on the photovoltaic panel be , the azimuth is /> , then its direction cosine:

,

in, , /> , /> are the direction cosines of the solar radiation with respect to the x-axis, y-axis, and z-axis;

by vector algebra , get the sun incidence angle /> for:

.

Further, in step S2, in the power curve directly output by the photovoltaic cell, after Calculate and output the maximum output power of the tracking system at this moment/> , the maximum output power of the tracking system /> Mathematically expressed by a bounded continuous function as:

,

When the height and azimuth of the photovoltaic panel reach the optimal tracking angle, that is, when the photovoltaic panel is in the optimal tracking position, from a mathematical point of view, the following conditions are met:

,

in , /> Represents the altitude angle and azimuth angle when the photovoltaic panel is in the best tracking position,

The total differential of the maximum power can be obtained:

,

in, and /> are the deviations of altitude and azimuth respectively; at the best tracking position, the deviation of the maximum output power is obtained:

,

The two slopes for maximum output power are defined as:

,

in and /> are the maximum output power slopes with respect to altitude and azimuth, respectively.

Further, in step S3, verify that when the photovoltaic panel reaches the ideal tracking position, the maximum output power slope and /> all become zero. The deviation of maximum output power, altitude angle and azimuth angle by /> The controller is computed in discrete form:

,

in, , /> , /> respectively /> The maximum output power, altitude angle and azimuth angle during the analog-to-digital conversion in the controller group data; /> , /> , /> respectively The maximum output power, altitude angle and azimuth angle during the analog-to-digital conversion in the controller group data;

will define the slope and /> Based on the Group data is represented as:

,

in, , /> , /> respectively /> The maximum output power, altitude angle and azimuth angle during the analog-to-digital conversion in the controller group data.

Further, in step S3, by adjusting the azimuth angle and elevation angle of the photovoltaic module, combined with The output result of the tracking system is continuously calculated for the maximum power under the position change of the light tracking system. By comparison /> output power slope and /> Find the maximum output power of the tracking system at the current moment, as well as the best elevation angle and azimuth angle.

In addition, the present invention also proposes a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the specific steps of the aforementioned control method of the present invention are implemented.

Finally, the present invention also proposes an electronic device, including a memory, a processor, and a computer program stored on the memory and operable on the processor, and the processor implements the control method proposed by the present invention when executing the computer program specific steps.

The present invention adopts the above-mentioned technical scheme, and has the following technical effects compared with the prior art:

The current light-following control system mainly adopts open-loop control with large cumulative error and closed-loop control with high cost, while the present invention is based on the analytical relationship between the elevation angle and azimuth angle of the photovoltaic panel and the maximum output power of the internal MPPT controller, and combines Combined with the output power of the post-stage MPPT controller of the photovoltaic cell, by continuously adjusting the altitude angle and azimuth angle, the closed-loop accurate light tracking is realized. This invention improves the efficiency of photovoltaic power generation and reduces the cost of array construction and maintenance. Photovoltaics have strong promotion and application value.

Description of drawings

Fig. 1 is the flow chart of the present invention.

Fig. 2 is a mathematical model of the angle between the photovoltaic panel and the sunlight of the present invention.

Fig. 3 is a diagram for calculating the internal power of the light tracking system in the present invention.

FIG. 4 is a flow chart of the sensorless light tracking control strategy of the present invention.

Detailed ways

The technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, the photovoltaic light tracking control system is installed in parallel between the solar photovoltaic panel and the biaxial tracking bracket. Calculate the correct angle of steering required by the photovoltaic panel, so as to realize the sensorless tracking light control of photovoltaic power generation. The steps to establish the sensorless light tracking control strategy for photovoltaic power generation are as follows:

Step 1: Establish a mathematical model of the angle between the photovoltaic panel and the sun's rays to characterize the direct relationship between the photovoltaic panel and the sun's rays;

Step 2: Establish the height angle of the photovoltaic panel , azimuth /> and maximum output power of photovoltaic modules/> Between the mathematical analytical equations, use the discrete method to calculate the maximum output power curve for the height angle /> and azimuth /> The slope of;

Step 3: Establish a sensorless tracking light control strategy based on the initial position of the photovoltaic panel, and continuously adjust the height angle of the photovoltaic panel and azimuth /> , so that the angle between the normal of the photovoltaic panel and the incident light of the sun is the smallest, and the output power at the current moment is kept at the maximum.

In this embodiment, step 1 is implemented using the following preferred solution:

As shown in Figure 2, the angle between the photovoltaic panel and the horizontal plane is defined as the height angle of the photovoltaic panel , the angle between the projection of the vertical normal of the photovoltaic panel on the horizontal plane and the true south latitude is defined as the azimuth of the photovoltaic panel /> , the angle between the sun's incident light and the normal of the photovoltaic panel is defined as the sun's incident angle /> ; The OP vector is the normal of the photovoltaic panel passing through the origin. In the horizontal coordinate system, the direction cosine of the vector OP obtained by vector algebra is:

,

in, , /> , /> are the direction cosines of the vector OP with respect to the x-axis, y-axis, and z-axis;

Let the height angle of solar radiation on the photovoltaic panel be , the azimuth is /> , then its direction cosine:

,

in, , /> , /> are the direction cosines of the solar radiation with respect to the x-axis, y-axis, and z-axis;

by vector algebra , get the sun incidence angle /> for:

.

In this embodiment, step 2 is implemented using the following preferred solution:

As shown in Figure 3, the value of the maximum power directly output by the photovoltaic panel depends on the height angle of the photovoltaic panel and azimuth , and its maximum value is obtained when the altitude angle reaches the correct tracking altitude angle, similarly, the azimuth angle can be tracked to the best tracking azimuth angle.

In the power curve of the direct output of photovoltaic cells, after Calculate and output the maximum output power of the tracking system at this moment/> , the maximum output power of the tracking system /> Mathematically expressed by a bounded continuous function as:

,

When the height and azimuth of the photovoltaic panel reach the optimal tracking angle, that is, when the photovoltaic panel is in the optimal tracking position, from a mathematical point of view, the following conditions are met:

,

in, , /> Represents the altitude angle and azimuth angle when the photovoltaic panel is in the best tracking position,

The total differential of the maximum power can be obtained:

,

in, and /> are the deviations of altitude and azimuth respectively; at the best tracking position, the deviation of the maximum output power can be obtained:

,

The two slopes for maximum output power are:

,

in and /> are the maximum output power slopes with respect to altitude and azimuth, respectively.

Verify the maximum output power slope when the photovoltaic panel reaches the ideal tracking position and /> become zero, the deviation of maximum output power, altitude angle and azimuth angle is determined by /> The controller is computed in discrete form:

,

in, , /> and /> respectively /> The maximum output power, altitude angle and azimuth angle during the analog-to-digital conversion in the controller group data; /> , /> , /> respectively /> The maximum output power, altitude angle and azimuth angle during the analog-to-digital conversion in the controller group data;

will define the slope and /> Based on the Group data is represented as:

.

in, , /> , /> respectively /> The maximum output power, altitude angle and azimuth angle during the analog-to-digital conversion in the controller group data.

In this embodiment, step 3 is implemented using the following specific process:

A. Select the initial altitude angle and azimuth angle at dawn according to the geographical location of the photovoltaic power generation, so that the photovoltaic panel roughly turns to the point where the sun rises at dawn on the horizon. At the beginning ( ), the angle is /> and /> . The maximum output power of the tracking system associated with these initial angles (/> ) by /> The controller calculates as , where /> and /> are the maximum power point voltage and current collected for the first time, respectively.

B. Track the height angle of the photovoltaic panel ( ), the photovoltaic cell power output curve obtained under this angle is obtained by The controller calculates the maximum power of the light tracking system (/> ), then calculate the slope /> , increase or decrease according to the judgment condition /> , continuous iterative adjustment, the best altitude angle at this moment can be obtained (/> ). save /> Calculate azimuth for next step (/> ) setting value.

Repeat the above process B continuously, and adjust the azimuth and elevation angle of the photovoltaic panel through the stepping motor to get the best azimuth ( ), when the sun’s incident angle is 0°, the sun shines directly on the photovoltaic panel, and the photovoltaic cell outputs the maximum power. The tracking flow chart is shown in Figure 4.

Example 2

An embodiment of the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and operable on the processor. It should be noted that the process of the processor executing the computer program corresponds to the specific steps of the method provided by the embodiment of the present invention, and has corresponding functional modules and beneficial effects for executing the method. For technical details that are not described in detail in this embodiment, refer to the method provided in the embodiment of the present invention, and details are not repeated here.

Example 3

The embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the specific steps of the method provided by the embodiment of the present invention are implemented. For technical details that are not described in detail in this embodiment, refer to the method provided in the embodiment of the present invention, and details are not repeated here.

Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), system-on-chip Implemented in a system of systems (SOC), load programmable logic device (CPLD), computer hardware, firmware, software, and/or combinations thereof. These various embodiments may include being implemented in one or more computer programs executable and/or interpreted on a programmable system including at least one programmable processor, the programmable processor Can be special-purpose or general-purpose programmable processor, can receive data and instruction from storage system, at least one input device, and at least one output device, and transmit data and instruction to this storage system, this at least one input device, and this at least one output device an output device.

Program codes for implementing the methods of the present application may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general-purpose computer, a special purpose computer, or other programmable data processing devices, so that the program codes, when executed by the processor or controller, make the functions/functions specified in the flow diagrams and/or block diagrams Action is implemented. The program code may execute entirely on the machine, partly on the machine, as a stand-alone software package partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present application, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media would include one or more wire-based electrical connections, portable computer disks, hard disks, Random Access Memory (RAM), Read Only Memory (ROM), Erasable Programmable Read Only Memory (EPROM or flash memory), fiber optics, compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

In the description of this specification, descriptions referring to the terms "one embodiment", "example", "specific example" and the like mean that specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment of the present invention. In an embodiment or example. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements are possible, which fall within the scope of the claimed invention.

Claims (8)

1. A sensorless control method for a photovoltaic power generation light tracking system, characterized in that the photovoltaic light tracking control system is installed in parallel between the solar photovoltaic panel and the biaxial tracking support, and the light tracking control system is based on the real-time collected photovoltaic power generation The maximum power signal of the component and the altitude angle and azimuth signal of the solar photovoltaic panel are used to calculate the correct steering angle required by the photovoltaic panel, so as to realize the sensorless tracking light control of photovoltaic power generation; among them, the steps of establishing the sensorless tracking light control strategy of photovoltaic power generation as follows: S1. Establish a mathematical model of the angle between the photovoltaic panel and the sun's rays to represent the direct relationship between the photovoltaic panel and the sun's rays; S2. Establish the height angle of the photovoltaic panel , azimuth /> and maximum output power of photovoltaic modules/> Between the mathematical analytical equations, use the discrete method to calculate the maximum output power curve for the height angle /> and azimuth /> The slope of; S3. Establish a sensorless tracking light control strategy based on the initial position of the photovoltaic panel to continuously adjust the height angle of the photovoltaic panel and azimuth /> , to meet the minimum angle between the normal line of the photovoltaic panel and the incident light of the sun, so that the output power at the current moment can be kept at the maximum value. 2. The sensorless control method of the photovoltaic power generation light tracking system according to claim 1, characterized in that: in step S1, the angle between the photovoltaic panel and the horizontal plane is defined as the height angle of the photovoltaic panel , the angle between the projection of the vertical normal of the photovoltaic panel on the horizontal plane and the true south latitude is defined as the orientation angle of the photovoltaic panel /> , the angle between the sun's incident light and the normal of the photovoltaic panel is defined as the sun's incident angle /> ; The OP vector is the normal of the photovoltaic panel passing through the origin. In the horizontal coordinate system, the direction cosine of the vector OP obtained by vector algebra is: , in , /> , /> are the direction cosines of the vector OP with respect to the x-axis, y-axis, and z-axis; Let the height angle of solar radiation on the photovoltaic panel be , the azimuth is /> , then its direction cosine: , in, , /> , /> are the direction cosines of the solar radiation with respect to the x-axis, y-axis, and z-axis; by vector algebra , get the sun incidence angle /> for: . 3. The sensorless control method of the photovoltaic power generation light tracking system according to claim 1, characterized in that: in step S2, in the power curve directly output by the photovoltaic cell, after Calculate and output the maximum output power of the tracking system at this moment/> , the maximum output power of the tracking system /> Mathematically expressed by a bounded continuous function as: , When the height and azimuth of the photovoltaic panel reach the optimal tracking angle, that is, when the photovoltaic panel is in the optimal tracking position, from a mathematical point of view, the following conditions are met: , in , /> Represents the altitude angle and azimuth angle when the photovoltaic panel is in the best tracking position, That is, the full differential of the maximum power is obtained: , The two slopes for maximum output power are defined as: , in and /> are the maximum output power slopes with respect to altitude and azimuth, respectively. 4. The sensorless control method of the photovoltaic power generation light tracking system according to claim 1, wherein in step S3, the establishment of a sensorless light tracking control strategy based on the initial position of the photovoltaic panel is specifically as follows: Verify the maximum output power slope when the photovoltaic panel reaches the ideal tracking position and /> become zero, the deviation of maximum output power, altitude angle and azimuth angle is determined by /> The controller is computed in discrete form: , in, , /> , /> respectively /> The maximum output power, altitude angle and azimuth angle during the analog-to-digital conversion in the controller group data; /> , /> , /> respectively /> The maximum output power, altitude angle and azimuth angle during the analog-to-digital conversion in the controller group data; will define the slope and /> Based on the Group data is represented as: , in, , /> , /> respectively /> The maximum output power, altitude angle and azimuth angle during the analog-to-digital conversion in the controller group data. 5. The sensorless control method of the photovoltaic power generation light tracking system according to claim 4, characterized in that: in step S3, by adjusting the azimuth angle and elevation angle of the photovoltaic module, combined with The output result of the tracking system is continuously calculated for the maximum power under the position change of the light tracking system. By comparison /> Output Power Slope/> and /> Find the maximum output power of the tracking system at the current moment, as well as the best elevation angle and azimuth angle. 6. The sensorless control method of the photovoltaic power generation light tracking system according to claim 5, characterized in that, in step S3, the specific tracking process of the sensorless light tracking control strategy is as follows: A. Select the initial altitude angle and azimuth angle at dawn according to the geographical location of the photovoltaic power generation, so that the photovoltaic panel initially turns to the point where the sun rises at dawn on the horizon. When , the initial angles of elevation angle and azimuth angle are respectively /> and /> ;The maximum output power of the tracking system associated with these initial angles /> by /> The controller calculates as /> , where /> and /> are the maximum power point voltage and current collected for the first time, respectively; B. Track the height angle of the photovoltaic panel The power output curve of the photovoltaic cell obtained under this angle is obtained by /> The controller calculates the maximum power of the light tracking system/> , then calculate the slope /> , increase or decrease according to the judgment condition /> , continuously iteratively adjust to get the best altitude angle at this moment /> ; save /> Calculate azimuth for next step /> set value; Repeat the above process B continuously, and adjust the azimuth and elevation angle of the photovoltaic panel through the stepping motor to obtain the best azimuth angle , the incident angle of the sun is 0° at this time, the sun shines directly on the photovoltaic panel, and the photovoltaic cell outputs the maximum power. 7. A computer-readable storage medium, on which a computer program is stored, characterized in that, when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are realized. 8. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and operable on the processor, characterized in that, when the processor executes the computer program, any one of claims 1 to 6 is realized. A step of said method.