CN109495063B - Energy Storage Drive System of Seasonally Adjustable Single-axis Photovoltaic Tracking Mount - Google Patents

Abstract

The invention discloses an energy storage drive system of a seasonally adjustable single-axis photovoltaic tracking bracket, which obtains energy input from photovoltaic panels, and includes a capacitor-based short-term electric energy storage subsystem and a counterweight potential energy-based mechanical energy storage system Subsystem, the stored energy is used to drive the seasonally adjustable single-axis photovoltaic tracking bracket to act according to the annual change of the sun's altitude angle. Aiming at the ultra-slow-motion feature of the seasonally adjustable photovoltaic tracking bracket, one round trip a year, the intermittent working mode of the capacitor is designed to charge slowly with a small current and discharge a large current to drive the motor. power requirements, thereby reducing the overall cost of the equipment.

Description

Energy Storage Drive System of Seasonally Adjustable Single-axis Photovoltaic Tracking Mount

technical field

The invention belongs to the technical field of solar tracking devices, and relates to an energy storage drive system of a seasonally adjustable single-axis photovoltaic tracking bracket.

Background technique

Photovoltaic tracking brackets are widely used in the field of solar photovoltaic power generation. Its function is to adjust the working angle of the tracking brackets, so that the photovoltaic panels installed on the brackets track the spatial position of the sun, so as to maximize the reception of solar radiation energy.

The full tracking of the sun's space motion requires two angles of azimuth and elevation tracking. This type of support is called a dual-axis tracking support. In order to improve the cost-effectiveness of the photovoltaic tracking bracket, one of the azimuth and pitch angles can be fixed and only the other is tracked. This tracking bracket is called a single-axis tracking bracket. A uniaxial photovoltaic tracking support whose rotation axis is approximately parallel to the ground plane is called a flat uniaxial. The flat uniaxial photovoltaic tracking bracket can be divided into two types: "north-south flat uniaxial" and "east-west flat uniaxial".

The so-called north-south uniaxial means that the main rotation axis is arranged in the north-south direction, and the normal of the panel plane tracks the change of the sun azimuth angle from east to west; the so-called east-west flat uniaxial refers to the east-west arrangement of the main rotation axis, and the normal direction of the panel Track changes in the sun's altitude. The north-south uniaxial needs to track the sun's azimuth from west to east every day, and return after the sun sets.

Due to the small variation range of the sun's altitude angle during the day, the cosine effect between the solar panel and the sunlight is weak, so the east-west flat single-axis tracking bracket usually does not consider tracking the daily change of the sun's altitude angle. Seasonal changes can adjust the average pitch angle of the photovoltaic tracking bracket. This kind of east-west flat single-axis photovoltaic tracking bracket that adjusts the pitch angle according to the seasonal changes in the year is also called "seasonally adjustable single-axis photovoltaic tracking bracket".

Due to the different laws of tracking actions, the north-south uniaxial tracking bracket that tracks the sun's azimuth in real time every day and the east-west flat uniaxial tracking bracket that adjusts the pitch angle seasonally have the following important differences in structure:

In terms of the mechanical structure of the drive system, due to the frequent movements of the Beiping single shaft, one adjustment round trip is required every day. Therefore, its final drive mechanism mostly adopts a bearing and lubricated structure such as a disc reducer and an electric push rod. Seasonally adjustable east-west flat single shaft adjusts back and forth once a year, and its action frequency is significantly lower than that of north-south flat single shaft, and there are only dozens of adjustment round-trips in the whole life cycle, so its final drive mechanism mostly adopts scissor jack and rack and pinion and other simple drive structures.

In terms of the tracking action principle of the drive system, the real-time action of the Beiping single axis usually needs to be driven by an electric motor, so it needs to be equipped with equipment such as power supply and power supply cable to support the operation of the electric drive system. The drive power supply of the Beiping single-axis usually has two working modes: "centralized distribution of factory power" and "on-site photovoltaic panel power acquisition". When using the centralized distribution method of plant power, a large number of special cables for power supply need to be laid in the photovoltaic power plant, and the construction is complicated and the cost is high. When using the power supply method of direct power supply from on-site photovoltaic panels, the power of the panels is usually required to be equal to the power of the drive motor. And it is necessary to equip the power supply system with a large-capacity battery to ensure that when the solar irradiance drops and the photovoltaic panels generate insufficient power, the tracking system has enough power to return the panels to the next day's power generation position, or in extreme weather. Rotate the panel to the wind-resistant reset position when it cannot generate electricity. Due to the need for large-capacity photovoltaic power generation devices and energy storage batteries, the traditional photovoltaic panel on-site self-consumption work mode requires a large investment in equipment.

However, due to the extremely slow angle change speed of the east-west flat single axis, the working principle of manual adjustment by season or month is usually adopted, which saves the expensive electrical system and effectively reduces the cost of the tracking bracket system. Since the seasonal adjustable east-west flat uniaxial photovoltaic tracking bracket mostly adopts the manual adjustment method according to the season, this kind of photovoltaic tracking bracket is also referred to as "manually adjustable bracket".

The seasonally adjustable photovoltaic tracking bracket adopts the manual adjustment method according to the season. The adjustment time interval is large, which leads to the untimely action of the tracking bracket, and the average cosine effect between the solar panel and the sun light increases, and a certain proportion of photovoltaic power generation is lost. quantity.

The initial construction cost of the seasonally adjustable photovoltaic tracking bracket is low, but the workload of manual manual adjustment during the operation of the power station is large, resulting in high maintenance costs in the later period.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an energy storage drive system of a seasonally adjustable single-axis photovoltaic tracking bracket, which solves the problems of high work intensity and high maintenance cost in the manual adjustment method of the existing seasonally adjustable photovoltaic tracking bracket.

The technical solution adopted in the present invention is that the energy storage drive system of the seasonally adjustable single-axis photovoltaic tracking bracket includes photovoltaic cell panels, and the electric energy output by the photovoltaic cell panels is sent to the DC/DC converter, and the DC/DC converter will obtain the The electric energy is divided into two channels for transmission, one is transmitted to the tracking bracket controller with detection and control functions, which is used to provide working power for the tracking bracket controller; the other channel is output to the energy storage capacitor after voltage level conversion to realize the power storage;

The tracking bracket controller controls the motor driver through signals, the motor driver is used to drive the motor to rotate, and the motor drives the mechanical energy storage mechanism to act.

The present invention is also characterized in that,

The mechanical energy storage mechanism includes a reduction gear box. The input end of the reduction gear box is connected to the main shaft of the motor. The output shaft of the reduction gear box is connected to one end of the input shaft of the attitude adjustment mechanism. The input shaft of the attitude adjustment mechanism is connected to the attitude adjustment mechanism. , the casing of the reduction gear box is connected to the upper end of the sagging drive swing arm.

The driving swing arm is also provided with an inclination sensor, the inclination sensor is used to measure the inclination angle α of the driving swing arm, and the tracking bracket controller is used to read the inclination angle α.

When the length and self-weight of the drive swing arm itself cannot provide a torque greater than or equal to the torque required for the rotation of the input shaft of the attitude adjustment mechanism during the deflection process, the lower end of the drive swing arm is connected with a counterweight block, and the counterweight block is used for: During the rotation process of the driving swing arm, as the swing height H of the driving swing arm increases, the storage of the driving energy of the driving swing arm is realized.

After reading the inclination angle α, the tracking controller can calculate the torque T applied on the input shaft of the attitude adjustment mechanism according to the length L of the driving swing arm and the weight G of the counterweight. When the torque T exceeds the maximum threshold, the tracking bracket controls By sending a signal to the motor driver, the controller stops driving the motor to realize stop protection.

The tracking bracket controller is used to detect the terminal voltage of the energy storage capacitor. When the terminal voltage of the energy storage capacitor rises to a preset value, the tracking bracket controller starts the motor driver through a signal, and uses the electric energy stored in the energy storage capacitor to drive the motor to rotate.

When the rated power of the photovoltaic panel and the rated power of the DC/DC converter are both less than the rated power of the motor, the electric power for driving the motor can be generated only by the energy storage of the energy storage capacitor. After the energy storage of the energy storage capacitor is completed, The maximum time for the motor to consume the electric energy stored in the energy storage capacitor to complete a motor drive does not exceed 30s.

The beneficial effect of the present invention is that the energy storage drive system of the seasonally adjustable single-axis photovoltaic tracking bracket of the present invention adopts the low-power energy output by the photovoltaic panel to drive the photovoltaic tracking bracket through energy storage, which simplifies the structure of the power supply device and reduces the cost; Aiming at the characteristics of the slow-speed action of the seasonal adjustable bracket and no energy storage return requirements, capacitors are used to replace the large-capacity energy storage batteries commonly used in photovoltaic tracking systems, which avoids battery life and maintenance problems; the swing arm structure is used to control the motor output The mechanical potential energy is stored, which simplifies the support structure of the electric drive device and improves the transmission efficiency.

Description of drawings

1 is a schematic structural diagram of an energy storage drive system of a seasonally adjustable uniaxial photovoltaic tracking bracket of the present invention;

Fig. 2 is the installation schematic diagram of the energy storage drive system of the seasonal adjustable single-axis photovoltaic tracking support of the present invention on the photovoltaic support;

3 is a schematic diagram of the connection structure of the mechanical energy storage mechanism and the input shaft of the attitude adjustment mechanism in the energy storage drive system of the seasonally adjustable single-axis photovoltaic tracking bracket of the present invention;

4 is a schematic diagram of the connection structure of the attitude adjustment mechanism and the input shaft of the attitude adjustment mechanism in the energy storage drive system of the seasonally adjustable single-axis photovoltaic tracking bracket of the present invention;

5 is a schematic diagram of the circuit connection of the DC/DC converter, the energy storage capacitor and the motor driver bracket in the energy storage drive system of the seasonally adjustable single-axis photovoltaic tracking bracket of the present invention;

6(a) and (b) are schematic diagrams of the state in which the rotation of the seasonally adjustable single-axis photovoltaic tracking support drives the rotation of the swing arm in the energy storage drive system of the seasonally adjustable single-axis photovoltaic tracking support of the present invention.

In the figure, 1. Photovoltaic panel, 2. Tracking bracket controller, 3. DC/DC converter, 4. Energy storage capacitor, 5. Motor driver, 6. Electric motor, 7. Reduction gearbox, 8. Gear box output Axis, 9. Attitude adjustment mechanism, 10. Seasonally adjustable single-axis photovoltaic tracking bracket, 11. Attitude adjustment mechanism input shaft, 12. High-power battery panel group, 13. Drive swing arm, 14. Counterweight, 15. Inclination Sensor 16. Pitching mechanism beam, 17. Pitching axis, 18. Tracking support column, 19. Upper endpoint of attitude adjustment mechanism, 20. Lower endpoint of attitude adjustment mechanism, 21. Scissor jack support arm, 22. Scissor jack horizontal endpoint, 23. DC/DC controller.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The energy storage drive system of the seasonally adjustable single-axis photovoltaic tracking bracket of the present invention, as shown in Figures 1 to 3, includes a photovoltaic cell panel 1, and the electrical energy output by the photovoltaic cell panel 1 is sequentially transmitted to the DC/DC converter 3, the energy storage The capacitor 4, the motor driver 5 and the motor 6, and the motor 6 is connected with a mechanical energy storage mechanism;

It also includes a tracking support controller 2, and the tracking support controller 2 is respectively connected with the DC/DC converter 3, the energy storage capacitor 4 and the motor driver 5.

The mechanical energy storage mechanism includes a reduction gear box 7, the input end of the reduction gear box 7 is connected with the main shaft of the electric motor 6, the gear box output shaft 8 of the reduction gear box 7 is connected with one end of the input shaft 11 of the attitude adjustment mechanism, and the input shaft of the attitude adjustment mechanism 11 is connected to the posture adjustment mechanism 9 . The casing of the reduction gear box 7 is connected to the upper end of the drive swing arm 13 which is provided downwardly. The reduction gear box 7 has a self-locking structure.

The driving swing arm 13 is also provided with an inclination sensor 15 , and the inclination sensor 15 is connected with the tracking bracket controller 2 .

A counterweight 14 is connected to the lower end of the driving swing arm 13 .

The seasonally adjustable single-axis photovoltaic tracking bracket 10 includes a high-power battery panel group 12, and the high-power battery panel group 12 is mounted on a pitching mechanism beam 16, and the pitching mechanism beam 16 is connected to the upper part of the tracking support column 18 through the pitching shaft 17, and the attitude is adjusted. The mechanism 9 can choose a common transmission form such as a scissor jack, a lead screw or a rack and pinion. In this embodiment, the posture adjustment mechanism 9 adopts the existing scissor jack; the photovoltaic tracking bracket driven by the scissor jack is used as an example for illustration. .

Scissor jack is a common lifting device. As shown in Figure 4, it consists of four scissor jack support arms 21 hinged in a rhombus shape, and horizontally arranged in the middle of the four scissor jack support arms 21. Rotate the adjusting lead screw. In this embodiment, the lower node of the scissor jack, that is, the lower end point 20 of the attitude adjustment mechanism, is connected to the tracking support column 18 through a rotatable hinge. The upper node of the scissor jack, that is, the upper end point 19 of the attitude adjustment mechanism, is connected to the beam 16 of the pitch mechanism through a rotatable hinge. When the horizontal adjustment screw of the scissor jack, that is, the input shaft 11 of the attitude adjustment mechanism, rotates, the distance between the upper end point 19 of the attitude adjustment mechanism and the lower end point 20 of the attitude adjustment mechanism can be changed. When the distance between the upper end point 19 of the attitude adjustment mechanism and the lower end point 20 of the attitude adjustment mechanism changes, the beam 16 of the pitch mechanism can be driven to rotate around the pitch axis 17 to achieve the purpose of adjusting the pitch angle of the high-power battery panel group 12 .

Taking reducing the pitch angle as an example, the input shaft 11 of the attitude adjustment mechanism rotates, and under the action of the screw screw and the nut, the distance between the two horizontal endpoints of the scissor jack decreases, and the upper endpoint 19 of the attitude adjustment structure and the attitude adjustment structure The height between the lower end points 20 is increased to realize the pushing function of the beam 16 of the pitch mechanism. Under the pushing action of the scissor jack, the beam 16 of the pitching mechanism rotates in the horizontal direction around the pitching axis 17 , thereby realizing the reduction and adjustment of the pitching angle of the high-power battery panel group 12 . The adjustment process for increasing the pitch angle of the high-power battery panel group 12 is similar to this but in the opposite direction.

Scissor jacks can be installed individually or in series on a seasonally adjustable single-axis photovoltaic tracking bracket. When installing in series, the shafts of different jacks need to be connected in series to rotate synchronously. The situation is similar when driving mechanisms such as lead screw and rack and pinion are applied to seasonally adjustable single-axis photovoltaic tracking brackets. The unifying feature is that there is a horizontally arranged input shaft. The distance between the upper and lower end points of the mechanism changes, so as to realize the adjustment of the angle of the beam 16 of the pitch mechanism.

To adjust the pitch angle of the high-power battery panel group 12 on the seasonally adjustable photovoltaic support, it is necessary to rotate the attitude adjustment mechanism input shaft 11 of the attitude adjustment mechanism 9 . When the end of the input shaft 11 of the attitude adjustment mechanism is displaced, the energy storage drive system structure composed of the DC/DC converter 3, the energy storage capacitor 4, the motor driver 5 and the motor 6 in the present invention can move accordingly.

The tracking bracket controller 2 is a kind of control device that all automatic adjustment tracking photovoltaic brackets must have. The deviation automatically sends out instructions to control the motor, and the motor drives the tracking bracket to reach the target angle range. At the same time, functions such as power management, working state monitoring and safety protection can also be realized by means of the computing processing capability of the tracking bracket controller 2 . The present invention adds the management function of the energy storage power source on the basis of the existing photovoltaic tracking support controller 2 .

The core of the present invention lies in the energy storage power system of the seasonally adjustable single-axis photovoltaic tracking support. The specific method of the tracking support controller 2 to detect and control the pitch angle of the high-power battery panel group does not affect the realization of the technical solution of the present invention. The tracking support controls The specific installation position of the device 2 does not affect the realization of the technical solution of the present invention.

The parameters of the power supply part in the energy storage drive system of the seasonally adjustable single-axis photovoltaic tracking bracket of the present invention are as follows:

Photovoltaic panel 1: rated voltage DC6V, rated current 200mA, power 1.2W;

Motor 6: rated voltage 12V, rated current 2.2A, power > 25W, starting current 4.5A.

DC/DC converter 3: input voltage 2-7V, maximum input working current 250mA.

As shown in FIG. 5 , the electrical energy output by the photovoltaic panel 1 is sent to the DC/DC converter 3 . The DC/DC converter 3 is composed of a DC/DC controller 23 and peripheral electrical components, and its core function is to realize the energy storage capacitor 4 of charging energy. The energy storage capacitor 4 is composed of a total of 4 supercapacitors C1, C2, C3, and C4 with a withstand voltage of 5.5V and a capacity of 4F in series. The internal resistance of a single capacitor is 200mΩ, the rated current is 2.5A, and the maximum working current is 10.0A. The capacity of the energy storage capacitor bank after being connected in series is 1.0F, the withstand voltage is 22V, and the internal resistance is 0.8Ω.

In order to prevent the overvoltage of the individual capacitors caused by the difference in internal resistance of the series capacitors, each capacitor is configured with 5.6V Zener diodes D11, D12, D13, and D14 in parallel for voltage equalization. Zener diodes provide a current bypass loop when a single capacitor overvoltage occurs.

The DC/DC converter 3 in this embodiment adopts a controllable boost DC/DC converter with MPPT tracking function, and the entire circuit is a Boost structure. The DC/DC controller 23 controls the MOSFET transistor Q1 through the DRV port to form a boost circuit with the inductor L1 and the diode D0. During the charging process, the DC/DC controller 23 detects the charging current on the sampling resistor R8 through the ports CSP and CSN, so as to realize the constant current charging of the energy storage capacitor 4 . The circuit inputs the terminal voltage of the capacitor bank to the FB feedback measurement terminal of the DC/DC controller 23 through the voltage dividing resistors R7 and R6. When the terminal voltage of the capacitor bank rises to the preset 20V, the DC/DC controller 23 stops working. The charging process ends.

In order to realize the signal connection between the capacitor charging circuit composed of the DC/DC converter 3 and the energy storage capacitor 4 and the tracking bracket controller 2, the DC/DC controller 23 in the DC/DC converter 3 can receive the signal through the SHDN port Start and stop commands from Track Stand Controller 2. When the SHDN port is at a low level, the energy storage capacitor 4 is charged, and when the SHDN port is at a high level, the energy storage capacitor 4 stops charging. During the charging process of the energy storage capacitor 4, the CHRG terminal of the DC/DC controller 23 is at a low level. When charging to the preset 20V voltage, the CHRG terminal outputs a high level, which informs the tracking bracket controller 2 and the energy storage capacitor 4. After charging, it has working conditions.

During the charging process, the DC/DC controller 23 detects the inductor current flowing on Q1 through the sampling resistor R5, and then enters the DC/DC controller 23 through the filter circuit formed by R4 and C02 to realize the detection and protection of the inductor working current. .

When the light intensity is insufficient, the output energy of the photovoltaic panel 1 is insufficient, and the energy storage capacitor 4 cannot be charged according to the preset rated current. The DC/DC controller 23 inputs the voltage state of the photovoltaic panel 1 through the MPPT port through the sampling resistor network R1 and R2. When the voltage of the photovoltaic panel 1 is lower than the rated value of 6V, the DC/DC controller 23 automatically adjusts the charging current setting. Set value, reduce the actual charging current value, realize the maximum power tracking of photovoltaic panel 1 power, referred to as MPPT control.

In FIG. 5 , the electrical energy output by the photovoltaic cell panel 1 is branched into a power source inside the DC/DC converter 3 to provide working power to the tracking bracket controller 2 . The DC/DC converter 3 circuit can provide power to the tracking bracket controller 2 before and after the voltage conversion according to the situation. In this embodiment, power is provided before voltage conversion.

When the charging is completed, if the angle deviation of the tracking bracket exceeds the limit, the tracking bracket controller 2 can start the motor driver 5 to drive the motor 6 . In this embodiment, the motor driver 5 is an H-bridge type DC motor drive circuit composed of four transistors Q1, Q2, Q3, and Q4. It includes a PWM type step-down drive function, which can convert the 20.0-14.0V capacitor bank terminal voltage. Step down to 12V output, the maximum starting current is >5A, and the rated operation is 2.2A.

Under this working parameter, the electric energy released by the energy storage capacitor 4 with an equivalent capacitance of 1.0 Farad from 20V to 14V in one discharge is:

W=0.5CU ² =0.5×1×20×20=200J.

W= ^0.5CU2 =0.5×1×14×14=98J.

The maximum discharge capacity is 102J=200J-98J

Assuming that the efficiency of the H-bridge PWM drive circuit is about 85%, the effective output of the 102 joules of energy storage is about 86.7 joules, which can drive the 25W motor 6 to work for more than 3.47s. After the motor 6 is decelerated by the reduction gear box 7, the speed of the output shaft 8 of the gear box is set to be 0.5 RPM, and it can rotate more than 10.4 degrees in 3.47 s.

When the irradiance reaches the rated value of the panel, the power of the photovoltaic panel 1 is 1.2W, and the conversion efficiency of the boost circuit is set to be 82%, then the charging power is 0.98W. It takes 100s to charge 98J of electricity.

Due to the capacitor energy storage structure, the power of the photovoltaic panel 1 is significantly smaller than the power of the motor 6 , and the power of the photovoltaic panel 1 can reach 10% or even less than the power of the motor 6 . While reducing the cost of the photovoltaic cell panel 1, the volume is also reduced, which is convenient for on-site installation. Compared with the battery, the energy storage capacitor 4 has a small power storage capacity and a short power storage time, but it just meets the slow intermittent driving requirements of the seasonal leveling single-axis support.

The parameters set in this embodiment are that the length of the driving swing arm 13 is L=0.5m, the mass of the counterweight 14 is m=4Kg, and the weight of the counterweight 14 is G=mg.

Without loss of generality, as shown in Figure 6(a), Figure 6(a) is a diagram of the initial installation state of the drive swing arm; after the initial installation, the drive swing arm 13 is vertically downward, and the output shaft 8 of the gear box is input to the attitude adjustment mechanism. Shaft 11 has no torque output. As shown in Fig. 6(b), 6(b) is a schematic diagram of the state of driving the swing arm 13 with the rotation angle α of the input shaft 11 of the attitude adjustment mechanism; Under the action of swinging to the left, as the driving system continuously obtains the rotation of the solar-powered motor 6, the declination angle α of the driving swing arm 13 continues to increase, and the height increment H of the counterweight 14 continues to increase, so as to achieve the purpose of mechanical energy storage driving. .

The stored energy E can be calculated by the following formula

E=mg H=mg(L-L×cosα) (1);

The torque formed by simultaneously driving the swing arm 13 and the counterweight 14 to the input shaft 11 of the attitude adjustment mechanism can be calculated by the following formula:

T = mg L sinα (2);

When the declination angle α of the driving swing arm is 90 degrees, the torque formed by the driving swing arm 13 and the counterweight 14 to the input shaft 11 of the attitude adjustment mechanism is the largest. In this example, L=0.5m, and the mass of the counterweight 14 is 4Kg. Below, the maximum input torque is: T=4×9.8×0.5×1=19.6N.m.

Assuming that the input shaft 11 of the attitude adjustment mechanism rotates 100 times and the pitch angle of the tracking bracket is adjusted by 45 degrees, the average rotation reduction ratio is 800, assuming that the transmission efficiency of this scissor jack (attitude adjustment mechanism 9) in this example is 30%. At the same time, it is assumed that the torque requirement of the final stage panel adjustment of the tracking bracket is 1920N.m.

Then the input torque requirement is 8N.m (1920=800×30%×8)

Assuming that the torque requirement of the attitude adjusting mechanism 9 to overcome the static friction rotation is 8N.m, the input torque requirement to start the action of the tracking bracket is:

T=8+8=16N.m

When the angle increases to α=54.8 degrees, the input torque T=4×9.8×0.5×sin54.8=16N.m. At this time, after the input torque of 16N.m overcomes the static friction torque of 8N.m, the seasonal adjustable single shaft The input shaft 11 of the attitude adjustment mechanism of the photovoltaic tracking bracket 10 inputs a net torque of 8 N.m. Under the conditions of a reduction ratio of 800 times and a transmission efficiency of 30%, a torque of 1920 N.m can be input to the last stage solar panel bracket, thereby driving the seasonal adjustable single-axis photovoltaic tracking bracket 10 to start to rotate, the counterweight 14 to start to fall, and at the same time The deflection angle α decreases.

Assuming that the torque requirement of the drive mechanism of the seasonally adjustable single-axis photovoltaic tracking bracket 10 to overcome the dynamic friction is 2N.m, when the declination angle continues to drop below α=30.7 degrees, the input torque is less than T=4×9.8×0.5×sin30.7 =10.0N.m, the input torque of the driving swing arm 13 is less than the sum of the torque to overcome the resistance of the seasonally adjustable single-axis photovoltaic tracking bracket 10 of 8N.m and the kinetic friction of 2N.m, and the input shaft 11 of the attitude adjustment mechanism stops moving.

In this example, the declination angle α of the seasonally adjustable uniaxial photovoltaic tracking bracket 10 increases from 0° to 54.7 degrees, and the process of driving the seasonally adjustable uniaxial photovoltaic tracking bracket 10 back to 30.7 degrees after the action is driven is one drive adjustment. The action range is 24 degrees and requires 2-3 times of energy storage by the electrical system. After the first drive adjustment is completed, the system continues to increase the declination angle α under the action of the motor 6 and the reduction gear box 7, and starts the next adjustment process.

When α=54.7 degrees, the potential energy of driving the swing arm 13 and the counterweight 14 is:

E=4×9.8×(0.5(1-cos54.7°))=4×9.8×0.422=16.5J

When α=30.7 degrees, the potential energy of driving the swing arm 13 and the counterweight 14 is:

E=4×9.8×(0.5(1-cos30.7°))=4×9.8×0.14=5.5J

The energy released is 16.5-5.5=11 joules.

During the operation of the driving swing arm 13, the inclination sensor 15 can actually measure the inclination angle α of the driving swing arm, and can obtain the driving torque T by calculating the above formula (2). When the driving swing arm 13 reaches the horizontal position, the driving torque T can be Reaches the maximum value. The maximum driving torque T of the system can be controlled by adjusting the length L of the driving swing arm 13 and the weight G of the counterweight 14 .

When a mechanical failure occurs and the bracket cannot rotate, the declination angle α continues to increase. The tracking bracket controller 2 measures the declination angle α through the inclination sensor 15 and calculates the driving torque T of the input shaft 11 of the attitude adjustment mechanism to achieve maximum torque protection. In this example, the torque overrun alarm is set when α>=75 degrees, and the corresponding protection torque at this time is:

T=4×9.8×0.5×sin75=19.0N.m

When α exceeds 75 degrees after the maximum set value, and the torque exceeds 19.0N.m, the system will stop the motor 6 driving and give an alarm to realize stop protection.

In the energy storage drive system of the seasonally adjustable single-axis photovoltaic tracking bracket of the present invention, the rated power of the photovoltaic panel 1 and the rated power of the DC/DC converter 3 are both less than 20% of the rated power of the motor 6, and it is necessary to pass the energy storage. The energy storage of the capacitor 4 can generate the electric power for driving the electric motor 6 to work. After the energy storage is completed, the electric motor 6 consumes the electric energy stored in the energy storage capacitor 4 to complete a short-term motor 6 drive. The longest time does not exceed 30s;

The photovoltaic cell panels 1 can be set individually, or can be taken from a high-power cell panel group 12 .

In the present invention, the capacitor energy storage structure and the mechanical energy storage mechanism can be used in combination to form a whole, or they can be used separately and independently.

When the length and self-weight of the driving swing arm 13 can provide a torque greater than that required for the rotation of the input shaft 11 of the attitude adjustment mechanism after deflection, the counterweight 14 can be eliminated.

The characteristics of the energy storage drive system of the seasonally adjustable single-axis photovoltaic tracking bracket of the present invention are that it is aimed at the problem of low driving efficiency caused by the intermittent short-term action machinery that needs to overcome the static friction force frequently, and the position of the end of the drive shaft changes with the attitude of the bracket. A mechanical energy storage subsystem based on the suspension swing arm and the counterweight block is designed. Through the cooperation of the suspension pendulum arm and the counterweight block, the driving torque is input to the drive shaft of the tracking bracket, and at the same time, the increased potential energy is rotated with the help of the counterweight block. Realize mechanical energy storage, achieve the purpose of simplifying the installation method of the drive mechanism and improving the energy utilization efficiency.

Claims (6)

1. The energy-storage drive system of the seasonally adjustable single-axis photovoltaic tracking support, is characterized in that: the system is used for the drive of the seasonally adjustable photovoltaic tracking support for intermittently adjusting the pitch angle of the photovoltaic panel according to the season, including the photovoltaic cell panel (1 ), the electrical energy output by the photovoltaic panel (1) is sent to the DC/DC converter (3), and the DC/DC converter (3) divides the obtained electrical energy into two channels for transmission, and one channel is transmitted to the detection and control function. The tracking bracket controller (2) is used to provide the working power supply for the tracking bracket controller (2); the other channel is output to the energy storage capacitor (4) after voltage level conversion to realize electric energy storage; The tracking bracket controller (2) controls the motor driver (5) through signals, the motor driver (5) is used to drive the motor (6) to rotate, and the motor (6) drives the mechanical energy storage mechanism to act; The DC/DC converter (3) includes a DC/DC controller (23), and the function of the DC/DC converter (3) is to realize the charging and energy storage of the energy storage capacitor; The mechanical energy storage mechanism comprises a reduction gear box (7), the input end of the reduction gear box (7) is connected with the main shaft of the electric motor (6), and the gear box output shaft (8) of the reduction gear box (7) is connected with the attitude adjustment. One end of the mechanism input shaft (11), the attitude adjustment mechanism input shaft (11) is connected to the attitude adjustment mechanism (9), and the casing of the reduction gear box (7) is connected to the upper end of the sagging drive swing arm (13). 2. The energy-storage drive system of the seasonally adjustable single-axis photovoltaic tracking bracket according to claim 1, wherein the drive swing arm (13) is further provided with an inclination sensor (15), and the inclination sensor ( 15) Used to measure the inclination angle α of the driving swing arm (13), and the tracking bracket controller (2) is used to read the inclination angle α. 3. The energy storage drive system of the seasonally adjustable single-axis photovoltaic tracking support according to claim 2, characterized in that: when the length and self-weight of the drive swing arm (13) itself cannot provide a value greater than or When it is equal to the torque required for the rotation of the input shaft (11) of the attitude adjustment mechanism, a counterweight (14) is connected to the lower end of the driving swing arm (13), and the counterweight (14) is used for: driving the swing arm (13) During the rotation process, as the swing height H of the driving swing arm (13) increases, the storage of the driving energy of the driving swing arm (13) is realized. 4. The energy storage drive system of a seasonally adjustable single-axis photovoltaic tracking bracket according to claim 3, characterized in that: after reading the inclination angle α, the tracking bracket controller (2) can The length L of the swing arm (13) and the weight G of the counterweight (14) are calculated to obtain the torque T applied on the input shaft (11) of the attitude adjustment mechanism. When the torque T exceeds the maximum threshold, the tracking bracket controller (2) passes the A signal is sent to the motor driver (5) to stop the driving of the motor (6) to realize stop protection. 5. The energy storage drive system of a seasonally adjustable single-axis photovoltaic tracking bracket according to claim 1, wherein the tracking bracket controller (2) is used to detect the port voltage of the energy storage capacitor (4), When the terminal voltage of the energy storage capacitor (4) rises to a preset value, the tracking support controller (2) starts the motor driver (5) through a signal, and uses the electric energy stored in the energy storage capacitor (4) to drive the motor (6) rotate. 6. The energy storage drive system of the seasonally adjustable single-axis photovoltaic tracking bracket according to claim 5, characterized in that: when the rated power of the photovoltaic panel (1) is equal to that of the DC/DC converter (3) The rated power is smaller than the rated power of the electric motor (6), and the electric power for driving the electric motor (6) can only be generated by the energy storage of the energy storage capacitor (4). After the energy storage of the energy storage capacitor (4) is completed, the electric motor (6) consumes The maximum time for the electric energy stored in the energy storage capacitor (4) to complete the driving of the electric motor (6) once is not more than 30s.

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