A control method for optical storage topology

Abstract

The present invention discloses a control method for a photovoltaic storage topology, including: collecting input and output parameters and battery parameters of a photovoltaic storage topology circuit, performing voltage conversion and A / D conversion through an integrated operational amplifier to obtain a 1ms AD sampling value, calculating the input power and obtaining the target output power through an external signal instruction; before the photovoltaic storage system is turned on, performing a self-check on the photovoltaic storage topology circuit; during the self-check, first judging whether a battery exists according to the battery parameters, and if no battery exists, further judging whether a micro-inverter exists, and if a micro-inverter exists, entering a pure output mode, and if no micro-inverter exists, shutting down the bypass and re-performing a self-check; if a battery exists, switching the working mode according to the input power and the target output power. The present invention switches the working mode according to the input power and the target output power of the photovoltaic storage topology circuit, realizes the effective storage of excess electric energy, and solves the problem of insufficient power supply on cloudy days or at night.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic storage technology, and in particular to a control method for photovoltaic storage topology. Background Art

[0002] As the global demand for renewable energy grows, photovoltaic power generation has been widely used as a clean and renewable energy form. However, despite its significant advantages in reducing greenhouse gas emissions and promoting energy diversification, photovoltaic power generation also faces some challenges in its practical application, one of which is the problem of power waste.

[0003] The output power of photovoltaic power generation systems is affected by factors such as sunshine intensity and weather conditions, and has obvious volatility and intermittency. For example, on a sunny day, photovoltaic panels can generate a large amount of electricity, but the actual electricity demand of the family may not be high at this time, resulting in some electricity being unable to be effectively utilized, which in turn causes electricity waste, and the excess electricity cannot be effectively stored. On cloudy days or at night, photovoltaic panels cannot generate a large amount of electricity, but the actual electricity demand of the family is relatively high at this time, and photovoltaic inverters alone cannot guarantee the electricity demand on cloudy days and at night. Summary of the invention

[0004] Based on this, the present invention provides a control method for a photovoltaic storage topology to solve the problem that excess electrical energy cannot be effectively stored, resulting in insufficient power supply on cloudy days and at night.

[0005] The present invention provides a control method for an optical storage topology, comprising:

[0006] Collect the input and output parameters of the photovoltaic storage topology circuit and the battery parameters, and perform voltage conversion and A / D conversion through the integrated operational amplifier to obtain the 1ms AD sampling value, calculate the input power Pin and obtain the target output power Pout through external signal instructions;

[0007] Before the photovoltaic storage system is turned on, a self-test is performed on the photovoltaic storage topology circuit;

[0008] During self-test, first determine whether there is a battery in the photovoltaic storage topology circuit based on the battery parameters. If there is no battery, further determine whether there is a micro-inverter in the photovoltaic storage topology circuit. If there is a micro-inverter, the photovoltaic storage topology circuit enters a pure output mode. If there is no micro-inverter, the bypass is shut down and self-test is performed again; if there is a battery, the working mode is switched according to the input power and target output power of the photovoltaic storage topology circuit.

[0009] This includes, if there is no battery, opening the photovoltaic panel direct loop, waiting for Ns, and judging whether there is a micro inverter based on whether there is current output.

[0010] The photovoltaic panel direct connection circuit includes a fifth MOS transistor and a sixth MOS transistor. The drain of the fifth MOS transistor is electrically connected to the positive electrode of the photovoltaic panel. The source of the fifth MOS transistor is electrically connected to the source of the sixth MOS transistor. The drain of the sixth MOS transistor is connected to the output load.

[0011] If there is no battery and no micro-inverter, the photovoltaic panel direct connection circuit is turned off, indicating that the starting conditions are not met, and self-checking is performed again.

[0012] If there is no battery but there is a micro-inverter, enter the pure output mode. In the photovoltaic and energy storage topology circuit, turn on the fifth MOS transistor and the sixth MOS transistor, turn off other MOS transistors, and the photovoltaic panel is connected to the micro-inverter through the photovoltaic panel direct connection circuit.

[0013] If there is a battery, further determine whether the voltage of the photovoltaic panel is normal. If the voltage of the photovoltaic panel is abnormal, turn on the Buck circuit to control the output voltage, wait for Ns, and determine whether there is a micro-inverter according to whether there is current output. If there is current output, there is a micro-inverter, and enter the pure discharge mode where the battery discharges the micro-inverter; if there is no current output, there is no micro-inverter, indicating that the starting conditions are not met, and self-checking is performed again.

[0014] If there is a battery and the voltage of the photovoltaic panel is normal, turn on the Buck-Boost circuit to control the battery voltage. After the battery operates stably, turn on the Buck circuit transistor to control the output voltage, wait for Ns, and determine whether there is a micro-inverter according to whether there is current output.

[0015] If the voltage of the photovoltaic panel is normal but there is no micro-inverter, the photovoltaic and energy storage topology circuit enters the pure charging mode, and the photovoltaic panel charges the battery.

[0016] If the voltage of the photovoltaic panel is normal and there is a micro-inverter, compare the magnitudes of Pin and Pout. If Pin > Pout, enter the charging and outputting mode simultaneously; if Pin < Pout, enter the discharging and outputting mode simultaneously.

[0017] When in the charging and outputting mode simultaneously, due to the weakening of the light intensity, Pin becomes smaller, resulting in Pin < Pout, and the working mode switches from the charging and outputting mode simultaneously to the discharging and outputting mode simultaneously.

[0018] When in the discharging and outputting mode simultaneously, due to the enhancement of the light intensity, Pin becomes larger, resulting in Pin > Pout, and the working mode switches from the discharging and outputting mode simultaneously to the charging and outputting mode simultaneously.

[0019] Beneficial effects: The present invention switches the working mode according to the input power and the target output power of the photovoltaic and energy storage topology circuit, enabling the excess photovoltaic electric energy to be effectively stored in the battery and ensuring sufficient power output when the photovoltaic electric energy is insufficient.

[0020] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are used to better understand the present invention and do not constitute a limitation of the present invention.

[0022] Figure 1 It is a schematic diagram of a photoelectric storage topology circuit provided according to the present invention. DETAILED DESCRIPTION

[0023] The following is a description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0024] The present invention provides a control method for a photovoltaic storage topology, wherein the photovoltaic storage topology circuit diagram is as follows: Figure 1 As shown, including:

[0025] S1: Collect the input and output parameters of the photovoltaic storage topology circuit and the battery parameters, and perform voltage conversion and A / D conversion through the integrated operational amplifier to obtain the 1ms AD sampling value, calculate the input power Pin and obtain the target output power Pout through external signal instructions;

[0026] S2: before the photovoltaic storage system is turned on, self-checking the photovoltaic storage topology circuit;

[0027] There is a self-check process before starting up to check the input, battery, and output of the photovoltaic storage system to ensure that the photovoltaic storage system starts up in a safe manner, thereby improving the safety of the system.

[0028] S3: During self-check, first determine whether there is a battery in the photovoltaic storage topology circuit according to the battery parameters. If there is no battery, further determine whether there is a micro inverter in the photovoltaic storage topology circuit. If there is a micro inverter, the photovoltaic storage topology circuit enters the pure output mode. If there is no micro inverter, shut down the bypass and re-check the self-check; if there is a battery, switch the working mode according to the input power and target output power of the photovoltaic storage topology circuit. It should be noted that:

[0029] The purpose of self-test before starting the device is to obtain the battery status, the photovoltaic panel input status, and whether the device output is connected to a micro-inverter. If the battery is normal, the photovoltaic panel has input voltage, and the output is connected to a micro-inverter, then everything is normal and the device can work normally.

[0030] Self-test before startup. Before starting the optical storage system, perform a self-test. The self-test process is as follows:

[0031] Firstly, according to the battery parameters, it is determined whether there is a battery in the photovoltaic storage topology circuit;

[0032] If there is no battery, open the photovoltaic panel direct circuit, wait for Ns, and determine whether there is a micro inverter based on whether there is current output.

[0033] Furthermore, the micro inverter has a startup time, and the judgment can only be made after the micro inverter is started. This waiting time Ns only needs to be greater than the startup time of the micro inverter.

[0034] If there is no battery and no micro-inverter, the photovoltaic panel direct circuit is closed, and a prompt is given that the startup conditions are not met, and the self-test is performed again.

[0035] If there is no battery but there is a micro inverter, it enters the pure output mode. In the photovoltaic storage topology circuit, the fifth MOS tube and the sixth MOS tube are turned on, and the other MOS tubes are turned off. The photovoltaic panel is connected to the micro inverter through the photovoltaic panel direct loop.

[0036] If there is a battery, it is further determined whether the photovoltaic panel voltage is normal. If the photovoltaic panel voltage is abnormal, the Buck circuit is turned on to control the output voltage and wait for Ns. Based on whether there is current output, it is determined whether there is a micro inverter. If there is current output, there is a micro inverter and the pure discharge mode is entered to discharge the micro inverter with the battery. If there is no current output, there is no micro inverter, indicating that the startup conditions are not met and the self-check is performed again.

[0037] When the Buck-Boost circuit is turned on to control the battery voltage, if the photovoltaic panel voltage is greater than the battery voltage, the first MOS tube Q1 and the second MOS tube Q2 are alternately turned on with a certain duty cycle, and the third MOS tube Q3 is always in a closed state to achieve voltage reduction; if the photovoltaic panel voltage is less than the battery voltage, the first MOS tube Q1 is always in a conducting state, the second MOS tube Q2 is always in a closed state, the third MOS tube Q3 is turned on with a certain duty cycle to achieve voltage boost, wait for Ns, and the fourth MOS tube Q4 is turned on with a certain duty cycle to achieve voltage reduction to the operating voltage range allowed by the micro inverter.

[0038] If there is a battery and the voltage of the photovoltaic panel is normal, turn on the Buck-Boost circuit to control the battery voltage. After the battery operates stably, turn on the Buck circuit transistor to control the output voltage. Wait for Ns, and determine whether there is a micro-inverter according to whether there is current output.

[0039] If the voltage of the photovoltaic panel is normal but there is no micro-inverter, the photovoltaic-battery topology circuit enters the pure charging mode, and the photovoltaic panel charges the battery.

[0040] If the voltage of the photovoltaic panel is normal and there is a micro-inverter, compare the magnitudes of Pin and Pout. If Pin > Pout, enter the charging-and-output mode. If Pin < Pout, enter the discharging-and-output mode.

[0041] When in the charging-and-output mode, due to the weakening of the light intensity, Pin becomes smaller, making Pin < Pout, and the working mode switches from the charging-and-output mode to the discharging-and-output mode.

[0042] When in the discharging-and-output mode, due to the enhancement of the light intensity, Pin becomes larger, making Pin > Pout, and the working mode switches from the discharging-and-output mode to the charging-and-output mode.

[0043] The photovoltaic panel direct-through circuit includes a fifth MOS transistor Q5 and a sixth MOS transistor Q6. The drain of the fifth MOS transistor Q5 is electrically connected to the positive electrode of the photovoltaic panel. The source of the fifth MOS transistor Q5 is electrically connected to the source of the sixth MOS transistor Q6. The drain of the sixth MOS transistor Q6 is connected to the output load.

[0044] The pure output mode is as follows: the first MOS transistor Q1, the second MOS transistor Q2, the third MOS transistor Q3, and the fourth MOS transistor Q4 are always in the off state, and the fifth MOS transistor Q5 and the sixth MOS transistor Q6 are always in the on state, keeping the photovoltaic panel direct-through circuit open and the main circuit off.

[0045] The pure charging mode is as follows: turn off the fourth MOS transistor Q4, adjust the duty cycles of the first MOS transistor Q1, the second MOS transistor Q2, and the third MOS transistor Q3 to track MPPT (maximum power point tracking). For example, when the voltage of the photovoltaic panel is greater than the voltage of the battery and in the buck state, control the conduction time of the first MOS transistor Q1. Taking 100K as an example, if the duty cycle calculated by MPPT is 0.3, then within a carrier period of 10 us, the conduction time of the first MOS transistor Q1 is 3 us. After the first MOS transistor Q1 is turned off, the second MOS transistor Q2 conducts, and the conduction time of Q2 is 7 us, so that the first MOS transistor Q1 and the second MOS transistor Q2 conduct complementarily.

[0046] The charging-while-outputting / discharging-while-outputting mode is as follows: The fifth MOS transistor Q5 and the sixth MOS transistor Q6 are always in the off state. First, adjust the duty cycles of the first MOS transistor Q1, the second MOS transistor Q2, and the third MOS transistor Q3 to enable the battery to operate stably. Then, adjust the duty cycle of the fourth MOS transistor Q4 to enable the micro-inverter to operate stably. Then, adjust the duty cycles of the first MOS transistor Q1, the second MOS transistor Q2, and the third MOS transistor Q3 to track the MPPT.

[0047] When the input power Pin of the photovoltaic panel is greater than the power Pout output to the micro-inverter, it is charging-while-outputting. Since the weakening of the light intensity causes Pin to become smaller, resulting in Pin < Pout, the working mode switches from charging-while-outputting to discharging-while-outputting mode; when the input power Pin of the photovoltaic panel is less than the power Pout output to the micro-inverter, it is discharging-while-outputting mode. Since the strengthening of the light intensity causes Pin to become larger, so that Pin > Pout, the working mode is switched from discharging-while-outputting mode to charging-while-outputting mode.

[0048] When the battery charge reaches the maximum charge threshold, if the working mode is still in the pure charging mode at this time, it is necessary to turn off the first MOS transistor Q1, the second MOS transistor Q2, and the third MOS transistor Q3 to stop working; if it is in the charging-while-outputting mode at this time, then adjust the duty cycles of the first MOS transistor Q1, the second MOS transistor Q2, and the third MOS transistor Q3 to limit the PV input power so that Pin ≤ Pout.

[0049] When the battery charge reaches the minimum discharge threshold, if the working mode is in the pure discharging mode at this time, turn off the fourth MOS transistor Q4 to stop working; if it is in the discharging-while-outputting mode at this time, turn off the fourth MOS transistor Q4 to stop the battery discharge, and then turn on the fifth MOS transistor Q5 and the sixth MOS transistor Q6 to enter the pure output mode.

[0050] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claimed rights.

Claims

1. A control method for a photovoltaic storage topology, characterized in that: Including: Collect the input and output parameters of the photovoltaic and energy storage topology circuit and the battery parameters, perform voltage conversion through an integrated operational amplifier and then perform A / D conversion to obtain AD sampling values every 1ms, calculate the input power Pin, and obtain the target output power Pout through an external signal instruction; Before the photovoltaic and energy storage system is turned on, perform self-check on the photovoltaic and energy storage topology circuit; During self-check, first, based on the battery parameters, determine whether there is a battery in the photovoltaic and energy storage topology circuit. If there is no battery, further determine whether there is a micro-inverter in the photovoltaic and energy storage topology circuit. If there is a micro-inverter, the photovoltaic and energy storage topology circuit enters the pure output mode. If there is no micro-inverter, turn off the bypass and perform self-check again; if there is a battery, switch the working mode according to the input power and the target output power of the photovoltaic and energy storage topology circuit.

2. The control method of a photovoltaic storage topology according to claim 1, characterized in that: Including, if there is no battery, open the photovoltaic panel direct connection loop, wait for Ns, and determine whether there is a micro-inverter according to whether there is current output.

3. The control method of a photovoltaic storage topology according to claim 2, characterized in that: The photovoltaic panel direct connection loop includes a fifth MOS transistor and a sixth MOS transistor. The drain of the fifth MOS transistor is electrically connected to the positive pole of the photovoltaic panel. The source of the fifth MOS transistor is electrically connected to the source of the sixth MOS transistor. The drain of the sixth MOS transistor is connected to the output load.

4. The control method of a photovoltaic storage topology according to claim 3, characterized in that: If there is no battery and no micro-inverter, close the photovoltaic panel direct connection loop, prompt that the starting condition is not met, and perform self-check again.

5. The control method of a photovoltaic storage topology according to claim 4, characterized in that: If there is no battery but there is a micro-inverter, enter the pure output mode. In the photovoltaic and energy storage topology circuit, turn on the fifth MOS transistor and the sixth MOS transistor, turn off other MOS transistors, and the photovoltaic panel is connected to the micro-inverter through the photovoltaic panel direct connection loop.

6. The control method of a photovoltaic storage topology according to claim 5, characterized in that: If there is a battery, further determine whether the voltage of the photovoltaic panel is normal. If the voltage of the photovoltaic panel is not normal, turn on the Buck circuit to control the output voltage, wait for Ns, and determine whether there is a micro-inverter according to whether there is current output. If there is current output, there is a micro-inverter, and enter the pure discharge mode where the battery discharges the micro-inverter; if there is no current output, there is no micro-inverter, prompt that the starting condition is not met, and perform self-check again.

7. The control method of a photovoltaic storage topology according to claim 6, characterized in that: If there is a battery and the voltage of the photovoltaic panel is normal, turn on the Buck-Boost circuit to control the battery voltage. After the battery operates stably, turn on the Buck circuit transistor to control the output voltage, wait for Ns, and determine whether there is a micro-inverter according to whether there is current output.

8. The control method of a photovoltaic storage topology according to claim 7, characterized in that: If the voltage of the photovoltaic panel is normal but there is no micro-inverter, the photovoltaic and energy storage topology circuit enters the pure charging mode, and the photovoltaic panel charges the battery.

9. The control method of a photovoltaic storage topology according to claim 8, characterized in that: If the voltage of the photovoltaic panel is normal and there is a micro-inverter, compare the magnitudes of Pin and Pout. If Pin > Pout, enter the mode of charging while outputting; if Pin < Pout, enter the mode of discharging while outputting; When in the mode of charging while outputting, due to the weakening of the light intensity, Pin becomes smaller, making Pin < Pout, and the working mode switches from the mode of charging while outputting to the mode of discharging while outputting; When in the mode of discharging while outputting, due to the enhancement of the light intensity, Pin becomes larger, making Pin > Pout, and the working mode switches from the mode of discharging while outputting to the mode of charging while outputting.

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