Photovoltaic output power control method, light storage system and storage medium

Abstract

Embodiments of the present application provide a photovoltaic output power control method, a photovoltaic storage system and a storage medium, including: obtaining a plurality of initial photovoltaic voltage given values and at least one initial photovoltaic current given value; comparing and screening the plurality of initial photovoltaic voltage given values and performing voltage loop control to obtain a first photovoltaic current given value; comparing and screening the first photovoltaic current given value and the at least one initial photovoltaic current given value and performing current loop control to obtain a target duty cycle; and controlling photovoltaic output power of a photovoltaic part according to the target duty cycle. Embodiments of the present application adopt a control strategy of a current inner loop and a voltage outer loop, consider and fuse a plurality of initial photovoltaic voltage given values under different conditions in the voltage outer loop, and consider and fuse a plurality of photovoltaic current given values under different conditions in the current inner loop, so that the photovoltaic part can also play a role in system stabilization and rapid operation, and thus the photovoltaic storage system control can be more stable and rapid.

Description

Technical Field

[0001] This application relates to the field of power equipment technology, and in particular to a photovoltaic output power control method, a photovoltaic energy storage system, and a storage medium. Background Technology

[0002] In related technologies, for photovoltaic (PV) and energy storage (ESS) systems, the photovoltaic (PV) component, energy storage component, and inverter component are all connected to a DC bus. The various functions of the PV-ESS system and its stable operation under various conditions are achieved through the control of these three components. Currently, the control of the PV component in PV-ESS systems only implements MPPT (Maximum Power Point Tracking), while delegating the need for stable and rapid system operation entirely to the energy storage and inverter components. However, considering the many requirements for stable operation and rapid response, simply implementing MPPT in the PV component is often insufficient. Summary of the Invention

[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a photovoltaic output power control method, a photovoltaic-energy storage system, and a storage medium, aiming to make the control of the photovoltaic-energy storage system more stable and faster.

[0004] In a first aspect, embodiments of this application provide a photovoltaic output power control method applied to a photovoltaic-storage system. The photovoltaic-storage system includes a photovoltaic component, an energy storage component, and an inverter component. Both the photovoltaic component and the energy storage component are connected to the input terminal of the inverter component via a DC bus. The output terminal of the inverter component is connected to the power grid. The method includes:

[0005] Obtain multiple initial photovoltaic voltage setpoints and at least one initial photovoltaic current setpoint;

[0006] By comparing and filtering multiple initial photovoltaic voltage setpoints and performing voltage loop control, a first photovoltaic current setpoint is obtained;

[0007] The first photovoltaic current setpoint and at least one of the initial photovoltaic current setpoints are compared, filtered, and current loop controlled to obtain the target duty cycle;

[0008] The photovoltaic output power of the photovoltaic section is controlled according to the target duty cycle.

[0009] According to some embodiments of this application, the step of comparing and filtering multiple initial photovoltaic voltage setpoints and performing voltage loop control to obtain a first photovoltaic current setpoint includes:

[0010] The initial photovoltaic voltage setpoints are compared and selected to obtain the final photovoltaic voltage setpoint.

[0011] The measured value of the photovoltaic voltage of the photovoltaic section is obtained, and the final photovoltaic voltage setpoint and the measured photovoltaic voltage value are input to the voltage loop controller to obtain the first photovoltaic current setpoint.

[0012] According to some embodiments of this application, the step of comparing multiple initial photovoltaic voltage setpoints and filtering to obtain a final photovoltaic voltage setpoint includes:

[0013] The maximum voltage setpoint is selected from the multiple initial photovoltaic voltage setpoints, and the maximum voltage setpoint is used as the final photovoltaic voltage setpoint.

[0014] According to some embodiments of this application, the plurality of initial photovoltaic voltage setpoints are determined through at least two steps:

[0015] The measured values ​​of photovoltaic voltage and photovoltaic current of the photovoltaic section are obtained, and the measured values ​​of photovoltaic voltage and photovoltaic current are processed by maximum power point tracking to obtain the first initial photovoltaic voltage setpoint.

[0016] The grid-connected power setpoint and the measured grid-connected power of the photovoltaic-storage system are obtained, and the grid-connected power setpoint and the measured grid-connected power are input to the power loop controller to obtain the second initial photovoltaic voltage setpoint.

[0017] The equipment temperature of the photovoltaic storage system and the average measured value of the photovoltaic current of the photovoltaic part are obtained. The average setpoint value of the photovoltaic current of the photovoltaic part is determined based on the equipment temperature. The average setpoint value of the photovoltaic current and the average measured value of the photovoltaic current are input to the current loop controller to obtain the third initial photovoltaic voltage setpoint value.

[0018] According to some embodiments of this application, the step of comparing and filtering the first photovoltaic current setpoint and at least one of the initial photovoltaic current setpoints and performing current loop control to obtain the target duty cycle includes:

[0019] The first photovoltaic current setpoint is compared with at least one of the initial photovoltaic current setpoints, and a final photovoltaic current setpoint is obtained by filtering.

[0020] The measured value of the photovoltaic current of the photovoltaic section is obtained, and the final photovoltaic current setpoint and the measured value of the photovoltaic current are input to the current loop controller to obtain the target duty cycle.

[0021] According to some embodiments of this application, the initial photovoltaic current setpoint is determined by at least one of the following steps:

[0022] The given value of the DC bus voltage and the measured value of the first bus voltage are obtained. The second photovoltaic current given value is determined based on the given value of the bus voltage and the measured value of the first bus voltage, wherein the measured value of the first bus voltage is greater than the first preset voltage value.

[0023] The given value of the DC bus voltage and the measured value of the second bus voltage are obtained. The third photovoltaic current given value is determined based on the given value of the bus voltage and the measured value of the second bus voltage, wherein the measured value of the second bus voltage is less than the first preset voltage value.

[0024] The final photovoltaic voltage setpoint and the measured photovoltaic voltage value are obtained. When the measured photovoltaic voltage value is less than the difference between the final photovoltaic voltage setpoint and the preset threshold, the fourth photovoltaic current setpoint is determined based on the final photovoltaic voltage setpoint and the measured photovoltaic voltage value.

[0025] According to some embodiments of this application, when the initial photovoltaic current setpoint includes a second photovoltaic current setpoint, a third photovoltaic current setpoint, and a fourth photovoltaic current setpoint, the step of comparing the first photovoltaic current setpoint with at least one of the initial photovoltaic current setpoints to obtain a final photovoltaic current setpoint includes:

[0026] Select the smaller of the two photovoltaic current values;

[0027] The larger of the first smaller value and the third photovoltaic current given value is selected;

[0028] The second smaller value is selected from the larger value and the fourth photovoltaic current given value;

[0029] The second smaller value is used as the final photovoltaic current setpoint.

[0030] According to some embodiments of this application, the photovoltaic section includes a voltage converter for regulating the photovoltaic output voltage, the voltage converter including a switching transistor; controlling the photovoltaic output power of the photovoltaic section according to the target duty cycle includes:

[0031] The switching state of the switching transistor is controlled according to the target duty cycle to adjust the photovoltaic output power of the photovoltaic section.

[0032] Secondly, embodiments of this application provide a controller, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the photovoltaic output power control method of the first aspect described above when running the computer program.

[0033] Thirdly, embodiments of this application provide a photovoltaic-storage system, including a photovoltaic section, an energy storage section, an inverter section, and a controller as described in the second aspect above. The photovoltaic section and the energy storage section are both connected to the input terminal of the inverter section via a DC bus. The output terminal of the inverter section is used to connect to the power grid. The photovoltaic section includes a voltage converter for regulating the photovoltaic output voltage, and the controller is connected to a switching transistor in the voltage converter.

[0034] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions for performing the photovoltaic output power control method as described in the first aspect above.

[0035] Fifthly, embodiments of this application provide a computer program product, including a computer program or computer instructions, characterized in that the computer program or computer instructions are stored in a computer-readable storage medium, a processor of a computer device reads the computer program or computer instructions from the computer-readable storage medium, and the processor executes the computer program or computer instructions, causing the computer device to perform the photovoltaic output power control method as described in the first aspect above.

[0036] According to the technical solution of the embodiments of this application, at least the following beneficial effects are achieved: First, the embodiments of this application acquire multiple initial photovoltaic voltage setpoints and at least one initial photovoltaic current setpoint; then, the embodiments of this application compare and filter the multiple initial photovoltaic voltage setpoints and perform voltage loop control to obtain a first photovoltaic current setpoint; next, the embodiments of this application compare and filter the first photovoltaic current setpoint and at least one initial photovoltaic current setpoint and perform current loop control to obtain a target duty cycle; finally, the embodiments of this application control the photovoltaic output power of the photovoltaic section according to the target duty cycle. The embodiments of this application adopt a control strategy of an inner current loop and an outer voltage loop. The inner current loop has a fast response, ensuring current quality, while the outer voltage loop indirectly achieves power control, thereby maintaining the stable operation of the system; in addition, the embodiments of this application consider and integrate multiple initial photovoltaic voltage setpoints under different conditions in the outer voltage loop, and simultaneously consider and integrate multiple photovoltaic current setpoints under different conditions in the inner current loop, so that the photovoltaic section can also play a role in the stable and fast operation of the system. Therefore, the embodiments of this application can make the control of the photovoltaic-storage system more stable and faster.

[0037] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0038] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0039] Figure 1 This is a system block diagram of a photoelectric storage system provided in one embodiment of this application;

[0040] Figure 2 This is a flowchart of a photovoltaic output power control method provided in one embodiment of this application;

[0041] Figure 3 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application;

[0042] Figure 4 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application;

[0043] Figure 5 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application;

[0044] Figure 6 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application;

[0045] Figure 7 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application;

[0046] Figure 8 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application;

[0047] Figure 9 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application;

[0048] Figure 10 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application;

[0049] Figure 11 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application;

[0050] Figure 12 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application;

[0051] Figure 13 This is a control block diagram of photovoltaic output power provided in one embodiment of this application;

[0052] Figure 14 This is a selection block diagram of photovoltaic current given according to one embodiment of this application;

[0053] Figure 15 This is a schematic diagram of a controller for performing a photovoltaic output power control method according to an embodiment of this application. Detailed Implementation

[0054] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0055] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0056] In the description of this application, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0057] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0058] In some cases, for photovoltaic (PV) and energy storage (ESS) systems, the photovoltaic (PV) component, energy storage component, and inverter component are all connected to the DC bus. The various functions of the PV-ESS system and its stable operation under various conditions are achieved through the joint control of these three components. Currently, the control of the PV component in PV-ESS systems only implements MPPT (Multi-Level Testing), while delegating the need for stable and rapid system operation entirely to the energy storage and inverter components. However, considering the many requirements for stable operation and rapid response, simply implementing MPPT in the PV component is often insufficient.

[0059] Based on the above, this application proposes a photovoltaic output power control method, a photovoltaic energy storage system, and a storage medium, aiming to make the control of the photovoltaic energy storage system more stable and faster.

[0060] The various embodiments of the optical storage system of this application will be further described below with reference to the accompanying drawings.

[0061] like Figure 1 As shown, Figure 1 This is a system block diagram of an embodiment of the optical storage system provided in this application.

[0062] In one embodiment, the photovoltaic-storage system includes, but is not limited to, a photovoltaic section 100, an energy storage section 200, and an inverter section 300. The photovoltaic section 100 and the energy storage section 200 are both connected to the input terminal of the inverter section 300 via a DC bus, and the output terminal of the inverter section 300 is used to connect to the power grid 600.

[0063] In one embodiment, a local load 400 and an electricity meter 500 may also be provided between the inverter section 300 and the power grid 600.

[0064] In one embodiment, the photovoltaic section 100 includes a voltage converter, such as a DC-DC converter, for regulating the photovoltaic voltage, wherein the voltage converter includes a switching transistor.

[0065] In one embodiment, the energy storage section 200 includes a voltage converter, such as a DC-DC converter, for regulating the energy storage charging and discharging voltage, wherein the voltage converter includes a switching transistor.

[0066] Among them, such as Figure 1 As shown, in P C If P is negligible G =P PV +P ES -P Load In the formula, where P G For grid-connected power, P PV For photovoltaic power, P ES For energy storage charging and discharging power, P Load Power consumption of a local load of 400, P C For capacitor C Bus The capacitor consumes power.

[0067] Based on the hardware structure of the photovoltaic energy storage system in the above embodiments, the following presents various embodiments of the photovoltaic output power control method of this application.

[0068] like Figure 2 As shown, Figure 2 This is a flowchart of a photovoltaic output power control method provided in one embodiment of this application; the photovoltaic output power control method can be applied to the photovoltaic energy storage system of any of the above embodiments, and the photovoltaic output power control method includes, but is not limited to, steps S210, S220, S230 and S240.

[0069] Step S210: Obtain multiple initial photovoltaic voltage setpoints and at least one initial photovoltaic current setpoint;

[0070] Step S220: Compare and filter multiple initial photovoltaic voltage setpoints and perform voltage loop control to obtain the first photovoltaic current setpoint;

[0071] Step S230: Compare and filter the first photovoltaic current setpoint and at least one initial photovoltaic current setpoint, and perform current loop control to obtain the target duty cycle;

[0072] Step S240: Control the photovoltaic output power of the photovoltaic section according to the target duty cycle.

[0073] In one embodiment, firstly, this application embodiment can obtain multiple initial photovoltaic voltage setpoints corresponding to various different situations, then filter the multiple initial photovoltaic voltage setpoints and adjust and control them through the voltage outer loop to output a first photovoltaic current setpoint; in addition, this application embodiment can also obtain at least one initial photovoltaic current setpoint, then filter the initial photovoltaic current setpoint and the first photovoltaic current setpoint, i.e., multiple photovoltaic current setpoints, and adjust and control them through the voltage outer loop to output a target duty cycle; finally, the photovoltaic output power of the photovoltaic section is adjusted according to the target duty cycle.

[0074] It is worth noting that the embodiments of this application adopt a control strategy of an inner current loop and an outer voltage loop. The inner current loop has a fast response, ensuring current quality, while the outer voltage loop indirectly controls the power, thereby maintaining the stable operation of the system. In addition, the embodiments of this application consider and integrate multiple initial photovoltaic voltage setpoints under different conditions in the outer voltage loop, and consider and integrate multiple photovoltaic current setpoints under different conditions in the inner current loop. This enables the photovoltaic part to also play a role in the stable and fast operation of the system. Therefore, the embodiments of this application can make the control of the photovoltaic-storage system more stable and faster.

[0075] It should be noted that the control of the photovoltaic part in the existing photovoltaic energy storage system only realizes MPPT, that is, it only considers the initial photovoltaic voltage setpoint under one condition. However, the embodiment of this application considers and integrates multiple initial photovoltaic voltage setpoints under various conditions in the voltage outer loop, and also considers and integrates multiple photovoltaic current setpoints under various conditions in the current inner loop. Therefore, the photovoltaic part can also undertake more functions of stabilization and rapid response, thereby making the control of the photovoltaic energy storage system more stable and faster.

[0076] In addition, such as Figure 3 As shown, Figure 3 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application; regarding the above step S220, it may include, but is not limited to, steps S310 and S320.

[0077] Step S310: Compare multiple initial photovoltaic voltage setpoints and select the final photovoltaic voltage setpoint.

[0078] Step S320: Obtain the measured value of the photovoltaic voltage of the photovoltaic section, and input the final photovoltaic voltage setpoint and the measured photovoltaic voltage value into the voltage loop controller to obtain the first photovoltaic current setpoint.

[0079] In one embodiment, firstly, the present invention can compare the magnitudes of multiple initial photovoltaic voltage setpoints to select a suitable initial photovoltaic voltage setpoint as the final photovoltaic voltage setpoint; then, the present invention will use the final photovoltaic voltage setpoint and the measured photovoltaic voltage value to obtain a first photovoltaic current setpoint through a voltage loop controller.

[0080] In addition, such as Figure 4 As shown, Figure 4 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application; regarding the above step S310, it may include, but is not limited to, steps S410 and S420.

[0081] Step S410: Select the maximum voltage value from multiple initial photovoltaic voltage values;

[0082] Step S420: Use the maximum given voltage value as the final photovoltaic voltage given value.

[0083] It should be noted that the multiple initial photovoltaic voltages may include at least two of a first initial photovoltaic voltage setpoint, a second initial photovoltaic voltage setpoint, and a third initial photovoltaic voltage setpoint. The steps for obtaining the first, second, and third initial photovoltaic voltage setpoints are as follows: Figures 5 to 7 As shown.

[0084] like Figure 5 As shown, Figure 5 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application; the step of obtaining the first initial photovoltaic voltage setpoint may include, but is not limited to, steps S510 and S520.

[0085] Step S510: Obtain the measured values ​​of photovoltaic voltage and photovoltaic current of the photovoltaic section;

[0086] Step S520: Perform maximum power point tracking processing on the measured values ​​of photovoltaic voltage and photovoltaic current to obtain the first initial photovoltaic voltage setpoint.

[0087] In one embodiment, the primary task of the photovoltaic section is MPPT (Multi-Performance Testing) to utilize the photovoltaic power as much as possible. Therefore, the embodiments of this application can obtain the measured values ​​of photovoltaic voltage and photovoltaic current of the photovoltaic section, and obtain the first initial photovoltaic voltage setpoint through the photovoltaic MPPT algorithm.

[0088] like Figure 6 As shown, Figure 6 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application; the step of obtaining the second initial photovoltaic voltage setpoint may include, but is not limited to, steps S610 and S620.

[0089] Step S610: Obtain the grid-connected power setpoint and the measured grid-connected power of the photovoltaic-storage system;

[0090] Step S620: Input the grid-connected power setpoint and the measured grid-connected power to the power loop controller to obtain the second initial photovoltaic voltage setpoint.

[0091] In one embodiment, under certain special circumstances, when the inverter needs to limit power due to grid requirements, such as over-frequency load reduction or anti-reverse current, and the energy storage part cannot fully absorb the photovoltaic power, the photovoltaic needs to be curtailed. That is, in this embodiment, the grid-connected power setpoint and the actual grid-connected power of the photovoltaic-storage system will be obtained, and the second initial photovoltaic voltage setpoint will be obtained through the power loop controller.

[0092] like Figure 7 As shown, Figure 7 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application; the step of obtaining the third initial photovoltaic voltage setpoint may include, but is not limited to, steps S710, S720 and S730.

[0093] Step S710: Obtain the average measured values ​​of the equipment temperature and photovoltaic current of the photovoltaic part of the photovoltaic energy storage system.

[0094] Step S720: Determine the average given value of photovoltaic current for the photovoltaic section based on the equipment temperature;

[0095] Step S730: Input the average photovoltaic current setpoint and the average measured photovoltaic current to the current loop controller to obtain the third initial photovoltaic voltage setpoint.

[0096] In one embodiment, in addition to improving the reliability of system operation and the speed of system operation, the photovoltaic part should also undertake some other functions, such as temperature current limiting. Specifically, when the equipment temperature of the photovoltaic energy storage system is detected to be too high, the current setpoint should be reduced. In this embodiment, the average photovoltaic current setpoint value of the photovoltaic part can be determined according to the equipment temperature, and then the average photovoltaic current setpoint value and the average measured photovoltaic current value are used to obtain the third initial photovoltaic voltage setpoint value through the current loop controller.

[0097] The aforementioned device temperature can be either the temperature of the entire device cavity or the temperature of the entire device radiator; this application embodiment does not specifically limit this.

[0098] In addition, such as Figure 8 As shown, Figure 8 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application; regarding the above step S230, it may include, but is not limited to, steps S810 and S820.

[0099] Step S810: Compare the first photovoltaic current setpoint with at least one initial photovoltaic current setpoint, and select the final photovoltaic current setpoint.

[0100] Step S820: Obtain the measured value of the photovoltaic current of the photovoltaic section, input the final photovoltaic current setpoint and the measured value of the photovoltaic current to the current loop controller to obtain the target duty cycle.

[0101] In one embodiment, firstly, the present application embodiment can compare the magnitude of the first photovoltaic current setpoint and at least one initial photovoltaic current setpoint to select a suitable photovoltaic current setpoint as the final photovoltaic current setpoint; then, the present application embodiment will obtain the target duty cycle by passing the final photovoltaic current setpoint and the measured photovoltaic current value through a current loop controller.

[0102] It should be noted that the initial photovoltaic current setpoint may include at least one of a second photovoltaic current setpoint, a third photovoltaic current setpoint, and a fourth photovoltaic current setpoint, wherein the steps for obtaining the second, third, and fourth photovoltaic current setpoints are as follows: Figures 9 to 11 As shown.

[0103] like Figure 9 As shown, Figure 9 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application; the step of obtaining the second photovoltaic current setpoint may include, but is not limited to, steps S910 and S920.

[0104] Step S910: Obtain the given value of the DC bus voltage and the measured value of the first bus voltage;

[0105] Step S920: Determine the second photovoltaic current setpoint based on the given bus voltage and the measured first bus voltage, wherein the measured first bus voltage is greater than the first preset voltage value.

[0106] In one embodiment, in order to improve the reliability and response speed of the system operation, a bus overvoltage curtailment function is added. This function enables rapid curtailment of solar power when the bus voltage is too high, avoiding bus overvoltage faults during power surges. The second photovoltaic current setpoint is obtained through this function.

[0107] Specifically, the bus overvoltage curtailment is based on the bus voltage setpoint and the measured value of the first bus voltage, and the second photovoltaic current setpoint is obtained when the measured value of the first bus voltage is too high.

[0108] It is understood that the aforementioned first preset voltage value can be pre-set, and this application embodiment does not specifically limit the first preset voltage value.

[0109] like Figure 10 As shown, Figure 10 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application; the step of obtaining the third photovoltaic current setpoint may include, but is not limited to, steps S1010 and S1020.

[0110] Step S1010: Obtain the given value of the DC bus voltage and the measured value of the second bus voltage;

[0111] Step S1020: Determine the third photovoltaic current setpoint based on the given bus voltage and the measured second bus voltage, wherein the measured second bus voltage is less than the first preset voltage value.

[0112] In one embodiment, when the bus voltage is low, the photovoltaic system needs to quickly provide power to compensate for the bus voltage, thus adding a bus undervoltage rapid power compensation function, through which a third photovoltaic current setpoint is obtained.

[0113] Specifically, during the rapid power replenishment for undervoltage at the bus, the third photovoltaic current is determined based on the given bus voltage and the measured second bus voltage, when the measured second bus voltage is lower.

[0114] like Figure 11 As shown, Figure 11 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application; the step of obtaining the third photovoltaic current setpoint may include, but is not limited to, steps S1110 and S1120.

[0115] Step S1110: Obtain the final photovoltaic voltage setpoint and the measured photovoltaic voltage value for the photovoltaic section;

[0116] Step S1120: When the measured value of photovoltaic voltage is less than the difference between the final photovoltaic voltage setpoint and the preset threshold, the fourth photovoltaic current setpoint is determined based on the final photovoltaic voltage setpoint and the measured photovoltaic voltage.

[0117] In one embodiment, after enabling the aforementioned bus undervoltage rapid power compensation function, due to the power characteristics of the photovoltaic panel, increasing the photovoltaic current may not necessarily increase the photovoltaic power. If no limit is added, it may further reduce the power input on the bus, exacerbating the bus undervoltage situation. Therefore, a photovoltaic undervoltage current limit is added. When the actual photovoltaic voltage is lower than the difference between the photovoltaic voltage setpoint and the preset threshold, the photovoltaic current setpoint is limited, and a fourth photovoltaic current setpoint value is obtained through this function.

[0118] Specifically, the photovoltaic undervoltage current limiting is a fourth photovoltaic current setpoint obtained when the measured photovoltaic voltage is lower than the final photovoltaic voltage setpoint and the measured photovoltaic voltage.

[0119] In addition, such as Figure 12 As shown, Figure 12 This is a flowchart of a photovoltaic output power control method provided in another embodiment of this application; when the initial photovoltaic current setpoint includes a second photovoltaic current setpoint, a third photovoltaic current setpoint, and a fourth photovoltaic current setpoint, the above step S810 may include, but is not limited to, steps S1210, S1220, S1230, and S1240.

[0120] Step S1210: Select the smaller value between the first photovoltaic current setpoint and the second photovoltaic current setpoint;

[0121] Step S1220: Select the larger value from the first smaller value and the third photovoltaic current given value;

[0122] Step S1230: Select the second smallest value from the larger value and the fourth photovoltaic current given value;

[0123] Step S1240: Use the second smaller value as the final photovoltaic current setpoint.

[0124] In one embodiment, a first smaller value is selected from the first photovoltaic current setpoint obtained from the voltage loop controller and the second photovoltaic current setpoint obtained from the bus overvoltage curtailment. Then, the first smaller value is compared with the third photovoltaic current setpoint obtained from the bus undervoltage rapid power replenishment, and the larger value is selected. Then, the larger value is compared with the fourth photovoltaic current setpoint obtained from the photovoltaic undervoltage current limiting, and the second smaller value is selected. The second smaller value is then the final photovoltaic current setpoint.

[0125] In one embodiment, step S240 can be: controlling the switching state of the switching transistor according to the target duty cycle to adjust the photovoltaic output power of the photovoltaic section.

[0126] Based on the photovoltaic output power control methods of the above embodiments, the overall embodiments of the photovoltaic output power control method of this application are presented below.

[0127] In one embodiment, such as Figure 1 As shown, in a photovoltaic-storage system, the photovoltaic component, energy storage component, and inverter component are all connected to the DC bus. Through the control of these three components, the various functions of the photovoltaic-storage system and its stable operation under various conditions are realized.

[0128] In addition, such as Figure 13 As shown, Figure 13 This is a control block diagram of photovoltaic output power provided in one embodiment of this application. Wherein, Vpv* refers to the final photovoltaic voltage setpoint; Vpv refers to the measured photovoltaic voltage; Ipv* refers to the final photovoltaic current setpoint; Ipv refers to the measured photovoltaic current; Pg* refers to the grid-connected power setpoint; Pg refers to the measured grid-connected power; Ig* refers to the average photovoltaic current setpoint; Ig refers to the average measured photovoltaic current; and D is the target duty cycle.

[0129] The primary task of the photovoltaic section is MPPT (Multi-Performance Testing), which utilizes the photovoltaic power as much as possible. The initial photovoltaic voltage setpoint can be obtained through the photovoltaic MPPT algorithm.

[0130] In some special cases, when the inverter needs to limit power due to grid requirements, such as over-frequency load reduction or reverse current prevention, and the energy storage part cannot fully absorb the photovoltaic power, the photovoltaic needs to be curtailed. That is, the target power of the photovoltaic is obtained according to the system's needs, and the second initial photovoltaic voltage setpoint is obtained through the power loop controller.

[0131] In addition to improving system reliability and response speed, the photovoltaic module should also perform other functions. For example, temperature-controlled current limiting: when the cavity temperature or heat sink temperature is detected to be too high, the current setpoint should be reduced, and the resulting current setpoint is used to obtain the third initial photovoltaic voltage setpoint through the current loop controller.

[0132] The MPPT, curtailment, and temperature-based current limiting functions each yield an initial photovoltaic voltage setpoint. These three initial photovoltaic voltage setpoints are then used to select the final photovoltaic voltage setpoint. Since these three functions have relatively low requirements for response speed, their control is placed in the outer loop, and the resulting output is the final photovoltaic voltage setpoint. The voltage setpoint selection can be simplified to taking the maximum value among the three.

[0133] In this embodiment of the application, after obtaining the final photovoltaic voltage setpoint, the first photovoltaic current setpoint is obtained through the voltage loop controller.

[0134] In addition, to improve the reliability and response speed of the system, a bus overvoltage curtailment function has been added. This function enables rapid curtailment of solar power when the bus voltage is too high, avoiding bus overvoltage faults during power surges. The second photovoltaic current setpoint is obtained through this function.

[0135] When the bus voltage is low, the photovoltaic system needs to quickly provide power to compensate for the bus voltage. This adds a bus undervoltage fast power compensation function, through which a third photovoltaic current setpoint is obtained.

[0136] After enabling the aforementioned bus undervoltage rapid power compensation function, due to the power characteristics of the photovoltaic panels, increasing the photovoltaic current may not necessarily increase the photovoltaic power. If no limit is added, it may further reduce the power input on the bus, exacerbating the bus undervoltage situation. Therefore, photovoltaic undervoltage current limiting is added. When the actual photovoltaic voltage is lower than the photovoltaic voltage setpoint minus a threshold, the photovoltaic current setpoint is limited, and a fourth photovoltaic current setpoint value is obtained through this function.

[0137] The voltage loop control, bus overvoltage curtailment, bus undervoltage rapid power replenishment, and photovoltaic undervoltage current limiting each generate a photovoltaic current setpoint. These four photovoltaic current setpoints are then selected to obtain the final photovoltaic current setpoint. Since these four functions have high requirements for response speed, their control is placed in the inner loop.

[0138] The final photovoltaic current setpoint is used to obtain the final target duty cycle through the current loop, which controls the operation of the DC-DC converter in the photovoltaic section.

[0139] The specific scheme for selecting the above current setting is as follows: Figure 14 As shown, the smaller of the first photovoltaic current setpoint obtained from the voltage loop controller and the second photovoltaic current setpoint obtained from the bus overvoltage curtailment is selected. The selected result is compared with the third photovoltaic current setpoint obtained from the bus undervoltage rapid power replenishment and the larger one is selected. The selected result is compared with the fourth photovoltaic current setpoint obtained from the photovoltaic undervoltage current limiting and the smaller one is selected.

[0140] Based on the photovoltaic output power control methods of the above embodiments, the following presents various embodiments of the controller, photovoltaic energy storage system, computer-readable storage medium, and computer program product of this application.

[0141] like Figure 15 As shown, Figure 15This is a schematic diagram of a controller for executing a photovoltaic output power control method according to an embodiment of this application. The controller 700 implemented in this application includes: a processor 710, a memory 720, and a computer program stored in the memory 720 and executable on the processor 710, wherein... Figure 15 The example uses a processor 710 and a memory 720.

[0142] The processor 710 and memory 720 can be connected via a bus or other means. Figure 15 Taking the example of a connection between China and Israel via a bus.

[0143] Memory 720, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory 720 may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory 720 may optionally include remotely located memories 720 relative to processor 710, which can be connected to controller 700 via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0144] Those skilled in the art will understand that Figure 15 The device structure shown does not constitute a limitation on the controller 700 and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0145] exist Figure 15 In the controller 700 shown, the processor 710 can be used to call the control program stored in the memory 720, thereby implementing the photovoltaic output power control method described above. Specifically, the non-transient software program and instructions required to implement the photovoltaic output power control method of the above embodiment are stored in the memory 720. When executed by the processor 710, the photovoltaic output power control method of the above embodiment is executed.

[0146] It is worth noting that since the controller 700 of this application embodiment can execute the photovoltaic output power control method of any of the above embodiments, the specific implementation method and technical effects of the controller 700 of this application embodiment can refer to the specific implementation method and technical effects of the photovoltaic output power control method of any of the above embodiments.

[0147] Furthermore, one embodiment of this application also provides a photovoltaic-storage system, which includes a photovoltaic section, an energy storage section, an inverter section, and a controller as described in the above embodiment. The photovoltaic section and the energy storage section are both connected to the input terminal of the inverter section via a DC bus. The output terminal of the inverter section is used to connect to the power grid. The photovoltaic section includes a voltage converter for regulating the photovoltaic output voltage, and the controller is connected to the switching transistor in the voltage converter.

[0148] It is worth noting that, since the photovoltaic and energy storage system of this application includes the controller of the above embodiments, and the controller of the above embodiments is capable of executing the photovoltaic output power control method of any of the above embodiments, the specific implementation method and technical effects of the photovoltaic and energy storage system of this application can be referred to the specific implementation method and technical effects of the photovoltaic output power control method of any of the above embodiments.

[0149] Furthermore, one embodiment of this application provides a computer-readable storage medium storing computer-executable instructions for performing the aforementioned photovoltaic output power control method. Exemplarily, the above-described method is executed... Figures 2 to 12 The methods and steps in the text.

[0150] It is worth noting that, since the computer-readable storage medium of this application embodiment can execute the photovoltaic output power control method of any of the above embodiments, the specific implementation and technical effects of the computer-readable storage medium of this application embodiment can be referred to the specific implementation and technical effects of the photovoltaic output power control method of any of the above embodiments.

[0151] Furthermore, one embodiment of this application also provides a computer program product, including a computer program or computer instructions, which are stored in a computer-readable storage medium. A processor of a computer device reads the computer program or computer instructions from the computer-readable storage medium and executes the computer program or computer instructions, causing the computer device to perform the photovoltaic output power control method described above. Exemplarily, the above-described method is executed... Figures 2 to 12 The methods and steps in the text.

[0152] It is worth noting that, since the computer program product of this application embodiment can execute the photovoltaic output power control method of any of the above embodiments, the specific implementation method and technical effect of the computer program product of this application embodiment can refer to the specific implementation method and technical effect of the photovoltaic output power control method of any of the above embodiments.

[0153] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically include computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0154] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0155] In the several embodiments provided in this application, it should be understood that the disclosed systems, instruments, and methods can be implemented in other ways. For example, the instrument embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between instruments or units may be electrical, mechanical, or other forms. Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, i.e., they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0156] It should also be understood that the various implementation methods provided in this application can be combined arbitrarily to achieve different technical effects.

[0157] The above provides a detailed description of the preferred embodiments of this application. However, this application is not limited to the above-described embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A photovoltaic output power control method, characterized in that, The method is applied to a photovoltaic-storage system, which includes a photovoltaic component, an energy storage component, and an inverter component. The photovoltaic component and the energy storage component are both connected to the input terminal of the inverter component via a DC bus, and the output terminal of the inverter component is connected to the power grid. Obtain multiple initial photovoltaic voltage setpoints and at least one initial photovoltaic current setpoint; By comparing and filtering multiple initial photovoltaic voltage setpoints and performing voltage loop control, a first photovoltaic current setpoint is obtained; The first photovoltaic current setpoint and at least one of the initial photovoltaic current setpoints are compared, filtered, and current loop controlled to obtain the target duty cycle; The photovoltaic output power of the photovoltaic section is controlled according to the target duty cycle.

2. The method according to claim 1, characterized in that, The process of comparing and filtering multiple initial photovoltaic voltage setpoints and performing voltage loop control to obtain a first photovoltaic current setpoint includes: The initial photovoltaic voltage setpoints are compared and selected to obtain the final photovoltaic voltage setpoint. The measured value of the photovoltaic voltage of the photovoltaic section is obtained, and the final photovoltaic voltage setpoint and the measured photovoltaic voltage value are input to the voltage loop controller to obtain the first photovoltaic current setpoint.

3. The method according to claim 2, characterized in that, The step of comparing multiple initial photovoltaic voltage setpoints and selecting the final photovoltaic voltage setpoint includes: The maximum voltage setpoint is selected from the multiple initial photovoltaic voltage setpoints, and the maximum voltage setpoint is used as the final photovoltaic voltage setpoint.

4. The method according to any one of claims 1 to 3, characterized in that, The plurality of said initial photovoltaic voltage setpoints are determined by at least the following two steps: The measured values ​​of photovoltaic voltage and photovoltaic current of the photovoltaic section are obtained, and the measured values ​​of photovoltaic voltage and photovoltaic current are processed by maximum power point tracking to obtain the first initial photovoltaic voltage setpoint. The grid-connected power setpoint and the measured grid-connected power of the photovoltaic-storage system are obtained, and the grid-connected power setpoint and the measured grid-connected power are input to the power loop controller to obtain the second initial photovoltaic voltage setpoint. The equipment temperature of the photovoltaic storage system and the average measured value of the photovoltaic current of the photovoltaic part are obtained. The average setpoint value of the photovoltaic current of the photovoltaic part is determined based on the equipment temperature. The average setpoint value of the photovoltaic current and the average measured value of the photovoltaic current are input to the current loop controller to obtain the third initial photovoltaic voltage setpoint value.

5. The method according to claim 1, characterized in that, The step of comparing and filtering the first photovoltaic current setpoint and at least one of the initial photovoltaic current setpoints, and performing current loop control to obtain the target duty cycle includes: The first photovoltaic current setpoint is compared with at least one of the initial photovoltaic current setpoints, and a final photovoltaic current setpoint is obtained by filtering. The measured value of the photovoltaic current of the photovoltaic section is obtained, and the final photovoltaic current setpoint and the measured value of the photovoltaic current are input to the current loop controller to obtain the target duty cycle.

6. The method according to claim 5, characterized in that, The initial photovoltaic current setpoint is determined through at least one of the following steps: The given value of the DC bus voltage and the measured value of the first bus voltage are obtained. The second photovoltaic current given value is determined based on the given value of the bus voltage and the measured value of the first bus voltage, wherein the measured value of the first bus voltage is greater than the first preset voltage value. The given value of the DC bus voltage and the measured value of the second bus voltage are obtained. The third photovoltaic current given value is determined based on the given value of the bus voltage and the measured value of the second bus voltage, wherein the measured value of the second bus voltage is less than the first preset voltage value. The final photovoltaic voltage setpoint and the measured photovoltaic voltage value are obtained. When the measured photovoltaic voltage value is less than the difference between the final photovoltaic voltage setpoint and the preset threshold, the fourth photovoltaic current setpoint is determined based on the final photovoltaic voltage setpoint and the measured photovoltaic voltage value.

7. The method according to claim 6, characterized in that, When the initial photovoltaic current setpoint includes a second photovoltaic current setpoint, a third photovoltaic current setpoint, and a fourth photovoltaic current setpoint, the step of comparing the first photovoltaic current setpoint with at least one of the initial photovoltaic current setpoints to obtain the final photovoltaic current setpoint includes: Select the smaller of the two photovoltaic current values; The larger of the first smaller value and the third photovoltaic current given value is selected; The second smaller value is selected from the larger value and the fourth photovoltaic current given value; The second smaller value is used as the final photovoltaic current setpoint.

8. The method according to claim 1, characterized in that, The photovoltaic section includes a voltage converter for regulating the photovoltaic output voltage, the voltage converter including a switching transistor; controlling the photovoltaic output power of the photovoltaic section according to the target duty cycle includes: The switching state of the switching transistor is controlled according to the target duty cycle to adjust the photovoltaic output power of the photovoltaic section.

9. A controller, characterized in that, include: The device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the photovoltaic output power control method as described in any one of claims 1 to 8 when running the computer program.

10. A photovoltaic energy storage system, characterized in that, The photovoltaic-storage system includes a photovoltaic section, an energy storage section, an inverter section, and a controller as described in claim 9. The photovoltaic section and the energy storage section are both connected to the input terminal of the inverter section via a DC bus. The output terminal of the inverter section is used to connect to the power grid. The photovoltaic section includes a voltage converter for regulating the photovoltaic output voltage. The controller is connected to the switching transistor in the voltage converter.

11. A computer-readable storage medium, characterized in that: The device stores computer-executable instructions for performing the photovoltaic output power control method as described in any one of claims 1 to 8.

12. A computer program product, comprising a computer program or computer instructions, characterized in that, The computer program or the computer instructions are stored in a computer-readable storage medium. The processor of the computer device reads the computer program or the computer instructions from the computer-readable storage medium and executes the computer program or the computer instructions, causing the computer device to perform the photovoltaic output power control method as described in any one of claims 1 to 8.

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