Inverter control method, control device and optical storage system

Abstract

The invention discloses a control method and a control device of an inverter and a light storage system, and belongs to the field of photovoltaic technology. The method comprises the following steps: acquiring the current grid-connected point power of the grid-connected point, and determining the first output power of the inverter by taking the target grid-connected point power as a reference value based on the current grid-connected point power; the current charge state of the energy storage device is acquired, the second output power of the inverter is determined based on the current charge state by taking a target charge state as a reference value, and the target charge state is determined based on the current charge state; determining the target output power of the inverter based on the first output power, the second output power and the rated output power of the inverter; and controlling the output power of the inverter by taking the target output power as a reference value. According to the method, the passive light abandoning behavior of the light storage system in the high-irradiation period can be reduced, and the energy storage device can fully absorb photovoltaic energy.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic technology, and in particular relates to a control method, control device and photovoltaic energy storage system for an inverter. Background Technology

[0002] The actual output power of a photovoltaic (PV) string is positively correlated with irradiance. During periods of low irradiance, the actual output power of the PV string is often lower than its maximum output power. Generally, the maximum output power of the strings in the system is configured to be about 1.5 times the rated power of the inverter. By over-configuring, the high-power generation period of the day is extended, thereby increasing the power generation of the PV-storage system and obtaining higher power generation revenue.

[0003] However, traditional control strategies prioritize charging the energy storage batteries during periods of low irradiance. During periods of high irradiance, the system cannot fully convert the excess power generated by the photovoltaic strings due to the inverter's rated power limitation. Simultaneously, because the energy storage batteries are already fully charged, the system cannot absorb excess photovoltaic energy, resulting in passive curtailment of solar power during high irradiance periods. This wastes photovoltaic energy and reduces the system's power generation revenue. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a control method, control device, and photovoltaic energy storage system for an inverter, which can reduce the waste of photovoltaic energy and improve the power generation revenue of the system.

[0005] In a first aspect, this application provides a control method for an inverter, wherein the DC terminal of the inverter is connected to a photovoltaic power generation device and an energy storage device respectively via a DC bus, and the AC terminal of the inverter is connected to an electrical load at a grid connection point, the method comprising: Obtain the current grid connection power of the grid connection point, and based on the current grid connection power, with the target grid connection power as a reference value, determine the first output power of the inverter; The current state of charge of the energy storage device is obtained, and based on the current state of charge and with a target state of charge as a reference, the second output power of the inverter is determined, wherein the target state of charge is determined based on the current state of charge. Based on the first output power, the second output power, and the rated output power of the inverter, determine the target output power of the inverter; The output power of the inverter is controlled using the target output power as a reference value.

[0006] According to the inverter control method of this application, the first output power is calculated with grid connection point power control as the target, the second output power is calculated with state of charge control as the target, and the target output power for inverter output power control is determined by combining the rated output power of the inverter. This can reduce the passive curtailment of photovoltaic energy storage system during high irradiance periods, enable energy storage device to fully absorb photovoltaic energy, and effectively improve energy utilization and system power generation revenue.

[0007] According to one embodiment of this application, the target state of charge is set to the current state of charge when preset conditions are met.

[0008] According to one embodiment of this application, the preset condition is that the change in the state of charge of the energy storage device reaches a preset threshold.

[0009] According to one embodiment of this application, determining the target output power of the inverter based on the first output power, the second output power, and the rated output power of the inverter includes: With the second output power as the lower limit and the rated output power as the upper limit, the first output power, the second output power, and the rated output power are compared, and the target output power is determined based on the comparison result.

[0010] According to one embodiment of this application, comparing the first output power, the second output power, and the rated output power, and determining the target output power based on the comparison result, includes: Application formula

[0011] Determine the target output power; in, The target output power, The rated output power, The first output power, This is the second output power.

[0012] According to one embodiment of this application, determining the target output power of the inverter based on the first output power, the second output power, and the rated output power of the inverter includes: When the current power generation of the photovoltaic power generation device is greater than the rated output power, in response to the second output power being greater than the rated output power, the target output power is determined to be equal to the rated output power, the charging and discharging power of the energy storage device is greater than 0, and the charging and discharging power of the energy storage device is determined based on the current power generation and the rated output power.

[0013] According to one embodiment of this application, determining the target output power of the inverter based on the first output power, the second output power, and the rated output power of the inverter includes: If the current power generation of the photovoltaic power generation device is less than or equal to the rated output power, in response to the second output power being greater than the first output power, the target output power is determined to be equal to the second output power, wherein the second output power is determined based on the current power generation.

[0014] According to one embodiment of this application, the target grid connection point power is 0.

[0015] Secondly, this application provides a control device for an inverter, wherein the DC terminal of the inverter is connected to a photovoltaic power generation device and an energy storage device respectively via a DC bus, and the AC terminal of the inverter is connected to the electrical load at a grid connection point. The control device includes: The first processing module is used to obtain the current grid connection point power of the grid connection point, and based on the current grid connection point power, with the target grid connection point power as a reference value, determine the first output power of the inverter; The second processing module is used to obtain the current state of charge of the energy storage device, and based on the current state of charge, with the target state of charge as a reference value, determine the second output power of the inverter, wherein the target state of charge is determined based on the current state of charge. The third processing module is used to determine the target output power of the inverter based on the first output power, the second output power and the rated output power of the inverter; The fourth processing module is used to control the output power of the inverter with the target output power as a reference value.

[0016] Thirdly, this application provides an optical storage system, comprising: Photovoltaic power generation devices, energy storage devices, and inverters; The inverter's DC terminal is connected to the photovoltaic power generation device and the energy storage device via a DC bus, and the inverter's AC terminal is connected to the electrical load at the grid connection point. The photovoltaic-energy storage system also includes the inverter control device as described in the second aspect above.

[0017] 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

[0018] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the structure of the photovoltaic energy storage system provided in the embodiments of this application; Figure 2 This is a flowchart illustrating the control method for an inverter provided in an embodiment of this application; Figure 3 This is a schematic diagram of the first output power determination process provided in an embodiment of this application; Figure 4 This is a schematic diagram of the second output power determination process provided in an embodiment of this application; Figure 5 This is a schematic diagram of the target output power determination process provided in the embodiments of this application; Figure 6 This is a schematic diagram of the control device for the inverter provided in the embodiments of this application.

[0019] Figure label: Inverter 110, photovoltaic power generation device 120, energy storage device 130, electrical load 140, DC bus 150, first DC converter 161, second DC converter 162, power sensor 170, power grid 180. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0021] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0022] The control method of inverter 110, the control device of inverter 110, and the photovoltaic-storage system provided in this application will be described in detail below with reference to the accompanying drawings and through specific embodiments and application scenarios.

[0023] The control method of inverter 110 can be applied to inverter 110 in photovoltaic energy storage system, and can be executed by hardware or software in inverter 110.

[0024] like Figure 1 As shown, the photovoltaic-storage system includes a photovoltaic power generation device 120, an energy storage device 130, and an inverter 110. The DC terminal of the inverter 110 is connected to the photovoltaic power generation device 120 and the energy storage device 130 respectively via a DC bus 150. The AC terminal of the inverter 110 is connected to the grid connection point of the electrical load 140.

[0025] Inverter 110 is connected to first DC converter 161 via DC bus 150. First DC converter 161 can transfer the photovoltaic power generation of photovoltaic power generation device 120 to DC bus 150 and stabilize the voltage of DC bus 150.

[0026] Inverter 110 is connected to second DC converter 162 via DC bus 150. Second DC converter 162 can transfer energy from DC bus 150 to energy storage device 130 or transfer energy from energy storage device 130 to DC bus 150 and stabilize the voltage of DC bus 150.

[0027] The AC terminal of the inverter 110 is connected to the grid connection point of the electrical load 140. The inverter 110 can transfer the energy on the DC bus 150 to the electrical load 140 or the power grid 180. A power sensor 170 can be set at the grid connection point to collect the power information (e.g., active power at the grid connection point) in real time.

[0028] It is understandable that the first DC converter 161, the second DC converter 162 and the inverter 110 are coupled together by the DC bus 150. The photovoltaic-storage system is a DC-coupled system. The photovoltaic power generation of the photovoltaic power generation device 120 can supply the energy storage device 130, the electrical load 140 and the power grid 180.

[0029] In actual implementation, the first DC converter 161, the second DC converter 162, the inverter 110, and the energy storage device 130 can be components of the photovoltaic-energy storage integrated machine. The power sensor 170 can establish communication with the photovoltaic-energy storage integrated machine and can transmit the active power at the grid connection point to the photovoltaic-energy storage integrated machine for the control of the first DC converter 161, the second DC converter 162, and the inverter 110.

[0030] It is understandable that the power output of the photovoltaic power generation device 120 is positively correlated with the irradiance. For example, during periods of low irradiance such as morning and evening, the actual power output of the photovoltaic power generation device 120 will be lower than its rated output power.

[0031] In related technologies, to enable the system to output more photovoltaic power during periods of low irradiance, the maximum output power of the photovoltaic strings is configured to be approximately 1.5 times the rated power of the inverter. This over-sizing extends the high-power generation period each day, thereby increasing the system's power generation. However, current control strategies prioritize charging the energy storage batteries during periods of low irradiance. Once the high irradiance period begins, the inverter, limited by its rated power, cannot fully convert the excess power generated by the photovoltaic strings. Simultaneously, because the energy storage batteries are already fully charged, the system cannot absorb excess photovoltaic energy, leading to passive curtailment and wasted photovoltaic energy, thus reducing the system's power generation revenue.

[0032] This application provides a control method for an inverter 110, which can reduce the passive curtailment of photovoltaic energy storage systems during periods of high irradiance, enabling the energy storage device 130 to fully absorb photovoltaic energy and effectively improve energy utilization and system power generation revenue.

[0033] like Figure 2 As shown, the control method of the inverter 110 includes steps 210, 220, 230 and 240.

[0034] Step 210: Obtain the current grid connection point power and, based on the current grid connection point power and with the target grid connection point power as a reference value, determine the first output power of inverter 110.

[0035] It is understandable that the current grid connection point power refers to the real-time active power of the grid connection point, which can be collected in real time by the power sensor 170 set at the grid connection point.

[0036] In this step, the control target is the grid connection point power. The current grid connection point power collected in real time is used as the feedback value, and the preset target grid connection point power is used as the reference value to calculate the first output power for adjusting the power output of inverter 110.

[0037] In actual implementation, a grid connection point power control module can be designed. The grid connection point power control module calculates the first output power according to closed-loop control logic, using the current grid connection point power as the feedback value and the target grid connection point power as the reference value.

[0038] In some embodiments, the target grid connection point power is 0.

[0039] In this embodiment, setting the target grid connection point power to 0 can prevent the photovoltaic-storage system from purchasing electricity from the grid 180 to supply the load 140. In the photovoltaic-storage system, the photovoltaic power generation device 120 and the energy storage device 130 supply electricity to the load 140. It can also allow excess photovoltaic power to be fed back to the grid 180 to obtain revenue from selling electricity.

[0040] In actual implementation, for the grid connection point power control module, if the current grid connection point power is less than 0, the power output of inverter 110 needs to be increased, and the first output power increases. If the current grid connection point power is greater than 0, the power output of inverter 110 needs to be decreased, and the first output power decreases.

[0041] In this embodiment, based on the current grid connection point power and with the target grid connection point power as a reference value, the first output power can be calculated using a P (proportional) control algorithm, a PI (proportional-integral) control algorithm, or a PID (proportional-integral-derivative) control algorithm.

[0042] For example, such as Figure 3 As shown, the power sensor 170 at the grid connection point collects the current grid connection point power in real time. Target grid connection power =0, the grid-connected power control module can be a P regulator, PI regulator, or PID regulator, based on ,by =0 is used as a reference value to obtain the first output power. .

[0043] Step 220: Obtain the current state of charge of the energy storage device 130, and based on the current state of charge, with the target state of charge as a reference value, determine the second output power of the inverter 110.

[0044] In this step, the control target is the state of charge of the energy storage device 130. The real-time current state of charge of the energy storage device 130 is used as the feedback value, and the preset target state of charge is used as the reference value to determine the second output power for adjusting the power output of the inverter 110.

[0045] In practical implementation, an energy storage state of charge control module can be designed. The energy storage state of charge control module calculates the second output power according to the closed-loop control logic, using the real-time current state of charge of the energy storage device 130 as the feedback value and the preset target state of charge as the reference value.

[0046] The target state of charge is determined based on the current state of charge.

[0047] It should be noted that the current state of charge of the energy storage device 130 is related to whether the energy storage device 130 is in a charging state. If the energy storage device 130 is in a charging state, the current state of charge of the energy storage device 130 increases. If the energy storage device 130 is not in a charging state, the current state of charge of the energy storage device 130 remains unchanged or decreases.

[0048] In this embodiment, a target state of charge is set according to the current state of charge. When the current state of charge changes, the target state of charge can change accordingly. For the energy storage state of charge control module, when the real-time current state of charge of the energy storage device 130 increases, the power output of the inverter 110 needs to be increased, and the calculated second output power increases. When the real-time current state of charge of the energy storage device 130 decreases, the power output of the inverter 110 needs to be decreased, and the calculated second output power decreases.

[0049] It should be noted that whether the energy storage device 130 is in a charging state is determined by the power direction of the second DC converter 162 in the photovoltaic energy storage system. The second output power calculated by the energy storage state of charge control module will not directly participate in the control of the charging state of the energy storage device 130.

[0050] In this embodiment, based on the current state of charge and with the target state of charge as a reference value, the second output power can be calculated using a P (proportional) control algorithm, a PI (proportional-integral) control algorithm, or a PID (proportional-integral-derivative) control algorithm.

[0051] For example, such as Figure 4 As shown, the current state of charge of the energy storage device 130 is collected in real time. Set the target state of charge. The energy storage state-of-charge control module can be a P regulator, PI regulator, or PID regulator, based on... ,by Using the reference value, the second output power is obtained. .

[0052] Step 230: Determine the target output power of inverter 110 based on the first output power, the second output power and the rated output power of inverter 110.

[0053] It should be noted that the first output power output by the grid connection point power control module and the second output power output by the energy storage state of charge control module do not directly affect the output power control of the inverter 110. After processing the first output power, the second output power and the rated output power of the inverter 110, the target output power used for the output power control of the inverter 110 is obtained.

[0054] In actual implementation, the target output power can be equal to the first output power, the second output power, or the rated output power.

[0055] In this embodiment, the target grid connection point power is 0, and the control objective of the grid connection point power control module is that the photovoltaic storage system does not purchase power from the grid 180 to supply power to the electrical load 140; the target state of charge is set based on the real-time current state of charge, and the control objective of the energy storage state of charge control module is that the energy storage device 130 absorbs the photovoltaic power generated by the over-sizing of the photovoltaic storage system.

[0056] In this step, a decision is made based on the calculated first and second output powers to determine the target output power for inverter 110 output power control. The target output power is the result of the cooperation and competition between the grid connection point power control module and the energy storage state of charge control module. It satisfies the control objectives of the photovoltaic-storage system not purchasing power from the grid 180 to supply power to the load 140 and the energy storage device 130 absorbing the photovoltaic power generated by the over-sizing of the photovoltaic-storage system. Furthermore, the final target output power is limited by the hardware constraint of the rated output power of inverter 110, which can ensure the normal operation of inverter 110.

[0057] In some embodiments, determining the target output power of inverter 110 based on the first output power, the second output power, and the rated output power of inverter 110 includes: With the second output power as the lower limit and the rated output power as the upper limit, the first output power, the second output power, and the rated output power are compared, and the target output power is determined based on the comparison results.

[0058] In this embodiment, the second output power is used as the lower limit of the inverter 110 output power reference value, and the rated output power is used as the upper limit of the inverter 110 output power reference value. The first output power is used as the input value, and the target output power of the inverter 110 is obtained after being limited by the upper and lower limits of the second output power and the rated output power.

[0059] In actual implementation, the target output power can be equal to the first output power, the second output power, or the rated output power.

[0060] For example, such as Figure 5 As shown, the first output power is calculated and output by the grid connection point power control module. The second output power is calculated and output by the energy storage state of charge control module. With rated output power The upper limit, the second output power As the lower limit, for the first output power Limit the output to achieve the target output power of inverter 110. According to the target output power Control the power output of inverter 110.

[0061] In some embodiments, comparing a first output power, a second output power, and a rated output power, and determining a target output power based on the comparison result, includes: Application formula

[0062] Determine the target output power; in, For the target output power, Rated output power, For the first output power, This is the second output power.

[0063] like The lower limit of the power reference value is greater than or equal to the upper limit of the power reference value, and the target output power is... No longer limited by the energy storage state of charge control module, target output power The value is the upper limit of the power reference value, i.e., the target output power. The value is equal to the rated output power. .

[0064] like , The input is subject to an upper limit of the power reference value. Limitations, target output power The value is equal to the rated output power. .

[0065] like The lower limit of the power reference value is lower than the upper limit of the power reference value, which is normal. This is due to the limitation of the energy storage state of charge control module, which controls the first output power. For input, Second output power greater than or equal to the lower limit of the power reference value Target output power The value is equal to the first output power. .

[0066] like The lower limit of the power reference value is lower than the upper limit of the power reference value, which is normal. Second output power less than or equal to the lower limit of the power reference value , As the lower limit of the input, it is subject to the power reference value. Limitations, target output power The value is equal to the second output power. .

[0067] Step 240: Using the target output power as a reference value, control the output power of inverter 110.

[0068] In this step, the target output power is used as a reference value (also known as a set value), and the real-time output power of the inverter 110 is used as a feedback value. The deviation between the target output power and the real-time output power of the inverter 110 is calculated. The control signal of the inverter 110 is dynamically adjusted according to the deviation to control the output power of the inverter 110 so that the real-time output power of the inverter 110 can quickly and stably follow the target output power.

[0069] It should be noted that the inverter 110 in this embodiment has two control objectives: first, when the photovoltaic power cannot meet the load operation, the energy storage device 130 can be controlled to discharge and supply the electrical load 140, and to purchase less or no electricity from the grid 180 to supply the electrical load 140; second, during periods of high irradiance, the energy storage device 130 can absorb the photovoltaic power generated by the over-sizing of the photovoltaic-storage system. The implementation principle of the control objectives in this embodiment will be explained in detail below.

[0070] like Figure 1 As shown, the photovoltaic-storage system includes a photovoltaic power generation device 120, an energy storage device 130, and an inverter 110. The inverter 110 is connected to the first DC converter 161 via a DC bus 150, establishing an electrical connection between the inverter 110 and the photovoltaic power generation device 120. The inverter 110 is also connected to the second DC converter 162 via a DC bus 150, establishing an electrical connection between the inverter 110 and the energy storage device 130. The AC terminal of the inverter 110 is connected to the grid connection point of the electrical load 140. A power sensor 170 is installed at the grid connection point to collect the current grid connection point power (i.e., the active power of the grid connection point) in real time.

[0071] When the output power of the first DC converter 161 is positive, it means that the power generated by the photovoltaic power generation device 120 is transferred to the DC bus 150. When the output power of the second DC converter 162 is positive, it means that the power on the DC bus 150 is transferred to the energy storage device 130. That is, when the energy storage device 130 is charging, the output power of the second DC converter 162 is positive, and when the energy storage device 130 is discharging, the output power of the second DC converter 162 is negative. When the inverter 110 transfers the power of the DC bus 150 to the electrical load 140 or the power grid 180, the output power of the inverter 110 is positive.

[0072] The current power generation capacity of photovoltaic power generation device 120 is The current power consumption of electrical load 140 is The output power of the first DC converter 161 is The output power of the second DC converter 162 is The output power of inverter 110 is .

[0073] On DC bus 150, according to the law of conservation of energy, the photovoltaic power transferred from the first DC converter 161 to DC bus 150 is equal to the sum of the power absorbed from DC bus 150 by the second DC converter 162 and inverter 110, i.e. .

[0074] When the photovoltaic power cannot meet the load operation, the energy storage device 130 discharges to supply the control target of the electrical load 140, and the logic is as follows: If the photovoltaic power cannot meet the load operation, then This may be during a period of low radiation, and the output power of inverter 110 has not reached its rated output power. ,Right now .

[0075] For the grid connection point power control module, based on the real-time fluctuations in the current grid connection point power, it is determined that there is electricity purchase activity at the grid connection point, and the first output power is calculated. Start increasing, until .

[0076] For the energy storage state of charge control module, the target state of charge is set based on the current state of charge. After the energy on the DC bus 150 is transferred to the energy storage device 130 by the second DC converter 162, the state of charge of the energy storage device 130 increases. As the current state of charge increases, the calculated second output power... Increase.

[0077] In this embodiment, by as well as It can be known that According to the target output power From the calculation formula, we can see that at this time... Received The upper limit limit, the output Assuming the output power of inverter 110 perfectly follows the target output power, and applying the law of conservation of energy, we have: At this point, it is known ,but The output power of the second DC converter 162 is negative, meaning the energy storage device 130 is discharging; when steady state is reached, the output power of the inverter 110 is... Equal to the current power consumption The output power of inverter 110 consists of two parts: one part is the power generated by photovoltaic power generation device 120, and the other part is the power discharged by energy storage device 130.

[0078] The control target of energy storage device 130 absorbing photovoltaic power generated by over-sizing of the photovoltaic-storage system can be subdivided into two sub-targets based on the relative level of irradiance (power generation). First, during periods of lower irradiance (when the current power generation is less than or equal to the rated output power of inverter 110), the power generation of photovoltaic power generation device 120 does not charge energy storage device 130. Second, during periods of higher irradiance (when the current power generation is greater than the rated output power of inverter 110), energy storage device 130 can absorb a portion of the photovoltaic power generation exceeding the rated output power of inverter 110, i.e., absorb the photovoltaic power generated by over-sizing of the photovoltaic-storage system.

[0079] I. Periods with lower irradiance ( ).

[0080] In some embodiments, determining the target output power of inverter 110 based on the first output power, the second output power, and the rated output power of inverter 110 includes: When the current power generation of the photovoltaic power generation device 120 is less than or equal to the rated output power, in response to the second output power being greater than the first output power, the target output power is determined to be equal to the second output power, and the second output power is determined based on the current power generation.

[0081] In this embodiment, for the grid connection point power control module, since The current grid connection point power is 0. Based on the current grid connection point power and the target grid connection point power, the first output power is calculated. =0.

[0082] For the energy storage state of charge control module, the target state of charge is set based on the current state of charge. After the second DC converter 162 transfers power from the DC bus 150 to the energy storage device 130, the state of charge of the energy storage device 130 increases. As the state of charge of the energy storage device 130 increases, the calculated second output power... Increase.

[0083] If the current state of charge of the energy storage device 130 increases, according to The calculation formula is as follows: the target output power is determined by the energy storage state of charge control module. In response to the second output power being greater than the first output power, the second output power acts as a lower limit; the target output power equals the second output power. .

[0084] Assuming the output power of inverter 110 perfectly follows the target output power, that is... Based on the above power relationship and energy conservation, we can obtain .

[0085] As the current state of charge increases, the target state of charge is set based on the current state of charge. And it keeps increasing, according to , The charging power of the energy storage device 130 is continuously decreasing.

[0086] When the grid connection point begins selling electricity, the output of the power control module at the grid connection point... As the power output of the grid connection point control module decreases continuously, the actual output of the grid connection point control module cannot be applied to the inverter 110 due to the lower limit of the second output power of the energy storage state of charge control module. As a result, the grid connection point power control module fails and loses control over the grid connection point power.

[0087] During the electricity sales period at the grid connection point, inverter 110 is controlled by the energy storage state of charge control module. It only reaches steady state when the energy storage device 130 discharges and controls the state of charge to the reference value. At this time, the actual output power of inverter 110 is equal to the current power generation of photovoltaic power generation device 120. ,at this time That is, the charging power of the energy storage device 130 is 0, the target output power is the second output power, the value of the second output power is equal to the current power generation, the current power generation of the photovoltaic power generation device 120 is given priority to the electrical load 140 or transferred to the grid 180, the power generation of the photovoltaic power generation device 120 does not charge the energy storage device 130, so as to create conditions for the energy storage device 130 to absorb the over-supplied photovoltaic power during the high irradiance period.

[0088] II. Periods of higher irradiance ( ).

[0089] In some embodiments, determining the target output power of inverter 110 based on the first output power, the second output power, and the rated output power of inverter 110 includes: When the current power generation of the photovoltaic power generation device 120 is greater than the rated output power, in response to the second output power being greater than the rated output power, the target output power is determined to be equal to the rated output power, the charging and discharging power of the energy storage device 130 is greater than 0, and the charging and discharging power of the energy storage device 130 is determined based on the current power generation and the rated output power.

[0090] In this embodiment, According to the law of conservation of energy The inverter 110 can reach its target output power limit, that is At this time, inverter 110 is unable to supply all of its current generating power to load 140 or transfer it to the grid 180. In this scenario, the charging and discharging power of the energy storage device 130 If the value is greater than 0, the energy storage device 130 enters the charging state.

[0091] For the energy storage state of charge control module, the target state of charge is the current state of charge, and the charging and discharging power of the energy storage device 130 is... As the state of charge of the energy storage device 130 increases continuously (greater than 0), the calculated second output power... It is also constantly increasing.

[0092] when At that time, the second output power output by the energy storage state of charge control module is subject to the rated output power of the inverter 110. Due to the limitation, the actual output of the energy storage state of charge control module cannot be applied to the inverter 110, the energy storage state of charge control module fails, and loses control over the state of charge of the energy storage device 130. The target output power is taken as the rated output power.

[0093] In this embodiment, when a steady state is reached, the charging and discharging power of the energy storage device 130, the current power generation of the photovoltaic power generation device 120, and the rated output power of the inverter 110 are related as follows:

[0094] The actual output power of inverter 110 is equal to its rated output power, and the charging and discharging power of energy storage device 130 is determined based on the current power generation and the rated output power. This enables the energy storage device 130 to absorb photovoltaic power generated due to over-sizing during periods of high irradiance.

[0095] It should be noted that by setting the current state of charge as the reference value target state of charge of the energy storage state of charge control module, the output is used as the lower limit of the second output power. Combined with the first output power and the rated output power, the target output power is calculated, and the output power of the inverter 110 is controlled. This enables the energy storage device 130 to absorb the photovoltaic power generated by the over-sizing during periods of higher irradiance, and not to charge the energy storage device 130 during periods of lower irradiance.

[0096] In some embodiments, if preset conditions are met, the target state of charge is set to the current state of charge.

[0097] It is understandable that the current state of charge of the energy storage device 130 is dynamically changing. It can be set to the target state of charge by setting preset conditions to trigger the update of the target state of charge. When the preset conditions are met, the real-time current state of charge is set to the target state of charge.

[0098] For example, at time T1, the target's state of charge =80%, at time T2, current state of charge. =85% and meets preset conditions, target state of charge =85%.

[0099] In some embodiments, the preset condition is that the change in the state of charge of the energy storage device 130 reaches a preset threshold.

[0100] Among them, the change in state of charge can refer to the increment of the state of charge.

[0101] During periods of high irradiance, the second output power of the energy storage state of charge (SCC) control module is limited by the rated output power of the inverter 110, causing the SCC control module to malfunction. During this period, the SCC of the energy storage device 130 continuously increases due to the absorption of over-sizing photovoltaic power, and the second output power continuously increases. When the irradiance decreases, there is a difference between the actual current SCC of the energy storage device 130 and the reference target SCC, and the target output power of the inverter 110 continues to be limited by the second output power. and rated output power The limiting effect allows the energy stored in the device 130 to be transferred to the load 140 or the power grid 180 during periods of low radiation.

[0102] In this embodiment, whenever the change in the state of charge of the energy storage device 130 reaches a preset threshold, such as when the state of charge of the energy storage device 130 increases by the preset threshold... ( Afterwards, the target state of charge (SBC) of the energy storage SBC control module is updated to the real-time current SBC. Even if the SBC increases due to the absorption of photovoltaic power generated by the over-sizing of the energy storage device 130, the difference between the reference value and the feedback value in the energy storage SBC control module is approximately zero because the reference value of the target SBC in the energy storage SBC control module is updated accordingly. This greatly reduces the risk of energy loss. The output of the energy storage state-of-charge control module acts on the inverter 110, preventing the transfer of electrical energy from the energy storage device 130 to the electrical load 140 or the power grid 180.

[0103] According to the control method of inverter 110 provided in the embodiments of this application, the first output power is calculated with grid connection point power control as the target, the second output power is calculated with state of charge control as the target, and the target output power for inverter 110 output power control is determined by combining the rated output power of inverter 110. This can reduce the passive curtailment of photovoltaic energy storage system during high irradiance periods, so that energy storage device 130 can fully absorb photovoltaic energy, effectively improve energy utilization and system power generation revenue.

[0104] The following are some specific implementation examples.

[0105] Example 1: When the photovoltaic power cannot meet the load operation, the energy storage device 130 discharges to supply the power load 140.

[0106] Assume that the current power generation of the photovoltaic power generation device 120 is 3kW, the current power consumption of the electrical load 140 is 5kW, and the rated output power of the inverter 110 is greater than the upper limit of the power consumption of the electrical load 140.

[0107] At this time, the power sensor 170 at the grid connection point samples an active power of -2kW. The reference value of the power control module at the grid connection point is 0, and the power control module outputs... =5kW.

[0108] Since the photovoltaic power flows to the electrical load 140, the current state of charge of the energy storage module will not increase, and the output will remain unchanged. ≤0.

[0109] according to From the calculation formula, we can see that... The inverter 110 output power consists of two parts: 3kW of photovoltaic power and 2kW of energy storage discharge power.

[0110] Example 2: Energy storage device 130 absorbs photovoltaic power generated due to over-sizing during periods of high irradiance.

[0111] Assume that the rated output power of inverter 110 is 6kW.

[0112] During periods of lower irradiance, assume that the current power generation of photovoltaic power generation device 120 is 4kW.

[0113] For the energy storage state of charge control module, the reference value is the current state of charge. After the second DC converter 162 transfers the electrical energy from the DC bus 150 to the energy storage device 130, the state of charge of the energy storage device 130 increases, and the energy storage state of charge control module outputs... Increase.

[0114] For the grid connection point power control module, since the grid connection point is selling electricity, the output of the grid connection point power control module is...

[0115] according to From the calculation formula, we can see that... In steady state, the charging power of energy storage device 130 is 0, and the output power of inverter 110, i.e., photovoltaic power, is 4kW. During periods of higher irradiance, it is assumed that the current power generation of photovoltaic power generation device 120 is 8kW.

[0116] For the energy storage state of charge control module, the reference value is the current state of charge. After the second DC converter 162 transfers the electrical energy from the DC bus 150 to the energy storage device 130, the state of charge of the energy storage device 130 increases, and the energy storage state of charge control module outputs... Increase.

[0117] For the grid connection point power control module, since the grid connection point is selling electricity, the output of the grid connection point power control module is...

[0118] according to From the calculation formula, we can see that... Due to the limitation of the rated power of the inverter 110, the energy storage device 130 is continuously charged, and its state of charge continuously increases, eventually... It will be limited by the rated power. .

[0119] In steady state, the photovoltaic power flows to the inverter 110 and the energy storage device 130. The inverter 110 outputs 6kW and the energy storage device 130 has a charging power of 2kW.

[0120] The control method for inverter 110 provided in this application embodiment can be executed by the control device of inverter 110. This application embodiment uses the control device of inverter 110 executing the control method of inverter 110 as an example to illustrate the control device of inverter 110 provided in this application embodiment.

[0121] This application embodiment also provides a control device for an inverter 110. The DC terminal of the inverter 110 is connected to a photovoltaic power generation device 120 and an energy storage device 130 respectively via a DC bus 150, and the AC terminal of the inverter 110 is connected to the grid connection point of the electrical load 140.

[0122] like Figure 6 As shown, the control device for the inverter 110 includes: The first processing module 610 is used to obtain the current grid connection point power of the grid connection point, and based on the current grid connection point power, with the target grid connection point power as a reference value, determine the first output power of the inverter 110; The second processing module 620 is used to obtain the current state of charge of the energy storage device 130, and based on the current state of charge, with the target state of charge as a reference value, determine the second output power of the inverter 110, wherein the target state of charge is determined based on the current state of charge. The third processing module 630 is used to determine the target output power of the inverter 110 based on the first output power, the second output power and the rated output power of the inverter 110. The fourth processing module 640 is used to control the output power of the inverter 110 with the target output power as a reference value.

[0123] According to the control device of the inverter 110 provided in the embodiments of this application, the first output power is calculated with grid connection point power control as the target, the second output power is calculated with state of charge control as the target, and the target output power for inverter 110 output power control is determined by combining the rated output power of inverter 110. This can reduce the passive curtailment of photovoltaic energy storage system during high irradiance periods, so that energy storage device 130 can fully absorb photovoltaic energy, effectively improve energy utilization and system power generation revenue.

[0124] In some embodiments, if preset conditions are met, the target state of charge is set to the current state of charge.

[0125] In some embodiments, the preset condition is that the change in the state of charge of the energy storage device 130 reaches a preset threshold.

[0126] In some embodiments, the third processing module 630 is configured to determine the target output power of the inverter 110 based on the first output power, the second output power, and the rated output power of the inverter 110, including: With the second output power as the lower limit and the rated output power as the upper limit, the first output power, the second output power, and the rated output power are compared, and the target output power is determined based on the comparison results.

[0127] In some embodiments, the third processing module 630 is configured to compare the first output power, the second output power, and the rated output power, and determine the target output power based on the comparison result, including: Application formula

[0128] Determine the target output power; in, For the target output power, Rated output power, For the first output power, This is the second output power.

[0129] In some embodiments, the third processing module 630 is configured to determine the target output power of the inverter 110 based on the first output power, the second output power, and the rated output power of the inverter 110, including: When the current power generation of the photovoltaic power generation device 120 is greater than the rated output power, in response to the second output power being greater than the rated output power, the target output power is determined to be equal to the rated output power, the charging and discharging power of the energy storage device 130 is greater than 0, and the charging and discharging power of the energy storage device 130 is determined based on the current power generation and the rated output power.

[0130] In some embodiments, the third processing module 630 is configured to determine the target output power of the inverter 110 based on the first output power, the second output power, and the rated output power of the inverter 110, including: When the current power generation of the photovoltaic power generation device 120 is less than or equal to the rated output power, in response to the second output power being greater than the first output power, the target output power is determined to be equal to the second output power, and the second output power is determined based on the current power generation.

[0131] In some embodiments, the target grid connection point power is 0.

[0132] The control device for the inverter 110 provided in this application embodiment can realize the various processes implemented in the above-described control method embodiment for the inverter 110. To avoid repetition, it will not be described again here.

[0133] This application also provides a photovoltaic energy storage system.

[0134] like Figure 1 As shown, the photovoltaic-storage system includes: a photovoltaic power generation device 120, an energy storage device 130, and an inverter 110.

[0135] The DC terminal of the inverter 110 is connected to the photovoltaic power generation device 120 and the energy storage device 130 respectively via the DC bus 150. The AC terminal of the inverter 110 is connected to the grid connection point of the electrical load 140. The photovoltaic-energy storage system also includes a control device for the inverter 110 as described above. The control device is used to control the output power of the inverter 110.

[0136] According to the photovoltaic-storage system provided in the embodiments of this application, the first output power is calculated with grid connection point power control as the target, and the second output power is calculated with state of charge control as the target. Combined with the rated output power of inverter 110, the target output power for inverter 110 output power control is determined. This can reduce the passive curtailment of photovoltaic energy during periods of high irradiance, enabling the energy storage device 130 to fully absorb photovoltaic energy and effectively improve energy utilization and system power generation revenue.

[0137] This application also provides a non-transitory computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the various processes of the control method embodiment of the inverter 110 described above and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0138] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0139] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the control method of the inverter 110 described above.

[0140] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0141] This application embodiment also provides a chip, which includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is used to run programs or instructions to implement the various processes of the control method embodiment of the inverter 110 described above, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0142] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0143] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0144] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the related technology, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0145] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

[0146] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0147] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A control method of an inverter, characterized by, The direct current end of the inverter is connected with the photovoltaic power generation device and the energy storage device through a direct current bus, the alternating current end of the inverter is connected with the power load and the grid connection point, and the method comprises the following steps: acquiring a current grid connection point power of the grid connection point, and determining a first output power of the inverter based on the current grid connection point power and taking a target grid connection point power as a reference value; acquiring a current state of charge of the energy storage device, and determining a second output power of the inverter based on the current state of charge and taking a target state of charge as a reference value, wherein the target state of charge is determined based on the current state of charge; determining a target output power of the inverter based on the first output power, the second output power and a rated output power of the inverter; controlling the output power of the inverter by taking the target output power as a reference value.

2. The control method of the inverter according to claim 1, characterized by, In the case of meeting a preset condition, the target state of charge is set as the current state of charge.

3. The control method of the inverter according to claim 2, characterized by, The preset condition is that a state of charge variation amount of the energy storage device reaches a preset threshold.

4. The control method of the inverter according to claim 1, characterized by, The determination of the target output power of the inverter based on the first output power, the second output power and the rated output power of the inverter comprises the following steps: comparing the first output power, the second output power and the rated output power under the condition that the second output power is taken as a lower limit of power and the rated output power is taken as an upper limit of power, and determining the target output power according to a comparison result.

5. The control method of the inverter according to claim 4, characterized by, The comparison of the first output power, the second output power and the rated output power and the determination of the target output power according to a comparison result comprises the following steps: applying a formula to determine the target output power. The determination of the target output power of the inverter based on the first output power, the second output power and the rated output power of the inverter comprises the following steps: wherein, is the target output power, is the rated output power, is the first output power, is the second output power.

6. The control method of the inverter according to any one of claims 1 to 5, characterized by, in the case that a current power generation power of the photovoltaic power generation device is greater than the rated output power, in response to the second output power being greater than the rated output power, the target output power is determined to be equal to the rated output power, and a charge and discharge power of the energy storage device is greater than 0 and is determined based on the current power generation power and the rated output power. The determination of the target output power of the inverter based on the first output power, the second output power and the rated output power of the inverter comprises the following steps:

7. The control method of the inverter according to any one of claims 1 to 5, characterized by, in the case that the current power generation power of the photovoltaic power generation device is less than or equal to the rated output power, in response to the second output power being greater than the first output power, the target output power is determined to be equal to the second output power, and the second output power is determined based on the current power generation power. The target grid connection point power is 0.

8. The control method of the inverter according to any one of claims 1 to 5, characterized by, The direct current end of the inverter is connected with the photovoltaic power generation device and the energy storage device through a direct current bus, the alternating current end of the inverter is connected with the power load and the grid connection point, and the control device comprises:

9. A control device of an inverter, characterized by comprising: ​ The first processing module is configured to acquire a current grid-connected point power of the grid-connected point, and determine a first output power of the inverter based on the current grid-connected point power and a target grid-connected point power as a reference value. The second processing module is configured to acquire a current state of charge of the energy storage device, and determine a second output power of the inverter based on the current state of charge and a target state of charge as a reference value, the target state of charge being determined based on the current state of charge. The third processing module is configured to determine a target output power of the inverter based on the first output power, the second output power and a rated output power of the inverter. The fourth processing module is configured to control the output power of the inverter based on the target output power as a reference value.

10. A light storage system characterized by, The photovoltaic power generation device, the energy storage device and the inverter are included. The direct current end of the inverter is connected to the photovoltaic power generation device and the energy storage device through a direct current bus, the alternating current end of the inverter is connected to the grid-connected point and the power load, and the light and storage system further comprises the control device of the inverter according to claim 9. ​

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