Photovoltaic control system

Abstract

The application discloses a photovoltaic control system and relates to the technical field of power electronics. The switching control circuit in the system at least comprises a controller and a three-phase high-voltage adapter arranged between a photovoltaic input main circuit and a grid-connected main circuit. Each high-voltage adapter comprises at least one group of operation modules. Each group of operation modules at least comprises an energy storage unit and a high-frequency conversion unit of a solid-state transformer. The controller is used to determine a target number of started operation modules according to total photovoltaic active power output by the photovoltaic input main circuit, operation state data of a plurality of operation modules in the switching control circuit and grid-connected side three-phase voltage values output by the grid-connected main circuit, and control instructions carrying the target number are sent to the three-phase high-voltage adapter. The application solves the technical problem that a single power frequency step-up transformer in a distributed photovoltaic system is in a low-load / empty-load state for a long time due to large day-night output difference and strong irradiation fluctuation, thereby resulting in low overall operation efficiency of the system and high equipment loss.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and more specifically, to a photovoltaic control system. Background Technology

[0002] Currently, medium-capacity (e.g., 10kV) distributed photovoltaic (PV) control systems generally adopt a discrete architecture of "string inverter + AC combiner cabinet + single power frequency step-up transformer". Although the power frequency step-up transformer is widely used in this architecture due to its mature technology, low cost, and strong shock resistance, as a fixed-capacity device, it still has the following significant drawbacks in practical applications: First, the power frequency step-up transformer in the discrete architecture is a fixed-capacity device. Affected by the large diurnal variation and strong fluctuations in PV output, it cannot dynamically adjust its operating scale according to the real-time PV output. This results in it being in a low-load or no-load state for a long time during operation. At this time, the core excitation loss inside the power frequency step-up transformer accounts for a very high proportion, resulting in extremely low operating efficiency and a large amount of ineffective energy waste. Second, this discrete architecture only disconnects the transformer when the PV output is zero. This frequent switching not only shortens the equipment lifespan but also easily causes voltage surges to the distribution network and cannot solve the efficiency waste problem in the low-load range (non-zero but low power).

[0003] There is currently no effective solution to the above problems. Summary of the Invention

[0004] This application provides a photovoltaic control system to at least solve the technical problem that the single power frequency step-up transformer used in distributed photovoltaic systems is in a low-load / no-load state for a long time due to the large difference in output between day and night and the strong irradiance fluctuations, resulting in low overall system operating efficiency and high equipment loss.

[0005] According to one aspect of the embodiments of this application, a photovoltaic control system is provided. The photovoltaic control system includes at least: a photovoltaic input main circuit, a switching control circuit, and a grid-connected main circuit. The switching control circuit includes at least: a controller and a three-phase high-voltage adapter disposed between the photovoltaic input main circuit and the grid-connected main circuit. Each phase high-voltage adapter includes at least one set of operating modules. Each set of operating modules includes at least: an energy storage unit and a solid-state transformer high-frequency conversion unit. The controller is used to determine the target number of operating modules to be turned on based on the total photovoltaic active power output from the photovoltaic input main circuit, the operating status data of multiple operating modules in the switching control circuit, and the grid-connected three-phase voltage value output from the grid-connected main circuit, and to send a control command carrying the target number to the three-phase high-voltage adapter.

[0006] In one exemplary embodiment, the photovoltaic input main circuit includes at least: a plurality of inverters and an AC combiner module, wherein the input terminals of the plurality of inverters are connected to the photovoltaic array, and the output terminals of the plurality of inverters are connected to the input terminals of the AC combiner module; the AC combiner module includes at least: a low-voltage circuit breaker and an AC combiner bus, wherein the input terminal of the low-voltage circuit breaker is connected to the output terminals of the plurality of inverters, the output terminal of the low-voltage circuit breaker is connected to the input terminal of the AC combiner bus, and the output terminal of the AC combiner bus is connected to the input terminal of the switching control circuit.

[0007] In one exemplary embodiment, each operating module further includes: a DC-DC converter and a high-voltage circuit breaker, wherein the input terminal of the energy storage unit is connected to the output terminal of the AC busbar in the photovoltaic input main circuit, and the output terminal of the energy storage unit is connected to the input terminal of the DC-DC converter; the input terminal of the solid-state transformer high-frequency conversion unit is connected to the output terminal of the DC-DC converter, and the output terminal of the solid-state transformer high-frequency conversion unit is connected to the input terminal of the three-phase high-voltage adapter; the input terminal of the high-voltage circuit breaker is connected to the output terminal of the three-phase high-voltage adapter, and the output terminal of the high-voltage circuit breaker is connected to the grid-connected main circuit.

[0008] In an exemplary embodiment, the grid-connected main circuit includes at least: a grid-connected circuit breaker and a grid-connected bus, wherein the grid-connected circuit breaker is disposed between the output terminal of the high-voltage circuit breaker and the grid-connected bus.

[0009] In an exemplary embodiment, the switching control loop further includes: a data acquisition unit, whose operating status data includes at least: energy storage data of the energy storage unit and module status data of the solid-state transformer high-frequency converter unit. The input terminal of the data acquisition unit is connected to the output terminal of the AC bus in the photovoltaic input main circuit, the input terminal of the grid-connected bus in the grid-connected main circuit, the output terminal of the energy storage unit within each group of operating modules, and the output terminal of the solid-state transformer high-frequency converter unit. The output terminal of the data acquisition unit is connected to the input terminal of the controller, used to send the acquired total photovoltaic active power, grid-connected three-phase voltage values, energy storage data of the energy storage units within each group of operating modules, and module status data of the solid-state transformer high-frequency converter unit to the controller. The output terminal of the controller is connected to the input terminal of the three-phase high-voltage adapter, used to determine the target operating mode based on the total photovoltaic active power, grid-connected three-phase voltage values, and energy storage data of each energy storage unit; determine the target quantity based on the target operating mode, grid-connected three-phase voltage values, total photovoltaic active power, energy storage data of each energy storage unit, and module status data of each group of operating modules, and send a control command carrying the target quantity to control the three-phase high-voltage adapter.

[0010] In an exemplary embodiment, the energy storage data includes at least: battery state of charge; determining a target operating mode based on the total photovoltaic active power, the three-phase voltage value on the grid-connected side, and the energy storage data of each energy storage unit, including: determining the photovoltaic output level based on the relationship between the total photovoltaic active power and a preset power threshold, wherein the photovoltaic output level includes at least: no-load level or low-load level; determining the grid-connected voltage state based on the relationship between the three-phase voltage value on the grid-connected side and a preset upper limit value and a preset lower limit value of the grid-connected voltage, wherein the grid-connected voltage state includes: normal state or over-limit state; determining the energy storage scheduling state based on the battery state of charge of each energy storage unit and a preset maximum available state of charge threshold and a preset minimum available state of charge threshold, wherein the energy storage scheduling state includes: charging state or discharging state; determining a target operating mode matching the photovoltaic output level, grid-connected voltage state, and energy storage scheduling state from a preset operating mode logic table, wherein the operating mode logic table includes the photovoltaic output level, grid-connected voltage state, and energy storage scheduling state corresponding to each of the various operating modes.

[0011] In one exemplary embodiment, determining a target operating mode that matches the photovoltaic output level, grid-connected voltage state, and energy storage dispatch state from a preset operating mode logic table includes: determining the target operating mode as reactive power support mode when the grid-connected voltage state is in an over-limit state; determining the target operating mode as energy storage stabilization mode when the grid-connected voltage state is in a normal state, the photovoltaic output level is at an unloaded level, and the energy storage dispatch state is in a charging state; determining the target operating mode as high-efficiency power generation mode when the grid-connected voltage state is in a normal state, the photovoltaic output level is at a low load level, and the energy storage dispatch state is in a discharging state; and determining the target operating mode as idle standby mode when the grid-connected voltage state is in a normal state and the photovoltaic output level is at an unloaded level.

[0012] In one exemplary embodiment, the module status data includes at least: status data of the solid-state transformer high-frequency conversion unit; determining the target quantity based on the target operating mode, the grid-connected three-phase voltage value, the total active power of photovoltaics, the energy storage data of each energy storage unit, and the module status data of each group of operating modules includes: determining the set of available operating modules based on the status data of the solid-state transformer high-frequency conversion unit in each operating module, and determining the total number of modules in the set of available operating modules; determining the theoretical number of modules corresponding to the target operating mode based on the target operating mode, the grid-connected three-phase voltage value, the total active power of photovoltaics, the energy storage data of each energy storage unit, and the module status data of each group of operating modules; comparing the theoretical number of modules with the total number of modules in the set of available operating modules; if the theoretical number of modules is not greater than the total number of modules, the theoretical number of modules is taken as the target quantity; if the theoretical number of modules is greater than the total number of modules, the total number of modules is taken as the target quantity.

[0013] In an exemplary embodiment, the energy storage data further includes: maximum charging and discharging power; the module status data further includes: maximum reactive power output and minimum active power required to achieve optimal efficiency. Based on the target operating mode, the grid-connected three-phase voltage value, the total photovoltaic active power, and the energy storage data of each energy storage unit and the module status data of each group of operating modules, the theoretical number of modules corresponding to the target operating mode is determined, including: when the target operating mode is a reactive power support mode, determining the target reactive power based on the grid-connected three-phase voltage value, and rounding up the quotient obtained by dividing the target reactive power by the average of the maximum reactive power output of all operating modules to obtain the theoretical number of modules; when the target operating mode is an energy storage mitigation mode, determining the predicted value of the total photovoltaic active power of the photovoltaic array based on the historical photovoltaic active power sequence of the photovoltaic array and real-time meteorological monitoring data, and combining... The total energy storage charging and discharging power of all energy storage units is determined using a pre-defined smooth control algorithm. The quotient of the total energy storage charging and discharging power divided by the maximum charging and discharging power of each energy storage unit is rounded up to obtain the theoretical number of modules. Under the target operating mode of high-efficiency power generation, the quotient of the total photovoltaic active power divided by the average of the minimum active power of all operating modules is rounded up to obtain the basic number of modules. The number of energy storage units within the preset state of charge range and in the discharging state is then determined. If the number of basic modules is less than the number of energy storage units, the number of auxiliary support modules is determined to be the basic number of modules. If the number of basic modules is not less than the number of energy storage units, the number of auxiliary support modules is determined to be zero. The sum of the number of basic modules and the number of auxiliary support modules is taken as the theoretical number of modules. Under the target operating mode of idle standby mode, the theoretical number of modules is determined to be zero.

[0014] In one exemplary embodiment, sending a control command carrying a target number to the control three-phase high-voltage adapter includes: sending a first control command to the three-phase high-voltage adapter when the target operating mode is an idle standby mode, wherein the first control command is used to instruct the suspension of operation of all operating modules within the three-phase high-voltage adapter; and sending a second control command to the three-phase high-voltage adapter when the target operating mode is a reactive power support mode, an energy storage balancing mode, or a high-efficiency power generation mode, wherein the second control command is used to instruct the control three-phase high-voltage adapter to start operation of a target number of operating modules.

[0015] The photovoltaic control system in this embodiment includes at least: a photovoltaic input main circuit, a switching control circuit, and a grid-connected main circuit. The switching control circuit includes at least: a controller and a three-phase high-voltage adapter disposed between the photovoltaic input main circuit and the grid-connected main circuit. Each phase high-voltage adapter includes at least one set of operating modules. Each set of operating modules includes at least: an energy storage unit and a solid-state transformer high-frequency conversion unit. The controller is used to determine the target number of operating modules to be turned on based on the total active power of photovoltaic output from the photovoltaic input main circuit, the operating status data of multiple operating modules in the switching control circuit, and the grid-connected three-phase voltage value output from the grid-connected main circuit. The controller then sends a control command carrying the target number to the three-phase high-voltage adapter, thereby realizing the dynamic adjustment of the number of operating modules to be turned on. This ensures that the operating modules are in operation within the high-efficiency load range and eliminates ineffective losses under no-load conditions. This solves the technical problem of low overall system efficiency and high equipment loss caused by the long-term low-load / no-load state of a single power frequency step-up transformer used in distributed photovoltaic systems due to large day-night output differences and strong irradiance fluctuations. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0017] Figure 1 This is a schematic diagram of a photovoltaic control system according to an embodiment of this application;

[0018] Figure 2 This is a schematic diagram of an optional photovoltaic input main circuit 11 according to an embodiment of this application;

[0019] Figure 3 This is a schematic diagram of an optional switching control loop 12 according to an embodiment of this application;

[0020] Figure 4 This is a schematic diagram of the structure of an optional single-phase high-voltage adapter 12i according to an embodiment of this application;

[0021] Figure 5 This is a schematic diagram of the structure of an optional solid-state transformer high-frequency conversion unit j3 according to an embodiment of this application;

[0022] Figure 6 This is a schematic diagram of an optional grid-connected main circuit 13 according to an embodiment of this application;

[0023] Figure 7 This is a structural block diagram of an optional controller according to an embodiment of this application. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0025] It should be noted that the terms "first," "second," etc., used in the specification, claims, and drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] According to an embodiment of this application, a photovoltaic control system is provided. Figure 1 This is a schematic diagram of a photovoltaic control system according to an embodiment of this application, such as... Figure 1 As shown, the system includes at least: a photovoltaic input main circuit 11, a switching control circuit 12, and a grid-connected main circuit 13, wherein:

[0027] The photovoltaic input main circuit 11 is used to collect the electrical energy generated by the photovoltaic array and transmit it to the switching control circuit 12.

[0028] The switching control loop 12 is used to convert the electrical energy input from the photovoltaic input main loop 11 into high-voltage AC power that meets the grid connection requirements, and to change the total system capacity by switching on or off the operating modules to match the real-time output of the photovoltaic system and avoid the transformer from operating under low load / no load.

[0029] The grid-connected main circuit 13 safely and efficiently outputs the transformed and regulated electrical energy to the power grid, achieving synchronization and electrical isolation with the grid.

[0030] Optionally, Figure 2 This is a schematic diagram of an optional photovoltaic input main circuit 11 according to an embodiment of this application, as shown below. Figure 2As shown, the photovoltaic input main circuit 11 includes at least: multiple (string) inverters 111 (including inverter 1111, inverter 1112, ..., inverter 111M) and an AC combiner module 112 (also known as a low-voltage AC combiner cabinet), wherein:

[0031] The input terminals of multiple inverters 111 are connected to an external photovoltaic array, and the output terminals of multiple inverters 111 are connected to the input terminal of an AC combiner module 112. The photovoltaic array is a power generation assembly composed of multiple photovoltaic strings connected in series and / or parallel, used to directly convert solar radiation energy into DC power. The multiple inverters 111 are the core power conversion devices in the photovoltaic input main circuit 11, each inverter 111m ( Connect one or more photovoltaic strings to convert the direct current output of the photovoltaic array into alternating current.

[0032] The AC busbar module 112 includes at least: a low-voltage circuit breaker 1121 and an AC busbar 1122, wherein: the input terminal of the low-voltage circuit breaker 1121 is connected to the output terminal of multiple inverters 111, the output terminal of the low-voltage circuit breaker 1121 is connected to the input terminal of the AC busbar 1122, and the output terminal of the AC busbar 1122 is connected to the input terminal of the switching control circuit 12.

[0033] Specifically, the low-voltage circuit breaker 1121 is an electrical protection switch located between multiple inverters 111 and the AC bus 1122. Its rated voltage is adapted to the low-voltage AC output level of the inverter (such as 690V, 400V or 315V). It is used to automatically disconnect the connection between the branch and the AC bus 1122 when a fault occurs in a certain inverter (such as short circuit or overload), so as to prevent the fault from spreading and affecting other inverters or downstream equipment.

[0034] Specifically: AC bus 1122 is a conductive metal conductor (usually a copper bus or aluminum bus) used to collect the low-voltage AC output from multiple inverters 111 into a larger composite AC current. It serves as an electrical bridge between the inverter side and the subsequent high-voltage adapter side, ensuring that electrical energy is transmitted from the photovoltaic side to the switching control circuit 12.

[0035] Optionally, Figure 3 This is a schematic diagram of an optional switching control loop 12 according to an embodiment of this application, as shown below. Figure 3 As shown, the switching control loop 12 includes at least: a controller 121 and a three-phase high-voltage adapter 12i (i=2,3,4) disposed between the photovoltaic input main loop and the grid-connected main loop, wherein:

[0036] (I) The controller 121 can determine the target number of operating modules to be turned on based on the total active power of photovoltaics output from the photovoltaic input main circuit 11 (representing the amount of “source” power that the current system needs to process or transmit), the operating status data of multiple operating modules in the switching control circuit 12, and the grid-connected three-phase voltage value output from the grid-connected main circuit 13, so that the total active power of photovoltaics is distributed as evenly as possible on these modules, and the load rate of each module falls within the optimal efficiency range. Finally, the controller 121 sends the control command carrying the target number to the three-phase high-voltage adapter 12i.

[0037] Specifically, the controller 121 can control the three-phase high-voltage adapter 12i through the following steps:

[0038] Step S1: Based on the total active power of photovoltaics, the three-phase voltage value on the grid-connected side, and the energy storage data of each energy storage unit, determine the target operating mode. The target operating mode includes one of the following: no-load standby mode, low-load optimization mode, normal service mode, and auxiliary service mode.

[0039] Alternatively, step S1 above can be implemented through the following steps:

[0040] Step S11, based on the total active power of photovoltaic power With preset power threshold The size relationship determines the photovoltaic output level. Among them, the photovoltaic output level includes at least: no-load level or low-load level.

[0041] Specifically: if the total active power of photovoltaic power Less than the power threshold If so, it indicates the photovoltaic output level. It is a low-load level; if the total active power of photovoltaic power is... If the value is 0, it indicates the photovoltaic power output level. It is an unloaded level.

[0042] Step S12, based on the three-phase voltage values ​​on the grid-connected side and the preset upper limit of grid connection voltage Preset lower limit of grid-connected voltage The magnitude relationship determines the grid-connected voltage status. Among them, the grid-connected voltage status includes: normal status or over-limit status.

[0043] Specifically: if the three-phase voltage value on the grid-connected side Higher than the upper limit of grid connection voltage Or below the lower limit of grid connection voltage Then the grid-connected voltage state This is an over-limit condition; however, if the three-phase voltage value on the grid-connected side... Not higher than and not lower than the lower limit of grid connection voltage Then the grid-connected voltage state This is the normal state.

[0044] Step S13: Based on the battery state of charge (SOC) of each energy storage unit and the preset maximum available state of charge threshold. Preset minimum available state of charge threshold Determine the energy storage dispatch status The energy storage scheduling status includes: charging status, discharging status, or non-charging / discharging status.

[0045] Specifically: Iterate through all energy storage units within all operating modules. If the state of charge (SOC) of all energy storage units is lower than the minimum available state of charge threshold... If so, then the energy storage dispatch status This indicates that the stored energy capacity is insufficient and only has charging capability; if the state of charge (SOC) of all energy storage units is higher than the maximum available state of charge threshold... If so, then the energy storage dispatch status This indicates that the stored energy has sufficient capacity and is capable of discharging.

[0046] Step S14: Determine the target operating mode that matches the photovoltaic output level, grid connection voltage status and energy storage dispatch status from the preset operating mode logic table. The operating mode logic table includes the photovoltaic output level, grid connection voltage status and energy storage dispatch status corresponding to each of the various operating modes.

[0047] The above step S14 can be implemented according to the following rules:

[0048] (1) Under grid-connected voltage conditions In the case of exceeding the limit, the target operating mode is determined to be the reactive power support mode;

[0049] (2) Under grid-connected voltage conditions It is in normal condition, and the photovoltaic output level is [not specified]. It is at the no-load level (i.e., the photovoltaic output is zero or extremely low) and in energy storage dispatch status. When the energy storage unit is in a charging state (i.e., the energy storage unit has the ability to charge), the target operating mode is determined to be the energy storage smoothing mode.

[0050] (3) Under grid-connected voltage conditions It is in normal condition, and the photovoltaic output level is [not specified]. It is at a low load level and in energy storage dispatch status. When the energy storage unit is in a discharge state (i.e., the energy storage unit has the ability to discharge), the target operating mode is determined to be the high-efficiency power generation mode.

[0051] (4) Under grid-connected voltage conditions It is in normal condition, and the photovoltaic output level is [not specified]. When the load level is no load (i.e., the photovoltaic output is zero or extremely low), the target operating mode is determined to be idle standby mode.

[0052] Step S2: Determine the target quantity based on the target operating mode, the total active power of photovoltaics, the energy storage data of each energy storage unit, and the module status data of each group of operating modules.

[0053] The status data of this module includes, but is not limited to: status data of the solid-state transformer high-frequency conversion unit (including but not limited to fault codes, operating status, communication connection status, etc.), maximum reactive power output, and minimum active power required to be in the optimal efficiency range.

[0054] It should be noted that the maximum reactive power output of the operating module is determined by first establishing the basic upper limit of reactive power output based on the rated power parameters of the internal solid-state transformer high-frequency converter unit, and then dynamically adjusting this upper limit based on the power factor limitation and heat dissipation data of the solid-state transformer high-frequency converter unit at the current analysis moment. Therefore, if the solid-state transformer high-frequency converter unit within an operating module is under high load active power output or high temperature conditions, its maximum reactive power output is limited to a value lower than the rated upper limit. Conversely, if the solid-state transformer high-frequency converter unit within an operating module is under low load active power output or low temperature conditions, the maximum reactive power output is set to a value close to the basic upper limit.

[0055] In addition, regarding the minimum active power, it is determined by first setting the lower limit of the optimal efficiency range based on the rated power parameters of the internal solid-state transformer high-frequency conversion unit, and then dynamically correcting the lower limit of the optimal efficiency range based on the status data at the current analysis time (such as temperature rise status, the health of switching devices, and the aging degree of filter capacitors). Therefore, for modules with high temperature rise or low device health, the minimum active power is appropriately increased to avoid areas where efficiency drops sharply or losses are too high under low load; while for modules with low temperature rise or high device health, the minimum active power is maintained or slightly reduced so that they can maintain high operating efficiency under lower load.

[0056] Alternatively, step S2 above can be implemented through the following steps:

[0057] Step S21: Based on the status data of the solid-state transformer high-frequency conversion unit in each operating module, determine the set of available operating modules and the total number of modules in the set of available operating modules.

[0058] Specifically, all operating modules whose internal solid-state transformer high-frequency conversion unit is in "normal state", has a fault code of "empty" or "cleared", and has a communication connection status of "online" are selected. These available operating modules are then aggregated to obtain a set of available operating modules. The total number of modules in the set of available operating modules is then counted.

[0059] Step S22: Based on the target operating mode, the three-phase voltage value on the grid-connected side, the total active power of photovoltaics, the energy storage data of each energy storage unit, and the module status data of each group of operating modules, determine the theoretical number of modules corresponding to the target operating mode.

[0060] The above step S22 can be implemented as follows:

[0061] (1) When the target operating mode is the reactive power support mode, the target reactive power is determined based on the three-phase voltage value on the grid-connected side, and the quotient obtained by dividing the target reactive power by the average value of the maximum reactive power output of all operating modules is rounded up to obtain the theoretical number of modules.

[0062] The aforementioned target reactive power is determined by using a preset reactive power-voltage droop characteristic curve or proportional-integral control logic to determine the reactive power corresponding to the voltage deviation between the three-phase voltage value on the grid side and a preset grid voltage reference value (i.e., the rated voltage value or the target voltage value determined according to the grid dispatch instructions). Specifically: when the voltage deviation is greater than zero, the required target reactive power is positive, instructing the photovoltaic control system to output inductive reactive power to the grid or absorb capacitive reactive power to reduce the voltage; when the voltage deviation is less than zero, the required target reactive power is negative, instructing the photovoltaic control system to output capacitive reactive power to the grid or absorb inductive reactive power to support the voltage; when the voltage deviation is equal to zero, the required target reactive power is zero.

[0063] (2) When the target operation mode is the energy storage smoothing mode, based on the historical total active power sequence of the photovoltaic array in the previous time period of the current analysis time and the real-time meteorological monitoring data of the current analysis time, the predicted value of the total active power of the photovoltaic array in the period after the current analysis time is determined, and the total energy storage charging and discharging power of all energy storage units is determined by combining the preset smoothing control algorithm. The quotient of the total energy storage charging and discharging power divided by the maximum charging and discharging power of the energy storage unit is rounded up to obtain the theoretical number of modules.

[0064] Specifically: The historical total active power sequence of the photovoltaic array in the time period preceding the current analysis moment, along with real-time meteorological monitoring data (such as irradiance, temperature, and cloud cover) at the current analysis moment, are acquired. The acquired data is then analyzed using a photovoltaic power prediction model to obtain the predicted total active power of the photovoltaic array in a preset time period (e.g., the next 5 minutes to one hour) following the current analysis moment. Next, based on the predicted total active power of the photovoltaic array in the preset time period, the theoretical rate of change is determined, and the fluctuation component exceeding the preset smoothing standard is identified. This fluctuation component is then used as the input variable for the smoothing control algorithm. By solving the corresponding smoothing control function, the instantaneous charging and discharging power of the energy storage unit required to compensate for this fluctuation component—the required total energy storage charging and discharging power—is obtained. Therefore, if the fluctuation component is positive and greater than the preset threshold, the required total energy storage charging and discharging power is the charging power, indicating that the energy storage unit absorbs excess power; if the fluctuation component is negative and its absolute value is greater than the preset threshold, the required total energy storage charging and discharging power is the discharging power, indicating that the energy storage unit releases power to supplement the insufficient photovoltaic output; if the fluctuation component is less than the preset threshold, the required total energy storage charging and discharging power is zero.

[0065] (3) When the target operating mode is the high-efficiency power generation mode, the quotient obtained by dividing the total active power of photovoltaic by the average of the minimum active power of all operating modules is rounded up to obtain the number of basic modules, and the number of energy storage units that are in the preset state of charge range and in the state of discharge (i.e., the number of energy storage units that participate in power support) is determined; when the number of basic modules is less than the number of energy storage units, the number of auxiliary support modules is determined to be the number of basic modules; when the number of basic modules is not less than the number of energy storage units, the number of auxiliary support modules is determined to be zero; the sum of the number of basic modules and the number of auxiliary support modules is taken as the theoretical number of modules.

[0066] (4) When the target operating mode is idle standby mode, the theoretical number of modules is determined to be zero.

[0067] Step S23: Compare the theoretical number of modules with the total number of modules in the available running module set. If the theoretical number of modules is not greater than the total number of modules, proceed to step S24. If the theoretical number of modules is greater than the total number of modules, proceed to step S25.

[0068] Step S24: Use the theoretical number of modules as the target number.

[0069] Step S25: Use the total number of modules as the target number.

[0070] Step S3: Send the control command carrying the target quantity to the control three-phase high-voltage adapter 12i.

[0071] Specifically: When the target operating mode is idle standby mode, a first control command is sent to the three-phase high-voltage adapter 12i. The first control command is used to instruct the operation of all operating modules in the three-phase high-voltage adapter 12i to be suspended. This means not only stopping the transmission of active power, but also stopping the operation of the switching devices inside the modules (i.e. providing high-frequency inverter / rectification process).

[0072] Specifically: when the target operating mode is reactive power support mode, energy storage stabilization mode or high-efficiency power generation mode, a second control command is sent to the three-phase high-voltage adapter 12i, wherein the second control command is used to instruct the target number of operating modules in the three-phase high-voltage adapter 12i to start operation.

[0073] In summary, by differentiating between different operating modes, the controller achieves high efficiency and flexible control of the photovoltaic control system under all operating conditions: during idle standby, all module operation is completely suspended, eliminating the inherent no-load iron loss of traditional transformers. Apart from a small amount of power consumption in the standby control circuit, the main power circuit has almost no loss, achieving true "zero no-load loss"; in the "functional operation" mode, the controller dynamically and precisely activates a target number of operating modules, ensuring that the modules are always in the optimal efficiency range to maximize power generation benefits, and utilizing the modular redundancy characteristics to provide fast-response grid auxiliary services. This significantly reduces the total life cycle operation and maintenance costs while greatly improving the economic efficiency, reliability, and grid friendliness of the power station.

[0074] (II) A three-phase high-voltage adapter is installed between the photovoltaic input main circuit 11 and the grid-connected main circuit 13, namely A-phase high-voltage adapter 122 (or first-phase high-voltage adapter, U-phase high-voltage adapter), B-phase high-voltage adapter 123 (or second-phase high-voltage adapter, V-phase high-voltage adapter), and C-phase high-voltage adapter 124 (or third-phase high-voltage adapter, W-phase high-voltage adapter). These three-phase high-voltage adapters 12i respectively process the A-phase AC power, B-phase AC power and C-phase AC power from the photovoltaic input main circuit 11, and the output terminals 12i of the three-phase high-voltage adapters are connected to the grid-connected main circuit 13.

[0075] Specifically, each phase of the high-voltage adapter 12i typically has the same modular structure. Figure 4 This is a schematic diagram of an optional single-phase high-voltage adapter 12i according to an embodiment of this application, as shown below. Figure 4 As shown, each phase high-voltage adapter 12i (i=2,3,4) includes one or more operating modules 12iN. For ease of explanation, Figure 4The diagram illustrates multiple operating modules, including the first operating module 12ia, the second operating module 12ib, ..., the Nth operating module 12iN. Each operating module j (j=1,2,...,N) includes at least: an energy storage unit j1, a DC-DC converter j2, a solid-state transformer high-frequency conversion unit j3, and a high-voltage circuit breaker j4, wherein:

[0076] (1) The input terminal of the energy storage unit j1 is connected to the output terminal of the AC bus 1122 in the photovoltaic input main circuit 11, and its output terminal is connected to the input terminal of the DC-DC converter j2. When the total effective power of the photovoltaic is not less than the preset no-load threshold but less than the preset low-load threshold but the expected active power on the grid-connected side is not zero, the energy storage unit j1 discharges to drive the high-frequency conversion unit j3 of the solid-state transformer to work in the high-efficiency load range, so as to avoid the operating module j being in the low-load efficiency trough. When the total effective power of the photovoltaic is less than the preset no-load threshold (such as at night or on a cloudy day), the energy storage unit j1 discharges to maintain the necessary system support or grid auxiliary services by providing a small amount of active power, thereby eliminating the inherent no-load iron loss of the traditional step-up transformer.

[0077] (2) The DC-DC converter j2 converts the low-voltage DC (such as 400V or 800V) output by the energy storage power supply j1 into an intermediate DC power suitable for subsequent high-frequency input.

[0078] (3) The solid-state transformer high-frequency conversion unit j3 inverts the intermediate DC power output from the DC-DC converter j2 into high-voltage AC power that meets the grid connection requirements.

[0079] Figure 5 This is a schematic diagram of the structure of an optional solid-state transformer high-frequency conversion unit j3 according to an embodiment of this application, as shown below. Figure 5 As shown. The solid-state transformer high-frequency conversion unit j3 includes at least: a high-frequency inverter circuit j31, a high-frequency transformer j32, and a high-frequency rectifier circuit j33, wherein:

[0080] (3.1) The input terminal of the high-frequency inverter circuit j31 is connected to the output terminal of the DC-DC converter j2. It is used to convert the intermediate DC output of the DC-DC converter j2 into high-frequency AC through the high-frequency switching action of fully controlled power devices (such as insulated gate bipolar transistors, silicon carbide metal oxide semiconductor field-effect transistors, etc.) so that the subsequent high-frequency transformer j32 can perform voltage transformation and electrical isolation.

[0081] (3.2) The high-frequency transformer J32 is located between the high-frequency inverter circuit J31 and the high-frequency rectifier circuit J33. It consists of a primary winding and a secondary winding. The primary winding of the high-frequency transformer J32 is connected to the output terminal of the high-frequency inverter circuit J31 to receive high-frequency AC power; the secondary winding of the high-frequency transformer J32 is connected to the input terminal of the high-frequency rectifier circuit J33. It transforms the high-frequency AC power from low voltage to a voltage level suitable for subsequent rectification according to the turns ratio.

[0082] (3.3) The output terminal of the high-frequency rectifier circuit j33 is connected to the grid-connected main circuit 13, which converts the high-frequency AC power from the secondary winding of the high-frequency transformer j32 into high-voltage AC power through rectifier diodes or synchronous rectifier devices.

[0083] (4) The high-voltage circuit breaker j4 is used to realize the physical switching and safety isolation of the operating module j. Specifically, it can quickly close or open according to the instructions output by the controller 121 to connect the operating module j in series or bypass it from the high-voltage cascade chain. Therefore, it is the key execution unit to realize "modular redundancy" and "dynamic optimal matching". At the same time, when a fault occurs inside the operating module j or an abnormality is detected (such as overcurrent or short circuit), the connection between the operating module j and the grid-connected main circuit 13 is quickly switched to prevent the fault from spreading, ensure that other normally operating modules continue to operate, and improve the reliability of the entire system.

[0084] This application's embodiments, by designing a modular redundant architecture of parallel operating modules in the photovoltaic control system, allow for rapid disconnection of individual operating modules without affecting the overall system operation when a single operating module fails, significantly reducing the risk of unplanned downtime and operation and maintenance costs. Simultaneously, the parallel structure of multiple operating modules allows for dynamic adjustment of the number of modules in operation, ensuring the system always operates within a high-efficiency load range. This completely solves the problem of low efficiency of traditional single transformers under low-load or no-load conditions, and improves the system's ability to mitigate power fluctuations and the response speed of grid ancillary services, thereby comprehensively optimizing the investment returns throughout the power plant's entire lifecycle.

[0085] (III) The acquisition unit 125 serves as a distributed node within the switching control loop 12. Its input is connected to four key status monitoring points in the system, and its output is centrally connected to the controller 121. The specific connection relationship is as follows:

[0086] (1) Photovoltaic side input: connected to the output terminal of AC bus 1122 in the main photovoltaic input circuit 11 to collect the total active power of photovoltaic output by AC bus 1122 and provide the controller 121 with real-time data of current photovoltaic processing.

[0087] (2) Grid side input: The input terminal is connected to the grid bus in the grid main circuit 13 to collect the three-phase voltage on the grid bus and provide the grid side voltage status to the controller 121 to determine whether the grid side is normal and whether reactive power support or voltage regulation is required.

[0088] (3) Energy storage side input: connected to the output terminal of energy storage unit j1 in each group of operating modules j to collect energy storage data of energy storage unit j1, such as battery state of charge, health status or real-time charging and discharging power. The controller 121 can determine whether energy storage unit j1 has the ability to replenish energy or absorb power, thereby deciding whether to invest in additional modules or use energy storage to smooth out fluctuations.

[0089] (4) Transformer side input: Connected to the output terminal of the solid-state transformer high-frequency conversion unit j3 in each group of operating modules j, to collect module status data of the solid-state transformer high-frequency conversion unit j3, such as fault status, temperature, current, voltage, etc. The controller 121 can use this to determine which modules are available and which are faulty and need to be disconnected, thereby accurately calculating the actual number of modules that can be put into operation.

[0090] Optionally, Figure 6 This is a schematic diagram of an optional grid-connected main circuit 13 according to an embodiment of this application, as shown below. Figure 6 As shown, the grid-connected main circuit 13 includes at least: a grid-connected circuit breaker 131 and a grid-connected busbar 132, wherein:

[0091] The grid-connected circuit breaker 131 is installed between the output terminal of the three-phase high-voltage adapter 12i and the grid-connected bus 132. Its main functions include: according to the instructions of the controller 121, connecting or disconnecting the circuit during normal startup, shutdown, or dynamic module switching of the photovoltaic control system to realize the transmission or isolation of photovoltaic power to the grid; and tripping quickly when overcurrent, short circuit, ground fault, or grid abnormality (such as voltage exceeding limit or frequency deviation) is detected to disconnect the photovoltaic side from the grid and protect the photovoltaic equipment and grid safety. For example, the grid-connected circuit breaker 131 can be a vacuum circuit breaker or an SF6 circuit breaker, which can be selected according to the voltage level required in the actual scenario.

[0092] The grid-connected busbar 132 is part of the distribution network and is located upstream of the grid-connected circuit breaker 131. Its main functions include: serving as a point of common connection, collecting photovoltaic power and distributing it to other loads or lines in the distribution network; and providing a stable three-phase voltage so that the photovoltaic control system can use this as a reference for synchronous grid connection. Generally, the grid-connected busbar 132 uses copper or aluminum busbars, which have high conductivity and sufficient mechanical strength to withstand the thermal and electrodynamic effects of rated current and short-circuit current. At the same time, the grid-connected busbar 132 can be fixed in the substation structure or switchgear by insulators (such as epoxy resin insulators or porcelain insulators) to ensure insulation to ground and between phases.

[0093] Therefore, the grid-connected circuit breaker in the grid-connected main circuit 13 acts as a "switch" to control the on / off state and protection of photovoltaic power, while the grid-connected bus 132 acts as a "channel" to provide the physical basis and electrical environment for power to be connected to the grid.

[0094] It should be noted that, for the sake of simplicity, the aforementioned commissioning control method executed by the controller is described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0095] Through the above description of the embodiments, those skilled in the art can clearly understand that the commissioning control method executed by the above controller can be implemented by means of software plus necessary general-purpose hardware platform. Of course, it 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 prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as read-only memory (ROM) / random access memory (RAM), magnetic disk, optical disk), and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods of the various embodiments of this application.

[0096] According to another aspect of the embodiments of this application, a computer-readable storage medium is provided, the computer-readable storage medium including a stored program, wherein the program executes the commissioning control method implemented by the controller described above when it runs.

[0097] In one exemplary embodiment, the aforementioned computer-readable storage medium may include, but is not limited to, various media capable of storing computer programs, such as USB flash drives, ROMs, RAMs, portable hard drives, magnetic disks, or optical disks.

[0098] According to another aspect of the embodiments of this application, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor is configured to execute the commissioning control method implemented by the controller described above through the computer program.

[0099] In one exemplary embodiment, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor and the input / output device is connected to the processor.

[0100] Specific examples in this embodiment can be found in the examples described in the above embodiments and exemplary implementations, and will not be repeated here.

[0101] As an optional implementation method, Figure 7 A block diagram of an optional controller is shown. (For example...) Figure 7 As shown, the controller 70 may include a processor 702, a memory 704 for storing data, and a transmission device 706 for communication functions. The processor 702 may include one or more processors. For ease of explanation, Figure 7 The diagram illustrates multiple processors, including a first processor 7012ia, a second processor 7012ib, ..., an nth processor 7012iN12iN. Processor 702 may be a processing device including, but not limited to, a microprocessor (MCU) or a programmable gate array (FPGA).

[0102] In addition, the controller 70 may also include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of a BUS bus), a network interface, a power supply, and / or a camera. Those skilled in the art will understand that... Figure 7 The structure shown is for illustrative purposes only and does not limit the structure of the controller described above. For example, controller 70 may also include a... Figure 7 The more or fewer components shown, or having the same Figure 7 The different configurations shown.

[0103] Processor 702 may include one or more processing units. For example, processor 702 may include processing devices such as central processing unit (CPU), graphics processing unit (GPU), digital signal processing (DSP) chip, microcontroller unit (MCU), field-programmable gate array (FPGA), neural network processing unit (NPU), tensor processing unit (TPU), artificial intelligence (AI) type processor, etc. Different processing units may be independent components or integrated into one or more processors.

[0104] It should be noted that the aforementioned one or more processors 702 and / or other data processing circuitry are generally referred to herein as "data processing circuitry". This data processing circuitry may be embodied, in whole or in part, in software, hardware, firmware, or any other combination thereof. Furthermore, the data processing circuitry may be a single, independent processing module, or may be integrated, in whole or in part, into any other element within the controller 70. As involved in the embodiments of this application, this data processing circuitry serves as a processor control mechanism (e.g., selection of a variable resistor termination path connected to an interface).

[0105] The memory 704 can be used to store software programs and modules of application software, such as the program instructions / data storage device corresponding to the commissioning control method applied to the controller in this embodiment of the application. The processor 702 executes various functional applications and data processing by running the software programs and modules stored in the memory 704, thereby realizing the above-mentioned commissioning control method applied to the controller. The memory 704 may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 704 may further include memory remotely located relative to the processor 702, and these remote memories can be connected to the controller 70 via a network. Examples of the above-mentioned networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0106] The transmission device 706 is used to receive or send data via a network. Specific examples of the network described above may include a wireless network provided by the communication provider of the controller 70. In one example, the transmission device 706 includes a Network Interface Controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the transmission device 706 may be a Radio Frequency (RF) module, used for data interaction with external networks or devices via wired and / or wireless network connections.

[0107] The display can be, for example, a liquid crystal display (LCD) or a touchscreen display (also known as a "touchscreen" or "touch display screen"). This LCD allows the user to interact with the user interface of the mobile terminal. Furthermore, the controller 70 can connect to a cursor control device and a keyboard via an input / output interface. The cursor control device (e.g., a mouse, trackball, or touchpad) is primarily used to transmit directional information and command selections to the terminal and control the movement of the cursor on the display; the keyboard is primarily used to receive letters, numbers, and other control commands input by the user, thereby enabling interaction between the user and the controller 70.

[0108] It should be noted here that, in some optional embodiments, the above... Figure 7 The controller shown may include hardware elements (including circuitry), software elements (including computer code stored on a computer-readable medium), or a combination of both hardware and software elements. It should be noted that... Figure 7 This is only one instance of a specific instance and is intended to illustrate the types of components that can exist in the controller described above.

[0109] Obviously, those skilled in the art should understand that the modules or steps of this application described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. They can be implemented using computer-executable program code, and thus can be stored in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those described herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, this application is not limited to any particular combination of hardware and software.

[0110] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this application should be included within the protection scope of this application.

Claims

1. A photovoltaic control system, characterized in that, The photovoltaic control system includes at least: a photovoltaic input main circuit, a switching control circuit, and a grid-connected main circuit. The switching control circuit includes at least: a controller and a three-phase high-voltage adapter disposed between the photovoltaic input main circuit and the grid-connected main circuit. Each phase high-voltage adapter includes at least one set of operating modules, and each set of operating modules includes at least: an energy storage unit and a solid-state transformer high-frequency conversion unit. The controller is used to determine the target number of operating modules to be turned on based on the total active power of photovoltaic input main circuit output, the operating status data of multiple operating modules in the switching control circuit, and the three-phase voltage value of grid-connected side output by grid-connected main circuit, and to send control commands carrying the target number to the three-phase high-voltage adapter.

2. The photovoltaic control system according to claim 1, characterized in that, The photovoltaic input main circuit includes at least: multiple inverters and an AC combiner module, wherein, The input terminals of the plurality of inverters are connected to the photovoltaic array, and the output terminals of the plurality of inverters are connected to the input terminal of the AC combiner module; The AC busbar module includes at least a low-voltage circuit breaker and an AC busbar, wherein the input terminal of the low-voltage circuit breaker is connected to the output terminal of the plurality of inverters, the output terminal of the low-voltage circuit breaker is connected to the input terminal of the AC busbar, and the output terminal of the AC busbar is connected to the input terminal of the switching control circuit.

3. The photovoltaic control system according to claim 2, characterized in that, Each of the aforementioned operating modules further includes: a DC-DC converter and a high-voltage circuit breaker, wherein, The input terminal of the energy storage unit is connected to the output terminal of the AC busbar in the photovoltaic input main circuit, and the output terminal of the energy storage unit is connected to the input terminal of the DC-DC converter. The input terminal of the solid-state transformer high-frequency conversion unit is connected to the output terminal of the DC-DC converter, and the output terminal of the solid-state transformer high-frequency conversion unit is connected to the input terminal of the three-phase high-voltage adapter. The input terminal of the high-voltage circuit breaker is connected to the output terminal of the three-phase high-voltage adapter, and the output terminal of the high-voltage circuit breaker is connected to the grid-connected main circuit.

4. The photovoltaic control system according to claim 1, characterized in that, The grid-connected main circuit includes at least: a grid-connected circuit breaker and a grid-connected bus, wherein the grid-connected circuit breaker is disposed between the output terminal of the high-voltage circuit breaker and the grid-connected bus.

5. The photovoltaic control system according to claim 1, characterized in that, The switching control loop further includes a data acquisition unit, wherein the operating status data includes at least the energy storage data of the energy storage unit and the module status data of the solid-state transformer high-frequency conversion unit. The input terminal of the acquisition unit is connected to the output terminal of the AC bus in the photovoltaic input main circuit, the input terminal of the grid-connected bus in the grid-connected main circuit, the output terminal of the energy storage unit in each group of the operating modules, and the output terminal of the solid-state transformer high-frequency conversion unit. The output terminal of the acquisition unit is connected to the input terminal of the controller and is used to send the acquired total photovoltaic active power, grid-connected three-phase voltage value, energy storage data of the energy storage unit in each group of the operating modules, and module status data of the solid-state transformer high-frequency conversion unit to the controller. The output terminal of the controller is connected to the input terminal of the three-phase high-voltage adapter. It is used to determine the target operating mode based on the total active power of the photovoltaic system, the three-phase voltage value on the grid-connected side, and the energy storage data of each energy storage unit. Based on the target operating mode, the three-phase voltage value on the grid-connected side, the total active power of the photovoltaic system, the energy storage data of each energy storage unit, and the module status data of each group of operating modules, it determines the target quantity and sends a control command carrying the target quantity to control the three-phase high-voltage adapter.

6. The photovoltaic control system according to claim 5, characterized in that, The energy storage data includes at least: battery state of charge; Based on the total active power of the photovoltaic system, the three-phase voltage values ​​on the grid-connected side, and the energy storage data of each energy storage unit, the target operating mode is determined, including: Based on the relationship between the total photovoltaic active power and the preset power threshold, the photovoltaic output level is determined, wherein the photovoltaic output level includes at least: no-load level or low-load level; Based on the relationship between the three-phase voltage values ​​on the grid-connected side and the preset upper limit and lower limit of the grid-connected voltage, the grid-connected voltage status is determined, wherein the grid-connected voltage status includes: normal status or over-limit status. Based on the battery state of charge of each energy storage unit and the preset maximum available state of charge threshold and the preset minimum available state of charge threshold, the energy storage scheduling state is determined, wherein the energy storage scheduling state includes: charging state or discharging state. The target operating mode that matches the photovoltaic output level, the grid connection voltage state and the energy storage dispatch state is determined from the preset operating mode logic table. The operating mode logic table includes the photovoltaic output level, grid connection voltage state and energy storage dispatch state corresponding to each of the various operating modes.

7. The photovoltaic control system according to claim 6, characterized in that, Determining a target operating mode that matches the photovoltaic output level, the grid connection voltage state, and the energy storage dispatch state from a preset operating mode logic table includes: When the grid-connected voltage state is in an over-limit state, the target operating mode is determined to be the reactive power support mode; When the grid-connected voltage is in a normal state, the photovoltaic output level is at the no-load level, and the energy storage dispatch state is in the charging state, the target operating mode is determined to be the energy storage stabilization mode. When the grid-connected voltage is in a normal state, the photovoltaic output level is in a low-load state, and the energy storage dispatch state is in a discharge state, the target operating mode is determined to be a high-efficiency power generation mode. When the grid-connected voltage is in a normal state and the photovoltaic output level is at the no-load level, the target operating mode is determined to be the idle standby mode.

8. The photovoltaic control system according to claim 5, characterized in that, The module status data includes at least: status data of the solid-state transformer high-frequency conversion unit; Based on the target operating mode, the grid-connected three-phase voltage value, the total photovoltaic active power, the energy storage data of each energy storage unit, and the module status data of each group of operating modules, the target quantity is determined, including: The set of available operating modules is determined based on the status data of the solid-state transformer high-frequency conversion unit in each of the operating modules, and the total number of modules in the set of available operating modules is determined. Based on the target operating mode, the three-phase voltage value on the grid-connected side, the total active power of photovoltaics, the energy storage data of each energy storage unit, and the module status data of each group of operating modules, the theoretical number of modules corresponding to the target operating mode is determined. Compare the number of theoretical modules with the total number of modules in the set of available running modules; If the number of theoretical modules is not greater than the total number of modules, the number of theoretical modules shall be taken as the target number; If the number of theoretical modules is greater than the total number of modules, the total number of modules shall be used as the target number.

9. The photovoltaic control system according to claim 7, characterized in that, The energy storage data also includes: maximum charging and discharging power; the module status data also includes: maximum reactive power output and minimum active power required to be in the optimal efficiency range. Based on the target operating mode, the grid-connected three-phase voltage value, the total photovoltaic active power, the energy storage data of each energy storage unit, and the module status data of each group of operating modules, the theoretical number of modules corresponding to the target operating mode is determined, including: When the target operating mode is the reactive power support mode, the target reactive power is determined based on the three-phase voltage value on the grid side, and the quotient obtained by dividing the target reactive power by the average value of the maximum reactive power output power of all operating modules is rounded up to obtain the theoretical number of modules. When the target operating mode is the energy storage smoothing mode, the predicted value of the total photovoltaic active power of the photovoltaic array is determined based on the historical total photovoltaic active power sequence of the photovoltaic array and real-time meteorological monitoring data. The total energy storage charging and discharging power of all energy storage units is determined by combining the preset smoothing control algorithm. The quotient of the total energy storage charging and discharging power divided by the maximum charging and discharging power of the energy storage unit is rounded up to obtain the theoretical number of modules. When the target operating mode is the high-efficiency power generation mode, the quotient obtained by dividing the total photovoltaic active power by the average of the minimum active power of all operating modules is rounded up to obtain the number of basic modules, and the number of energy storage units in the preset state of charge range and in the discharge state is determined; when the number of basic modules is less than the number of energy storage units, the number of auxiliary support modules is determined to be the number of basic modules; when the number of basic modules is not less than the number of energy storage units, the number of auxiliary support modules is determined to be zero; the sum of the number of basic modules and the number of auxiliary support modules is taken as the theoretical number of modules. When the target operating mode is the idle standby mode, the theoretical number of modules is determined to be zero.

10. The photovoltaic control system according to claim 7, characterized in that, Sending control commands carrying the target quantity to control the three-phase high-voltage adapter includes: When the target operating mode is the idle standby mode, a first control command is sent to the three-phase high-voltage adapter, wherein the first control command is used to instruct the operation of all operating modules in the three-phase high-voltage adapter to be suspended; When the target operating mode is the reactive power support mode, the energy storage stabilization mode, or the high-efficiency power generation mode, a second control command is sent to the three-phase high-voltage adapter, wherein the second control command is used to instruct the control of a target number of operating modules in the three-phase high-voltage adapter to start operation.

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