Power compensation control method and device, controller and optical storage hybrid system

Abstract

The invention provides a power compensation control method and device, a controller and an optical storage hybrid system, and relates to the technical field of electric power. The optical storage hybrid system comprises a multi-phase optical storage hybrid unit, each phase optical storage hybrid unit comprises a plurality of photovoltaic units and a plurality of energy storage units, the plurality of photovoltaic units and the plurality of energy storage units are connected in series to a power grid, and the method can comprise the following steps: controlling all the photovoltaic units of the multi-phase optical storage hybrid unit to work in a maximum power point tracking mode; obtaining the output power of the plurality of photovoltaic units of each phase of light storage mixing unit and the charge state and the power compensation state of the plurality of energy storage units of each phase of light storage mixing unit; and according to the output power of the plurality of photovoltaic units and the charge states and the power compensation states of the plurality of energy storage units, the working modes of the plurality of photovoltaic units and the working modes of the plurality of energy storage units are controlled, so that the generated power of the multi-phase light storage mixing unit is equal. According to the invention, multi-phase equal power output of the optical storage hybrid system can be realized.

Description

Technical Field

[0001] This application relates to the field of power technology, and more specifically, to a power compensation control method, device, controller, and photovoltaic-storage hybrid system. Background Technology

[0002] Three-phase cascaded photovoltaic systems are expected to become the preferred topology for next-generation centralized photovoltaic grid-connected inverters due to their superior performance.

[0003] Because a three-phase cascaded photovoltaic system integrates multiple independent photovoltaic modules on the DC side, the power generation of each module varies due to environmental factors and differences in the characteristics of the modules and power electronic equipment. To achieve symmetrical output of the three-phase grid-connected current, the zero-sequence voltage injection method is widely used for phase-to-phase power equalization control in three-phase cascaded photovoltaic systems.

[0004] However, after zero-sequence voltage injection, the modulation factor of the power unit in the generator increases, posing a risk of overmodulation. Overmodulation will cause grid-connected current distortion, which can seriously affect the stable operation of the system. In addition, the calculation process of zero-sequence voltage is relatively complex, which is not conducive to the implementation of digital controllers. Summary of the Invention

[0005] The purpose of this application is to address the shortcomings of the prior art by providing a power compensation control method, device, controller, and photovoltaic-storage hybrid system, so as to achieve multi-phase equal power output of the photovoltaic-storage hybrid system.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows: In a first aspect, embodiments of this application provide a power compensation control method for a photovoltaic-storage hybrid system. The photovoltaic-storage hybrid system includes a multi-phase photovoltaic-storage hybrid unit, each phase photovoltaic-storage hybrid unit including: multiple photovoltaic units and multiple energy storage units, the multiple photovoltaic units and the multiple energy storage units being connected in series to the power grid. The method includes: Control all photovoltaic units of the multiphase photovoltaic-storage hybrid unit to operate in maximum power point tracking mode; The output power of multiple photovoltaic units in each phase photovoltaic-storage hybrid unit and the state of charge and power compensation status of multiple energy storage units in each phase photovoltaic-storage hybrid unit are obtained. Based on the output power of the multiple photovoltaic units, the state of charge and power compensation state of the multiple energy storage units, the operating modes of the multiple photovoltaic units and the multiple energy storage units are controlled to ensure that the power generation of the multiphase photovoltaic-energy storage hybrid unit is equal.

[0007] Optionally, controlling the operating modes of the multiple photovoltaic units and the multiple energy storage units based on the output power of the multiple photovoltaic units, the state of charge of the multiple energy storage units, and the power compensation state of the multiple energy storage units includes: Based on the output power of the plurality of photovoltaic units and the output power of all photovoltaic units, calculate the photovoltaic output power difference and photovoltaic power operating point of each phase photovoltaic-storage hybrid unit; Calculate the average state of charge of each phase photovoltaic-storage hybrid unit based on the state of charge of the plurality of energy storage units; Based on the photovoltaic output power difference, photovoltaic power operating point, average state of charge, and power compensation status of each photovoltaic-storage hybrid unit, the operating modes of the multiple photovoltaic units and the multiple energy storage units are controlled.

[0008] Optionally, controlling the operating modes of the multiple photovoltaic units and the multiple energy storage units based on the photovoltaic output power difference of each phase photovoltaic-energy storage hybrid unit, the photovoltaic power operating point, the average state of charge, and the power compensation status of the multiple energy storage units includes: When the power compensation state of the plurality of energy storage units is enabled, if the difference in photovoltaic output power is not zero, the operating mode of the plurality of energy storage units is determined to be charging mode, discharging mode or deactivation mode based on the average state of charge. Based on the relationship between the photovoltaic power operating point and the maximum photovoltaic power operating point of each phase photovoltaic-storage hybrid unit, it is determined whether the multiple photovoltaic units should exit the maximum power point tracking mode.

[0009] Optionally, the method further includes: If the power compensation status of the plurality of energy storage units is enabled and the difference in photovoltaic output power is zero, then the operating mode of the plurality of energy storage units is determined to be the shutdown mode.

[0010] Optionally, the method further includes: If the multiple energy storage units are operating in charging mode, the input power of each energy storage unit is calculated using the first calculation method based on the photovoltaic output power difference and the state of charge of each energy storage unit. If the multiple energy storage units operate in discharge mode, the output power of each energy storage unit is calculated using a second calculation method based on the photovoltaic output power difference and the state of charge of each energy storage unit.

[0011] Optionally, controlling the operating modes of the multiple photovoltaic units and the multiple energy storage units based on the photovoltaic output power difference of each phase photovoltaic-energy storage hybrid unit, the photovoltaic power operating point, the average state of charge, and the power compensation status of the multiple energy storage units includes: When the power compensation status of the plurality of energy storage units is off, the working mode of the plurality of energy storage units is determined to be charging mode, discharging mode or exit mode based on the relationship between the average state of charge and the preset state of charge, the relationship between the photovoltaic power operating point and the maximum photovoltaic power operating point of each phase photovoltaic-storage hybrid unit, and whether the plurality of photovoltaic units exit the maximum power point tracking mode.

[0012] Optionally, the method further includes: If the working mode of the plurality of energy storage units is charging mode, the input power of each energy storage unit is calculated using a third calculation method based on the maximum operating point of the hybrid power of each phase photovoltaic-energy storage hybrid unit, the sum of the rated power of all photovoltaic units, the sum of the rated power of all energy storage units, the sum of the output power of the plurality of photovoltaic units, and the state of charge of each energy storage unit. If the multiple energy storage units operate in discharge mode, the output power of each energy storage unit is calculated using a fourth calculation method based on the maximum operating point of the hybrid power of each phase photovoltaic-energy storage unit, the sum of the rated power of all photovoltaic units, the sum of the rated power of all energy storage units, the sum of the output power of the multiple photovoltaic units, and the state of charge of each energy storage unit.

[0013] Secondly, embodiments of this application also provide a power compensation control device for a photovoltaic-storage hybrid system. The photovoltaic-storage hybrid system includes a multi-phase photovoltaic-storage hybrid unit, each phase photovoltaic-storage hybrid unit including: multiple photovoltaic units and multiple energy storage units, the multiple photovoltaic units and the multiple energy storage units being connected in series to the power grid, and the device including: The control module is used to control all photovoltaic units of the multiphase photovoltaic-storage hybrid unit to operate in maximum power point tracking mode; The parameter acquisition module is used to acquire the output power of multiple photovoltaic units in each phase photovoltaic-storage hybrid unit and the state of charge and power compensation status of multiple energy storage units in each phase photovoltaic-storage hybrid unit. The control module is further configured to control the operating modes of the multiple photovoltaic units and the multiple energy storage units based on the output power of the multiple photovoltaic units, the state of charge of the multiple energy storage units, and the power compensation state, so as to make the power generation of the multiphase photovoltaic-energy storage hybrid unit equal.

[0014] Optionally, the control module is specifically configured to calculate the photovoltaic output power difference and photovoltaic power operating point of each phase photovoltaic-storage hybrid unit based on the output power of the plurality of photovoltaic units and the output power of all photovoltaic units; calculate the average state of charge of each phase photovoltaic-storage hybrid unit based on the state of charge of the plurality of energy storage units; and control the operating modes of the plurality of photovoltaic units and the plurality of energy storage units based on the photovoltaic output power difference, photovoltaic power operating point, average state of charge, and power compensation status of each phase photovoltaic-storage hybrid unit.

[0015] Optionally, the control module is specifically configured to, when the power compensation state of the plurality of energy storage units is enabled, if the difference in photovoltaic output power is not zero, determine the operating mode of the plurality of energy storage units as charging mode, discharging mode, or exit mode based on the average state of charge; and determine whether the plurality of photovoltaic units exit the maximum power point tracking mode based on the relationship between the photovoltaic power operating point and the maximum photovoltaic power operating point of each phase photovoltaic-storage hybrid unit.

[0016] Optionally, the control module is further configured to determine that the operating mode of the plurality of energy storage units is the exit mode when the power compensation state of the plurality of energy storage units is enabled and the difference in photovoltaic output power is zero.

[0017] Optionally, the control module is further configured to: if the operating mode of the plurality of energy storage units is charging mode, calculate the input power of each energy storage unit using a first calculation method based on the photovoltaic output power difference and the state of charge of each energy storage unit; if the operating mode of the plurality of energy storage units is discharging mode, calculate the output power of each energy storage unit using a second calculation method based on the photovoltaic output power difference and the state of charge of each energy storage unit.

[0018] Optionally, the control module is further configured to, when the power compensation state of the plurality of energy storage units is off power compensation, determine the operating mode of the plurality of energy storage units as charging mode, discharging mode or exit mode based on the relationship between the average state of charge and the preset state of charge, the relationship between the photovoltaic power operating point and the maximum photovoltaic power operating point of each phase photovoltaic-storage hybrid unit, and determine whether the plurality of photovoltaic units exit the maximum power point tracking mode.

[0019] Optionally, the control module is further configured to, if the multiple energy storage units are operating in charging mode, calculate the input power of each energy storage unit using a third calculation method based on the maximum operating point of the hybrid power of each phase photovoltaic-energy storage hybrid unit, the sum of the rated power of all photovoltaic units, the sum of the rated power of all energy storage units, the sum of the output power of the multiple photovoltaic units, and the state of charge of each energy storage unit; and if the multiple energy storage units are operating in discharging mode, calculate the output power of each energy storage unit using a fourth calculation method based on the maximum operating point of the hybrid power of each phase photovoltaic-energy storage hybrid unit, the sum of the rated power of all photovoltaic units, the sum of the rated power of all energy storage units, the sum of the output power of the multiple photovoltaic units, and the state of charge of each energy storage unit.

[0020] Thirdly, embodiments of this application also provide a controller, which is connected to the control terminals of all photovoltaic units and all energy storage units in the photovoltaic-energy storage hybrid system. The controller executes the steps of the power compensation control method as described in any of the first aspects to perform power compensation on the multiphase photovoltaic-energy storage hybrid units of the photovoltaic-energy storage hybrid system.

[0021] Fourthly, embodiments of this application also provide a photovoltaic-storage hybrid system, the photovoltaic-storage hybrid system comprising a multiphase photovoltaic-storage hybrid unit, each phase photovoltaic-storage hybrid unit comprising: multiple photovoltaic units and multiple energy storage units, each photovoltaic unit having a photovoltaic module connected to its DC side, each energy storage unit having a battery module connected to its DC side, each photovoltaic unit having a bypass switch connected in parallel to its AC side, the multiple photovoltaic units and the multiple energy storage units having their AC sides connected in series to the power grid, and the photovoltaic-storage hybrid system employing the power compensation control method as described in any of the first aspects for power compensation.

[0022] The beneficial effects of this application are: The power compensation control method, device, controller, and photovoltaic-storage hybrid system provided in this application, by adding energy storage units to the photovoltaic power generation system, controls the operating modes of multiple photovoltaic units and multiple energy storage units based on the output power of multiple photovoltaic units, the state of charge of multiple energy storage units, and the power compensation state. The energy storage units compensate for the power generation of the photovoltaic units, ensuring consistent power generation across the multi-phase photovoltaic-storage hybrid system. This scheme reduces the complexity of inter-phase power balance control, expands the operating boundaries of the photovoltaic-storage hybrid system, and achieves high-quality grid-connected current output, maximum power generation efficiency of photovoltaic units, and autonomous and safe operation of the energy storage units' state of charge. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a topology diagram of the photovoltaic-storage hybrid system provided in the embodiments of this application; Figure 2 A flowchart illustrating the power compensation control method provided in the embodiments of this application. Figure 1 ; Figure 3 A flowchart illustrating the power compensation control method provided in the embodiments of this application. Figure 2 ; Figure 4 A flowchart illustrating the power compensation control method provided in the embodiments of this application. Figure 3 ; Figure 5 Equivalent circuit diagram of a time-storage hybrid system for charging an energy storage unit provided in the embodiments of this application; Figure 6 An equivalent circuit diagram of the energy storage unit exiting the time-storage hybrid system provided in the embodiments of this application; Figure 7 An equivalent circuit diagram of a time-storage hybrid system provided in the embodiments of this application during energy storage unit discharge; Figure 8 A flowchart illustrating the power compensation control method provided in an embodiment of this application; Figure 9 This is a schematic diagram of the power compensation control device provided in an embodiment of this application. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0026] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0027] Furthermore, the terms "first," "second," etc., used in the specification, claims, and accompanying 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. Additionally, the terms "comprising" and "having," and any variations thereof, are intended to cover a 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.

[0028] It should be noted that, where there is no conflict, the features in the embodiments of this application can be combined with each other.

[0029] To better understand the power compensation control method provided in this solution, the following section will first introduce the photovoltaic-storage hybrid system targeted by this application.

[0030] Figure 1 A topology diagram of the photovoltaic-storage hybrid system provided in the embodiments of this application is shown below. Figure 1 As shown, the photovoltaic-storage hybrid system may include a multiphase photovoltaic-storage hybrid unit 10. Each phase photovoltaic-storage hybrid unit 10 includes: multiple photovoltaic units and multiple energy storage units. The DC side of each photovoltaic unit is connected to a photovoltaic module, and the DC side of each energy storage unit is connected to a battery module. The AC side of each photovoltaic unit and the AC side of each photovoltaic unit are connected in parallel with a bypass switch. The AC sides of multiple photovoltaic units and multiple energy storage units are connected in series to the power grid.

[0031] In this embodiment, as Figure 1 As shown, the multiphase photovoltaic-storage hybrid unit 10 may include a , b , c Each of the three-phase, photovoltaic-storage hybrid units consists of n photovoltaic units and k energy storage units. Each photovoltaic unit comprises a power transistor. S iPj1 ~ S iPj4 The full-bridge circuit and capacitors C iPj Photovoltaic modules V PVij and bypass switch K iPj Composition: Each energy storage unit consists of power transistors. S iBj1 ~ S iBj4 The full-bridge circuit and capacitors C iBjBattery module V Bij and bypass switch K iBj The components and their connections are shown in the figure, which will not be elaborated here.

[0032] The controller connects to the control terminals of the bypass switches of all photovoltaic units and all energy storage units, controlling the opening and closing of the bypass switches. When the bypass switch is open, the corresponding photovoltaic unit or energy storage unit provides energy to the grid. When the bypass switch is closed, the corresponding photovoltaic unit or energy storage unit is shut down, and energy cannot be transferred to the AC grid.

[0033] In some embodiments, the multiple photovoltaic units and multiple energy storage units of each phase photovoltaic-storage hybrid unit 10 are connected in series with an AC filter inductor L and then connected to the power grid.

[0034] In some embodiments, the controller connects to the gates of the power transistors of all photovoltaic units and all energy storage units to control the photovoltaic units to operate in maximum power point tracking mode or exit maximum power point tracking mode, and to control the energy storage units to operate in charging mode, discharging mode, or exit mode.

[0035] The specific implementation of the power compensation control method provided in this application will be described below with reference to the embodiments.

[0036] Figure 2 A flowchart illustrating the power compensation control method provided in the embodiments of this application. Figure 1 ,like Figure 2 As shown, the method may include: S101, Control all photovoltaic units of the multiphase photovoltaic-storage hybrid unit to operate in maximum power point tracking mode.

[0037] In this embodiment, the Maximum Power Point Tracking (MPPT) mode is used to indicate that the operating voltage of the photovoltaic unit is stable near the maximum power point voltage. The specific control method can be as follows: real-time detection of the output voltage and output current of the photovoltaic module in the photovoltaic unit; calculation of the current power based on the output voltage and output current using a preset MPPT algorithm; determination of the optimal operating voltage based on the current power and the maximum output power; calculation of the voltage error based on the optimal operating voltage and the output voltage; calculation of the current reference value based on the voltage error; calculation of the current reference value and the output voltage; generation of the PWM control signal for the full-bridge circuit based on the current error to control the switching state of the power transistors in the full-bridge circuit, thereby adjusting the output current of the photovoltaic module so that the operating voltage of the photovoltaic unit is stable near the maximum power point voltage.

[0038] In some embodiments, since each photovoltaic unit has certain differences, its maximum power point voltage may be different. A slave controller can be set up for each photovoltaic unit, and all slave controllers are connected to a master controller. The master controller sends control commands for maximum power point tracking mode to each slave controller. Each slave controller performs individual calculations and controls for each photovoltaic unit according to the control commands for maximum power point tracking mode.

[0039] The maximum power point voltage of each photovoltaic unit can be determined by testing the current-voltage curve of the photovoltaic module.

[0040] S102. Obtain the output power of multiple photovoltaic units in each phase photovoltaic-storage hybrid unit and the state of charge and power compensation status of multiple energy storage units in each phase photovoltaic-storage hybrid unit.

[0041] In this embodiment, the energy storage unit in the photovoltaic-storage hybrid system is used to compensate the output power of the photovoltaic unit so that the power generation provided to the grid by the multi-phase photovoltaic-storage hybrid unit is equal. Therefore, it is necessary to determine whether the output power of the photovoltaic unit in each photovoltaic-storage hybrid unit needs to be compensated based on the output power of the multiple photovoltaic units in each phase photovoltaic-storage hybrid unit.

[0042] It should be noted that compensation for the output power of the photovoltaic unit includes absorbing excess energy from the photovoltaic unit or compensating for insufficient energy in the photovoltaic unit.

[0043] When compensating for the output power of photovoltaic (PV) units, an energy storage unit is required. The power compensation status of the energy storage unit indicates whether power compensation is enabled. When power compensation is needed for the PV-energy storage hybrid system, the energy storage unit's power compensation can be enabled. When the energy storage unit's power compensation status is enabled, it can compensate for the output power of the PV units. When power compensation is not needed for the PV-energy storage hybrid system, the energy storage unit's power compensation can be disabled.

[0044] When power compensation is enabled, it is necessary to determine whether the state of charge of the energy storage unit supports power compensation for the photovoltaic unit based on the state of charge of the energy storage unit.

[0045] In some embodiments, the power compensation state of multiple energy storage units in each phase of the photovoltaic-energy storage hybrid unit is uniformly controlled. That is, the power compensation state of energy storage units in different phases of the photovoltaic-energy storage hybrid unit may be different, but the power compensation state of multiple energy storage units in the same photovoltaic-energy storage hybrid unit must be consistent.

[0046] S103. Based on the output power of multiple photovoltaic units, the state of charge and power compensation status of multiple energy storage units, control the operating modes of multiple photovoltaic units and multiple energy storage units to ensure that the power generation of the multiphase photovoltaic-energy storage hybrid unit is equal.

[0047] In this embodiment, it is first determined whether power compensation is enabled for the multiple energy storage units in each phase of the photovoltaic-storage hybrid unit. If power compensation is enabled, the power generation of the multi-phase photovoltaic-storage hybrid unit is determined based on the output power of the multiple photovoltaic units. If the power generation is unequal, it is determined whether the multiple photovoltaic units in each phase of the photovoltaic-storage hybrid unit can continue to operate in maximum power point tracking mode to ensure grid voltage safety. Furthermore, based on the output power of the multiple photovoltaic units in each phase of the photovoltaic-storage hybrid unit and the state of charge of the multiple energy storage units, the operating mode of the multiple energy storage units is determined to be charging mode, power generation mode, or deactivation mode.

[0048] Among them, the charging mode is used to absorb the excess energy output by the photovoltaic unit of the corresponding phase, the discharging mode is used to compensate for the insufficient energy of the photovoltaic unit of the corresponding phase, and the exit mode is used to indicate that it will not participate in the energy absorption or energy replenishment of the photovoltaic unit.

[0049] In some embodiments, the charging mode and discharging mode can be determined by controlling the conduction direction of the bridge arm of the full-bridge circuit of the energy storage unit, and the exit mode can be determined by controlling the closing of the bypass switch of the energy storage unit, or by controlling the output power of the energy storage unit to be 0.

[0050] In one possible implementation, Figure 3 A flowchart illustrating the power compensation control method provided in the embodiments of this application. Figure 2 ,like Figure 3 As shown, S103 controls the operating modes of the multiple photovoltaic units and the multiple energy storage units based on the output power of the multiple photovoltaic units, the state of charge of the multiple energy storage units, and the power compensation state of the multiple energy storage units, including: S201. Based on the output power of multiple photovoltaic units and the output power of all photovoltaic units, calculate the photovoltaic output power difference and power operating point of each phase photovoltaic-storage hybrid unit.

[0051] In this embodiment, for each phase photovoltaic-storage hybrid unit, the sum of the output power of the n photovoltaic units is calculated. P PVi Based on the sum of the output power of n photovoltaic units in the multiphase photovoltaic-storage hybrid unit P PVi Calculate the average output power of the multiphase photovoltaic unit. PPVavg Based on the sum of the output power of the n photovoltaic units in each phase photovoltaic-storage hybrid unit P PVi and the average output power of multiphase photovoltaic units P PVavg Calculate the difference in photovoltaic output power for each phase of the photovoltaic-storage hybrid unit. P Di ( i = a , b , c ).

[0052] For example, the sum of the output power of each of the n photovoltaic units in each phase. P PVi The calculation formula can be expressed as:

[0053] in, P PVij Indicates the first i ( i=a , b , c The first phase of the photovoltaic-storage hybrid unit j ( j=1 , 2 , … , n The output power of each photovoltaic unit.

[0054] Average output power of multiphase photovoltaic units P PVavg The calculation formula can be expressed as:

[0055] The output power difference of n photovoltaic units in each phase photovoltaic-storage hybrid unit P Di The calculation formula can be expressed as:

[0056] Based on the sum of the output power of each of the n photovoltaic units P PVi The sum of the rated power of all 3n photovoltaic units in the photovoltaic-storage hybrid system P PVR Calculate the photovoltaic power operating point of each phase photovoltaic-storage hybrid unit. X PVi [ X PVa ，X PVb ，X PVc Photovoltaic power operating point XPVi This represents the proportion of the n photovoltaic units in each phase of the photovoltaic-storage hybrid unit in the maximum output energy of the photovoltaic-storage hybrid system.

[0057] Example: Photovoltaic power operating point of each phase photovoltaic-storage hybrid unit X PVi The calculation formula can be expressed as:

[0058] S202. Calculate the average state of charge of each phase photovoltaic-storage hybrid unit based on the state of charge of multiple energy storage units.

[0059] In this embodiment, for each phase of the photovoltaic-storage hybrid unit, the average state of charge of k energy storage units is calculated. SOC iavg ( i = a , b , c ).

[0060] Example, average state of charge SOC iavg The calculation formula can be expressed as:

[0061] in, SOC ij Indicates the first i ( i=a , b , c The first phase of the photovoltaic-storage hybrid unit j ( j=1 , 2 , … , n The state of charge of ) energy storage units.

[0062] S203. Based on the photovoltaic output power difference of each phase photovoltaic-storage hybrid unit, the photovoltaic power operating point, the average state of charge, and the power compensation status of multiple energy storage units, control the operating modes of multiple photovoltaic units and multiple energy storage units.

[0063] In this embodiment, the photovoltaic output power difference of each phase photovoltaic-storage hybrid unit P Di The sum of the output power of the n photovoltaic units in each phase photovoltaic-storage hybrid unit. P PVi The average output power of all (3n) photovoltaic units in the photovoltaic-storage hybrid system P PVavg The difference is based on the difference in photovoltaic output power. P DiThe sum of the output power of the n photovoltaic units in each phase photovoltaic-storage hybrid unit can be determined. P PVi The output power of all (3n) photovoltaic units in the photovoltaic-storage hybrid system is greater than, less than, or equal to the average output power. P PVavg .

[0064] First, determine whether power compensation is enabled in the multiple energy storage units of each phase photovoltaic-energy storage hybrid unit. If power compensation is enabled in the multiple energy storage units of each phase photovoltaic-energy storage hybrid unit, then determine the difference in photovoltaic output power of each phase photovoltaic-energy storage hybrid unit. P Di To determine whether the photovoltaic units of each phase photovoltaic-storage hybrid unit need power compensation.

[0065] When determining whether power compensation is required for the photovoltaic units in each phase of the photovoltaic-storage hybrid unit, the photovoltaic power operating point of each phase of the photovoltaic-storage hybrid unit should be considered. X PVi The magnitude of the value determines whether the multiple photovoltaic units in each phase of the photovoltaic-storage hybrid unit can continue to operate in maximum power point tracking mode, ensuring grid voltage safety. Furthermore, it is based on the average state of charge of the k energy storage units in each phase of the photovoltaic-storage hybrid unit. SOC iavg The operating mode of each phase photovoltaic-storage hybrid unit's k energy storage units is determined as charging mode, discharging mode, or shutdown mode.

[0066] In one possible implementation, Figure 4 A flowchart illustrating the power compensation control method provided in the embodiments of this application. Figure 3 ,like Figure 4 As shown, the process of S203 above, which controls the operating modes of multiple photovoltaic units and multiple energy storage units based on the photovoltaic output power difference of each phase photovoltaic-energy storage hybrid unit, the photovoltaic power operating point, the average state of charge, and the power compensation status of multiple energy storage units, may include: S301. When the power compensation state of multiple energy storage units is enabled, if the difference in photovoltaic output power is not zero, the working mode of the multiple energy storage units is determined to be charging mode, discharging mode or shutdown mode based on the average state of charge.

[0067] In this embodiment, it is first determined whether the power compensation of the multiple energy storage units in each phase photovoltaic-storage hybrid unit is enabled. Only when power compensation is enabled can the power compensation of the photovoltaic unit be performed through the energy storage unit.

[0068] When power compensation is enabled in multiple energy storage units within each phase of a photovoltaic-energy storage hybrid unit, it is determined whether the difference in photovoltaic output power among the units is zero. If the difference is not zero, it means that the output power of the photovoltaic units in each phase is either too high or too low. If the difference is greater than zero, the output power of the photovoltaic units in each phase is determined to be too high; if the difference is less than zero, the output power of the photovoltaic units in each phase is determined to be too low. In this case, power compensation is required through the energy storage units.

[0069] Among them, in the difference of photovoltaic output power P Di When the value is greater than 0, the average state of charge of the k energy storage units in each phase of the photovoltaic-storage hybrid unit is used. SOC iavg This determines whether the k energy storage units adopt charging mode or decommissioning mode; specifically, when EN=1, P Di >0, SOC iavg < SOC max At that time, it is determined that there is excess photovoltaic power in the n photovoltaic units of each phase photovoltaic-storage hybrid unit, and the average state of charge of the k energy storage units of each phase photovoltaic-storage hybrid unit has not reached the upper limit of the state of charge operation. SOC max The system controls k energy storage units to operate in charging mode in order to absorb excess photovoltaic energy from n photovoltaic units.

[0070] Example, Figure 5 The equivalent circuit diagram of the energy storage unit charging time-storage hybrid system provided in the embodiments of this application is as follows: Figure 5 As shown, taking phase a as an example, when the energy storage unit is working in charging mode, the photovoltaic unit provides power generation to the grid and provides energy to the energy storage unit.

[0071] When EN=1, P Di >0, SOC iavg ≥ SOC max At that time, it was determined that the n photovoltaic units of each phase photovoltaic-storage hybrid unit had excess photovoltaic power, but the average state of charge of the k energy storage units of each phase photovoltaic-storage hybrid unit reached the upper limit of the state of charge operation. SOC max At this point, the k energy storage units can no longer absorb excess photovoltaic energy. In order to prevent the energy storage units from outputting energy, the k energy storage units are controlled to work in the exit mode.

[0072] Example, Figure 6The equivalent circuit diagram of the energy storage unit exiting the time-storage hybrid system provided in the embodiments of this application is as follows: Figure 6 As shown, taking phase a as an example, when the energy storage unit is in the off-state mode, the photovoltaic unit alone provides power generation to the grid.

[0073] Difference in photovoltaic output power P Di When the value is less than 0, the average state of charge of the k energy storage units in each phase of the photovoltaic-storage hybrid unit is used. SOC iavg Determine whether the k energy storage units adopt discharge mode or exit mode; specifically, when EN=1, P Di <0, SOC iavg > SOC min At that time, the photovoltaic power deficit provided by the n photovoltaic units in each phase photovoltaic-storage hybrid unit is determined, and the average state of charge of the k energy storage units in each phase photovoltaic-storage hybrid unit has not reached the lower limit of the state of charge operation. SOC min The k energy storage units are controlled to operate in discharge mode to compensate for the power deficit of the n photovoltaic units.

[0074] Example, Figure 7 The equivalent circuit diagram of the energy storage hybrid system provided in the embodiments of this application during energy storage unit discharge is as follows: Figure 7 As shown, taking phase a as an example, when the energy storage unit is working in discharge mode, the photovoltaic unit and the energy storage unit jointly provide power generation to the grid.

[0075] When EN=1, P Di <0, SOC iavg ≤ SOC min At that time, the photovoltaic power deficit provided by the n photovoltaic units in each phase photovoltaic-storage hybrid unit is determined, but the average state of charge of the k energy storage units in each phase photovoltaic-storage hybrid unit reaches the lower limit of the state of charge operation. SOC min At this point, the k energy storage units are unable to provide the photovoltaic power deficit to the photovoltaic unit. In order to prevent the energy storage units from absorbing energy, the k energy storage units are controlled to work in the exit mode.

[0076] S302. Based on the relationship between the photovoltaic power operating point and the maximum photovoltaic power operating point of each phase photovoltaic-storage hybrid unit, determine whether multiple photovoltaic units should exit the maximum power point tracking mode.

[0077] In this embodiment, the photovoltaic output power difference in each phase of the photovoltaic-storage hybrid unit P DiIf the power output of a photovoltaic (PV) system is not equal to zero, and if k energy storage units are in the off-state mode, meaning that energy compensation or absorption cannot be achieved through k energy storage units, it is necessary to prevent the PV power operating point of multiple PV units operating in maximum power point tracking mode from exceeding the maximum PV power operating point of each phase PV-storage hybrid unit, in order to ensure the power supply safety of the PV-storage hybrid system.

[0078] Therefore, it is necessary to determine the photovoltaic power operating point of each phase photovoltaic-storage hybrid unit. X PVi Is it greater than the maximum operating point of photovoltaic power per phase of the photovoltaic-storage hybrid unit? X PVimax Among them, the photovoltaic power operating point of any one phase photovoltaic-storage hybrid unit. X PVi Greater than the maximum operating point of the corresponding photovoltaic power of the photovoltaic-storage hybrid unit X PVimax To ensure system safety, it is necessary to control all photovoltaic units to exit maximum power point tracking mode and control the n photovoltaic units of each phase photovoltaic-storage hybrid unit to operate in constant power output mode, that is, to control the photovoltaic power operating point of each phase photovoltaic-storage hybrid unit. X PVi Equal to the maximum operating point of photovoltaic power per phase of the photovoltaic-storage hybrid unit X PVimax By controlling the conduction time of the full-bridge circuit of the photovoltaic unit, the output power is reduced until... X PVi = X PVimax For example, with EN=1, P Di >0, SOC iavg ≥ SOC max , X PVi > X PVimax When EN=1, P Di <0, SOC iavg ≤ SOC min , X PVi > X PVimax season X PVi = X PVimax Control all photovoltaic units to exit maximum power point tracking mode.

[0079] At the photovoltaic power operating point of the multiphase photovoltaic-storage hybrid unit XPVi Less than or equal to the maximum operating point of the corresponding photovoltaic power of the photovoltaic-storage hybrid unit X PVimax At this time, it is determined that all photovoltaic units in the multiphase photovoltaic-storage hybrid unit continue to operate in maximum power point tracking mode to ensure maximum power output of the photovoltaic units. For example, with EN=1, P Di >0, SOC iavg ≥ SOC max , X PVi ≤ X PVimax When EN=1, P Di <0, SOC iavg ≤ SOC min , X PVi ≤ X PVimax At that time, it was determined that all photovoltaic units of the multiphase photovoltaic-storage hybrid unit would continue to operate in maximum power point tracking mode.

[0080] In some embodiments, based on the sum of the maximum power generation of the n photovoltaic units in each phase photovoltaic-storage hybrid unit. P PVimax The sum of the rated power of all 3n photovoltaic units in the photovoltaic-storage hybrid system P PVR Calculate the maximum operating point of photovoltaic power for each phase of the photovoltaic-storage hybrid unit. X PVimax [ X PVamax , X PVbmax , X PVcmax ].

[0081] For example, the maximum operating point of photovoltaic power per phase of the photovoltaic-storage hybrid unit. X PVimax The calculation formula can be expressed as:

[0082] In some embodiments, the method may further include: If the power compensation status of multiple energy storage units is enabled and the difference in photovoltaic output power is zero, then the operating mode of multiple energy storage units is determined to be the shutdown mode.

[0083] In this embodiment, when the power compensation state of multiple energy storage units is enabled, if the photovoltaic output power difference of each phase photovoltaic-energy storage hybrid unit is zero, i.e., EN=1, P Di =0, indicating that the energy provided to the grid by the n photovoltaic units in each phase of the photovoltaic-storage hybrid unit does not require compensation. Multiple energy storage units in each phase of the hybrid unit can be controlled to operate in an off-state mode, meaning the bypass switches of multiple energy storage units can be closed, or the output power of multiple energy storage units can be controlled to be equal to 0. P Bij =0, where, P Bij Indicates the first i ( i=a , b , c The first phase of the photovoltaic-storage hybrid unit j ( j=1 , 2 , … , n The operating power of each energy storage unit is represented here as the output power.

[0084] In one possible implementation, when power compensation is enabled, the method may further include: If multiple energy storage units operate in charging mode, the input power of each energy storage unit is calculated using the first calculation method based on the difference in photovoltaic output power and the state of charge of each energy storage unit. If multiple energy storage units operate in discharging mode, the output power of each energy storage unit is calculated using the second calculation method based on the difference in photovoltaic output power and the state of charge of each energy storage unit.

[0085] In this embodiment, when EN=1, P Di >0, SOC iavg < SOC max At that time, multiple energy storage units in each phase of the photovoltaic-storage hybrid unit operate in charging mode, and the operating power of each energy storage unit is [not specified]. P Bij The formula for calculating input power here can be expressed as:

[0086] When EN=1, P Di <0, SOC iavg > SOC min At that time, multiple energy storage units in each phase of the photovoltaic-energy storage hybrid unit operate in discharge mode, and the operating power of each energy storage unit is... PBij The formula for calculating output power here can be expressed as:

[0087] In one possible implementation, the process of S203, which controls the operating modes of multiple photovoltaic units and multiple energy storage units based on the photovoltaic output power difference of each phase photovoltaic-energy storage hybrid unit, the photovoltaic power operating point, the average state of charge, and the power compensation state of multiple energy storage units, may further include: When the power compensation status of multiple energy storage units is off, the working mode of multiple energy storage units is determined to be charging mode, discharging mode or exit mode based on the relationship between the average state of charge and the preset state of charge, the photovoltaic power operating point and the maximum photovoltaic power operating point of each phase photovoltaic-storage hybrid unit, and whether multiple photovoltaic units exit the maximum power point tracking mode.

[0088] In this embodiment, when power compensation is turned off in multiple energy storage units of each phase photovoltaic-storage hybrid unit, power compensation for the photovoltaic unit is not performed using the energy storage units. However, to ensure that the energy stored in the energy storage units can support power compensation for the photovoltaic unit when power compensation is turned on, the state of charge (SOC) of the energy storage units needs to be controlled during the power compensation shutdown period to ensure that the SOC of the energy storage units meets the preset SOC value. SOC set For example, an upper limit can be set for the state of charge operation. SOC max 50%.

[0089] Specifically, the average state of charge of each phase of the photovoltaic-storage hybrid unit... SOC iavg Equal to the preset value of state of charge SOC set In this case, the energy storage unit of each phase photovoltaic-energy storage hybrid unit does not need to be charged or discharged. The energy storage unit of each phase photovoltaic-energy storage hybrid unit is controlled to operate in the off mode. In this case, the photovoltaic power operating point is determined. X PVi Maximum operating point of photovoltaic power per phase of photovoltaic-storage hybrid unit X PVimax The size relationship. If X PVi ≤ X PVimax It was determined that there were no safety issues with the photovoltaic-storage hybrid system, and the photovoltaic units in each phase of the hybrid system could continue to operate in maximum power point tracking mode. If any phase of the photovoltaic-storage hybrid system... X PVi > X PVimaxTo avoid safety issues in the photovoltaic-storage hybrid system, all photovoltaic units in the multiphase photovoltaic-storage hybrid unit are controlled to exit the maximum power point tracking mode.

[0090] Average state of charge of each phase of the photovoltaic-storage hybrid unit SOC iavg > SOC set In this scenario, the energy storage unit of each phase of the photovoltaic-energy storage hybrid unit needs to be discharged to ensure it operates in discharge mode. To avoid safety issues with the hybrid system, it's necessary to control all photovoltaic units in the multi-phase photovoltaic-energy storage hybrid unit to exit maximum power point tracking (MPPT) mode. Simultaneously, the hybrid power point of each phase of the photovoltaic-energy storage hybrid unit needs to be set... X PVBi [ X PVBa , X PVBb , X PVBc The maximum operating point of the hybrid power per phase of the photovoltaic-storage hybrid unit is less than or equal to that of the unit. X PVBimax [ X PVBamax X PVBbmax , X PVBcmax ].

[0091] Among them, the maximum operating point of hybrid power of each phase photovoltaic-storage hybrid unit X PVBimax The calculation formula can be expressed as:

[0092] in, P Bimax Indicates the first i ( i=a , b , c The sum of the maximum output power of the k energy storage units in the phase-photovoltaic-storage hybrid unit. P BR This represents the sum of the rated power of all energy storage units in the photovoltaic-storage hybrid system. Based on the above, the maximum operating point of the charging hybrid power when the energy storage units are operating in the charging state can be calculated. X PVBCimax [ X PVBCamax X PVBCbmax , X PVBCcmax [and the maximum operating point of the mixed discharge power when the energy storage unit is in discharge mode], and the maximum operating point of the mixed discharge power. X PVBDimax [ XPVBDamax X PVBDbmax , X PVBDcmax ].

[0093] Hybrid power operating point of each phase photovoltaic-storage hybrid unit X PVBi The calculation formula can be expressed as:

[0094] in, P Bi Indicates the first i ( i=a , b , c The sum of the output power of k energy storage units in a phase-photovoltaic-storage hybrid unit.

[0095] Average state of charge of each phase of the photovoltaic-storage hybrid unit SOC iavg > SOC set In this case, all photovoltaic units of the multiphase photovoltaic-storage hybrid unit are controlled to exit maximum power point tracking mode. Simultaneously, the hybrid power operating point of each phase photovoltaic-storage hybrid unit is set to... X PVBi ≤ X PVBDimax .

[0096] Average state of charge of each phase of the photovoltaic-storage hybrid unit SOC iavg < SOC set In this scenario, the energy storage unit of each phase of the photovoltaic-storage hybrid unit needs to be charged. The energy storage unit is then in charging mode to ensure all photovoltaic units in the multi-phase photovoltaic-storage hybrid unit continue operating in maximum power point tracking mode. Simultaneously, the hybrid power point of each phase of the photovoltaic-storage hybrid unit is set to... X PVBi ≤ X PVBCimax This ensures that the power generation of the photovoltaic unit can simultaneously meet the grid demand and the energy storage demand of the energy storage unit, without causing safety issues.

[0097] In one possible implementation, when the power compensation is off, the method may further include: If multiple energy storage units operate in charging mode, the input power of each energy storage unit is calculated using a third calculation method based on the maximum operating point of the hybrid power of each phase photovoltaic-energy storage unit, the sum of the rated power of all photovoltaic units, the sum of the rated power of all energy storage units, the sum of the output power of multiple photovoltaic units, and the state of charge of each energy storage unit. If multiple energy storage units operate in discharging mode, the output power of each energy storage unit is calculated using a fourth calculation method based on the maximum operating point of the hybrid power of each phase photovoltaic-energy storage unit, the sum of the rated power of all photovoltaic units, the sum of the rated power of all energy storage units, the sum of the output power of multiple photovoltaic units, and the state of charge of each energy storage unit.

[0098] In this embodiment, when EN=0, SOC iavg < SOC set At that time, multiple energy storage units in each phase of the photovoltaic-storage hybrid unit operate in charging mode, and the operating power of each energy storage unit is [not specified]. P Bij The formula for calculating input power here can be expressed as:

[0099] In this case, the maximum operating point of hybrid power is the maximum operating point of hybrid charging power.

[0100] When EN=0, SOC iavg > SOC set At that time, multiple energy storage units in each phase of the photovoltaic-energy storage hybrid unit operate in discharge mode, and the operating power of each energy storage unit is... P Bij The formula for calculating output power here can be expressed as:

[0101] In this case, the maximum operating point of mixed power is the maximum operating point of mixed power discharge.

[0102] The power compensation control method for the photovoltaic-storage hybrid system provided in the above embodiments adds energy storage units to the photovoltaic power generation system. Based on the output power of multiple photovoltaic units, the state of charge (SOC) of multiple energy storage units, and their power compensation states, it controls the operating modes of both the photovoltaic units and the energy storage units. The energy storage units compensate for the power generation of the photovoltaic units, ensuring consistent power generation across the multi-phase photovoltaic-storage hybrid system. This scheme reduces the complexity of inter-phase power balance control, expands the operating boundaries of the photovoltaic-storage hybrid system, and achieves high-quality grid-connected current output, maximum power generation efficiency of the photovoltaic units, and autonomous and safe operation of the energy storage units' SOC.

[0103] Example, Figure 8 A flowchart of the power compensation control method provided in the embodiments of this application is shown below. Figure 8 As shown, the power compensation control method for a photovoltaic-storage hybrid system includes the following steps: S401. Obtain the output power parameters of the photovoltaic unit and the state of charge parameters of the energy storage unit. The output power parameters include: the sum of the output powers. P PVi Average output power P PVavg Difference in photovoltaic output power P Di Sum of rated power P PVR Photovoltaic power operating point X PVi Maximum operating point of photovoltaic power X PVimax Hybrid power operating point X PVBi Maximum operating point of mixed power X PVBimax The charge state parameters include: the average charge state value. SOC iavg Upper limit of state of charge operation SOC max Lower limit of state of charge operation SOC min Preset value of state of charge SOC set .

[0104] S402. Determine if the power compensation status EN is equal to 1. If yes, jump to S403; if no, jump to S409.

[0105] S403, Determine the difference in photovoltaic output power P Di Is it equal to 0? If yes, determine that the photovoltaic-storage hybrid system is working in mode A, control all photovoltaic units to work in maximum power point tracking mode, and all energy storage units to work in exit mode. If no, jump to S404.

[0106] S404, Determine the difference in photovoltaic output power P Di Is it greater than 0? If yes, jump to S405; if no, jump to S407.

[0107] S405, Determine the average state of charge SOC iavg Is it less than the upper limit of the state of charge operation? SOC maxIf yes, determine that the photovoltaic-storage hybrid system is operating in mode B, control all photovoltaic units to operate in maximum power point tracking mode, and control the k energy storage units of this phase to operate in charging mode. If no, jump to S406.

[0108] S406. Determining the photovoltaic power operating point X PVi Is it less than or equal to the maximum operating point of photovoltaic power? X PVimax If yes, determine that the photovoltaic-storage hybrid system is operating in mode C, control all photovoltaic units to operate in maximum power point tracking mode, and control the k energy storage units in that phase to operate in exit mode. If no, determine that the photovoltaic-storage hybrid system is operating in mode D, and let... X PVi = X PVimax Control all photovoltaic units to exit the maximum power point tracking mode, and control the k energy storage units in this phase to work in the exit mode.

[0109] S407, Determine the average state of charge SOC iavg Is it greater than the lower limit of the state of charge? SOC min If yes, determine that the photovoltaic-storage hybrid system is operating in mode E, control all photovoltaic units to operate in maximum power point tracking mode, and control the k energy storage units of this phase to operate in discharge mode. If no, jump to S408.

[0110] S408, Determining the photovoltaic power operating point X PVi Is it less than or equal to the maximum operating point of photovoltaic power? X PVimax If yes, determine that the photovoltaic-storage hybrid system is operating in mode F, control all photovoltaic units to operate in maximum power point tracking mode, and control the k energy storage units of that phase to operate in exit mode. If no, determine that the photovoltaic-storage hybrid system is operating in mode G, and let... X PVi = X PVimax Control all photovoltaic units to exit the maximum power point tracking mode, and control the k energy storage units in this phase to work in the exit mode.

[0111] S409. Determine the average state of charge. SOC iavg Is it equal to the preset state of charge value? SOC set If yes, proceed to S410; if no, proceed to S411.

[0112] S410, Determine the photovoltaic power operating point X PViIs it less than or equal to the maximum operating point of photovoltaic power? X PVimax If yes, determine that the photovoltaic-storage hybrid system is operating in mode H, control all photovoltaic units to operate in maximum power point tracking mode, and control the k energy storage units of that phase to operate in exit mode. If no, let... X PVi = X PVimax The photovoltaic-storage hybrid system is determined to operate in mode I, and all photovoltaic units are controlled to exit the maximum power point tracking mode, while the k energy storage units in this phase are controlled to operate in the exit mode.

[0113] S411. Determine the average state of charge. SOC iavg Is it greater than the preset value for state of charge? SOC set If so, determine that the photovoltaic-storage hybrid system is operating in mode J, and let... X PVBi ≤ X PVBimax Control all photovoltaic units to exit maximum power point tracking mode, and control the k energy storage units in that phase to operate in discharge mode; if not, determine that the photovoltaic-energy storage hybrid system is operating in mode K, and set... X PVBi ≤ X PVBimax It controls all photovoltaic units to operate in maximum power point tracking mode and controls the k energy storage units in this phase to operate in charging mode.

[0114] Based on the above method embodiments, this application also provides a power compensation control device for a photovoltaic-storage hybrid system. The photovoltaic-storage hybrid system includes a multi-phase photovoltaic-storage hybrid unit. Each phase photovoltaic-storage hybrid unit includes multiple photovoltaic units and multiple energy storage units, and the multiple photovoltaic units and the multiple energy storage units are connected in series to the power grid. Figure 9 This is a schematic diagram of the power compensation control device provided in the embodiments of this application, as shown below. Figure 9 As shown, the device may include: Control module 501 is used to control all photovoltaic units of the multiphase photovoltaic-storage hybrid unit to operate in maximum power point tracking mode; The parameter acquisition module 502 is used to acquire the output power of multiple photovoltaic units in each phase photovoltaic-storage hybrid unit and the state of charge and power compensation status of multiple energy storage units in each phase photovoltaic-storage hybrid unit. The control module 501 is also used to control the operating modes of multiple photovoltaic units and multiple energy storage units according to the output power of multiple photovoltaic units, the state of charge and power compensation status of multiple energy storage units, so as to make the power generation of the multiphase photovoltaic-energy storage hybrid unit equal.

[0115] Optionally, the control module 501 is specifically used to calculate the photovoltaic output power difference and photovoltaic power operating point of each phase photovoltaic-storage hybrid unit based on the output power of multiple photovoltaic units and the output power of all photovoltaic units; to calculate the average state of charge of each phase photovoltaic-storage hybrid unit based on the state of charge of multiple energy storage units; and to control the operating modes of multiple photovoltaic units and multiple energy storage units based on the photovoltaic output power difference, photovoltaic power operating point, average state of charge, and power compensation status of each phase photovoltaic-storage hybrid unit.

[0116] Optionally, the control module 501 is specifically used to determine, when the power compensation state of multiple energy storage units is enabled, if the difference in photovoltaic output power is not zero, the operating mode of the multiple energy storage units is charging mode, discharging mode or exit mode based on the average state of charge; and to determine whether the multiple photovoltaic units exit the maximum power point tracking mode based on the relationship between the photovoltaic power operating point and the maximum photovoltaic power operating point of each phase photovoltaic-storage hybrid unit.

[0117] Optionally, the control module 501 is also used to determine the working mode of the multiple energy storage units as the exit mode when the power compensation state of the multiple energy storage units is enabled and the difference in photovoltaic output power is zero.

[0118] Optionally, the control module 501 is further configured to, if the multiple energy storage units are operating in charging mode, calculate the input power of each energy storage unit using a first calculation method based on the difference in photovoltaic output power and the state of charge of each energy storage unit; and if the multiple energy storage units are operating in discharging mode, calculate the output power of each energy storage unit using a second calculation method based on the difference in photovoltaic output power and the state of charge of each energy storage unit.

[0119] Optionally, the control module 501 is further configured to determine the operating mode of the multiple energy storage units as charging mode, discharging mode, or exit mode, based on the relationship between the average state of charge and the preset state of charge, the relationship between the photovoltaic power operating point and the maximum photovoltaic power operating point of each phase photovoltaic-storage hybrid unit, when the power compensation state of the multiple energy storage units is off, and to determine whether the multiple photovoltaic units exit the maximum power point tracking mode.

[0120] Optionally, the control module 501 is further configured to, if the multiple energy storage units are operating in charging mode, calculate the input power of each energy storage unit using a third calculation method based on the maximum operating point of the hybrid power of each phase photovoltaic-energy storage hybrid unit, the sum of the rated power of all photovoltaic units, the sum of the rated power of all energy storage units, the sum of the output power of multiple photovoltaic units, and the state of charge of each energy storage unit; and if the multiple energy storage units are operating in discharging mode, calculate the output power of each energy storage unit using a fourth calculation method based on the maximum operating point of the hybrid power of each phase photovoltaic-energy storage hybrid unit, the sum of the rated power of all photovoltaic units, the sum of the rated power of all energy storage units, the sum of the output power of multiple photovoltaic units, and the state of charge of each energy storage unit.

[0121] The above-described device is used to execute the method provided in the foregoing embodiments, and its implementation principle and technical effect are similar, so they will not be described again here.

[0122] These modules can be one or more integrated circuits configured to implement the above methods, such as one or more Application Specific Integrated Circuits (ASICs), one or more microprocessors, or one or more Field Programmable Gate Arrays (FPGAs). Alternatively, when a module is implemented using processing element scheduler code, the processing element can be a general-purpose processor, such as a Central Processing Unit (CPU) or other processor capable of calling program code. Furthermore, these modules can be integrated together as a system-on-a-chip (SOC).

[0123] In one possible implementation, this application embodiment also provides a controller, which is connected to the control terminals of all photovoltaic units and all energy storage units in the photovoltaic-storage hybrid system. The controller executes the steps of the power compensation control method described above to perform power compensation on the multiphase photovoltaic-storage hybrid units of the photovoltaic-storage hybrid system.

[0124] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A power compensation control method for a photovoltaic-storage hybrid system, characterized in that, The photovoltaic-storage hybrid system includes a multi-phase photovoltaic-storage hybrid unit, each phase photovoltaic-storage hybrid unit including: multiple photovoltaic units and multiple energy storage units, the multiple photovoltaic units and the multiple energy storage units being connected in series to the power grid, and the method including: Control all photovoltaic units of the multiphase photovoltaic-storage hybrid unit to operate in maximum power point tracking mode; The output power of multiple photovoltaic units in each phase photovoltaic-storage hybrid unit and the state of charge and power compensation status of multiple energy storage units in each phase photovoltaic-storage hybrid unit are obtained. Based on the output power of the multiple photovoltaic units, the state of charge and power compensation state of the multiple energy storage units, the operating modes of the multiple photovoltaic units and the multiple energy storage units are controlled to ensure that the power generation of the multiphase photovoltaic-energy storage hybrid unit is equal.

2. The method as described in claim 1, characterized in that, The step of controlling the operating modes of the multiple photovoltaic units and the multiple energy storage units based on the output power of the multiple photovoltaic units, the state of charge of the multiple energy storage units, and the power compensation state includes: Based on the output power of the plurality of photovoltaic units and the output power of all photovoltaic units, calculate the photovoltaic output power difference and photovoltaic power operating point of each phase photovoltaic-storage hybrid unit; Calculate the average state of charge of each phase photovoltaic-storage hybrid unit based on the state of charge of the plurality of energy storage units; Based on the photovoltaic output power difference, photovoltaic power operating point, average state of charge, and power compensation status of each photovoltaic-storage hybrid unit, the operating modes of the multiple photovoltaic units and the multiple energy storage units are controlled.

3. The method as described in claim 2, characterized in that, The method of controlling the operating modes of the multiple photovoltaic units and the multiple energy storage units based on the photovoltaic output power difference of each phase photovoltaic-energy storage hybrid unit, the photovoltaic power operating point, the average state of charge, and the power compensation status of the multiple energy storage units includes: When the power compensation state of the plurality of energy storage units is enabled, if the difference in photovoltaic output power is not zero, the operating mode of the plurality of energy storage units is determined to be charging mode, discharging mode or deactivation mode based on the average state of charge. Based on the relationship between the photovoltaic power operating point and the maximum photovoltaic power operating point of each phase photovoltaic-storage hybrid unit, it is determined whether the multiple photovoltaic units should exit the maximum power point tracking mode.

4. The method as described in claim 3, characterized in that, The method further includes: If the power compensation status of the plurality of energy storage units is enabled and the difference in photovoltaic output power is zero, then the operating mode of the plurality of energy storage units is determined to be the shutdown mode.

5. The method as described in claim 3, characterized in that, The method further includes: If the multiple energy storage units are operating in charging mode, the input power of each energy storage unit is calculated using the first calculation method based on the photovoltaic output power difference and the state of charge of each energy storage unit. If the multiple energy storage units operate in discharge mode, the output power of each energy storage unit is calculated using a second calculation method based on the photovoltaic output power difference and the state of charge of each energy storage unit.

6. The method as described in claim 2, characterized in that, The method of controlling the operating modes of the multiple photovoltaic units and the multiple energy storage units based on the photovoltaic output power difference, photovoltaic power operating point, average state of charge, and power compensation status of each phase photovoltaic-energy storage hybrid unit includes: When the power compensation status of the plurality of energy storage units is off, the working mode of the plurality of energy storage units is determined to be charging mode, discharging mode or exit mode based on the relationship between the average state of charge and the preset state of charge, the relationship between the photovoltaic power operating point and the maximum photovoltaic power operating point of each phase photovoltaic-storage hybrid unit, and whether the plurality of photovoltaic units exit the maximum power point tracking mode.

7. The method according to claim 6, characterized in that, The method further includes: If the working mode of the plurality of energy storage units is charging mode, the input power of each energy storage unit is calculated using a third calculation method based on the maximum operating point of the hybrid power of each phase photovoltaic-energy storage hybrid unit, the sum of the rated power of all photovoltaic units, the sum of the rated power of all energy storage units, the sum of the output power of the plurality of photovoltaic units, and the state of charge of each energy storage unit. If the multiple energy storage units operate in discharge mode, the output power of each energy storage unit is calculated using a fourth calculation method based on the maximum operating point of the hybrid power of each phase photovoltaic-energy storage unit, the sum of the rated power of all photovoltaic units, the sum of the rated power of all energy storage units, the sum of the output power of the multiple photovoltaic units, and the state of charge of each energy storage unit.

8. A power compensation control device for a photovoltaic-storage hybrid system, characterized in that, The photovoltaic-storage hybrid system includes a multi-phase photovoltaic-storage hybrid unit, each phase photovoltaic-storage hybrid unit including: multiple photovoltaic units and multiple energy storage units, the multiple photovoltaic units and the multiple energy storage units being connected in series to the power grid, and the device including: The control module is used to control all photovoltaic units of the multiphase photovoltaic-storage hybrid unit to operate in maximum power point tracking mode; The parameter acquisition module is used to acquire the output power of multiple photovoltaic units in each phase photovoltaic-storage hybrid unit and the state of charge and power compensation status of multiple energy storage units in each phase photovoltaic-storage hybrid unit. The control module is further configured to control the operating modes of the multiple photovoltaic units and the multiple energy storage units based on the output power of the multiple photovoltaic units, the state of charge of the multiple energy storage units, and the power compensation state, so as to make the power generation of the multiphase photovoltaic-energy storage hybrid unit equal.

9. A controller, characterized in that, The controller is connected to the control terminals of all photovoltaic units and all energy storage units in the photovoltaic-storage hybrid system. The controller executes the steps of the power compensation control method as described in any one of claims 1 to 7 to perform power compensation on the multiphase photovoltaic-storage hybrid units of the photovoltaic-storage hybrid system.

10. A photovoltaic-storage hybrid system, characterized in that, The photovoltaic-storage hybrid system includes a multi-phase photovoltaic-storage hybrid unit. Each phase photovoltaic-storage hybrid unit includes multiple photovoltaic units and multiple energy storage units. The DC side of each photovoltaic unit is connected to a photovoltaic module, and the DC side of each energy storage unit is connected to a battery module. The AC side of each photovoltaic unit and the AC side of each photovoltaic unit are connected in parallel with a bypass switch. The multiple photovoltaic units and the AC side of the multiple energy storage units are connected in series to the power grid. The photovoltaic-storage hybrid system uses the power compensation control method as described in any one of claims 1 to 7 for power compensation.

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