Photovoltaic energy storage system and energy storage control method and control apparatus therefor

Abstract

Disclosed in the present invention are a photovoltaic energy storage system and an energy storage control method and control apparatus therefor. The control method comprises: acquiring a real-time photovoltaic output power, a real-time load power and the real-time remaining electric quantity; on the basis of the real-time photovoltaic output power and the real-time load power, obtaining the real-time power difference; and when a first condition is met, executing a first charging mode, wherein the first charging mode comprises: on the basis of the real-time power difference, an energy storage assembly power threshold value and a power loop regulator, obtaining a first given current value; on the basis of the first given current value and a real-time energy storage assembly current threshold value, determining a second given current value; on the basis of a real-time capacitor voltage in a first DC-DC conversion circuit and a first voltage loop regulator, obtaining a third given current value; on the basis of the second given current value and the third given current value, determining a given current value, and obtaining a first duty cycle by means of a first current loop regulator; and on the basis of the first duty cycle, generating a first PWM signal to control a switch transistor. By means of the present invention, the energy utilization rate and system performance of a photovoltaic energy storage system can be improved.

Description

Photovoltaic energy storage system and its energy storage control method and control device Technical Field

[0001] This invention belongs to the field of photovoltaic energy storage technology, specifically, it relates to a photovoltaic energy storage system and its energy storage control method and control device. Background Technology

[0002] As an application system for on-site energy collection and consumption, photovoltaic energy storage systems have been widely used in various fields such as production and daily life due to the increasingly urgent need for energy conservation and emission reduction and the continuous maturation of photovoltaic technology.

[0003] The output power of photovoltaic (PV) modules in a solar-storage system fluctuates significantly due to variations in sunlight levels, affecting the operational stability of the load. Typically, when solar energy is abundant, PV modules convert solar energy into electricity, partly to meet the load's power needs, and storing excess energy in energy storage components such as batteries. When solar energy is insufficient, energy storage components can be used to power the load. This maximizes the utilization of renewable green energy, reduces grid power consumption, and achieves energy conservation and emission reduction goals.

[0004] For photovoltaic-storage systems, the energy storage control of energy storage components is crucial to the energy utilization rate and operational performance of the entire system. How to improve the energy utilization rate and system performance of photovoltaic-storage systems through energy storage control is an urgent problem to be solved. Technical issues

[0005] One objective of this invention is to provide an energy storage control method for a photovoltaic energy storage system, so as to improve the energy utilization rate and system performance of the photovoltaic energy storage system. Technical solutions

[0006] To achieve the above-mentioned objectives, the energy storage control method for a photovoltaic energy storage system provided by this invention adopts the following technical solution:

[0007] A method for controlling energy storage in a photovoltaic-energy storage system, the system comprising a photovoltaic module and an energy storage module, wherein the energy storage module is connected to a DC bus via a first DC-DC converter circuit, and the photovoltaic module is connected to the DC bus via a second DC-DC converter circuit; the control method includes:

[0008] The real-time photovoltaic output power of the photovoltaic module, the real-time load power of the load connected to the DC bus, and the real-time remaining power of the energy storage module are obtained.

[0009] The difference between the real-time photovoltaic output power and the real-time load power is obtained as the real-time power difference;

[0010] When the first condition is met, the first charging mode is executed;

[0011] The first condition includes: the real-time remaining power is less than a first power threshold, the real-time power difference is greater than 0, and the real-time load power is greater than 0;

[0012] The first charging mode includes:

[0013] The real-time power difference and the energy storage component power threshold are input into the power loop regulator to obtain the first current setpoint; the real-time energy storage component current threshold corresponding to the real-time remaining power is obtained, and the smaller value between the first current setpoint and the real-time energy storage component current threshold is determined as the second current setpoint;

[0014] Obtain the real-time capacitor voltage in the first DC-DC converter circuit, and input the real-time capacitor voltage and the first voltage setpoint value into the first voltage loop regulator to obtain the third current setpoint value;

[0015] The smaller of the second current setpoint and the third current setpoint is determined as the current setpoint of the first current loop regulator. The current setpoint of the first current loop regulator and the real-time feedback current in the first DC-DC converter circuit are input into the first current loop regulator to obtain the first duty cycle.

[0016] A first PWM signal is generated based on the first duty cycle, and the switching transistor in the first DC-DC converter circuit is controlled based on the first PWM signal.

[0017] Another objective of this invention is to provide an energy storage control device for a photovoltaic energy storage system, so as to improve the energy utilization rate and system performance of the photovoltaic energy storage system.

[0018] To achieve the above-mentioned objectives, the energy storage control device for the photovoltaic energy storage system provided by this invention adopts the following technical solution:

[0019] A photovoltaic-energy storage system energy storage control device is provided, wherein the photovoltaic-energy storage system includes photovoltaic modules and energy storage modules, the energy storage modules are connected to a DC bus via a first DC-DC converter circuit, and the photovoltaic modules are connected to the DC bus via a second DC-DC converter circuit; the control device includes:

[0020] The controller is connected to the first DC-DC converter circuit and the second DC-DC converter circuit respectively, and is configured to execute the above-described energy storage control method for the photovoltaic energy storage system.

[0021] Another object of the present invention is to provide a photovoltaic-storage system with high energy utilization and system performance. The photovoltaic-storage system includes photovoltaic modules and energy storage modules. The energy storage modules are connected to a DC bus via a first DC-DC converter circuit, and the photovoltaic modules are connected to the DC bus via a second DC-DC converter circuit. The photovoltaic-storage system also includes the aforementioned photovoltaic-storage system energy storage control device.

[0022] Another object of the present invention is to provide a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the above-described energy storage control method for a photovoltaic energy storage system is implemented. Beneficial effects

[0023] Compared with the prior art, the advantages and positive effects of the present invention are:

[0024] The photovoltaic-energy storage system and its energy storage control method and device provided by this invention use the real-time photovoltaic output power of the photovoltaic modules, the real-time load power of the loads in the system, and the real-time remaining energy of the energy storage modules in the system as parameters to determine whether to execute a first charging mode. When it is determined to execute the first charging mode, a first current setpoint is determined by power adjustment based on the real-time photovoltaic output power, the real-time load power, and the power threshold of the energy storage modules. A second current setpoint is obtained by limiting the first current setpoint based on the real-time remaining energy of the energy storage modules. The second current setpoint is then used to limit a third current setpoint determined by the voltage loop regulator to finally obtain a current setpoint. Current adjustment is performed based on this current setpoint and the real-time feedback current to obtain a first duty cycle. P is generated based on the first duty cycle. The WM signal controls the switching transistor to achieve charging control of the energy storage module. It not only uses the real-time photovoltaic output power of the photovoltaic module as a judgment parameter when determining whether to execute the first charging mode, but also determines the charging current based on the real-time photovoltaic output power. This integrates the real-time photovoltaic output power of the photovoltaic module throughout the entire energy storage control process, improving the energy utilization rate of the photovoltaic-energy storage system. Furthermore, it uses the real-time remaining capacity of the energy storage module as a judgment parameter when determining whether to execute the first charging mode, and also determines the charging current based on the real-time remaining capacity of the energy storage module. This also integrates the real-time capacity of the energy storage module throughout the entire energy storage control process. Combined with the control of real-time photovoltaic output power, this reduces the number of charging cycles and charging impacts of the energy storage module, improving the reliability and lifespan of the energy storage module, thereby enhancing the performance of the photovoltaic-energy storage system.

[0025] Other features and advantages of the present invention will become clearer after reading the detailed embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 is a structural block diagram of an embodiment of the photovoltaic energy storage system of the present invention;

[0028] Figure 2 is a control block diagram of the first embodiment of the energy storage control method for the photovoltaic energy storage system of the present invention;

[0029] Figure 3 is a control block diagram of the second embodiment of the energy storage control method for the photovoltaic energy storage system of the present invention;

[0030] Figure 4 is a control block diagram of the third embodiment of the energy storage control method for the photovoltaic energy storage system of the present invention;

[0031] Figure 5 is a control block diagram of the fourth embodiment of the energy storage control method for the photovoltaic energy storage system of the present invention;

[0032] Figure 6 is a schematic diagram of the charging relationship between the remaining power and the current threshold in one embodiment of the energy storage control method of the photovoltaic energy storage system of the present invention;

[0033] Figure 7 is a schematic diagram of the discharge relationship between the remaining power and the current threshold in one embodiment of the energy storage control method of the photovoltaic energy storage system of the present invention. Embodiments of the present invention

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] It should be noted that the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0036] Figure 1 shows a structural block diagram of an embodiment of the photovoltaic-energy storage system of the present invention. As shown in Figure 1, in this embodiment, the photovoltaic-energy storage system includes a photovoltaic module 11 and an energy storage module 12. The energy storage module 12 is connected to the DC bus via a first DC-DC converter circuit 13, and the photovoltaic module 11 is connected to the DC bus via a second DC-DC converter circuit 14. The load in the photovoltaic-energy storage system (not shown in the figure) is directly connected to the DC bus or connected to the DC bus via an inverter circuit. In some embodiments, the first DC-DC converter circuit 13 adopts a Boost-Buck circuit architecture, and the second DC-DC converter circuit 14 adopts a Boost circuit architecture.

[0037] The photovoltaic energy storage system also includes an energy storage control device, which includes a controller 15. The controller 15 is connected to the first DC-DC converter circuit 13 and the second DC-DC converter circuit 14, respectively, and is used to control the switching state of the switching transistors in the two circuits, thereby achieving at least the energy storage control of the photovoltaic energy storage system. Specific control methods and processes are described in subsequent embodiments.

[0038] Figure 2 shows a control block diagram of the first embodiment of the photovoltaic energy storage system energy storage control method of the present invention, specifically, a control block diagram for executing the first charging mode.

[0039] Referring to the structural block diagram in Figure 1, in the energy storage control method of this embodiment, it is first determined whether the first condition for executing the first charging mode is met.

[0040] Specifically, this involves obtaining the real-time photovoltaic output power P of the photovoltaic module. pv Real-time load power P of the load connected to the DC bus load And the real-time remaining power (SOC) of the energy storage components. The values ​​of each parameter are obtained using methods from relevant technologies, which will not be specifically limited or elaborated here.

[0041] Obtain real-time photovoltaic output power P pv With real-time load power P load The difference, as the real-time power difference P dev P dev =P pv -P load .

[0042] When the first condition is met, the first charging mode is executed.

[0043] The first condition includes: the real-time remaining power SOC is less than the first power threshold, and the real-time power difference P dev Greater than 0, and real-time load power P load Greater than 0.

[0044] The first energy threshold is a set value, which can be expressed as a percentage of the rated capacity of the energy storage component. In some embodiments, the first energy threshold is expressed as SOC (State of Charge). max It can be 80% of the rated capacity of the energy storage component, or other percentages of the rated capacity. The specific value can be set according to the actual situation, and this embodiment does not limit it.

[0045] If the real-time remaining power SOC is less than the first power threshold in the first condition, it indicates that the energy storage component has insufficient power and can be charged; if the real-time power difference P is satisfied in the first condition... dev A value greater than 0 indicates that the photovoltaic module has sufficient power output, which, in addition to meeting the load power demand, can also increase the additional output power; satisfying the first condition of real-time load power P load A value greater than 0 indicates that the photovoltaic energy storage system is operating under load.

[0046] After the first condition is met, the following first charging mode will be executed.

[0047] Obtain the power threshold P of the energy storage component bat For a photovoltaic energy storage system with a defined structure, the power threshold P bat This is a known value, typically the maximum available power of the energy storage component.

[0048] Real-time power difference P dev With the power threshold P of energy storage components bat Input the power loop regulator to obtain the first current setpoint I. set1 The power loop regulator can be any regulator in the related art, such as a PI regulator, a PID regulator, or a P regulator. This embodiment does not limit the specific implementation of the power loop regulator.

[0049] It also obtains the real-time energy storage component current threshold I corresponding to the real-time remaining power SOC. limt Then, the first current setpoint I is... set1 and real-time energy storage component current threshold I limt The input is sent to selector 1, and selector 1 will select the first current setpoint I. set1 and real-time energy storage component current threshold I limt The smaller value in is determined as the second current setpoint I. set2 And output. Real-time energy storage component current threshold I limt Corresponding to the real-time remaining energy capacity (SOC) of the energy storage module, when the real-time remaining energy capacity (SOC) is known, the corresponding real-time energy storage module current threshold I... limt It is also knowable.

[0050] It also obtains the real-time capacitor voltage V in the first DC-DC converter circuit. dc1The real-time capacitor voltage V dc1 and the first voltage setpoint V set1 Input the first voltage loop regulator to obtain the third current setpoint I. set3 Real-time capacitor voltage V dc1 The method used in related technologies will be employed, without specific limitations or detailed explanations here. The first voltage setpoint V... set1 The set value is determined based on the system structure and control requirements. The first voltage loop regulator can be a regulator in related technologies, such as a PI regulator, a PID regulator, or a P regulator. This embodiment does not limit the specific implementation of the first voltage loop regulator.

[0051] The second current setpoint I output by selector 1 set2 and the third current setpoint I output by the first voltage loop regulator set3 The input is sent to selector 2, which selects the smaller of the two values ​​as the current setpoint I for the first current loop regulator. * 1, and set the current value I. * The real-time feedback current I1 from the first DC-DC converter circuit is input to the first current loop regulator, which outputs a first duty cycle D1. The real-time feedback current I1 from the first DC-DC converter circuit is obtained using methods from related technologies, which are not specifically limited or described in detail here. The first current loop regulator can be a regulator from related technologies, such as a PI regulator, a PID regulator, or a P regulator. This embodiment does not limit the specific implementation of the first current loop regulator.

[0052] The first duty cycle D1 is input to the PWM output module. The PWM output module generates a first PWM signal based on the first duty cycle D1 and sends it to the first DC-DC converter circuit. The first PWM signal is used to control the switching state of the switching transistor in the first DC-DC converter circuit, thereby realizing the charging control of the energy storage component.

[0053] In this embodiment, the real-time photovoltaic output power of the photovoltaic module in the system, the real-time load power of the load in the system, and the real-time remaining power of the energy storage module in the system are used as parameters to determine whether to execute the first charging mode. When it is determined to execute the first charging mode, a first current setpoint is determined by power adjustment based on the real-time photovoltaic output power, the real-time load power, and the power threshold of the energy storage module. A second current setpoint is obtained by limiting the first current setpoint based on the real-time remaining power of the energy storage module. The third current setpoint determined by the first voltage loop regulator is then limited by the second current setpoint to finally obtain the current setpoint. The current is adjusted based on the current setpoint and the real-time feedback current to obtain a first duty cycle. A PWM signal is generated based on the first duty cycle to control the switching transistor, thereby realizing the charging control of the energy storage module. In the energy storage control process, not only is the real-time photovoltaic output power of the photovoltaic module used as a judgment parameter when determining whether to execute the first charging mode, but the charging current is also determined based on the real-time photovoltaic output power. This integrates the real-time photovoltaic output power of the photovoltaic module throughout the entire energy storage control process, improving the energy utilization rate of the photovoltaic-energy storage system. Similarly, when determining whether to execute the first charging mode, the real-time remaining capacity of the energy storage module is used as a judgment parameter, and the charging current is also determined based on the real-time remaining capacity of the energy storage module. This also integrates the real-time capacity of the energy storage module throughout the entire energy storage control process. Combined with the control of real-time photovoltaic output power, this reduces the number of charging cycles and charging impacts of the energy storage module, improves the reliability and lifespan of the energy storage module, and thus enhances the performance of the photovoltaic-energy storage system.

[0054] Figure 3 shows a control block diagram of the second embodiment of the photovoltaic energy storage system energy storage control method of the present invention, specifically, a control block diagram for executing the second charging mode.

[0055] Referring to the structural block diagram in Figure 1, in the energy storage control method of this embodiment, it is first determined whether the second condition for executing the second charging mode is met.

[0056] The second condition includes: the real-time remaining power SOC is less than the first power threshold, and the real-time power difference P dev Greater than 0, and real-time load power P load Equals 0. Real-time remaining battery SOC, first battery threshold, real-time power difference P dev and real-time load power P load For the meaning and acquisition method of , please refer to the description of the above embodiments.

[0057] If the real-time remaining power SOC is less than the first power threshold in the first condition, it indicates that the energy storage component has insufficient power and can be charged; if the real-time power difference P is satisfied in the first condition... devA value greater than 0 indicates that the photovoltaic module has sufficient power output, which, in addition to meeting the load power demand, can also increase the additional output power; satisfying the first condition of real-time load power P load A value of 0 indicates that the photovoltaic-storage system is only charging the energy storage components.

[0058] After the second condition mentioned above is met, the second charging mode will be executed as follows.

[0059] Obtain the real-time capacitor voltage V in the first DC-DC converter circuit dc1 The real-time capacitor voltage V dc1 and the first voltage setpoint V set1 Input the first voltage loop regulator to obtain the third current setpoint I. set3 .

[0060] Obtain the real-time energy storage component current threshold I corresponding to the real-time remaining power SOC. limt The real-time energy storage component current threshold I limt and the third current setpoint I output by the first voltage loop regulator set3 The input is sent to selector 3, which selects the smaller of the two values ​​as the current setpoint I for the first current loop regulator. * 1, and set the current value I. * 1. The real-time feedback current I1 obtained from the first DC-DC converter circuit is input to the first current loop regulator, and the first duty cycle D1 is output through the first current loop regulator.

[0061] The first duty cycle D1 is input to the PWM output module. The PWM output module generates a first PWM signal based on the first duty cycle D1 and sends it to the first DC-DC converter circuit. The first PWM signal is used to control the switching state of the switching transistor in the first DC-DC converter circuit, thereby realizing the charging control of the energy storage component.

[0062] For the meaning of each parameter, the method of obtaining it, and the structure of each regulator in this embodiment, please refer to the description of the above embodiment.

[0063] In the energy storage control process of this embodiment, when determining whether to execute the second charging mode, the real-time photovoltaic output power of the photovoltaic module and the real-time remaining power of the energy storage module are used as judgment parameters. The charging current is also determined based on the real-time remaining power of the energy storage module. This can improve the energy utilization rate of the photovoltaic-energy storage system, reduce the number of charging cycles and charging impacts of the energy storage module, improve the reliability and service life of the energy storage module, and thus improve the performance of the photovoltaic-energy storage system.

[0064] Figure 4 shows a control block diagram of a third embodiment of the energy storage control method for a photovoltaic energy storage system of the present invention, specifically, a control block diagram for executing the first discharge mode.

[0065] Referring to the structural block diagram in Figure 1, in the energy storage control method of this embodiment, it is first determined whether the third condition for executing the first discharge mode is met.

[0066] The third condition includes: the real-time remaining power SOC is greater than the second power threshold, and the real-time power difference P dev Less than 0, and the real-time photovoltaic output power P pv Greater than 0.

[0067] The second energy threshold is a set value, which can be expressed as a percentage of the rated capacity of the energy storage component, and the second energy threshold is less than the first energy threshold. In some embodiments, the second energy threshold is expressed as SOC (State of Charge). min It can be 20% of the rated capacity of the energy storage component, or other percentages of the rated capacity. The specific value can be set according to the actual situation, and this embodiment does not limit it.

[0068] If the real-time remaining charge (SOC) is greater than the second charge threshold in the third condition, it indicates that the energy storage component has a certain amount of charge and can discharge; if the real-time power difference (P) in the third condition is also met, it indicates that the energy storage component has sufficient charge and can discharge. dev A value less than 0 indicates that the output power provided by the photovoltaic module cannot meet the load demand; the real-time photovoltaic output power P in the third condition is met. pv A value greater than 0 indicates that the photovoltaic module is in a power supply state and can provide part of the power required by the load.

[0069] After the third condition mentioned above is met, the first discharge mode will be executed as follows, in which the photovoltaic modules and energy storage modules jointly provide the required power to the load.

[0070] First, the real-time power difference P dev The absolute value and the load power change threshold P limt Compare the load power change threshold P. limt This is a known value, typically used to reflect the allowable power variation during load operation.

[0071] Real-time power difference P dev The absolute value is less than or equal to the load power change threshold P. limt When the output power fluctuation of the photovoltaic module is within the allowable power variation range of the load, it indicates that the photovoltaic module alone can ensure the stable operation of the load within the allowable range. At this time, the energy storage module will be controlled to stop discharging in order to make full use of photovoltaic energy, improve the energy utilization rate of the photovoltaic-energy storage system, reduce the number of discharges and discharge impacts of the energy storage module, improve the reliability and service life of the energy storage module, and thus improve the performance of the photovoltaic-energy storage system.

[0072] Real-time power difference P dev The absolute value is greater than the load power change threshold Plimt At that time, the energy storage component is controlled to discharge. Specifically, the real-time capacitor voltage V in the second DC-DC converter circuit is obtained. dc2 The real-time capacitor voltage V dc2 Second voltage setpoint V set2 Input the second voltage loop regulator to obtain the fourth current setpoint I. set4 Real-time capacitor voltage V dc2 The method used in related technologies will be employed, without specific limitations or detailed explanations here. The second voltage setpoint V... set2 The set value is determined based on the system architecture and control requirements. The second voltage loop regulator can be a regulator from related technologies, such as a PI regulator, a PID regulator, or a P regulator. This embodiment does not limit the specific implementation of the second voltage loop regulator.

[0073] It also obtains the real-time energy storage component current threshold I corresponding to the real-time remaining power SOC. limt The real-time energy storage component current threshold I limt and the fourth current setpoint I output from the second voltage loop regulator. set4 The input is sent to selector 4, which selects the smaller of the two values ​​as the current setpoint I for the second current loop regulator. * 2, and set the current value I. * 2. The real-time feedback current I1 from the first DC-DC converter circuit is input to the second current loop regulator, and the second current loop regulator outputs the first duty cycle D1. The second current loop regulator can be a regulator in related technologies, such as a PI regulator, a PID regulator, or a P regulator. This embodiment does not limit the specific implementation of the second current loop regulator.

[0074] The first duty cycle D1 is input to the PWM output module. The PWM output module generates a first PWM signal based on the first duty cycle D1 and sends it to the first DC-DC converter circuit. The first PWM signal is used to control the switching state of the switching transistor in the first DC-DC converter circuit, thereby realizing the discharge control of the energy storage component.

[0075] In the energy storage control process of this embodiment, when determining whether to execute the first discharge mode, the real-time photovoltaic output power of the photovoltaic module and the real-time remaining power of the energy storage module are used as judgment parameters. The charging current is also determined based on the real-time remaining power of the energy storage module. This can improve the energy utilization rate of the photovoltaic-energy storage system, reduce the number of discharges and discharge impacts of the energy storage module, improve the reliability and service life of the energy storage module, and thus improve the performance of the photovoltaic-energy storage system.

[0076] In some other embodiments, the energy storage control method for the photovoltaic-energy storage system further includes a process of executing a second discharge mode. In these embodiments, it is first determined whether a fourth condition for executing the second discharge mode is met.

[0077] The fourth condition includes: the real-time remaining power SOC is greater than the second power threshold, and the real-time power difference P dev Less than 0, and the real-time photovoltaic output power P pv It equals 0.

[0078] If the real-time remaining charge (SOC) is greater than the second charge threshold in the third condition, it indicates that the energy storage component has a certain amount of charge and can discharge; if the real-time power difference (P) in the third condition is also met, it indicates that the energy storage component has sufficient charge and can discharge. dev A value less than 0 indicates that the output power provided by the photovoltaic module cannot meet the load demand; the real-time photovoltaic output power P in the third condition is met. pv A value of 0 indicates that the photovoltaic modules are unable to supply power, therefore, the energy storage modules can only provide the power required for the load to operate.

[0079] After the fourth condition mentioned above is met, the second discharge mode will be executed, in which the energy storage component provides the required power to the load.

[0080] Obtain the real-time capacitor voltage V in the second DC-DC converter circuit dc2 The real-time capacitor voltage V dc2 Second voltage setpoint V set2 Input the second voltage loop regulator to obtain the fourth current setpoint I. set4 .

[0081] It also obtains the real-time energy storage component current threshold I corresponding to the real-time remaining power SOC. limt The real-time energy storage component current threshold I limt and the fourth current setpoint I output from the second voltage loop regulator. set4 The input is sent to selector 4, which selects the smaller of the two values ​​as the current setpoint I for the second current loop regulator. * 2, and set the current value I. * 2. The real-time feedback current I1 obtained from the first DC-DC converter circuit is input to the second current loop regulator, and the first duty cycle D1 is output through the second current loop regulator.

[0082] The first duty cycle D1 is input to the PWM output module. The PWM output module generates a first PWM signal based on the first duty cycle D1 and sends it to the first DC-DC converter circuit. The first PWM signal is used to control the switching state of the switching transistor in the first DC-DC converter circuit, thereby realizing the discharge control of the energy storage component.

[0083] For the meaning of each parameter, the method of obtaining it, and the structure of each regulator in this embodiment, please refer to the description of the above embodiments.

[0084] In the energy storage control process of this embodiment, when determining whether to execute the second discharge mode, the real-time photovoltaic output power of the photovoltaic module and the real-time remaining power of the energy storage module are used as judgment parameters. The charging current is also determined based on the real-time remaining power of the energy storage module. This can improve the energy utilization rate of the photovoltaic-energy storage system, reduce the number of discharges and discharge impacts of the energy storage module, improve the reliability and service life of the energy storage module, and thus improve the performance of the photovoltaic-energy storage system.

[0085] In other embodiments of this application, the energy storage control method for a photovoltaic-energy storage system simultaneously includes a first charging mode, a second charging mode, a first discharging mode, and a second discharging mode. The execution conditions and control processes for each mode are described in the foregoing embodiments.

[0086] Figure 5 shows a control block diagram of a fourth embodiment of the photovoltaic-energy storage system energy storage control method of the present invention. Specifically, it is a control block diagram for performing maximum power point tracking of photovoltaic modules.

[0087] Referring to the structural block diagram in Figure 1, the control method of this embodiment includes:

[0088] Obtain the real-time photovoltaic output current I of the photovoltaic module pv and real-time photovoltaic output voltage U pv The values ​​of each parameter are obtained using methods from relevant technologies, which will not be specifically limited or elaborated upon here.

[0089] The real-time photovoltaic output current I pv and real-time photovoltaic output voltage U pv The input is sent to the MPPT controller to perform maximum power point tracking control and obtain the fifth current setpoint I. set5 The MPPT controller performs maximum power point tracking of the output current setpoint, which is achieved using methods from related technologies, but will not be specifically limited or elaborated here.

[0090] The fifth current setpoint I set5 The real-time feedback current I2 from the second DC-DC converter circuit is input to the third current loop regulator to obtain the second duty cycle D2. The real-time feedback current I1 from the first DC-DC converter circuit is obtained using methods from related technologies, which are not specifically limited or described in detail here. The first current loop regulator can be a regulator from related technologies, such as a PI regulator, a PID regulator, or a P regulator. This embodiment does not limit the specific implementation of the first current loop regulator.

[0091] The second duty cycle D2 is input to the PWM output module. The PWM output module generates a second PWM signal based on the second duty cycle D2 and sends it to the second DC-DC converter circuit. The second PWM signal is used to control the switching state of the switching transistor in the second DC-DC converter circuit, thereby achieving maximum power point tracking of the photovoltaic module and improving energy utilization.

[0092] In some embodiments, the real-time energy storage component current threshold I corresponding to the real-time remaining power SOC is obtained. limt This is achieved by querying a data recording table. In this implementation, the data recording table records the remaining power and its corresponding energy storage component current threshold in a discrete manner. If the real-time remaining power SOC is not recorded in the data recording table, the energy storage component current threshold I corresponding to the closest remaining power value in the data recording table can be used. limt replace.

[0093] In other embodiments, the real-time energy storage component current threshold I corresponding to the real-time remaining power SOC is obtained. limt It is obtained through relational calculations, specifically including:

[0094] Obtain the relationship between the remaining capacity of the energy storage module and the current threshold. Calculate the real-time current threshold I of the energy storage module based on this relationship and the real-time remaining capacity (SOC). limt The relation can be selected and set as needed.

[0095] Figure 6 shows a schematic diagram of the charging relationship between the remaining power and the current threshold in one embodiment of the energy storage control method of the photovoltaic energy storage system of the present invention.

[0096] As shown in Figure 6, the charging relationship in this embodiment includes:

[0097] When the remaining power is less than or equal to the third power threshold SOC3, the current threshold is always the first current threshold I. limt1 ;

[0098] When the remaining battery power is greater than or equal to the first battery power threshold SOC max At that time, the current threshold is always the second current threshold I. limt2 ;

[0099] The remaining battery level is greater than the third battery threshold SOC3 and less than the first battery threshold SOC. max When the current threshold is between the first current threshold I limt1 Second current threshold I limt2 Furthermore, the current threshold and the remaining power are negatively correlated. In some embodiments, the negative correlation is an inverse proportional relationship.

[0100] Among them, the third power threshold SOC3 is greater than the second power threshold SOC.min Furthermore, the third battery threshold SOC3 is less than the first battery threshold SOC. max The first current threshold I limt1 Greater than the second current threshold I limt2 .

[0101] Energy storage control is achieved by using the current threshold of the energy storage component determined by the charging relationship formula in the above embodiment. When the remaining power is low, a larger current threshold is provided to allow charging with a larger current; when the remaining power is high, a smaller current threshold is provided to allow charging with a smaller current; when the remaining power is in the middle range, the current threshold is adjusted in a timely manner according to the real-time remaining power so as to adjust the charging current in a timely manner. As a result, the charging frequency of the energy storage component can be reduced, the charging impact can be reduced, and the service life of the energy storage component can be improved.

[0102] Figure 7 shows a schematic diagram of the discharge relationship between remaining power and current threshold in one embodiment of the energy storage control method for the photovoltaic energy storage system of the present invention.

[0103] As shown in Figure 7, the discharge relationship in this embodiment includes:

[0104] When the remaining charge is less than or equal to the fourth charge threshold SOC4, the current threshold is always the third current threshold I. limt3 ;

[0105] When the remaining charge is greater than or equal to the fifth charge threshold SOC5, the current threshold is always the fourth current threshold I. limt4 ;

[0106] When the remaining battery power is greater than the fourth battery power threshold SOC4 and less than the fifth battery power threshold SOC5, the current threshold is between the third current threshold I. limt3 and the fourth current threshold I limt4 The current threshold and the remaining power are positively correlated. In some embodiments, the positive correlation is a direct proportional relationship.

[0107] Among them, the fourth power threshold SOC4 is greater than the second power threshold SOC. min The fifth battery threshold SOC5 is greater than the fourth battery threshold SOC4, and the fifth battery threshold is less than the first battery threshold SOC. max Third current threshold I limt3 Less than the fourth current threshold I limt4 .

[0108] Energy storage control is achieved by using the current threshold of the energy storage module determined by the discharge relationship formula in the above embodiment. When the remaining power is low, a smaller current threshold is provided to allow discharge with a smaller current; when the remaining power is high, a larger current threshold is provided to allow discharge with a larger current; when the remaining power is in the middle range, the current threshold is adjusted in a timely manner according to the real-time remaining power so as to adjust the discharge current in a timely manner. As a result, the discharge frequency of the energy storage module can be reduced, the discharge impact can be reduced, and the service life of the energy storage module can be improved.

[0109] Other embodiments of the present invention also provide a computer storage medium storing a computer program. When the computer program is executed by a processor, it implements the energy storage control method of the optical energy storage system described above and achieves the technical effects of the corresponding embodiments.

[0110] The aforementioned computer storage media can be implemented using any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The computer storage media can be any available storage medium accessible to general-purpose or special-purpose computers.

[0111] In some embodiments, a computer storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Alternatively, the storage medium can be an integral part of the processor. Both the processor and the storage medium can reside in application-specific integrated circuits (ASICs). Of course, the processor and storage medium can also exist as discrete components in the device.

[0112] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by the present invention.

Claims

1. A method for controlling energy storage in a photovoltaic-energy storage system, characterized in that, The photovoltaic-energy storage system includes photovoltaic modules and energy storage modules. The energy storage modules are connected to a DC bus via a first DC-DC converter circuit, and the photovoltaic modules are connected to the DC bus via a second DC-DC converter circuit. The control method includes: The real-time photovoltaic output power of the photovoltaic module, the real-time load power of the load connected to the DC bus, and the real-time remaining power of the energy storage module are obtained. The difference between the real-time photovoltaic output power and the real-time load power is obtained as the real-time power difference; When the first condition is met, the first charging mode is executed; The first condition includes: the real-time remaining power is less than a first power threshold, the real-time power difference is greater than 0, and the real-time load power is greater than 0; The first charging mode includes: The real-time power difference and the energy storage component power threshold are input into the power loop regulator to obtain the first current setpoint; the real-time energy storage component current threshold corresponding to the real-time remaining power is obtained, and the smaller value between the first current setpoint and the real-time energy storage component current threshold is determined as the second current setpoint; Obtain the real-time capacitor voltage in the first DC-DC converter circuit, and input the real-time capacitor voltage and the first voltage setpoint value into the first voltage loop regulator to obtain the third current setpoint value; The smaller of the second current setpoint and the third current setpoint is determined as the current setpoint of the first current loop regulator. The current setpoint of the first current loop regulator and the real-time feedback current in the first DC-DC converter circuit are input into the first current loop regulator to obtain the first duty cycle. A first PWM signal is generated based on the first duty cycle, and the switching transistor in the first DC-DC converter circuit is controlled based on the first PWM signal.

2. The energy storage control method for a photovoltaic energy storage system according to claim 1, characterized in that, The control method further includes: When the second condition is met, the second charging mode is executed; The second condition includes: the real-time remaining power is less than the first power threshold, the real-time power difference is greater than 0, and the real-time load power is equal to 0; The second charging mode includes: Obtain the real-time capacitor voltage in the first DC-DC converter circuit, and input the real-time capacitor voltage and the first voltage setpoint into the first voltage loop regulator to obtain the third current setpoint. Obtain the real-time energy storage component current threshold corresponding to the real-time remaining power, determine the smaller value between the third current setpoint and the real-time energy storage component current threshold as the current setpoint of the first current loop regulator, and input the current setpoint of the first current loop regulator and the real-time feedback current in the first DC-DC conversion circuit to the first current loop regulator to obtain the first duty cycle; The first PWM signal is generated according to the first duty cycle, and the switching transistor in the first DC-DC converter circuit is controlled according to the first PWM signal.

3. The energy storage control method for a photovoltaic energy storage system according to claim 1, characterized in that, The control method further includes: When the third condition is met, the first discharge mode is executed; The third condition includes: the real-time remaining power is greater than the second power threshold, the real-time power difference is less than 0, and the real-time photovoltaic output power is greater than 0; the second power threshold is less than the first power threshold; The first discharge mode includes: The absolute value of the real-time power difference is compared with the load power change threshold; When the absolute value of the real-time power difference is less than or equal to the load power change threshold, the energy storage component is controlled to stop discharging. When the absolute value of the real-time power difference is greater than the load power change threshold, the real-time capacitor voltage in the second DC-DC converter circuit is obtained, and the real-time capacitor voltage and the second voltage setpoint value in the second DC-DC converter circuit are input to the second voltage loop regulator to obtain the fourth current setpoint value. Obtain the real-time energy storage component current threshold corresponding to the real-time remaining power, determine the smaller value between the fourth current setpoint and the real-time energy storage component current threshold as the current setpoint of the second current loop regulator, and input the current setpoint of the second current loop regulator and the real-time feedback current in the first DC-DC conversion circuit into the second current loop regulator to obtain the first duty cycle; The first PWM signal is generated according to the first duty cycle, and the switching transistor in the first DC-DC converter circuit is controlled according to the first PWM signal.

4. The energy storage control method for a photovoltaic energy storage system according to claim 3, characterized in that, The control method further includes: When the fourth condition is met, the second discharge mode is executed; The fourth condition includes: the real-time remaining power is greater than the second power threshold, the real-time power difference is less than 0, and the real-time photovoltaic output power is equal to 0; The second discharge mode includes: Obtain the real-time capacitor voltage in the second DC-DC converter circuit, and input the real-time capacitor voltage and the second voltage setpoint value into the second voltage loop regulator to obtain the fourth current setpoint value; Obtain the real-time energy storage component current threshold corresponding to the real-time remaining power, determine the smaller value between the fourth current setpoint and the real-time energy storage component current threshold as the current setpoint of the second current loop regulator, and input the current setpoint of the second current loop regulator and the real-time feedback current in the first DC-DC conversion circuit into the second current loop regulator to obtain the first duty cycle; The first PWM signal is generated according to the first duty cycle, and the switching transistor in the first DC-DC converter circuit is controlled according to the first PWM signal.

5. The energy storage control method for a photovoltaic energy storage system according to claim 3, characterized in that, Obtaining the real-time energy storage component current threshold corresponding to the real-time remaining power specifically includes: Obtain the relationship between the remaining power of the energy storage component and the current threshold, and calculate the real-time current threshold of the energy storage component based on the relationship and the real-time remaining power.

6. The energy storage control method for a photovoltaic energy storage system according to claim 5, characterized in that, The relationship between the remaining power of the energy storage component and the current threshold includes a charging relationship and a discharging relationship; The charging relationship includes: When the remaining power is less than or equal to the third power threshold, the current threshold is always the first current threshold; When the remaining power is greater than or equal to the first power threshold, the current threshold is always the second current threshold; When the remaining power is greater than the third power threshold and less than the first power threshold, the current threshold is between the first current threshold and the second current threshold, and the current threshold is negatively correlated with the remaining power. The third power threshold is greater than the second power threshold, the third power threshold is less than the first power threshold, and the first current threshold is greater than the second current threshold. The discharge relationship includes: When the remaining power is less than or equal to the fourth power threshold, the current threshold is always the third current threshold; When the remaining power is greater than or equal to the fifth power threshold, the current threshold is always the fourth current threshold; When the remaining power is greater than the fourth power threshold and less than the fifth power threshold, the current threshold is between the third current threshold and the fourth current threshold, and the current threshold is positively correlated with the remaining power. The fourth power threshold is greater than the second power threshold, the fifth power threshold is greater than the fourth power threshold, the fifth power threshold is less than the first power threshold, and the third current threshold is less than the fourth current threshold.

7. The energy storage control method for a photovoltaic-energy storage system according to any one of claims 1 to 6, characterized in that, The method further includes: Obtain the real-time photovoltaic output current and real-time photovoltaic output voltage of the photovoltaic module; Based on the real-time photovoltaic output current and real-time photovoltaic output voltage, maximum power point tracking control is performed to obtain the fifth current setpoint; The fifth current setpoint and the real-time feedback current obtained in the second DC-DC converter circuit are input into the third current loop regulator to obtain the second duty cycle; A second PWM signal is generated based on the second duty cycle, and the switching transistor in the second DC-DC converter circuit is controlled based on the second PWM signal.

8. A photovoltaic energy storage system energy storage control device, characterized in that, The photovoltaic-energy storage system includes photovoltaic modules and energy storage modules. The energy storage modules are connected to a DC bus via a first DC-DC converter circuit, and the photovoltaic modules are connected to the DC bus via a second DC-DC converter circuit. The control device includes: A controller is connected to the first DC-DC conversion circuit and the second DC-DC conversion circuit respectively, and is configured to execute the energy storage control method of the photovoltaic energy storage system according to any one of claims 1 to 7.

9. A photovoltaic energy storage system, characterized in that, The system includes photovoltaic modules and energy storage modules. The energy storage modules are connected to a DC bus via a first DC-DC converter circuit, and the photovoltaic modules are connected to the DC bus via a second DC-DC converter circuit. The photovoltaic-energy storage system also includes the energy storage control device for the photovoltaic-energy storage system as described in claim 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the energy storage control method for the photovoltaic energy storage system as described in any one of claims 1 to 7.

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