Hybrid inverter control method, controller and energy storage system

Abstract

The invention discloses a control method of a hybrid inverter, a controller and an energy storage system, the control method of the hybrid inverter, a low-voltage battery system comprises a low-voltage battery and a first DCDC module connected with the low-voltage battery, the hybrid inverter comprises a second DCDC module connected with a DC bus, the second DCDC module is suitable for being connected with the first DCDC module, and the second DCDC module is suitable for being connected with the second DCDC module. The second DCDC module is also suitable for communicating with the first DCDC module through a hard wire signal, and the control method of the hybrid inverter comprises the following steps: under the condition that the low-voltage battery system meets a preset starting condition, controlling the second DCDC module to start, and sending a quick starting instruction to the first DCDC module through the hard wire signal, the first DCDC module and the second DCDC module are started synchronously based on the quick start instruction. According to the method, synchronous starting of the first DCDC module of the low-voltage battery system and the second DCDC module of the hybrid inverter can be achieved, the discharging response speed of the low-voltage battery system is increased, the energy requirement of a direct-current bus is rapidly met, and the system is made to operate stably.

Description

Technical Field

[0001] This invention relates to the field of energy storage system technology, and in particular to a control method for a hybrid inverter, a controller, and an energy storage system. Background Technology

[0002] With the escalating energy crisis in Europe and supportive domestic policies, photovoltaic (PV) and energy storage (ESS) systems have experienced rapid development. These systems comprise photovoltaic modules, energy storage batteries, and energy storage converters. The control strategy for PV-ESS systems is as follows: when the energy output from the photovoltaic modules is sufficient to support the energy demand of the energy storage converter, the energy storage batteries are kept in standby mode to conserve energy. However, when it is determined that the energy output from the photovoltaic modules is insufficient to support the energy demand of the energy storage converter, the converter outputs a corresponding communication signal to the energy storage batteries based on the assessment result. The energy storage batteries then activate based on the recognition of this communication signal to replenish energy.

[0003] However, the energy storage battery of this technology has a slow start-up speed, and when the energy output of the photovoltaic module cannot support the output energy demand of the energy storage converter due to a sudden increase in load, it can easily cause the entire system to collapse. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, the first objective of this invention is to propose a control method for a hybrid inverter that enables the synchronous startup of the first DC-DC (Direct Current-Direct Current) module of the low-voltage battery system and the second DC-DC module of the hybrid inverter, thereby improving the discharge response speed of the low-voltage battery system to quickly support the energy demand of the DC bus and ensure stable operation of the energy storage system.

[0005] The second objective of this invention is to provide a controller.

[0006] The third objective of this invention is to provide an energy storage system.

[0007] To achieve the above objectives, a first aspect of the present invention provides a control method for a hybrid inverter. The hybrid inverter is adapted to connect to a low-voltage battery system, the low-voltage battery system including a low-voltage battery and a first DC-DC module connected to the low-voltage battery, and the hybrid inverter including a second DC-DC module connected to a DC bus. The second DC-DC module is adapted to connect to the first DC-DC module, and the second DC-DC module is also adapted to communicate with the first DC-DC module via a hard-wired signal. The control method for the hybrid inverter includes: controlling the second DC-DC module to start when the low-voltage battery system meets preset start-up conditions, and sending a fast start command to the first DC-DC module via a hard-wired signal, so that the first DC-DC module starts synchronously with the second DC-DC module based on the fast start command.

[0008] According to the control method of the hybrid inverter of the present invention, the hybrid inverter is adapted to be connected to a low-voltage battery system, and the second DC-DC module of the hybrid inverter is adapted to be connected to the first DC-DC module of the low-voltage battery system. The second DC-DC module is also adapted to communicate with the first DC-DC module via a hard-wired signal. When the low-voltage battery system meets preset startup conditions, the method controls the second DC-DC module to start and sends a fast startup command to the first DC-DC module via a hard-wired signal, so that the first DC-DC module starts synchronously with the second DC-DC module based on the fast startup command. Therefore, this method can achieve synchronous startup of the first DC-DC module of the low-voltage battery system and the second DC-DC module of the hybrid inverter, improving the discharge response speed of the low-voltage battery system to quickly support the DC bus energy demand and ensure stable operation of the energy storage system.

[0009] In addition, the control method for the hybrid inverter according to the above embodiments of the present invention may also have the following additional technical features:

[0010] According to one embodiment of the present invention, the hybrid inverter further includes a DCAC (Direct Current-Alternating Current) module, the DC side of which is connected to the DC bus, and the AC side of which is adapted to connect to a load. The low-voltage battery system is determined to meet the preset startup conditions by: acquiring the DC bus voltage of the DC bus while controlling the DCAC module to operate and supply power to the load; acquiring the voltage difference between the DC bus reference voltage and the DC bus voltage; and determining that the low-voltage battery system meets the preset startup conditions if the voltage difference is greater than a first preset voltage difference.

[0011] According to one embodiment of the present invention, after the first DC-DC module and the second DC-DC module are started synchronously, the method further includes: determining the load power demand of the load; obtaining the product of the load power demand, the voltage difference and the preset voltage-power conversion coefficient to obtain a first power, and obtaining the sum of the first power and the preset power margin to obtain the output power of the second DC-DC module.

[0012] According to one embodiment of the present invention, after the first DC-DC module and the second DC-DC module are started synchronously, the control method further includes: obtaining the absolute value of the voltage difference between the DC bus reference voltage and the DC bus voltage; and controlling the second DC-DC module and the first DC-DC module to maintain their current working state when the absolute value of the voltage difference is less than a second preset voltage difference.

[0013] According to one embodiment of the present invention, the hybrid inverter further includes a third DC-DC module, one end of which is connected to the DC bus, and the other end of which is adapted to connect to a new energy power generation device. The control method further includes controlling the third DC-DC module to operate so that the new energy power generation device supplies power to the load through the third DC-DC module and the DC-AC module.

[0014] According to one embodiment of the present invention, the hybrid inverter is further adapted to be connected to a high-voltage battery system, the high-voltage battery system including a high-voltage battery, and the second DC-DC module is further adapted to be connected to the high-voltage battery. The control method further includes: responding to the access signal of the target battery system and sending an identification information acquisition instruction to the target battery system; wherein the target battery system is a low-voltage battery system or a high-voltage battery system; responding to the response instruction with identification information sent by the target battery system, acquiring the identification information, and acquiring a control program corresponding to the target battery system based on the identification information; and controlling the target battery system based on the control program.

[0015] To achieve the above objectives, a second aspect of the present invention provides a controller, including a memory, a processor, and a control program for a hybrid inverter stored in the memory and executable on the processor. When the processor executes the control program for the hybrid inverter, it implements the above-described control method for the hybrid inverter.

[0016] According to the controller of the present invention, when the processor executes the control program of the hybrid inverter, the above-mentioned control method of the hybrid inverter is implemented. Based on the above-mentioned control method of the hybrid inverter, the first DC-DC module of the low-voltage battery system and the second DC-DC module of the hybrid inverter can be started synchronously, thereby improving the discharge response speed of the low-voltage battery system, so as to quickly support the energy demand of the DC bus and enable the energy storage system to operate stably.

[0017] To achieve the above objectives, a third aspect of the present invention provides an energy storage system, comprising: a low-voltage battery system or a high-voltage battery system, wherein the low-voltage battery system includes a low-voltage battery and a first DC-DC module connected to the low-voltage battery, and the high-voltage battery system includes a high-voltage battery; a hybrid inverter, wherein the hybrid inverter includes a second DC-DC module connected to a DC bus and a controller, the second DC-DC module being further adapted to connect to the first DC-DC module or the high-voltage battery, and the second DC-DC module being further adapted to communicate with the first DC-DC module via a hard-wired signal; wherein the controller is used to control the second DC-DC module to start when the low-voltage battery system meets preset start-up conditions, and to send a fast start command to the first DC-DC module via a hard-wired signal, so that the first DC-DC module starts synchronously with the second DC-DC module based on the fast start command.

[0018] According to an embodiment of the energy storage system of the present invention, when the energy storage system includes a low-voltage battery system, the low-voltage battery system includes a low-voltage battery and a first DC-DC converter module connected to the low-voltage battery. The hybrid inverter includes a second DC-DC converter module connected to the DC bus and a controller. The second DC-DC converter module is also adapted to connect to the first DC-DC converter module and is also adapted to communicate with the first DC-DC converter module via a hard-wired signal. When the low-voltage battery system meets preset startup conditions, the controller controls the second DC-DC converter module to start and sends a fast startup command to the first DC-DC converter module via a hard-wired signal, so that the first DC-DC converter module starts synchronously with the second DC-DC converter module based on the fast startup command. When the energy storage battery includes a high-voltage battery system, the high-voltage battery system includes a high-voltage battery, and the second DC-DC converter module connected to the DC bus in the hybrid inverter is also adapted to connect to the high-voltage battery. Thus, the energy storage system can realize the synchronous startup of the first DC-DC converter module of the low-voltage battery system and the second DC-DC converter module of the hybrid inverter, improve the discharge response speed of the low-voltage battery system, quickly support the energy demand of the DC bus, and enable the energy storage system to operate stably.

[0019] In addition, the energy storage system according to the above embodiments of the present invention may also have the following additional technical features:

[0020] According to one embodiment of the present invention, the hybrid inverter further includes a DCAC module, the DC side of which is connected to a DC bus, and the AC side of which is adapted to connect to a load. The controller is further configured to: acquire the DC bus voltage of the DC bus and acquire the voltage difference between the DC bus reference voltage and the DC bus voltage during the process of controlling the DCAC module to operate to supply power to the load; and determine that the low-voltage battery system meets the preset start-up conditions when the voltage difference is greater than a first preset voltage difference.

[0021] According to one embodiment of the present invention, the controller is further configured to: after the first DC-DC module and the second DC-DC module are started synchronously, determine the load demand power of the load, obtain the product of the load demand power, the voltage difference and the preset voltage-power conversion coefficient to obtain the first power, and obtain the sum of the first power and the preset power margin to obtain the output power of the second DC-DC module.

[0022] According to one embodiment of the present invention, the controller is further configured to: after the first DC-DC module and the second DC-DC module are started synchronously, acquire the absolute value of the voltage difference between the DC bus reference voltage and the DC bus voltage, and control the second DC-DC module and the first DC-DC module to maintain the current working state if the absolute value of the voltage difference is less than a second preset voltage difference.

[0023] According to one embodiment of the present invention, the hybrid inverter further includes a third DC-DC module, one end of which is connected to the DC bus, and the other end of which is adapted to connect to a new energy power generation device. The controller is also used to control the operation of the third DC-DC module so that the new energy power generation device supplies power to the load through the third DC-DC module and the DC-AC module.

[0024] According to one embodiment of the present invention, the controller is further configured to: respond to the access signal of the target battery system and send an identification information acquisition instruction to the target battery system; wherein the target battery system is a low-voltage battery system or a high-voltage battery system; respond to the response instruction with identification information sent by the target battery system, acquire the identification information, and acquire a control program corresponding to the target battery system based on the identification information; and control the target battery system based on the control program.

[0025] According to one embodiment of the present invention, a hybrid inverter includes a plurality of DCAC modules of the plurality of hybrid inverters connected in parallel on the AC side.

[0026] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0027] Figure 1 A flowchart of a control method for a hybrid inverter according to an embodiment of the present invention;

[0028] Figure 2 A schematic diagram of the architecture of an energy storage system according to an embodiment of the present invention. Figure 1 ;

[0029] Figure 3 A schematic diagram of the architecture of an energy storage system according to an embodiment of the present invention. Figure 2 ;

[0030] Figure 4 A schematic diagram of the architecture of an energy storage system according to an embodiment of the present invention. Figure 3 ;

[0031] Figure 5 A flowchart of an adaptive matching control method for a hybrid inverter according to a specific embodiment of the present invention;

[0032] Figure 6 This is a flowchart of a control method for a hybrid inverter according to a specific embodiment of the present invention;

[0033] Figure 7 This is a block diagram of a controller according to an embodiment of the present invention;

[0034] Figure 8 This is a connection diagram of architecture 1 in the related technology;

[0035] Figure 9 This is a connection diagram of architecture 2 in the related technology;

[0036] Figure 10 This is a connection diagram of architecture 3 in the related technologies;

[0037] Figure 11 This is a connection diagram of architecture 4 in the related technologies;

[0038] Figure 12 This is a schematic diagram of an energy storage system architecture according to an embodiment of the present invention, where the energy storage system includes a low-voltage battery system. Figure 1 ;

[0039] Figure 13 This is a schematic diagram of an energy storage system architecture according to an embodiment of the present invention, where the energy storage system includes a high-voltage battery system. Figure 1 ;

[0040] Figure 14 This is a schematic diagram of an energy storage system architecture according to an embodiment of the present invention, where the energy storage system includes a low-voltage battery system. Figure 2 ;

[0041] Figure 15 This is a schematic diagram of an energy storage system architecture according to an embodiment of the present invention, where the energy storage system includes a high-voltage battery system. Figure 2 . Detailed Implementation

[0042] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0043] The control method, controller, and energy storage system for the hybrid inverter proposed in this invention are described below with reference to the accompanying drawings.

[0044] Figure 1 This is a flowchart of a control method for a hybrid inverter according to an embodiment of the present invention.

[0045] like Figure 2 As shown, in one embodiment of the present invention, the hybrid inverter 10 is adapted to connect to a low-voltage battery system 20, the low-voltage battery system 20 including a low-voltage battery 21 and a first DC-DC module 22 connected to the low-voltage battery 21, the hybrid inverter 10 including a second DC-DC module 11 connected to a DC bus, the second DC-DC module 11 being adapted to connect to the first DC-DC module 22, and the second DC-DC module 11 being adapted to communicate with the first DC-DC module 22 via a hardwired signal.

[0046] Specifically, taking a photovoltaic energy storage system as an example, the DC side of the hybrid inverter 10 is connected to the photovoltaic modules and battery system, and the AC side of the hybrid inverter 10 is connected to the load and the AC grid, wherein the photovoltaic modules and battery system are both connected to the DC bus of the hybrid inverter 10.

[0047] The hybrid inverter 10 can be connected to either a high-voltage battery system or a low-voltage battery system, and includes a second DC-DC module 11, a control sampling module, etc. When the hybrid inverter 10 is connected to the low-voltage battery system 20, such as... Figure 2 As shown, the low-voltage battery 21 in the low-voltage battery system 20 is first connected to the first DC-DC module 22, and then the first DC-DC module 22 is connected to the second DC-DC module 11 to complete the connection between the low-voltage battery system 20 and the hybrid inverter 10. When both the first DC-DC module 22 and the second DC-DC module 11 are in the startup state, the energy in the low-voltage battery 20 can be output to the DC bus. The low-voltage battery system 20 and the hybrid inverter 10 have power interfaces, communication interfaces, and hardware signal interfaces. That is, the second DC-DC module 11 can be connected to the first DC-DC module 22 through the power interface, communication interface, and hardware signal interface. In addition to communicating with the first DC-DC module 22 through the communication interface, the second DC-DC module 11 can also communicate quickly through hardware signals based on the hardware signal interface. The specific communication division can be determined according to the situation.

[0048] The hybrid inverter 10 is compatible with both high-voltage and low-voltage battery systems 20. Figure 2 This is merely a schematic diagram illustrating the connection between the hybrid inverter 10 and the low-voltage battery system 20. Furthermore, the first DC-DC module 22 in this low-voltage battery system 20 has low technical difficulty, a short development cycle, and reduces application costs.

[0049] like Figure 1As shown, the control method for a hybrid inverter according to an embodiment of the present invention includes:

[0050] S1, when the low-voltage battery system meets the preset startup conditions, control the second DC-DC module to start, and send a fast startup command to the first DC-DC module through a hard-wired signal, so that the first DC-DC module starts synchronously with the second DC-DC module based on the fast startup command.

[0051] Specifically, during operation, if the output energy of the photovoltaic modules is sufficient to support the output energy demand of the hybrid inverter, the second DC-DC module and the first DC-DC module are controlled to enter standby mode to save energy consumption of the low-voltage battery.

[0052] When the output energy of the photovoltaic modules cannot support the output energy demand of the hybrid inverter at a certain moment—for example, when a large load is suddenly connected to the AC side of the energy storage inverter, and the total load after connection exceeds the total power generation of the photovoltaic modules—the low-voltage battery system needs to supplement the DC bus of the hybrid inverter to prevent the entire system from collapsing. In this case, if the low-voltage battery system meets the preset startup conditions, the hybrid inverter controller controls the second DC-DC converter to start. Simultaneously, it sends a fast-start command to the first DC-DC converter via a hardware signal interface, causing the first and second DC-DC converters to start synchronously. This allows the low-voltage battery to quickly output energy based on the started first and second DC-DC converters, supplementing the DC bus of the hybrid inverter and preventing the entire system from collapsing. At this time, power is supplied simultaneously by the photovoltaic modules and the low-voltage battery.

[0053] The hardware signal interface is an I / O interface, and the hardware signals are high-level signals and low-level signals. For example, when the hardware signal is high-level, it is a fast start instruction; when the hardware signal is low-level, it is a standby instruction. So, the first DC-DC module performs fast start when it receives a high-level signal, and stops working when it receives a low-level signal.

[0054] It should be further noted that the DC-DC module in this application can be a DC-DC converter such as LLC, DAB, BUCK, or BOOST, and the hardware signal can be in the form of dry contact, level signal conversion, level toggling, button, etc., without any specific limitations.

[0055] Therefore, this embodiment can realize the synchronous start-up of the first DC-DC module and the second DC-DC module based on hardware signals, meet the needs of quickly supporting DC bus energy, avoid the occurrence of system collapse due to slow energy replenishment speed, improve the system's operational stability, and enable the system to have the function of dynamic switching under large loads.

[0056] In one embodiment of the present invention, the hybrid inverter further includes a DCAC module, the DC side of which is connected to the DC bus, and the AC side of which is adapted to connect to a load. The low-voltage battery system is determined to meet the preset startup conditions by: acquiring the DC bus voltage V1 during the process of controlling the DCAC module to operate and supply power to the load; acquiring the voltage difference ΔVDC between the DC bus reference voltage Vref and the DC bus voltage V1; and determining that the low-voltage battery system meets the preset startup conditions if the voltage difference ΔVDC is greater than a first preset voltage difference c.

[0057] Specifically, with Figure 3 Taking the photovoltaic energy storage system shown as an example, the new energy power generation device 30 is a photovoltaic module. Both the new energy power generation device 30 and the low-voltage battery system 20 are connected to the DC bus of the hybrid inverter 10. When the DCAC module 12 supplies power to the load, the DCAC module 12 directly draws DC power from the DC bus and converts the DC power into AC power before outputting it to supply power to the load. The DC bus serves as the energy aggregation channel for the new energy power generation device 30 and the low-voltage battery system 20.

[0058] During the process of controlling the DCAC module 12 to supply power to the load, if the output energy of the new energy power generation device 30 is sufficient to support the output energy demand of the hybrid inverter 10, i.e., the load demand, then the second DC-DC module 11 and the first DC-DC module 22 are controlled to enter the standby state. At this time, the voltage of the DC bus is the output voltage of the new energy power generation device 30. At the same time, the DC bus voltage V1 is detected, and the voltage difference ΔVDC between the DC bus reference voltage Vref and the DC bus voltage V1 is obtained. If it is determined that the voltage difference ΔVDC is greater than the first preset voltage difference c, it is considered that the output energy of the new energy power generation device 30 cannot support the output energy demand of the hybrid inverter 10. It is determined that the low-voltage battery system 20 meets the preset start-up conditions, then the second DC-DC module 11 is controlled to start, and at the same time, a fast start command is sent to the first DC-DC module 22 based on hardware signals through the hardware signal interface, so that the first DC-DC module 22 starts synchronously with the second DC-DC module 11 based on the fast start command, and the low-voltage battery 21 replenishes the DC bus with energy. If the voltage difference ΔVDC is determined to be less than or equal to the first preset voltage difference c, it is considered that the output energy of the new energy power generation device 30 can support the output energy demand of the hybrid inverter 10, and the second DC-DC module and the first DC-DC module continue to be controlled to remain in standby mode.

[0059] Therefore, this embodiment determines whether the preset start-up conditions have been met based on voltage comparison, eliminating the need for the lengthy process of calculating and comparing power in software, thus further improving the start-up response speed.

[0060] In one embodiment of the present invention, after the first DC-DC module and the second DC-DC module are started synchronously, the method further includes: determining the load demand power Pac of the load; obtaining the product of the load demand power Pac, the voltage difference ΔVDC and the preset voltage-power conversion coefficient k to obtain the first power, and obtaining the sum of the first power and the preset power margin x to obtain the output power Pbat of the second DC-DC module.

[0061] Specifically, after the first and second DC-DC modules are started synchronously, the output power of the low-voltage battery system, i.e., the output power Pbat of the second DC-DC module, is determined by the following formula:

[0062] Pbat = k * △VDC * Pac + x

[0063] Where Pbat represents the output power of the second DC-DC module, k represents the preset voltage-to-power conversion coefficient, ΔVDC represents the voltage difference, Pac represents the load power requirement, and x represents the preset power margin. The preset power margin x can be set according to actual conditions and can be 0.

[0064] After determining the output power Pbat of the second DC-DC module according to the above formula, the first and second DC-DC modules are controlled based on the output power Pbat to meet the power supply requirements.

[0065] In one embodiment of the present invention, after the first DC-DC module and the second DC-DC module are started synchronously, the control method further includes: obtaining the absolute value of the voltage difference |ΔVDC| between the DC bus reference voltage Vref and the DC bus voltage V1; and controlling the second DC-DC module and the first DC-DC module to maintain their current working state when the absolute value of the voltage difference |ΔVDC| is less than a second preset voltage difference d.

[0066] In other words, when |△VDC|=|Vref-V1|<d, it is determined that the output power of DCAC module 12 can meet the current load demand power Pac, and the second DC-DC module and the first DC-DC module are controlled to maintain their current operating state to continue supplying power to the load.

[0067] In one embodiment of the present invention, the hybrid inverter 10 further includes a third DC-DC module, one end of which is connected to the DC bus, and the other end of which is adapted to connect to a new energy power generation device. The control method further includes controlling the third DC-DC module to operate so that the new energy power generation device supplies power to the load through the third DC-DC module and the DC-AC module.

[0068] Specifically, in a photovoltaic energy storage system, the new energy power generation device is a photovoltaic module; in a wind power energy storage system, the new energy power generation device is a wind power generation device.

[0069] by Figure 3 Taking the photovoltaic energy storage system shown as an example, the new energy power generation device 30 is a photovoltaic module. The new energy power generation device 30 is connected to the DC bus through the third DC-DC module 13. During the process of powering the load, the third DC-DC module 13 and the DC-AC module 12 are controlled to work simultaneously. The DC power output by the new energy power generation device 30 is converted into the target DC power through the third DC-DC module 13 and output to the DC bus. The DC-AC module 12 takes power from the DC bus and converts it into AC power output to power the load.

[0070] In one embodiment of the present invention, combined with Figure 4 As shown, the hybrid inverter 10 is also adapted to connect to a high-voltage battery system 40, which includes a high-voltage battery 41, and the second DC-DC module 11 is also adapted to connect to the high-voltage battery 41.

[0071] In other words, this hybrid inverter can be adapted to both high-voltage and low-voltage battery systems. For example... Figure 4 As shown, if the high-voltage battery system 40 is used, the second DC-DC module 11 is directly connected to the high-voltage battery 41, that is, the high-voltage battery 41 can be directly connected to the hybrid inverter 10. The high-voltage battery system 40 and the hybrid inverter 10 can be connected through a power interface and a communication interface.

[0072] In one embodiment of the present invention, the control method further includes: responding to an access signal from a target battery system and sending an identification information acquisition instruction to the target battery system; wherein the target battery system is a low-voltage battery system or a high-voltage battery system; responding to a response instruction with identification information sent by the target battery system, acquiring the identification information, and acquiring a control program corresponding to the target battery system based on the identification information; and controlling the target battery system based on the control program. The target battery system is either a high-voltage battery system or a low-voltage battery system.

[0073] Since the hybrid inverter can be connected to both high-voltage and low-voltage battery systems, adaptive identification and matching are required at the installation site after the hybrid inverter is connected to the battery system.

[0074] Specifically, after the target battery system and the hybrid inverter are installed, the staff presses the control button corresponding to the target battery system to send an access signal of the target battery system to the hybrid inverter. The access signal is a signal with level transformation.

[0075] When the hybrid inverter detects a change in the port electrical signal level of the receiving access signal, it determines that it has received the access signal of the target battery system, and sends an identification information acquisition instruction to the first DC-DC module of the high-voltage battery or low-voltage battery system through the communication interface, requesting it to send back a response instruction with identification information marked by the high-voltage battery system or low-voltage battery system.

[0076] After obtaining the identification information according to the response command, the hybrid inverter determines the control program that matches the target battery system and performs an initialization operation to control the target battery system based on this control program. For example, if the identification information of the high-voltage battery system is 1 and the identification information of the low-voltage battery system is 0, when the hybrid inverter determines that the identification information is 1, it performs the initialization operation using the control program corresponding to the high-voltage battery system and uses it for subsequent system control; when the hybrid inverter determines that the identification information is 0, it performs the initialization operation using the control program corresponding to the low-voltage battery system and uses it for subsequent system control.

[0077] Furthermore, the hybrid inverter can also determine whether an access signal has been received based on the duration of the control button press. For example, when the control button is pressed, the port electrical signal level goes high; when the control button is released, the port electrical signal level returns to low. The hybrid inverter starts timing when the port electrical signal level goes high and ends timing when it returns to low. If the timing reaches the set time, the button signal is considered valid, and the access signal from the target battery system has been received; otherwise, the button signal is considered invalid, no access signal from the target battery system has been received, and a feedback signal is sent to the after-sales APP to prompt the installer to press the button again.

[0078] It should be noted that, in addition to sending the target battery system access signal to the hybrid inverter via hardware control buttons as mentioned above, the access signal can also be sent to the hybrid inverter via a mobile app over a communication network. For example, under normal communication conditions, staff can send corresponding control signals to the hybrid inverter via the network through the mobile app to control the entire power supply and energy storage system, enabling functions such as start-up and shutdown. However, when the network infrastructure is disrupted due to force majeure (e.g., war, weather, geological disasters), and control via the mobile app is not possible, staff can manually control the system using control buttons to provide a reliable emergency response. As a specific embodiment of this application, taking the application of a hybrid inverter in a photovoltaic energy storage system, with the DC side connected to the battery system and photovoltaic modules, as an example, the adaptive matching control method of this hybrid inverter is as follows: Figure 5 As shown, the following steps may be included:

[0079] S101, The photovoltaic energy storage system has been installed;

[0080] S102, the photovoltaic module connection switch is closed, and the hybrid inverter is powered on and in standby mode;

[0081] S103, Press the control button for the high-voltage battery / Press the control button for the first DC-DC module;

[0082] S104, the hybrid inverter identifies the control button signal, determines that the access signal has been received, and in response to receiving the access signal, sends an identification information acquisition instruction to the target battery system;

[0083] S105, receive a response command with identification information sent by the target battery system, and obtain the identification information based on the response command;

[0084] S106: Obtain the control program corresponding to the target battery system based on the identification information and initialize it;

[0085] S107, the photovoltaic energy storage system starts up and operates, and the target battery system is controlled based on the control program.

[0086] When the target battery system is a low-voltage battery system, the control method of the hybrid inverter is as follows: Figure 6 As shown, the following steps may be included:

[0087] S201 controls the first and second DC-DC modules to standby mode, and controls the third DC-DC module and DCAC module to work, so as to supply power to the load through the energy provided by the photovoltaic modules;

[0088] S202, obtain the DC voltage V1 of the bus;

[0089] S203, obtain the voltage difference ΔVDC=Vref-V1 between the DC bus reference voltage and the DC bus voltage;

[0090] S204, determine whether the voltage difference ΔVDC is greater than the first preset voltage difference c. If yes, proceed to step S205; if no, proceed to step S202.

[0091] S205 controls the second DC-DC module to start up and sends a fast start command to the first DC-DC module via a hard-wired signal so that the first DC-DC module and the second DC-DC module start up synchronously and supply power to the load simultaneously through the photovoltaic module and the low-voltage battery.

[0092] S206, Determine the load power requirement Pac of the load;

[0093] S207, calculate the power required to be supplemented at the battery terminal Pbat = k * ΔVDC * Pac + x;

[0094] S208 controls the first and second DC-DC modules based on power Pbat;

[0095] S209, Obtain the absolute value of the voltage difference between the DC bus reference voltage and the DC bus voltage |△VDC|=|Vref-V1|;

[0096] S210, determine whether the absolute value of the voltage difference |△VDC| is less than the second preset voltage difference d. If yes, proceed to step S211; if no, proceed to step S206.

[0097] S211, maintain the stable operation of the first and second DC-DC modules in their current working state.

[0098] In summary, according to the control method of the hybrid inverter of the present invention, the hybrid inverter is suitable for connection to a low-voltage battery system, and the second DC-DC module of the hybrid inverter is suitable for connection to the first DC-DC module of the low-voltage battery system. Furthermore, the second DC-DC module is also suitable for communication with the first DC-DC module via a hard-wired signal. When the low-voltage battery system meets preset startup conditions, the method controls the second DC-DC module to start and sends a fast startup command to the first DC-DC module via a hard-wired signal, so that the first DC-DC module starts synchronously with the second DC-DC module based on the fast startup command. Therefore, this method can achieve synchronous startup of the first DC-DC module of the low-voltage battery system and the second DC-DC module of the hybrid inverter, improving the discharge response speed of the low-voltage battery system to quickly support the DC bus energy demand and ensure stable operation of the energy storage system.

[0099] Corresponding to the above embodiments, the present invention also proposes a controller.

[0100] like Figure 7 As shown, the controller 100 of this embodiment includes a memory 110, a processor 120, and a control program for a hybrid inverter stored in the memory 110 and executable on the processor 120. When the processor 120 executes the control program for the hybrid inverter, it implements the above-described control method for the hybrid inverter.

[0101] According to the controller of the present invention, when the processor executes the control program of the hybrid inverter, the above-mentioned control method of the hybrid inverter is implemented. Based on the above-mentioned control method of the hybrid inverter, the first DC-DC module of the low-voltage battery system and the second DC-DC module of the hybrid inverter can be started synchronously, thereby improving the discharge response speed of the low-voltage battery system, so as to quickly support the energy demand of the DC bus and enable the energy storage system to operate stably.

[0102] Corresponding to the above embodiments, the present invention also proposes an energy storage system.

[0103] As a new type of clean energy, wind and solar energy will become the absolute main energy source in the future. However, due to the discontinuous, unstable and uncontrollable characteristics of renewable energy power generation such as wind and solar power, large-scale grid connection will seriously impact the safe and stable operation of the grid. Therefore, energy storage technology, as one of the important supporting technologies, is an important means to smooth out the fluctuations of new energy and reduce the impact of large-scale new energy access on the grid.

[0104] In recent years, with the escalating energy crisis in Europe and the support of domestic policies, residential photovoltaic and energy storage systems have developed rapidly. Currently, the residential photovoltaic and energy storage market offers a variety of product forms. In terms of form, they can be divided into integrated units and split units. In terms of the number of AC output phases, they can be divided into single-phase products and three-phase products. In terms of the voltage range of the energy storage batteries, they can be divided into low-voltage battery products and high-voltage battery products. The variety is extensive, and each type has its own advantages.

[0105] Throughout the entire lifecycle of a photovoltaic energy storage system, including product development, sales, and maintenance, all stakeholders, including suppliers, customers, and installers, desire a product that is compatible with a wider range of application scenarios to facilitate storage, management, and maintenance. Currently, most system architectures on the market cannot meet the requirement of adapting high-voltage and low-voltage battery systems to the same inverter. Customers need to place orders separately, and significant human, material, and financial resources are required for transportation, storage, and management.

[0106] Currently, products on the market are mainly divided into the following architectures:

[0107] 1) Architecture 1: Low-voltage battery + DC-DC converter + inverter, such as Figure 8 As shown, however, this architecture only supports low-voltage battery systems and cannot use high-voltage battery systems, resulting in high costs, weak competitiveness, and an inability to meet the increasingly diverse needs of customers.

[0108] 2) Architecture 2: Low-voltage battery + hybrid inverter, such as Figure 9 As shown, however, this architecture only supports low-voltage battery systems and cannot use high-voltage battery systems. At the same time, the bidirectional two-stage DC-DC hybrid inverter is bulky and heavy, which cannot meet the needs of one person to install it independently, and the cost is high.

[0109] 3) Architecture 3: Pseudo-high voltage battery + hybrid inverter, such as Figure 10 As shown, although the architecture can support both high-voltage and low-voltage battery systems, the pseudo-high-voltage battery technology with an integrated boost module is technically challenging and has a long development cycle.

[0110] 4) Architecture 4: Pseudo-high voltage battery + single-stage DC-DC converter + inverter, such as Figure 11 As shown, although the architecture can support both high-voltage and low-voltage battery systems, the technology of pseudo-high-voltage batteries with internally integrated boost modules is difficult and has a long development cycle.

[0111] To address the aforementioned technical issues, this application proposes an energy storage system. The hybrid inverter in this system can be adapted to both low-voltage and high-voltage battery systems. When using a high-voltage battery system, the high-voltage battery can be directly connected to the hybrid inverter. When using a low-voltage battery system, the low-voltage battery is first connected to the first DC-DC converter module in the low-voltage battery system before being connected to the hybrid inverter. The first DC-DC converter module has low technical difficulty and a short development cycle, reducing application costs. Furthermore, when the low-voltage battery system meets preset startup conditions, the controller controls the second DC-DC converter module to start and sends a fast-start command to the first DC-DC converter module via a hard-wired signal. This allows the first and second DC-DC converter modules to start synchronously based on the fast-start command, improving the discharge response speed of the low-voltage battery system to quickly support the DC bus energy demand and ensure stable operation of the energy storage system.

[0112] like Figure 12 and 13 As shown, the energy storage system of this embodiment includes: a low-voltage battery system 20 or a high-voltage battery system 30. The low-voltage battery system 20 includes a low-voltage battery 21 and a first DC-DC module 22 connected to the low-voltage battery 21. The high-voltage battery system 30 includes a high-voltage battery 41. A hybrid inverter 10 includes a second DC-DC module 11 connected to a DC bus and a controller 14. The second DC-DC module 11 is also adapted to connect to the first DC-DC module 22 or the high-voltage battery 41, and the second DC-DC module 11 is also adapted to communicate with the first DC-DC module 22 via a hard-wired signal. The controller 14 is used to control the second DC-DC module 11 to start when the low-voltage battery system 20 meets preset start-up conditions, and to send a fast start command to the first DC-DC module 22 via a hard-wired signal so that the first DC-DC module 22 starts synchronously with the second DC-DC module 11 based on the fast start command.

[0113] Specifically, taking a photovoltaic energy storage system as an example, the DC side of the hybrid inverter 10 is connected to the photovoltaic modules and the battery system, while the AC side of the hybrid inverter 10 is connected to the load and the AC power grid (i.e., external power source). Both the photovoltaic modules and the battery system are connected to the DC bus of the hybrid inverter 10. It can be understood that the battery system can output electrical energy to power the load connected to the hybrid inverter 10, and the AC power grid connected to the hybrid inverter 10, i.e., the external power source, can also charge the battery system.

[0114] The hybrid inverter 10 can be connected to either a high-voltage battery system or a low-voltage battery system, and includes a second DC-DC module 11, a controller 14, a sampling module, etc. When the hybrid inverter 10 is connected to the low-voltage battery system 20, such as... Figure 12As shown, the low-voltage battery 21 in the low-voltage battery system 20 is first connected to the first DC-DC module 22, and then the first DC-DC module 22 is connected to the second DC-DC module 11 to complete the connection between the low-voltage battery system 20 and the hybrid inverter 10. When both the first DC-DC module 22 and the second DC-DC module 11 are in the startup state, the energy in the low-voltage battery 20 can be output to the DC bus. The low-voltage battery system 20 and the hybrid inverter 10 have power interfaces, communication interfaces, and hardware signal interfaces. That is, the second DC-DC module 11 can be connected to the first DC-DC module 22 through the power interface, communication interface, and hardware signal interface. Besides communicating with the first DC-DC module 22 via the communication interface, the second DC-DC module 11 can also communicate quickly via hardware signals through the hardware signal interface. The specific communication division can be determined according to the situation. The application technology of the first DC-DC module 22 in this low-voltage battery system 20 is low, the development cycle is short, and the application cost is reduced.

[0115] When the hybrid inverter 10 is connected to the high-voltage battery system 40, such as Figure 13 As shown, the high-voltage battery 41 is directly connected to the second DC-DC module 11. When the second DC-DC module 11 is in the start-up state, it can output the power in the high-voltage battery 41 to the DC bus. The high-voltage battery 41 has a power interface and a communication interface with the hybrid inverter 10. The second DC-DC module 11 can communicate with the first DC-DC module 22 through the communication interface.

[0116] In addition, when the hybrid inverter 10 is connected to the low-voltage battery system 20 and the hybrid inverter 10 is supplying power to the load, if the output energy of the photovoltaic module is sufficient to support the output energy demand of the hybrid inverter, the second DC-DC module 11 and the first DC-DC module 22 are controlled to enter the standby state to save the energy consumption of the low-voltage battery 21.

[0117] When the output energy of the photovoltaic modules cannot support the output energy demand of the hybrid inverter at a certain moment, such as when a large load is suddenly connected to the AC side of the energy storage inverter and the total load after connection is greater than the total power generation of the photovoltaic modules, the low-voltage battery system 20 needs to supplement the DC bus of the hybrid inverter to prevent the entire energy storage system from collapsing. At this time, it is determined that the low-voltage battery system meets the preset start-up conditions, and the controller of the hybrid inverter controls the second DC-DC module 11 to start. At the same time, it sends a fast start command to the first DC-DC module 22 based on the hardware signal interface, so that the first DC-DC module 22 starts synchronously with the second DC-DC module 11 based on the fast start command. Thus, the low-voltage battery 21 quickly starts to output energy based on the started first DC-DC module 22 and second DC-DC module 11 to supplement the DC bus of the hybrid inverter 10. At this time, power is supplied by both the photovoltaic modules and the low-voltage battery.

[0118] The hardware signal interface is an I / O interface, and the hardware signal is a high-level signal or a low-level signal. For example, when the hardware signal is a high-level signal, it is a fast start instruction; when the hardware signal is a low-level signal, it is a standby instruction. So, the first DC-DC module 22 performs fast start when it receives a high-level signal, and stops working when it receives a low-level signal.

[0119] It should be further noted that the DC-DC module in this application can be a DC-DC converter such as LLC, DAB, BUCK, or BOOST, and the hardware signal can be in the form of dry contact, level signal conversion, level toggling, button, etc., without any specific limitations.

[0120] Combination Figure 3 and Figure 4 As shown, according to an embodiment of the present invention, the hybrid inverter 10 further includes a DCAC module 12, the DC side of the DCAC module 12 being connected to a DC bus, and the AC side of the DCAC module 12 being adapted to connect to a load. The controller 14 is further configured to: acquire the DC bus voltage of the DC bus and acquire the voltage difference between the DC bus reference voltage and the DC bus voltage during the process of controlling the DCAC module 12 to operate and supply power to the load; and determine that the low-voltage battery system meets the preset start-up conditions when the voltage difference is greater than a first preset voltage difference.

[0121] Specifically, with Figure 3 Taking the photovoltaic energy storage system shown as an example, the new energy power generation device 30 is a photovoltaic module. Both the new energy power generation device 30 and the low-voltage battery system 20 are connected to the DC bus of the hybrid inverter 10. When the DCAC module 12 supplies power to the load, the DCAC module 12 directly draws DC power from the DC bus and converts the DC power into AC power before outputting it to supply power to the load. The DC bus serves as the energy aggregation channel for the new energy power generation device 30 and the low-voltage battery system 20.

[0122] The controller 14 determines whether the low-voltage battery system meets the preset start-up conditions based on the voltage difference between the DC bus reference voltage and the DC bus voltage, and the magnitude of this difference compared to a first preset voltage difference.

[0123] According to an embodiment of the present invention, the controller 14 is further configured to: after the first DC-DC module 22 and the second DC-DC module 11 are started synchronously, determine the load demand power of the load, obtain the product of the load demand power, the voltage difference and the preset voltage-power conversion coefficient to obtain the first power, and obtain the sum of the first power and the preset power margin to obtain the output power of the second DC-DC module 11.

[0124] According to an embodiment of the present invention, the controller 14 is further configured to: after the first DC-DC module 22 and the second DC-DC module 11 are started synchronously, acquire the absolute value of the voltage difference between the DC bus reference voltage and the DC bus voltage, and control the second DC-DC module 11 and the first DC-DC module 22 to maintain the current working state when the absolute value of the voltage difference is less than a second preset voltage difference.

[0125] According to one embodiment of the present invention, the hybrid inverter 10 further includes a third DC-DC module 13, one end of which is connected to the DC bus, and the other end of which is adapted to connect to the new energy power generation device 30. The controller 14 is also used to control the operation of the third DC-DC module 13 so that the new energy power generation device 30 supplies power to the load through the third DC-DC module 13 and the DC-AC module 12.

[0126] It should be noted that, in addition to supplying power to the load through the third DC-DC module 13 and the DC-AC module 12, the new energy power generation device 30 can also charge the high-voltage battery 41 through the third DC-DC module 13 and the second DC-DC module 11, or charge the low-voltage battery 21 through the third DC-DC module 13, the second DC-DC module 11 and the first DC-DC module 22.

[0127] According to one embodiment of the present invention, the controller 14 is further configured to: respond to the access signal of the target battery system and send an identification information acquisition instruction to the target battery system; wherein the target battery system is a low-voltage battery system 20 or a high-voltage battery system 40; respond to the response instruction with identification information sent by the target battery system, acquire the identification information, and acquire a control program corresponding to the target battery system based on the identification information; and control the target battery system based on the control program.

[0128] Specifically, in the case where the energy storage system includes a low-voltage battery system 20, such as Figure 14 As shown, COM is the communication connection line, Poer is the power connection line, the hardware signal is the hardware level signal, and the button signal is the voltage signal triggered by the control button. The control button is set to the first DC-DC module 22. When the operator controls the control button to operate, the button signal triggered by the control button is simultaneously sent to the first DC-DC module 22, the hybrid inverter, and the low-voltage battery 21.

[0129] In the case where the energy storage system includes a high-voltage battery system 40, such as Figure 15 As shown, COM is the communication connection line, Poer is the power connection line, and the button signal is the voltage signal triggered by the control button. The control button is set to the high-voltage battery 41. When the operator controls the control button to operate, the button signal is sent to both the high-voltage battery 41 and the hybrid inverter.

[0130] The button signal can be used to power on and off the battery system.

[0131] Taking the energy storage system including the low-voltage battery system 20 as an example, the function of the button signal is as follows:

[0132] ① The low-voltage battery system (first DC-DC module 22, low-voltage battery 21 and second DC-DC module 11) is powered off via button signal;

[0133] ② The low-voltage battery system (first DC-DC module 22, low-voltage battery 21 and second DC-DC module 11) is powered on via button signal;

[0134] Under normal circumstances, after connecting the low-voltage battery system and the hybrid inverter, staff can control the energy storage system via a mobile app through the established communication network to perform functions such as starting and stopping. This can be achieved by sending corresponding control signals to the hybrid inverter or sending corresponding control signals to both the hybrid inverter and the battery system. However, when the network infrastructure is disrupted due to force majeure (such as war, weather, geological disasters, etc.), staff cannot control the energy storage system via mobile phone. In this case, button signals serve as manual control signals, providing a reliable emergency response.

[0135] For example, in an energy storage system equipped with a low-voltage battery system 20, when the low-voltage battery 21 is depleted (out of power) and shut down, and the first DC-DC module 22 and the second DC-DC module 11 are also off, if it is necessary to start the first DC-DC module 22 and the second DC-DC module 11 to charge the low-voltage battery 21, the second DC-DC module 22 and the first DC-DC module 11 can be started by a button signal, and the low-voltage battery 21 can be charged by AC power provided by the AC grid or by the power provided by the new energy power generation device 30. When the low-voltage battery 21 is fully charged but is off, if there is a power outage in the AC grid at night or on a cloudy day when there is insufficient sunlight, and the battery energy is needed for power supply, the low-voltage battery 21 and the first DC-DC module 22 and the second DC-DC module 11 can be activated by a manual button signal to supply power to the user side.

[0136] Combination Figure 14 and Figure 15 As shown, according to one embodiment of the present invention, the hybrid inverter 10 includes multiple DCAC modules 12 connected in parallel on their AC sides to realize the function of parallel expansion of the hybrid inverter 10, thereby increasing the grid-connected power and meeting different load requirements. It should be noted that COM is a communication signal.

[0137] Therefore, this embodiment, based on the traditional hybrid inverter solution and considering requirements such as development cycle, cost, installability, and compatibility, proposes an innovative energy storage system technology solution, with the following specific advantages:

[0138] 1. The same hybrid inverter 10 can achieve compatibility and adaptation between high-voltage battery system 30 and low-voltage battery system 20, and can perform adaptive matching of high and low voltage battery systems during installation.

[0139] 2. Reduce the number of product codes, significantly lowering production, warehousing, transportation, installation, and maintenance costs;

[0140] 3. The development technology is simple and the development cycle is short, which meets the needs of the current highly competitive energy storage market;

[0141] 4. The overall cost of the solution is low, enhancing competitiveness;

[0142] 5. It relies on hardware level signals to achieve synchronous and rapid startup of the second DC-DC module and the first DC-DC module, has the function of dynamic switching under heavy load, and has a fast response speed.

[0143] It should be noted that for details not disclosed in the energy storage system of the present invention embodiments, please refer to the details disclosed in the control method of the hybrid inverter of the above embodiments of the present invention, which will not be repeated here.

[0144] According to an embodiment of the energy storage system of the present invention, when the energy storage system includes a low-voltage battery system, the low-voltage battery system includes a low-voltage battery and a first DC-DC converter module connected to the low-voltage battery. The hybrid inverter includes a second DC-DC converter module connected to the DC bus and a controller. The second DC-DC converter module is also adapted to connect to the first DC-DC converter module and is also adapted to communicate with the first DC-DC converter module via a hard-wired signal. When the low-voltage battery system meets preset startup conditions, the controller controls the second DC-DC converter module to start and sends a fast startup command to the first DC-DC converter module via a hard-wired signal, so that the first DC-DC converter module starts synchronously with the second DC-DC converter module based on the fast startup command. When the energy storage battery includes a high-voltage battery system, the high-voltage battery system includes a high-voltage battery, and the second DC-DC converter module connected to the DC bus in the hybrid inverter is also adapted to connect to the high-voltage battery. Thus, the energy storage system can realize the synchronous startup of the first DC-DC converter module of the low-voltage battery system and the second DC-DC converter module of the hybrid inverter, improve the discharge response speed of the low-voltage battery system, quickly support the energy demand of the DC bus, and enable the energy storage system to operate stably.

[0145] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0146] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0147] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0148] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0149] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0150] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A control method for a hybrid inverter, characterized in that, The hybrid inverter is adapted to connect to a low-voltage battery system, the low-voltage battery system including a low-voltage battery and a first DC-DC module connected to the low-voltage battery, the hybrid inverter including a second DC-DC module connected to a DC bus, the second DC-DC module being adapted to connect to the first DC-DC module, and the second DC-DC module being further adapted to communicate with the first DC-DC module via a hardwired signal, the method comprising: When the low-voltage battery system meets the preset startup conditions, the second DC-DC module is controlled to start, and a fast startup command is sent to the first DC-DC module through the hard-wired signal, so that the first DC-DC module starts synchronously with the second DC-DC module based on the fast startup command.

2. The method according to claim 1, characterized in that, The hybrid inverter also includes a DCAC module, the DC side of which is connected to the DC bus, and the AC side of which is adapted to connect to a load. The low-voltage battery system is determined to meet preset startup conditions through the following methods: During the process of controlling the DCAC module to operate and supply power to the load, the DC bus voltage of the DC bus is acquired. Obtain the voltage difference between the DC bus reference voltage and the DC bus voltage; If the voltage difference is greater than the first preset voltage difference, the low-voltage battery system is determined to meet the preset startup conditions.

3. The method according to claim 2, characterized in that, After the first DC-DC module and the second DC-DC module are started synchronously, the method further includes: Determine the load power requirement of the load; The first power is obtained by multiplying the load demand power, the voltage difference, and the preset voltage-power conversion coefficient, and the output power of the second DC-DC module is obtained by summing the first power and the preset power margin.

4. The method according to claim 2, characterized in that, After the first DC-DC module and the second DC-DC module are started synchronously, the method further includes: Obtain the absolute value of the voltage difference between the DC bus reference voltage and the DC bus voltage; When the absolute value of the voltage difference is less than the second preset voltage difference, the second DC-DC module and the first DC-DC module are controlled to maintain their current working state.

5. The method according to claim 2, characterized in that, The hybrid inverter further includes a third DC-DC module, one end of which is connected to the DC bus, and the other end of which is adapted to connect to a new energy power generation device. The method further includes: The third DC-DC module is controlled to operate so that the new energy power generation device supplies power to the load through the third DC-DC module and the DC-AC module.

6. The method according to claim 1, characterized in that, The hybrid inverter is also adapted to be connected to a high-voltage battery system, the high-voltage battery system including a high-voltage battery, and the second DC-DC module is also adapted to be connected to the high-voltage battery. The method further includes: In response to the access signal of the target battery system, an identification information acquisition instruction is sent to the target battery system; wherein, the target battery system is the low-voltage battery system or the high-voltage battery system; In response to a response command with identification information sent by the target battery system, the identification information is obtained, and a control program corresponding to the target battery system is obtained based on the identification information; The target battery system is controlled based on the control program.

7. A controller, characterized in that, The system includes a memory, a processor, and a control program for a hybrid inverter stored in the memory and executable on the processor. When the processor executes the control program for the hybrid inverter, it implements the control method for the hybrid inverter according to any one of claims 1-6.

8. An energy storage system, characterized in that, include: A low-voltage battery system or a high-voltage battery system, wherein the low-voltage battery system includes a low-voltage battery and a first DC-DC module connected to the low-voltage battery, and the high-voltage battery system includes a high-voltage battery; A hybrid inverter, the hybrid inverter including a second DC-DC module connected to a DC bus and a controller, the second DC-DC module being adapted to connect to the first DC-DC module or the high-voltage battery, and the second DC-DC module being adapted to communicate with the first DC-DC module via a hard-wired signal; The controller is used to control the second DC-DC module to start when the low-voltage battery system meets the preset start-up conditions, and to send a fast start command to the first DC-DC module through the hard-wired signal so that the first DC-DC module starts up synchronously with the second DC-DC module based on the fast start command.

9. The system according to claim 8, characterized in that, The hybrid inverter also includes a DCAC module, the DC side of which is connected to the DC bus, and the AC side of which is adapted to connect to a load. The controller is further configured to: acquire the DC bus voltage of the DC bus and acquire the voltage difference between the DC bus reference voltage and the DC bus voltage during the process of controlling the DCAC module to operate and supply power to the load; and determine that the low-voltage battery system meets the preset start-up conditions if the voltage difference is greater than a first preset voltage difference.

10. The system according to claim 9, characterized in that, The controller is further configured to: after the first DCDC module and the second DCDC module are started synchronously, determine the load power demand of the load, obtain the product of the load power demand, the voltage difference and the preset voltage-power conversion coefficient to obtain the first power, and obtain the sum of the first power and the preset power margin to obtain the output power of the second DCDC module.

11. The system according to claim 9, characterized in that, The controller is further configured to: after the first DCDC module and the second DCDC module are started synchronously, obtain the absolute value of the voltage difference between the DC bus reference voltage and the DC bus voltage, and control the second DCDC module and the first DCDC module to maintain the current working state when the absolute value of the voltage difference is less than a second preset voltage difference.

12. The system according to claim 9, characterized in that, The hybrid inverter also includes a third DC-DC module, one end of which is connected to the DC bus, and the other end of which is adapted to connect to a new energy power generation device. The controller is also used to control the operation of the third DC-DC module so that the new energy power generation device supplies power to the load through the third DC-DC module and the DC-AC module.

13. The system according to claim 9, characterized in that, The controller is also used for: In response to the access signal of the target battery system, an identification information acquisition instruction is sent to the target battery system; wherein, the target battery system is the low-voltage battery system or the high-voltage battery system; In response to a response command with identification information sent by the target battery system, the identification information is obtained, and a control program corresponding to the target battery system is obtained based on the identification information; The target battery system is controlled based on the control program.

14. The system according to claim 9, characterized in that, The hybrid inverter comprises multiple inverters, and the AC side of the DCAC modules of the multiple hybrid inverters are connected in parallel.

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