Household photovoltaic energy storage inverter, system and control method

Abstract

The invention discloses a household photovoltaic energy storage inverter, a system and a control method. The household photovoltaic energy storage inverter comprises an inversion output switch, the first end of which is connected to the AC output end of the inversion module so as to switch the output state of the inversion module; the power supply port is used for being connected with an important load of a user, and the power supply port is connected to the second end of the inversion output switch so as to supply power to the power supply port; the oil engine port can be connected with a fuel oil generator; the oil engine port switch is connected between the power supply port and the oil engine port; the household photovoltaic energy storage inverter has an oil engine operation mode, in the oil engine operation mode, the inverter output switch is kept closed, and when the oil engine port switch is switched off, the inverter module is configured to convert electric power from a photovoltaic panel and / or a battery and then supply the electric power to the important load or supply the electric power to the important load by a power grid; and when the oil engine port switch is closed, the fuel generator supplies power to the important load.

Description

Technical Field

[0001] The present invention relates to a household photovoltaic energy storage inverter, a system and a control method. Background Art

[0002] With the maturity of photovoltaic energy storage technologies and the continued reduction in system costs, the installation of household photovoltaic energy storage systems is growing rapidly, and differentiated demands are constantly emerging. Because photovoltaic power generation depends on weather and light conditions, and the capacity of energy storage batteries is objectively limited, the continuous power supply reliability of photovoltaic energy storage systems is limited in areas where there is no power grid or the power grid is unreliable. The existing solution is to use diesel generators as a backup power source, using diesel generators to power users' critical loads in the event of power grid loss and the photovoltaic energy storage system being unable to supply power. Existing solutions typically use an external transfer switch (ATS) to switch the load from the photovoltaic energy storage system to the diesel generator when the diesel generator is needed. The disadvantage of this solution is that it requires an additional transfer switch, and the additional ATS automatic switching solution increases the cost and complexity of the system; manual switching cannot guarantee continuous and reliable power supply to critical loads.

[0003] The above information disclosed in this Background section is only for enhancement of understanding of the background of the application and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the Invention

[0004] The present invention proposes a household photovoltaic energy storage inverter, system, and control method, which can ensure that the user's important loads (typically such as lighting and refrigerators) are not interrupted and can continue to operate; moreover, the circuit and control circuit of the photovoltaic energy storage inverter of this application are used to realize the automatic connection and disconnection of the fuel generator.

[0005] A first aspect of the present invention provides a household photovoltaic energy storage inverter, wherein the inverter has a DC port for connecting a photovoltaic panel and a battery, and the household photovoltaic energy storage inverter includes:

[0006] an inverter output switch, a first end of which is connected to the AC output end of the inverter module to switch the output state of the inverter module;

[0007] A power supply port, which is used to connect an important load of a user, and the power supply port is connected to the second end of the inverter output switch to supply power to the power supply port;

[0008] The diesel generator port can be connected to a fuel generator, smart load, or photovoltaic grid-connected inverter;

[0009] an oil engine port switch, connected between the power supply port and the oil engine port;

[0010] In which, the household photovoltaic energy storage inverter has an oil engine operation mode. In the oil engine operation mode, the inverter output switch remains closed. When the oil engine port switch is disconnected, the inverter module is configured to convert the power from the photovoltaic panel and / or battery to supply power to the important load or to supply power to the important load from the power grid; when the oil engine port switch is closed, the fuel generator supplies power to the important load.

[0011] Furthermore, the household photovoltaic energy storage inverter includes a PV module, a battery and an inverter module. The PV module converts PV (photovoltaic panel) into the required DC voltage, and the battery converts PV and battery voltage into the required DC voltage; the inverter module converts the DC voltage into an AC voltage that can be used by the device.

[0012] In a preferred embodiment, the household photovoltaic energy storage inverter further includes:

[0013] A grid port, which is used to connect to a grid;

[0014] a grid port switch connected between the inverter output switch and the grid port;

[0015] The PV module can transmit power from the PV panels to the DC bus. The battery module is a bidirectional module, releasing battery power to the inverter DC bus circuit and also charging the battery from the DC bus circuit. The inverter module is also a bidirectional conversion module, which can output energy from the DC bus to the AC side and input energy from the AC side to the DC bus circuit.

[0016] In the oil engine operation mode, the household photovoltaic energy storage inverter has a grid-connected working state, an off-grid working state and an oil engine-connected working state. In the grid-connected working state, the inverter output switch and the grid port switch are closed, the oil engine port switch is disconnected, and the inverter and the grid supply power to the important load; in the off-grid working state, the inverter output switch is closed, the oil engine port switch and the grid port switch are disconnected, and the inverter module converts the power from the photovoltaic panel and / or the battery to supply power to the important load; in the oil engine-connected working state, the inverter output switch and the oil engine port switch are closed, the grid port switch is disconnected, and the fuel generator supplies power to the important load and can also charge the battery.

[0017] In a more preferred embodiment, the output side of the inverter module has a first power line, the power supply port is connected to the first power line through a second power line, and the diesel generator port is connected to the first power line through a third power line. When the household photovoltaic energy storage inverter is in the diesel generator parallel working state, the diesel generator port and the power supply port are connected through the third power line, the first power line and the second power line to transmit power from the fuel generator to important loads.

[0018] In a preferred embodiment, the household photovoltaic energy storage inverter also has a smart load operation mode. In the smart load operation mode, the oil engine port is connected to a smart load. When the oil engine port switch is closed, the inverter module is configured to convert the power from the photovoltaic panel and / or battery to power the important load and the smart load, or to power the important load and the smart load from the power grid; when the oil engine port switch is disconnected, the inverter module stops supplying power to the smart load.

[0019] In a more preferred embodiment, the generator port switch is allowed to close when the inverter module is connected to the grid; when the actual battery SOC value exceeds a preset SOC value; or when the PV power output is high enough to feed excess power into the grid. The generator port mode and the conditions for connecting / disconnecting smart loads are user-configurable.

[0020] In a more preferred embodiment, the output side of the inverter module has a first power line, the power supply port is connected to the first power line through a second power line, and the diesel engine port is connected to the first power line through a third power line. In the smart load operation mode, the household photovoltaic energy storage inverter connects the inverter module and the diesel engine port through the third power line and the first power line to supply power to the smart load.

[0021] In a preferred embodiment, the household photovoltaic energy storage inverter also has a photovoltaic grid-connected inverter mode. In the photovoltaic grid-connected inverter mode, the diesel engine port is configured to be connected to a photovoltaic grid-connected inverter. When the diesel engine port switch is closed, the inverter module is configured to convert the power from the photovoltaic grid-connected inverter to power the important load or charge the battery, and can transmit excess power to the power grid.

[0022] In a more preferred embodiment, in the photovoltaic grid-connected inverter mode, when the household photovoltaic energy storage inverter is grid-connected and the diesel engine port switch is closed, if the grid is abnormal, the diesel engine port switch is opened, and after the household photovoltaic energy storage inverter switches to off-grid operation, the diesel engine port switch is closed;

[0023] If the household photovoltaic energy storage inverter switches from off-grid operation to grid-connected operation, the oil engine port switch is disconnected. After the household photovoltaic energy storage inverter is grid-connected, the oil engine port switch is closed.

[0024] When the diesel generator port is disconnected, the PV grid-connected inverter will cease operation. When the diesel generator port is closed, the PV grid-connected inverter will be integrated into the system. In the on-grid operating condition, the PV energy storage inverter will, in the off-grid operating condition, have its underlying EMS (Energy Management System) module calculate the system's required power. It then regulates the power of the PV grid-connected inverter connected to the diesel generator port by adjusting its own output voltage and frequency, while also controlling battery charging and discharging.

[0025] In a more preferred embodiment, the output side of the inverter module has a first power line, the power supply port is connected to the first power line through a second power line, and the diesel engine port is connected to the first power line through a third power line. When the household photovoltaic energy storage inverter is in photovoltaic grid-connected inverter mode, the diesel engine port and the power supply port are connected through the third power line, the first power line and the second power line to transmit power from the photovoltaic grid-connected inverter to important loads.

[0026] In a preferred embodiment, the inverter output switch includes a relay group, the oil engine port switch includes a relay group, and the grid port switch includes multiple relay groups cascaded with each other;

[0027] The household photovoltaic energy storage inverter further includes a GFCI module connected to the AC output side of the inverter module, and the inverter output switch is provided on the output side of the GFCI module;

[0028] The household photovoltaic energy storage inverter further includes a sampling module for collecting the AC output voltage and current of the inverter module, the voltage and current of the power supply port, and the voltage and current of the oil generator port.

[0029] A second aspect of the present invention provides a household photovoltaic energy storage system, which includes a user's important load, a fuel generator and the household photovoltaic energy storage inverter, wherein the important load is connected to the power supply port of the household photovoltaic energy storage inverter, and the oil generator is connected to the oil generator port of the household photovoltaic energy storage inverter.

[0030] A third aspect of the present invention provides a household photovoltaic energy storage system, which includes a user's important load, a smart load and the household photovoltaic energy storage inverter, wherein the important load is connected to the power supply port of the household photovoltaic energy storage inverter, and the smart load is connected to the oil generator port of the household photovoltaic energy storage inverter.

[0031] A fourth aspect of the present invention provides a household photovoltaic energy storage system, which includes a user's important load, a photovoltaic grid-connected inverter and the household photovoltaic energy storage inverter, wherein the important load is connected to the power supply port of the household photovoltaic energy storage inverter, and the photovoltaic grid-connected inverter is connected to the oil engine port of the household photovoltaic energy storage inverter.

[0032] According to a specific and preferred embodiment of the present invention, a household photovoltaic energy storage system includes a household photovoltaic energy storage inverter, wherein the household photovoltaic energy storage inverter includes:

[0033] PV modules, which deliver PV power to the inverter DC bus circuit;

[0034] The battery module connects the battery and the inverter DC bus to achieve power interaction between the battery and DC bus circuits;

[0035] The inverter module realizes the power interaction between the DC bus circuit and the AC measurement.

[0036] an inverter output switch, a first end of which is connected to the AC output end of the inverter module to switch the output state of the inverter module;

[0037] PV port, connecting PV panels and inverter PV modules;

[0038] Battery port, connecting the battery and inverter battery module;

[0039] A power supply port (important load port), which is used to connect the user's important load, and the power supply port is connected to the AC output end of the inverter module to supply power to the power supply port;

[0040] Oil generator port, which can be connected to a fuel generator;

[0041] an oil engine port switch, connected between the power supply port and the oil engine port;

[0042] The household photovoltaic energy storage inverter has an oil engine operation mode, a smart load mode and a photovoltaic grid-connected inverter mode;

[0043] When the household photovoltaic energy storage inverter is in the diesel engine operation mode, the diesel engine port is connected to the fuel engine, so that when the diesel engine port switch is disconnected, the inverter module is configured to convert the power from the photovoltaic panel and / or battery to supply power to the important load or to supply power to the important load from the grid; when the diesel engine port switch is closed, the fuel generator supplies power to the important load;

[0044] When the household photovoltaic energy storage inverter is in the smart load operation mode, the diesel generator port is connected to a smart load, so that when the diesel generator port switch is closed, the inverter module is configured to convert the power from the photovoltaic panel and / or battery to supply power to the important load and the smart load, or to supply power to the important load and the smart load from the power grid; when the diesel generator port switch is opened, the inverter module stops supplying power to the smart load;

[0045] When the household photovoltaic energy storage inverter is in the photovoltaic grid-connected inverter mode, the diesel engine port is connected to a photovoltaic grid-connected inverter. When the diesel engine port switch is closed, the inverter module is configured to convert the power from the photovoltaic grid-connected inverter to power the important load or charge the battery.

[0046] A fifth aspect of the present invention provides a control method for the household photovoltaic energy storage inverter, the control method comprising the following steps of paralleling the oil generator:

[0047] The household photovoltaic energy storage inverter is placed in an oil engine operation mode, and the power supply port of the household photovoltaic energy storage inverter is connected to the user's important load;

[0048] Real-time detection of the operating status of the household photovoltaic energy storage inverter. When the set diesel generator start-up conditions are met, the household photovoltaic energy storage inverter sends a start-up signal to the diesel generator to start the diesel generator;

[0049] Controlling the AC output voltage of the household photovoltaic energy storage inverter to follow the voltage of the fuel generator, and after reaching the same frequency and phase as the voltage of the fuel generator, closing the oil generator port switch, so that the fuel generator supplies power to the important load;

[0050] If there is a power grid, the control method further includes:

[0051] Grid-connected switching step: closing the grid port switch between the inverter module of the household photovoltaic energy storage inverter and the grid port, closing the inverter output switch of the inverter module of the household photovoltaic energy storage inverter, and opening the diesel engine port switch, so that the inverter module is connected to the grid;

[0052] Off-grid switching step: closing the grid port switch between the inverter module of the household photovoltaic energy storage inverter and the grid port, closing the inverter output switch of the inverter module of the household photovoltaic energy storage inverter, and opening the diesel engine port switch, so that the inverter module is disconnected from the grid;

[0053] Wherein, in the oil-generating unit paralleling step, the inverter output switch of the inverter module of the household photovoltaic energy storage inverter is kept closed;

[0054] The important load is continuously powered by electricity from photovoltaic panels and / or batteries converted by an inverter module, electricity from a power grid, or electricity from the fuel generator.

[0055] A sixth aspect of the present invention provides a control method for the household photovoltaic energy storage inverter, the control method comprising:

[0056] The household photovoltaic energy storage inverter is placed in a smart load operation mode, and the power supply of the household photovoltaic energy storage inverter is disconnected from the important load of the user;

[0057] After detecting that the household photovoltaic energy storage inverter meets the conditions for connecting to a smart load, the oil generator port switch is closed to connect to the smart load;

[0058] After detecting that the household photovoltaic energy storage inverter does not meet the conditions for disconnecting the smart load, the oil engine port switch is turned off to disconnect the smart load;

[0059] The conditions for connecting the smart load include: the actual SOC value of the battery is greater than the preset SOC value, or the inverter module is connected to the grid; or the PV generates a lot of power and there is excess power to feed into the grid.

[0060] The conditions for disconnecting the smart load include: the oil generator port disconnecting the enable signal, or the actual SOC value of the battery is not greater than the preset SOC value; or the power generated by the PV decreases so that there is no excess energy, and the system starts to buy electricity from the grid;

[0061] The switching-on or switching-off conditions of the intelligent load are configured by the user according to the needs;

[0062] The important loads are continuously powered by electricity from photovoltaic panels and / or batteries converted by the inverter module or by electricity from the power grid.

[0063] A seventh aspect of the present invention provides a method for controlling a household photovoltaic energy storage inverter, comprising the following photovoltaic grid-connected inverter access steps:

[0064] The household photovoltaic energy storage inverter is placed in a photovoltaic grid-connected inverter mode, with the power supply port of the household photovoltaic energy storage inverter connected to the user's important load, and the diesel generator port of the household photovoltaic energy storage inverter connected to the photovoltaic grid-connected inverter, so that the power from the photovoltaic grid-connected inverter is used to power the important load or charge the battery;

[0065] The important load is continuously powered by electricity from photovoltaic panels and / or batteries converted by an inverter module, electricity from a power grid, or electricity from the photovoltaic grid-connected inverter.

[0066] In a preferred embodiment, the household photovoltaic energy storage inverter is capable of exchanging information with the photovoltaic grid-connected inverter via a communication line. The household photovoltaic energy storage inverter transmits acquired grid and current information to the photovoltaic grid-connected inverter for reverse flow control. It should be noted that communication between the photovoltaic energy storage inverter and the photovoltaic grid-connected inverter is not required for the system, but is a measure to optimize system performance. In the absence of communication, the energy storage inverter can control the power production of the entire system by adjusting its own output power and output voltage.

[0067] In a preferred embodiment, when there is a grid, after closing the grid port switch between the inverter module and the grid port of the household photovoltaic energy storage inverter, the diesel engine port switch is closed to make the grid voltage reach the photovoltaic grid-connected inverter.

[0068] In a preferred embodiment, during grid-connected operation, if a grid abnormality occurs, the grid port switch and the diesel engine port switch are disconnected; after the user's photovoltaic energy storage inverter switches to off-grid operation and the operation is stable, the diesel engine port switch is closed.

[0069] In a preferred embodiment, during off-grid startup, after the household photovoltaic energy storage inverter is stably operating off-grid, the diesel engine port is closed, so that the output voltage of the household photovoltaic energy storage inverter reaches that of the photovoltaic grid-connected inverter.

[0070] In a preferred embodiment, during off-grid operation, if the output power of the photovoltaic grid-connected inverter is less than the power of the important load, the household photovoltaic energy storage inverter supplies power to the important load; if the output power of the photovoltaic grid-connected inverter is greater than the power of the important load, the photovoltaic grid-connected inverter supplies power to the important load, and the household photovoltaic energy storage inverter allocates excess power from the photovoltaic grid-connected inverter to charge the battery.

[0071] In one embodiment, the photovoltaic energy storage inverter can adjust the output power of the photovoltaic grid-connected inverter according to the power required by the load and the battery. This adjustment is achieved by controlling the output voltage / frequency of the photovoltaic energy storage inverter.

[0072] The inverter integrates an EMS control function, which controls battery charging or discharging according to system requirements to achieve maximum system production efficiency. It also outputs commands to adjust the output voltage / frequency of the energy storage inverter to adjust the output power of the photovoltaic grid-connected inverter.

[0073] The above solution adopted by the present invention has the following advantages:

[0074] The household photovoltaic energy storage inverter of the present invention can ensure that the user's important loads (typically refrigerators and lighting) are not interrupted and can operate continuously. Moreover, the circuit and control circuit of the photovoltaic energy storage inverter of this application are used to realize the automatic connection and disconnection of the fuel generator, eliminating the need for an additional switching device. When the system needs to use the oil generator, the household photovoltaic energy storage inverter can control the start-up of the fuel generator to power the important loads. It has the advantages of high system integration, automation without human intervention, high reliability of continuous power supply of the system, and good economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0076] Figure 1 4 is a topological diagram of a photovoltaic energy storage system according to an embodiment of the present invention.

[0077] Figure 2 The topology diagram of a household photovoltaic energy storage inverter in a diesel engine operation mode according to an embodiment of the present invention is shown in FIG.

[0078] Figure 3 The figure is a block diagram of AC side switching control when a household photovoltaic energy storage inverter is in a diesel engine operation mode according to an embodiment of the present invention.

[0079] Figure 4 The figure is a block diagram of AC side switching control of a household photovoltaic energy storage inverter in a smart load operation mode according to an embodiment of the present invention.

[0080] Figure 5 The figure is a block diagram of AC side switching control of a household photovoltaic energy storage inverter in photovoltaic grid-connected inverter mode according to an embodiment of the present invention.

[0081] Among them: 100, household photovoltaic energy storage inverter; 110, inverter module; 120, battery; 130, GFCI module; 140, EMC module; 150, inverter output switch; 160, grid port switch; 170, diesel port switch; 181, first power line; 182, second power line; 183, third power line;

[0082] 200, photovoltaic panels;

[0083] 300, power grid;

[0084] 400, fuel generator;

[0085] 510, important load; 520, secondary load; 530, smart load;

[0086] 600, photovoltaic grid-connected inverter;

[0087] 700. Smart terminal. DETAILED DESCRIPTION

[0088] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings to make the advantages and features of the present invention more easily understood by those skilled in the art. It should be noted that the description of these embodiments is intended to facilitate understanding of the present invention and does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0089] Figure 1 The topology diagram of a household photovoltaic energy storage system using a household photovoltaic energy storage inverter is shown, wherein the household photovoltaic energy storage inverter is in the oil engine operation mode. Figure 1 As shown, the household photovoltaic energy storage inverter 100 of this embodiment includes an inverter module 110 and a battery 120. The inverter module 110 implements power interaction between the DC bus circuit and the AC measurement. The photovoltaic energy storage inverter 100 has a DC input side for connecting the photovoltaic panel 200 and the battery 120. Furthermore, the photovoltaic energy storage inverter 100 also includes a PV module for transmitting PV power to the inverter DC bus circuit. The photovoltaic panel 200 converts solar energy into DC power and transmits it to the household photovoltaic energy storage inverter 100 (specifically, the PV module); the power of the battery 120 can also be dispatched by the inverter module 110. The battery 120 is connected to the BAT port of the inverter module 110 via a power line, and power interaction between the battery and the DC bus circuit is realized through the battery module to achieve bidirectional power transmission between the battery 120 and the inverter module 110, and realize power release and charging; the battery 120 is also connected to the CAN port of the inverter module 110 via the CAN bus to exchange information, including the actual SOC (State of Charge) value of the battery 120, so that the inverter module 110 can know the remaining power of the battery 120.

[0090] The user's loads include critical loads 510 and secondary loads 520. Critical loads 510 are essential household appliances that must be protected from power outages, such as lighting and refrigerators. Secondary loads 520 are secondary loads within the home that can operate as needed and tolerate power outages. When the grid 300 is active, these loads are powered by the grid 300. When the household photovoltaic energy storage inverter 100 is disconnected from the grid 300, the household photovoltaic energy storage inverter 100 does not supply power to these loads.

[0091] This household photovoltaic energy storage system is connected to a fuel generator 400, such as a diesel generator. In the event of a grid 300 outage or grid 300 failure, the fuel generator 400 can power the user's critical load 510. The inverter module 110 coordinates power from the fuel generator 400, battery 120, and photovoltaic panel 200, ensuring uninterrupted operation of the critical load 510.

[0092] Combine Figure 1 and Figure 2 As shown, the household photovoltaic energy storage inverter 100 also includes: an inverter output switch 150, a first end of which is connected to the AC output end of the inverter module 110 to switch the output state of the inverter module 110; a power supply port EPS, which is used to connect the user's important load 510, and the power supply port EPS is connected to the second end of the inverter output switch 150 to supply power to the power supply port EPS; an oil generator port Gen, which can be connected to a fuel generator 400 (also referred to as "oil generator"); and an oil generator port switch 170, which is connected between the power supply port EPS and the oil generator port Gen. Among them, the household photovoltaic energy storage inverter 100 has an oil engine operation mode. In the oil engine operation mode, the inverter output switch 150 remains closed. When the oil engine port switch 170 is disconnected, the inverter module 110 is configured to convert the power from the photovoltaic panel 200 and / or the battery 120 to supply power to the important load 510 or the power grid 300 to supply power to the important load 510; when the oil engine port switch 170 is closed, the fuel generator 400 supplies power to the important load 510.

[0093] In the case of a grid 300 , the household photovoltaic energy storage inverter 100 further includes: a grid port GRID, which is used to connect to the grid 300 ; and a grid port switch 160 , which is connected between the inverter output switch 150 and the grid port GRID. In the diesel engine operation mode, the household photovoltaic energy storage inverter 100 has a grid-connected working state, an off-grid working state and a diesel engine-connected working state. In the grid-connected working state, the inverter output switch 150 and the grid port switch 160 are closed, the diesel engine port switch 170 is disconnected, and the grid 300 supplies power to the important load 510; in the off-grid working state, the inverter output switch 150 is closed, the diesel engine port switch 170 and the grid port switch 160 are disconnected, and the inverter module 110 is configured to convert the power from the photovoltaic panel 200 and / or the battery 120 and supply power to the important load 510; in the diesel engine-connected working state, the inverter output switch 150 and the diesel engine port switch 170 are closed, the grid port switch 160 is disconnected, and the fuel generator 400 supplies power to the important load 510.

[0094] like Figure 1 and Figure 2As shown, in the diesel generator operation mode, the household photovoltaic energy storage system includes the user's important load 510, the fuel generator 400 and the household photovoltaic energy storage inverter 100. The important load 510 is connected to the power supply port EPS of the household photovoltaic energy storage inverter 100, and the diesel generator 400 is connected to the diesel generator port Gen of the household photovoltaic energy storage inverter 100.

[0095] The inverter output switch 150 includes a relay group K1; the grid port switch 160 includes multiple cascaded relay groups, specifically two cascaded relay groups K2 and K3; and the diesel engine port switch 170 includes a relay group K4. In this embodiment, the residential photovoltaic energy storage inverter 100 is a three-phase inverter, with relays installed on the A, B, C, and N phases. The control terminal of each relay is electrically connected to the control module of the residential photovoltaic energy storage inverter 100, allowing for unified control by the residential photovoltaic energy storage inverter 100 to achieve on-off switching of each relay.

[0096] The residential photovoltaic energy storage inverter 100 also includes a GFCI module 130 connected to the AC output side of the inverter module 110. An inverter output switch 150 is provided on the output side of the GFCI module 130. The residential photovoltaic energy storage inverter 100 also includes multiple EMC modules 140. The inverter module 110, the GFCI module 130, and two EMC modules 140 (EMC1 and EMC2) are connected in series. A grid port switch 160 is connected between the two EMC modules 140. A PE-OFF switch is also provided on the N-phase line on the output side of the GFCI module 130.

[0097] The household photovoltaic energy storage inverter 100 further includes a sampling module for collecting the AC output voltage and current of the inverter module 110 , the voltage and current of the power supply port, and the voltage and current of the diesel generator port. Figure 2 In the figure, CT1 is the inverter output current sampling, V1 is the inverter voltage sampling; CT 2 is the oil generator port current sampling, V2 is the oil generator port voltage sampling; V3 is the grid port current sampling, CT3 is the load port current sampling, and V4 is the load voltage sampling.

[0098] Furthermore, the output side of the inverter module 110 has a first power line 181, which connects the inverter module 110 to the power grid 300 (grid port) via the first power line 181. The inverter output switch 150 and the grid port switch 160 are located on the first power line 181. The inverter module 110 is connected to the user's important load 510 (power supply port) via a second power line 182, where the second power line 182 is connected to the intermediate node between the inverter output switch 150 and the grid port switch 160 on the first power line 181. The inverter module 110 is connected to the fuel-powered generator 400 (generator port) via a third power line 183, where the generator port switch 170 is located on the third power line 183, which is connected to the intermediate node between the inverter output switch 150 and the grid port switch 160 on the first power line 181. When operating in parallel with the diesel generator, the household photovoltaic energy storage inverter 100 transmits power from the fuel generator 400 to the critical load 510 via the third power line 183, the first power line 181, and the second power line 182. In this embodiment, the internal wiring (first power line 181, second power line 182, and third power line 183) and switches (relays K1 through K4, etc.) of the photovoltaic energy storage inverter are used to connect and disconnect the diesel generator.

[0099] In this household photovoltaic energy storage system, the household photovoltaic energy storage inverter 100 is capable of interactive communication with a smart terminal 700. The smart terminal 700 can be a smartphone or tablet computer, etc., with a built-in application program (APP). The operating parameters of the household photovoltaic energy storage inverter 100 can be set through the smart terminal 700. Specifically, the smart terminal 700 can use wireless transmission methods such as Wi-Fi to transmit information to the household photovoltaic energy storage inverter 100.

[0100] The photovoltaic energy storage inverter 100 can adjust the output power of the photovoltaic grid-connected inverter based on the load and battery power requirements. This adjustment is achieved by controlling the output voltage and frequency of the photovoltaic energy storage inverter. The photovoltaic energy storage inverter 100 integrates an EMS control function, which controls battery charging or discharging according to system requirements to achieve maximum system production efficiency. It also outputs commands to adjust the output voltage and frequency of the energy storage inverter to adjust the output power of the photovoltaic grid-connected inverter.

[0101] like Figure 3 As shown, the control method of the household photovoltaic energy storage inverter 100 includes the following steps of connecting to the oil generator:

[0102] The household photovoltaic energy storage inverter 100 is placed in the oil generator operation mode, and the power supply port of the household photovoltaic energy storage inverter 100 is connected to the user's important load 510;

[0103] Real-time detection of the operating status of the household photovoltaic energy storage inverter 100. When the set oil generator start-up conditions are met, the household photovoltaic energy storage inverter 100 sends a start-up signal to the oil generator 400 to start the oil generator 400.

[0104] The AC output voltage of the household photovoltaic energy storage inverter 100 is controlled to follow the voltage of the fuel generator 400. After the AC output voltage reaches the same frequency and phase as the voltage of the fuel generator 400, the oil generator port switch 170 is closed, and the fuel generator 400 supplies power to the important load 510.

[0105] If there is a power grid 300, the control method further includes a grid-connected switching step and an off-grid switching step. The grid-connected switching step specifically includes: closing the grid port switch 160 between the inverter module 110 of the household photovoltaic energy storage inverter 100 and the grid port, closing the inverter output switch 150 of the inverter module 110 of the household photovoltaic energy storage inverter 100, and opening the diesel port switch 170, thereby connecting the inverter module 110 to the power grid 300. The off-grid switching step specifically includes: closing the grid port switch 160 between the inverter module 110 of the household photovoltaic energy storage inverter 100 and the grid port, closing the inverter output switch 150 of the inverter module 110 of the household photovoltaic energy storage inverter 100, and opening the diesel port switch 170, thereby disconnecting the inverter module 110 from the power grid 300. Furthermore, during the diesel-generator connection step, the inverter output switch 150 of the inverter module 110 of the household photovoltaic energy storage inverter 100 remains closed. The important load 510 is continuously powered by the power from the photovoltaic panel 200 and / or the battery 120 converted by the inverter module 110 , the power from the grid 300 , or the power from the fuel generator 400 .

[0106] The conditions for closing the oil generator port switch are user-configurable. For example, the oil generator port switch can be closed when the inverter module is connected to the grid; or when the actual state of charge (SOC) of the battery exceeds the preset state of charge (SOC); or when the photovoltaic panel generates sufficient power and has excess power to feed into the grid.

[0107] Furthermore, compared to conventional PV energy storage inverters, this embodiment incorporates a multi-purpose diesel generator port, designed to fulfill different functions. Depending on the application requirements, the diesel generator port can be connected to a diesel generator, a smart load, or a PV grid-connected inverter.

[0108] Oil engine operation mode:

[0109] In the diesel engine operation mode, the diesel generator connected to the diesel engine port can serve as a backup power source to supply power to the important load 510 in the home. The specific control process in the diesel engine mode is as follows:

[0110] (1) The inverter detects the operation status of the photovoltaic energy storage system in real time. After the diesel generator start-up conditions set by the user on the APP are met, the inverter can send a start signal to the diesel generator through the control signal line connected to the diesel generator to start the diesel generator.

[0111] (2) After the diesel generator runs stably, control the inverter output to follow the engine voltage. When the inverter output voltage and the engine voltage reach the same frequency and phase, close relay K4 to make the inverter run in parallel with the engine, and the diesel generator will supply power to the backup load.

[0112] (3) In particular, the AC side operating modes of the photovoltaic energy storage inverter include grid-connected operation, off-grid operation, and parallel operation with an oil generator. The inverter's operating mode adds a parallel operation with an oil generator. When there is a grid 300, the inverter operates in the grid-connected mode, the grid relays K2 and K3 are closed, the inverter relay K1 is closed, the oil generator relay K4 is disconnected, and the oil generator is shut down. When operating off-grid, the grid relays K2 and K3 are disconnected, the oil generator relay K4 is disconnected, the inverter relay K1 is closed, and the PV and battery 120 supply power to the backup load through the inverter. When operating with an oil generator, the grid relays K2 and K3 are disconnected, the inverter relay K1 is closed, the oil generator relay K4 is closed, and the diesel generator supplies power to the backup load.

[0113] (4) When switching between grid-connected mode and diesel engine mode, both first switch to off-grid operation mode, and then switch to diesel engine mode / grid-connected mode. The phase sequence of the diesel engine and the grid 300 needs to be ensured to be consistent during wiring. In order to avoid possible errors, the inverter has the ability to adapt to the phase sequence of the grid 300 and the diesel engine, and has the function of detecting the inconsistency between the phase sequence of the diesel engine and the phase sequence of the grid 300. When switching between the diesel engine and the grid through the off-grid mode, if it is detected that the phase sequence of the diesel generator disconnection is inconsistent with the phase sequence of the grid 300 disconnection, the inverter reports a diesel engine phase sequence error fault (adds a fault code), and the inverter shuts down to ensure system safety.

[0114] (5) As mentioned above, the inverter's diesel engine operation mode has flexible application settings to meet different usage scenarios. Users can set the diesel engine's operating conditions through the APP, including diesel engine enable control, battery SOC conditions for diesel engine startup and launch, diesel engine power limit, diesel engine charging settings for battery 120 (charging enable and charging power) and diesel engine operating time.

[0115] (6) The settings for enabling the diesel engine and starting / exiting the SOC provide the diesel engine with the possibility to meet different application scenarios. Users can set the conditions for the diesel engine to enter and exit the system according to actual needs. When there is no grid 300 and the battery SOC is lower than the set SOC, the inverter will control the diesel engine to connect to the system. When the battery 120 reaches the set diesel engine exit SOC, the inverter will control the diesel engine to disconnect and issue a diesel engine stop command to stop the diesel engine.

[0116] (7) After the diesel generator is connected, in addition to supplying power to the load, it can also charge the battery 120 according to the user's settings. When the diesel generator is required to charge the battery 120, the user needs to enable the diesel generator to charge the battery 120 and set the charging power. Conversely, if the user turns off the diesel generator to charge the battery 120, the diesel generator will not charge the battery 120. It should be noted that if the power of the photovoltaic panel 200PV can always be used to charge the battery 120, it ensures that power is not wasted.

[0117] (8) The inverter has the protection function of the oil engine port response, including port overload protection (port power / current exceeds the user's set power or the inverter's limit threshold), port over-voltage and under-frequency protection, oil engine power backflow protection (to prevent the inverter power from entering the oil engine and causing possible damage to the oil engine), and oil engine port mode setting error protection.

[0118] (9) Generally, when the grid 300 is normal, the inverter operates in the grid-connected operation mode, and the grid-connected operation is the inverter's priority operation mode. In the diesel generator operation state, after detecting that the grid 300 is normally connected, the inverter will switch the control system to the grid-connected operation. At the same time, the APP provides a forced off-grid operation setting. If the user sets the forced off-grid enable, the inverter will not operate in the grid 300.

[0119] When the generator port is disconnected, the PV grid-connected inverter stops operating. When the generator port is closed, the PV grid-connected inverter joins the system. Under grid-connected operation, the PV energy storage inverter switches to off-grid operation. The PV energy storage inverter's EMS module calculates the system's power requirements in real time and then adjusts its own output voltage and / or frequency to regulate the power of the PV grid-connected inverter connected to the generator port, while also controlling battery charging and discharging.

[0120] like Figure 4As shown, the household photovoltaic energy storage inverter 100 also has a smart load operation mode. In this smart load operation mode, the generator port is configured to connect to a smart load 530. When the generator port switch 170 is closed, the inverter module 110 is configured to convert power from the photovoltaic panel 200 and / or the battery 120 to power the important load 510 and the smart load 530, or to power the important load 510 and the smart load 530 from the grid 300. When the generator port switch 170 is open, the inverter module 110 stops supplying power to the smart load 530. The generator port switch 170 is allowed to close when the inverter module 110 is connected to the grid 300; or when the actual state of charge (SOC) value of the battery 120 is greater than a preset state of charge (SOC) value.

[0121] Reference Figure 4 In the smart load operation mode, the household photovoltaic energy storage system includes the user's important load 510, the smart load 530 and the household photovoltaic energy storage inverter 100. The important load 510 is connected to the power supply port of the household photovoltaic energy storage inverter 100, and the smart load 530 is connected to the diesel generator port of the household photovoltaic energy storage inverter 100.

[0122] In smart load operation mode, the inverter can power smart load 530 connected to the diesel generator according to user settings. Smart load 530 is typically a non-essential household load. When system energy is sufficient, the inverter controls relay K4 to close and power smart load 530. When system energy is limited, the inverter controls relay K4 to open, disconnecting the smart load 530.

[0123] In this mode, the control method of the household photovoltaic energy storage inverter 100 includes:

[0124] The household photovoltaic energy storage inverter 100 is placed in a smart load operation mode, and the power supply of the household photovoltaic energy storage inverter 100 is disconnected from the user's important load 510;

[0125] After detecting that the household photovoltaic energy storage inverter 100 meets the conditions for connecting to the smart load 530, the oil generator port switch 170 is closed to connect to the smart load 530;

[0126] After detecting that the household photovoltaic energy storage inverter 100 does not meet the conditions for disconnecting the smart load 530, the diesel engine port switch 170 is disconnected to disconnect the smart load 530.

[0127] Conditions for enabling smart load 530 include: the actual SOC value of battery 120 is greater than a preset SOC value, or inverter module 110 is connected to grid 300. Conditions for disconnecting smart load 530 include: the diesel engine port disconnects the enable signal, or the actual SOC value of battery 120 is no greater than a preset SOC value. Critical load 510 is continuously powered by power from photovoltaic panel 200 and / or battery 120, converted by inverter module 110, or from grid 300.

[0128] The control process of the smart load operation mode is as follows:

[0129] (1) Enable the diesel engine port and set the diesel engine port mode to smart load 530 mode. The APP sets the switch when the smart load 530 is always connected, the SOC value when the smart load 530 is connected, and the battery SOC value when the smart load 530 is disconnected.

[0130] (2) After the inverter is started, it checks whether the conditions for connecting the smart load 530 are met. If the conditions for connecting the smart load 530 are met, the relay K4 is closed to connect the smart load 530. Otherwise, the relay K4 remains open. The conditions for connecting the smart load 530 include being connected to the grid and the switch for connecting the smart load 530 is always open during the grid connection, or the actual SOC value of the battery 120 is greater than the set SOC value for connecting the smart load.

[0131] (3) After the smart load 530 is engaged, if the conditions for disconnecting the smart load 530 are met, the inverter controls the K4 relay to disconnect. The conditions for disconnecting the smart load 530 are: the diesel generator disconnect enable is turned off, the battery SOC is lower than the SOC for disconnecting the smart load 530, and the smart load 530 is operating in off-grid or grid-connected mode with the smart load 530 switch always turned off.

[0132] (4) In order to prevent the protection caused by overload from affecting the reliable power supply of the backup load, when a condition that may trigger the inverter overload occurs, the inverter controls the smart load 530 to disconnect and not connect again within a certain period of time (for example, 1 hour) to ensure stable operation of the system.

[0133] like Figure 5As shown, the household photovoltaic energy storage inverter 100 also has a photovoltaic grid-connected inverter mode. In this mode, the diesel generator port is configured to connect to a photovoltaic grid-connected inverter 600. The photovoltaic grid-connected inverter 600 itself does not store electricity and does not have a battery 120. When the diesel generator port switch 170 is closed, the inverter module 110 is configured to convert the power from the photovoltaic grid-connected inverter 600 to power the important load 510 or charge the battery 120. In the photovoltaic grid-connected inverter mode, if the household photovoltaic energy storage inverter 100 is grid-connected and the diesel generator port switch 170 is closed, if the power grid 300 is abnormal, the diesel generator port switch 170 is opened. After the household photovoltaic energy storage inverter 100 switches to off-grid operation, the diesel generator port switch 170 is closed. If the household photovoltaic energy storage inverter 100 switches from off-grid operation to grid-connected operation, the diesel engine port switch 170 is disconnected. After the household photovoltaic energy storage inverter 100 is grid-connected, the diesel engine port switch 170 is closed.

[0134] Reference Figure 5 In the photovoltaic grid-connected inverter mode, the household photovoltaic energy storage system includes the user's important load 510, the photovoltaic grid-connected inverter 600 and the household photovoltaic energy storage inverter 100. The important load 510 is connected to the power supply port of the household photovoltaic energy storage inverter 100, and the photovoltaic grid-connected inverter 600 is connected to the diesel engine port of the household photovoltaic energy storage inverter 100.

[0135] In this mode, the control method for the household photovoltaic energy storage inverter 100 includes the following steps for connecting the photovoltaic grid-connected inverter 600: placing the household photovoltaic energy storage inverter 100 in photovoltaic grid-connected inverter mode, connecting the power supply port of the household photovoltaic energy storage inverter 100 to the user's important load 510, and connecting the diesel generator port of the household photovoltaic energy storage inverter 100 to the photovoltaic grid-connected inverter 600, so that power from the photovoltaic grid-connected inverter 600 is used to power the important load 510 or charge the battery 120. The important load 510 is continuously powered by power from the photovoltaic panel 200 and / or battery 120 converted by the inverter module 110, power from the power grid 300, or power from the photovoltaic grid-connected inverter 600.

[0136] The household photovoltaic energy storage inverter 100 and the photovoltaic grid-connected inverter 600 exchange information via a communication line. The household photovoltaic energy storage inverter 100 transmits the acquired grid 300 and current information to the photovoltaic grid-connected inverter 600 for reverse flow control. It should be noted that communication between the photovoltaic energy storage inverter 100 and the photovoltaic grid-connected inverter 600 is not required for the system, but rather a measure to optimize system performance. In the absence of communication, the energy storage inverter 100 can control the power production of the entire system by adjusting its own output power and output voltage.

[0137] When the grid 300 is available, the grid port switch 160 between the inverter module 110 and the grid port of the household photovoltaic energy storage inverter 100 is closed, and the diesel engine port switch 170 is closed to make the voltage of the grid 300 reach the photovoltaic grid-connected inverter 600;

[0138] During grid-connected operation, if an abnormality occurs in the grid 300, the grid port switch 160 and the diesel generator port switch 170 are closed; after the user's photovoltaic energy storage inverter switches to off-grid operation and the operation is stable, the diesel generator port switch 170 is closed;

[0139] During off-grid operation, after the household photovoltaic energy storage inverter 100 is in stable off-grid operation, the diesel engine port is closed, so that the output voltage of the household photovoltaic energy storage inverter 100 reaches the output voltage of the photovoltaic grid-connected inverter 600;

[0140] During off-grid operation, if the output power of the photovoltaic grid-connected inverter 600 is less than the power of the important load 510, the household photovoltaic energy storage inverter 100 supplies power to the important load 510; if the output power of the photovoltaic grid-connected inverter 600 is greater than the power of the important load 510, the photovoltaic grid-connected inverter 600 supplies power to the important load 510, and the household photovoltaic energy storage inverter allocates excess power from the photovoltaic grid-connected inverter 600 to charge the battery 120.

[0141] Typically, the PV grid-connected inverter 600 and the household PV energy storage inverter 100 are connected in parallel at the PCC (Point of Common Coupling) on ​​the grid 300. This parallel connection has the disadvantage that when the grid 300 is disconnected, the household PV energy storage inverter 100 will operate off-grid (off-grid operation means the household PV energy storage inverter 100 is disconnected from the grid 300 and independently supplies power to the backup load), while the PV grid-connected inverter 600 will shut down, resulting in power wasted from the photovoltaic panels 200 connected to the PV grid-connected inverter 600. Figure 5 The illustrated household photovoltaic energy storage inverter 100 and system can solve this problem. In this solution, a photovoltaic grid-connected inverter 600 is connected to the household photovoltaic energy storage inverter 100 via the diesel generator port. During off-grid operation, the photovoltaic grid-connected inverter 600 can also operate in parallel with the household photovoltaic energy storage inverter 100. The output power of the photovoltaic grid-connected inverter 600 can supply the load and can also charge the battery 120 through the household photovoltaic energy storage inverter 100.

[0142] The specific control scheme of the photovoltaic grid-connected inverter mode is:

[0143] (1) The grid 300 interface of the photovoltaic grid-connected inverter 600 is connected to the diesel engine port of the household photovoltaic energy storage inverter 100. The household photovoltaic energy storage inverter 100 is connected to the grid-connected inverter via an RS-485 communication line to exchange information.

[0144] (2) During grid-connected operation, the photovoltaic energy storage inverter is connected to the electric meter at the PCC to obtain the electric meter information, and transmits the electric meter information to the photovoltaic grid-connected inverter 600 through communication with the photovoltaic grid-connected inverter 600 for anti-backflow control.

[0145] (3) When the grid 300 is present, the photovoltaic energy storage inverter closes its own grid-side relays K2 and K3, and then closes the diesel engine port relay K4, so that the voltage of the grid 300 reaches the photovoltaic grid-connected inverter 600.

[0146] (4) During off-grid operation, the photovoltaic energy storage inverter starts running first. After the off-grid operation is stable, the photovoltaic energy storage inverter sends a signal to close the diesel engine port relay K4, so that the output voltage of the photovoltaic energy storage inverter reaches the photovoltaic grid-connected inverter 600.

[0147] (5) After the K4 relay is closed, the grid-connected grid voltage 300 or the output voltage of the PV energy storage inverter when off-grid reaches the grid port of the PV grid-connected inverter 600. The PV grid-connected inverter 600 will detect the voltage at the grid port and start the operation in parallel with the PV energy storage inverter according to its own operating logic.

[0148] (6) During off-grid operation, the photovoltaic grid-connected inverter 600 outputs power at its maximum power, and the photovoltaic energy storage inverter manages the system energy. When the photovoltaic grid-connected inverter 600 outputs insufficient load power, the energy storage inverter outputs power to supply the load; when the photovoltaic grid-connected inverter 600 outputs power that satisfies the load and there is excess power, the energy storage inverter allocates the excess power to charge the battery 120 through the energy storage inverter.

[0149] (7) When an abnormality occurs in the grid 300 during grid-connected operation, the energy storage inverter disconnects relays K2 and K3 and at the same time disconnects relay K4 to stop the operation of the photovoltaic inverter; at the same time, the energy storage machine completes the grid-connected and off-grid switching, and after the off-grid operation is stable, relay K4 is closed to put the photovoltaic grid-connected machine into the system.

[0150] (8) During off-grid operation, when the energy storage inverter detects that the grid 300 has returned to normal and needs to switch from off-grid operation to grid-connected operation, the energy storage inverter disconnects the K4 relay to stop the grid-connected inverter. After the energy storage inverter completes the switch from off-grid operation to grid-connected operation, the energy storage inverter closes the relay K4 to put the photovoltaic grid-connected machine into the system.

[0151] The household photovoltaic energy storage inverter 100 of this embodiment integrates the diesel generator switching circuit and switching control, eliminating the need for additional switching devices. When the system requires the diesel generator, the inverter can control the start of the diesel generator to power the important load 510. This has the advantages of high system integration, automation without human intervention, high system reliability and good economic efficiency. The diesel generator disconnection can meet different usage scenarios, providing system flexibility and scalability. The connection method between the household photovoltaic energy storage inverter 100 and the photovoltaic grid-connected machine allows the photovoltaic grid-connected inverter 600 to be connected in parallel to the energy storage inverter for operation in the absence of the power grid 300. The energy of the photovoltaic panels connected to the grid-connected inverter can be used for load or stored in the battery 120 through the energy storage inverter (the stored energy can be sold to the power grid 300 after load or grid connection at night), avoiding energy waste and improving the applicability, reliability and economy of the user system.

[0152] As used in this specification and claims, the terms "comprises" and "include" merely indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list; a method or apparatus may also include other steps or elements. The term "and / or" as used herein includes any combination of one or more of the associated listed items.

[0153] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art. If a definition used herein conflicts or is inconsistent with a definition in other published documents, the definition used herein shall prevail.

[0154] As used in this specification and claims, the terms "comprises" and "include" merely indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list; a method or apparatus may also include other steps or elements. The term "and / or" as used herein includes any combination of one or more of the associated listed items.

[0155] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above 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 to implement: 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.

[0156] Those skilled in the art will appreciate that all or part of the steps in the method for implementing the above-mentioned embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0157] In addition, the functional units in the embodiments may be integrated into a single processing module, each unit may exist physically separately, or two or more units may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or software functional modules. If the integrated modules are implemented in the form of software functional modules and sold or used as independent products, they may also be stored in a computer-readable storage medium.

[0158] The above embodiment is intended only to illustrate the technical concepts and features of the present invention and is a preferred embodiment. Its purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. It is not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made based on the principles of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A household photovoltaic energy storage inverter having a DC port for connecting a photovoltaic panel and a battery, characterized in that: The household photovoltaic energy storage inverter includes: an inverter output switch, a first end of which is connected to the AC output end of the inverter module to switch the output state of the inverter module; A power supply port, which is used to connect an important load of a user, and the power supply port is connected to the second end of the inverter output switch to supply power to the power supply port; The diesel generator port can be connected to a fuel generator, smart load, or photovoltaic grid-connected inverter; an oil engine port switch, connected between the power supply port and the oil engine port; In which, the household photovoltaic energy storage inverter has an oil engine operation mode. In the oil engine operation mode, the inverter output switch remains closed. When the oil engine port switch is disconnected, the inverter module is configured to convert the power from the photovoltaic panel and / or battery to supply power to the important load or to supply power to the important load from the power grid; when the oil engine port switch is closed, the fuel generator supplies power to the important load.

2. The household photovoltaic energy storage inverter according to claim 1, characterized in that: The household photovoltaic energy storage inverter also includes: A grid port, which is used to connect to a grid; a grid port switch connected between the inverter output switch and the grid port; In the diesel engine operation mode, the household photovoltaic energy storage inverter has a grid-connected working state, an off-grid working state and a diesel engine-connected working state. In the grid-connected working state, the inverter output switch and the grid port switch are closed, the diesel engine port switch is disconnected, and the grid supplies power to the important loads. In the off-grid working state, the inverter output switch is closed, the diesel engine port switch and the grid port switch are disconnected, and the inverter module is configured to convert power from the photovoltaic panel and / or the battery and supply power to the important loads. In the diesel engine-connected working state, the inverter output switch and the diesel engine port switch are closed, the grid port switch is disconnected, and the fuel generator supplies power to the important loads and charges the battery. The output side of the inverter module has a first power line, the power supply port is connected to the first power line through a second power line, and the diesel generator port is connected to the first power line through a third power line. When the household photovoltaic energy storage inverter is in the diesel generator parallel working state, the diesel generator port and the power supply port are connected through the third power line, the first power line and the second power line to transmit power from the fuel generator to important loads.

3. The household photovoltaic energy storage inverter according to claim 1 or 2, characterized in that: The household photovoltaic energy storage inverter also has a smart load operation mode. In the smart load operation mode, the oil engine port is configured to be connected to a smart load. When the oil engine port switch is closed, the inverter module is configured to convert the power from the photovoltaic panel and / or battery to power the important load and the smart load, or to power the important load and the smart load from the power grid; when the oil engine port switch is disconnected, the inverter module stops supplying power to the smart load.

4. The household photovoltaic energy storage inverter according to claim 3, characterized in that: The conditions for closing the oil engine port switch are configured by the user; When the inverter module is connected to the grid, the oil engine port switch is allowed to be closed; or when the actual SOC value of the battery is greater than the preset SOC value, the oil engine port switch is allowed to be closed; Alternatively, when the photovoltaic panel generates a large amount of power and there is excess power to feed into the grid, the diesel engine port switch is allowed to be closed; The output side of the inverter module has a first power line, the power supply port is connected to the first power line through a second power line, and the diesel engine port is connected to the first power line through a third power line. In the smart load operation mode, the household photovoltaic energy storage inverter connects the inverter module and the diesel engine port through the third power line and the first power line to supply power to the smart load.

5. The household photovoltaic energy storage inverter according to claim 1 or 2, characterized in that: The household photovoltaic energy storage inverter also has a photovoltaic grid-connected inverter mode. In the photovoltaic grid-connected inverter mode, the oil engine port is configured to be connected to a photovoltaic grid-connected inverter. When the oil engine port switch is closed, the inverter module is configured to convert the power from the photovoltaic grid-connected inverter to power the important load or charge the battery.

6. The household photovoltaic energy storage inverter according to claim 5, characterized in that: In the photovoltaic grid-connected inverter mode, when the household photovoltaic energy storage inverter is grid-connected and the diesel engine port switch is closed, if the grid is abnormal, the diesel engine port switch is disconnected, and after the household photovoltaic energy storage inverter switches to off-grid operation, the diesel engine port switch is closed; If the household photovoltaic energy storage inverter switches from off-grid operation to grid-connected operation, the diesel engine port switch is disconnected. After the household photovoltaic energy storage inverter is grid-connected, the diesel engine port switch is closed. After the oil engine port is disconnected, the photovoltaic grid-connected inverter will stop working. After the oil engine port is closed, the photovoltaic grid-connected inverter will be integrated into the system to work. Under the grid-connected operation condition, when the photovoltaic energy storage inverter switches to the off-grid operation condition, the EMS module of the photovoltaic energy storage inverter calculates the power required by the system in real time, and then adjusts the power of the photovoltaic grid-connected inverter connected to the diesel engine port by adjusting its own output voltage and / or frequency, while controlling the battery to charge or discharge; The output side of the inverter module has a first power line, the power supply port is connected to the first power line through a second power line, and the diesel engine port is connected to the first power line through a third power line. When the household photovoltaic energy storage inverter is in photovoltaic grid-connected inverter mode, the diesel engine port and the power supply port are connected through the third power line, the first power line and the second power line to transmit power from the photovoltaic grid-connected inverter to important loads.

7. The household photovoltaic energy storage inverter according to claim 2, characterized in that: The inverter output switch includes a relay group, the oil engine port switch includes a relay group, and the grid port switch includes multiple relay groups cascaded with each other; The household photovoltaic energy storage inverter further includes a GFCI module connected to the AC output side of the inverter module, and the inverter output switch is provided on the output side of the GFCI module; The household photovoltaic energy storage inverter further includes a sampling module for collecting the AC output voltage and current of the inverter module, the voltage and current of the power supply port, and the voltage and current of the oil generator port.

8. A household photovoltaic energy storage system, characterized in that: It includes the user's important load, a fuel generator and the household photovoltaic energy storage inverter according to any one of claims 1 to 7, wherein the important load is connected to the power supply port of the household photovoltaic energy storage inverter, and the oil generator is connected to the oil generator port of the household photovoltaic energy storage inverter.

9. A household photovoltaic energy storage system, characterized in that: The utility model comprises an important load of the user, a smart load and a household photovoltaic energy storage inverter according to any one of claims 1 to 7, wherein the important load is connected to the power supply port of the household photovoltaic energy storage inverter, and the smart load is connected to the oil generator port of the household photovoltaic energy storage inverter.

10. A household photovoltaic energy storage system, characterized in that: It includes the user's important load, a photovoltaic grid-connected inverter and the household photovoltaic energy storage inverter according to any one of claims 1 to 7, wherein the important load is connected to the power supply port of the household photovoltaic energy storage inverter, and the photovoltaic grid-connected inverter is connected to the diesel engine port of the household photovoltaic energy storage inverter.

11. A control method for a household photovoltaic energy storage inverter according to any one of claims 1 to 7, characterized in that: The control method includes the following steps of combining the oil generators: The household photovoltaic energy storage inverter is placed in an oil engine operation mode, and the power supply port of the household photovoltaic energy storage inverter is connected to the user's important load; Real-time detection of the operating status of the household photovoltaic energy storage inverter. When the set diesel generator start-up conditions are met, the household photovoltaic energy storage inverter sends a start-up signal to the diesel generator to start the diesel generator; Controlling the AC output voltage of the household photovoltaic energy storage inverter to follow the voltage of the fuel generator, and after reaching the same frequency and phase as the voltage of the fuel generator, closing the oil generator port switch, so that the fuel generator supplies power to the important load; If there is a power grid, the control method further includes: Grid-connected switching step: closing the grid port switch between the inverter module of the household photovoltaic energy storage inverter and the grid port, closing the inverter output switch of the inverter module of the household photovoltaic energy storage inverter, and opening the diesel engine port switch, so that the inverter module is connected to the grid; Off-grid switching step: closing the grid port switch between the inverter module of the household photovoltaic energy storage inverter and the grid port, closing the inverter output switch of the inverter module of the household photovoltaic energy storage inverter, and opening the diesel engine port switch, so that the inverter module is disconnected from the grid; Wherein, in the oil-generating unit paralleling step, the inverter output switch of the inverter module of the household photovoltaic energy storage inverter is kept closed; The important load is continuously powered by electricity from photovoltaic panels and / or batteries converted by an inverter module, electricity from a power grid, or electricity from the fuel generator.

12. A control method for a household photovoltaic energy storage inverter according to any one of claims 1 to 7, characterized in that: The control method includes: The household photovoltaic energy storage inverter is placed in a smart load operation mode, and the power supply of the household photovoltaic energy storage inverter is disconnected from the important load of the user; After detecting that the household photovoltaic energy storage inverter meets the conditions for connecting to a smart load, the oil generator port switch is closed to connect to the smart load; After detecting that the household photovoltaic energy storage inverter does not meet the conditions for disconnecting the smart load, the oil engine port switch is turned off to disconnect the smart load; The conditions for carrying smart loads include: the actual SOC value of the battery is greater than the preset SOC value, or the inverter module is connected to the grid, or the photovoltaic panel generates power that is sufficient to feed the grid in addition to meeting the needs of important loads and battery charging; The conditions for disconnecting the smart load include: the oil engine port disconnecting the enable signal, or the actual SOC value of the battery is not greater than the preset SOC value; or the power of the photovoltaic panel is reduced so that there is no excess energy; The switching-on or switching-off conditions of the intelligent load are configured by the user according to the needs; The important loads are continuously powered by electricity from photovoltaic panels and / or batteries converted by the inverter module or by electricity from the power grid.

13. A control method for a household photovoltaic energy storage inverter according to any one of claims 1 to 7, characterized in that: The following steps are included for connecting the photovoltaic grid-connected inverter: The household photovoltaic energy storage inverter is placed in a photovoltaic grid-connected inverter mode, with the power supply port of the household photovoltaic energy storage inverter connected to the user's important load, and the diesel generator port of the household photovoltaic energy storage inverter connected to the photovoltaic grid-connected inverter, so that the power from the photovoltaic grid-connected inverter is used to power the important load or charge the battery; The important load is continuously powered by electricity from photovoltaic panels and / or batteries converted by an inverter module, electricity from a power grid, or electricity from the photovoltaic grid-connected inverter.

14. The control method according to claim 13, characterized in that: The household photovoltaic energy storage inverter can exchange information with the photovoltaic grid-connected inverter through a communication line. The household photovoltaic energy storage inverter transmits the acquired grid and current information to the photovoltaic grid-connected inverter for backflow prevention control. When there is a grid, after closing the grid port switch between the inverter module and the grid port of the household photovoltaic energy storage inverter, close the diesel engine port switch to make the grid voltage reach the photovoltaic grid-connected inverter; During grid-connected operation, if a grid abnormality occurs, the grid port switch and the diesel engine port switch are disconnected; after the user's photovoltaic energy storage inverter switches to off-grid operation and the operation is stable, the diesel engine port switch is closed; During off-grid startup, after the household photovoltaic energy storage inverter is stable in off-grid operation, the diesel engine port is closed, so that the output voltage of the household photovoltaic energy storage inverter reaches that of the photovoltaic grid-connected inverter; During off-grid operation, if the output power of the photovoltaic grid-connected inverter is less than the power of the important load, the household photovoltaic energy storage inverter will power the important load; if the output power of the photovoltaic grid-connected inverter is greater than the power of the important load, the photovoltaic grid-connected inverter will power the important load, and the household photovoltaic energy storage inverter will allocate excess power from the photovoltaic grid-connected inverter to charge the battery.

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