Photovoltaic energy storage inverter

Abstract

This utility model discloses a photovoltaic energy storage inverter, which includes a first battery connection port, a second battery connection port, a mains connection port, a load connection port, a photovoltaic module connection port, a first DC-DC conversion module, a second DC-DC conversion module, a DC-AC inverter module, a bus module, an MPPT module, a switching module, and a controller for controlling each module. The first battery connection port and the second connection port are connected to the first DC-DC conversion module and the second DC-DC conversion module through the switching module. The mains connection port and the load connection port are connected to the DC-AC inverter module. The photovoltaic module connection port is connected to the MPPT module. The MPPT module and the DC-AC inverter module are connected to the first DC-DC conversion module and the second DC-DC conversion module through the bus module. This utility model can be adapted to both high-voltage and low-voltage battery systems, and is flexible in use.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic energy storage, and in particular to a photovoltaic energy storage inverter. Background Technology

[0002] In existing photovoltaic energy storage systems, the energy storage inverter connects photovoltaic modules, energy storage batteries, and mains power. Typically, during the day, the photovoltaic modules generate electricity and charge the energy storage batteries through the energy storage inverter. At night, the energy storage batteries are inverted by the energy storage inverter to supply power to the loads. Alternatively, when the mains power fails, the energy storage inverter can operate off-grid to supply power to household loads.

[0003] Existing energy storage inverters are manufactured with a limited range of compatible energy storage batteries. This means that the inverter can only be connected to either a high-voltage battery system (which includes multiple energy storage batteries connected in series) or a low-voltage battery system (which includes multiple energy storage batteries connected in parallel). This limits its application and does not allow users to expand the total battery capacity.

[0004] In view of the above problems, it is necessary to study a photovoltaic energy storage inverter that can be adapted to both high-voltage and low-voltage battery systems and is flexible in use. Utility Model Content

[0005] The purpose of this invention is to provide a photovoltaic energy storage inverter that can be adapted to both high-voltage and low-voltage battery systems and is flexible in use.

[0006] To achieve the above objectives, the solution of this utility model is:

[0007] A photovoltaic energy storage inverter includes a first battery connection port, a second battery connection port, a mains connection port, a load connection port, a photovoltaic module connection port, a first DC-DC conversion module, a second DC-DC conversion module, a DC-AC inverter module, a bus module, an MPPT module, a switching module, and a controller. The first battery connection port and the second connection port are connected to the first DC-DC conversion module and the second DC-DC conversion module through the switching module. The mains connection port and the load connection port are connected to the DC-AC inverter module. The photovoltaic module connection port is connected to the MPPT module. The MPPT module and the DC-AC inverter... The module is connected to the first DC-DC conversion module and the second DC-DC conversion module via the bus module; the controller is connected to the first DC-DC conversion module, the second DC-DC conversion module, the DC-AC inverter module, the MPPT module and the switching module respectively. The switching module is used to control whether the first battery connection port is connected to the first DC-DC conversion module and the second DC-DC conversion module. The switching module also controls whether the second battery connection port is connected to the first DC-DC conversion module and the second DC-DC conversion module. The first DC-DC conversion module is adapted to the low-voltage battery system and the second DC-DC conversion module is adapted to the high-voltage battery system.

[0008] The switching module includes switches SW1, SW2, SW3, SW4, SW5, SW6, SW7, and SW8. The first conducting terminals of switches SW1 and SW2 are connected to the first switching terminal of the switching module; the first conducting terminals of switches SW3 and SW4 are connected to the second switching terminal of the switching module; the first conducting terminals of switches SW5 and SW6 are connected to the third switching terminal of the switching module; the first conducting terminals of switches SW7 and SW8 are connected to the fourth switching terminal of the switching module; the second conducting terminals of switches SW1 and SW3 are connected to the fifth switching terminal of the switching module; the second conducting terminals of switches SW2 and SW4 are connected to the sixth switching terminal of the switching module; and the second conducting terminals of switches SW5 and SW7 are connected to the seventh switching terminal of the switching module. Switch SW6... The second conducting terminal of switch SW1 and the second conducting terminal of switch SW8 are connected to the eighth switching terminal of the switching module; the enable terminals of switches SW1, SW2, SW3, SW4, SW5, SW6, SW7 and SW8 are connected to the controller; the first switching terminal of the switching module is connected to pin 1 of the first battery connection port, the second switching terminal of the switching module is connected to pin 1 of the second battery connection port, the third switching terminal of the switching module is connected to pin 2 of the second battery connection port, the fourth switching terminal of the switching module is connected to pin 2 of the first battery connection port, the fifth switching terminal of the switching module is connected to the first DC side positive terminal of the first DC-DC conversion module, the sixth switching terminal of the switching module is connected to the first DC side positive terminal of the second DC-DC conversion module, the seventh switching terminal of the switching module is connected to the first DC side negative terminal of the first DC-DC conversion module, and the eighth switching terminal of the switching module is connected to the first DC side negative terminal of the second DC-DC conversion module.

[0009] The first DC-DC conversion module is an isolated DC-DC converter.

[0010] The first DC-DC converter module includes transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8, a transformer T1, and capacitors C1 and C2. The source of transistor Q1, the source of transistor Q2, and the first terminal of capacitor C1 are connected to the positive terminal of the first DC side of the first DC-DC converter module. The drain of transistor Q3, the drain of transistor Q4, and the second terminal of capacitor C1 are connected to the negative terminal of the first DC side of the first DC-DC converter module. The drain of transistor Q1 and the source of transistor Q3 are connected to the first terminal of the primary winding of transformer T1. The drain of transistor Q2 and the source of transistor Q4 are connected to the second terminal of the primary winding of transformer T1. The first terminal of the secondary winding of transformer T1 is connected to capacitor C2. C2 connects to the drain of transistor Q5 and the source of transistor Q7. The second terminal of the secondary winding of transformer T1 connects to the drain of transistor Q6 and the source of transistor Q8. The sources of transistors Q5 and Q6 are connected to the positive terminal of the second DC side of the first DC-DC converter module. The drains of transistors Q7 and Q8 are connected to the negative terminal of the second DC side of the first DC-DC converter module. The gates of transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 are connected to the controller. The positive and negative terminals of the first DC side of the first DC-DC converter module are connected to the switching module. The positive and negative terminals of the second DC side of the first DC-DC converter module are connected to the bus module.

[0011] The second DC-DC conversion module uses a Buck-Boost converter.

[0012] The second DC-DC conversion module includes transistors Q9, Q10, Q11, and Q12, capacitor C4, and inductor L1. The source of transistor Q9 and the first terminal of capacitor C4 are connected to the first DC positive terminal of the second DC-DC conversion module. The drain of transistor Q9 is connected to the first terminal of inductor L1 and the source of transistor Q10. The second terminal of inductor L1 is connected to the drain of transistor Q12 and the source of transistor Q11. The source of transistor Q12 is connected to the second DC positive terminal of the second DC-DC conversion module. The drains of transistors Q10 and Q11 and the second terminal of capacitor C4 are connected to the first DC negative terminal and the second DC negative terminal of the second DC-DC conversion module. The gates of transistors Q9, Q10, Q11, and Q12 are connected to the controller. The first DC positive terminal and the first DC negative terminal of the second DC-DC conversion module are connected to the switching module. The second DC positive terminal and the second DC negative terminal of the second DC-DC conversion module are connected to the bus module.

[0013] The DC-AC inverter module includes transistors Q13, Q14, Q15, Q16, Q17, and Q18, capacitor C5, inductor L2, and inductor L3. The sources of transistors Q13 and Q14 are connected to the positive DC side of the DC-AC inverter module. The drains of transistors Q15 and Q16 are connected to the negative DC side of the DC-AC inverter module. The drains of transistors Q13 and Q15 are connected to the source of transistor Q17 and the first terminal of inductor L2. The drains of transistors Q14 and Q16 are connected to the source of transistor Q18 and the first terminal of inductor L3. The drain of transistor Q17 is connected to the transistor... The drain of transistor Q18, the second terminal of inductor L2, and the first terminal of capacitor C5 are connected to the AC live wire of the DC-AC inverter module. The second terminal of inductor L3 and the second terminal of capacitor C5 are connected to the AC neutral wire of the DC-AC inverter module. The gates of transistors Q13, Q14, Q15, Q16, Q17, and Q18 are connected to the controller. The DC positive and DC negative terminals of the DC-AC inverter module are connected to the bus module. The AC live wire of the DC-AC inverter module is connected to pin 1 of the mains connection port and pin 1 of the load connection port. The AC neutral wire of the DC-AC inverter module is connected to pin 2 of the mains connection port and pin 2 of the load connection port.

[0014] The MPPT module includes transistor Q19, diode D1, capacitor C6, capacitor C7, and inductor L4. The first terminals of capacitor C6 and inductor L4 are connected to the positive input terminal of the MPPT module. The second terminal of inductor L4 is connected to the positive terminal of diode D1 and the source terminal of transistor Q19. The negative terminal of diode D1 and the first terminal of capacitor C7 are connected to the positive output terminal of the MPPT module. The second terminals of capacitor C6 and C7 and the drain terminal of transistor Q19 are connected to the negative input terminal and the negative output terminal of the MPPT module. The gate terminal of transistor Q19 is connected to the controller. The positive and negative input terminals of the MPPT module are connected to pins 1 and 2 of the photovoltaic module connection port, respectively. The positive and negative output terminals of the MPPT module are connected to the bus module.

[0015] The bus module includes capacitor C3.

[0016] The controller uses a microcontroller.

[0017] With the above solution, when using the photovoltaic energy storage inverter of this invention, the first battery connection port and the second battery connection port are used to connect to the battery system (high-voltage battery system and low-voltage battery system), the mains connection port is used to connect to the mains power grid, the load connection port is used to connect to the load, and the photovoltaic module connection port is used to connect to the photovoltaic module. Since the switching module controls whether the first battery connection port is connected to the first DC-DC conversion module and the second DC-DC conversion module, and the switching module also controls whether the second battery connection port is connected to the first DC-DC conversion module and the second DC-DC conversion module, with the first DC-DC conversion module adapted to the low-voltage battery system and the second DC-DC conversion module adapted to the high-voltage battery system, the photovoltaic energy storage inverter of this invention can be used as follows:

[0018] When the first battery connection port is connected to a low-voltage battery system and the second battery connection port is not connected to a voltage system, the controller controls the switching module to connect the first battery connection port to the first DC-DC conversion module, and the first DC-DC conversion module charges and discharges the low-voltage battery system connected to the first battery connection port.

[0019] When the second battery connection port is connected to the low-voltage battery system and the first battery connection port is not connected to the voltage system, the controller controls the switching module to connect the second battery connection port to the first DC-DC conversion module, and the first DC-DC conversion module charges and discharges the low-voltage battery system connected to the second battery connection port.

[0020] When the first battery connection port is connected to the high-voltage battery system and the second battery connection port is not connected to the voltage system, the controller controls the switching module to connect the first battery connection port to the second DC-DC conversion module, and the second DC-DC conversion module charges and discharges the high-voltage battery system connected to the first battery connection port.

[0021] When the second battery connection port is connected to the high-voltage battery system and the first battery connection port is not connected to the voltage system, the controller controls the switching module to connect the second battery connection port to the second DC-DC conversion module, and the second DC-DC conversion module charges and discharges the high-voltage battery system connected to the second battery connection port.

[0022] When the first battery connection port is connected to the low-voltage battery system and the second battery connection port is connected to the low-voltage battery system, the controller controls the switching module to connect the first battery connection port and the second battery connection port to the first DC-DC conversion module, and the first DC-DC conversion module charges and discharges the low-voltage battery system connected to the first battery connection port and the low-voltage battery system connected to the second battery connection port.

[0023] When the first battery connection port is connected to the high-voltage battery system and the second battery connection port is connected to the high-voltage battery system, the controller controls the switching module to connect the first battery connection port and the second battery connection port to the second DC-DC conversion module, and the second DC-DC conversion module charges and discharges the high-voltage battery system connected to the first battery connection port and the high-voltage battery system connected to the second battery connection port.

[0024] When the first battery connection port is connected to the low-voltage battery system and the second battery connection port is connected to the high-voltage battery system, the controller controls the switching module to connect the first battery connection port to the first DC-DC conversion module and the second battery connection port to the second DC-DC conversion module. The first DC-DC conversion module charges and discharges the low-voltage battery system connected to the first battery connection port, and the second DC-DC conversion module charges and discharges the high-voltage battery system connected to the second battery connection port.

[0025] When the first battery connection port is connected to the high-voltage battery system and the second battery connection port is connected to the low-voltage battery system, the controller controls the switching module to connect the first battery connection port to the second DC-DC conversion module and the second battery connection port to the first DC-DC conversion module. The first DC-DC conversion module charges and discharges the low-voltage battery system connected to the second battery connection port, and the second DC-DC conversion module charges and discharges the high-voltage battery system connected to the first battery connection port.

[0026] As can be seen from the above, the photovoltaic energy storage inverter of this utility model can be adapted to both high-voltage and low-voltage battery systems, making it flexible in use and convenient for users to select between high-voltage and low-voltage battery systems. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the principle of this utility model.

[0028] Figure 2 The principle of the local circuit of this utility model Figure 1 .

[0029] Figure 3 The principle of the local circuit of this utility model Figure 2 .

[0030] Figure 4 The principle of the local circuit of this utility model Figure 3 . Detailed Implementation

[0031] To further explain the technical solution of this utility model, the following detailed description is provided through specific embodiments.

[0032] like Figures 1 to 4As shown, this utility model discloses a photovoltaic energy storage inverter, which includes a first battery connection port, a second battery connection port, a mains connection port, a load connection port, a photovoltaic module connection port, a first DC-DC conversion module, a second DC-DC conversion module, a DC-AC inverter module, a bus module, an MPPT module, a switching module, and a controller; wherein, the first battery connection port and the second connection port are connected to the first DC-DC conversion module and the second DC-DC conversion module through the switching module, the mains connection port and the load connection port are connected to the DC-AC inverter module, the photovoltaic module connection port is connected to the MPPT module, and the MPPT module and... The DC-AC inverter module is connected to the first DC-DC conversion module and the second DC-DC conversion module via a bus module. The controller is connected to the first DC-DC conversion module, the second DC-DC conversion module, the DC-AC inverter module, the MPPT module, and the switching module, respectively. The switching module is used to control whether the first battery connection port is connected to the first DC-DC conversion module and the second DC-DC conversion module. The switching module also controls whether the second battery connection port is connected to the first DC-DC conversion module and the second DC-DC conversion module. The first DC-DC conversion module is adapted to the low-voltage battery system, and the second DC-DC conversion module is adapted to the high-voltage battery system.

[0033] In use, the photovoltaic energy storage inverter of this invention has a first battery connection port and a second battery connection port for connecting to a battery system (high-voltage battery system and low-voltage battery system), a mains connection port for connecting to the mains power grid, a load connection port for connecting to a load, and a photovoltaic module connection port for connecting to a photovoltaic module. Since the switching module controls whether the first battery connection port is connected to the first DC-DC conversion module and the second DC-DC conversion module, and also controls whether the second battery connection port is connected to the first DC-DC conversion module and the second DC-DC conversion module, with the first DC-DC conversion module adapted to the low-voltage battery system and the second DC-DC conversion module adapted to the high-voltage battery system, the photovoltaic energy storage inverter of this invention can be used as follows:

[0034] When the first battery connection port is connected to the low-voltage battery system and the second battery connection port is not connected to the voltage system, the controller controls the switching module (controls the closing of the switches SW1 and SW7 below) so that the first battery connection port is connected to the first DC-DC conversion module, and the first DC-DC conversion module charges and discharges the low-voltage battery system connected to the first battery connection port.

[0035] When the second battery connection port is connected to the low-voltage battery system and the first battery connection port is not connected to the voltage system, the controller controls the switching module (controls the closing of the switches SW3 and SW5 below) so that the second battery connection port is connected to the first DC-DC conversion module, and the first DC-DC conversion module charges and discharges the low-voltage battery system connected to the second battery connection port.

[0036] When the first battery connection port is connected to the high-voltage battery system and the second battery connection port is not connected to the voltage system, the controller controls the switching module (controls the closing of the switches SW2 and SW8 below) so that the first battery connection port is connected to the second DC-DC conversion module, and the second DC-DC conversion module charges and discharges the high-voltage battery system connected to the first battery connection port.

[0037] When the second battery connection port is connected to the high-voltage battery system and the first battery connection port is not connected to the voltage system, the controller controls the switching module (controls the closing of the switches SW4 and SW6 below) so that the second battery connection port is connected to the second DC-DC conversion module, and the second DC-DC conversion module charges and discharges the high-voltage battery system connected to the second battery connection port.

[0038] When the first battery connection port is connected to the low-voltage battery system and the second battery connection port is connected to the low-voltage battery system, the controller controls the switching module (controls the closing of the switches SW1, SW3, SW5 and SW7 below) so that the first battery connection port and the second battery connection port are connected to the first DC-DC conversion module, and the first DC-DC conversion module charges and discharges the low-voltage battery system connected to the first battery connection port and the low-voltage battery system connected to the second battery connection port.

[0039] When the first battery connection port is connected to the high-voltage battery system and the second battery connection port is connected to the high-voltage battery system, the controller controls the switching module (controls the closing of the switches SW2, SW4, SW6 and SW8 below) so that the first battery connection port and the second battery connection port are connected to the second DC-DC conversion module, and the second DC-DC conversion module charges and discharges the high-voltage battery system connected to the first battery connection port and the high-voltage battery system connected to the second battery connection port.

[0040] When the first battery connection port is connected to the low-voltage battery system and the second battery connection port is connected to the high-voltage battery system, the controller controls the switching module (controls the closing of switches SW1, SW4, SW6 and SW7 below) so that the first battery connection port is connected to the first DC-DC conversion module and the second battery connection port is connected to the second DC-DC conversion module. The first DC-DC conversion module charges and discharges the low-voltage battery system connected to the first battery connection port, and the second DC-DC conversion module charges and discharges the high-voltage battery system connected to the second battery connection port.

[0041] When the first battery connection port is connected to the high-voltage battery system and the second battery connection port is connected to the low-voltage battery system, the controller controls the switching module (controls the closing of switches SW2, SW3, SW5 and SW8) so that the first battery connection port is connected to the second DC-DC conversion module and the second battery connection port is connected to the first DC-DC conversion module. The first DC-DC conversion module charges and discharges the low-voltage battery system connected to the second battery connection port, and the second DC-DC conversion module charges and discharges the high-voltage battery system connected to the first battery connection port.

[0042] As can be seen from the above, the photovoltaic energy storage inverter of this utility model can be adapted to both high-voltage and low-voltage battery systems, making it flexible in use and convenient for users to select between high-voltage and low-voltage battery systems.

[0043] In an embodiment of this utility model, the switching module includes switches SW1, SW2, SW3, SW4, SW5, SW6, SW7, and SW8. The first conducting terminals of switches SW1 and SW2 are connected to the first switching terminal of the switching module; the first conducting terminals of switches SW3 and SW4 are connected to the second switching terminal of the switching module; the first conducting terminals of switches SW5 and SW6 are connected to the third switching terminal of the switching module; the first conducting terminals of switches SW7 and SW8 are connected to the fourth switching terminal of the switching module; the second conducting terminals of switches SW1 and SW3 are connected to the fifth switching terminal of the switching module; and the second conducting terminal of switch SW2 is connected to the fourth switching terminal of the switching module. The second conducting terminal of SW4 is connected to the sixth switching terminal of the switching module; the second conducting terminals of SW5 and SW7 are connected to the seventh switching terminal of the switching module; and the second conducting terminals of SW6 and SW8 are connected to the eighth switching terminal of the switching module. The enable terminals of each of the switches SW1, SW2, SW3, SW4, SW5, SW6, SW7, and SW8 are connected to the controller. The controller controls the on / off state of switches SW1, SW2, SW3, SW4, SW5, SW6, SW7, and SW8. Switches SW1, SW2, SW3, SW4, SW5, SW6, SW7, and SW8 can be transistors. The first switching terminal of the switching module is connected to pin 1 of the first battery connection port, the second switching terminal of the switching module is connected to pin 1 of the second battery connection port, the third switching terminal of the switching module is connected to pin 2 of the second battery connection port, the fourth switching terminal of the switching module is connected to pin 2 of the first battery connection port, the fifth switching terminal of the switching module is connected to the first DC side positive terminal of the first DC-DC conversion module, the sixth switching terminal of the switching module is connected to the first DC side positive terminal of the second DC-DC conversion module, the seventh switching terminal of the switching module is connected to the first DC side negative terminal of the first DC-DC conversion module, and the eighth switching terminal of the switching module is connected to the first DC side negative terminal of the second DC-DC conversion module.

[0044] In this embodiment of the invention, the first DC-DC conversion module employs an isolated DC-DC converter. The isolated DC-DC converter provides isolation, allowing the use of transistors with low voltage withstand capability and low internal resistance on the low-voltage side, while high-voltage, low-current transistors can be used on the high-voltage side, thus adapting to low-voltage battery systems with high output current. Specifically, the first DC-DC conversion module includes transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8, a transformer T1, capacitors C1 and C2; the source of transistor Q1, transistor Q2... The source of transistor Q1 and the first terminal of capacitor C1 are connected to the positive terminal of the first DC-DC converter module. The drain of transistor Q3, the drain of transistor Q4, and the second terminal of capacitor C1 are connected to the negative terminal of the first DC-DC converter module. The drain of transistor Q1 and the source of transistor Q3 are connected to the first terminal of the primary winding of transformer T1. The drain of transistor Q2 and the source of transistor Q4 are connected to the second terminal of the primary winding of transformer T1. The first terminal of the secondary winding of transformer T1 is connected to the drain of transistor Q5 and the source of transistor Q7 through capacitor C2. The second terminal of the secondary winding of transformer T1 is connected to the transistor... The drain of transistor Q6 and the source of transistor Q8, and the sources of transistors Q5 and Q6 are connected to the positive terminal of the second DC side of the first DC-DC converter module. The drains of transistors Q7 and Q8 are connected to the negative terminal of the second DC side of the first DC-DC converter module. The gates of transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 are connected to the controller. The controller controls the switching of transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8. The conversion of DC voltage is achieved; the first DC-DC conversion module's first DC-DC positive and first DC-DC negative terminals are connected to the switching module, and the second DC-DC conversion module's second DC-DC positive and second DC-DC negative terminals are connected to the bus module; when the first DC-DC conversion module charges the low-voltage battery system, the first DC-DC conversion module's first DC-DC voltage can be lower than one-seventh of the first DC-DC conversion module's second DC-DC voltage; while when the low-voltage battery system discharges, the first DC-DC conversion module's first DC-DC voltage can be greater than one-seventh of the first DC-DC conversion module's second DC-DC voltage.

[0045] In this embodiment of the invention, the second DC-DC conversion module employs a Buck-Boost converter. Buck-Boost converters have a wide voltage range and are compatible with high-voltage battery systems. Specifically, the second DC-DC conversion module includes transistors Q9, Q10, Q11, and Q12, capacitor C4, and inductor L1. The source of transistor Q9 and the first terminal of capacitor C4 are connected to the positive terminal of the first DC side of the second DC-DC conversion module. The drain of transistor Q9 is connected to the first terminal of inductor L1 and the source of transistor Q10. The second terminal of inductor L1 is connected to the drain of transistor Q12 and the source of transistor Q11. The source of transistor Q12 is connected to... The second DC-DC converter module's second DC-DC positive terminal is connected to the second DC-DC positive terminal. The drains of transistors Q10 and Q11, and the second terminal of capacitor C4 are connected to the first and second DC-DC negative terminals of the second DC-DC converter module. The gates of transistors Q9, Q10, Q11, and Q12 are connected to the controller. The controller achieves DC voltage conversion by switching transistors Q9, Q10, Q11, and Q12. The first DC-DC positive and negative terminals of the second DC-DC converter module are connected to the switching module, and the second DC-DC positive and negative terminals are connected to the bus module. When the high-voltage battery system is discharging, if the voltage of the high-voltage battery system is greater than the maximum full-load operating voltage of the bus module, the controller controls transistor Q12 to be normally closed, transistor Q11 to be normally open, and transistors Q9 and Q10 to be complementaryly turned on, so that the second DC-DC converter module operates in discharge BUCK mode. When the high-voltage battery system is discharging, if the voltage of the high-voltage battery system is less than the maximum full-load operating voltage of the bus module, the controller controls transistors Q12 and Q11 to conduct complementaryly, transistors Q9 and Q10 to conduct complementaryly, and the duty cycles of transistors Q9, Q11, Q10, and Q12 are the same, causing the second DC-DC conversion module to operate in charging BOOST mode. When the high-voltage battery system is charging, if the voltage of the high-voltage battery system is greater than the maximum full-load operating voltage of the bus module, the controller controls transistor Q12 to be normally closed, transistor Q11 to be normally open, and transistors Q9 and Q10 to conduct complementaryly, causing the second DC-DC conversion module to operate in discharging BOOST mode. When the high-voltage battery system is charging, if the voltage of the high-voltage battery system is less than the maximum full-load operating voltage of the bus module, the controller controls transistors Q12 and Q11 to conduct complementaryly, transistors Q9 and Q10 to conduct complementaryly, and the duty cycles of transistors Q9, Q11, Q10, and Q12 are the same, causing the second DC-DC conversion module to operate in discharging BUCK mode.

[0046] In an embodiment of this utility model, the DC-AC inverter module includes transistors Q13, Q14, Q15, Q16, Q17, Q18, capacitor C5, inductor L2, and inductor L3; the source of transistor Q13 and the source of transistor Q14 are connected to the positive terminal of the DC-AC inverter module; the drain of transistor Q15 and the drain of transistor Q16 are connected to the negative terminal of the DC-AC inverter module; the drain of transistor Q13 and the source of transistor Q15 are connected to the source of transistor Q17 and the first terminal of inductor L2; the drain of transistor Q14 and the source of transistor Q16 are connected to the source of transistor Q18 and the first terminal of inductor L3; transistor Q17... The drain of transistor Q13 is connected to the drain of transistor Q18. The second end of inductor L2 and the first end of capacitor C5 are connected to the AC side live wire of the DC-AC inverter module. The second end of inductor L3 and the second end of capacitor C5 are connected to the AC side neutral wire of the DC-AC inverter module. The gates of transistors Q13, Q14, Q15, Q16, Q17, and Q18 are connected to the controller. The DC side positive and negative terminals of the DC-AC inverter module are connected to the bus module. The AC side live wire of the DC-AC inverter module is connected to pin 1 of the mains connection port and pin 1 of the load connection port. The AC side neutral wire of the DC-AC inverter module is connected to pin 2 of the mains connection port and pin 2 of the load connection port. During the half-cycle when the mains voltage is greater than zero, the controller closes transistors Q13 and Q16, and opens transistors Q14, Q15, Q17, and Q18. The current flow of the DC-AC inverter module is: bus module → transistor Q13 → inductor L2 → load → inductor L3 → transistor Q16 → bus module. During the freewheeling phase of the half-cycle when the mains voltage is greater than zero, the controller closes transistors Q17 and Q18, and opens transistors Q13, Q14, Q15, and Q16. Inductors L2 and L3 freewheel, and the current flow of the DC-AC inverter module is: inductor L2 → load → inductor L3 → transistor Q18 → transistor Q17 → inductor L2. During the half-cycle when the mains voltage is less than zero, and during the half-cycle when the mains voltage is greater than zero, the controller closes transistors Q14 and Q15, and opens transistors Q13, Q16, Q17, and Q18. The current flow of the DC-AC inverter module is: bus module → transistor Q14 → inductor L3 → load → inductor L2 → transistor Q15 → bus module. During the freewheeling phase of the half-cycle when the mains voltage is less than zero, the controller closes transistors Q17 and Q18, and opens transistors Q13, Q14, Q15, and Q16. Inductors L2 and L3 freewheel, and the current flow of the DC-AC inverter module is: inductor L3 → load → inductor L2 → transistor Q17 → transistor Q18 → inductor L3.

[0047] In an embodiment of this utility model, the MPPT module includes a transistor Q19, a diode D1, a capacitor C6, a capacitor C7, and an inductor L4. The first terminal of capacitor C6 and the first terminal of inductor L4 are connected to the positive input terminal of the MPPT module. The second terminal of inductor L4 is connected to the positive terminal of diode D1 and the source terminal of transistor Q19. The negative terminal of diode D1 and the first terminal of capacitor C7 are connected to the positive output terminal of the MPPT module. The second terminals of capacitor C6 and C7 and the drain terminal of transistor Q19 are connected to the negative input terminal and the negative output terminal of the MPPT module. The gate terminal of transistor Q19 is connected to the controller. The positive and negative input terminals of the MPPT module are respectively connected to pins 1 and 2 of the photovoltaic module connection port. The positive and negative output terminals of the MPPT module are connected to the bus module. When the voltage at the photovoltaic module connection port is greater than the set minimum voltage, the controller controls the MOSFET Q19 to switch. When the MOSFET Q19 is turned on, the inductor L4 starts charging, the diode D1 is reverse-biased and cut off, and the capacitor C7 discharges to the bus module. When the MOSFET Q19 is turned off, the inductor L4 discharges, the diode D1 is turned on, and the inductor L4 and the photovoltaic module connection port together charge the capacitor C7.

[0048] In an embodiment of this utility model, the bus module may include capacitor C3; the controller may be a microcontroller.

[0049] The above embodiments and figures are not intended to limit the product form and style of this utility model. Any appropriate changes or modifications made by those skilled in the art should be considered as not departing from the patent scope of this utility model.

Claims

1. A photovoltaic energy storage inverter, characterized in that: It includes a first battery connection port, a second battery connection port, a mains power connection port, a load connection port, a photovoltaic module connection port, a first DC-DC conversion module, a second DC-DC conversion module, a DC-AC inverter module, a bus module, an MPPT module, a switching module, and a controller; The first battery connection port and the second connection port are connected to the first DC-DC conversion module and the second DC-DC conversion module through a switching module. The mains connection port and the load connection port are connected to the DC-AC inverter module. The photovoltaic module connection port is connected to the MPPT module. The MPPT module and the DC-AC inverter module are connected to the first DC-DC conversion module and the second DC-DC conversion module through a bus module. The controller is connected to the first DC-DC conversion module, the second DC-DC conversion module, the DC-AC inverter module, the MPPT module, and the switching module respectively. The switching module is used to control whether the first battery connection port is connected to the first DC-DC conversion module and the second DC-DC conversion module. The switching module also controls whether the second battery connection port is connected to the first DC-DC conversion module and the second DC-DC conversion module. The first DC-DC conversion module is adapted to the low-voltage battery system, and the second DC-DC conversion module is adapted to the high-voltage battery system.

2. The photovoltaic energy storage inverter as described in claim 1, characterized in that: The switching module includes switches SW1, SW2, SW3, SW4, SW5, SW6, SW7, and SW8. The first conducting terminals of switches SW1 and SW2 are connected to the first switching terminal of the switching module; the first conducting terminals of switches SW3 and SW4 are connected to the second switching terminal of the switching module; the first conducting terminals of switches SW5 and SW6 are connected to the third switching terminal of the switching module; and the first conducting terminals of switches SW7 and SW8 are connected to the fourth switching terminal of the switching module. The second conducting terminals of switch SW1 and switch SW3 are connected to the fifth switching terminal of the switching module; the second conducting terminals of switch SW2 and switch SW4 are connected to the sixth switching terminal of the switching module; the second conducting terminals of switch SW5 and switch SW7 are connected to the seventh switching terminal of the switching module; and the second conducting terminals of switch SW6 and switch SW8 are connected to the eighth switching terminal of the switching module. The enable terminals of switches SW1, SW2, SW3, SW4, SW5, SW6, SW7, and SW8 are each connected to the controller. The first switching terminal of the switching module is connected to pin 1 of the first battery connection port; the second switching terminal of the switching module is connected to pin 1 of the second battery connection port; the third switching terminal of the switching module is connected to pin 2 of the second battery connection port; the fourth switching terminal of the switching module is connected to pin 2 of the first battery connection port; the fifth switching terminal of the switching module is connected to the positive terminal of the first DC side of the first DC-DC conversion module; the sixth switching terminal of the switching module is connected to the positive terminal of the first DC side of the second DC-DC conversion module; the seventh switching terminal of the switching module is connected to the negative terminal of the first DC side of the first DC-DC conversion module; and the eighth switching terminal of the switching module is connected to the negative terminal of the first DC side of the second DC-DC conversion module.

3. The photovoltaic energy storage inverter as described in claim 1 or 2, characterized in that: The first DC-DC conversion module is an isolated DC-DC converter.

4. The photovoltaic energy storage inverter as described in claim 3, characterized in that: The first DC-DC conversion module includes transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, transformer T1, capacitor C1, and capacitor C2. The source of transistor Q1, the source of transistor Q2, and the first terminal of capacitor C1 are connected to the positive terminal of the first DC-DC converter module. The drain of transistor Q3, the drain of transistor Q4, and the second terminal of capacitor C1 are connected to the negative terminal of the first DC-DC converter module. The drain of transistor Q1 and the source of transistor Q3 are connected to the first terminal of the primary winding of transformer T1. The drain of transistor Q2 and the source of transistor Q4 are connected to the second terminal of the primary winding of transformer T1. The first terminal of the secondary winding of transformer T1 is connected to the transistor via capacitor C2. The drain of transistor Q5 and the source of transistor Q7 are connected to the drain of transistor Q6 and the source of transistor Q8 via the second terminal of the secondary winding of transformer T1. The sources of transistors Q5 and Q6 are connected to the positive terminal of the second DC side of the first DC-DC conversion module, and the drains of transistors Q7 and Q8 are connected to the negative terminal of the second DC side of the first DC-DC conversion module. The gates of transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 are each connected to the controller. The first DC-DC converter module's positive and negative DC terminals are connected to a switching module, and the second DC-DC converter module's positive and negative DC terminals are connected to a bus module.

5. The photovoltaic energy storage inverter as described in claim 1 or 2, characterized in that: The second DC-DC conversion module uses a Buck-Boost converter.

6. The photovoltaic energy storage inverter as described in claim 5, characterized in that: The second DC-DC conversion module includes transistors Q9, Q10, Q11, and Q12, capacitor C4, and inductor L1. The source of transistor Q9 and the first terminal of capacitor C4 are connected to the first DC positive terminal of the second DC-DC conversion module. The drain of transistor Q9 is connected to the first terminal of inductor L1 and the source of transistor Q10. The second terminal of inductor L1 is connected to the drain of transistor Q12 and the source of transistor Q11. The source of transistor Q12 is connected to the second DC positive terminal of the second DC conversion module. The drains of transistors Q10 and Q11 and the second terminal of capacitor C4 are connected to the first DC negative terminal and the second DC negative terminal of the second DC conversion module. The gates of transistors Q9, Q10, Q11, and Q12 are connected to the controller. The first DC-DC positive terminal and the first DC-DC negative terminal of the second DC-DC conversion module are connected to the switching module, and the second DC-DC positive terminal and the second DC-DC negative terminal of the second DC-DC conversion module are connected to the bus module.

7. The photovoltaic energy storage inverter as described in claim 1, characterized in that: The DC-AC inverter module includes transistors Q13, Q14, Q15, Q16, Q17, and Q18, capacitor C5, inductor L2, and inductor L3. The sources of transistors Q13 and Q14 are connected to the positive DC side of the DC-AC inverter module. The drains of transistors Q15 and Q16 are connected to the negative DC side of the DC-AC inverter module. The drains of transistors Q13 and Q15 are connected to the source of transistor Q17 and the first terminal of inductor L2. The drains of transistors Q14 and Q16 are connected to the source of transistor Q18 and the first terminal of inductor L3. The drain of transistor Q17 is connected to the transistor... The drain of transistor Q18, the second terminal of inductor L2, and the first terminal of capacitor C5 are connected to the AC live wire of the DC-AC inverter module. The second terminal of inductor L3 and the second terminal of capacitor C5 are connected to the AC neutral wire of the DC-AC inverter module. The gates of transistors Q13, Q14, Q15, Q16, Q17, and Q18 are connected to the controller. The DC positive and DC negative terminals of the DC-AC inverter module are connected to the bus module. The AC live wire of the DC-AC inverter module is connected to pin 1 of the mains connection port and pin 1 of the load connection port. The AC neutral wire of the DC-AC inverter module is connected to pin 2 of the mains connection port and pin 2 of the load connection port.

8. The photovoltaic energy storage inverter as described in claim 1, characterized in that: The MPPT module includes transistor Q19, diode D1, capacitor C6, capacitor C7, and inductor L4. The first terminal of capacitor C6 and the first terminal of inductor L4 are connected to the positive input terminal of the MPPT module. The second terminal of inductor L4 is connected to the positive terminal of diode D1 and the source terminal of transistor Q19. The negative terminal of diode D1 and the first terminal of capacitor C7 are connected to the positive output terminal of the MPPT module. The second terminals of capacitor C6 and C7 and the drain terminal of transistor Q19 are connected to the negative input terminal and the negative output terminal of the MPPT module. The gate of transistor Q19 is connected to the controller. The positive and negative input terminals of the MPPT module are connected to pins 1 and 2 of the photovoltaic module's connection port, respectively, and the positive and negative output terminals of the MPPT module are connected to the bus module.

9. The photovoltaic energy storage inverter as described in claim 1, characterized in that: The bus module includes capacitor C3.

10. The photovoltaic energy storage inverter as described in claim 1, characterized in that: The controller uses a microcontroller.

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