Photovoltaic system

Abstract

A photovoltaic system, relating to the field of power conversion devices. The photovoltaic system comprises: a photovoltaic module (12), which is used for supplying power to an energy storage module (11) and / or an inverter circuit (21); the energy storage module (11), which is used for receiving the power that is output by the photovoltaic module (12), or supplying power to the inverter circuit (21) when the photovoltaic module (12) does not operate; and the inverter circuit (21), which is used for inverting to a power grid the power supplied by the photovoltaic module (12) and / or the energy storage module (11). The photovoltaic module (12) and the energy storage module (11) can be directly connected to the inverter circuit (21), thereby preventing the loss caused by the conversion of a direct current-direct current module during the power exchange between the photovoltaic module (12) and the energy storage module (11). In addition, the power exchange between the photovoltaic module (12) and the energy storage module (11) is completed on a low-voltage side, thereby ensuring better safety.

Description

A photovoltaic system

[0001] This application claims priority to the Chinese patent application filed with the Patent Office of China on August 2, 2023, with application number 202310966869.0 and invention name “A Photovoltaic System”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of power conversion equipment, and in particular to a photovoltaic system. Background Art

[0003] In photovoltaic and energy storage systems, DC-DC modules and DC-AC modules are two key components. These two modules are connected via a DC bus. The PV panels are connected to the DC-DC modules, and the battery module output is also connected to the DC bus. When power is exchanged between the PV panels and the battery modules, it needs to be converted through the DC-DC module, which results in certain losses and lower power conversion efficiency. Furthermore, the high voltage on the DC bus reduces safety. Therefore, while the DC-DC module in existing technologies provides power exchange, it also presents efficiency and safety issues.

[0004] Summary of the Invention

[0005] The purpose of this application is to provide a photovoltaic system in which photovoltaic components and energy storage modules can be directly connected to the inverter circuit, avoiding the loss caused by the conversion of the DC-DC module when the photovoltaic components and the energy storage module interact with each other. In addition, the power interaction between the photovoltaic components and the energy storage module is completed on the low-voltage side, which is safer.

[0006] To solve the above technical problems, the present application provides a photovoltaic system, comprising:

[0007] Photovoltaic components, used to provide power to the energy storage module and / or the inverter circuit;

[0008] An energy storage module, the output end of which is connected to the output end of the photovoltaic module, and is used to receive the power output by the photovoltaic module, or to provide power to the inverter circuit when the photovoltaic module is not working;

[0009] The inverter circuit has an input end connected to the output end of the photovoltaic component and the output end of the energy storage module, and is used to invert the power provided by the photovoltaic component and / or the energy storage module to the power grid.

[0010] In one embodiment, the photovoltaic component is provided with a backflow current threshold voltage, and the energy storage module is specifically used to receive the power output by the photovoltaic component, or to provide the inverter circuit with a voltage less than the backflow current threshold voltage when the photovoltaic component is not working.

[0011] In one embodiment, it further includes:

[0012] A protection switch, one end of which is connected to the output end of the photovoltaic component, and the other end of which is connected to the output end of the energy storage module and the input end of the inverter circuit, is used to disconnect when the photovoltaic component is not working and the energy storage module provides power to the inverter circuit.

[0013] In one embodiment, the protection switch is specifically configured to receive a control instruction when the photovoltaic assembly is not working and the energy storage module provides power to the inverter circuit, and disconnect itself according to the control instruction.

[0014] In one embodiment, the protection switch is a relay, a MOS tube, or a contactor.

[0015] In one embodiment, it further includes:

[0016] a first auxiliary power supply, one end of which is connected to the output end of the photovoltaic module and the other end of which is connected to the power supply end of the protection switch, and is used to convert the output voltage of the photovoltaic module into a first preset voltage to power the protection switch;

[0017] When the photovoltaic assembly is not working, the voltage output by the first auxiliary power supply is lower than the first preset voltage, and the protection switch is disconnected.

[0018] In one embodiment, it further includes:

[0019] A second auxiliary power supply, one end of which is connected to the output end of the photovoltaic component and the output end of the energy storage module, and the other end of which is connected to the power supply end of the inverter circuit, is used to convert the output voltage of the photovoltaic component and / or the energy storage module into the second preset voltage to power each unit in the inverter circuit.

[0020] In one embodiment, it further includes:

[0021] A maximum power point tracking (MPPT) module has an input end connected to the output end of the photovoltaic module and a first output end connected to the control end of the inverter circuit. The module is used to detect the output power of the photovoltaic module and perform maximum power point tracking based on the output power to control the operation of the switch tube in the inverter circuit.

[0022] In one embodiment, the MPPT module further includes a second output terminal, and the second output terminal is connected to the control terminal of the energy storage module;

[0023] The MPPT module is also used to determine whether the output power of the photovoltaic component exceeds the maximum power set by the inverter circuit. If it does, the switch tube in the inverter circuit is controlled to operate in the maximum power state, and the switch tube in the energy storage module is controlled according to the difference between the output power and the maximum power.

[0024] In one embodiment, the MPPT module includes:

[0025] a current sampling circuit, connected to the output end of the photovoltaic module, for collecting the output current of the photovoltaic module;

[0026] A voltage sampling circuit is connected to the output terminal of the photovoltaic module and is used to collect the output voltage of the photovoltaic module;

[0027] A calculation module, wherein the input end is respectively connected to the output end of the current sampling circuit and the output end of the voltage sampling circuit, and the output end is respectively connected to the control end of the inverter circuit and the control end of the energy storage module, and is used to calculate the output power according to the output current and the output voltage, and output a control signal to the inverter circuit and / or the energy storage module according to the output power and the maximum power set by the inverter circuit, so as to control the operation of the switch tube in the inverter circuit and / or the switch tube in the energy storage module.

[0028] The present application provides a photovoltaic system, which relates to the field of power conversion equipment. The system includes a photovoltaic module for providing power to an energy storage module and / or an inverter circuit; an energy storage module for receiving power output by the photovoltaic module, or providing power to the inverter circuit when the photovoltaic module is not working; and an inverter circuit for inverting the power provided by the photovoltaic module and / or the energy storage module to the grid. In the present application, the photovoltaic module and the energy storage module can be directly connected to the inverter circuit, avoiding losses caused by the conversion of the DC-DC module when the photovoltaic module and the energy storage module interact with each other. In addition, the power interaction between the photovoltaic module and the energy storage module is completed on the low-voltage side, which is safer. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the prior art and the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] FIG1 is a structural block diagram of a photovoltaic system in the prior art;

[0031] FIG2 is a structural block diagram of a first photovoltaic system provided by this application;

[0032] FIG3 is a structural block diagram of a second photovoltaic system provided by this application;

[0033] FIG4 is a structural block diagram of a third photovoltaic system provided by this application;

[0034] FIG5 is a structural block diagram of a fourth photovoltaic system provided by this application;

[0035] FIG6 is a structural block diagram of a fifth photovoltaic system provided by this application;

[0036] FIG7 is a flow chart of a photovoltaic system provided by the present application;

[0037] FIG8 is an expanded schematic diagram of a photovoltaic system provided by the present application;

[0038] FIG9 is an expanded schematic diagram of another photovoltaic system provided in this application. DETAILED DESCRIPTION

[0039] The core of this application is to provide a photovoltaic system in which photovoltaic components and energy storage modules can be directly connected to the inverter circuit, avoiding the loss caused by the conversion of DC-DC modules when the photovoltaic components and energy storage modules interact with each other. In addition, the power interaction between the photovoltaic components and the energy storage modules is completed on the low-voltage side, which is safer.

[0040] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0041] As shown in FIG1 , in the prior art, although the DC-DC module 13 provides a power supply interaction function, it also has problems in terms of efficiency and safety.

[0042] To solve the above technical problems, the present application provides a photovoltaic system, as shown in FIG2 , comprising:

[0043] The photovoltaic assembly 12 is used to provide power to the energy storage module 11 and / or the inverter circuit 21;

[0044] The energy storage module 11 has an output end connected to the output end of the photovoltaic module 12, and is used to receive the power output by the photovoltaic module 12, or to provide power to the inverter circuit 21 when the photovoltaic module 12 is not working;

[0045] The inverter circuit 21 has an input end connected to the output end of the photovoltaic assembly 12 and the output end of the energy storage module 11 , and is used to invert the power provided by the photovoltaic assembly 12 and / or the energy storage module 11 to the grid.

[0046] This embodiment describes a photovoltaic system designed to address the efficiency and safety issues associated with DC-DC modules 13 in the prior art. The photovoltaic system includes the following components: A photovoltaic module 12 is a device used to convert solar energy into electrical energy, providing power to an energy storage module 11 and / or an inverter circuit 21. The output of the photovoltaic module 12 is connected to the output of the energy storage module 11, allowing the power output from the photovoltaic module 12 to be directly transmitted to the energy storage module 11. The energy storage module 11 is a device used to store electrical energy, and its output is connected to the photovoltaic module 12 and the inverter circuit 21. When the photovoltaic module 12 is operating, the energy storage module 11 receives and stores the power output from the photovoltaic module 12. When the photovoltaic module 12 is not operating, the energy storage module 11 provides power to the inverter circuit 21. This allows the energy storage module 11 to continue to provide power to the inverter circuit 21 even when there is no solar energy available. The inverter circuit 21 is a device used to convert DC power into AC power. The input end is connected to the output end of the photovoltaic component 12 and the output end of the energy storage module 11, and the inverter circuit 21 can convert the DC power provided by the photovoltaic component 12 and / or the energy storage module 11 into the AC power required by the power grid. The energy storage module 11 may include, but is not limited to, a battery 31 (or other forms of energy storage equipment) and a battery charge and discharge module 32 (as shown in Figure 3). In addition, the energy storage module 11 can also be a supercapacitor or other device with storage capacity. The inverter circuit 21 can include only a DC-AC module 14, or it can include a DC-DC module 13 and a DC-AC module 14. The core idea of ​​the photovoltaic system is to directly connect the power sources of the photovoltaic component 12 and the energy storage module 11 to the inverter circuit 21, thereby avoiding the conversion loss and safety issues introduced by the traditional DC-DC module 13.

[0047] The specific operating principle is as follows: PV panels 12 generate DC power, which is connected to energy storage module 11 through its output terminals. Energy storage module 11 stores the DC power provided by PV panels 12 and connects it to inverter circuit 21 through its output terminals when PV panels 12 are not operating. When PV panels 12 are not operating, inverter circuit 21 can continue to operate using the power provided by energy storage module 11, converting this power into AC power suitable for grid use.

[0048] This configuration of the photovoltaic system improves the efficiency of power conversion and avoids the conversion loss caused by the traditional DC-DC module 13; improves the safety of the system and avoids the safety hazards caused by the high voltage on the DC bus; the system has a certain energy storage function and can continue to provide power to the inverter circuit 21 when the photovoltaic module 12 is not working, thereby increasing the reliability of the system.

[0049] In summary, this embodiment proposes an innovative photovoltaic system configuration, which solves the efficiency and safety issues of the traditional DC-DC module 13 by directly connecting the photovoltaic components 12 and the energy storage module 11 to the inverter circuit 21, and improves the overall performance of the photovoltaic system.

[0050] In one embodiment, the photovoltaic assembly 12 is provided with a backflow current threshold voltage, and the energy storage module 11 is specifically used to receive the power output by the photovoltaic assembly 12, or to provide a voltage less than the backflow current threshold voltage to the inverter circuit 21 when the photovoltaic assembly 12 is not working.

[0051] Backflow current refers to the backflow of current from the battery 31 or other energy source to the photovoltaic module 12 when the photovoltaic module 12 is not working, causing energy loss and system instability.

[0052] To prevent the current output by the energy storage module 11 from flowing back into the photovoltaic panel 12, the photovoltaic panel 12 is provided with a backflow current threshold voltage. By setting the backflow current threshold voltage, the energy storage module 11 can provide a voltage lower than this voltage, thereby preventing the occurrence of backflow current. In this way, when the photovoltaic panel 12 is not operating, the energy storage module 11 can safely provide power to the inverter circuit 21, ensuring the normal operation of the photovoltaic system.

[0053] This photovoltaic system design effectively utilizes the electrical energy of the photovoltaic panels 12 and stores it in the energy storage module 11. Furthermore, when the photovoltaic panels 12 are not operating, the energy storage module 11 can continue to provide a continuous power source for the inverter circuit 21. This improves the efficiency and reliability of the photovoltaic system while reducing energy loss and safety risks.

[0054] As shown in FIG4 , in one embodiment, the method further includes:

[0055] The protection switch 41 has one end connected to the output end of the photovoltaic component 12 and the other end connected to the output end of the energy storage module 11 and the input end of the inverter circuit 21. It is used to disconnect when the photovoltaic component 12 is not working and the energy storage module 11 provides power to the inverter circuit 21.

[0056] To ensure system safety, this embodiment also includes a protection switch 41. One end of the protection switch 41 is connected to the output of the PV panel 12, and the other end is connected to the output of the energy storage module 11 and the input of the inverter circuit 21. When the PV panel 12 is not operating and the energy storage module 11 is providing power to the inverter circuit 21, the protection switch 41 disconnects, preventing the current output by the energy storage module 11 from flowing back into the PV panel 12, thus ensuring system safety.

[0057] In summary, the photovoltaic system described in this embodiment employs technology that directly converts the DC power from the photovoltaic panels 12 and energy storage modules 11 into AC power for the inverter circuit 21. This system effectively utilizes, converts, and connects photovoltaic energy to the power grid, achieving efficient energy conversion and utilization. Furthermore, the introduction of the protective switch 41 further enhances system safety.

[0058] In one embodiment, the protection switch 41 is specifically configured to receive a control instruction when the photovoltaic assembly 12 is not working and the energy storage module 11 provides power to the inverter circuit 21 , and disconnect itself according to the control instruction.

[0059] This embodiment further describes the protection switch 41 of the photovoltaic system. The protection switch 41 is configured to be disconnected under certain conditions to protect the inverter circuit 21 and the energy storage module 11.

[0060] Specifically, it has been described in the above embodiment that one end of the protection switch 41 is connected to the output end of the photovoltaic component 12, and the other end is connected to the output end of the energy storage module 11 and the input end of the inverter circuit 21. When the photovoltaic component 12 is not working and the energy storage module 11 provides power to the inverter circuit 21, the protection switch 41 serves to disconnect the circuit. Specifically, the protection switch 41 is able to receive control instructions and disconnect itself according to the control instructions. Specifically, when the photovoltaic component 12 is not working, it means that the photovoltaic component 12 cannot provide power. At this time, if the energy storage module 11 still provides power to the inverter circuit 21, it may cause safety problems of current backflow or damage to the equipment. Therefore, by disconnecting the protection switch 41 through control instructions, the circuit connection between the photovoltaic component 12 and the energy storage module 11 can be cut off to ensure the safety of the system.

[0061] Through the disconnection operation of the protection switch 41, the system can automatically switch to the working mode in which the energy storage module 11 provides power to the inverter circuit 21 when the photovoltaic component 12 is not working, and the protection switch 41 can be controlled according to the real-time situation to provide safer and more reliable system operation.

[0062] In one embodiment, the protection switch 41 is a relay, a MOS (Metal-Oxide-Semiconductor Field-Effect Transistor), or a contactor.

[0063] Specifically, in this embodiment, the protection switch 41 is described as a relay, a MOS tube, or a contactor. A relay is an electronic switch that can switch the on / off state of a circuit when it receives a control signal. A MOS tube is a semiconductor device that controls the on / off state of the MOS tube by changing the gate voltage, thereby achieving switching regulation of the circuit. MOS tubes have the advantages of fast response speed, high control accuracy, and low power consumption, and are suitable for scenarios requiring switching and regulation in photovoltaic systems. A contactor is a high-power switch that is realized by electromagnetic mechanical force and can be used to control and protect high-current circuits in photovoltaic systems. It is suitable for various environmental conditions and load types and has the characteristics of good durability, stability and reliability. In addition, the protection switch 41 can also be other devices that can control disconnection.

[0064] In this photovoltaic system, the function of the relay or MOS tube or contactor is to disconnect the circuit when the photovoltaic module 12 is not working and the energy storage module 11 provides power to the inverter circuit 21. The protection switch 41 is designed to prevent the current output by the energy storage module 11 from flowing back into the photovoltaic module 12. Backflow current refers to the current flowing from the battery (energy storage module 11) through the DC-DC module 13 to the photovoltaic module 12. Since the photovoltaic module 12 is designed to receive input from solar energy, it does not have the ability to handle backflow current. Therefore, when the energy storage module 11 provides power to the inverter circuit 21, it is necessary to disconnect the connection between the photovoltaic module 12 and the energy storage module 11 to avoid backflow current.

[0065] In practice, protection switch 41, acting as a relay, MOSFET, or contactor, can disconnect the circuit by receiving control instructions. These instructions can come from a system controller or other logic circuitry, which monitors the operating status of PV panels 12 and determines whether to disconnect the circuit. Once protection switch 41 receives the disconnect instruction, its internal electromagnetic relay, MOSFET, or contactor switches to the disconnected state, severing the connection between PV panels 12 and energy storage modules 11.

[0066] By using a relay, MOS tube, or contactor as a protective switch 41, a fast and reliable circuit disconnection function can be achieved. Relays and contactors can withstand high currents and voltages, making them suitable for the high-voltage DC bus environment found in photovoltaic systems. Furthermore, relays operate based on electromagnetic attraction and release, resulting in low power consumption and a long lifespan.

[0067] As shown in FIG4 , in one embodiment, the method further includes:

[0068] A first auxiliary power supply 42, one end of which is connected to the output end of the photovoltaic assembly 12 and the other end of which is connected to the power supply end of the protection switch 41, and is used to convert the output voltage of the photovoltaic assembly 12 into a first preset voltage to power the protection switch 41;

[0069] When the photovoltaic assembly 12 is not working, the voltage output by the first auxiliary power supply 42 is lower than the first preset voltage, and the protection switch 41 is disconnected.

[0070] In this embodiment, the photovoltaic system further includes a first auxiliary power supply 42. One end of the first auxiliary power supply 42 is connected to the output terminal of the photovoltaic assembly 12, and the other end is connected to the power supply terminal of the protection switch 41. The function of the first auxiliary power supply 42 is to convert the output voltage of the photovoltaic assembly 12 into a specified first preset voltage to power the protection switch 41. When the photovoltaic assembly 12 is not operating, that is, when it is not generating an output voltage, the output voltage of the first auxiliary power supply 42 will be less than the first preset voltage, which will cause the protection switch 41 to disconnect.

[0071] When the photovoltaic panel 12 is not operating and the energy storage module 11 is providing power to the inverter circuit 21, the protective switch 41 disconnects the circuit. In this case, the protective switch 41 receives a control instruction and disconnects itself accordingly. This prevents the current output by the energy storage module 11 from flowing back into the photovoltaic panel 12, thereby ensuring the normal operation and safety of the system.

[0072] In summary, the combination of the first auxiliary power supply 42 and the protection switch 41 described in this embodiment can prevent the current output by the energy storage module 11 from flowing back into the photovoltaic assembly 12 by disconnecting the protection switch 41 when the photovoltaic assembly 12 is not operating. This can improve the efficiency and safety of the system.

[0073] As shown in FIG5 , in one embodiment, the method further includes:

[0074] The second auxiliary power supply 43 has one end connected to the output end of the photovoltaic component 12 and the output end of the energy storage module 11, and the other end connected to the power supply end of the inverter circuit 21, and is used to convert the output voltage of the photovoltaic component 12 and / or the energy storage module 11 into a second preset voltage to power each unit in the inverter circuit 21.

[0075] In this embodiment, the second auxiliary power supply 43 is connected to the output terminals of the photovoltaic panel 12 and the energy storage module 11, and converts their output voltages into a second preset voltage to supply the various units in the inverter circuit 21. The function of the second auxiliary power supply 43 is to provide power to the inverter circuit 21 to ensure its normal operation. In a photovoltaic system, the second auxiliary power supply 43 needs to have voltage conversion capabilities. It can convert the output voltages of the photovoltaic panel 12 and the energy storage module 11 into the second preset voltage required by the inverter circuit 21. In this way, regardless of the output voltage of the photovoltaic panel 12 or the energy storage module 11, the second auxiliary power supply 43 can convert it into a voltage suitable for the inverter circuit 21.

[0076] The second auxiliary power supply 43 in this embodiment is a crucial component of the photovoltaic system. It converts the output voltage of the photovoltaic panels 12 and the energy storage module 11 into the voltage required by the inverter circuit 21, providing a stable power source for the inverter circuit 21. This design improves the reliability of the photovoltaic system and the operating efficiency of the inverter circuit 21.

[0077] As shown in FIG6 , in one embodiment, the method further includes:

[0078] The MPPT (Maximum Power Point Tracking) module has an input end connected to the output end of the photovoltaic module 12 and a first output end connected to the control end of the inverter circuit 21. It is used to detect the output power of the photovoltaic module 12 and perform maximum power point tracking based on the output power to control the operation of the switch tube in the inverter circuit 21.

[0079] This embodiment further describes another feature of the photovoltaic system, namely the presence and function of a maximum power point tracking (MPPT) module. The MPPT module's input terminal is connected to the output terminal of the photovoltaic module 12, and its first output terminal is connected to the control terminal of the inverter circuit 21. First, the MPPT module's purpose is to detect the output power of the photovoltaic module 12 and perform maximum power point tracking based on the output power. This means that the MPPT module is able to monitor the output of the photovoltaic module 12 and determine the optimal operating point to ensure that the photovoltaic module 12 operates at maximum efficiency. Through maximum power point tracking, the MPPT module can optimize the power output of the photovoltaic module 12. Secondly, this embodiment also involves controlling the operation of the switching tubes in the inverter circuit 21. The function of the inverter circuit 21 is to invert the power provided by the photovoltaic module 12 and / or the energy storage module 11 into the power required by the power grid. By connecting to the control terminal of the inverter circuit 21, the MPPT module can adjust the operation of the inverter circuit 21 by controlling the operation of the switching tubes to achieve control of the power grid output.

[0080] In summary, this embodiment provides a method for improving photovoltaic system efficiency and controlling grid output. By using the maximum power point tracking module, the system can fully utilize the output energy of the photovoltaic panels 12 and optimize grid output by controlling the inverter circuit 21. This helps improve the energy utilization rate and overall performance of the photovoltaic system.

[0081] In one embodiment, the MPPT module further includes a second output terminal and the second output terminal is connected to the control terminal of the energy storage module 11;

[0082] The MPPT module is also used to determine whether the output power of the photovoltaic component 12 exceeds the maximum power set by the inverter circuit 21. If it is greater, the switch tube in the inverter circuit 21 is controlled to operate at the maximum power state, and the switch tube in the energy storage module 11 is controlled according to the difference between the output power and the maximum power.

[0083] This embodiment further details the functions and effects of the maximum power point tracking (MPPT) module. First, the second output terminal of the MPPT module is connected to the control terminal of the energy storage module 11. This means that the MPPT module is responsible for controlling not only the switches in the inverter circuit 21 but also the operation of the switches in the energy storage module 11. Second, the MPPT module is also used to determine whether the output power of the photovoltaic module 12 exceeds the maximum power set by the inverter circuit 21. The purpose of maximum power point tracking is to ensure that the power output of the photovoltaic module 12 reaches its maximum value, thereby improving the efficiency and production capacity of the system. If the output power of the photovoltaic module 12 exceeds the maximum power set by the inverter circuit 21, the MPPT module will control the switches in the inverter circuit 21 to operate at maximum power to ensure that the power output of the photovoltaic module 12 is maximized. Finally, the MPPT module adjusts the output power of the photovoltaic module 12 by controlling the operation of the switches in the energy storage module 11 based on the difference between the output power of the photovoltaic module 12 and the maximum power. This means that the output power of the energy storage module 11 can be dynamically adjusted based on fluctuations in the output power of the photovoltaic module 12 to maintain system stability and efficiency.

[0084] In summary, this embodiment describes the functions and effects of the MPPT module, including controlling the operation of the switches in the inverter circuit 21 and the energy storage module 11, determining whether the output power of the photovoltaic module 12 exceeds the maximum power, and making corresponding adjustments. This design can maximize the efficiency and production capacity of the photovoltaic system while ensuring system stability.

[0085] As shown in FIG6 , in one embodiment, the MPPT module includes:

[0086] A current sampling circuit is connected to the output end of the photovoltaic module 12 and is used to collect the output current of the photovoltaic module 12;

[0087] A voltage sampling circuit is connected to the output terminal of the photovoltaic module 12 and is used to collect the output voltage of the photovoltaic module 12;

[0088] A calculation module, whose input end is respectively connected to the output end of the current sampling circuit and the voltage sampling circuit, and whose output end is respectively connected to the control end of the inverter circuit 21 and the control end of the energy storage module 11, is used to calculate the output power according to the output current and the output voltage, and output a control signal to the inverter circuit 21 and / or the energy storage module 11 according to the output power and the maximum power set by the inverter circuit 21, so as to control the operation of the switch tube in the inverter circuit 21 and / or the switch tube in the energy storage module 11.

[0089] This embodiment further describes an MPPT module in a photovoltaic system with a maximum power point tracking (MPPT) function. The MPPT module calculates the output power of the photovoltaic assembly 12 by collecting the output current and output voltage of the photovoltaic assembly 12. Based on the difference between the output power and the maximum power set by the inverter circuit 21, the module outputs a control signal to the inverter circuit 21 and / or the energy storage module 11, thereby controlling the operation of the switches in the inverter circuit 21 and / or the switches in the energy storage module 11.

[0090] Specifically, an embodiment of the MPPT module includes the following parts: a current sampling circuit: connected to the output end of the photovoltaic module 12, for collecting the output current of the photovoltaic module 12. A voltage sampling circuit: connected to the output end of the photovoltaic module 12, for collecting the output voltage of the photovoltaic module 12. A calculation module: the input end is connected to the output end of the current sampling circuit and the output end of the voltage sampling circuit, respectively. The calculation module calculates the output power of the photovoltaic module 12 based on the collected data of the output current and output voltage. The output end of the calculation module is connected to the control end of the inverter circuit 21 and the control end of the energy storage module 11, respectively. Based on the difference between the output power and the maximum power set by the inverter circuit 21, the calculation module outputs a control signal to the inverter circuit 21 and / or the energy storage module 11.

[0091] Through the above control signals, the switches in the inverter circuit 21 and / or the switches in the energy storage module 11 can be dynamically adjusted based on the output power of the photovoltaic panel 12. When the output power of the photovoltaic panel 12 exceeds the maximum power set by the inverter circuit 21, the MPPT module will control the switches in the inverter circuit 21 to operate at maximum power and control the operation of the switches in the energy storage module 11 based on the difference between the output power and the maximum power.

[0092] Furthermore, as shown in FIG6 , the specific method of controlling the inverter circuit 21 may be, but is not limited to, sending a control instruction to the inverter control module to trigger the inverter control module to control the switch transistors in the inverter circuit 21. Similarly, when the energy storage module 11 includes a battery 31 and a battery charge and discharge module 32, the specific method of controlling the energy storage module 11 may be, but is not limited to, sending a control instruction to the battery charge and discharge control module to trigger the battery charge and discharge module 32 to control the switch transistors in the battery charge and discharge module 32.

[0093] In summary, the MPPT module in this embodiment collects and calculates the output current and output voltage of the photovoltaic component 12, and controls the inverter circuit 21 and / or the energy storage module 11 according to the difference between the output power and the maximum power set by the inverter circuit 21 to achieve the maximum power point tracking function, thereby improving the energy conversion efficiency of the photovoltaic system.

[0094] Based on the above embodiment, the working process of the photovoltaic system is shown in FIG7 , and the working process includes the following steps:

[0095] (1) Sample the voltage Vpv and current Ipv of the photovoltaic module PV; (2) Calculate the PV power Ppv, perform MPPT disturbance calculation based on Ppv / Vpv / Ipv, and track the maximum power point of PV; (3) Control the switch tube of the inverter circuit according to the power; (4) Whether the power exceeds the maximum power Pinv_max of the inverter circuit; (5) If it exceeds, send a control instruction to the battery charge and discharge control module to start battery charging; if it does not exceed, keep the battery charging closed; (6) Control the duty cycle of the switch tube of the inverter circuit to work at the maximum power limit Pinv_max; (7) Calculate the battery charging power Pbat = Ppv-Pinv_max; (8) Control the switch tube of the battery charge and discharge circuit according to the battery charging power.

[0096] It should be noted that this application uses one photovoltaic module as an example, but it can be two or more photovoltaic modules. As shown in Figure 8, Figure 8 shows another example of this application, with two photovoltaic modules as input and two inverter circuits output in parallel. As shown in Figure 9, Figure 9 shows another example of this application, with two photovoltaic modules as input and two independent DC-DC modules, whose outputs are connected in parallel to the DC bus and then to the inverter circuit. Of course, this is not limited to the above examples.

[0097] It should also be noted that, in this specification, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0098] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A photovoltaic system, characterized in that: include: A photovoltaic module, used to provide power for the energy storage module and / or the inverter circuit; An energy storage module, the output end of which is connected to the output end of the photovoltaic module, and is used to receive the power output by the photovoltaic module, or to provide power for the inverter circuit when the photovoltaic module is not working; The inverter circuit has an input end connected to the output end of the photovoltaic component and the output end of the energy storage module, and is used to invert the power provided by the photovoltaic component and / or the energy storage module to the power grid.

2. The photovoltaic system according to claim 1, characterized in that: The photovoltaic component is provided with a backflow current threshold voltage, and the energy storage module is specifically used to receive the power output by the photovoltaic component, or when the photovoltaic component is not working, to provide the inverter circuit with a voltage less than the backflow current threshold voltage.

3. The photovoltaic system according to claim 1, characterized in that: Also includes: A protection switch, one end of which is connected to the output end of the photovoltaic component, and the other end of which is connected to the output end of the energy storage module and the input end of the inverter circuit, is used to disconnect when the photovoltaic component is not working and the energy storage module provides power for the inverter circuit.

4. The photovoltaic system according to claim 3, characterized in that: The protection switch is specifically used to receive a control instruction when the photovoltaic component is not working and the energy storage module provides power for the inverter circuit, and disconnect itself according to the control instruction.

5. The photovoltaic system according to claim 3, characterized in that: The protection switch is a relay, a MOS tube or a contactor.

6. The photovoltaic system according to claim 3, characterized in that: Also includes: A first auxiliary power supply, one end of which is connected to the output end of the photovoltaic assembly and the other end of which is connected to the power supply end of the protection switch, and is used to convert the output voltage of the photovoltaic assembly into a first preset voltage to power the protection switch; When the photovoltaic assembly is not working, the voltage output by the first auxiliary power supply is less than the first preset voltage, and the protection switch is disconnected.

7. The photovoltaic system according to claim 6, characterized in that: Also includes: A second auxiliary power supply, one end of which is connected to the output end of the photovoltaic module and the output end of the energy storage module The first end is connected to the power supply end of the inverter circuit, and the other end is connected to the power supply end of the inverter circuit, and is used to convert the output voltage of the photovoltaic component and / or the energy storage module into the second preset voltage to power each unit in the inverter circuit.

8. The photovoltaic system according to any one of claims 1 to 7, characterized in that: Also includes: The maximum power point tracking MPPT module has an input end connected to the output end of the photovoltaic component and a first output end connected to the control end of the inverter circuit, and is used to detect the output power of the photovoltaic component and perform maximum power point tracking according to the output power to control the action of the switch tube in the inverter circuit.

9. The photovoltaic system according to claim 8, characterized in that: The MPPT module also includes a second output terminal, and the second output terminal is connected to the control terminal of the energy storage module; The MPPT module is also used to determine whether the output power of the photovoltaic component exceeds the maximum power set by the inverter circuit. If it is greater, the switch tube in the inverter circuit is controlled to operate in the maximum power state, and the switch tube in the energy storage module is controlled according to the difference between the output power and the maximum power.

10. The photovoltaic system according to claim 9, characterized in that: The MPPT module comprises: A current sampling circuit, connected to the output end of the photovoltaic module, for collecting the output current of the photovoltaic module; A voltage sampling circuit is connected to the output end of the photovoltaic module and is used to collect the output voltage of the photovoltaic module; A calculation module, whose input end is respectively connected to the output end of the current sampling circuit and the output end of the voltage sampling circuit, and whose output end is respectively connected to the control end of the inverter circuit and the control end of the energy storage module, is used to calculate the output power according to the output current and the output voltage, and output a control signal to the inverter circuit and / or the energy storage module according to the output power and the maximum power set by the inverter circuit, so as to control the action of the switch tube in the inverter circuit and / or the switch tube in the energy storage module.

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