Inverter, and photovoltaic power generation system and method

Abstract

An inverter (1200), and a photovoltaic power generation system and method, which relate to the technical field of photovoltaic power generation. The photovoltaic power generation system comprises at least two photovoltaic panels (1100). The inverter (1200) comprises an alternating-current output module (120) and at least two direct-current / alternating-current conversion modules (110), wherein each direct-current / alternating-current conversion module (110) is detachably connected to the alternating-current output module (120); the direct-current / alternating-current conversion modules (110) are connected to the photovoltaic panels (1100), and are used for converting a direct current into a first alternating current, which direct current is outputted by the photovoltaic panels (1100); and the alternating-current output module (120) is used for processing the first alternating current to obtain a second alternating current, which has a stable waveform, and outputting the second alternating current to a load (1300) or a power grid (1400).

Description

Inverter, photovoltaic power generation system and method

[0001] Priority information

[0002] This application claims priority and benefits of patent application No. 202310952807.4 filed with the State Intellectual Property Office of China on July 28, 2023, and the entire text of which is incorporated herein by reference. Technical Field

[0003] The present application relates to the field of photovoltaic power generation, and in particular to an inverter, a photovoltaic power generation system and a method. Background Art

[0004] Photovoltaic (PV) power generation uses the photovoltaic effect at the interface of semiconductors to convert solar radiation directly into electrical energy. It primarily consists of three components: a solar panel, a controller, and an inverter. In practice, one solar panel is typically connected to one inverter. Therefore, if multiple solar panels are used, multiple inverters are required.

[0005] Summary of the Invention

[0006] This application proposes an inverter and a photovoltaic power generation system and method to improve the above-mentioned defects.

[0007] In a first aspect, an embodiment of the present application provides an inverter for use in a photovoltaic power generation system, wherein the photovoltaic power generation system includes at least two photovoltaic modules, and the inverter includes: an AC output module and at least two DC-AC conversion modules, each of the DC-AC conversion modules being detachably connected to the AC output module; the DC-AC conversion module is connected to the photovoltaic panel, and is used to convert the DC power output by the photovoltaic panel into a first AC power, and the AC output module is used to process the first AC power to obtain a second AC power with a stable waveform and output it to a load or a power grid.

[0008] Optionally, the DC-AC conversion module includes a photovoltaic input terminal, a first connecting terminal and a first weak-current terminal, and the AC output module includes an AC input and output terminal, at least two second connecting terminals and at least two second weak-current terminals; the DC-AC conversion module is connected to the photovoltaic panel through the photovoltaic input terminal; the AC output module is connected to the DC-AC conversion module through the second connecting terminal and the second weak-current terminal, wherein each second connecting terminal is connected to the corresponding first connecting terminal, and each second weak-current terminal is connected to the corresponding first weak-current terminal; the AC output module is connected to the power grid through the AC input and output terminals.

[0009] Optionally, the DC-AC conversion module includes a first sampling circuit and an interleaved flyback circuit; the interleaved flyback circuit is connected to the photovoltaic input terminal and the first connection terminal, and is used to convert the DC power output by the photovoltaic panel into a first AC power and output it to the AC output module through the first connection terminal and the second connection terminal in sequence; the first sampling circuit is connected to the photovoltaic input terminal and the first weak-current terminal, and is used to sample the voltage signal and current signal of the DC power output by the photovoltaic panel, and output the sampled voltage signal and current signal to the AC output module through the first weak-current terminal and the second weak-current terminal in sequence, and the AC output module implements maximum power point tracking based on the sampled voltage signal and current signal.

[0010] Optionally, the AC output module includes a processing circuit module and a CPU control module; the processing circuit module is connected to the second connection terminal and the AC input and output terminal, and is used to perform a commutation operation and an electrical characteristic stabilization operation on the first AC power and then output it to the power grid, wherein the commutation operation is used to convert the first AC power into a sine wave, and the electrical characteristic stabilization operation is used to convert the sine wave into a second AC power; the CPU control module is connected to the second weak current terminal and the processing circuit module, and is used to perform an insertion detection operation and realize maximum power point tracking, as well as control the DC-AC conversion module to perform a DC-AC conversion operation on the DC power output by the photovoltaic panel, and control the processing circuit module to perform a commutation operation on the first AC power.

[0011] Optionally, the AC output module also includes a communication module, which is connected to the CPU control module and is used to realize information interaction between the CPU control module and the server. When the AC output module is connected to a load or a power grid, the communication module obtains the operating power information of the load or the power grid so that the CPU control module can adjust the output power.

[0012] Optionally, the AC output module also includes a second sampling circuit, which connects each of the second weak-current terminals and the CPU control module, and is used to sample and scale the voltage signal and current signal output by the second weak-current terminal to the CPU control module; the CPU control module implements maximum power point tracking based on the voltage signal and current signal output by the second sampling circuit.

[0013] Optionally, the AC output module further includes a third sampling circuit, which connects the AC input / output terminal and the CPU control module and is used to sample the AC power input from the AC input / output terminal to the CPU control module; the CPU control module implements output control of the second AC power based on the sampled voltage value output by the third sampling circuit.

[0014] Optionally, the AC output module further includes a connection detection circuit, which is connected to each second weak-current terminal and the CPU control module, and is used to detect whether the second weak-current terminal is successfully connected to the first weak-current terminal on the DC-AC conversion module.

[0015] Optionally, the AC output module further includes a power supply module, which is connected to the second weak-current terminal and the CPU control module and is configured to supply power to the CPU control module based on a voltage output by the second weak-current terminal.

[0016] Optionally, the first connection terminal and the second connection terminal, as well as the first weak-current terminal and the second weak-current terminal are connected via a needle socket or a connecting wire.

[0017] In a second aspect, an embodiment of the present application also provides a photovoltaic power generation system, comprising at least two photovoltaic panels and the above-mentioned inverter, wherein the photovoltaic panels are used to convert solar energy into electrical energy and output direct current, and each of the photovoltaic panels is respectively connected to each of the direct-to-ac conversion modules of the inverter.

[0018] In a third aspect, an embodiment of the present application also provides a photovoltaic power generation method, which is applied to the above-mentioned inverter, and the method includes: the DC-AC conversion module converts the DC power output by the photovoltaic panel into a first AC power; the AC output module processes the first AC power to obtain a second AC power with a stable waveform and outputs it to the power grid or load.

[0019] Therefore, the present application provides an inverter, a photovoltaic power generation system, and a method. By splitting the inverter into two major parts: a DC-AC conversion module responsible for DC-AC conversion and an AC output module responsible for AC processing and output, and the DC-AC conversion module and the AC output module are detachably connected, one AC output module can be connected to multiple DC-AC conversion modules, thereby enabling one inverter to be connected to multiple photovoltaic panels. Therefore, by flexibly configuring multiple DC-AC conversion modules, one inverter can be connected to multiple photovoltaic panels for power generation, thereby reducing costs while improving ease of use.

[0020] Other features and advantages of the embodiments of the present application will be described in the following description and, in part, will become apparent from the description or be understood by practicing the embodiments of the present application. The objectives and other advantages of the embodiments of the present application can be achieved and obtained through the structures particularly pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0022] FIG1 shows a schematic diagram of an application environment applicable to an embodiment of the present application.

[0023] FIG2 shows a schematic structural diagram of an inverter proposed according to an embodiment of the present application.

[0024] FIG3 shows a schematic structural diagram of another inverter proposed according to an embodiment of the present application.

[0025] FIG4 shows a schematic structural diagram of a DC-AC conversion module proposed in an embodiment of the present application.

[0026] FIG5 shows a schematic structural diagram of an AC output module proposed in an embodiment of the present application.

[0027] FIG6 shows a schematic structural diagram of a photovoltaic power generation system proposed in an embodiment of the present application.

[0028] FIG7 shows a flow chart of a photovoltaic power generation method proposed in an embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application for protection, but merely represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work fall within the scope of protection of the present application.

[0030] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and should not be understood as indicating or implying relative importance.

[0031] The following is a brief description of some of the nouns involved in the specific implementation:

[0032] Pulse width modulation (PWM): An analog control method that modulates the bias of the transistor base or MOS tube gate according to the corresponding load changes to achieve a change in the transistor or MOS tube conduction time, thereby changing the output of the switching regulated power supply. This method can keep the output voltage of the power supply constant when the operating conditions change.

[0033] Maximum power point tracking (MPPT): When a power generation system's connected load is aligned with the load curve that maximizes power transmission efficiency, the system achieves optimal power generation efficiency. The load characteristic with the highest power transmission efficiency is called the maximum power point (MPP). MPPT seeks to find this maximum power point and maintain the load characteristics at this point.

[0034] Please refer to Figure 1, which shows a schematic diagram of an application environment suitable for an embodiment of the present application. The inverter provided in the embodiment of the present application can be applied to a home energy storage system 100 as shown in Figure 1. The energy exchange system 100 includes a photovoltaic panel 1100, an inverter 1200, a load 1300 and a power grid 1400. The photovoltaic panel 1100 is connected to the load 1300 and the power grid 1400 through the inverter 1200. The load 1300 can be a household appliance such as a computer, etc., which is not specifically limited here. The photovoltaic panel 1100 converts solar radiation energy into direct current and transmits it to the inverter 1200. The inverter 1200 converts direct current into alternating current and transmits the electrical energy to the load 1300 or the power grid 1400.

[0035] As an embodiment, the inverter 1200 may also be connected to an energy storage battery 1500, and the energy storage battery 1500 may be connected to the load 1300 and the grid 1400. Specifically, the inverter 1200 may transmit electrical energy to the energy storage battery 1500 for storage. The energy storage battery may provide electrical energy when the load requires it, and may supplement power when the grid power is insufficient.

[0036] The above application environment is only an example for ease of understanding. It should be understood that the embodiments of the present application are not limited to the above application environment.

[0037] The inverter, photovoltaic power generation system and method provided in the embodiments of the present application will be described in detail below through specific embodiments.

[0038] Please refer to Figure 2, which shows a structural schematic diagram of an inverter provided in an embodiment of the present application. The inverter is applied to a photovoltaic power generation system and includes: at least two DC-AC conversion modules 110 and an AC output module 120, and each DC-AC conversion module 110 can be detachably connected to the AC output module 120.

[0039] Specifically, the DC-AC conversion module 110 is connected to the photovoltaic panel. Under the irradiation of sunlight, the photovoltaic panel converts solar energy into electrical energy to generate DC power, and inputs it into the connected DC-AC conversion module 110. The DC-AC conversion module 110 is used to convert the DC power into a first AC power and then input it into the connected AC output module 120. The AC output module 120 is used to process the first AC power to obtain a second AC power with a stable waveform. Furthermore, the AC output module 120 can be connected to the power grid, so as to connect the second AC power to the load or the power grid.

[0040] As an implementation method, the AC output module 120 can be connected to 8 DC-AC conversion modules 110, that is, the inverter can be connected to 8 photovoltaic panels at the same time, and after DC-AC conversion and subsequent processing of the DC power output by all photovoltaic panels, obtain stable AC power and output it to the power grid.

[0041] Therefore, the inverter provided in the present application is divided into two major parts: a DC-AC conversion module responsible for DC-AC conversion and an AC output module responsible for AC processing and output. The DC-AC conversion module and the AC output module are detachably connected, so that one AC output module can be connected to multiple DC-AC conversion modules, thereby ensuring that one inverter can be connected to multiple photovoltaic panels. Therefore, by flexibly configuring multiple DC-AC conversion modules, one inverter can be connected to multiple photovoltaic panels for power generation, thereby reducing costs while improving ease of use.

[0042] Specifically, please refer to Figure 3, which shows a structural schematic diagram of another inverter provided in an embodiment of the present application. The inverter is applied to a photovoltaic power generation system, including: at least two DC-AC conversion modules 120 and an AC output module 220. Each DC-AC conversion module 120 can be detachably connected to the AC output module 220. Each DC-AC conversion module 120 is connected to the AC output module 220 through a terminal. As an embodiment, the terminals can be connected by means of pin sockets or connecting wires to achieve detachable connection.

[0043] Specifically, the DC-AC conversion module 210 includes a photovoltaic input terminal, a first connection terminal, and a first weak-current terminal. The AC output module 220 includes AC input and output terminals, at least two second connection terminals, and at least two second weak-current terminals. In one embodiment, the second connection terminals and the second weak-current terminals are arranged alternately on the AC output module. Therefore, every two second connection terminals and the second weak-current terminals can be considered a set of connection terminals. The AC output module 220 is connected to a single DC-AC conversion module 210 via this set of connection terminals.

[0044] Furthermore, when connecting the DC-AC conversion module 210 to the AC output module 220, the first connection terminal of each DC-AC conversion module 210 can be connected to the corresponding second connection terminal on the AC output module 220, and the first weak-current terminal of each DC-AC conversion module 210 can be connected to the corresponding second weak-current terminal on the AC output module 220. At the same time, the DC-AC conversion module 210 is connected to the photovoltaic panel through the photovoltaic input terminal, and the AC output module 220 is connected to the load or the power grid through the AC input and output terminals.

[0045] Furthermore, the photovoltaic input terminal can have two pins, namely PV+ pin and PV- pin, corresponding to the positive and negative poles of the direct current input by the photovoltaic panel, and the first connection terminal and the second connection terminal also each have two pins, namely L1 and L2, corresponding to the positive and negative poles of the first alternating current. Among them, the DC-AC conversion module 210 receives the DC power transmitted by the photovoltaic panel through the photovoltaic input terminal, and obtains the first AC power after DC-AC conversion, and then outputs the first AC power to the AC output module 220 through the first connection terminal and the second connection terminal, so that the AC output module 220 can obtain the second AC power based on the first AC power, and thus transmit the second AC power to the power grid through the AC input and output terminals; the first weak current terminal and the second weak current terminal each have at least six pins, two pins are connected to the current output signal line, two pins are connected to the voltage output signal line, and two pins are connected to the drive signal line. Therefore, the DC-AC conversion module 210 can output the DC voltage signal and current signal to the AC output module 220 through the first weak current terminal and the second weak current terminal. The AC output module 220 realizes maximum power regulation based on the voltage signal and the current signal, and can send a drive signal to the DC-AC conversion module 210 through the first weak current terminal and the second weak current terminal to drive the DC-AC conversion module to perform the DC-AC conversion operation.

[0046] As an embodiment, the first weak current terminal is further provided with a ground pin and a connection mark pin, wherein the connection mark pin is grounded through a resistor and is used to detect whether the DC-AC conversion module is inserted into the AC output module.

[0047] As an implementation manner, the number of the second connection terminals and the second weak-current terminals is eight, that is, the AC output module 220 can be connected to eight DC-AC conversion modules 210 .

[0048] As an embodiment, the AC input and output terminals of the AC output module 220 are connected to AC power from the grid. Normal operation output is performed only when and only when the AC output module 220 detects that an AC voltage is connected to the AC input and output terminals. If no AC voltage is detected on the AC input and output terminals, or the AC voltage is abnormal, the AC output to the grid is stopped.

[0049] Therefore, the inverter provided in the present application is divided into two major parts: a DC-AC conversion module responsible for DC-AC conversion and an AC output module responsible for AC processing and output. The DC-AC conversion module and the AC output module are detachably connected through the corresponding first connection terminal and the second connection terminal and the first weak-current terminal and the second weak-current terminal. The DC-AC conversion module is connected to the photovoltaic panel through the photovoltaic input terminal, and the AC output module is connected to the power grid through the AC input and output module. Therefore, by flexibly configuring multiple DC-AC conversion modules, one inverter can be connected to multiple photovoltaic panels for power generation, which reduces costs while improving ease of use.

[0050] Please refer to Figure 4, which shows a structural schematic diagram of a DC-AC conversion module provided in an embodiment of the present application. The DC-AC conversion module includes a photovoltaic input terminal, a first connecting terminal, a first weak-current terminal, a first sampling circuit 301 and an interleaved flyback circuit 302, wherein the interleaved flyback circuit 302 is connected to the photovoltaic input terminal and the first connecting terminal, the first sampling circuit 301 is connected to the photovoltaic input terminal and the first weak-current terminal, the interleaved flyback circuit 302 is used to convert the DC power output by the photovoltaic panel through the photovoltaic input terminal into a first AC power, and then output it through the first connecting terminal, the first sampling circuit is used to sample the voltage value and current value of the DC power output by the photovoltaic panel, and output the sampled voltage value and current value to the DC-AC conversion module through the first weak-current terminal.

[0051] As an embodiment, an interleaved flyback circuit includes at least two flyback circuits, each of which is interleaved and connected in parallel. Each flyback circuit consists of a switching MOSFET and its drive circuit, a flyback transformer, and a diode. The diode is connected in series with the flyback transformer's secondary coil for output rectification. The switching MOSFET and its drive circuit are connected to both ends of the flyback transformer's primary coil to control the on / off of the excitation voltage on the flyback transformer's primary coil. When the switching MOSFET is in the on state, the flyback transformer is in the primary-side freewheeling phase, and the excitation voltage charges the flyback transformer's primary coil. When the switching MOSFET is in the off state, the energy stored in the flyback transformer's primary coil is transferred to the secondary coil. Therefore, the switching MOSFETs of the two interleaved flyback circuits are controlled by two drive signals with a phase difference of 180 degrees, and the interleaved conduction is controlled, thereby modulating the direct current input from the photovoltaic panel into a first alternating current. In particular, the first alternating current can be a half-sine wave. Furthermore, the primary coil of the flyback transformer in each flyback circuit is connected to the photovoltaic input terminal, and the direct current output from the photovoltaic input terminal serves as the excitation voltage of the primary coil of the flyback transformer. The secondary coil of the flyback transformer in each flyback circuit is connected to the first connection terminal, so as to output the formed first alternating current to the direct-to-alternating current conversion module via the first connection terminal.

[0052] As an embodiment, the interleaved flyback circuit 302 may further include a leakage inductance absorption circuit connected across the primary coil of the flyback transformer to absorb leakage inductance generated on the primary coil of the flyback transformer when the switching MOSFET is turned off. Specifically, the leakage inductance absorption circuit may be any one of a storage capacitor, a passive clamp absorption circuit such as an RCD absorption circuit, and an active clamp absorption circuit. Passive clamp absorption circuits and active clamp absorption circuits can also reduce the impact of voltage spikes generated when the MOSFET is turned off on the interleaved flyback circuit.

[0053] In one embodiment, the first sampling circuit may be composed of an analog switch, a holding capacitor, and a non-inverting circuit with a unity gain of 1. The first sampling circuit operates in one of two states: a sampling state and a holding state. In the sampling state, the switch is turned on and tracks the level changes of the analog input signal until the holding signal is received. In the holding state, the switch is turned off, the tracking process stops, and the instantaneous value of the input signal before the switch is turned off is maintained, thereby achieving signal sampling and obtaining the voltage and current values ​​of the DC power input to the photovoltaic panel.

[0054] Therefore, the present application provides an inverter, including multiple DC-AC conversion modules responsible for DC-AC conversion and an AC output module responsible for AC processing and output. The AC output module can be connected to multiple DC-AC conversion modules. The DC-AC conversion module includes a first sampling circuit and an interleaved flyback circuit. The DC-AC conversion is performed through the interleaved flyback circuit to convert the DC power output by the photovoltaic panel into a first AC power. The voltage and current values ​​of the DC power are sampled by the first sampling circuit and output to the AC output module. The AC output module is used to convert the first AC power into a second AC power with better stability and output it to the power grid. Therefore, by flexibly configuring multiple DC-AC conversion modules, one inverter can be connected to multiple photovoltaic panels for power generation, thereby reducing costs while improving ease of use.

[0055] Please refer to Figure 5, which shows a structural schematic diagram of an AC output module provided in an embodiment of the present application. The AC output module includes at least: AC input and output terminals, at least two second connection terminals, at least two second weak-current terminals, a processing circuit module 401 and a CPU control module 402, wherein the second connection terminal corresponds to the first connection terminal on the DC-AC conversion module, and the second weak-current terminal corresponds to the first weak-current terminal on the DC-AC conversion module, thereby realizing the connection between the AC output module and multiple DC-AC conversion modules. Specifically, the processing circuit module 401 is connected to the AC input and output terminals and each second connection terminal, and is used to receive the first AC power output by all the DC-AC conversion modules connected to the AC output module through the second connection terminals, and after performing commutation operation and electrical characteristic stabilization operation processing on the first AC power, output it to the power grid through the AC input and output terminals; the CPU control module 402 is connected to the processing circuit module 401 and each second weak-current terminal, and is used to achieve maximum power point tracking based on the DC power sampled voltage and current values ​​output by all the DC-AC conversion modules connected to the AC output module through the second weak-current terminals, and output a drive signal to the DC-AC conversion module through the second weak-current terminal to control the DC-AC conversion module to perform the DC-AC conversion operation to obtain the first AC power, and control the processing circuit module to perform commutation operation and electrical stability operation on the first AC power, wherein the commutation operation is used to convert the first AC power into a sine wave, and the electrical stability operation is used to improve the power quality of the sine wave.

[0056] As an embodiment, the AC output module also includes a communication module 403. The communication module 403 is connected to and interacts with the CPU control module 402, enabling the CPU control module 402 to transmit operating information of the DC-AC conversion module and the AC output module to the smart terminal via the communication module 403. The CPU control module 402 can also receive and execute commands from the smart terminal via the communication module 403. When the AC output module is connected to a load or a power grid, the communication module 403 can obtain operating power information of the load or power grid to enable the CPU control module to adjust the output power. Furthermore, the operating information may include sampled voltage and current values ​​of the DC power on the DC-AC conversion module, sampled voltage values ​​of the second AC power on the AC output module, and other information. The smart terminal may be a device capable of information exchange, such as a smartphone or a computer.

[0057] Specifically, the CPU control module 402 calculates and tracks the maximum power point based on the DC sampling voltage and current values ​​output by the second weak-current terminal through the MPPT algorithm, so that the inverter can extract the maximum power from the photovoltaic panel. Exemplarily, the MPPT algorithm may include the Constant Voltage Tracking (CVT) method, the Perturbation And Observation method (P&O) method, the Incremental Conductance method (INC) method, the conductance increment method based on the gradient variable step size, and the like.

[0058] Specifically, the CPU control module 402 controls the DC-AC conversion operation of the DC-AC output module and the commutation operation of the processing circuit module 401 through pulse width modulation technology. Furthermore, the CPU control module 402 sends a PWM signal to the processing circuit module 401 to drive the MOSFET for commutation in the processing circuit module. The CPU control module 402 sends a PWM signal to each second weak-current terminal, and the second weak-current terminal transmits the PWM signal to the connected DC-AC conversion module via the connected first weak-current terminal, so as to drive the MOSFET used by the DC-AC conversion module to generate the first AC power through interleaved flyback.

[0059] As an embodiment, the processing circuit module 401 may include a commutation circuit and at least one of an electromagnetic compatibility (EMC) circuit, a filtering circuit and a lightning protection circuit, wherein the commutation circuit is used to perform a commutation operation to convert the first AC power into a sine wave with a stable frequency. Exemplarily, the commutation circuit can be a full-bridge inverter circuit, and the specific frequency of the sine wave can be determined by the frequency of the power grid to which the inverter is connected, for example, it can be a civil AC sine wave with a sine of 50Hz or a civil AC sine wave with a sine of 60Hz; an electromagnetic compatibility (EMC) circuit, a filtering circuit and a lightning protection circuit, the EMC circuit is used to reduce electromagnetic radiation and interference to ensure the reliability and safety of the AC output module, the filtering circuit is used to suppress the harmonic content of the sine wave and improve the power quality, exemplarily, the filtering circuit can be any one of an L-type filtering circuit, an LC filtering circuit or an LCL filtering circuit, and the lightning protection circuit is used to prevent lightning strikes to ensure the stable operation of the AC output module. Therefore, after the first alternating current is input into the processing circuit module 401 through the second connection terminal, it is converted into a frequency-stable sine wave through the commutation circuit, and then the stability is improved in sequence through the electromagnetic compatibility circuit, the filtering circuit and the lightning protection circuit to obtain the second alternating current and output it, thereby improving the power supply quality of the AC output module.

[0060] As an implementation method, the CPU control module 402 may use a DSP28035 chip as a control core.

[0061] As an embodiment, the AC output module further includes a second sampling circuit 404, which is connected to the CPU control module 402 and each second weak-current terminal, and is used to sample and scale the voltage and current values ​​output by the second weak-current terminal to the CPU control module 402. Specifically, each direct-to-AC conversion module connected to the AC output module outputs the DC sampling voltage and current values ​​obtained by the first sampling circuit to the AC output module through the first weak-current terminal, and the first weak-current terminal is connected to the second weak-current terminal, and the second sampling circuit scales down the DC sampling voltage value connected to the second weak-current terminal and amplifies the DC sampling current value connected to the second weak-current terminal, and then outputs the sampled voltage and sampled current values ​​to the CPU control module 402 via an operational amplifier, so that the CPU control module 402 implements maximum power point tracking based on the sampled voltage and sampled current values.

[0062] As an embodiment, the AC output module further includes a third sampling circuit 405, which is connected to the AC input / output terminal and the CPU control module 402. Furthermore, the third sampling circuit 405 is used to sample the AC power inputted by the AC input / output terminal and output it to the CPU control module 402. Furthermore, the CPU control module 402 controls the output of the second AC power based on the sampled AC voltage value inputted by the AC input / output terminal. Specifically, only when the CPU control module 402 detects that the AC voltage inputted by the AC input / output terminal is a standard AC voltage, does it control the AC output module to output the second AC power to the load or the grid, where the standard AC voltage is the mains voltage. Furthermore, the CPU control module 402 can also detect whether the voltage and current values ​​inputted by the second weak-current terminal are within a positive charge range. Only when the voltage and current values ​​inputted by the second weak-current terminal are within the positive charge range does it output the second AC power to the load or the grid, thereby ensuring the stability of the normal operation of the inverter.

[0063] As an embodiment, the AC output module also includes a connection detection circuit 406, which is connected to the CPU control module 402 and each second weak-current terminal, and is used to detect whether the AC output module is successfully connected to the DC-AC conversion module. Furthermore, it is achieved by detecting whether the second weak-current terminal on the AC output module is successfully connected to the first weak-current terminal on the DC-AC conversion module. Specifically, a ground pin and a connection mark pin are also provided on the first weak-current terminal, wherein the connection mark pin is grounded through a resistor, and the CPU control module 402 detects the output level of each second weak-current terminal connected to the connection detection circuit 406 in a polling manner. When the first weak-current terminal and the second weak-current terminal are not connected, the default detection level is a high level. When the first weak-current terminal is connected to the second weak-current terminal, that is, the DC-AC conversion module is connected to the AC output module, since the pin on the first weak-current terminal of the DC-AC conversion module is grounded, the level detected by the CPU control module 402 will become a low level. Therefore, when the CPU control module 402 detects that the output level on a second weak-current terminal connected to the connection detection circuit 406 is a low level, it can be confirmed that the AC output module is successfully connected to the corresponding DC-AC conversion module on the second weak-current terminal, and then the DC-AC conversion module is sampled and waved, etc., to improve the efficiency of the AC output module.

[0064] As an implementation manner, the CPU control module 402 may also receive an insertion confirmation signal sent by the intelligent terminal through the communication module 403 to detect whether the DC-AC conversion module is successfully connected to the AC output module.

[0065] As an embodiment, the AC output module further includes a power supply module 407, which is connected to the CPU control module 402 and each second weak current terminal for supplying power to the CPU control module 402. Exemplarily, the power supply module 407 can be a dc-dc conversion circuit, and the direct current provided by the photovoltaic panels output by each second weak current terminal is first connected in parallel through diodes, and then generated by the dc-dc conversion circuit in a flyback manner. Furthermore, the power supply module 407 can also be connected to the communication module 403, the second sampling circuit 404, and the third sampling circuit 405, and provide power thereto.

[0066] As an embodiment, the AC output module also includes a drive output module 408, which connects the CPU control module 402 with each second weak-current terminal and the part of the processing circuit module 401 responsible for performing the commutation operation. The drive output module 408 converts the level of the PWM output by the CPU control module 402 and outputs at least three groups of PWM signals, one group of which is sent to the processing circuit module 401 to drive the MOSFET for commutation in the processing circuit module, and the remaining PWM signals are sent to the second weak-current terminal to confirm that it is successfully connected to the first weak-current terminal, and are used to be transmitted to the connected DC-AC conversion module via the connected first weak-current terminal, driving the DC-AC conversion module for interleaved flyback to generate the MOSFET for the first AC power.

[0067] Therefore, an inverter provided in an embodiment of the present application includes multiple DC-AC conversion modules responsible for DC-AC conversion and an AC output module responsible for AC processing and output. The AC output module can be connected to multiple DC-AC conversion modules. The DC-AC conversion module is used to connect to the photovoltaic panel and convert the DC power output by the photovoltaic panel into a first AC power. The AC output module includes at least: a processing circuit module, a CPU control module and a communication module. The first AC power is converted into a second AC power with better stability through the processing circuit module and output to the power grid. The CPU control module and the communication module are used to control the DC-AC conversion module and the processing circuit module to improve the quality of the power supply. Therefore, by flexibly configuring multiple DC-AC conversion modules, one inverter can be connected to multiple photovoltaic panels for power generation, thereby reducing costs while improving ease of use.

[0068] Please refer to Figure 6, which shows a schematic diagram of the structure of a photovoltaic power generation system provided in an embodiment of the present application. The system includes at least two photovoltaic panels and an inverter as described in any of the above embodiments. The photovoltaic panels are used to convert solar energy into electrical energy and output direct current. Each photovoltaic panel is connected to each of the DC-AC conversion modules of the inverter. Specifically, the photovoltaic panels are connected to the DC-AC conversion modules via photovoltaic input terminals. Therefore, the photovoltaic power generation system can flexibly configure multiple DC-AC conversion modules, allowing a single inverter to connect to multiple photovoltaic panels for power generation, reducing costs while improving ease of use.

[0069] Please refer to FIG7 , which shows a flow chart of a photovoltaic power generation method provided in an embodiment of the present application, which is applied to the inverter described in any of the above embodiments. The method includes:

[0070] S1: The DC-AC conversion module converts the DC power output by the photovoltaic panel into a first AC power.

[0071] As an embodiment, the DC-AC conversion module includes a first sampling circuit and an interleaved flyback circuit. The DC-AC conversion module converts the DC power output by the photovoltaic panel into the first AC power by performing DC-AC conversion through the interleaved flyback circuit, converting the DC power output by the photovoltaic panel into the first AC power, sampling the voltage value and current value of the DC power through the first sampling circuit and outputting them to the AC output module.

[0072] S2: The AC output module processes the first AC power to obtain a second AC power with a stable waveform and outputs the second AC power to a power grid or a load.

[0073] As an embodiment, the AC output module can be connected to multiple DC-AC conversion modules, and the AC output module includes at least: a processing circuit module, a CPU control module and a communication module. The method by which the AC output module processes the first AC power to obtain a second AC power with a stable waveform and outputs it to the power grid or load can be: converting the first AC power into a second AC power with better stability through the processing circuit module and outputting it to the power grid or load, and controlling the DC-AC conversion module and the processing circuit module through the CPU control module and the communication module to improve the quality of the power supply.

[0074] As an implementation method, S2 may further include:

[0075] S21: The AC output module obtains a connection detection result, where the connection detection result is used to indicate whether the DC-AC conversion module is successfully connected to the AC output module.

[0076] Specifically, the AC output module obtains the detection result by detecting the electrical level on each of its second weak-current terminals. If the detection level is high, the detection result is that the second weak-current terminal is not connected to the DC-AC conversion module; if the detection level is low, the detection result is that the second weak-current terminal is successfully connected to the DC-AC conversion module.

[0077] As an embodiment, the AC output module also includes a connection detection circuit module, the CPU control module is connected to the connection detection circuit module, and the connection detection circuit module is connected to each second low-voltage terminal. Therefore, the CPU control module obtains the detection level through the connection detection circuit and obtains the detection result based on the detection level.

[0078] S22: If the connection detection result shows that the DC-AC conversion module is successfully connected to the AC output module, the AC output module processes the first AC power to obtain a second AC power with a stable waveform and transmits the second AC power to the power grid or the load.

[0079] The specific implementation of method S22 may refer to the relevant embodiments of the inverter described above, and will not be described in detail here.

[0080] Therefore, the photovoltaic power generation method provided in the present application is applied to an inverter, and the inverter includes a DC-AC conversion module and an AC output module. The DC-AC conversion module converts the DC power output by the photovoltaic panel into a first AC power. The AC output module processes the first AC power to obtain a second AC power with a stable waveform and outputs it to the power grid. By flexibly configuring the connection between multiple DC-AC conversion modules and an AC output module, one inverter can be connected to multiple photovoltaic panels for power generation, thereby reducing costs and improving ease of use.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An inverter, characterized in that: Applied to a photovoltaic power generation system, the photovoltaic power generation system includes at least two photovoltaic panels, and the inverter includes: An AC output module and at least two DC-AC conversion modules, each of the DC-AC conversion modules being detachably connected to the AC output module; The DC-AC conversion module is connected to the photovoltaic panel and is used to convert the DC power output by the photovoltaic panel into a first AC power. The AC output module is used to process the first AC power to obtain a second AC power with a stable waveform and output it to a load or a power grid.

2. The inverter according to claim 1, characterized in that: The DC-AC conversion module includes a photovoltaic input terminal, a first connection terminal and a first weak current terminal, and the AC output module includes an AC input and output terminal, at least two second connection terminals and at least two second weak current terminals; The DC-AC conversion module is connected to the photovoltaic panel via the photovoltaic input terminal; The AC output module is connected to the DC-AC conversion module through the second connecting terminal and the second weak-current terminal, wherein each of the second connecting terminals is connected to the corresponding first connecting terminal, and each of the second weak-current terminals is connected to the corresponding first weak-current terminal; The AC output module is connected to the load or the power grid through the AC input and output terminals.

3. The inverter according to claim 2, characterized in that: The DC-AC conversion module includes a first sampling circuit and an interleaved flyback circuit; The interleaved flyback circuit is connected to the photovoltaic input terminal and the first connection terminal, and is used to convert the direct current output by the photovoltaic panel into a first alternating current and output it to the alternating current output module through the first connection terminal and the second connection terminal in sequence; The first sampling circuit is connected to the photovoltaic input terminal and the first weak-current terminal, and is used for sampling the voltage signal and current signal of the direct current output by the photovoltaic panel, and outputting the sampled voltage signal and current signal to the AC output module through the first weak-current terminal and the second weak-current terminal in sequence, and the AC output module realizes maximum power point tracking based on the sampled voltage signal and current signal.

4. The inverter according to claim 2, characterized in that: The AC output module includes a processing circuit module and a CPU control module; The processing circuit module is connected to the second connection terminal and the AC input and output terminal, and is used to perform commutation operation and electrical characteristic stabilization operation on the first AC power and then output it to the power grid, wherein the commutation operation is used to convert the first AC power into a sine wave, and the electrical characteristic stabilization operation is used to convert the sine wave into a second AC power; The CPU control module is connected to the second weak-current terminal and the processing circuit module, and is used to perform an insertion detection operation and realize maximum power point tracking, and to control the DC-AC conversion module to perform a DC-AC conversion operation on the DC power output by the photovoltaic panel, and to control the processing circuit module to perform a commutation operation on the first AC power.

5. The inverter according to claim 4, characterized in that: The AC output module also includes a communication module, which is connected to the CPU control module and is used to realize information interaction between the CPU control module and the intelligent terminal. When the AC output module is connected to a load or a power grid, the communication module obtains the operating power information of the load or the power grid so that the CPU control module can adjust the output power.

6. The inverter according to claim 4, characterized in that: The AC output module further includes a second sampling circuit, which is connected to each of the second weak-current terminals and the CPU control module and is used for sampling and scaling the voltage signal and current signal output by the second weak-current terminal to the CPU control module; The CPU control module implements maximum power point tracking based on the voltage signal and the current signal output by the second sampling circuit.

7. The inverter according to claim 4, characterized in that: The AC output module further includes a third sampling circuit, which is connected to the AC input / output terminal and the CPU control module and is used to sample the AC power input from the AC input / output terminal to the CPU control module; The CPU control module implements output control of the second alternating current based on the sampled voltage value output by the third sampling circuit.

8. The inverter according to claim 4, characterized in that: The AC output module also includes a connection detection circuit, which is connected to each second weak-current terminal and the CPU control module and is used to detect whether the second weak-current terminal is successfully connected to the first weak-current terminal on the DC-AC conversion module.

9. The inverter according to claim 4, characterized in that: The AC output module further includes a power supply module, which is connected to the second weak-current terminal and the CPU control module and is used to supply power to the CPU control module based on the voltage output by the second weak-current terminal.

10. A photovoltaic power generation system, comprising at least two photovoltaic panels and the inverter according to any one of claims 1 to 9, wherein the photovoltaic panels are used to convert solar energy into electrical energy and output direct current, and each of the photovoltaic panels is respectively connected to each of the direct-to-alternating current conversion modules of the inverter.

11. A photovoltaic power generation method, characterized in that: Applied to the inverter according to any one of claims 1 to 9, the method comprises: The DC-AC conversion module converts the DC power output by the photovoltaic panel into a first AC power; The AC output module processes the first AC power to obtain a second AC power with a stable waveform and outputs the second AC power to a power grid or a load.

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