Inverter apparatus and control method therefor, and photovoltaic system

Abstract

Provided in the embodiments of the present disclosure are an inverter apparatus and a control method therefor, and a photovoltaic system. The inverter apparatus comprises: a housing; a first input port, which is suitable for being coupled to a first photovoltaic cell; a second input port, which is suitable for being coupled to a second photovoltaic cell that is different from the first photovoltaic cell; an output port, which is suitable for being coupled to an alternating-current power grid or device; a direct current-direct current conversion circuit, which is located in the housing, wherein the direct current-direct current conversion circuit is coupled to the first input port on an input side thereof, and is coupled to the second input port on an output side thereof; a direct current-alternating current conversion circuit, which is located in the housing, wherein the direct current-alternating current conversion circuit is coupled to the second input port on an input side thereof, and is coupled to the output port on an output side thereof; and a controller, which is coupled to the direct current-direct current conversion circuit and the direct current-alternating current conversion circuit, and controls the direct current-direct current conversion circuit and the direct current-alternating current conversion circuit. By means of the embodiments of the present disclosure, two photovoltaic cells with different voltage levels can be efficiently connected to an alternating-current power grid or device.

Description

Inverter device, control method thereof, and photovoltaic system Technical Field

[0001] The present disclosure relates to photovoltaic power generation and power electronics technology, and more particularly, to an inverter device, a photovoltaic system including the inverter device, a method and a control device for controlling the inverter device, a computer-readable storage medium, and a computer program product. Background Art

[0002] Photovoltaic power generation utilizes the photovoltaic effect of photovoltaic cells to convert solar energy or light energy into electrical energy. It offers numerous advantages, including being clean, environmentally friendly, and renewable. To ensure that the electricity generated by photovoltaic cells meets the requirements of the grid or load, and to improve the power generation efficiency of photovoltaic cells, power conversion equipment, such as inverters, is typically required to convert the voltage or current generated by the photovoltaic cells into the required voltage and current.

[0003] In photovoltaic power generation technology, inverters can convert the output of a large number of photovoltaic modules into power for supply to the grid or load, or they can convert the output of a single or small number of photovoltaic modules into power for supply to the grid or load. The latter are also called microinverters or module-level inverters. Currently, with the continuous development of photovoltaic technology, new types of photovoltaic modules are constantly emerging. However, there is a lack of inverter equipment, especially microinverters, to connect these photovoltaic modules to the grid or load. Summary of the Invention

[0004] To at least partially address the above and other possible problems, embodiments of the present disclosure provide an inverter device, a photovoltaic system, a method and control device for controlling the inverter device, a computer-readable storage medium, and a computer program product.

[0005] According to a first aspect of the present disclosure, an inverter device is provided, which includes: a housing; a first input port, suitable for coupling to a first photovoltaic cell; a second input port, suitable for coupling to a second photovoltaic cell different from the first photovoltaic cell; an output port, suitable for coupling to an AC power grid or device; a DC-DC conversion circuit, located in the housing, the DC-DC conversion circuit coupled to the first input port on its input side and to the second input port on its output side; a DC-AC conversion circuit, located in the housing, the DC-AC conversion circuit coupled to the second input port on its input side and to the output port on its output side; and a controller, coupled to the DC-DC conversion circuit and the DC-AC conversion circuit, and configured to control the DC-DC conversion circuit and the DC-AC conversion circuit.

[0006] In some embodiments of the present disclosure, the controller is configured to control the DC-AC conversion circuit to track the maximum power point of the second photovoltaic cell, and control the DC-DC conversion circuit to use the optimal operating voltage associated with the maximum power point of the second photovoltaic cell as the desired output voltage and track the maximum power point of the first photovoltaic cell.

[0007] In some embodiments of the present disclosure, the DC-AC conversion circuit includes a DC-DC converter and a DC-AC converter coupled in series, and wherein the controller is configured to control the DC-DC converter in the DC-AC conversion circuit to track the maximum power point of the second photovoltaic cell, and to control the DC-DC conversion circuit to use an optimal operating voltage associated with the maximum power point of the second photovoltaic cell as a desired output voltage and track the maximum power point of the first photovoltaic cell.

[0008] In some embodiments of the present disclosure, the first input port includes multiple sub-input ports, and the DC-DC conversion circuit includes multiple DC-DC converters, which are respectively coupled to the multiple sub-input ports on their input sides and are connected in series, in parallel, or in series and in parallel on their output sides.

[0009] In some embodiments of the present disclosure, the first photovoltaic cell includes multiple groups of photovoltaic cells, the multiple sub-input ports are suitable for being respectively coupled to the multiple groups of photovoltaic cells, and the controller is configured to control the DC-AC conversion circuit to track the maximum power point of the second photovoltaic cell, and control the corresponding DC-DC converters of the multiple DC-DC converters to track the maximum power point of a group of photovoltaic cells corresponding to the corresponding DC-DC converter.

[0010] In some embodiments of the present disclosure, the DC-AC conversion circuit includes an LLC-based inverter.

[0011] In some embodiments of the present disclosure, the DC-DC converter in the DC-AC conversion circuit includes a flyback DC boost converter, and the DC-AC converter in the DC-AC conversion circuit includes a full-bridge inverter.

[0012] In some embodiments of the present disclosure, the first photovoltaic cell comprises a crystalline silicon cell, the second photovoltaic cell comprises a perovskite cell, and the DC-DC conversion circuit comprises a DC boost converter.

[0013] In some embodiments of the present disclosure, the first photovoltaic cell comprises a perovskite cell, the second photovoltaic cell comprises a crystalline silicon cell, and the DC-DC conversion circuit comprises a DC buck converter.

[0014] According to a second aspect of the present disclosure, a photovoltaic system is provided, comprising: a photovoltaic assembly including: a first photovoltaic cell; a second photovoltaic cell assembled with the first photovoltaic cell; and an inverter according to the first aspect, coupled to the photovoltaic assembly.

[0015] In some embodiments of the present disclosure, the first photovoltaic cell includes a crystalline silicon cell located at the bottom of the photovoltaic module, and the second photovoltaic cell includes a perovskite cell located at the top of the photovoltaic module, or the first photovoltaic cell includes a perovskite cell located at the top of the photovoltaic module, and the second photovoltaic cell includes a crystalline silicon cell located at the bottom of the photovoltaic module.

[0016] In some embodiments of the present disclosure, the first photovoltaic cell and the second photovoltaic cell are assembled together in a stacked manner.

[0017] According to a third aspect of the present disclosure, a method for controlling an inverter device is provided, the method comprising: obtaining first sensing information indicating an output voltage and current of a first photovoltaic cell, the first photovoltaic cell being coupled to an AC power grid or device via a first input port, a DC-DC conversion circuit, a DC-AC conversion circuit, and an output port of the inverter device; determining a maximum power point of the first photovoltaic cell based on taking an optimal operating voltage of a second photovoltaic cell as a desired output voltage of the DC-DC conversion circuit and based on the first sensing information, the optimal operating voltage representing a voltage output by the second photovoltaic cell associated with the maximum power point of the second photovoltaic cell, the second photovoltaic cell being coupled to the AC power grid or device via a second input port, an output side of the DC-DC conversion circuit, the DC-AC conversion circuit, and the output port of the inverter device; and generating a first control signal for the DC-DC conversion circuit based on the optimal operating voltage of the second photovoltaic cell and the determined maximum power point of the first photovoltaic cell.

[0018] In some embodiments of the present disclosure, the method further includes: obtaining second sensing information indicating an input voltage and current of the DC-AC conversion circuit; determining a maximum power point and an optimal operating voltage of the second photovoltaic cell based on the second sensing information; and generating a second control signal for the DC-AC conversion circuit based on the determined maximum power point of the second photovoltaic cell.

[0019] In some embodiments of the present disclosure, a time interval for generating the first control signal is smaller than a time interval for generating the second control signal.

[0020] In some embodiments of the present disclosure, obtaining first sensing information indicating the output voltage and current of the first photovoltaic cell includes: obtaining multiple sub-sensing information indicating the output voltage and current of multiple groups of photovoltaic cells in the first photovoltaic cell. Determining the maximum power point of the first photovoltaic cell includes: determining, for each DC-DC converter among the multiple DC-DC converters, an expected output voltage corresponding to the corresponding DC-DC converter based on the optimal operating voltage; and determining the maximum power point of the corresponding group of photovoltaic cells based on the corresponding sub-sensing information and the corresponding expected output voltage. Generating a first control signal for the DC-DC conversion circuit includes: generating, for each DC-DC converter among the multiple DC-DC converters, a control signal for the corresponding DC-DC converter based on the corresponding expected output voltage and the maximum power point of the group of photovoltaic cells corresponding to the corresponding DC-DC converter.

[0021] According to a fourth aspect of the present disclosure, a control device for an inverter apparatus is provided, the control device comprising: a processor; and a memory coupled to the processor, the memory having instructions stored therein, which, when executed by the processor, causes a controller to execute the method according to the third aspect.

[0022] According to a fifth aspect of the present disclosure, a computer-readable storage medium is provided, on which a computer program code is stored. When the computer program code is executed, the method according to the third aspect is executed.

[0023] According to a sixth aspect of the present disclosure, there is provided a computer program product tangibly stored on a non-transitory computer-readable medium and comprising machine-executable instructions which, when executed, cause a machine to perform the steps of the method according to the third aspect.

[0024] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the disclosure, nor is it intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and other objects, features and advantages of the present disclosure will become more apparent through a more detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present disclosure.

[0026] FIG1 shows a schematic circuit diagram of a photovoltaic system and an AC power grid or device according to an embodiment of the present disclosure.

[0027] FIG2 shows an external side view of an inverter device according to an embodiment of the present disclosure.

[0028] FIG3 shows a schematic circuit diagram of a photovoltaic system according to an embodiment of the present disclosure.

[0029] FIG4 shows a schematic circuit diagram of a photovoltaic system according to an embodiment of the present disclosure.

[0030] 5A and 5B are schematic circuit diagrams showing a DC-DC conversion circuit in an inverter device according to an embodiment of the present disclosure.

[0031] 6A and 6B are schematic circuit diagrams showing a two-stage circuit of a DC-AC conversion circuit in an inverter device according to an embodiment of the present disclosure.

[0032] FIG7 shows a schematic circuit diagram of a single-stage circuit of a DC-AC conversion circuit in an inverter device according to an embodiment of the present disclosure.

[0033] FIG8 shows a schematic circuit diagram of a photovoltaic system according to an embodiment of the present disclosure.

[0034] 9A and 9B show schematic circuit diagrams of a first input port of an inverter device and a DC-DC conversion circuit according to an embodiment of the present disclosure.

[0035] FIG10 shows a schematic flowchart of a method for controlling an inverter device according to an embodiment of the present disclosure.

[0036] FIG11 shows a schematic flowchart of a process of controlling an inverter device according to an embodiment of the present disclosure.

[0037] FIG12 shows a schematic diagram of a control device for controlling an inverter according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0038] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art. Those skilled in the art can derive alternative technical solutions from the following description without departing from the spirit and scope of protection of the present disclosure.

[0039] As used herein, the term "including" and its variations mean open inclusion, i.e., "including but not limited to." The term "or" means "and / or" unless otherwise stated. The term "based on" means "based, at least in part, on." The term "an example" or "an embodiment" means "at least one example embodiment." Other explicit and implicit definitions may be included below.

[0040] Embodiments of the present disclosure provide an improved photovoltaic inverter solution. In this improved solution, at least two power conversion circuits are disposed within the housing of the inverter device, and one of the at least two power conversion circuits is disposed between two input ports. Thus, the inverter device can receive output power from a first photovoltaic cell and a second photovoltaic cell of different voltage levels, perform power conversion, and directly provide the power to a subsequent AC grid or AC device. Furthermore, this improved solution can implement maximum power point tracking for both the first photovoltaic cell and the second photovoltaic cell, ensuring that both photovoltaic cells operate at the highest power generation efficiency. In some new photovoltaic modules, two different types of photovoltaic cells with significantly different output voltages are assembled in a single module, which presents difficulties in grid connection, particularly due to the lack of micro-inverter solutions that can directly connect a single such module to an AC grid or AC device. The disclosed solution enables photovoltaic modules with two different types of photovoltaic cells to be directly connected to the grid or to an AC load via a single inverter device, enabling independent power conversion and control for each photovoltaic module and each different type of cell within each module. This provides greater flexibility and reliability, saves power, reduces costs, and maximizes system efficiency.

[0041] FIG1 shows a schematic circuit diagram of a photovoltaic system 10 and an AC power grid or device 20 according to an embodiment of the present disclosure. As shown in FIG1 , the photovoltaic system 10 and the AC power grid or device 20 are coupled to each other, and the photovoltaic system 10 feeds the electrical energy generated by photovoltaic power generation to the AC power grid or device 20. For example, the AC power grid or device 20 may be an AC distribution network having a live wire L and a neutral wire N. In another example, the AC power grid or device 20 may be an AC bus that aggregates the electrical energy output by multiple photovoltaic systems or multiple photovoltaic modules for transmission to the outside. In yet another example, the AC power grid or device 20 may be an AC load that receives and consumes the AC power generated by the photovoltaic system 10. It will be understood that the AC power grid or device 20 may be an AC power network, AC device, or AC load of different levels or types, and the present disclosure is not limited thereto.

[0042] The photovoltaic system 10 includes a photovoltaic assembly 100. The photovoltaic assembly 100 includes a first photovoltaic cell 110 and a second photovoltaic cell 120. The first photovoltaic cell 110 and the second photovoltaic cell 120 can be assembled together, for example, by fastening components or other assembly means. Thus, the first photovoltaic cell 110 and the second photovoltaic cell 120 can form a single photovoltaic assembly. It is understood that the photovoltaic assembly 100 may also include other components or elements required to form the assembly, such as packaging materials, a support frame, etc. In one embodiment, the first photovoltaic cell 110 is located at the bottom of the photovoltaic assembly, and the second photovoltaic cell 120 is located at the top of the photovoltaic assembly. The second photovoltaic cell 120 has a wider bandgap than the first photovoltaic cell 110. The first photovoltaic cell 110 may include a crystalline silicon cell, and the second photovoltaic cell 120 may include a perovskite cell. Crystalline silicon cells are made of crystalline silicon materials, which have the advantages of high conversion efficiency, strong stability, and mature technology. Perovskite cells use perovskite structural materials as light-absorbing materials, which have the characteristics of low cost, high light absorption coefficient, long carrier diffusion length and adjustable band gap (for example, 1.17 to 2.8 eV), and high theoretical conversion efficiency. In one embodiment, the first photovoltaic cell 110 includes one or more crystalline silicon cells, and the second photovoltaic cell 120 includes one or more perovskite cells. Generally speaking, the output voltage of the first photovoltaic cell 110 is lower than 40V or 50V, while the output voltage of the second photovoltaic cell 120 is much higher than that of the first photovoltaic cell 110 and can be as high as 200V. In one embodiment, the first photovoltaic cell 110 and the second photovoltaic cell 120 are assembled together in a vertical stack, and the two are optically coupled and electrically independent of each other. For example, when the first photovoltaic cell 110 is a crystalline silicon cell and the second photovoltaic cell 120 is a perovskite cell, since the perovskite cell can be adjusted to a bandgap of appropriate width to enhance the absorption and utilization efficiency of short-wave light (generally mainly absorbing high-energy photons with a wavelength less than 800nm) and have a greater transmittance, the second photovoltaic cell 120 (specially absorbing low-energy photons with a wavelength less than 1100nm) can be stacked on top of the first photovoltaic cell 110. For example, a sheet-shaped perovskite cell and a sheet-shaped crystalline silicon cell are stacked together in a stacked manner, so that the two types of photovoltaic cells are placed in the same photovoltaic module. By combining cells with different bandgaps, segmented utilization of the solar spectrum is achieved, achieving more efficient light absorption and conversion, thereby effectively improving power conversion efficiency, reducing energy loss and not occupying additional floor space. In one example, the photovoltaic module 100 in the photovoltaic system 10 can be arranged alone in a small place such as a balcony, or arranged together with other photovoltaic modules 100 in a large place such as a roof. The present disclosure does not limit the application location of the photovoltaic system 10.

[0043] The photovoltaic system 10 further includes an inverter device 200, which is coupled between the photovoltaic assembly 100 and the AC power grid or device 20. For example, the inverter device 200 may be a micro-inverter device that couples a single photovoltaic assembly 100 to the AC power grid or device 20, and may be mounted on the back of the frame of the photovoltaic assembly 100 or near the photovoltaic assembly 100. The inverter device 200 may receive power from both the first photovoltaic cell 110 and the second photovoltaic cell 120 of the photovoltaic assembly 100, and convert the power into AC power for output to the AC power grid or device 20.

[0044] FIG2 illustrates an exterior view of an inverter device 200 according to an embodiment of the present disclosure. As shown in FIG2 , the inverter device 200 includes a housing 210, a first input port 220 adapted to couple to the first photovoltaic cell 110, and a second input port 230 adapted to couple to the second photovoltaic cell 210. Furthermore, the inverter device 200 includes an output port 240 adapted to couple to an AC power grid or device 20. For example, the first input port 220, the second input port 230, and the output port 240 may be provided with terminals or connectors for electrical connection. Through the first input port 220, the second input port 230, and the output port 240, the circuitry within the housing 210 can be electrically coupled or connected to the photovoltaic assembly 100 and the AC power grid or device 20, thereby transmitting the power generated by the photovoltaic assembly 100 to the AC power grid or device 20. It will be appreciated that the inverter device 200 may include other suitable components on or outside the housing 210, such as heat dissipation components and mounting components for securing the inverter device 200.

[0045] FIG3 shows a schematic circuit diagram of a photovoltaic system 10 according to an embodiment of the present disclosure. FIG3 illustrates the internal circuitry of the inverter device 200 in greater detail than in FIG1 and FIG2 . As shown in FIG3 , the inverter device 200 includes a DC-DC converter circuit 250 located within a housing 210 . The DC-DC converter circuit 250 is coupled to a first input port 220 on its input side and to a second input port 230 on its output side. Specifically, the first input port 220 and the second input port 230, each coupled to a different photovoltaic cell, input two different DC voltages into the inverter device 210. The DC-DC converter circuit 250, coupled between the two input ports, converts the voltages to convert one of the two input voltages to be the same as or similar to the other input voltage. This eliminates the voltage difference between the two input voltages, allowing the two inputs to be combined into one output for subsequent circuitry. In one embodiment, the DC-DC converter circuit 250 includes a DC boost (BOOST) converter. For example, if the first photovoltaic cell 110 is a crystalline silicon cell and is coupled to the first input port 220, and the second photovoltaic cell 120 is a perovskite cell and is coupled to the second input port 230, the first photovoltaic cell 110 will output a relatively low voltage (e.g., approximately 40V or 50V) to the first input port 220, while the second photovoltaic cell 120 will output a higher voltage (e.g., approximately 200V) to the second input port 230. The DC-DC conversion circuit 250, acting as a BOOST converter, can boost the lower voltage input from the crystalline silicon cell via the first input port 220 to a voltage substantially close to the higher voltage output by the second photovoltaic cell 120. In another embodiment, the DC-DC conversion circuit 250 includes a DC step-down (BUCK) converter. For example, if the first photovoltaic cell 110 is a crystalline silicon cell and is coupled to the second input port 230, and the second photovoltaic cell 120 is a perovskite cell and is coupled to the first input port 220 (i.e., the connections of the two photovoltaic cells and the two input ports in FIG3 are interchanged), the first photovoltaic cell 110 will output a relatively low voltage (e.g., approximately 40V or 50V) to the second input port 230, while the second photovoltaic cell 120 will output a higher voltage (e.g., approximately 200V) to the first input port 220. The DC-DC converter circuit 250, acting as a buck converter, can step down the higher voltage input from the perovskite cell via the first input port 220 to a voltage substantially close to the output voltage of the first photovoltaic cell 110. The DC-DC converter circuit 250 employing a buck circuit is suitable for scenarios where the output power of the low-voltage photovoltaic cell is relatively high, while the output power of the high-voltage photovoltaic cell is relatively low.However, compared to the solution using a step-down circuit, the solution using a boost circuit in the DC-DC conversion circuit 250 is more advantageous because the boost circuit allows the high-voltage input to directly enter the subsequent stage, and the low-voltage input is gradually increased to a high voltage, thereby increasing the operating voltage of the subsequent circuit and thereby reducing the operating current, which helps to minimize the power consumption of the photovoltaic system and its inverter device.

[0046] According to an embodiment of the present disclosure, the inverter device 200 includes a DC-AC converter circuit 260. The DC-AC converter circuit 260 is located within the housing 210 and is coupled to the second input port 230 on its input side and to the output port 240 on its output side. Specifically, the DC-AC converter circuit 260 can perform appropriate power conversion on the photovoltaic DC power from the second input port 230 and the photovoltaic DC power from the first input port 220, which has been converted by the DC-DC converter circuit 250, to generate the AC power required by the AC grid or the device 20.

[0047] According to an embodiment of the present disclosure, the inverter device 200 further includes a controller 270. The controller 270 is coupled to the DC-DC conversion circuit 250 and the DC-AC conversion circuit 260, and can control the DC-DC conversion circuit 250 and the DC-AC conversion circuit 260. As an example, the controller 270 can be implemented in the form of a controller with computing and processing capabilities, for example, the controller 270 can be a microcontroller unit (MCU) or a digital signal processor (DSP). In addition, the controller 270 can also be implemented in the form of an analog circuit and / or a digital circuit, or in a combination of the above multiple forms. The controller 270 can obtain sensing information related to electrical quantities (e.g., voltage, current, etc.) of the DC-DC converter circuit 250, the DC-AC converter circuit 260, the first photovoltaic cell 110, and the second photovoltaic cell 120 from a sensing device, and thereby control the power switching devices in the DC-DC converter circuit 250 and the DC-AC converter circuit 260 based on the sensing information. For example, the controller 270 can send pulse-width modulation (PWM) signals to the power switching devices to cause the DC-DC converter circuit 250 and the DC-AC converter circuit 260 to perform the desired power conversion operation. In some embodiments, the controller 270 can control the DC-AC converter circuit 260 to use the optimal operating voltage associated with the maximum power point of the second photovoltaic cell 120 as the desired output voltage and track the maximum power point of the second photovoltaic cell 120, and control the DC-DC converter circuit 250 to track the maximum power point of the first photovoltaic cell 110. As an example, the controller 270 may utilize the DC-DC conversion circuit 250 and the DC-AC conversion circuit 260 to perform maximum power point tracking (MPPT) on the first photovoltaic cell 110 and the second photovoltaic cell 120 .The controller 270 can use the MPPT algorithm to determine the maximum power point of the first photovoltaic cell 110 and the second photovoltaic cell 120 in the current state based on the sensing information, and can adjust the output voltage and current of the first photovoltaic cell 110 and the second photovoltaic cell 120 respectively by controlling the DC-DC conversion circuit 250 and the DC-AC conversion circuit 260. Before tracking the maximum power point of the first photovoltaic cell 110, the maximum power point of the second photovoltaic cell 120 and the optimal operating voltage of the second photovoltaic cell 120 can be determined first, so that the optimal operating voltage can be used as the desired output voltage of the DC-DC conversion circuit 250, and based on this, the maximum power point of the first photovoltaic cell 110 is tracked, thereby making both the first photovoltaic cell 110 and the second photovoltaic cell 120 operate at the maximum power point to output the maximum power in the current state. In this way, not only can the power output of two photovoltaic cells with large voltage differences in a single photovoltaic module be received simultaneously, but it can also ensure that both photovoltaic cells operate at maximum output power when environmental factors such as ambient temperature and light intensity change. This effectively improves the power generation efficiency of the photovoltaic system and its photovoltaic modules and reduces the cost of photovoltaic power generation. It also helps to reduce the loss of photovoltaic modules and extend their service life.

[0048] It can be understood that in addition to the circuits and components shown in Figure 3, the inverter device 200 can also be provided with other circuits or components as needed. For example, electromagnetic interference (EMI) filters can be respectively provided between the first input port 220 and the input side of the DC-DC conversion circuit 250, between the second input port 220 and the output side of the DC-DC conversion circuit 250, and / or between the output port 240 and the output side of the DC-AC conversion circuit 260.

[0049] FIG4 shows a schematic circuit diagram of a photovoltaic system 10 according to another embodiment of the present disclosure. Unlike FIG3 , FIG4 further illustrates the implementation of a DC-AC conversion circuit 260. As shown in FIG4 , the DC-AC conversion circuit 260 includes a DC-DC converter 261 and a DC-AC converter 262 coupled in series. Specifically, the DC-AC conversion circuit 260 may have a two-stage circuit, wherein the first stage further boosts the DC voltage to ensure a sufficiently high voltage level, and the second stage converts the DC power into AC power, thereby ensuring that the power output by the inverter 200 is suitable for transmission to the AC grid or device 20. In one embodiment, the controller 270 may control the DC-DC converter 261 in the DC-AC conversion circuit 260 to track the maximum power point of the second photovoltaic cell 120. Specifically, in the two-stage DC-AC conversion circuit 260, the controller 270 may achieve MPPT operation for the second photovoltaic cell 120 by controlling only the DC-DC converter 261 in the first stage. Alternatively, the DC-AC conversion circuit 260 may be a single-stage circuit, and the single-stage circuit may implement a boost inverter operation and / or an MPPT operation. In one embodiment, the DC-DC converter 261 in the DC-AC conversion circuit 260 or the single-stage DC-AC conversion circuit 260 may be provided with an isolation transformer to electrically isolate the photovoltaic assembly 100 from the AC grid or the device 20 on the high-voltage side, thereby ensuring the safety of the equipment and personnel.

[0050] Figures 5A and 5B illustrate schematic circuit diagrams of a DC-DC converter circuit 250 in an inverter device 200 according to an embodiment of the present disclosure. As shown in Figure 5A, the DC-DC converter circuit 250 may be a BOOST converter and includes an inductor L1, power switches Q1 and Q2, and capacitors C1 and C2. When the voltage at the second input port 230 is higher than the voltage at the first input port 220, the BOOST converter boosts the voltage at the first input port 220 and performs maximum power point tracking on the photovoltaic cell coupled to the first input port 220. For example, the first input port 220 is coupled to one side of the BOOST converter's capacitor C1, and one side of the capacitor C2 is coupled to the second input port 230 and the input side of the DC-AC converter circuit 260. The controller 270 can achieve boost and MPPT operations by switching the power switch Q1 on and off (e.g., in a PWM control mode). As shown in FIG5B , the DC-DC converter circuit 250 can be a buck converter having the same components and topology as the boost converter of FIG5A (the difference from FIG5A is that the input and output sides are interchanged). When the voltage at the first input port 220 is higher than the voltage at the second input port 230, the buck converter steps down the voltage at the first input port 220 and performs maximum power point tracking on the photovoltaic cell coupled to the first input port 220. For example, the first input port 220 is coupled to one side of the buck converter's capacitor C2, and one side of the capacitor C1 is coupled to the second input port 230 and the input side of the DC-AC converter circuit 260. The controller 270 can achieve voltage reduction and MPPT operation by switching the power switch Q2 on and off (e.g., in PWM control mode). It will be understood that the above implementation of the DC-DC converter circuit 250 is merely exemplary, and other components and elements may be added, or some components and elements may be removed or replaced, as needed. In addition, in addition to the BOOST and BUCK circuits, the DC-DC conversion circuit 250 may also adopt other types of DC boost or buck circuits that have been developed or will be developed in the future.

[0051] Figures 6A and 6B illustrate schematic circuit diagrams of two-stage circuits 261 and 262 of a DC-AC converter circuit 260 in an inverter device 200 according to an embodiment of the present disclosure. As shown in Figure 6A, the DC-DC converter 261 can be a flyback DC boost converter. For example, the flyback DC boost converter includes a power switch Q3, an isolation transformer T1, a diode D1, and capacitors C3 and C4. The flyback DC boost converter boosts the input voltage and performs maximum power point tracking on the photovoltaic cell coupled to the second input port 230. For example, the second input port 230 and the output side of the DC-DC conversion circuit 250 are coupled to one side of capacitor C3 of the flyback boost converter, and one side of capacitor C4 is coupled to the subsequent DC-AC converter 262. The controller 270 can receive sensing information (e.g., the current on the source side of the power switch Q3, the output current of the flyback converter, and sensed electrical quantities related to the MPPT operation) and implement boost and MPPT operations by switching the power switch Q3 on and off (e.g., in a PWM control mode). Furthermore, the DC-DC converter 261, as a flyback DC boost converter, can also employ active clamping technology and / or voltage doubling rectification technology to improve the converter's conversion efficiency and reduce voltage stress on the power switch. As shown in FIG6B , the DC-AC converter 262 can be a full-bridge inverter. For example, the full-bridge inverter includes power switches Q4, Q5, Q6, and Q7, an inductor L2, and capacitors C5 and C6. The full-bridge inverter inverts the input DC power. For example, the output side of the DC-DC converter 261 is coupled to one side of the capacitor C5 of the full-bridge inverter, and one side of the capacitor C6 is coupled to the output port 240, and the controller 270 can receive sensing information (such as the inverting current output by the full-bridge arm) and realize the inversion operation by performing on and off operations (such as PWM control mode) on the power switching devices Q4, Q5, Q6 and Q7.

[0052] FIG7 shows a schematic circuit diagram of a single-stage circuit of a DC-AC conversion circuit 260 in an inverter device 200 according to an embodiment of the present disclosure. As shown in FIG7 , the DC-AC conversion circuit 260 includes an LLC-based inverter. For example, the LLC-based inverter can be an LLC-based cycloconverter, which includes power switching devices Q8 to Q15, an isolation transformer T2, an inductor L3, and capacitors C7 to C10. The LLC-based inverter boosts the input voltage and inverts the DC power, and performs maximum power point tracking on the photovoltaic cell coupled to the second input port 230. For example, the output side of the DC-DC conversion circuit 250 and the second input port 230 are coupled to one side of the capacitor C7 of the LLC-based inverter, and one side of the capacitor C10 is coupled to the output port 240, and the controller 270 can receive sensing information (such as the inverter current output by the isolation transformer T2 and the sensed electrical quantities related to the MPPT operation) and realize boost, inversion and MPPT operations by performing on and off operations (such as PWM control mode) on the power switching devices Q8 to Q15.

[0053] It is understood that the above implementation of the DC-AC conversion circuit 260 is merely exemplary, and other components and elements may be added, or some components and elements may be removed or replaced, as needed. Furthermore, in addition to a flyback converter, a full-bridge inverter, and an LLC-based inverter circuit, the DC-AC conversion circuit 260 may also employ other types of DC-AC conversion circuits that have already been developed or will be developed in the future.

[0054] FIG8 shows a schematic circuit diagram of a photovoltaic system 10 according to another embodiment of the present disclosure. The difference from FIG3 is that the first input port 220 in FIG8 includes multiple sub-input ports, such as sub-input ports 220-1, 220-2, and 220-3, and the DC-DC conversion circuit 250 includes multiple DC-DC converters, such as DC-DC converters 250-1, 250-2, and 250-3. The multiple DC-DC converters 250-1, 250-2, and 250-3 are coupled to the multiple sub-input ports 220-1, 220-2, and 220-3 on their input sides, respectively, and are connected in series with each other on their output sides. In addition, the first photovoltaic cell 110 includes multiple groups of photovoltaic cells, and the multiple sub-input ports 220-1, 220-2, and 220-3 are coupled to the multiple groups of photovoltaic cells, respectively.

[0055] As an example, when the first photovoltaic cell 110 is a photovoltaic cell such as a crystalline silicon cell, the first photovoltaic cell 110 may be provided with multiple photovoltaic cells, and may be divided into multiple groups, each group of cells containing at least one cell. In conventional solutions, photovoltaic modules need to be equipped with a distribution box to output the direct current generated by the photovoltaic module to subsequent circuits such as inverters. The distribution box is usually equipped with a bypass diode in parallel for each group of cells in the multiple groups of cells. These bypass diodes can bypass the corresponding group of cells in the photovoltaic module under certain circumstances. For example, if a group of cells is blocked or partially damaged, in order to prevent damage to this group of cells due to the hot spot effect, the bypass diode connected in parallel with this group of cells can bypass this group of cells, thereby ensuring that the other cells can still operate normally. However, this bypass diode will cause the bypassed group of cells to stop outputting power as a whole, even if the group of cells is only partially blocked or partially damaged. In addition, the distribution box and its bypass diodes are relatively easy to damage and malfunction components in the photovoltaic system. Therefore, during the useful life of the photovoltaic system and its photovoltaic modules, the distribution box and its bypass diodes often need to be repaired and replaced. By providing multiple sub-input ports and multiple DC-DC converters in the inverter device 200, the generated power of each group of photovoltaic cells in the multiple groups of photovoltaic cells can be directly regulated and output. For example, when a group of photovoltaic cells is blocked, the corresponding DC-DC converter can regulate the voltage of the output of the group of photovoltaic cells and output it to the outside without bypassing it. As a result, it is no longer necessary to set up traditional bypass diodes and distribution boxes for photovoltaic modules. In this way, not only are the distribution boxes and their bypass diodes with a high failure rate removed, thereby improving the reliability of the system, but it also ensures that the blocked or partially damaged cell groups can still output a certain amount of power, thereby improving energy utilization efficiency.

[0056] In some embodiments, controller 270 can control a corresponding DC-DC converter among the plurality of DC-DC converters 250-1, 250-2, and 250-3 to track the maximum power point of a group of photovoltaic cells corresponding to the corresponding DC-DC converter. For example, controller 270 can control DC-DC converter 250-1 based on the maximum power point of a group of photovoltaic cells coupled to sub-input port 220-1, so that DC-DC converter 250-1 adjusts the output voltage and current of the group of photovoltaic cells to the maximum power point. In this way, independent MPPT operation can be performed on each group of photovoltaic cells in first photovoltaic cell 110, thereby achieving greater flexibility and higher power generation efficiency.

[0057] In another embodiment, the plurality of DC-DC converters 250-1, 250-2, and 250-3 may be connected to the output port 230 in parallel on their output sides, or may be connected to the output port 230 in a mixed series and parallel manner (e.g., some converters are connected in series on the output side and then connected in parallel with the remaining converters on the output side, or some converters are connected in parallel on the output side and then connected in series with the remaining converters on the output side). However, compared to the parallel and series-parallel methods, coupling the plurality of DC-DC converters in series is more advantageous because the series method ensures that each DC-DC converter does not need to boost the voltage to an excessively high level, thereby maintaining a relatively moderate operating duty cycle of each DC-DC converter, making it easier to obtain a higher output voltage, thereby improving overall efficiency.

[0058] Figures 9A and 9B illustrate schematic circuit diagrams of the first input port 220 of the inverter device 200 and the DC-DC converter circuit 250 according to an embodiment of the present disclosure. As shown in Figure 9A , the multiple DC-DC converters 250-1 through 250-3 of the DC-DC converter circuit 250 are BOOST converter circuits, and are connected in series at their output sides to output power. As an example, the DC-DC converter 250-1 includes an inductor L4-1, power switching devices Q16-1 and Q17-1, and capacitors C11-1 and C12-1, and is coupled to the sub-input port 220-1 on one side of the capacitor C11-1; the DC-DC converter 250-2 includes an inductor L4-2, power switching devices Q16-2 and Q17-2, and capacitors C11-2 and C12-2, and is coupled to the sub-input port 220-2 on one side of the capacitor C11-2; and the DC-DC converter 250-3 includes an inductor L4-3, power switching devices Q16-3 and Q17-3, and capacitors C11-3 and C12-3, and is coupled to the sub-input port 220-3 on one side of the capacitor C11-3. Controller 270 controls power switches Q17-1, Q17-2, and Q17-3 (e.g., in PWM control mode) to perform boost and MPPT operations on the battery cell groups coupled to sub-input ports 220-1, 220-2, and 220-3, respectively. Unlike FIG9A , FIG9B illustrates a plurality of DC-DC converters 250-1 to 250-3 connected in parallel at their outputs to output power. The components and other connections in FIG9B are similar to those in FIG9A and are therefore not further described.

[0059] Furthermore, the number of bypass diodes in a conventional power distribution box is typically three, and therefore the number of the multiple sub-input ports 220-1, 220-2, and 220-3 and the multiple DC-DC converters 250-1, 250-2, and 250-3 shown in FIG8 , FIG9A , and FIG9B is also three. However, the number of sub-input ports and corresponding DC-DC converters in the inverter device 200 may be greater or lesser depending on actual circumstances.

[0060] FIG10 is a schematic flow chart of a method 1000 for controlling an inverter device 200 according to an embodiment of the present disclosure. The method 1000 can be implemented in the scenarios shown in FIG1 , FIG3 , FIG4 , and FIG8 , and executed by the controller 270. For discussion purposes, the method 1000 will be described with reference to FIG1 through FIG9 .

[0061] At block 1001, controller 270 obtains first sensed information indicating the output voltage and current of a first photovoltaic cell 110. First photovoltaic cell 110 is coupled to an AC power grid or device 20 via first input port 220, DC-DC converter circuit 250, DC-AC converter circuit 260, and output port 240 of inverter device 200. By way of example, a sensing device may be provided on the connection line between first photovoltaic cell 110 and DC-DC converter circuit 150, for example, near first input port 220, to sense the voltage and current generated and output by first photovoltaic cell 110. Controller 270 may receive the sensed information from the sensing device, thereby understanding the current output power of first photovoltaic cell 110 and determining the maximum power point of first photovoltaic cell 110 in its current state.

[0062] In some embodiments of the present disclosure, the controller 270 obtains multiple sub-sensing information indicating the output voltage and current of multiple groups of photovoltaic cells in the first photovoltaic cell 110. As an example, in the photovoltaic system 10 shown in FIG8 , sensing devices can be provided in the current path between each group of cells in the first photovoltaic cell 110 and the corresponding DC-DC converter, for example, near sub-input ports 220-1, 220-2, and 220-3, to sense the voltage and current generated and output by each group of cells. The controller 270 can receive multiple sub-sensing information from these sensing devices to determine the current output power of each group of cells in the first photovoltaic cell 110. This sub-sensing information helps determine the maximum power point of each group of cells in the first photovoltaic cell 110 in its current state.

[0063] At block 1002, controller 270 determines the maximum power point of first photovoltaic cell 110 based on the optimal operating voltage of the second photovoltaic cell as the desired output voltage of DC-DC converter circuit 250 and based on first sensing information. The optimal operating voltage represents the voltage output by second photovoltaic cell 120 associated with the maximum power point of second photovoltaic cell 120. Second photovoltaic cell 120 is coupled to AC power grid or device 20 via second input port 230 of inverter device 200, the output side of DC-DC converter circuit 250, DC-AC converter circuit 260, and output port 240. For example, before controlling DC-DC converter circuit 250, controller 270 may determine or obtain the maximum power point of second photovoltaic cell 120 in advance and determine the optimal operating voltage associated with the maximum power point. Specifically, when second photovoltaic cell 120 uses the optimal operating voltage as the output voltage of the cell, second photovoltaic cell 120 can output maximum power. This optimal operating voltage is further used as the desired output voltage of the output side of DC-DC converter circuit 250. For example, after obtaining first sensed information indicating the output voltage and current of the first photovoltaic cell 110 and determining the desired output voltage of the output side of the DC-DC converter circuit 250, the controller 270 can utilize an MPPT algorithm to determine and track the maximum power point of the first photovoltaic cell 110. The MPPT algorithm may include, for example, a perturbation-and-observation method, an incremental conductance method, and may also include related MPPT algorithms developed in the future. In this way, the output side voltage of the DC-DC converter circuit 250 can be fixed at a certain voltage, making it possible to determine the maximum power point of the first photovoltaic cell 110 (if the output side voltage of the DC-DC converter circuit 250 is in a changing state, the maximum power point of the first photovoltaic cell 110 cannot be determined). At the same time, since the second photovoltaic cell 120 is directly coupled to the output side of the DC-DC converter circuit 250 via the second output port 230, it can also ensure that the DC-DC converter circuit 250 can adjust the voltage of its output side to match the voltage of the maximum power point of the second photovoltaic cell 120, thereby facilitating maximum power point tracking for the second photovoltaic cell 120.

[0064] In some embodiments of the present disclosure, for each of the plurality of DC-DC converters 250-1, 250-2, and 250-3, the controller 270 determines a desired output voltage corresponding to the corresponding DC-DC converter based on the optimal operating voltage, and determines a maximum power point of the corresponding group of photovoltaic cells based on the corresponding sub-sensing information and the corresponding desired output voltage. As an example, in the photovoltaic system 10 shown in FIG8 , the plurality of DC-DC converters 250-1, 250-2, and 250-3 are coupled to each other in series on the output side. Therefore, the controller 270 can decompose the optimal operating voltage into the desired output voltages of the respective DC-DC converters in appropriate proportions to ensure that the sum of the multiple desired output voltages equals the optimal operating voltage. For example, if the optimal operating voltage is 180V, which means that the total desired output voltage of the plurality of DC-DC converters 250-1, 250-2, and 250-3 is 180V, then the desired output voltage of each of the three DC-DC converters 250-1, 250-2, and 250-3 can be set to 60V. Thus, controller 270 can determine the desired output voltage of each DC-DC converter 250-1, 250-2, and 250-3 at the output side. Furthermore, after determining the desired output voltage of each DC-DC converter and obtaining voltage and current information of the cell groups corresponding to each DC-DC converter, controller 270 can use the MPPT algorithm to determine the maximum power point of each group of photovoltaic cells.

[0065] Alternatively, when multiple DC-DC converters 250-1, 250-2, and 250-3 are coupled to each other in parallel or in a mixed series-parallel manner on their output sides, the controller 270 can determine the expected output voltage of each DC-DC converter in the DC-DC conversion circuit 250 in a similar manner, wherein the expected output voltage of each DC-DC converter 250-1, 250-2, and 250-3 in the parallel manner is the same as the optimal operating voltage of the second photovoltaic cell 120, and the expected output voltage of each DC-DC converter 250-1, 250-2, and 250-3 in the series-parallel manner can be determined by decomposing the optimal operating voltage according to the actual connection method, and it is necessary to ensure that the total output voltage on the output side of each DC-DC converter is equal to the optimal operating voltage.

[0066] At block 1003 , the controller 270 generates a first control signal for the DC-DC converter circuit 250 based on the optimal operating voltage of the second photovoltaic cell 120 and the determined maximum power point of the first photovoltaic cell 110 .

[0067] As an example, the controller 270 can determine the desired input voltage and current for the DC-DC converter circuit 250 based on the determined maximum power point for the first photovoltaic cell 110. Since the input voltage and current of the DC-DC converter circuit 250 are effectively the output voltage and current of the first photovoltaic cell 110, when the DC-DC converter circuit 250 adjusts its input voltage and current to the desired input voltage and current associated with the maximum power point of the first photovoltaic cell 110, it ensures that the first photovoltaic cell 110 operates at its maximum power point, thereby achieving maximum power point tracking for the first photovoltaic cell 110. Furthermore, the controller 270 also determines the optimal operating voltage of the second photovoltaic cell 120 as the desired output voltage of the DC-DC converter circuit 250. Consequently, the controller 270 can generate a first control signal to control the power switch device (e.g., Q1 or Q2) in the DC-DC converter circuit 250 to perform on and off operations, thereby adjusting both the input and output sides of the DC-DC converter circuit 250 to the desired voltage and current levels. In this way, not only is the maximum power point tracking of the first photovoltaic cell 110 achieved, but also, because the voltage on the output side of the DC-DC conversion circuit 250 matches the voltage of the maximum power point of the second photovoltaic cell 120, it also helps to achieve the maximum power point tracking of the second photovoltaic cell 120.

[0068] In some embodiments of the present disclosure, for each of the plurality of DC-DC converters 250-1, 250-2, and 250-3, a controller 270 generates a control signal for the corresponding DC-DC converter based on the corresponding desired output voltage and the maximum power point of the group of photovoltaic cells corresponding to the corresponding DC-DC converter. As an example, in the photovoltaic system 10 shown in FIG8 , the plurality of DC-DC converters 250-1, 250-2, and 250-3 are coupled in series on the output side. The controller 270 decomposes the optimal operating voltage of the second photovoltaic cell 120 into the desired output voltages of each DC-DC converter according to appropriate proportions, and ensures that the sum of the multiple desired output voltages equals the optimal operating voltage. Furthermore, the controller 270 can determine the desired input voltage and current of each DC-DC converter 250-1, 250-2, and 250-3 based on the determined maximum power point for each group of cells, which is also the desired output voltage and current of each group of photovoltaic cells of the first photovoltaic cell 110. After determining the desired output voltage and the desired input voltage and current of each DC-DC converter, controller 270 can, based on this, issue control signals to the power switches (e.g., Q17-1, Q17-2, and Q17-3) of each DC-DC converter 250-1, 250-2, and 250-3 to adjust the input and output sides of each DC-DC converter 250-1, 250-2, and 250-3 to the desired voltage and / or current levels. For example, controller 270 can generate control signals for the power switches of DC-DC converter 250-1 based on the desired input voltage and current and the desired output voltage of DC-DC converter 250-1. This enables maximum power point tracking for each group of photovoltaic cells in first photovoltaic cell 110 and helps second photovoltaic cell 120 operate at its maximum power point.

[0069] FIG11 is a schematic flow chart of a process 1100 for controlling the inverter device 200 according to an embodiment of the present disclosure. Process 1100 may be an additional process of method 1000, wherein blocks 1101 and 1102 of process 1100 need to be executed before block 1002 in FIG10 to facilitate determining the optimal operating voltage required by block 1002. In addition, each block in process 1100 may be executed independently of each block in FIG10.

[0070] At block 1101, controller 270 obtains second sensed information indicating the input voltage and current of DC-AC converter circuit 260. For example, a sensing device may be provided on the input side of DC-AC converter circuit 260 or on a nearby connecting line to sense the voltage and current. Controller 270 may, for example, obtain the second sensed information from the provided sensing device to determine the maximum power point of second photovoltaic cell 120 in its current state.

[0071] At block 1102, based on the second sensing information, controller 270 determines the maximum power point of second photovoltaic cell 120 and the aforementioned optimal operating voltage. For example, controller 270 may utilize an MPPT algorithm based on the second sensing information to calculate and determine the maximum power point of second photovoltaic cell 120 in its current state. Once the maximum power point is determined, the output voltage of the second photovoltaic cell at the maximum power point is also determined. This voltage is used as the optimal operating voltage of second photovoltaic cell 120 and is then used to control DC-DC converter circuit 250 at block 1003.

[0072] At block 1103, the controller 270 generates a second control signal for the DC-AC conversion circuit 260 based on the determined maximum power point of the second photovoltaic cell 120. For example, the controller 270 may control the DC-AC conversion circuit 260, or the DC-DC converter 261 within the DC-AC conversion circuit 260, to ensure that the voltage at the input side of the DC-AC conversion circuit 260 remains at the voltage of the maximum power point (i.e., the optimal operating voltage), thereby enabling the second photovoltaic cell 120 to operate at the maximum power point in its current state to achieve MPPT.

[0073] In some embodiments of the present disclosure, the time interval at which controller 270 generates the first control signal is shorter than the time interval at which it generates the second control signal. Specifically, the second control signal generated by controller 270 is used to control DC-AC converter circuit 260 to perform maximum power point tracking for the second photovoltaic cell 120, while the first control signal generated by controller 270 is used to control DC-DC converter circuit 250 to perform maximum power point tracking for the first photovoltaic cell 120. As discussed above, controlling DC-DC converter circuit 250 to perform maximum power point tracking for the first photovoltaic cell 110 is based on determining the optimal operating voltage of the second photovoltaic cell 120 and controlling DC-AC converter circuit 260 to adjust the output voltage of the second photovoltaic cell 120. Therefore, maximum power point tracking for the second photovoltaic cell 120 can be configured to be performed more slowly over a longer period, while maximum power point tracking for the first photovoltaic cell 110 can be configured to be performed more quickly over a shorter period. In one example, the duration of the long period can be an integer multiple of the duration of the short period. For example, the long cycle may be 1 second, and the short cycle may be 100 milliseconds, that is, one MPPT operation cycle for the second photovoltaic cell 120 may correspond to 10 MPPT operation cycles for the first photovoltaic cell 110. In this way, it is possible to ensure that the DC-DC conversion current 250 can track the maximum power point of the first photovoltaic cell 110 as quickly as possible through multiple MPPT operations in a relatively short period of time, without having to wait for tracking of the second photovoltaic cell 120, thereby improving the overall efficiency of the system.

[0074] FIG12 shows a schematic diagram of a control device 1200 for controlling an inverter device 200 according to an embodiment of the present disclosure. The control device 1200 can be implemented as the controller 270 in FIG3 , FIG4 , and FIG8 , and can implement the methods and processes in FIG10 and FIG11 . As shown in FIG12 , the control device 1200 may include a processor 1210 and a memory 1220 coupled to the processor 1210. The memory 1220 has instructions stored therein that, when executed by the processor 1210, cause the controller 1200 to perform the methods and processes in FIG10 and FIG11 .

[0075] Those skilled in the art will appreciate that the various steps of the method disclosed above can be implemented by a general-purpose computing device. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Alternatively, they can be implemented using program code executable by a computing device, which can then be stored in a storage device and executed by the computing device. Alternatively, they can be fabricated into separate integrated circuit modules, or multiple modules or steps can be fabricated into a single integrated circuit module for implementation. Thus, the present disclosure is not limited to any particular combination of hardware and software.

[0076] It should be understood that although the detailed description above mentions several devices or sub-devices of a device, this division is merely exemplary and not mandatory. In fact, according to embodiments of the present disclosure, the features and functions of two or more devices described above may be embodied in a single device. Conversely, the features and functions of a single device described above may be further divided and embodied by multiple devices.

[0077] The foregoing description is merely an optional embodiment of the present disclosure and is not intended to limit the present disclosure. Those skilled in the art will readily appreciate that the present disclosure is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present disclosure shall be included within the scope of protection of the present disclosure.

Claims

1. An inverter device (200), comprising: A housing (210); A first input port (220), adapted to be coupled to a first photovoltaic cell (110); A second input port (230), adapted to be coupled to a second photovoltaic cell (120) different from the first photovoltaic cell (110); An output port (240), adapted to be coupled to an AC grid or device (20); A DC-DC conversion circuit (250), located within the housing (210), the DC-DC conversion circuit (250) being coupled to the first input port (220) at its input side and to the second input port (230) at its output side; A DC-AC conversion circuit (260), located within the housing (210), the DC-AC conversion circuit (260) being coupled to the second input port (230) at its input side and to the output port (240) at its output side; and A controller (270), coupled to the DC-DC conversion circuit (250) and the DC-AC conversion circuit (260), and configured to control the DC-DC conversion circuit (250) and the DC-AC conversion circuit (260).

2. The inverter device (200) according to claim 1, wherein the controller (270) is configured to control the DC-AC conversion circuit (260) to track the maximum power point of the second photovoltaic cell (120), and control the DC-DC conversion circuit (250) to use the optimal operating voltage associated with the maximum power point of the second photovoltaic cell (120) as the desired output voltage and track the maximum power point of the first photovoltaic cell (110).

3. The inverter device (200) according to claim 1, wherein the DC-AC conversion circuit (260) includes a series-coupled DC-DC converter (261) and a DC-AC converter (262), and wherein the controller (270) is configured to control the DC-DC converter (261) in the DC-AC conversion circuit (260) to track the maximum power point of the second photovoltaic cell (120), and control the DC-DC conversion circuit (250) to use the optimal operating voltage associated with the maximum power point of the second photovoltaic cell (120) as the desired output voltage and track the maximum power point of the first photovoltaic cell (110).

4. The inverter device (200) according to claim 1, wherein the first input port (220) includes a plurality of sub-input ports (220-1, 220-2, 220-3), and The DC-DC conversion circuit (250) includes a plurality of DC-DC converters (250-1, 250-2, 250-3), and the plurality of DC-DC converters (250-1, 250-2, 250-3) are respectively coupled to the plurality of sub-input ports (220-1, 220-2, 220-3) at their input sides, and are connected in series with each other, in parallel with each other, or in series and in parallel with each other at their output sides.

5. The inverter device (200) according to claim 4, wherein the first photovoltaic cell (110) includes multiple groups of photovoltaic cell slices, and the plurality of sub-input ports (220-1, 220-2, 220-3) are adapted to be respectively coupled to the multiple groups of photovoltaic cell slices, and wherein the controller (270) is configured to control the DC-AC conversion circuit (260) to track the maximum power point of the second photovoltaic cell (120), and control the corresponding DC-DC converter in the plurality of DC-DC converters (250-1, 250-2, 250-3) to track the maximum power point of a group of photovoltaic cell slices corresponding to the corresponding DC-DC converter.

6. The inverter device (200) according to claim 1, wherein the DC-AC conversion circuit (260) includes an LLC-based inverter.

7. The inverter device (200) according to claim 2, wherein the DC-DC converter (261) in the DC-AC conversion circuit (260) includes a flyback DC boost converter, and the DC-AC converter (262) in the DC-AC conversion circuit (260) includes a full-bridge inverter.

8. The inverter device (200) according to claim 1 or 2, wherein the first photovoltaic cell (110) includes a crystalline silicon cell, the second photovoltaic cell (120) includes a perovskite cell, and the DC-DC conversion circuit (250) includes a DC boost converter.

9. The inverter device (200) according to claim 1 or 2, wherein the first photovoltaic cell (110) includes a perovskite cell, the second photovoltaic cell (120) includes a crystalline silicon cell, and the DC-DC conversion circuit (250) includes a DC buck converter.

10. A photovoltaic system (10), comprising: a photovoltaic module (100), comprising: a first photovoltaic cell (110); a second photovoltaic cell (120), assembled together with the first photovoltaic cell (110); and an inverter device (200) according to any one of claims 1 to 9, coupled to the photovoltaic module (100).

11. The photovoltaic system (10) according to claim 10, wherein the first photovoltaic cell (110) includes a crystalline silicon cell located at the bottom of the photovoltaic module, and the second photovoltaic cell (120) includes a perovskite cell located at the top of the photovoltaic module, or The first photovoltaic cell (110) includes a perovskite cell located at the top of the photovoltaic module, and the second photovoltaic cell (120) includes a crystalline silicon cell located at the bottom of the photovoltaic module.

12. The photovoltaic system (10) according to claim 11, wherein the first photovoltaic cell (110) and the second photovoltaic cell (120) are assembled together in a stacked manner.

13. A method for controlling an inverter device (200), comprising: Obtaining (1001) first sensing information indicating the output voltage and current of a first photovoltaic cell (110), the first photovoltaic cell (110) being coupled to an AC grid or device (20) via a first input port (220), a DC-DC conversion circuit (250), a DC-AC conversion circuit (260), and an output port (240) of the inverter device (200); Determining (1002) the maximum power point of the first photovoltaic cell (110) based on using the optimal operating voltage of a second photovoltaic cell (120) as the desired output voltage of the DC-DC conversion circuit (250), and based on the first sensing information, the optimal operating voltage representing the voltage output by the second photovoltaic cell (120) associated with the maximum power point of the second photovoltaic cell (120), the second photovoltaic cell (120) being coupled to the AC grid or device (20) via a second input port (230), the output side of the DC-DC conversion circuit (250), the DC-AC conversion circuit (260), and the output port (240); And Generating (1003) a first control signal for the DC-DC conversion circuit (250) based on the optimal operating voltage of the second photovoltaic cell (120) and the determined maximum power point of the first photovoltaic cell (110).

14. The method according to claim 13, further comprising: Obtaining (1101) second sensing information indicating the input voltage and current of the DC-AC conversion circuit (260); Determining (1102) the maximum power point and the optimal operating voltage of the second photovoltaic cell (120) based on the second sensing information; and Generating (1103) a second control signal for the DC-AC conversion circuit (260) based on the determined maximum power point of the second photovoltaic cell (120).

15. The method according to claim 14, wherein the time interval for generating the first control signal is less than the time interval for generating the second control signal.

16. The method according to any one of claims 13 to 15, wherein obtaining (1001) the first sensing information indicating the output voltage and current of the first photovoltaic cell (110) includes: Obtaining a plurality of sub-sensing information respectively indicating the output voltage and current of multiple groups of photovoltaic cells in the first photovoltaic cell (110), wherein determining (1002) the maximum power point of the first photovoltaic cell (110) includes: For each of the plurality of DC-DC converters (250-1, 250-2, 250-3), determine a desired output voltage corresponding to the respective DC-DC converter based on the optimal operating voltage; and determine the maximum power point of the respective set of photovoltaic cells based on the respective sub-sensing information and the respective desired output voltage, and where generating (1003) a first control signal for the DC-DC conversion circuit (250) includes: For each of the plurality of DC-DC converters (250-1, 250-2, 250-3), generate a control signal for the respective DC-DC converter based on the respective desired output voltage and the maximum power point of the respective set of photovoltaic cells corresponding to the respective DC-DC converter.

17. A control device (1200) for an inverter device (200), comprising: a processor (1210); and a memory (1220) coupled to the processor (1210), the memory (1220) having instructions stored therein that, when executed by the processor (1210), cause the controller (1200) to perform the method according to any one of claims 13 to 16.

18. A computer-readable storage medium having computer program code stored thereon, the computer program code, when run, performing the method according to any one of claims 13 to 16.

19. A computer program product tangibly stored on a non-transitory computer-readable medium and including machine-executable instructions that, when executed, cause a machine to perform the steps of the method according to any one of claims 13 to 16.

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