Inverter device and control method thereof, photovoltaic power generation system, control device, computer-readable storage medium, and computer program

Abstract

The embodiments of the present disclosure provide an inverter device, a control method thereof, and a solar power generation system. The inverter device includes a case, a first input port suitable for coupling to a first solar cell, a second input port suitable for coupling to a second solar cell different from the first solar cell, an output port suitable for coupling to an AC power grid or a device, a DC-DC conversion circuit located within the case, the DC-DC conversion circuit having an input side coupled to the first input port and an output side coupled to the second input port, a DC-AC conversion circuit located within the case, the DC-AC conversion circuit having an input side coupled to the second input port and an output side coupled to the output port, and a controller coupled to the DC-DC conversion circuit and the DC-AC conversion circuit and controlling the DC-DC conversion circuit and the DC-AC conversion circuit. The embodiments of the present disclosure enable efficient connection of two solar cells with different voltage levels to an AC power grid or a device.

Description

[Technical Field]

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

[0002] Photovoltaic power generation utilizes the photovoltaic effect of solar cells to convert solar energy or light energy into electrical energy, and has many advantages such as clean, environmentally friendly, and renewable. In order to ensure that the electrical energy generated by the solar cells meets the requirements of the power grid or loads and to improve the power generation efficiency of the solar cells, it is generally necessary to install a power conversion device, such as an inverter device, to convert the voltage or current generated by the solar cells into the required voltage and current.

[0003] In photovoltaic technology, inverter devices can centrally convert the output of a relatively large number of photovoltaic assemblies and provide the power to a power grid or a load, or can convert the output of a single or very few photovoltaic assemblies and provide the power to a power grid or a load. The latter is also called a microinverter device or an assembly-level inverter device. Currently, with the continuous development of photovoltaic technology, several new types of photovoltaic assemblies have appeared one after another, but there is a shortage of inverter devices, especially microinverters, for connecting these photovoltaic assemblies to a power grid or a load. Summary of the Invention [Problem to be solved by the invention]

[0004] To at least partially solve the above and other problems that may exist, embodiments of the present disclosure provide an inverter device, a solar power generation system, a method and control device for controlling the inverter device, a computer-readable storage medium, and a computer program product. [Means for solving the problem]

[0005] According to a first aspect of the present disclosure, there is provided an inverter device including: a case; a first input port suitable for coupling to a first solar cell; a second input port suitable for coupling to a second solar cell different from the first solar cell; an output port suitable for coupling to an AC power grid or an appliance; a DC-DC conversion circuit located within the case, the DC-DC conversion circuit having an input side coupled to the first input port and an output side coupled to the second input port; a DC-AC conversion circuit located within the case, the DC-AC conversion circuit having an input side coupled to the second input port and an output side coupled to the output port; 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-to-AC conversion circuit to track the maximum power point of the second solar cell, set the optimal operating voltage associated with the maximum power point of the second solar cell as the desired output voltage, and control the DC-to-DC conversion circuit to track the maximum power point of the first solar 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 the controller is configured to control the DC-DC converter in the DC-AC conversion circuit to track a maximum power point of the second solar cell, set an optimal operating voltage associated with the maximum power point of the second solar cell as the desired output voltage, and control the DC-DC conversion circuit to track the maximum power point of the first solar cell.

[0008] In some embodiments of the present disclosure, the first input port includes a plurality of sub-input ports, and the DC-DC conversion circuit includes a plurality of DC-DC converters, each coupled to the plurality of sub-input ports at its input side, and connected in series with each other, in parallel with each other, or in series and parallel with each other at its output side.

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

[0010] In some embodiments of the present disclosure, the DC-to-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 solar cell includes a crystalline silicon cell, the second solar cell includes a perovskite cell, and the DC-DC conversion circuit includes a DC boost converter.

[0013] In some embodiments of the present disclosure, the first solar cell includes a perovskite cell, the second solar cell includes a crystalline silicon cell, and the DC-DC conversion circuit includes a DC step-down converter.

[0014] According to a second aspect of the present disclosure, there is provided a solar power generation system, the solar power generation system including a solar power generation assembly including a first solar cell and a second solar cell assembled together with the first solar cell, and an inverter device according to the first aspect coupled to the solar power generation assembly.

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

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

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

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

[0020] In some embodiments of the present disclosure, obtaining first sensing information indicating an output voltage and a current of the first solar cell includes obtaining a plurality of sub-sensing information indicating output voltages and currents of a plurality of sets of solar cells in the first solar cell, respectively. Determining a maximum power point of the first solar cell includes, for each DC-DC converter among the plurality of DC-DC converters, determining a desired output voltage corresponding to the corresponding DC-DC converter based on an optimal operating voltage, and determining a maximum power point of the corresponding set of solar cells based on the sub-sensing information and the desired output voltage. Generating a first control signal for use in the DC-DC conversion circuit includes, for each DC-DC converter among the plurality of DC-DC converters, generating a control signal for use in the corresponding DC-DC converter based on the maximum power point of the set of solar cells corresponding to the corresponding DC-DC converter and the desired output voltage.

[0021] According to a fourth aspect of the present disclosure, there is provided a control device for use in an inverter apparatus, the control device including a processor and a memory coupled to the processor, the memory having instructions stored therein that, when executed by the processor, cause the controller to perform a method according to the third aspect.

[0022] According to a fifth aspect of the present disclosure, there is provided a computer readable storage medium having computer program code stored thereon, the computer program code being adapted to perform the method according to the third aspect when run.

[0023] According to a sixth aspect of the present disclosure, there is provided a computer program product, the computer program product tangibly stored on a non-volatile computer readable medium and including machine executable instructions that, 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 in the specific embodiments below. It is not intended to identify key or primary features of the disclosure, nor is it intended to limit the scope of the disclosure. [Brief explanation of the drawings]

[0025] These and other objects, features, and advantages of the present disclosure will become more apparent from a more detailed description of exemplary embodiments of the present disclosure taken in conjunction with the drawings, in which like reference numerals generally represent like elements in the exemplary embodiments of the present disclosure. [Figure 1] 1 shows a schematic circuit diagram of a solar power generation system and an AC power grid or device according to an embodiment of the present disclosure. [Figure 2] 1 shows an outside view of an inverter device according to an embodiment of the present disclosure. [Figure 3] 1 shows a schematic circuit diagram of a solar power generation system according to an embodiment of the present disclosure. [Figure 4] 1 shows a schematic circuit diagram of a solar power generation system according to an embodiment of the present disclosure. [Figure 5A] 1 shows a schematic circuit diagram of a DC-DC conversion circuit in an inverter device according to an embodiment of the present disclosure. [Figure 5B] 1 shows a schematic circuit diagram of a DC-DC conversion circuit in an inverter device according to an embodiment of the present disclosure. [Figure 6A]1 shows a schematic circuit diagram of a two-stage circuit of a DC-AC conversion circuit in an inverter device according to an embodiment of the present disclosure. [Figure 6B] 1 shows a schematic circuit diagram of a two-stage circuit of a DC-AC conversion circuit in an inverter device according to an embodiment of the present disclosure. [Figure 7] 1 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. [Figure 8] 1 shows a schematic circuit diagram of a solar power generation system according to an embodiment of the present disclosure. [Figure 9A] 1 shows a schematic circuit diagram of a first input port and a DC-DC conversion circuit of an inverter device according to an embodiment of the present disclosure. [Figure 9B] 1 shows a schematic circuit diagram of a first input port and a DC-DC conversion circuit of an inverter device according to an embodiment of the present disclosure. [Figure 10] 1 shows a schematic flowchart of a method for controlling an inverter device according to an embodiment of the present disclosure. [Figure 11] 1 shows a schematic flow chart of a process of a control inverter device according to an embodiment of the present disclosure. [Figure 12] 1 shows a schematic diagram of a control device for controlling an inverter device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, embodiments of the present disclosure will be described in more detail with reference to the drawings. Although the drawings illustrate embodiments of the present disclosure, it should be understood that the present disclosure is not limited to the embodiments described herein, and that various modifications and variations of the present disclosure are possible. On the contrary, these embodiments are provided to make the present disclosure more detailed and complete, and to fully convey the scope of the present disclosure to those skilled in the art. Those skilled in the art may derive alternative technical solutions from the following description without departing from the spirit and scope of the present disclosure.

[0027] As used herein, the term "comprises" and variations thereof refer to an open inclusive, i.e., "including, but not limited to." Unless otherwise specified, the term "or" refers to "and / or." The term "based on" refers to "based at least in part on." The terms "in one example" or "in one embodiment" refer to "at least one embodiment." The following may include other explicit and implicit definitions.

[0028] An embodiment of the present disclosure provides an improved photovoltaic inverter solution. In this solution, at least two power conversion stages are installed within the inverter device housing, and one of the two power conversion stages is installed between two input ports. Thus, the inverter device receives output power from a first solar cell and a second solar cell, which have different voltage levels, and after power conversion, directly provides the output power to a downstream AC power grid or AC device. Furthermore, this solution achieves maximum power point tracking for both the first solar cell and the second solar cell, ensuring that both solar cells operate at the highest power generation efficiency. In some new photovoltaic assemblies, two different types of solar cells with a relatively large output voltage difference are assembled into a single photovoltaic assembly, which presents a problem of grid connection difficulties. In particular, there is a lack of microinverter solutions that directly connect such a single photovoltaic assembly to an AC power grid or AC device. The solution disclosed herein connects a photovoltaic assembly having two different types of solar cells to the grid or directly to an AC load via one inverter device, and achieves independent power conversion and control for each photovoltaic assembly and each different type of battery in each photovoltaic assembly, thereby providing greater flexibility and reliability, saving power consumption, reducing costs, and maximizing system efficiency.

[0029] FIG. 1 illustrates a schematic circuit diagram of a solar power generation system 10 and an AC power grid or device 20 according to an embodiment of the present disclosure. As illustrated in FIG. 1, the solar power generation system 10 and the AC power grid or device 20 are coupled to each other, and the solar power generation system 10 supplies electrical energy generated by solar power generation to the AC power grid or device 20. For example, the AC power grid or device 20 may be an AC distribution grid having a live line L and a neutral line N. In another example, the AC power grid or device 20 may be an AC bus that aggregates and transports electrical energy output from multiple solar power generation systems or multiple solar power generation assemblies to the outside. In a further example, the AC power grid or device 20 may be an AC load that receives and consumes the AC electrical energy generated by the solar power generation system 10. As can be appreciated, the AC power grid or device 20 may be an AC power network, AC device, or AC load at a different level or type, and the present disclosure is not limited thereto.

[0030] The solar power system 10 includes a solar power assembly 100. The solar power assembly 100 includes a first solar cell 110 and a second solar cell 120. The first solar cell 110 and the second solar cell 120 may be assembled together, for example, by fasteners or other assembly means, thereby forming a single solar cell 110 and a second solar cell 120. As can be appreciated, the solar power assembly 100 may further include other components or elements necessary to form the assembly, such as packaging materials, a support frame, etc. In one embodiment, the first solar cell 110 is located at the bottom of the solar power assembly, and the second solar cell 120 is located at the top of the solar power assembly, the second solar cell 120 having a wider bandgap than the first solar cell 110, the first solar cell 110 may include a crystalline silicon cell, and the second solar cell 120 may include a perovskite cell. Crystalline silicon cells are manufactured using crystalline silicon materials and have advantages such as high conversion efficiency, strong stability, and mature processes. Perovskite cells, on the other hand, use perovskite structural materials as light-absorbing materials and have features such as low cost, high light absorption coefficient, long carrier diffusion length, tunable band gap (e.g., 1.17-2.8 eV), and high theoretical conversion efficiency. In one embodiment, the first solar cell 110 includes one or more crystalline silicon cells, and the second solar cell 120 includes one or more perovskite cells. Generally speaking, the output voltage of the first solar cell 110 is lower than 40 V or 50 V, but the output voltage of the second solar cell 120 is much higher than that of the first solar cell 110 and can reach 200 V. In one embodiment, the first solar cell 110 and the second solar cell 120 are assembled in a vertically stacked manner, and the two are optically coupled and electrically isolated from each other.For example, if the first solar cell 110 is a crystalline silicon cell and the second solar cell 120 is a perovskite cell, the band gap of the perovskite cell can be adjusted to an appropriate width to enhance the absorption and utilization efficiency of short-wavelength light (which generally mainly absorbs high-energy photons with a wavelength of less than 800 nm) and have a greater transmittance. Therefore, the second solar cell 120 (which particularly absorbs low-energy photons with a wavelength of less than 1100 nm) can be stacked above the first solar cell 110. For example, by stacking a sheet-shaped perovskite cell and a sheet-shaped crystalline silicon cell in a stacking manner, the two types of solar cells can be placed in the same photovoltaic assembly. By combining cells with different band gaps, the solar spectrum can be divided and utilized, and more efficient light absorption and conversion can be achieved. This effectively improves power conversion efficiency, reduces energy loss, and does not occupy additional land area. In one example, the solar power generation assembly 100 in the solar power generation system 10 may be placed alone in a relatively small area, such as a balcony, or may be placed together with other solar power generation assemblies 100 in a relatively large area, such as a roof, and the present disclosure does not limit the application location of the solar power generation system 10.

[0031] The solar power generation system 10 further includes an inverter device 200, which is coupled between the solar power generation assembly 100 and an AC power grid or an apparatus 20. For example, the inverter device 200 may be a micro-inverter device that couples a single solar power generation assembly 100 to an AC power grid or an apparatus 20, and may be attached to the back of the frame of the solar power generation assembly 100 or attached near the solar power generation assembly 100. The inverter device 200 can receive power from both the first solar cell 110 and the second solar cell 120 of the solar power generation assembly 100, convert it into AC power, and output it to the AC power grid or the apparatus 20.

[0032] FIG. 2 illustrates an exterior view of an inverter device 200 according to an embodiment of the present disclosure. As illustrated in FIG. 2 , the inverter device 200 includes a case 210, a first input port 220 suitable for coupling to a first solar cell 110, and a second input port 230 suitable for coupling to a second solar cell 210. The inverter device 200 further includes an output port 240 suitable for coupling to an AC power grid or a 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. The first input port 220, the second input port 230, and the output port 240 allow a circuit within the case 210 to be electrically coupled or connected to the solar power assembly 100 and the AC power grid or the device 20, thereby transmitting power generated by the solar power assembly 100 to the AC power grid or the device 20. As can be understood, the inverter device 200 may include other suitable members on the case 210 or outside the case 210, such as a heat dissipation member and a mounting member for fixing the inverter device 200.

[0033] FIG. 3 shows a schematic circuit diagram of a solar power generation system 10 according to an embodiment of the present disclosure. Compared to FIGS. 1 and 2, FIG. 3 shows the internal circuit of the inverter device 200 in more detail. As shown in FIG. 3, the inverter device 200 includes a DC-DC conversion circuit 250 located within a case 210. The DC-DC conversion circuit 250 is coupled at its input side to a first input port 220 and at its output side to a second input port 230. Specifically, the first input port 220 and the second input port 230, which are coupled to different solar cells, input two different DC voltages into the inverter device 210. The DC-DC conversion circuit 250 coupled between the two input ports can convert the voltage so that one of the two input voltages is the same as or similar to the other input voltage. This eliminates the voltage difference between the two input voltages and allows the two input paths to be combined into one path for output to a subsequent circuit. In one embodiment, the DC-DC conversion circuit 250 includes a DC boost (BOOST) converter. For example, if the first solar cell 110 is a crystalline silicon cell and is coupled to the first input port 220, and the second solar cell 120 is a perovskite cell and is coupled to the second input port 230, the first solar cell 110 outputs a relatively low voltage (e.g., about 40 V or 50 V) to the first input port 220, while the second solar cell 120 outputs a higher voltage (e.g., about 200 V) to the second input port 230. The DC-DC conversion circuit 250 functions as a boost converter, boosting the relatively low voltage input by the crystalline silicon cell via the first input port 220 to approximately the relatively high voltage output from the second solar cell 120. In another embodiment, the DC-DC conversion circuit 250 includes a DC buck (BUCK) converter.For example, if the first solar cell 110 is a crystalline silicon cell and is coupled to the second input port 230, and the second solar cell 120 is a perovskite cell and is coupled to the first input port 220 (i.e., the connections of the two solar cells and the two input ports in FIG. 3 are swapped), the first solar cell 110 outputs a relatively low voltage (e.g., about 40 V or 50 V) to the second input port 230, while the second solar cell 120 outputs a high voltage (e.g., about 200 V) to the first input port 220. The DC-DC conversion circuit 250, as a buck converter, can step down the relatively high voltage input from the perovskite cell via the first input port 220 to approximately the output voltage of the first solar cell 110. The DC-DC conversion circuit 250 employs a step-down circuit in a scenario where the output power of the low-voltage solar cell is relatively high but the output power of the high-voltage solar cell is relatively low. However, compared with the solution using a step-down circuit, the solution using a step-up circuit in the DC-DC conversion circuit 250 is more advantageous because the step-up circuit allows the high-voltage input to directly enter the subsequent stage and gradually increases the low-voltage input to a high voltage, thereby improving the operating voltage of the subsequent stage circuit and reducing the operating current, which helps to minimize the power consumption of the solar power generation system and its inverter device.

[0034] According to an embodiment of the present disclosure, the inverter device 200 includes a DC-AC conversion circuit 260. The DC-AC conversion circuit 260 is located within the case 210, and has an input side coupled to the second input port 230 and an output side coupled to the output port 240. Specifically, the DC-AC conversion circuit 260 can appropriately convert the solar-generated DC power from the second input port 230 and the solar-generated DC power converted by the DC-DC conversion circuit 250 from the first input port 220, to generate AC power required by the AC power grid or the device 20.

[0035] 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. For example, the controller 270 may be implemented in the form of a controller having calculation and processing capabilities, such as a microcontroller unit (MCU) or a digital signal processor (DSP). The controller 270 may be implemented in the form of an analog circuit and / or a digital circuit, or a combination of the above various forms. The controller 270 can acquire sensing information related to electrical quantities (e.g., voltage, current, etc.) of the DC-DC conversion circuit 250, the DC-AC conversion circuit 260, the first solar cell 110, and the second solar cell 120 from the sensing devices, and control the power switching devices in the DC-DC conversion circuit 250 and the DC-AC conversion 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 conversion circuit 250 and the DC-AC conversion circuit 260 to perform necessary power conversion operations. In some embodiments, the controller 270 can set an optimal operating voltage associated with the maximum power point of the second solar cell 120 as the desired output voltage, control the DC-AC conversion circuit 260 to track the maximum power point of the second solar cell 120, and control the DC-DC conversion circuit 250 to track the maximum power point of the first solar cell 110. As an example, the controller 270 can perform maximum power point tracking (MPPT) for the first solar cell 110 and the second solar cell 120 using the DC-DC conversion circuit 250 and the DC-AC conversion circuit 260.The controller 270 can use an MPPT algorithm based on the sensing information to determine the maximum power points of the first solar cell 110 and the second solar cell 120 in their current states, and can adjust the output voltage and current of the first solar cell 110 and the second solar cell 120 by controlling the DC-DC conversion circuit 250 and the DC-AC conversion circuit 260, respectively. Here, before performing maximum power point tracking for the first solar cell 110, the controller 270 can first determine the maximum power point of the second solar cell 120 and determine the optimal operating voltage of the second solar cell 120. This optimal operating voltage can then be used as the desired output voltage of the DC-DC conversion circuit 250, and the controller 270 can track the maximum power point of the first solar cell 110 based on this, so that both the first solar cell 110 and the second solar cell 120 can operate at their maximum power points and output maximum power in their current states. This method not only enables the simultaneous reception of output power from two solar cells with a relatively large voltage difference in a single solar power assembly, but also ensures that both solar cells operate at maximum output power when environmental factors such as ambient temperature and light intensity change, which effectively improves the power generation efficiency of the solar power system and its solar power assembly, reduces the cost of solar power generation, and also helps reduce losses in the solar power assembly and extend its service life.

[0036] As can be understood, in addition to the circuits and components shown in FIG. 3 , the inverter device 200 may include other circuits or components as needed, such as an electromagnetic interference (EMI) filter 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.

[0037] FIG. 4 shows a schematic circuit diagram of a solar power generation system 10 according to another embodiment of the present disclosure. Different from FIG. 3 , FIG. 4 further illustrates an implementation of a DC-AC conversion circuit 260. As shown in FIG. 4 , 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, where the first stage circuit is used to further boost the DC voltage to ensure that the voltage reaches a sufficiently high voltage level, and the second stage circuit is used to convert the DC power to AC power to ensure that the power output from the inverter device 200 is suitable for transmission to the AC power grid or the device 20. In one embodiment, the controller 270 can control the DC-DC converter 261 in the DC-AC conversion circuit 260 to track the maximum power point of the second solar cell 120. Specifically, in the two-stage DC-AC conversion circuit 260, the controller 270 may control only the front-stage DC-DC converter 261 to achieve MPPT operation for the second solar cell 120. Alternatively, the DC-AC conversion circuit 260 may be a single-stage circuit, and the single-stage circuit achieves boost inverter operation and / or 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 solar power generation assembly 100 from the high-voltage AC power grid or the equipment 20, thereby ensuring the safety of equipment and personnel.

[0038] 5A and 5B show schematic circuit diagrams of a DC-DC conversion circuit 250 in an inverter apparatus 200 according to an embodiment of the present disclosure. As shown in FIG. 5A, the DC-DC conversion circuit 250 may be a BOOST converter and includes an inductor L1, power switching devices Q1 and Q2, and capacitors C1 and C2. When the voltage of the second input port 230 is higher than the voltage of the first input port 220, the BOOST converter boosts the voltage of the first input port 220 and performs maximum power point tracking for the solar cell coupled to the first input port 220. For example, the first input port 220 may be coupled to one side of the capacitor C1 of the BOOST converter, and one side of the capacitor C2 may be coupled to the second input port 230 and the input side of the DC-AC conversion circuit 260. The controller 270 may realize boost and MPPT operations by turning on and off the power switching device Q1 (e.g., in a PWM control mode). As shown in FIG. 5B, the DC-DC conversion circuit 250 may be a BUCK converter, which has the same components and topology as the BOOST converter of FIG. 5A (the difference from FIG. 5A is that the input and output sides are swapped). 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 for the solar cell connected to the first input port 220. For example, the first input port 220 may be coupled to one side of the capacitor C2 of the BUCK converter, and one side of the capacitor C1 may be coupled to the second input port 230 and the input side of the DC-AC conversion circuit 260. The controller 270 may perform on / off control of the power switching device Q2 (e.g., PWM control mode) to achieve step-down and MPPT operation. It should be understood that the above implementation of the DC-DC conversion circuit 250 is merely exemplary, and other components and elements may be added, removed, or replaced as needed. It should be noted that in addition to the BOOST and BUCK circuits, the DC-DC converter circuit 250 may employ other types of DC step-up or step-down circuits already developed or developed in the future.

[0039] 6A and 6B show schematic circuit diagrams of two-stage circuits 261 and 262 of a DC-AC conversion circuit 260 in an inverter device 200 according to an embodiment of the present disclosure. As shown in FIG. 6A, the DC-DC converter 261 may be a flyback DC boost converter. For example, the flyback DC boost converter includes a power switching device 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 for a solar 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 the capacitor C3 of the flyback boost converter, and one side of the capacitor C4 is coupled to the downstream DC-AC converter 262. The controller 270 receives sensing information (e.g., the source current of the power switching device Q3, the output current of the flyback converter, and sensed electrical quantities related to MPPT operation) and controls the power switching device Q3 to turn on and off (e.g., in PWM control mode) to achieve boost and MPPT operation. Note that the DC-DC converter 261 as a flyback DC boost converter can also employ active clamping and / or voltage doubler rectification techniques to improve the converter's conversion efficiency and reduce the voltage stress of the power switching device. As shown in FIG. 6B , the DC-AC converter 262 can be a full-bridge inverter. For example, the full-bridge inverter includes power switching devices 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 (e.g., the inverter current output from the full-bridge arm) and realize inverter operation by performing on and off operations (e.g., PWM control mode) on the power switching devices Q4, Q5, Q6 and Q7.

[0040] 7 shows a schematic circuit diagram of a single-stage circuit of the DC-AC conversion circuit 260 in the inverter apparatus 200 according to an embodiment of the present disclosure. As shown in FIG. 7, the DC-AC conversion circuit 260 includes an LLC-based inverter. For example, the LLC-based inverter may be an LLC-based cycloconverter, which includes power switching devices Q8-Q15, an isolation transformer T2, an inductor L3, and capacitors C7-C10. The LLC-based inverter boosts the input voltage, inverts the DC power, and performs maximum power point tracking for the solar 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. The controller 270 receives sensing information (such as the inverter current output from the isolation transformer T2 and sensing electrical quantities related to MPPT operation) and performs on and off operations (such as PWM control mode) on the power switching devices Q8 to Q15 to realize boost, inverter and MPPT operations.

[0041] It should be 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. In addition to the flyback converter, full-bridge inverter, and LLC-based inverter circuit, the DC-AC conversion circuit 260 may also employ other types of DC-AC conversion circuits that have been developed or will be developed in the future.

[0042] FIG. 8 shows a schematic circuit diagram of a solar power generation system 10 according to a further embodiment of the present disclosure. The difference from FIG. 3 is that the first input port 220 in FIG. 8 includes multiple sub-input ports, e.g., sub-input ports 220-1, 220-2, and 220-3, and the DC-DC conversion circuit 250 includes multiple DC-DC converters, e.g., DC-DC converters 250-1, 250-2, and 250-3. The 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, respectively, on their input sides and connected in series to each other on their output sides. The first solar cell 110 includes multiple sets of solar cell cells, and the multiple sub-input ports 220-1, 220-2, and 220-3 are coupled to the multiple sets of solar cell cells, respectively.

[0043] For example, if the first solar cell 110 is a solar cell such as a crystalline silicon cell, the first solar cell 110 may include multiple solar cells, which may be divided into multiple groups, each group including at least one battery cell. In a conventional solution, a distribution box may be provided in the solar power assembly to distribute DC power generated by the solar power assembly to a downstream circuit, such as an inverter. The distribution box typically includes bypass diodes connected in parallel to each group of battery cells, which can bypass the corresponding group of battery cells in the solar power assembly in certain cases. For example, if a group of battery cells is shielded or partially damaged, the bypass diodes connected in parallel to the group of battery cells can bypass the group of battery cells to prevent the group of battery cells from being damaged by a hot spot effect, thereby ensuring that the other battery cells can still operate normally. However, even if a group of cells is partially shielded or partially damaged by such a bypass diode, the entire group of cells will no longer output power. Furthermore, because the distribution box and its bypass diode are relatively prone to damage and failure in a solar power generation system, they must be constantly repaired and replaced throughout the useful life of the solar power generation system and its solar power generation assembly. By providing multiple sub-input ports and multiple DC-DC converters in the inverter device 200, the power generated by each group of solar cells among multiple groups of solar cells can be directly adjusted and output. For example, when a group of solar cells is shielded, the corresponding DC-DC converter can adjust the voltage of the output of that group of solar cells and output it externally without bypassing it. This eliminates the need for conventional bypass diodes and distribution boxes in solar power generation assemblies.This method not only eliminates the need for a power distribution box and its bypass diodes, which have a relatively high failure rate, thereby increasing system reliability, but also improves energy utilization efficiency by ensuring that shielded or partially damaged battery cell groups can still output a certain amount of power.

[0044] In some embodiments, the controller 270 can control each DC-DC converter in the plurality of DC-DC converters 250-1, 250-2, and 250-3 to track the maximum power point of the corresponding set of solar cells. For example, the controller 270 can control the DC-DC converter 250-1 based on the maximum power point of the set of solar cells coupled to the sub-input port 220-1 so that the DC-DC converter 250-1 adjusts the output voltage and current of the set of solar cells to the maximum power point. This approach allows independent MPPT control for each set of solar cells in the first solar cell 110, thereby achieving greater flexibility and higher power generation efficiency.

[0045] In another embodiment, the multiple DC-DC converters 250-1, 250-2, and 250-3 may be connected to the output port 230 in a parallel connection manner at their output sides, or in a mixed series and parallel connection manner at their output sides (for example, some converters are connected in series at their output sides and then connected in parallel with the remaining converters at their output sides, or some converters are connected in parallel at their output sides and then connected in series with the remaining converters at their output sides) at their output sides. However, compared with the parallel and series-parallel connection manners, adopting a series connection manner to combine multiple DC-DC converters is more advantageous because the series connection manner can ensure that each DC-DC converter does not need to increase the voltage to an excessively high level, so that the working duty cycle of each DC-DC converter is relatively moderate and a relatively high output voltage can be more easily obtained, thereby improving the overall efficiency.

[0046] 9A and 9B show schematic circuit diagrams of the first input port 220 of the inverter device 200 and the DC-DC conversion circuit 250 according to an embodiment of the present disclosure. As shown in Fig. 9A, the DC-DC converters 250-1 to 250-3 of the DC-DC conversion circuit 250 are BOOST conversion circuits, and are connected in series to each other at the output sides thereof to output power. For example, DC-DC converter 250-1 includes inductor L4-1, power switching devices Q16-1 and Q17-1, and capacitors C11-1 and C12-1, and is coupled to one side of capacitor C11-1 to sub-input port 220-1; DC-DC converter 250-2 includes inductor L4-2, power switching devices Q16-2 and Q17-2, and capacitors C11-2 and C12-2, and is coupled to one side of capacitor C11-2 to sub-input port 220-2; and DC-DC converter 250-3 includes inductor L4-3, power switching devices Q16-3 and Q17-3, and capacitors C11-3 and C12-3, and is coupled to one side of capacitor C11-3 to sub-input port 220-3. The controller 270 controls the power switching devices Q17-1, Q17-2, and Q17-3 (e.g., in PWM control mode) to perform boost and MPPT operations on the battery cell groups connected to the sub-input ports 220-1, 220-2, and 220-3, respectively. The difference from Fig. 9A is that the multiple DC-DC converters 250-1 to 250-3 in Fig. 9B are connected in parallel to each other at their output sides before outputting power. The elements or components and other connection methods in Fig. 9B are similar to those in Fig. 9A, and will not be further described.

[0047] Since the number of bypass diodes in a conventional distribution box is generally three, the number of sub-input ports 220-1, 220-2, and 220-3 and the number of DC-DC converters 250-1, 250-2, and 250-3 shown in Figures 8, 9A, and 9B is also three. However, the number of sub-input ports and corresponding DC-DC converters in inverter device 200 may be more or less depending on the actual situation.

[0048] 10 shows a schematic flow chart of a method 1000 for controlling the inverter device 200 according to an embodiment of the present disclosure. The method 1000 may be implemented in the scenarios in FIGS. 1, 3, 4, and 8 and executed by the controller 270. For purposes of discussion, the method 1000 will be described with reference to FIGS. 1 through 9.

[0049] In box 1001, the controller 270 obtains first sensing information indicating the output voltage and current of the first solar cell 110, which is coupled to the AC power grid or the device 20 via the first input port 220, the DC-DC conversion circuit 250, the DC-AC conversion circuit 260, and the output port 240 of the inverter device 200. For example, a sensing device for sensing the voltage and current generated and output by the first solar cell 110 may be installed on the connection wiring between the first solar cell 110 and the DC-DC conversion circuit 150, for example, near the first input port 220. By receiving the sensing information from the sensing device, the controller 270 can know the current output power status of the first solar cell 110 and easily determine the maximum power point in the current state of the first solar cell 110.

[0050] In some embodiments of the present disclosure, the controller 270 acquires multiple pieces of sub-sensing information indicating the output voltages and currents of the multiple sets of solar cells in the first solar cell 110. For example, in the solar power generation system 10 shown in FIG. 8 , sensing devices for sensing the voltages and currents generated and output by each set of battery cells may be installed on the current path between each set of battery cells in the first solar cell 110 and the corresponding DC-DC converter, for example, near the sub-input ports 220-1, 220-2, and 220-3. By receiving the multiple pieces of sub-sensing information from these sensing devices, the controller 270 can determine the current output power status of each set of battery cells in the first solar cell 110. The sub-sensing information helps determine the maximum power point in the current state of each set of battery cells in the first solar cell 110.

[0051] In box 1002, based on setting the optimal operating voltage of the second solar cell 110 as the desired output voltage of the DC-DC conversion circuit 250 and based on the first sensing information, the controller 270 determines a maximum power point of the first solar cell 110, where the optimal operating voltage represents a voltage output by the second solar cell 120 associated with the maximum power point of the second solar cell 120, and the second solar cell 120 is coupled to the AC power grid or the device 20 via the second input port 230 of the inverter device 200, the output side of the DC-DC conversion circuit 250, the DC-AC conversion circuit 260, and the output port 240. For example, before applying control to the DC-DC conversion circuit 250, the controller 270 can predetermine or obtain the maximum power point of the second solar cell 120 and determine an optimal operating voltage associated with the maximum power point, i.e., when the second solar cell 120 sets the optimal operating voltage as the battery output voltage, the second solar cell 120 can output maximum power. This optimal operating voltage is then set as the desired output voltage at the output side of the DC-DC conversion circuit 250. For example, the controller 270 can obtain first sensing information indicating the output voltage and current of the first solar cell 110, and determine the desired output voltage at the output side of the DC-DC conversion circuit 250, and then use an MPPT algorithm to determine and track the maximum power point of the first solar cell 110. The MPPT algorithm may include, for example, algorithms such as a perturbation and observation method, an incremental conductance method, and may also include related MPPT algorithms that will be developed in the future. In this manner, the output voltage of the DC-DC conversion circuit 250 is fixed at a certain determined voltage, thereby enabling the determination of the maximum power point of the first solar cell 110 (if the output voltage of the DC-DC conversion circuit 250 is in a changing state, the maximum power point of the first solar cell 110 cannot be determined), and since the second solar cell 120 is directly coupled to the output side of the DC-DC conversion circuit 250 via the second output port 230, it can be ensured that the DC-DC conversion circuit 250 can adjust its output voltage to match the voltage of the maximum power point of the second solar cell 120, thereby helping to realize maximum power point tracking for the second solar cell 120.

[0052] In some embodiments of the present disclosure, for each DC-DC converter among 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 working voltage, and determines a maximum power point of the corresponding set of solar cells based on the corresponding sub-sensing information and the corresponding desired output voltage. For example, in the solar power generation system 10 shown in Figure 8, the plurality of DC-DC converters 250-1, 250-2, and 250-3 are coupled to each other in a series connection manner on the output side, so that the controller 270 can decompose the optimal working voltage into the desired output voltage of each DC-DC converter in an appropriate proportion to ensure that the sum of the plurality of desired output voltages is equal to the optimal working voltage. For example, if the optimal operating voltage is 180V, the total desired output voltage of the multiple DC-DC converters 250-1, 250-2, and 250-3 is 180V, which means that the desired output voltage of each of the three DC-DC converters 250-1, 250-2, and 250-3 can be set to 60V. This allows the controller 270 to determine the desired output voltage at the output side of each DC-DC converter 250-1, 250-2, and 250-3. Furthermore, after determining the desired output voltage of each DC-DC converter and obtaining the voltage and current information of the battery cell groups corresponding to each DC-DC converter, the controller 270 can use an MPPT algorithm to determine the maximum power point of each set of solar cells.

[0053] Alternatively, when multiple DC-DC converters 250-1, 250-2, 250-3 are connected to each other at their output sides in a parallel connection manner or a mixed series-parallel connection manner, the controller 270 can determine the desired output voltage of each DC-DC converter in the DC-DC conversion circuit 250 in a similar manner, where the desired output voltage of each DC-DC converter 250-1, 250-2, 250-3 in a parallel connection manner is the same as the optimal working voltage of the second solar cell 120, but the desired output voltage of each DC-DC converter 250-1, 250-2, 250-3 in a series-parallel connection manner can be determined by decomposing the optimal working voltage according to the actual connection manner, and it is necessary to ensure that the total output voltage of each DC-DC converter at the output side is equal to the optimal working voltage.

[0054] In box 1003, based on the optimum operating voltage of the second solar cell 120 and the determined maximum power point of the first solar cell 110, the controller 270 generates a first control signal to be used for the DC-DC conversion circuit 250.

[0055] For example, the controller 270 may determine a desired input voltage and current for the DC-DC conversion circuit 250 based on the previously determined maximum power point for the first solar cell 110. Because the input voltage and current of the DC-DC conversion circuit 250 are actually the output voltage and current of the first solar cell 110, when the DC-DC conversion circuit 250 adjusts its input voltage and current to the desired input voltage and current associated with the maximum power point of the first solar cell 110, it can ensure that the first solar cell 110 operates at its maximum power point, thereby achieving maximum power point tracking for the first solar cell 110. In addition, the controller 270 may further determine the optimal operating voltage of the second solar cell 120 as the desired output voltage of the DC-DC conversion circuit 250. Thereby, the controller 270 can adjust both the input side and the output side of the DC-DC conversion circuit 250 to desired voltage and current levels by generating a first control signal to control a power switching device (e.g., Q1 or Q2) in the DC-DC conversion circuit 250 to perform an on-off operation. This method not only realizes maximum power point tracking for the first solar cell 110, but also helps realize maximum power point tracking for the second solar cell 120 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 solar cell 120.

[0056] In some embodiments of the present disclosure, for each of the DC-DC converters 250-1, 250-2, and 250-3, the controller 270 generates a control signal for the corresponding DC-DC converter based on the maximum power point of the set of solar cells corresponding to the corresponding DC-DC converter and the corresponding desired output voltage. For example, in the solar power generation system 10 shown in Figure 8, the multiple DC-DC converters 250-1, 250-2, and 250-3 are coupled to each other in a series connection manner on the output side, and the controller 270 appropriately decomposes the optimal operating voltage of the second solar cell 120 into the desired output voltages of each DC-DC converter to ensure that the sum of the multiple desired output voltages is equal to the optimal operating voltage. It should be noted that the controller 270 can determine the desired voltage and current at the input side of each DC-DC converter 250-1, 250-2, 250-3 based on the previously determined maximum power point for each set of battery cells, which is also the desired output voltage and current of each set of solar cell of the first solar cell 110. After determining the desired output voltage and desired input voltage and current of each DC-DC converter, the controller 270 can issue control signals to the power switching devices (e.g., Q17-1, Q17-2, and Q17-3) of each DC-DC converter 250-1, 250-2, 250-3 based on the determined maximum power point for each set of battery cells, to adjust the input side and output side of each DC-DC converter 250-1, 250-2, 250-3 to the desired voltage and / or current levels. For example, the controller 270 can generate control signals for the power switching devices of the DC-DC converter 250-1 based on the desired input voltage and current and the desired output voltage of the DC-DC converter 250-1, thereby achieving maximum power point tracking for each set of solar cells in the first solar cell 110 and helping the second solar cell 120 operate at its maximum power point.

[0057] 11 shows a schematic flowchart 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, where boxes 1101 and 1102 of process 1100 need to be performed before box 1002 in FIG. 10 to facilitate determining the optimal operating voltage required for box 1002, and each box in process 1100 may be performed independently for each box in FIG. 10.

[0058] In box 1101, the controller 270 obtains second sensing information indicating the input voltage and current of the DC-AC conversion circuit 260. For example, a sensing device for sensing the voltage and current may be installed on the input side of the DC-AC conversion circuit 260 or on the connecting wiring nearby the input side of the DC-AC conversion circuit 260. The controller 270 can, for example, obtain the second sensing information from the installed sensing device to facilitate determining the maximum power point of the current state of the second solar cell 120.

[0059] In box 1102, based on the second sensing information, the controller 270 determines the maximum power point and the aforementioned optimal operating voltage of the second solar cell 120. For example, the controller 270 can use an MPPT algorithm based on the second sensing information to calculate and determine the maximum power point in the current state of the second solar cell 120. When the maximum power point is determined, the output voltage at the maximum power point of the second solar cell is also naturally determined and is taken as the optimal operating voltage of the second solar cell 120, which is used to control the DC-DC conversion circuit 250 in box 1003.

[0060] In box 1103, based on the determined maximum power point of the second solar cell 120, the controller 270 generates a second control signal to be used for the DC-AC conversion circuit 260. For example, the controller 270 can control the DC-AC conversion circuit 260, or control the DC-DC converter 261 in the DC-AC conversion circuit 260, to ensure that the voltage at the input side of the DC-AC conversion circuit 260 is maintained at the maximum power point voltage (i.e., the optimal operating voltage), so that the second solar cell 120 can operate at the maximum power point under the current conditions to achieve MPPT.

[0061] In some embodiments of the present disclosure, the time interval at which the controller 270 generates the first control signal is shorter than the time interval at which the controller 270 generates the second control signal. Specifically, the second control signal generated by the controller 270 is used to control the DC-AC conversion circuit 260 to perform maximum power tracking for the second solar cell 120, while the first control signal generated by the controller 270 is used to control the DC-DC conversion circuit 250 to perform maximum power tracking for the first solar cell 120. As discussed above, controlling the DC-DC conversion circuit 250 to complete maximum power point tracking for the first solar cell 110 is based on determining the optimal operating voltage of the second solar cell 120 and controlling the DC-AC conversion circuit 260 to adjust the output voltage of the second solar cell 120. Therefore, maximum power point tracking for the second solar cell 120 may be set to be performed slowly over a long period of time, while maximum power point tracking for the first solar cell 110 may be set to be performed quickly over a short period of time. In one example, the time length of the long cycle may be an integer multiple of the time length of the short cycle. For example, the long cycle may be 1 second, while the short cycle may be 100 milliseconds, i.e., one MPPT operation cycle for the second solar cell 120 may correspond to 10 MPPT operation cycles for the first solar cell 110. This method ensures that the DC-DC conversion current 250 can track the maximum power point of the first solar cell 110 as quickly as possible through multiple MPPT operations within a relatively short period of time, without waiting for the second solar cell 120 to track, thereby improving the efficiency of the entire system.

[0062] FIG. 12 shows a schematic diagram of a control device 1200 for controlling the inverter apparatus 200 according to an embodiment of the present disclosure. The control device 1200 can be implemented as the controller 270 in FIGS. 3, 4, and 8, and can implement the methods and processes in FIGS. 10 and 11. As shown in FIG. 12, the control device 1200 can 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 FIGS. 10 and 11.

[0063] It should be understood by those skilled in the art that the steps of the methods disclosed herein can be implemented by a general-purpose computing device, and may be centralized on a single computing device or distributed over a network of multiple computing devices. Alternatively, they may be implemented by executable program code on the computing device, thereby storing them in a storage device and executing them on the computing device, or may be implemented as individual integrated circuit modules, or multiple modules or steps therein may be implemented by implementing them as a single integrated circuit module. Thus, the present disclosure is not limited to any particular combination of hardware and software.

[0064] It should be understood that although the above detailed description refers to multiple units or sub-units of equipment, such division is exemplary only and is not mandatory. Indeed, according to embodiments of the present disclosure, features and functionality of two or more of the units described above may be embodied in a single unit. Conversely, features and functionality of a single unit described above may be further divided and embodied by multiple units.

[0065] As described above, the present disclosure is merely a selective embodiment and is not intended to limit the present disclosure, and those skilled in the art can make various modifications and variations to the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. A case (210), a first input port (220) suitable for coupling to a first solar cell (110); a second input port (230) suitable for coupling to a second solar cell (120) different from the first solar cell (110); an output port (240) suitable for coupling to an AC power grid or to a device (20); a DC-DC converter circuit (250) located within the case (210), the DC-DC converter circuit (250) having an input side coupled to the first input port (220) and an output side coupled to the second input port (230); a DC-AC converter circuit (260) located within the case (210), the DC-AC converter circuit (260) having an input side coupled to the second input port (230) and an output side coupled to the output port (240); 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. 2. The inverter device (200) of claim 1, wherein the controller (270) is configured to control the DC-AC conversion circuit (260) to track a maximum power point of the second solar cell (120), set an optimal operating voltage associated with the maximum power point of the second solar cell (120) as a desired output voltage, and control the DC-DC conversion circuit (250) to track a maximum power point of the first solar cell (110).

3. The DC-AC conversion circuit (260) includes a DC-DC converter (261) and a DC-AC converter (262) coupled in series, and 2. The inverter device (200) of claim 1, 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 solar cell (120), set an optimal operating voltage associated with the maximum power point of the second solar cell (120) as a desired output voltage, and control the DC-DC conversion circuit (250) to track the maximum power point of the first solar cell (110).

4. The first input port (220) includes a plurality of sub-input ports (220-1, 220-2, 220-3), and 2. The inverter device according to claim 1, wherein the DC-DC conversion circuit includes a plurality of DC-DC converters, each of which is coupled at its input side to the corresponding one of the plurality of sub-input ports and is connected at its output side to one another in series, in parallel, or in both series and parallel.

5. the first solar cell (110) includes a plurality of sets of solar cell units, and the plurality of sub-input ports (220-1, 220-2, 220-3) are suitable for coupling to the plurality of sets of solar cell units, respectively; 5. The inverter device (200) according to claim 4, wherein the controller (270) is configured to control the DC-AC conversion circuit (260) to track a maximum power point of the second solar cell (120), and to control a corresponding DC-DC converter (250-1, 250-2, 250-3) to track a maximum power point of a set of solar cell cells corresponding to the corresponding DC-DC converter in the plurality of DC-DC converters (250-1, 250-2, 250-3).

6. The inverter device (200) of any preceding claim, wherein the DC-to-AC conversion circuit (260) comprises an LLC-based inverter.

7. 3. The inverter device (200) of 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. 3. The inverter device (200) according to claim 1 or 2, wherein the first solar cell (110) includes a crystalline silicon cell, the second solar cell (120) includes a perovskite cell, and the DC-DC conversion circuit (250) includes a DC boost converter.

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

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

11. the first solar cell (110) comprises a crystalline silicon cell located at the bottom of the photovoltaic assembly, and the second solar cell (120) comprises a perovskite cell located at the top of the photovoltaic assembly; or 11. The solar power system (10) of claim 10, wherein the first solar cell (110) comprises a perovskite cell located on a top portion of the solar power assembly, and the second solar cell (120) comprises a crystalline silicon cell located on a bottom portion of the solar power assembly.

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

13. A method for controlling an inverter device (200), comprising: a step (1001) of acquiring first sensing information indicating an output voltage and a current of a first solar cell (110), the first solar cell (110) being coupled to an AC power grid or an appliance (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) a maximum power point of the first solar cell (110) based on the optimal operating voltage of the second solar cell (120) being the desired output voltage of the DC-DC conversion circuit (250) and based on the first sensing information, wherein the optimal operating voltage represents a voltage output by the second solar cell (120) and associated with the maximum power point of the second solar cell (120), and the second solar cell (120) is coupled to the AC power grid or equipment (20) via a second input port (230) of the inverter device (200), an 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 use in the DC-DC conversion circuit (250) based on the optimal operating voltage of the second solar cell (120) and the determined maximum power point of the first solar cell (110).

14. 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 solar cell (120) based on the second sensing information; 14. The method of claim 13, further comprising the step of generating (1103) a second control signal for use in the DC-to-AC conversion circuit (260) based on the determined maximum power point of the second solar cell (120).

15. The method of 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 step of acquiring (1001) first sensing information indicating an output voltage and a current of a first solar cell (110) includes: acquiring a plurality of sub-sensing information indicating output voltages and currents of a plurality of sets of solar cells in the first solar cell (110); The step (1002) of determining the maximum power point of the first solar cell (110) comprises: For each DC-DC converter among the plurality of DC-DC converters (250-1, 250-2, 250-3), determining a desired output voltage corresponding to a corresponding DC-DC converter based on the optimum operating voltage; determining a maximum power point of the corresponding set of solar cells based on the corresponding sub-sensing information and the corresponding desired output voltage; The step (1003) of generating a first control signal for use in the DC-DC conversion circuit (250) comprises: For each DC-DC converter among the plurality of DC-DC converters (250-1, 250-2, 250-3), 16. The method of any one of claims 13 to 15, comprising generating a control signal for a corresponding DC-DC converter based on a maximum power point of a set of solar cells corresponding to that DC-DC converter and the corresponding desired output voltage.

17. A control device (1200) used in an inverter device (200), A processor (1210); A control device (1200) comprising: 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 of any one of claims 13 to 16.

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

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

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