A photovoltaic optimization system and a control method thereof

Abstract

A photovoltaic optimization system and a control method thereof, the photovoltaic optimization system comprising: a photovoltaic assembly, a photovoltaic optimization device, and an inverter; the photovoltaic assembly is connected with the photovoltaic optimization device; a plurality of photovoltaic optimization devices are connected in series and then connected with the inverter; the photovoltaic optimization device comprises a four-switch bidirectional buck-boost topology, two bootstrap drive modules, and a master control chip; the photovoltaic optimization device controls the drive waveform of four power switching devices in the four-switch bidirectional buck-boost topology through the bootstrap drive module based on the sampling result, adjusts the working mode, including: when the photovoltaic optimization system does not exist fault, according to the comparison result of the output voltage and the input voltage of the photovoltaic optimization device, the corresponding normal mode is executed; when the photovoltaic optimization system exists fault, according to the fault type, the corresponding fault mode is executed. The present application has high efficiency, low loss, flexible control, comprehensive function, good adaptability, and can adapt to various types of photovoltaic assemblies and inverters.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic optimization technology, and more specifically, relates to a photovoltaic optimization system and its control method. Background Technology

[0002] Existing photovoltaic (PV) optimization systems typically employ the traditional MPPT+BUCK circuit method to optimize the output power of PV modules. However, this traditional method has several drawbacks, including but not limited to a narrow optimization voltage range, limited adaptability, and difficulty in achieving efficient power point tracking under complex lighting conditions, shading, and dynamic system changes, resulting in low system power generation efficiency.

[0003] Existing technical documents provide solutions, such as, but not limited to, a high-efficiency solar photovoltaic power generation control system and method. In this system, the voltage conversion circuit of each synchronous BUCK unit independently controls the maximum power point tracking (MPPT) of each photovoltaic panel group to optimize the output of each panel group. However, due to the limitations of its BUCK topology, this system has a slow dynamic response and its input and output voltages can only vary within a small range. Therefore, this system can only be adapted to fixed types of photovoltaic modules and inverters, and cannot be adapted to other types of photovoltaic modules and inverters, making it too limited. Existing technical documents also provide a method to perform secondary perturbation on the photovoltaic strings through a voltage regulation unit to optimize the output of each string and reduce efficiency losses caused by parallel mismatch. The voltage regulation unit is connected in the power transmission loop of the photovoltaic string, enabling maximum power point tracking without significantly increasing power loss. An electronically controlled switch is introduced to optimize system efficiency by switching the switch state, while also supporting the integration of energy storage systems. The solutions in the existing technical documents also include: using a synchronous BUCK unit voltage conversion circuit, combined with a PI regulator and Parker inverse converter, to achieve high-efficiency maximum power point tracking through analysis and processing of historical data, and to optimize the output of photovoltaic panels through voltage conversion and control algorithms to reduce system oscillation problems and improve overall conversion efficiency, but the algorithm implementation is complex. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a photovoltaic optimization system and its control method, which applies a four-switch bidirectional buck-boost topology (FSBB) to the photovoltaic system, solving the problems of narrow optimization voltage range, poor adaptability, and slow dynamic response in traditional photovoltaic systems.

[0005] The present invention adopts the following technical solution.

[0006] A first aspect of the present invention provides a photovoltaic optimization system, including a photovoltaic module, a photovoltaic optimization device, and an inverter;

[0007] The photovoltaic module is connected to the photovoltaic optimization device;

[0008] Multiple sets of the photovoltaic optimization devices are connected in series and then connected to the inverter;

[0009] The photovoltaic optimization device includes a four-switch bidirectional buck-boost topology, two bootstrap drive modules, and a main control chip.

[0010] Based on the sampling results, the photovoltaic optimization device controls the driving waveforms of the four power switching devices in the four-switch bidirectional buck-boost topology through the bootstrap driving module to adjust the working mode, including: when there is no fault in the photovoltaic optimization system, executing the corresponding normal mode according to the comparison results of the output voltage and input voltage of the photovoltaic optimization device; when there is a fault in the photovoltaic optimization system, executing the corresponding fault mode according to the fault type.

[0011] Preferably, the four-switch bidirectional buck-boost topology includes:

[0012] High-side power switching devices: power switching device Q1 and power switching device Q3;

[0013] Low-side power switching devices: power switching device Q2 and power switching device Q4;

[0014] The power switching device Q1 and the power switching device Q2 share a bootstrap driving module, and the power switching device Q3 and the power switching device Q4 share a bootstrap driving module.

[0015] Preferably, a mid-range voltage balancing point is added between the high-end output and the low-end output of the bootstrap driving module, and a bootstrap capacitor is connected between the high-end output and the mid-range voltage balancing point; the high-end output is connected to the gate of the high-side power switching device, the low-end output is connected to the gate of the low-side power switching device, and the mid-range voltage balancing point is connected to the source of the high-side power switching device.

[0016] Preferably, the main control chip provides a complementary PWM waveform to the bootstrap drive module. The low-side input of the bootstrap drive module is boosted by an auxiliary power supply signal to drive the low-side power switching device. The high-side input of the bootstrap drive module generates a gate drive through the charging and discharging of the bootstrap capacitor to drive the high-side power switching device. The operating mode is adjusted by adjusting the on / off state of the power switching device.

[0017] Preferably, the photovoltaic optimization system uses power line carrier communication.

[0018] A second aspect of the present invention provides a control method for a photovoltaic optimization system, based on a photovoltaic optimization system as described in the first aspect of the present invention, comprising the following steps:

[0019] Initialize the photovoltaic optimization system and collect the input and output signals of the photovoltaic optimization device in real time;

[0020] Based on the sampling results, the bootstrap driving module controls the driving waveforms of the four power switching devices in the four-switch bidirectional buck-boost topology, adjusts the on / off state of the power switching devices, and dynamically adjusts the operating mode. This includes executing the corresponding normal mode when there is no fault in the photovoltaic optimization system by comparing the output voltage and input voltage of the photovoltaic optimization device; and executing the corresponding fault mode according to the fault type when there is a fault in the photovoltaic optimization system.

[0021] Preferably, the normal mode includes:

[0022] When the output voltage of the photovoltaic optimization device is equal to the input voltage, the direct-through mode is executed.

[0023] When the output voltage is less than the input voltage, the buck optimization mode in MPPT mode is executed.

[0024] When the output voltage is greater than the input voltage, the boost optimization mode in MPPT mode is executed.

[0025] The failure modes include:

[0026] When a recoverable fault occurs in the photovoltaic optimization system, bypass mode is executed.

[0027] When an unrecoverable fault occurs in the photovoltaic optimization system, the protection mode is executed.

[0028] Preferably, the pass-through mode includes: driving the power switching device Q1 and the power switching device Q3 to pass through with a set duty cycle, and driving the power switching device Q2 and the power switching device Q4 to bootstrap with a set duty cycle;

[0029] The buck optimization mode in the MPPT mode includes: driving the power switch Q1 and the power switch Q2 to turn on complementaryly, the power switch Q3 to be directly turned on with a set duty cycle, and the power switch Q4 to be self-driven with a set duty cycle.

[0030] The boost optimization mode in the MPPT mode includes: driving the power switch Q1 to pass through with a set duty cycle, driving the power switch Q2 to bootstrap with a set duty cycle, and turning on the power switch Q3 and the power switch Q4 complementaryly.

[0031] The bypass mode includes: driving all power switching devices Q1, Q2, Q3 and Q4 to turn off;

[0032] The protection mode includes: shutting down all photovoltaic optimization systems.

[0033] A third aspect of the present invention provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program, when loaded onto the processor, implements a control method for a photovoltaic optimization system as described in the second aspect of the present invention.

[0034] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements a control method for a photovoltaic optimization system as described in the second aspect of the present invention.

[0035] Compared with existing technologies, this invention proposes a photovoltaic optimization system based on a series connection of photovoltaic optimization devices using an FSBB topology. It introduces bootstrap driving technology under a four-switch topology and employs a four-switch photovoltaic modulation strategy, utilizing the volt-ampere characteristics of the photovoltaic panels in conjunction with the four switches for multi-mode control. The beneficial effects of this invention include at least:

[0036] 1. High efficiency and low loss: By using bootstrap driving technology and MPPT multi-switch modulation, hardware costs are reduced, switching losses are reduced, the overall efficiency of the system is improved, electromagnetic interference and power loss during the switching process are reduced, and the reliability of the system is enhanced.

[0037] 2. Flexible control and comprehensive functions: It supports bidirectional energy flow and boost / buck functions, enabling the system to respond quickly under complex lighting conditions and shadows, making it suitable for a variety of application scenarios.

[0038] 3. It has good adaptability and can be adapted to various types of photovoltaic modules and inverters. Attached Figure Description

[0039] Figure 1 This is a block diagram of a series photovoltaic optimization system provided according to an embodiment of the present invention;

[0040] Figure 2 These are the topology diagram and bootstrap drive circuit diagram of the photovoltaic optimization device provided in accordance with the embodiments of the present invention;

[0041] Figure 3 This is a flowchart of the photovoltaic optimization process provided in accordance with an embodiment of the present invention;

[0042] Figure 4 This is an adaptive mode judgment flowchart provided according to an embodiment of the present invention.

[0043] exist Figure 1 In the diagram, 1 represents a photovoltaic module; 2 represents a photovoltaic optimization device; 3 represents an inverter; 4 represents a signal coupling magnetic ring; and 5 represents a power line carrier device.

[0044] exist Figure 2 In this diagram, Q1, Q2, Q3, and Q4 represent the first, second, third, and fourth power switching devices; L1 represents the inductor; C1 represents the capacitor; HI represents the high-side input; LI represents the low-side input; 6 represents the high-side output; 7 represents the low-side output; 8 represents the mid-side voltage balance point; and 9 represents the bootstrap capacitor. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0046] Embodiment 1 of the present invention provides a photovoltaic optimization system, the system including a photovoltaic module, a photovoltaic optimization device, and an inverter.

[0047] like Figure 1 As shown, the positive and negative terminals of the photovoltaic module 1 are connected to the positive and negative terminals of the photovoltaic optimization device 2, and multiple sets of the photovoltaic optimization devices are connected in series. After being connected in series, the total positive terminal is connected to the positive terminal of the inverter 3, and the total negative terminal is connected to the negative terminal of the inverter 3.

[0048] like Figure 2 As shown, the photovoltaic optimization device adopts a four-switch bidirectional buck-boost topology. This topology, as a novel circuit structure, enables efficient power conversion over a wide voltage range and possesses excellent dynamic response characteristics. The photovoltaic optimization device includes power switching devices Q1, Q2, Q3, and Q4, an inductor L1, a capacitor C1, and two bootstrap drive modules.

[0049] A mid-range voltage balancing point 8 is added between the high-end output 6 and the low-end output 7 of the bootstrap drive module, and a bootstrap capacitor 9 is connected between the high-end output 6 and the mid-range voltage balancing point 8. The high-end output 6 is powered by the bootstrap capacitor 9 and the mid-range voltage balancing point 8, while the low-end output 7 sacrifices a certain duty cycle to support the bootstrap of the high-end output 6. By rationally configuring switching devices and passive components, bidirectional energy flow and buck-boost functions are achieved.

[0050] Specifically, power switching devices Q1 and Q2 share a bootstrap drive module, and power switching devices Q3 and Q4 share a bootstrap drive module. The high-side output 6 is connected to the gate of the high-side switch, the low-side output 7 is connected to the gate of the low-side switch, and the mid-side voltage balance point 8 is connected at the intersection of the source of the high-side switch, the drain of the low-side switch, and the inductor L1. It can be understood that at this time, one end of the bootstrap capacitor 9 is connected to the gate of the high-side switch, and the other end is connected to the drain of the low-side switch. The operation of the bootstrap capacitor is, for example but not limited to: when the low-side power switch Q2 is turned on and the high-side power switch Q1 is turned off, the bootstrap capacitor is charged to Vcc through the conduction path of the power switch Q2; when the low-side power switch Q2 is turned off and the high-side power switch Q1 is turned on, the bootstrap capacitor discharges through the gate-source of the power switch Q1, providing voltage to the gate. The gate voltage is higher than the source voltage, ensuring that the power switch Q1 is fully turned on; the low-side power switch Q2 is periodically turned on to charge the bootstrap capacitor, and the high-side power switch Q1 is periodically turned on to drive the discharge of the bootstrap capacitor.

[0051] It should be noted that, since the voltage range of unipolar modulation in the photovoltaic optimization device is smaller compared to that of bipolar modulation, and the switching loss is larger, the present invention adopts bipolar modulation.

[0052] The input signal of the bootstrap drive module comes directly from the main control chip, which outputs a 3.3V complementary PWM waveform. The low-side input LI is boosted to 3.3V via a 12V auxiliary power supply to meet the driving requirements of the low-side power switching devices. The high-side input HI dynamically generates a gate drive higher than the bus voltage through the charging and discharging mechanism of the bootstrap capacitor, which is used to drive the high-side power switching devices. This driving method requires only one auxiliary power supply and eliminates the need for an additional isolation power supply, reducing the input of two power supplies in a 4-switch topology and lowering hardware costs. It is understood that, similar to traditional photovoltaic optimization devices, this photovoltaic optimization device can be adapted to various photovoltaic modules and inverters. Furthermore, the photovoltaic optimization device can make protection judgments based on its own state and the state of the connected photovoltaic modules, and take corresponding protection measures without affecting the normal operation of other photovoltaic modules and the photovoltaic optimization device itself.

[0053] The inverter can be a photovoltaic inverter or a conventional inverter.

[0054] Preferably, but not limitingly, when the inverter is a photovoltaic inverter, it operates in shoot-through mode under unobstructed and sufficient sunlight conditions. In shoot-through mode, the output voltage is approximately equal to the input voltage. Power switching devices Q1 and Q3 are similar to normally open, for example, but not limited to, a duty cycle of 99.5%. Power switching devices Q2 and Q4 are used for bootstrapping drive with a very small duty cycle, for example, but not limited to, a duty cycle of 0.5%. Under shading or low light conditions, it operates in MPPT mode, adjusting the voltage boost or buck according to the inverter's operating range to adapt to the optimal operating state of different inverter models and photovoltaic modules. Preferably, but not limited to, the buck optimization mode in MPPT mode is operated, where the input voltage is greater than the output voltage, the power switching devices Q1 and Q2 are complementaryly turned on, the optimization range is preferably, but not limited to, 10%-90%, the power switching device Q3 is similar to normally open, for example, but not limited to, a duty cycle of 99.5%, and the power switching device Q4 is used for bootstrapping drive with a very small duty cycle, for example, but not limited to, a duty cycle of 0.5%.

[0055] When the inverter is a conventional inverter, buck-boost conversion is performed simultaneously with MPPT optimization based on the DC voltage at the inverter terminal and the number of photovoltaic panel strings. Preferably, but not limitingly, the boost optimization mode in MPPT is operated, where the output voltage is greater than the input voltage. Power switch Q1 is similar to normally open, for example, but not limited to, a duty cycle of 99.5%. Power switch Q2 is used for bootstrapping drive with a very small duty cycle, for example, but not limited to, a duty cycle of 0.5%. Power switch Q3 and power switch Q4 are complementary in operation. The optimization range is preferably, but not limitingly, 10%-90%.

[0056] Preferably, but not limitingly, the photovoltaic optimization system uses power line carrier communication, does not require an additional communication interface, can independently transmit data via the Internet, and can also be adapted to various communication methods of other inverters, such as mainstream communication methods like RS485.

[0057] like Figure 3 As shown, Embodiment 2 of the present invention provides a control method for a photovoltaic optimization system, which controls the photovoltaic optimization system described in Embodiment 1 of the present invention, including the following steps:

[0058] Step 1: Initialize the system and acquire signals in real time;

[0059] Preferably, but not limitingly, the system is initialized. After initialization, the power switching devices Q1 and Q3 are in a near-shoot-through state, i.e., the duty cycle is close to 100%. The power switching devices Q2 and Q4 are started with a very small duty cycle to supply power to the bootstrap capacitor and maintain the conduction of the two high-side switches, i.e., the power switching devices Q1 and Q3.

[0060] Further preferred, but not limiting, the target signal is acquired in real time by ADC sampling and digitally processed. The target signal includes the input voltage and current, output voltage and current of the photovoltaic optimization device. After the sampled data is mean filtered, the power is calculated according to P=U*I. The power change is calculated by the MPPT algorithm, and the magnitude of the input and output voltages is compared to control the change of the duty cycle of the four power switching devices.

[0061] Step 2: Based on the sampling results, adjust the on / off state of the power switching device to dynamically adjust the working mode to adapt to different working conditions;

[0062] Preferred, but not limiting, such as Figure 4 As shown, the device can switch between direct-through mode, bypass mode, protection mode, and MPPT mode according to its status. In the series photovoltaic optimization system, relevant judgments are made by judging the power magnitude and the trend of the derivative of voltage and current with respect to time.

[0063] Specifically, the modes include fault mode and normal mode. The fault mode includes bypass mode and protection mode depending on the fault condition. When a recoverable fault occurs in the photovoltaic optimization system, such as but not limited to over-temperature, over-voltage, under-voltage, and over-current, the photovoltaic optimization device in the faulty part enters the bypass mode: at this time, power switching devices Q1, Q2, Q3, and Q4 are all turned off, bypassing the photovoltaic modules connected to the photovoltaic optimization device. After the fault is recovered, the devices are turned back on, allowing the photovoltaic modules to be reconnected to the system.

[0064] If an unrecoverable fault occurs in the photovoltaic optimization system, such as, but not limited to, hardware overcurrent or sensor failure, the photovoltaic optimization system will enter the protection mode: at this time, the entire system will be shut down, and the series bus voltage will drop rapidly to a safe range, allowing staff to eliminate the potential hazard.

[0065] In the normal operating mode, the input and output voltages are first compared. When the output voltage is approximately equal to the input voltage, the system is in the pass-through mode. Power switches Q1 and Q3 are normally open, for example, but not limited to, with a duty cycle of 99.5%. Power switches Q2 and Q4 are used for bootstrapping with a very small duty cycle, for example, but not limited to, 0.5%. When the input voltage is greater than the output voltage, the system is in the buck optimization mode within the MPPT mode. This mode is typically used when there is local shading. In this mode, power switches Q1 and Q2 are complementary, with an optimization range preferably but not limited to 10%-90%. Power switch Q3 is normally open, for example, but not limited to, with a duty cycle of 99.5%. Power switch Q4 is turned on with a very small duty cycle for bootstrapping, for example, but not limited to, 0.5%. When the output voltage is greater than the input voltage, the system operates in the boost optimization mode within the MPPT mode. This mode is commonly used in ordinary inverters, where the bus voltage is fixed and the photovoltaic voltage is insufficient for direct drive. In this mode, power switch Q1 operates similarly to a normally open state, for example, but not limited to, a duty cycle of 99.5%. Power switch Q2 is used for bootstrapping drive with a very small duty cycle, for example, but not limited to, a duty cycle of 0.5%. Power switches Q3 and Q4 are complementary in operation, with the optimization range preferably, but not limited to, 10%-90%. It is understood that in the photovoltaic optimization system, further judgment and mode selection are needed based on changes in input power and output current according to the type of inverter connected. This invention can perform intelligent mode dynamic judgment and switching processing based on the adapted photovoltaic modules and inverters to ensure that each device is in its optimal operating state.

[0066] The signal output is optimized by using four-switch control technology. The signal is a drive waveform signal used to drive the power switching device, which reduces electromagnetic interference and improves efficiency. The drive output module transmits the processed signal to the actuator to ensure the precise execution of the control action.

[0067] When switching between the normal modes, soft-switching modulation is used, which involves PFM frequency down-modulation, a delay, and then resuming the original frequency for PWM modulation after stabilization. The soft-switching modulation is mainly used when switching modes within the normal mode. Specifically, when the photovoltaic optimization system determines that it needs to enter the direct-through mode, it first performs PFM frequency down-modulation, delays for a period, and then resumes the original frequency for PWM modulation after stabilization. During the frequency down-modulation, the drive signal phase remains unchanged.

[0068] Throughout the control process of the photovoltaic optimization system, protection logic is used to monitor the system status in real time to prevent abnormal situations from occurring. When a fault occurs, the system switches to the bypass mode and the protection mode to ensure the safety and reliability of the system.

[0069] Embodiment 3 of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is loaded onto the processor, it implements a photovoltaic optimization system and its control method according to Embodiments 1 and 2.

[0070] Embodiment 4 of the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements a photovoltaic optimization system and its control method according to Embodiments 1 and 2.

[0071] It is worth noting that in the embodiments of the present invention, "steps + numbers" is only an expression for clearly describing a specific implementation of a photovoltaic optimization system and its control method, and is not an absolute restriction on the order of the steps. Under the guidance of the core concept of the present invention, changing the order of these steps to obtain the same or similar technical effects all fall within the scope of the present invention.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A photovoltaic optimization system, characterized in that, This includes photovoltaic modules, photovoltaic optimization devices, and inverters; The photovoltaic module is connected to the photovoltaic optimization device; Multiple sets of the photovoltaic optimization devices are connected in series and then connected to the inverter; The photovoltaic optimization device includes a four-switch bidirectional buck-boost topology, two bootstrap drive modules, and a main control chip. Based on the sampling results, the photovoltaic optimization device controls the driving waveforms of the four power switching devices in the four-switch bidirectional buck-boost topology through the bootstrap driving module to adjust the working mode, including: when there is no fault in the photovoltaic optimization system, executing the corresponding normal mode according to the comparison results of the output voltage and input voltage of the photovoltaic optimization device; when there is a fault in the photovoltaic optimization system, executing the corresponding fault mode according to the fault type.

2. The photovoltaic optimization system according to claim 1, characterized in that: The four-switch bidirectional buck-boost topology includes: High-side power switching devices: power switching device Q1 and power switching device Q3; Low-side power switching devices: power switching device Q2 and power switching device Q4; The power switching device Q1 and the power switching device Q2 share a bootstrap driving module, and the power switching device Q3 and the power switching device Q4 share a bootstrap driving module.

3. The photovoltaic optimization system according to claim 2, characterized in that: A mid-range voltage balancing point is added between the high-end output and the low-end output of the bootstrap drive module, and a bootstrap capacitor is connected between the high-end output and the mid-range voltage balancing point; the high-end output is connected to the gate of the high-side power switch device, the low-end output is connected to the gate of the low-side power switch device, and the mid-range voltage balancing point is connected to the source of the high-side power switch device.

4. A photovoltaic optimization system according to any one of claims 1 to 3, characterized in that: The main control chip provides complementary PWM waveforms to the bootstrap drive module. The low-side input of the bootstrap drive module is boosted by an auxiliary power supply signal to drive the low-side power switching device. The high-side input of the bootstrap drive module generates gate drive through the charging and discharging of the bootstrap capacitor to drive the high-side power switching device. The operating mode is adjusted by adjusting the on / off state of the power switching device.

5. A photovoltaic optimization system according to claim 1, characterized in that: The photovoltaic optimization system uses power line carrier communication.

6. A control method for a photovoltaic optimization system, based on a photovoltaic optimization system as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Initialize the photovoltaic optimization system and collect the input and output signals of the photovoltaic optimization device in real time; Based on the sampling results, the bootstrap driving module controls the driving waveforms of the four power switching devices in the four-switch bidirectional buck-boost topology, adjusts the on / off state of the power switching devices, and dynamically adjusts the operating mode. This includes executing the corresponding normal mode when there is no fault in the photovoltaic optimization system by comparing the output voltage and input voltage of the photovoltaic optimization device; and executing the corresponding fault mode according to the fault type when there is a fault in the photovoltaic optimization system.

7. The control method for a photovoltaic optimization system according to claim 6, characterized in that: The normal mode includes: When the output voltage of the photovoltaic optimization device is equal to the input voltage, the direct-through mode is executed. When the output voltage is less than the input voltage, the buck optimization mode in MPPT mode is executed. When the output voltage is greater than the input voltage, the boost optimization mode in MPPT mode is executed. The failure modes include: When a recoverable fault occurs in the photovoltaic optimization system, bypass mode is executed. When an unrecoverable fault occurs in the photovoltaic optimization system, the protection mode is executed.

8. A control method for a photovoltaic optimization system according to claim 6 or 7, characterized in that: The pass-through mode includes: driving the power switch device Q1 and the power switch device Q3 to pass through with a set duty cycle, and driving the power switch device Q2 and the power switch device Q4 to bootstrap with a set duty cycle. The buck optimization mode in the MPPT mode includes: driving the power switch Q1 and the power switch Q2 to turn on complementaryly, the power switch Q3 to be directly turned on with a set duty cycle, and the power switch Q4 to be self-driven with a set duty cycle. The boost optimization mode in the MPPT mode includes: driving the power switch Q1 to pass through with a set duty cycle, driving the power switch Q2 to bootstrap with a set duty cycle, and turning on the power switch Q3 and the power switch Q4 complementaryly. The bypass mode includes: driving all power switching devices Q1, Q2, Q3 and Q4 to turn off; The protection mode includes: shutting down all photovoltaic optimization systems.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that... ； When the computer program is loaded into the processor, it implements a control method for a photovoltaic optimization system according to any one of claims 6 to 8.

10. A computer-readable storage medium storing a computer program, characterized in that... ； When the computer program is executed by the processor, it implements a control method for a photovoltaic optimization system according to any one of claims 6 to 8.

Images