Photovoltaic power optimizer, series system, communication-free operation control method and storage medium

Abstract

The invention discloses a photovoltaic power optimizer, a series system, a communication-free operation control method and a storage medium. The photovoltaic power optimizer comprises an MCU module, a sampling detection module, a driving circuit and a photovoltaic power optimization circuit module, the sampling detection module detects voltage and current of the input end and voltage signals of the output end of the photovoltaic power optimization circuit module in real time; and the MCU module performs logic judgment according to the input end voltage signal, the current signal and the output end voltage signal, and controls the duty ratios of the first to fourth switching tubes through the driving circuit so as to control the photovoltaic power optimizer to operate in a corresponding working mode. According to the invention, the adaptation range of the photovoltaic power optimizer to the inverter is obviously improved, and the hardware cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic power generation technology, and more specifically, relates to a photovoltaic power optimizer, a series system, a communication-free operation control method, and a storage medium. Background Technology

[0002] Solar energy is safe, clean, efficient, sustainable, and widely distributed, leading to the rapid development of the photovoltaic industry. The series-connected power optimizer structure is one of many photovoltaic power generation system structures. The power optimizer controls the output voltage of the photovoltaic cells to achieve maximum power point tracking (MPPT), and the outputs are connected in series to form a DC bus for subsequent system stages. The series-connected power optimizer structure effectively solves mismatch problems caused by shading and module aging, and features modularity, low cost, and high flexibility.

[0003] Commercially available photovoltaic (PV) power optimizers need to communicate with downstream controllers such as inverters or battery management systems (BMS) during operation. This communication allows them to upload relevant PV power generation data, adjust the output voltage and current of individual PV power optimizers to ensure the normal operation of the optimizer's power generation system and the downstream controller, and control the optimizer's startup and shutdown through downstream device policies or user intervention. Different brands of optimizers use different communication protocols and methods with downstream devices, often resulting in communication failures. This prevents power optimizers from being freely compatible with inverters, DC-DC step-up / step-down modules, and BMS battery management systems from different brands. Furthermore, in existing technologies, because the parameter values ​​in the control logic need to be set according to the usage scenario, optimizers without communication capabilities cannot adapt to all usage scenarios, presenting significant limitations. In addition, the optimization startup and control in the existing technology requires a downstream device controller or main control module as the system master controller to control the startup, protection and stable operation of the optimizer, and control the working mode of the optimizer, but this increases the complexity of the system and increases the hardware cost.

[0004] Therefore, it is very important to design a photovoltaic power optimizer that is not limited by communication protocols and methods and can be adapted to multiple brands and devices. Summary of the Invention

[0005] To address the following technical problems existing in the prior art: When a power optimizer is used in conjunction with downstream devices, such as when an inverter is connected to the grid to generate electricity and the battery is being charged via a BMS, the downstream devices need to communicate with the power optimizer in real time to upload data. The downstream devices issue commands to control the optimizer according to their internal policies. If different brands of optimizers cause communication incompatibility, the device cannot be used normally.

[0006] The optimization process requires a downstream device controller or main control module as the system master controller to ensure the optimization's startup, protection, and stable operation, and to control the optimization's working mode. This increases the system's complexity and hardware costs.

[0007] This invention proposes a photovoltaic power optimizer, a series system, a communication-free operation control method, and a storage medium. The startup control process of the power optimizer under communication-free conditions involves detecting the input and output voltages and current of the photovoltaic power optimizer, identifying the operating state of the downstream controller, and using control logic to compare electrical parameters with preset values ​​to determine the next operating mode of the optimizer. This simplifies the overall system control process, expands the optimizer's adaptability to downstream controllers, reduces hardware costs, prevents downtime due to communication failures, and improves system reliability.

[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution.

[0009] This invention discloses a photovoltaic power optimizer, which includes an MCU module, a sampling and detection module, a driving circuit, and a photovoltaic power optimization circuit module; The positive and negative input terminals of the photovoltaic power optimization circuit module are connected to the positive and negative output voltages of the corresponding photovoltaic modules, respectively; the positive output terminal of the photovoltaic power optimization circuit module is connected to the positive terminal of the DC bus or connected in series with the negative output terminal of the adjacent photovoltaic power optimizer in the photovoltaic power optimizer module; the negative output terminal of the photovoltaic power optimization circuit module is connected to the negative terminal of the DC bus or connected in series with the positive output terminal of the adjacent photovoltaic power optimizer in the photovoltaic power optimizer module. The input terminal of the photovoltaic power optimization circuit module includes a series branch consisting of a first switch Q1 and a second switch Q2. The first switch Q1 is connected to the positive terminal of the input terminal of the photovoltaic power optimization circuit module, and the second switch Q2 is connected to the negative terminal of the input terminal of the photovoltaic power optimization circuit module. The output terminal of the photovoltaic power optimization circuit module includes a series branch consisting of a fourth switch Q4 and a third switch Q3. The fourth switch Q4 is connected to the positive terminal of the output terminal of the photovoltaic power optimization circuit module, and the third switch Q3 is connected to the negative terminal of the output terminal of the photovoltaic power optimization circuit module. A first power inductor L1 is connected between the connection point of the first switch Q1 and the second switch Q2 and the connection point of the fourth switch Q4 and the third switch Q3. The sampling and detection module detects the input voltage and current of the photovoltaic power optimization circuit module and the output voltage signal in real time. The MCU module makes logical judgments based on the input voltage, current and output voltage signals, and controls the duty cycle of the first to fourth switching transistors through the drive circuit to control the photovoltaic power optimizer to operate in the corresponding working mode. The working modes include standby mode, pre-start mode and optimization mode.

[0010] More preferably, The photovoltaic power optimization circuit module includes an input filter capacitor and an output filter capacitor connected in parallel at the input and output ends, and a diode connected in reverse parallel at the output end.

[0011] More preferably, When the photovoltaic module supplies power to the photovoltaic power optimizer, the MCU module controls the duty cycle of the first to fourth switching transistors to be 0 through the drive circuit, and the photovoltaic power optimizer enters standby mode.

[0012] More preferably, After the photovoltaic power optimizer enters standby mode, the input and output voltages of the photovoltaic power optimization circuit module are continuously monitored. When the input or output voltage of the photovoltaic power optimization circuit module is greater than or equal to the withstand voltage threshold, the MCU module continues to control the photovoltaic power optimizer to remain in standby mode. Otherwise, the MCU module controls the duty cycle of the first switch Q1 and the fourth switch Q4 to be 1 and the duty cycle of the second switch Q2 and the third switch Q3 to be 0 through the drive circuit, so that the photovoltaic power optimizer enters the pre-start mode.

[0013] More preferably, After the photovoltaic power optimizer enters the pre-start mode, it continuously judges the input and output voltages of the photovoltaic power optimization circuit module. When the input current of the photovoltaic power optimization circuit module is greater than the preset start-up current, the inverter does not work, and the MCU module continues to control the photovoltaic power optimizer to maintain the pre-start state. Otherwise, the MCU module controls the duty cycle of the first to fourth switching transistors to change between 0 and 1 through the drive circuit. The photovoltaic power optimizer judges that the inverter has started working and enters the optimization mode until it finds the point of maximum photovoltaic output power and then stabilizes the output voltage to continue generating electricity.

[0014] More preferably, After the photovoltaic power optimizer enters the optimization mode, it continuously judges the input voltage and output voltage of the photovoltaic power optimization circuit module. If the input current and input voltage of the photovoltaic power optimization circuit module are not simultaneously less than the shading current threshold and the shading voltage threshold, the photovoltaic power optimizer is successfully started; otherwise, it is determined that the photovoltaic module is shaded or the light is insufficient, and the photovoltaic power optimizer is controlled to return to the standby mode.

[0015] On the other hand, the present invention also discloses a photovoltaic power optimizer series system, comprising: The system comprises an inverter, multiple sets of photovoltaic modules, and multiple photovoltaic power optimizers as described above; each set of photovoltaic modules is matched with one photovoltaic power optimizer, and the photovoltaic power optimizers are connected in series and connected to the input terminal of the inverter via a DC bus, and the output terminal of the inverter is connected to the power grid.

[0016] The present invention also discloses a communication-free operation control method for a photovoltaic power optimizer series system as described above, the method comprising the following: Real-time monitoring of the input voltage and current, as well as the output voltage signal of the photovoltaic power optimization circuit module; When the photovoltaic modules supply power to the photovoltaic power optimizer, the photovoltaic power optimizer controls the duty cycle of the first to fourth switching transistors to be 0, and the photovoltaic power optimizer enters standby mode; After the photovoltaic power optimizer enters standby mode, the input and output voltages of the photovoltaic power optimizer are continuously monitored. When the input or output voltage of the photovoltaic power optimizer is greater than or equal to the withstand voltage threshold, the photovoltaic power optimizer continues to maintain standby mode. Otherwise, the photovoltaic power optimizer controls the duty cycle of the first switch Q1 and the fourth switch Q4 to be 1, and the duty cycle of the second switch Q2 and the third switch Q3 to be 0, so that the photovoltaic power optimizer enters pre-start mode. After the photovoltaic power optimizer enters the pre-start mode, it continuously judges the input voltage and output voltage of the photovoltaic power optimizer. When the input current of the photovoltaic power optimizer is greater than the preset start-up current, the inverter does not work, and the photovoltaic power optimizer continues to control the photovoltaic power optimizer to maintain the pre-start state; otherwise, the photovoltaic power optimizer controls the duty cycle of the first to fourth switches to change between 0 and 1. The photovoltaic power optimizer judges that the inverter has started working, and the photovoltaic power optimizer enters the optimization mode until it finds the point of maximum photovoltaic output power and then stabilizes the output voltage to continue generating electricity.

[0017] More preferably, After the photovoltaic power optimizer enters the optimization mode, it continuously judges the input voltage and output voltage of the photovoltaic power optimizer. If the input current and input voltage of the photovoltaic power optimizer are not simultaneously less than the shading current threshold and the shading voltage threshold, the photovoltaic power optimizer is successfully started; otherwise, it is determined that the photovoltaic module is shaded or the light is insufficient, and the photovoltaic power optimizer is controlled to return to the standby mode.

[0018] A computer-readable storage medium having a computer program stored thereon, characterized in that, when executed by a processor, the program implements the steps of a communication-free operation control method for the photovoltaic power optimizer series system.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention identifies the working status of the downstream controller by detecting the input and output voltage and input current of the photovoltaic power optimizer, without relying on communication to determine the working status. It is not limited by communication protocols and does not require the downstream equipment to actively control the photovoltaic power optimizer. It can complete MPPT optimization independently of the downstream equipment and can be adapted to inverters, DC step-up and step-down power supplies, and BMS management systems of different brands.

[0020] 2. The non-communication photovoltaic power optimizer eliminates the communication circuit, reducing hardware costs, preventing communication-related failures, improving reliability, reducing product size, and simplifying the process.

[0021] 3. When making logical judgments on startup, protection, operation, and standby states, the non-communication photovoltaic power optimizer only uses fixed and collectable data, eliminating the need to modify the program based on usage scenario parameters, thus improving versatility and reducing maintenance and installation costs. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the photovoltaic power optimizer connected in series with the subsequent inverter for grid-connected power generation according to the present invention. Figure 2 This is a schematic diagram of the photovoltaic power optimizer topology of the present invention; Figure 3 This invention relates to a photovoltaic power optimizer input-side voltage detection circuit. Figure 4 This invention relates to a photovoltaic power optimizer output-side voltage detection circuit. Figure 5 This invention relates to the photovoltaic power optimizer input-side current detection circuit. Figure 6 This is a schematic diagram of the startup process of a single photovoltaic power optimizer according to the present invention. Detailed Implementation

[0023] 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 embodiments described in this application 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.

[0024] In a series-connected photovoltaic (PV) power optimizer system, each PV module is connected to a corresponding PV power optimizer. The outputs of the PV power optimizers are connected in series, and the sum of the output voltages of all the PV power optimizers equals the DC bus voltage, i.e.: VBUS = Vout1 + Vout2 + Vout3 + ... + Voutn, where Vouti is the output voltage of each photovoltaic power optimizer (i = 1, 2, 3, ..., n), and VBUS is the DC bus voltage.

[0025] Example 1: refer to Figure 2 This is a schematic diagram of the topology of a non-communication photovoltaic power optimizer provided in an embodiment of the present invention, including an MCU module, a sampling and detection module, a driving circuit and a photovoltaic power optimization circuit module.

[0026] Specifically, the input terminal of the photovoltaic power optimization circuit module includes a series branch consisting of a first switch Q1 and a second switch Q2. The first switch Q1 is connected to the positive terminal of the input terminal of the photovoltaic power optimization circuit module, and the second switch Q2 is connected to the negative terminal of the input terminal of the photovoltaic power optimization circuit module. The output terminal of the photovoltaic power optimization circuit module includes a series branch consisting of a fourth switch Q4 and a third switch Q3. The fourth switch Q4 is connected to the positive terminal of the output terminal of the photovoltaic power optimization circuit module, and the third switch Q3 is connected to the negative terminal of the output terminal of the photovoltaic power optimization circuit module. A first power inductor L1 is connected between the connection point of the first switch Q1 and the second switch Q2 and the connection point of the fourth switch Q4 and the third switch Q3.

[0027] Furthermore, such as Figure 3 The diagram shows the input / output voltage detection circuit and the input current detection circuit of a photovoltaic power optimizer provided in an embodiment of the present invention. The input / output voltage detection circuit and the input current detection circuit in the photovoltaic power optimizer respectively collect the input voltage, output voltage, and input current passing through the photovoltaic power optimizer to obtain input voltage sampling data, output voltage sampling data, and input current sampling data.

[0028] Specifically, the input-side voltage detection circuit includes a positive input signal Vin+ connected to the non-inverting input of a first operational amplifier U1 via a first resistor R1, and a negative input signal Vin− connected to the inverting input of U1 via a second resistor R2. The non-inverting input of U1 is connected to the output via a fourth resistor R4. A tenth capacitor C10 is connected in parallel with R4, and a fifth resistor R5 is connected in parallel with an eleventh capacitor C11, with one end connected to the inverting input of U1 and the other end grounded. The output of U1 is connected to a third resistor... R3 Connect to node 7. One end of the third capacitor C3 is connected to node 7, and the other end is grounded.

[0029] The output voltage detection circuit includes a positive input signal Vin+ connected to the non-inverting input of the second operational amplifier U2 via a sixth resistor R6, and a negative input signal Vin− connected to the inverting input of U2 via a seventh resistor R7. The non-inverting input of U2 is connected to the output through an eighth resistor R8. The fourth capacitor C4 is connected in parallel with R8, and the resistor R9 is connected in parallel with the fifth capacitor C5. One end of the resistor R9 is connected to the inverting input of U2, and the other end is grounded. The output of U2 is connected to node 8 via a tenth resistor R10, and one end of the sixth capacitor C6 is connected to node 8, and the other end is grounded.

[0030] The input-side current detection circuit includes a current signal I flowing through a sampling resistor Rsense (at node 6). The resulting positive voltage signal is connected to the non-inverting input of the third operational amplifier U3 via the eleventh resistor R11, and the negative voltage signal is connected to the inverting input of U3 via the twelfth resistor R12. The non-inverting input of U3 is connected to the output via the thirteenth resistor R13. The seventh capacitor C7 is connected in parallel with R13. The fourteenth resistor R14 is connected in series with the capacitor C8, with one end connected to the inverting input of U3 and the other end grounded. The output of U3 is connected to node 9 via resistor R15. One end of the capacitor C9 is connected to node 9 and the other end is grounded.

[0031] The input and output voltages and input current are pulled down to a range that the MCU module can recognize by the operational amplifier. The voltage and current signals are output to the MCU for calculation and analysis through the module output ports 7, 8, and 9. R1=R2, R4=R5, R6=R7, R8=R9, R11=R12, and R13=R14 are set.

[0032] Example 2: refer to Figure 1 The present invention also discloses a photovoltaic power optimizer series system, comprising: multiple photovoltaic modules 101-10n, multiple photovoltaic power optimizers 201-20n, and an inverter 301. Each photovoltaic module is matched with one photovoltaic power optimizer, and the photovoltaic power optimizers are connected in series and then connected to the input terminal of the inverter 301 via a DC bus. The output terminal of the inverter 301 is connected to the power grid 401.

[0033] Example 3: This invention also discloses a photovoltaic power optimizer series system and a communication-free operation control method, comprising the following steps: 31. The sampling and detection module monitors the input voltage and current of the photovoltaic power optimization circuit module, as well as the output voltage signal, in real time. 32. Standby Mode: When sunlight shines on the photovoltaic modules, the MCU controls the PWM signal to make the duty cycle of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4 all D = 0. Q1-Q4 are all in the off state, the main circuit is disconnected, the photovoltaic power optimizer has no output, and the system enters standby mode. After the system enters standby mode, the sampling and detection module starts working, collecting the input voltage Vini, output voltage Vouti, and input current Iini of each photovoltaic power optimizer in real time, and transmitting the sampled data to the MCU module. The MCU module continuously receives the Vini and Vouti data uploaded by the sampling and detection module and compares them with the preset input / output withstand voltage value VH. If Vini > VH or Vouti > VH is detected, it indicates that there is an overvoltage risk in the system. To avoid equipment damage, the photovoltaic power optimizer will remain in standby mode.

[0034] 33. Pre-start Mode: The MCU module controls the drive circuit to output a PWM signal, making the duty cycle D of Q1 and Q4 = 1, and the duty cycle D of Q2 and Q3 = 0. At this time, Q1 and Q4 are in the on state, and Q2 and Q3 are in the off state. At this time, the output voltage Vouti of each photovoltaic power optimizer is equal to the input voltage Vini. The sampling and detection module continuously monitors the input and output voltages of the photovoltaic power optimization circuit module. Once the conditions of Vini < VH and Vouti < VH are met, the system enters the pre-start mode. After the system enters the pre-start mode, it continuously judges the input and output voltages of the photovoltaic power optimization circuit module. When the input current of the photovoltaic power optimization circuit module is greater than the preset starting current, the inverter does not work, and the system continues to maintain the pre-start state.

[0035] 34. Optimization Mode: The MCU module controls the drive circuit to output a PWM signal, causing the duty cycle D of Q1-Q4 to vary between 0 and 1. When VBUS is greater than the inverter's minimum start-up voltage VBUSmin, i.e., Vout1+Vout2+Vout3+...+Voutn>VBUSmin, the inverter starts working. During this process, the sampling and detection module continuously monitors the input current Iini.

[0036] Furthermore, if the photovoltaic module 103 is obstructed, the photovoltaic power optimizer 203 will enter standby mode and output 0V after judgment. If VBUS=Vout1+Vout2+Vout4+…+Voutn is still greater than VBUSmin, the inverter will continue to work; otherwise, the inverter will stop working.

[0037] When the inverter starts working, the output power of the photovoltaic power optimizer increases, causing the input current Iini to rise. When the sampling and detection module detects that Iini is greater than the preset starting current Iq, the photovoltaic power optimizer determines that the inverter has started working and then enters the optimization mode. In the optimization mode, by continuously comparing the output power under different duty cycles, it finds the operating point that maximizes the output power of the photovoltaic modules, realizing the maximum power point tracking function and ensuring that the photovoltaic modules always generate electricity at the highest efficiency.

[0038] After the photovoltaic power optimizer enters the optimization mode, it compares Iini with the shading current threshold IL and Vini with the shading voltage threshold VL. If it is detected that Iini and Vini are not both less than IL and VL at the same time, the photovoltaic power optimizer starts successfully. When it is detected that Iini < IL and Vini < VL, the MCU module determines that the photovoltaic module is severely shaded or in a state of insufficient sunlight, and the photovoltaic power optimizer enters the standby mode and re-detects until it completes the startup.

[0039] Furthermore, once it is determined that the photovoltaic modules are shaded or in a state of insufficient sunlight, the photovoltaic power optimizer immediately enters standby mode. The MCU module starts a timing function, and after timing for 2 minutes, it restarts the detection process to re-evaluate the relationship between Vini, Vouti, and VH, attempting to re-enter the pre-start mode. If the system still cannot generate stable and continuous power after 10 consecutive detection processes, it indicates that the sunlight conditions are continuously poor or there are other serious problems. At this time, the photovoltaic power optimizer enters a 2-hour sleep mode to reduce power consumption. After the sleep mode is completed, the photovoltaic power optimizer re-enters standby mode and repeats the above detection process until the system can start normally and generate power stably.

[0040] Example 4 In Embodiment 4 of the present invention, a non-communication operation control method is disclosed for a photovoltaic power optimizer series system with only one power optimizer, including the following steps: 41. The sampling and detection module detects the input voltage and current of the photovoltaic power optimization circuit module, as well as the output voltage signal, in real time. 42. Standby Mode: When sunlight shines on the photovoltaic modules, the MCU controls the PWM signal to make the duty cycle of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4 all D = 0. Q1-Q4 are all in the off state, the main circuit is disconnected, the photovoltaic power optimizer has no output, and the system enters standby mode. After the system enters standby mode, the sampling and detection module starts working, collecting the input voltage Vin1, output voltage Vout1, and input current Iin1 of each photovoltaic power optimizer in real time, and transmitting the sampled data to the MCU module. The MCU module continuously receives the Vin1 and Vout1 data uploaded by the sampling and detection module and compares them with the preset input / output withstand voltage value VH. If Vin1 > VH or Vout1 > VH is detected, it indicates that there is an overvoltage risk in the system. To avoid equipment damage, the system will remain in standby mode.

[0041] 43. Pre-start Mode: The MCU module controls the drive circuit to output a PWM signal, making the duty cycle D of Q1 and Q4 = 1, and the duty cycle D of Q2 and Q3 = 0. At this time, Q1 and Q4 are in the on state, and Q2 and Q3 are in the off state. At this time, the output voltage Vout1 of each photovoltaic power optimizer is equal to the input voltage Vin1. The sampling and detection module continuously monitors the input and output voltages of the photovoltaic power optimization circuit module. Once the conditions Vin1 < VH and Vout1 < VH are met, the system enters the pre-start mode. After the system enters the pre-start mode, it continuously judges the input and output voltages of the photovoltaic power optimization circuit module. When the input current of the photovoltaic power optimization circuit module is greater than the preset starting current, the inverter does not work, and the system continues to maintain the pre-start state.

[0042] 44. Optimization Mode: The MCU module controls the drive circuit to output a PWM signal, causing the duty cycle D of Q1-Q4 to vary between 0 and 1. When VBUS is greater than the inverter's minimum startup voltage VBUSmin, i.e., Vout1 > VBUSmin, the inverter starts working. During this process, the sampling and detection module continuously monitors the input current Iin1.

[0043] When the inverter starts working, the output power of the photovoltaic power optimizer increases, causing the input current Iin1 to rise. When the sampling and detection module detects that Iin1 is greater than the preset starting current Iq, the photovoltaic power optimizer determines that the inverter has started working and then enters the optimization mode. In the optimization mode, by continuously comparing the output power under different duty cycles, it finds the operating point that maximizes the output power of the photovoltaic modules, realizing the maximum power point tracking function and ensuring that the photovoltaic modules always generate electricity at the highest efficiency.

[0044] After the photovoltaic power optimizer enters the optimization mode, it compares Iin1 with the shading current threshold IL and Vini with the shading voltage threshold VL. If it is detected that Iin1 and Vin1 are not both less than IL and VL at the same time, the photovoltaic power optimizer starts successfully. When it is detected that Iin1 < IL and Vin1 < VL, the MCU module determines that the photovoltaic module is severely shaded or in a state of insufficient sunlight, and the photovoltaic power optimizer enters the standby mode and re-detects until it completes the startup.

[0045] Furthermore, once it is determined that the photovoltaic modules are shaded or in a state of insufficient sunlight, the photovoltaic power optimizer immediately enters standby mode. The MCU module starts a timing function, and after timing for 2 minutes, it restarts the detection process to re-evaluate the relationship between Vin1, Vout1, and VH, attempting to re-enter the pre-start mode. If the system still cannot generate stable and continuous power after 10 consecutive detection processes, it indicates that the sunlight conditions are continuously poor or there are other serious problems. At this time, the photovoltaic power optimizer enters a 2-hour sleep mode to reduce power consumption. After the sleep mode is completed, the photovoltaic power optimizer re-enters standby mode and repeats the above detection process until the system can start normally and generate power stably.

[0046] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0047] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0048] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0049] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0050] 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 power optimizer, characterized in that: Includes an MCU module, a sampling and detection module, a drive circuit, and a photovoltaic power optimization circuit module; The positive and negative input terminals of the photovoltaic power optimization circuit module are connected to the positive and negative output voltages of the corresponding photovoltaic modules, respectively; the positive output terminal of the photovoltaic power optimization circuit module is connected to the positive terminal of the DC bus or connected in series with the negative output terminal of the adjacent photovoltaic power optimizer in the photovoltaic power optimizer module; the negative output terminal of the photovoltaic power optimization circuit module is connected to the negative terminal of the DC bus or connected in series with the positive output terminal of the adjacent photovoltaic power optimizer in the photovoltaic power optimizer module. The input terminal of the photovoltaic power optimization circuit module includes a series branch consisting of a first switch Q1 and a second switch Q2. The first switch Q1 is connected to the positive terminal of the input terminal of the photovoltaic power optimization circuit module, and the second switch Q2 is connected to the negative terminal of the input terminal of the photovoltaic power optimization circuit module. The output terminal of the photovoltaic power optimization circuit module includes a series branch consisting of a fourth switch Q4 and a third switch Q3. The fourth switch Q4 is connected to the positive terminal of the output terminal of the photovoltaic power optimization circuit module, and the third switch Q3 is connected to the negative terminal of the output terminal of the photovoltaic power optimization circuit module. A first power inductor L1 is connected between the connection point of the first switch Q1 and the second switch Q2 and the connection point of the fourth switch Q4 and the third switch Q3. The sampling and detection module detects the input voltage and current of the photovoltaic power optimization circuit module and the output voltage signal in real time. The MCU module makes logical judgments based on the input voltage, current and output voltage signals, and controls the duty cycle of the first to fourth switching transistors through the drive circuit to control the photovoltaic power optimizer to operate in the corresponding working mode. The working modes include standby mode, pre-start mode and optimization mode.

2. The photovoltaic power optimizer according to claim 1, characterized in that: The photovoltaic power optimization circuit module includes an input filter capacitor and an output filter capacitor connected in parallel at the input and output ends, and a diode connected in reverse parallel at the output end.

3. The photovoltaic power optimizer according to claim 1, characterized in that: When the photovoltaic module supplies power to the photovoltaic power optimizer, the MCU module controls the duty cycle of the first to fourth switching transistors to be 0 through the drive circuit, and the photovoltaic power optimizer enters standby mode.

4. The photovoltaic power optimizer according to claim 3, characterized in that: After the photovoltaic power optimizer enters standby mode, the input and output voltages of the photovoltaic power optimization circuit module are continuously monitored. When the input or output voltage of the photovoltaic power optimization circuit module is greater than or equal to the withstand voltage threshold, the MCU module continues to control the photovoltaic power optimizer to remain in standby mode. Otherwise, the MCU module controls the duty cycle of the first switch Q1 and the fourth switch Q4 to be 1 and the duty cycle of the second switch Q2 and the third switch Q3 to be 0 through the drive circuit, so that the photovoltaic power optimizer enters the pre-start mode.

5. The photovoltaic power optimizer according to claim 4, characterized in that: After the photovoltaic power optimizer enters the pre-start mode, it continuously judges the input and output voltages of the photovoltaic power optimization circuit module. When the input current of the photovoltaic power optimization circuit module is greater than the preset start-up current, the inverter does not work, and the MCU module continues to control the photovoltaic power optimizer to maintain the pre-start state. Otherwise, the MCU module controls the duty cycle of the first to fourth switching transistors to change between 0 and 1 through the drive circuit. The photovoltaic power optimizer judges that the inverter has started working and enters the optimization mode until it finds the point of maximum photovoltaic output power and then stabilizes the output voltage to continue generating electricity.

6. The photovoltaic power optimizer according to claim 5, characterized in that: After the photovoltaic power optimizer enters the optimization mode, it continuously judges the input voltage and output voltage of the photovoltaic power optimization circuit module. If the input current and input voltage of the photovoltaic power optimization circuit module are not simultaneously less than the shading current threshold and the shading voltage threshold, the photovoltaic power optimizer is successfully started; otherwise, it is determined that the photovoltaic module is shaded or the light is insufficient, and the photovoltaic power optimizer is controlled to return to the standby mode.

7. A photovoltaic power optimizer series system, characterized in that, include: The system comprises an inverter, multiple sets of photovoltaic modules, and multiple photovoltaic power optimizers as described in claim 1; each set of photovoltaic modules is matched with one photovoltaic power optimizer, and the photovoltaic power optimizers are connected in series and connected to the input terminal of the inverter via a DC bus, and the output terminal of the inverter is connected to the power grid.

8. A communication-free operation control method for a photovoltaic power optimizer series system as described in claim 7, characterized in that, The method includes the following: Real-time monitoring of the input voltage and current, as well as the output voltage signal of the photovoltaic power optimization circuit module; When the photovoltaic modules supply power to the photovoltaic power optimizer, the photovoltaic power optimizer controls the duty cycle of the first to fourth switching transistors to be 0, and the photovoltaic power optimizer enters standby mode; After the photovoltaic power optimizer enters standby mode, the input and output voltages of the photovoltaic power optimizer are continuously monitored. When the input or output voltage of the photovoltaic power optimizer is greater than or equal to the withstand voltage threshold, the photovoltaic power optimizer continues to maintain standby mode. Otherwise, the photovoltaic power optimizer controls the duty cycle of the first switch Q1 and the fourth switch Q4 to be 1, and the duty cycle of the second switch Q2 and the third switch Q3 to be 0, so that the photovoltaic power optimizer enters pre-start mode. After the photovoltaic power optimizer enters the pre-start mode, it continuously judges the input voltage and output voltage of the photovoltaic power optimizer. When the input current of the photovoltaic power optimizer is greater than the preset start-up current, the inverter does not work, and the photovoltaic power optimizer continues to control the photovoltaic power optimizer to maintain the pre-start state; otherwise, the photovoltaic power optimizer controls the duty cycle of the first to fourth switches to change between 0 and 1. The photovoltaic power optimizer judges that the inverter has started working, and the photovoltaic power optimizer enters the optimization mode until it finds the point of maximum photovoltaic output power and then stabilizes the output voltage to continue generating electricity.

9. The non-communication operation control method for a photovoltaic power optimizer series system according to claim 8, characterized in that: After the photovoltaic power optimizer enters the optimization mode, it continuously judges the input voltage and output voltage of the photovoltaic power optimizer. If the input current and input voltage of the photovoltaic power optimizer are not simultaneously less than the shading current threshold and the shading voltage threshold, the photovoltaic power optimizer is successfully started; otherwise, it is determined that the photovoltaic module is shaded or the light is insufficient, and the photovoltaic power optimizer is controlled to return to the standby mode.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the method according to any one of claims 8-9.

Images