Distributed photovoltaic power generation adaptive conversion control method

Abstract

The invention discloses a distributed photovoltaic power generation adaptive conversion control method, which is characterized in that an internal power grid is established among users of each photovoltaic power generation device by adopting a direct current bus, the output power of each photovoltaic power generation device is boosted and then accessed to the direct current bus, and the direct current bus is connected with electric equipment of each user and supplies power to the electric equipment. Meanwhile, the voltage of the direct-current bus is detected, when the voltage of the direct-current bus is higher than 240 V, the direct-current bus is controlled to output power to the external power source, and when the voltage of the direct-current bus is lower than 220 V, the external power source is controlled to input power to the direct-current bus. The system is suitable for rural photovoltaic equipment users to use, the users can conveniently realize photovoltaic power supply and external power output, the control cost can be reduced, and the carbon emission index of rural building energy consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic power systems, and in particular to a distributed photovoltaic power generation adaptive conversion control method. Background Art

[0002] Energy consumption in buildings causes a large amount of carbon dioxide emissions, especially carbon emissions from rural buildings, which account for more than 20% of the country's total carbon emissions. Photovoltaic power is an inexhaustible, zero-carbon energy source, so using photovoltaic power to power rural buildings is an effective way to reduce carbon emissions related to building operation energy consumption. In some rural areas with abundant sunshine, a large number of farmers' households have installed photovoltaic power equipment for photovoltaic power generation.

[0003] Since photovoltaic power is volatile, the voltage and power of photovoltaic power change randomly and cannot be used directly to drive electrical equipment in buildings. Therefore, control and energy storage technologies are needed to maintain the voltage stability of the photovoltaic power system so that photovoltaic power can match the energy needs of the building. Therefore, in addition to installing photovoltaic power generation devices, household users also need to install additional control and energy storage equipment, which increases costs.

[0004] At the same time, if traditional individual PV users want to input the electricity generated by PV power equipment into the national grid to generate benefits, they generally need to go online directly through an inverter. More complex ones can also be connected to a microgrid, but the entire microgrid is centrally controlled by one or more controllers. The controller controls the operation of each inverter (that is, converting direct current into alternating current, because the electricity generated by photovoltaics is itself direct current) through a communication system to maintain voltage stability. Therefore, the traditional centralized control method requires a controller and a communication system, but the characteristics of rural PV equipment users are large in number and scattered in area. In this way, the use of traditional control methods in rural areas will greatly increase the cost of communications and controllers, reducing the economic efficiency of PV power systems in rural applications.

[0005] Therefore, how to provide a control method suitable for rural photovoltaic equipment users to facilitate them to realize their own photovoltaic power supply and external power output, and reduce their control costs, has become a technical problem that technical personnel in this field need to consider and solve. Summary of the invention

[0006] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is: how to provide a distributed photovoltaic power generation adaptive conversion control method that can reduce control costs and is suitable for rural photovoltaic equipment users to facilitate their own photovoltaic power supply and external power output. It is more conducive to the promotion and application of photovoltaic power equipment in rural areas and reduces the carbon emission indicators of rural building energy use.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions: A distributed photovoltaic power generation adaptive conversion control method is characterized in that a DC bus is used to establish an internal power grid between users of photovoltaic power generation devices, the output power of each photovoltaic power generation device is boosted and then connected to the DC bus, the DC bus is connected to the electrical equipment of each user and supplies power to it, and the DC bus voltage is detected at the same time. When the DC bus voltage is higher than 240V, the DC bus is controlled to output power to an external power supply, and when the DC bus voltage is lower than 220V, the external power supply is controlled to input power to the DC bus.

[0008] In this way, an internal power grid is established through the DC bus, and the internal power grid is used to centrally absorb the photovoltaic power of various decentralized users. When there is excess power, it is exported as a reserve power. When there is insufficient power, it is supplemented by external power. The DC bus voltage is maintained between 220V and 240V, and the internal power grid is stable, providing a stable power supply for the power equipment of various decentralized users. Therefore, this centralized control conversion method better reduces the control cost and is conducive to the promotion and application of photovoltaic power equipment in rural areas.

[0009] Furthermore, the external power source is a municipal power grid or an energy storage battery.

[0010] In this way, the photovoltaic power of dispersed users in rural areas can be better utilized to supply power to the municipal power grid. As another method, the external power source can also be an energy storage device, other external power grids of higher levels, a microgrid or a national power grid.

[0011] Furthermore, when the photovoltaic power generation device outputs power to the DC bus, the DC bus voltage signal is detected. When the DC bus voltage is higher than 240V, the photovoltaic power generation device is controlled to output a stable voltage. When the DC bus voltage is lower than 240V, the photovoltaic power generation device is tracked for the maximum power point. In this way, the photovoltaic power generation efficiency can be better improved.

[0012] Furthermore, the method is implemented by a distributed photovoltaic power generation and power consumption system, which includes photovoltaic power generation devices and power consumption equipment dispersed among various household users, and also includes a DC bus. Each photovoltaic power generation device is connected to the DC bus through a BOOST (power boost) boost circuit to form an internal power grid. The DC bus is connected to an external power supply through a BOOST-BUCK (boost-buck) bidirectional circuit. An electrical interface is provided on the DC bus, which is used to connect to each electrical consumption equipment.

[0013] Furthermore, the BOOST-BUCK bidirectional circuit includes a pair of external power connectors for connecting to an external power source, the external power connectors are sequentially connected in series with transistor A, inductor, diode B and resistor to form a loop, and also includes a capacitor, transistor B and diode A which are sequentially connected in parallel with the resistor from near to far, the diode B is located in the loop between the capacitor and transistor B, the inductor is located in the loop between diode A and transistor B, the transistor A is located in the loop between diode A and the external power connector, both ends of the resistor are connected to a DC bus, and the third ends of the transistor A and transistor B are commonly connected to one end of a voltage sensor and then connected to the DC bus.

[0014] The traditional control method for connecting the power of photovoltaic power generation devices to the external power grid is to use a centralized controller to connect the communication and inverter to control the stability of the system. In this application, each photovoltaic power generation device is first connected to the internal power grid of the DC, and then the internal power grid is uniformly connected to the external power supply (power grid or battery) by relying on the BOOST-BUCK bidirectional circuit structure. The principle of the above-mentioned BOOST-BUCK bidirectional circuit is to add a voltage sensor to the circuit of the DC converter to sense the voltage signal of the DC bus, and then input the difference between the voltage signal and the voltage setting value as a signal into the transistor of the circuit. The transistor reconfigures its own duty cycle according to the difference, and the duty cycle corresponds to the output power of the system. Among them, the boost of the internal power grid is achieved by controlling transistor B, and the buck is achieved by controlling transistor A. There are different corresponding functional relationships between different voltage differences and output powers. Within a certain range (dead zone), small fluctuations in voltage will not cause the action of the converter, and the internal power grid will not charge or draw power from the external power supply. When it exceeds a certain range, the transistor controls the output power according to the voltage difference. The two are basically linear. The greater the voltage deviation, the greater the power, which is convenient for quickly stabilizing the voltage signal within a predetermined range. The slope of the change (related to the size of the duty cycle) and the range of the dead zone are adjustable. In this way, the above-mentioned BOOST-BUCK bidirectional circuit structure can sense the voltage signal at its own position to change the operating condition without the need for additional communication and controller. This greatly reduces the cost of the equipment.

[0015] The above-mentioned BOOST-BUCK bidirectional circuit structure can provide power from the internal power grid to the external power supply or obtain power from the external power supply. The functions of each component in the circuit structure are: inductor (storing power, adjusting voltage), diode, capacitor (storing power, adjusting voltage), resistor (resistance determines the dead zone range), transistor (changing the output power by changing the duty cycle) and voltage sensor (sensing the DC bus voltage, and adjusting the duty cycle of the transistor according to the difference between the DC bus voltage and the set voltage, thereby changing the output power). The output end of the circuit structure is directly connected to the external power supply connector. In this way, after being set in advance, the BOOST-BUCK bidirectional circuit can sense the DC bus voltage signal to automatically change its own operating mode. It can be set that when the DC bus voltage of the internal power grid is higher than 240V, the BOOST-BUCK bidirectional circuit transmits the power of the DC bus to the external power supply; when the DC bus voltage of the internal power grid is lower than 220V, the BOOST-BUCK bidirectional circuit transmits the power of the external power supply to the DC bus; when the DC bus voltage is between 220V-240V, the BOOST-BUCK bidirectional circuit stops working.

[0016] Furthermore, the BOOST boost circuit includes a pair of photovoltaic connectors for connecting to a photovoltaic power generation device, the photovoltaic connectors are connected in series with a boost inductor (storing power, regulating voltage), a boost diode and a boost resistor to form a loop, a boost capacitor (storing power, regulating voltage) is arranged in parallel between the boost resistor and the photovoltaic connector, a boost transistor (changing the circuit operation mode by changing the duty cycle, i.e., constant voltage mode or maximum power point tracking mode) is arranged in parallel between the boost capacitor and the photovoltaic connector, the boost diode is located between the boost transistor and the boost capacitor, and the boost inductor is located between the boost transistor and the photovoltaic connector; both ends of the boost resistor are connected to a DC bus, and the third end of the boost transistor is connected to a boost voltage sensor (sensing the DC bus voltage, and adjusting the duty cycle of the transistor according to the difference between the DC bus voltage and the set voltage, thereby changing the output power) and then connected to the DC bus.

[0017] In this way, the BOOST boost circuit can sense the DC bus voltage signal to automatically change its own operating mode. It can be set that when the DC bus voltage is higher than 240V, the BOOST boost circuit will operate in constant voltage mode to keep the photovoltaic power output voltage stable; when the DC bus voltage is lower than 240V, the BOOST boost circuit will operate in maximum power point tracking mode to improve photovoltaic power generation efficiency. During implementation, the BOOST boost circuit and the BOOST-BUCK bidirectional circuit both sense the voltage signal value and then respond by changing the circuit duty cycle to achieve control.

[0018] Furthermore, the interactive power of the external power source connected to the BOOST-BUCK bidirectional circuit is ≥ the maximum output power (i.e., rated output power) of the DC bus power interface. In this way, it can be ensured that the operation of the power equipment can be supplied by the external power source when there is a lack of photovoltaic power on rainy days or at night.

[0019] Furthermore, the parallel voltage of the photovoltaic power generation device connected to the BOOST boost circuit is not higher than 250V, which prevents the fluctuation of photovoltaic power from damaging the circuit equipment and is conducive to maintaining a relatively stable bus voltage; the result of multiplying the capacity of the photovoltaic power generation device by the local full power generation hours is greater than the energy storage capacity of the external power supply connected to the BOOST-BUCK bidirectional circuit. In this way, it can be ensured that the configuration of the external power supply energy storage capacity meets the needs of the electrical equipment, and that the photovoltaic power can meet the charging needs of the energy storage.

[0020] Furthermore, the capacity of the external power source connected to the BOOST-BUCK bidirectional circuit can meet the rated power output of the power interface of the DC bus for more than 5 hours. Similarly, it can ensure the operation of the power equipment relying on the external power supply when there is a lack of photovoltaic power on rainy days or at night.

[0021] In summary, the present invention solves the problems in the related art that the rural photovoltaic power system is not economically efficient due to the high control cost of the distributed photovoltaic power system, and the uncertainty of photovoltaic power generation is not improved, making it difficult to ensure stable voltage and power output, and reducing the applicability and stability of the photovoltaic power system in rural building applications. Therefore, it is suitable for rural photovoltaic equipment users to facilitate their own photovoltaic power supply and external power output, which can reduce control costs and reduce carbon emission indicators of rural building energy use. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the distributed photovoltaic power generation system of the present invention.

[0023] Figure 2 It is a schematic diagram of the structure of the BOOST-BUCK bidirectional circuit in the present invention.

[0024] Figure 3 The figure is a schematic diagram of the working process steps of the BOOST boost circuit and the BOOST-BUCK bidirectional circuit in the present invention.

[0025] Figure 4 It is a structural schematic diagram of the BOOST boost circuit in the present invention. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with specific implementation modes.

[0027] Best practice: A distributed photovoltaic power generation adaptive conversion control method is characterized in that a DC bus is used to establish an internal power grid between users of photovoltaic power generation devices, the output power of each photovoltaic power generation device is boosted and connected to the DC bus, the DC bus is connected to the electrical equipment of each user and supplies power to it, and the DC bus voltage is detected at the same time. When the DC bus voltage is higher than 240V, the DC bus is controlled to output power to an external power supply, and when the DC bus voltage is lower than 220V, the external power supply is controlled to input power to the DC bus.

[0028] In this way, an internal power grid is established through the DC bus, and the internal power grid is used to centrally absorb the photovoltaic power of various decentralized users. When there is excess power, it is exported as a reserve power. When there is insufficient power, it is supplemented by external power. The DC bus voltage is maintained between 220V and 240V, and the internal power grid is stable, providing a stable power supply for the power equipment of various decentralized users. Therefore, this centralized control conversion method better reduces the control cost and is conducive to the promotion and application of photovoltaic power equipment in rural areas.

[0029] In this embodiment, the external power source is a municipal power grid.

[0030] In this way, the photovoltaic power of dispersed users in rural areas can be better utilized to supply power to the municipal power grid. As another method, the external power source can also be an energy storage device, other external power grids of higher levels, a microgrid or a national power grid.

[0031] During implementation, when the photovoltaic power generation device outputs power to the DC bus, the DC bus voltage signal is detected. When the DC bus voltage is higher than 240V, the photovoltaic power generation device is controlled to output a stable voltage. When the DC bus voltage is lower than 240V, the photovoltaic power generation device is tracked for the maximum power point. In this way, the efficiency of photovoltaic power generation can be better improved.

[0032] In this embodiment, the method is implemented by a distributed photovoltaic power generation system, see Figure 1-4 The distributed photovoltaic power generation and power consumption system includes photovoltaic power generation devices 1 and power consumption equipment 2 distributed among household users, and also includes a DC bus 3. Each photovoltaic power generation device is connected to the DC bus 3 through a BOOST (power boost) boost circuit 4 to form an internal power grid. The DC bus 3 is connected to an external power supply 6 through a BOOST-BUCK (boost-buck) bidirectional circuit 5. A power consumption interface is provided on the DC bus, and the power consumption interface is used to connect to each power consumption equipment 2.

[0033] Among them, the BOOST-BUCK bidirectional circuit, see Figure 2, including a pair of external power connectors 7 for connecting to an external power source, the external power connector 7 is sequentially connected in series with a transistor A8, an inductor 14, a diode B9 and a resistor 10 to form a loop, and also includes a capacitor 11, a transistor B12 and a diode A13 which are sequentially connected in parallel with the resistor from near to far, the diode B9 is located in the loop between the capacitor 11 and the transistor B12, the inductor 14 is located in the loop between the diode A13 and the transistor B12, the transistor A8 is located in the loop between the diode A13 and the external power connector 7, the two ends of the resistor 10 are connected to a DC bus 3, and the third ends of the transistor A and the transistor B are commonly connected to one end of a voltage sensor 15 and then connected to the DC bus 3.

[0034] The traditional control method for connecting the power of photovoltaic power generation devices to the external power grid is to use a centralized controller to connect the communication and inverter to control the stability of the system. In this application, each photovoltaic power generation device is first connected to the internal power grid of the DC, and then the internal power grid is uniformly connected to the external power supply (power grid or battery) by relying on the BOOST-BUCK bidirectional circuit structure. The principle of the above-mentioned BOOST-BUCK bidirectional circuit is to add a voltage sensor to the circuit of the DC converter to sense the voltage signal of the DC bus, and then input the difference between the voltage signal and the voltage setting value as a signal into the transistor of the circuit. The transistor reconfigures its own duty cycle according to the difference, and the duty cycle corresponds to the output power of the system. Among them, the boost of the internal power grid is achieved by controlling transistor B, and the buck is achieved by controlling transistor A. There are different corresponding functional relationships between different voltage differences and output powers. Within a certain range (dead zone), small fluctuations in voltage will not cause the action of the converter, and the internal power grid will not charge or draw power from the external power supply. When it exceeds a certain range, the transistor controls the output power according to the voltage difference. The two are basically linear. The greater the voltage deviation, the greater the power, which is convenient for quickly stabilizing the voltage signal within a predetermined range. The slope of the change (related to the size of the duty cycle) and the range of the dead zone are adjustable. In this way, the above-mentioned BOOST-BUCK bidirectional circuit structure can sense the voltage signal at its own position to change the operating condition without the need for additional communication and controller. This greatly reduces the cost of the equipment.

[0035] The above-mentioned BOOST-BUCK bidirectional circuit structure can provide power from the internal power grid to the external power supply or obtain power from the external power supply. The functions of the various components in the circuit structure are: inductor (storing power, regulating voltage), diode, capacitor (storing power, regulating voltage), resistor (resistance determines the dead zone range), transistor (changing the output power by changing the duty cycle) and voltage sensor (sense the DC bus voltage, and adjust the duty cycle of the transistor according to the difference between the DC bus voltage and the set voltage, thereby changing the output power). The output end of the circuit structure is directly connected to the external power supply connector. In this way, after being set in advance, the BOOST-BUCK bidirectional circuit can sense the DC bus voltage signal to automatically change its own operating mode (see Figure 3 ), it can be set that when the DC bus voltage of the internal power grid is higher than 240V, the BOOST-BUCK bidirectional circuit transmits the power of the DC bus to the external power supply; when the DC bus voltage of the internal power grid is lower than 220V, the BOOST-BUCK bidirectional circuit transmits the power of the external power supply to the DC bus; when the DC bus voltage is between 220V-240V, the BOOST-BUCK bidirectional circuit stops working.

[0036] Among them, the BOOST boost circuit, see Figure 4 , comprising a pair of photovoltaic connectors 16 for connecting to a photovoltaic power generation device, the photovoltaic connector 16 is connected in series with a boost inductor 17 (storing power and regulating voltage), a boost diode 18 and a boost resistor 19 in sequence to form a loop, a boost capacitor 20 (storing power and regulating voltage) is arranged in parallel between the boost resistor 19 and the photovoltaic connector 16, a boost transistor 21 (changing the circuit operation mode by changing the duty cycle, i.e., constant voltage mode or maximum power point tracking mode) is arranged in parallel between the boost capacitor 20 and the photovoltaic connector, the boost diode 18 is located between the boost transistor 21 and the boost capacitor 20, the boost inductor 17 is located between the boost transistor 21 and the photovoltaic connector 16; both ends of the boost resistor 19 are connected to a DC bus 3, the third end of the boost transistor 21 is connected to a boost voltage sensor 22 (senses the DC bus voltage, and adjusts the duty cycle of the transistor according to the difference between the DC bus voltage and the set voltage, thereby changing the output power) and then connected to the DC bus 3.

[0037] In this way, the BOOST boost circuit can sense the DC bus voltage signal to automatically change its own operating mode (see Figure 3), it can be set that when the DC bus voltage is higher than 240V, the BOOST boost circuit will run in constant voltage mode to keep the photovoltaic power output voltage stable; when the DC bus voltage is lower than 240V, the BOOST boost circuit will run in maximum power point tracking mode to improve photovoltaic power generation efficiency. In implementation, the BOOST boost circuit and the BOOST-BUCK bidirectional circuit both sense the voltage signal value and then respond to it by changing the circuit duty cycle to achieve control.

[0038] During implementation, the interactive power of the external power source connected to the BOOST-BUCK bidirectional circuit is ≥ the maximum output power (i.e., rated output power) of the DC bus power interface. In this way, it can be ensured that the operation of the power equipment is supplied by the external power source when there is a lack of photovoltaic power on rainy days or at night.

[0039] During implementation, the parallel voltage of the photovoltaic power generation device connected to the BOOST boost circuit is not higher than 250V, which prevents the fluctuation of photovoltaic power from damaging the circuit equipment and is conducive to maintaining a relatively stable bus voltage; the result of multiplying the capacity of the photovoltaic power generation device by the local full power generation hours is greater than the energy storage capacity of the external power supply connected to the BOOST-BUCK bidirectional circuit. In this way, it can be ensured that the configuration of the external power supply energy storage capacity meets the needs of the power-consuming equipment, and that the photovoltaic power can meet the charging needs of the energy storage.

[0040] When implemented, the capacity of the external power supply connected to the BOOST-BUCK bidirectional circuit can meet the rated power output of the power interface of the DC bus for more than 5 hours. Similarly, it can ensure the operation of the power equipment relying on the external power supply when there is a lack of photovoltaic power on rainy days or at night.

[0041] During implementation, the DC bus voltage and the output voltage of its interface are maintained between 220V-240V. During implementation, the system uses all DC power, and the value of the DC voltage is the only control signal of the power system. Therefore, the present invention also has the following characteristics. 1 The present invention uses a DC system, and there are very few parameters that need to be controlled, and there is no regulation of the phase and frequency of the AC power. 2 The scheme of the present invention does not have a controller and a communication system. It makes changes in the BOOST circuit in the DC converter so that it can respond to changes in the voltage signal and change the operating mode. In this way, the control of the microgrid changes from centralized to decentralized. The prior art usually adopts centralized control of the controller, which is applied to decentralized photovoltaic systems, such as rural areas, and the cost will be very high. The present invention can achieve a stable bus DC voltage output by the device based on the real-time voltage signal value by automatically switching the operating mode of different devices, saving the cost of the controller and the communication system, improving the stability and economy of the distributed photovoltaic power system, and being more practical.

[0042] The working principle of the embodiments of the present application is described in detail below with reference to some specific embodiments.

[0043] For example, on a clear day with sufficient sunlight, the photovoltaic power generation device generates a large power, and the electrical load of the electrical equipment connected to the power interface is very large. The BOOST boost circuit keeps the photovoltaic power generation device outputting at the maximum power point; if the voltage of the DC bus is higher than 240V, it means that the power supply of the photovoltaic power generation device is greater than the demand of the electrical equipment at this moment, then the BOOST-BUCK bidirectional circuit starts to work and transmits power to the external power supply. The BOOST boost circuit changes the operating mode to the constant voltage mode to ensure that the DC bus voltage is within the preset range; in the evening, the power supply of the photovoltaic power generation device is less than the demand of the electrical equipment. If the voltage of the DC bus is lower than 220V, the BOOST boost circuit keeps the photovoltaic output at the maximum power point, and the BOOST-BUCK bidirectional circuit obtains power from the external power supply to meet the needs of the electrical equipment and maintains the DC bus between 220V-240V.

[0044] For example, on rainy days or at night, there is no electricity from the photovoltaic power generation device, but the power interface is still running with power-consuming equipment. The BOOST-BUCK bidirectional circuit senses that the bus voltage has dropped below 220V, and draws power from the external power supply to the DC bus to maintain the DC bus voltage within the preset range.

[0045] Therefore, according to the scheme of the present application, by automatically switching the operation modes of different devices based on real-time voltage signals, a stable voltage output can be achieved, which saves the control cost of the rural distributed photovoltaic power system, improves the reliability of the photovoltaic power system, and makes it more practical. Thus, the problem in the related art that the cost of the rural distributed photovoltaic power system controller and communication system is high, resulting in insufficient economic efficiency of the rural photovoltaic power system, and the uncertainty of photovoltaic power generation is not improved, making it difficult to ensure stable voltage and power output, and reducing the applicability and stability of the rural photovoltaic power system in rural applications.

Claims

1. A distributed photovoltaic power generation adaptive conversion control method, characterized in that: A DC bus is used to establish an internal power grid between users of photovoltaic power generation devices. The output power of each photovoltaic power generation device is boosted and connected to the DC bus. The DC bus is connected to the electrical equipment of each user and supplies power to them. At the same time, the DC bus voltage is detected. When the DC bus voltage is higher than 240V, the DC bus is controlled to output power to the external power supply. When the DC bus voltage is lower than 220V, the external power supply is controlled to input power to the DC bus.

2. The distributed photovoltaic power generation adaptive conversion control method according to claim 1, characterized in that: The external power source is a municipal power grid or an energy storage battery.

3. The distributed photovoltaic power generation adaptive conversion control method according to claim 1, characterized in that: When the photovoltaic power generation device outputs power to the DC bus, the DC bus voltage signal is detected. When the DC bus voltage is higher than 240V, the photovoltaic power generation device is controlled to output a stable voltage. When the DC bus voltage is lower than 240V, the maximum power point of the photovoltaic power generation device is tracked.

4. The distributed photovoltaic power generation adaptive conversion control method according to claim 1, characterized in that: The method is implemented by a distributed photovoltaic power generation and power consumption system, which includes photovoltaic power generation devices and power consumption equipment dispersed among household users, and also includes a DC bus. Each photovoltaic power generation device is connected to the DC bus through a BOOST boost circuit to form an internal power grid. The DC bus is connected to an external power supply through a BOOST-BUCK bidirectional circuit. A power consumption interface is provided on the DC bus, which is used to connect to each power consumption equipment.

5. The distributed photovoltaic power generation adaptive conversion control method according to claim 4, characterized in that: The BOOST-BUCK bidirectional circuit includes a pair of external power connectors for connecting to an external power source, the external power connectors are sequentially connected in series with a transistor A, an inductor, a diode B and a resistor to form a loop, and also includes a capacitor, a transistor B and a diode A which are sequentially connected in parallel with the resistor from near to far, the diode B is located in the loop between the capacitor and the transistor B, the inductor is located in the loop between the diode A and the transistor B, the transistor A is located in the loop between the diode A and the external power connector, both ends of the resistor are connected to a DC bus, and the third ends of the transistor A and the transistor B are commonly connected to one end of a voltage sensor and then connected to the DC bus.

6. The distributed photovoltaic power generation adaptive conversion control method according to claim 4, characterized in that: The BOOST boost circuit includes a pair of photovoltaic connectors for connecting to a photovoltaic power generation device. The photovoltaic connectors are connected in series with a boost inductor, a boost diode and a boost resistor to form a loop. A boost capacitor is arranged in parallel between the boost resistor and the photovoltaic connector. A boost transistor is arranged in parallel between the boost capacitor and the photovoltaic connector. The boost diode is located between the boost transistor and the boost capacitor. The boost inductor is located between the boost transistor and the photovoltaic connector. Both ends of the boost resistor are connected to a DC bus. The third end of the boost transistor is connected to a boost voltage sensor and then to the DC bus.

7. The distributed photovoltaic power generation adaptive conversion control method according to claim 4, characterized in that: The interactive power of the external power supply connected to the BOOST-BUCK bidirectional circuit is ≥ the maximum output power of the DC bus power interface.

8. The distributed photovoltaic power generation adaptive conversion control method according to claim 4, characterized in that: The parallel voltage of the photovoltaic power generation device connected to the BOOST boost circuit is not higher than 250V, and the result of multiplying the capacity of the photovoltaic power generation device by the local full power generation hours is greater than the energy storage capacity of the external power supply connected to the BOOST-BUCK bidirectional circuit.

9. The distributed photovoltaic power generation adaptive conversion control method according to claim 4, characterized in that: The capacity of the external power supply connected to the BOOST-BUCK bidirectional circuit can meet the rated power output of the power interface of the DC bus for more than 5 hours.

10. The distributed photovoltaic power generation adaptive conversion control method according to claim 4, characterized in that: The DC bus voltage and the output voltage of its interface are maintained between 220V and 240V.

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