Low-cost photovoltaic networking large-voltage power supply control system and method

Abstract

The invention discloses a low-cost photovoltaic networking large-voltage power supply control system and method, and belongs to the technical field of large-voltage power supply, and the method comprises the following steps: all photovoltaic power generation devices are connected to the system, the photovoltaic number is calculated, the minimum photovoltaic number required by each group is calculated, the output end of each photovoltaic power generation device is provided with a rectification and voltage stabilization device, and the rectification and voltage stabilization devices are connected to the system; the method comprises the following steps: dividing photovoltaic power generation groups, connecting the output ends of rectifying and voltage-stabilizing devices in the same photovoltaic power generation group in series, electrically connecting the output ends of the rectifying and voltage-stabilizing devices with inverters, electrically connecting the output ends of the inverters with transformers, connecting the output ends of the transformers in series, and adjusting the inverters and the transformers according to the voltage value of a load end and the number of the inverters. The small transformers are connected in series, the same voltage as that of the large transformer is output, and the cost is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of high-voltage power supply, and in particular to a low-cost photovoltaic grid-connected high-voltage power supply control system and method. Background Technology

[0002] Photovoltaic power generation technology is becoming increasingly mature and can now provide a considerable amount of electricity daily. While the voltage of photovoltaic power generated can be stabilized within a certain range after rectification and voltage regulation, it cannot directly reach high voltage levels. When high voltage power supply is required, the electricity generated by photovoltaic power typically needs to be stepped up by a large transformer.

[0003] The existing technical solutions mentioned above have the following drawbacks: large transformers are relatively expensive. If the photovoltaic scale is large, a large number of large transformers will be needed, and the power supply cost will be very high. Summary of the Invention

[0004] To reduce power supply costs, this application provides a low-cost photovoltaic grid-connected high-voltage power supply control system and method.

[0005] On the one hand, the low-cost photovoltaic grid-connected high-voltage power supply control method provided in this application adopts the following technical solution: A low-cost photovoltaic grid-connected high-voltage power supply control method includes the following steps: Preset load voltage value; Connect all photovoltaic power generation devices to the system and calculate the number of photovoltaic units; Collect the voltage value output by each photovoltaic power generation device connected to the system within a set time period, calculate the average voltage value output by each photovoltaic power generation device, and then calculate the average voltage value output by all photovoltaic power generation devices. Calculate the minimum number of photovoltaic units required for each group based on the load voltage and the average output voltage of the photovoltaic power generation equipment. Each photovoltaic power generation device is equipped with a rectifier and voltage regulator at its output terminal to output DC power; Photovoltaic power generation groups are divided according to the DC power output of the rectifier and voltage regulator and the minimum number of photovoltaic cells required for each group, and the output terminals of the rectifier and voltage regulator in the same group are connected in series. The DC power output from the rectifier and voltage regulator of the same photovoltaic power generation group is shunted and then input into the same number of inverters as the number of photovoltaic devices in the photovoltaic power generation group. The output terminals of the inverters are electrically connected to the transformers, and the output terminals of the transformers are connected in series. The inverters and transformers are adjusted according to the load voltage value and the number of inverters. DC power is output as AC power by each inverter, and the AC power is stepped up by a transformer and then transmitted to the load.

[0006] By adopting the above scheme, the system automatically divides the photovoltaic system into multiple photovoltaic power generation groups according to the voltage requirements of the load. The current generated by the photovoltaic power generation equipment in the same group is combined and then split between the inverters to obtain the same voltage value. After being adjusted by the transformer, it is combined into AC power that meets the voltage requirements of the load. This ensures that the load can obtain the required high-voltage AC power, and also effectively reduces the power supply cost by using multiple small transformers instead of large transformers.

[0007] Preferably, the following steps are also included: Calculate the average power generation of each photovoltaic power generation device based on the load voltage value and the number of photovoltaic power generation devices in each photovoltaic power generation group; All photovoltaic power generation units are divided into multiple regional groups. Each regional group uses one of the photovoltaic power generation units as a backup group. The output terminal of each transformer in the backup group is electrically connected to the output terminal of one transformer in other photovoltaic power generation units. The output terminal of each photovoltaic power generation unit is electrically connected to the output terminal of a transformer in the backup group. A normally open switch is connected in series at the connection point between the output terminal of each photovoltaic power generation unit and the transformer in the backup group. Detect the voltage at the output of each rectifier and voltage regulator and the total voltage output by each photovoltaic power generation unit to the load. When the voltage at the output terminal of any rectifier and voltage regulator is lower than the average power generation, and the total voltage output from the photovoltaic power generation group to the load terminal of the rectifier and voltage regulator is lower than the load terminal voltage value, the rectifier and voltage regulator is disconnected, and the normally open switch between the transformer corresponding to the rectifier and voltage regulator and the transformer of the standby group that is electrically connected is closed.

[0008] By adopting the above scheme, multiple photovoltaic power generation units are divided into a large regional group, and one photovoltaic power generation unit is selected as a standby group. The AC power output of the standby group can be used for equipment with low voltage requirements or that can be stopped at any time. When the DC power output of any photovoltaic power generation equipment decreases below the average expected power generation, the system will suspend the operation of the line where the photovoltaic power generation equipment is located, and disconnect the corresponding line from the standby group and connect it to the photovoltaic power generation unit that lacks photovoltaic power generation equipment, so as to ensure that the final output AC voltage value can reach the voltage value required by the load.

[0009] Preferably, the following steps are also included: When the voltage at the output terminal of any rectifier and voltage regulator is lower than the average power generation, the voltage output of other transformers in the photovoltaic power generation group where the rectifier and voltage regulator is located is increased based on the voltage difference between the output voltage of the rectifier and voltage regulator and the average power generation, so that the total voltage output by the photovoltaic power generation group where the rectifier and voltage regulator is located to the load terminal is equal to the load terminal voltage value, and the control of the normally open switch is suspended. If the voltage output of other transformers in the photovoltaic power generation unit where the rectifier and voltage regulator is located cannot reach the increased voltage, then the voltage increase is canceled and the control of the normally open switch is restored.

[0010] By adopting the above scheme, before suspending the operation of the line where the photovoltaic power generation equipment is located, the system will first try to compensate with the power output of other photovoltaic power generation equipment. If the compensation cannot be completed, the operation of the line where the photovoltaic power generation equipment is located will be suspended and the backup group will be activated.

[0011] Preferably, the following steps are also included: When the sum of the voltage difference between the output voltage of the transformer in the large area group and the voltage of the average expected power generation is greater than the voltage value at the load end, an alarm is issued and the connection between all photovoltaic power generation groups with transformers whose output voltage is lower than the average expected power generation and the load end is suspended, and an alarm is issued.

[0012] By adopting the above scheme, if the power output of the entire area's large-scale photovoltaic power generation units drops significantly, causing the backup units to be insufficient to compensate for the power loss of other photovoltaic power generation units, then the photovoltaic power generation units with the huge power output drop will be abandoned, causing them to stop working, and an alarm will be issued to remind users.

[0013] Preferably, the following steps are also included: A preset voltage variation limit is set, which is calculated based on the average output power of the current photovoltaic power generation equipment. When a new load-side voltage value is received that overrides the original load-side voltage value, a new average power generation should be calculated based on the new load-side voltage value and the number of photovoltaic cells in the current photovoltaic power generation unit. Calculate the difference between the new average expected power generation and the current average expected power generation, and determine whether the difference is greater than the voltage change limit; If the difference is less than the voltage change limit, the photovoltaic power generation equipment is disconnected and the rectifier, voltage regulator, inverter or transformer is adjusted according to the new average power generation. Then the photovoltaic power generation equipment circuit is controlled so that the output voltage of the photovoltaic power generation unit reaches the new average power generation. If the difference exceeds the voltage variation limit, the minimum number of photovoltaic units required for each group will be recalculated based on the new load voltage and the average output voltage of the photovoltaic power generation equipment.

[0014] By adopting the above scheme, if the voltage required by the load changes after switching to a new load, the system can first determine whether the voltage change can be compensated by adjusting the hardware parameters. If the original photovoltaic power generation unit cannot meet the voltage requirements of the new load, the circuit and system can be reconfigured.

[0015] On the other hand, the low-cost photovoltaic grid-connected high-voltage power supply control system provided in this application adopts the following technical solution: A low-cost photovoltaic grid-connected high-voltage power supply control system includes multiple photovoltaic power generation devices and a photovoltaic control system. Each photovoltaic power generation device is electrically connected to a rectifier and voltage regulator. The photovoltaic control system includes a data acquisition module, an automatic grouping module, and a power supply control module. The data acquisition module collects the DC voltage values ​​output by the photovoltaic power generation equipment and the DC voltage values ​​output by the rectifier and voltage regulator equipment, and transmits the DC voltage values ​​output by the photovoltaic power generation equipment and the DC voltage values ​​output by the rectifier and voltage regulator equipment to the automatic grouping module. The automatic grouping module presets a voltage change limit. The automatic grouping module intercepts the voltage value output by each photovoltaic power generation device within a set time, calculates the average voltage value output by each photovoltaic power generation device, and then calculates the average voltage value output by all photovoltaic power generation devices. Based on the load end voltage value and the average voltage value output by the photovoltaic power generation devices, it calculates the minimum number of photovoltaics required for each group. Based on the DC power output by the rectifier and voltage regulator and the minimum number of photovoltaics required for each group, the photovoltaic power generation groups are divided. The output terminals of the rectifier and voltage regulator within the same photovoltaic power generation group are connected in series, and the information of the same photovoltaic power generation group is transmitted to the power supply control module. The power supply control module, based on information from the photovoltaic power generation group in the same group, shunts the DC power output from the rectifier and voltage regulator of the same photovoltaic power generation group before inputting it into the same number of inverters as the number of photovoltaic devices in the photovoltaic power generation group. The output terminals of the inverters are electrically connected to the transformers, and the output terminals of the transformers are connected in series. The inverters and transformers are adjusted according to the load voltage value and the number of inverters. The DC power outputs AC power through each inverter, and the AC power is stepped up by the transformer and transmitted to the load.

[0016] By adopting the above scheme, the system automatically divides the photovoltaic system into multiple photovoltaic power generation groups according to the voltage requirements of the load. The current generated by the photovoltaic power generation equipment in the same group is combined and then split between the inverters to obtain the same voltage value. After being adjusted by the transformer, it is combined into AC power that meets the voltage requirements of the load. This ensures that the load can obtain the required high-voltage AC power, and also effectively reduces the power supply cost by using multiple small transformers instead of large transformers.

[0017] Preferably, the photovoltaic control system also includes a power shortage compensation module; The automatic grouping module calculates the average power generation of each photovoltaic power generation device based on the load voltage value and the number of photovoltaic power generation devices in each photovoltaic power generation group, and transmits the average power generation to the power shortage compensation module. The data acquisition module collects the total voltage output from the photovoltaic power generation unit to the load end; The power shortage compensation module divides all photovoltaic power generation units into multiple regional groups. Each regional group designates one group of photovoltaic power generation units as a backup group. The output terminal of each transformer in the backup group is electrically connected to the output terminal of one transformer in another photovoltaic power generation unit. The output terminal of each photovoltaic power generation unit's transformer is electrically connected to the output terminal of a transformer in the backup group. A normally open switch is connected in series at the connection point between the output terminal of each photovoltaic power generation unit's transformer and the transformer in the backup group. The module collects the voltage at the output terminal of each rectifier and voltage regulator and the total voltage output by each photovoltaic power generation unit to the load. When the voltage at the output terminal of any rectifier and voltage regulator is lower than the average expected power generation, and the total voltage output by the photovoltaic power generation unit to the load is lower than the load voltage, the rectifier and voltage regulator is disconnected, and the normally open switch between the transformer corresponding to the rectifier and voltage regulator and the transformer in the backup group is closed.

[0018] By adopting the above scheme, multiple photovoltaic power generation units are divided into a large regional group, and one photovoltaic power generation unit is selected as a standby group. The AC power output of the standby group can be used for equipment with low voltage requirements or that can be stopped at any time. When the DC power output of any photovoltaic power generation equipment decreases below the average expected power generation, the system will suspend the operation of the line where the photovoltaic power generation equipment is located, and disconnect the corresponding line from the standby group and connect it to the photovoltaic power generation unit that lacks photovoltaic power generation equipment, so as to ensure that the final output AC voltage value can reach the voltage value required by the load.

[0019] Preferably, when the voltage at the output terminal of any rectifier and voltage regulator is lower than the average expected power generation, the power shortage compensation module first increases the output voltage of other transformers in the photovoltaic power generation group where the rectifier and voltage regulator is located, based on the voltage difference between the output voltage of the rectifier and voltage regulator and the average expected power generation, so that the total voltage output by the photovoltaic power generation group where the rectifier and voltage regulator is located to the load terminal is equal to the load terminal voltage value, and then suspends the control of the normally open switch. If the output voltage of other transformers in the photovoltaic power generation group where the rectifier and voltage regulator is located cannot reach the increased voltage, then the voltage increase is canceled and the control of the normally open switch is resumed.

[0020] By adopting the above scheme, before suspending the operation of the line where the photovoltaic power generation equipment is located, the system will first try to compensate with the power output of other photovoltaic power generation equipment. If the compensation cannot be completed, the operation of the line where the photovoltaic power generation equipment is located will be suspended and the backup group will be activated.

[0021] Preferably, the power shortage compensation module calculates that when the sum of the voltage difference between the output voltage of the transformer in the large area group and the voltage of the average expected power generation is greater than the voltage value of the load end, it issues an alarm and suspends the connection between all photovoltaic power generation groups with transformers whose output voltage is lower than the average expected power generation and the load end, and issues an alarm.

[0022] By adopting the above scheme, if the power output of the entire area's large-scale photovoltaic power generation units drops significantly, causing the backup units to be insufficient to compensate for the power loss of other photovoltaic power generation units, then the photovoltaic power generation units with the huge power output drop will be abandoned, causing them to stop working, and an alarm will be issued to remind users.

[0023] Preferably, the automatic grouping module presets a voltage change limit, which is calculated based on the average output power of the current photovoltaic power generation equipment. When a new load-end voltage value is received that covers the original load-end voltage value, a new average expected power generation is calculated based on the new load-end voltage value and the number of photovoltaic cells in the current photovoltaic power generation group. The difference between the new average expected power generation and the current average expected power generation is calculated, and it is determined whether the difference is greater than the voltage change limit. If the difference is less than the voltage change limit, the photovoltaic power generation equipment is controlled to disconnect, and the rectifier and voltage regulator, inverter, or transformer is adjusted according to the new average expected power generation. Then, the photovoltaic power generation equipment circuit is controlled so that the output voltage of the photovoltaic power generation group reaches the new average expected power generation. If the difference is greater than the voltage change limit, the minimum number of photovoltaic cells required for each group is recalculated based on the new load-end voltage value and the average output voltage value of the photovoltaic power generation equipment.

[0024] By adopting the above scheme, if the voltage required by the load changes after switching to a new load, the system can first determine whether the voltage change can be compensated by adjusting the hardware parameters. If the original photovoltaic power generation unit cannot meet the voltage requirements of the new load, the circuit and system can be reconfigured.

[0025] In summary, the present invention has the following beneficial effects: Based on the voltage requirements of the load, the system automatically divides the photovoltaic system into multiple photovoltaic power generation groups, which ensures that the load can obtain the required high-voltage AC power, and also effectively reduces the power supply cost by using multiple small transformers instead of large transformers. Attached Figure Description

[0026] Figure 1 This is an overall system block diagram of Embodiment 1 of this application.

[0027] Figure 2 This is a circuit diagram of Embodiment 1 of this application.

[0028] Explanation of reference numerals in the attached figures: 1. Photovoltaic power generation equipment; 2. Rectifier and voltage regulator equipment; 3. Inverter; 4. Transformer; 5. Load end; 6. Photovoltaic control system; 61. Data acquisition module; 62. Automatic grouping module; 63. Power supply control module; 64. Power shortage compensation module; 641. Normally open switch. Detailed Implementation

[0029] The following is in conjunction with the appendix Figure 1-2 This application will be described in further detail.

[0030] Example 1: This application discloses a low-cost photovoltaic grid-connected high-voltage power supply control system, such as... Figure 1 and Figure 2 As shown, the system includes a photovoltaic control system 6 and multiple photovoltaic power generation devices 1, each of which is electrically connected to a rectifier and voltage regulator 2. The photovoltaic control system 6 includes a data acquisition module 61, an automatic grouping module 62, a power supply control module 63, and a power shortage compensation module 64.

[0031] like Figure 1 and Figure 2 As shown, the data acquisition module 61 acquires the DC voltage value output by the photovoltaic power generation device 1, the DC voltage value output by the rectifier and voltage regulator device 2, and the total voltage output by the photovoltaic power generation group to the load terminal 5, and transmits the DC voltage value output by the photovoltaic power generation device 1 and the DC voltage value output by the rectifier and voltage regulator device 2 to the automatic grouping module 62.

[0032] like Figure 1 and Figure 2 As shown, the automatic grouping module 62 presets a voltage variation limit. It intercepts the voltage output of each photovoltaic power generation device 1 within a set time period, calculates the average voltage output of each photovoltaic power generation device 1, and then calculates the average voltage output of all photovoltaic power generation devices 1. Based on the load terminal voltage 5 and the average voltage output of the photovoltaic power generation devices 1, it calculates the minimum number of photovoltaic units required for each group. Based on the DC power output of the rectifier and voltage regulator 2 and the minimum number of photovoltaic units required for each group, it divides the photovoltaic power generation into groups. The output terminals of the rectifier and voltage regulator 2 within the same photovoltaic power generation group are connected in series, and the information of the photovoltaic power generation groups is transmitted to the power supply control module 63. The automatic grouping module 62 calculates the average power generation that each photovoltaic power generation device 1 should generate based on the load terminal voltage 5 and the number of photovoltaic power generation devices 1 in each photovoltaic power generation group, and transmits the average power generation that should generate to the power shortage compensation module 64.

[0033] like Figure 1 and Figure 2 As shown, the power supply control module 63, based on the information of the photovoltaic power generation group, divides the DC power output from the rectifier and voltage regulator 2 of the same photovoltaic power generation group and then inputs it into the same number of inverters 3 as the number of photovoltaic devices in the photovoltaic power generation group. The output terminals of the inverters 3 are electrically connected to the transformers 4, and the output terminals of the transformers 4 are connected in series. The inverters 3 and the transformers 4 are adjusted according to the voltage value of the load terminal 5 and the number of inverters 3. The DC power outputs AC power through each inverter 3, and the AC power is stepped up by the transformers 4 and then transmitted to the load terminal 5.

[0034] like Figure 1 and Figure 2As shown, the power shortage compensation module 64 divides all photovoltaic power generation units into multiple regional groups. Each regional group designates one photovoltaic power generation unit as a backup group. The output terminal of each transformer 4 in the backup group is electrically connected to the output terminal of one transformer 4 in another photovoltaic power generation unit. The output terminal of each photovoltaic power generation unit's transformer 4 is electrically connected to the output terminal of a transformer 4 in the backup group. A normally open switch 641 is connected in series at the connection point between the output terminal of each photovoltaic power generation unit's transformer 4 and the transformer 4 in the backup group. The module 61 collects the voltage at the output terminal of each rectifier and voltage regulator 2 and the total voltage output by each photovoltaic power generation unit to the load terminal 5. When the voltage at the output of any rectifier and voltage regulator 2 is lower than the average expected power generation, and the total voltage output from the photovoltaic power generation group to the load terminal 5 is lower than the voltage value of the load terminal 5, the voltage output of the other transformers 4 in the photovoltaic power generation group to which the rectifier and voltage regulator 2 is located is first increased based on the voltage difference between the output voltage of the rectifier and voltage regulator 2 and the average expected power generation, so that the total voltage output from the photovoltaic power generation group to the load terminal 5 is equal to the voltage value of the load terminal 5, and the control of the normally open switch 641 is suspended. If the voltage output of the other transformers 4 in the photovoltaic power generation group to which the rectifier and voltage regulator 2 is located cannot reach the increased voltage, the voltage increase is canceled, the control of the normally open switch 641 is restored, the rectifier and voltage regulator 2 is disconnected, and the normally open switch 641 between the transformer 4 corresponding to the rectifier and voltage regulator 2 and the transformer 4 of the standby group electrically connected to it is closed.

[0035] Multiple photovoltaic (PV) generators are divided into a large regional group, and one PV generator is selected as a standby group. The AC power output of the standby group can be used for equipment with low voltage requirements or that can be shut down at any time. When the DC power output of any PV generator 1 decreases below the average expected power output, the system will suspend the operation of the line where PV generator 1 is located and disconnect a corresponding line from the standby group to connect it to the PV generator missing PV generator 1, ensuring that the final output AC voltage value can reach the voltage value required by the load terminal 5. Before suspending the operation of the line where PV generator 1 is located, the system will first attempt to compensate with the power output of other PV generator 1s. If compensation fails, the system will then suspend the operation of the line where PV generator 1 is located and activate the standby group.

[0036] The power shortage compensation module 64 calculates that when the sum of the voltage difference between the output voltage of transformer 4 in the regional group and the average expected power generation voltage is greater than the voltage value at the load end 5, it issues an alarm and suspends the connection between all photovoltaic power generation units connected to transformer 4 whose output voltage is lower than the average expected power generation and the load end 5, and issues an alarm. If the power output of the entire regional group drops significantly, causing the backup group to be insufficient to compensate for the power loss of other photovoltaic power generation units, it abandons the photovoltaic power generation units with the huge power drop, suspends their operation, and issues an alarm to remind users.

[0037] like Figure 1 As shown, the automatic grouping module 62 presets a voltage change limit, which is calculated based on the average output power of the current photovoltaic power generation equipment 1. When a new load terminal 5 voltage value is received and it covers the original load terminal 5 voltage value, the new average expected power generation is calculated based on the new load terminal 5 voltage value and the number of photovoltaics in the current photovoltaic power generation group. The difference between the new average expected power generation and the current average expected power generation is calculated, and it is determined whether the difference is greater than the voltage change limit. If the difference is less than the voltage change limit, the photovoltaic power generation equipment 1 is controlled to disconnect, and the rectifier and voltage regulator 2, inverter 3 or transformer 4 is adjusted according to the new average expected power generation. Then, the photovoltaic power generation equipment 1 is controlled to make the output voltage of the photovoltaic power generation group reach the new average expected power generation. If the difference is greater than the voltage change limit, the minimum number of photovoltaics required for each group is recalculated based on the new load terminal 5 voltage value and the average output voltage value of the photovoltaic power generation equipment 1. If the voltage required at load terminal 5 changes after switching to a new load, the system can first determine whether the voltage change can be compensated by adjusting the hardware parameters. If the original photovoltaic power generation unit cannot meet the voltage requirements of the new load terminal 5, the circuit and system can then be reconfigured.

[0038] The implementation principle of a low-cost photovoltaic grid-connected high-voltage power supply control system in this application embodiment is as follows: According to the voltage requirements of the load terminal 5, the system automatically divides the photovoltaic system into multiple photovoltaic power generation groups. The current generated by the photovoltaic power generation equipment 1 in the same group is combined and then split between the inverters 3 to obtain the same voltage value. After being adjusted by the transformer 4, it is combined into AC power that meets the voltage requirements of the load terminal 5. This ensures that the load terminal 5 can obtain the required high-voltage AC power, and also effectively reduces the power supply cost by using multiple small transformers 4 to replace the large transformer 4.

[0039] Example 2: This application discloses a low-cost photovoltaic grid-connected high-voltage power supply control method, the specific steps of which are as follows: S100, preset load terminal 5 voltage value and voltage variation limit, the voltage variation limit is calculated based on the average output power of the current photovoltaic power generation equipment 1.

[0040] S101. Connect all photovoltaic power generation devices 1 to the system and calculate the number of photovoltaics.

[0041] S200: Collect the voltage value output by each photovoltaic power generation device 1 connected to the system within a set time period, calculate the average voltage value output by each photovoltaic power generation device 1, and then calculate the average voltage value output by all photovoltaic power generation devices 1.

[0042] S201. Calculate the minimum number of photovoltaic units required for each group based on the voltage value at the load terminal 5 and the average voltage value output by the photovoltaic power generation equipment 1.

[0043] S202. Each photovoltaic power generation device 1 is equipped with a rectifier and voltage regulator 2 at its output terminal to output DC power.

[0044] S203. Based on the DC power output of the rectifier and voltage regulator 2 and the minimum number of photovoltaic cells required for each group, divide the photovoltaic power generation groups and connect the output terminals of the rectifier and voltage regulator 2 in series within the same photovoltaic power generation group.

[0045] S204. The DC power output from the rectifier and voltage regulator 2 of the same photovoltaic power generation group is shunted and then input into the same number of inverters 3 as the number of photovoltaic devices in the photovoltaic power generation group. The output terminals of inverters 3 are electrically connected to transformers 4, and the output terminals of transformers 4 are connected in series. The inverters 3 and transformers 4 are adjusted according to the voltage value of the load terminal 5 and the number of inverters 3.

[0046] S205. DC power is output as AC power through each inverter 3. The AC power is stepped up by transformer 4 and then transmitted to the load terminal 5.

[0047] S300. Calculate the average power generation of each photovoltaic power generation device 1 based on the voltage value of the load terminal 5 and the number of photovoltaic power generation devices 1 in each photovoltaic power generation group.

[0048] S400. Divide all photovoltaic power generation units into multiple regional groups. Each regional group uses one of the photovoltaic power generation units as a backup group. Connect the output terminal of each transformer 4 in the backup group to the output terminal of one transformer 4 in another photovoltaic power generation unit. The output terminal of each transformer 4 in the photovoltaic power generation unit is connected to the output terminal of a transformer 4 in the backup group. A normally open switch 641 is connected in series at the connection point between the output terminal of each photovoltaic power generation unit and the transformer 4 in the backup group.

[0049] S401. Detect the voltage at the output terminal of each rectifier and voltage regulator 2 and the total voltage output by each photovoltaic power generation unit to the load terminal 5.

[0050] S402. When the voltage at the output terminal of any rectifier and voltage regulator 2 is lower than the average power generation, and the total voltage output from the photovoltaic power generation group where the rectifier and voltage regulator 2 is located to the load terminal 5 is lower than the voltage value of the load terminal 5, the voltage output of other transformers 4 of the photovoltaic power generation group where the rectifier and voltage regulator 2 is located is increased according to the voltage difference between the output voltage of the rectifier and voltage regulator 2 and the average power generation, so that the total voltage output from the photovoltaic power generation group where the rectifier and voltage regulator 2 is located to the load terminal 5 is equal to the voltage value of the load terminal 5, and the control of the normally open switch 641 is suspended.

[0051] S403. If the voltage output of other transformers 4 in the photovoltaic power generation group where the rectifier and voltage regulator 2 is located cannot reach the improved voltage, then cancel the voltage improvement, restore the control of the normally open switch 641, disconnect the rectifier and voltage regulator 2, and close the normally open switch 641 between the transformer 4 corresponding to the rectifier and voltage regulator 2 and the transformer 4 of the standby group that is electrically connected.

[0052] Multiple photovoltaic (PV) generators are divided into a large regional group, and one PV generator is selected as a standby group. The AC power output of the standby group can be used for equipment with low voltage requirements or that can be shut down at any time. When the DC power output of any PV generator 1 decreases below the average expected power output, the system will suspend the operation of the line where PV generator 1 is located and disconnect a corresponding line from the standby group to connect it to the PV generator missing PV generator 1, ensuring that the final output AC voltage value can reach the voltage value required by the load terminal 5. Before suspending the operation of the line where PV generator 1 is located, the system will first attempt to compensate with the power output of other PV generator 1s. If compensation fails, the system will then suspend the operation of the line where PV generator 1 is located and activate the standby group.

[0053] S500: When the sum of the voltage differences between the output voltage of transformer 4 in the regional photovoltaic power generation group and the average expected power generation voltage is greater than the voltage value of load terminal 5, an alarm is issued and the connection between all photovoltaic power generation groups connected to transformer 4 whose output voltage is lower than the average expected power generation and load terminal 5 is suspended, and an alarm is issued. If the power output of the entire regional photovoltaic power generation group drops significantly, causing the backup group to be insufficient to compensate for the power loss of other photovoltaic power generation groups, the photovoltaic power generation groups with a significant drop in output power are abandoned, causing them to stop working, and an alarm is issued to remind users.

[0054] S600 When a new load terminal 5 voltage value is received that overrides the original load terminal 5 voltage value, a new average power generation should be calculated based on the new load terminal 5 voltage value and the number of photovoltaic cells in the current photovoltaic power generation group.

[0055] S601. Calculate the difference between the new average expected power generation and the current average expected power generation, and determine whether the difference is greater than the voltage change limit.

[0056] S602. If the difference is less than the voltage change limit, control the photovoltaic power generation equipment 1 to disconnect and adjust the rectifier and voltage regulator 2, inverter 3 or transformer 4 according to the new average power generation. Then control the photovoltaic power generation equipment 1 to make the output voltage of the photovoltaic power generation group reach the new average power generation.

[0057] S603. If the difference exceeds the voltage change limit, the minimum number of photovoltaic units required for each group is recalculated based on the new load terminal 5 voltage value and the average output voltage value of photovoltaic power generation equipment 1. If the required voltage value of load terminal 5 changes after switching to a new load, the system can first determine whether the voltage change can be compensated by adjusting hardware parameters. If the original photovoltaic power generation group cannot meet the new load terminal 5 voltage value requirement, the circuit and system are then reconfigured.

[0058] Based on the voltage requirements of the load terminal 5, the system automatically divides the photovoltaic system into multiple photovoltaic power generation groups. The current generated by the photovoltaic power generation equipment 1 in the same group is combined and then split between the inverters 3 to obtain the same voltage value. After being adjusted by the transformer 4, it is combined into AC power that meets the voltage requirements of the load terminal 5. This ensures that the load terminal 5 can obtain the required high-voltage AC power, and also effectively reduces the power supply cost by using multiple small transformers 4 instead of large transformers 4.

[0059] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A low-cost photovoltaic grid-connected high-voltage power supply control method, characterized in that, Includes the following steps: Preset the load terminal (5) voltage value; Connect all photovoltaic power generation devices (1) to the system and calculate the number of photovoltaic units; Collect the voltage value output by each photovoltaic power generation device (1) connected to the system within a set time period, calculate the average voltage value output by each photovoltaic power generation device (1), and then calculate the average voltage value output by all photovoltaic power generation devices (1); Calculate the minimum number of photovoltaic units required for each group based on the voltage value at the load end (5) and the average voltage value output by the photovoltaic power generation equipment (1); Each photovoltaic power generation device (1) is equipped with a rectifier and voltage regulator (2) at its output terminal to output DC power; Photovoltaic power generation groups are divided according to the DC power output of the rectifier and voltage regulator (2) and the minimum number of photovoltaics required for each group, and the output terminals of the rectifier and voltage regulator (2) in the same group are connected in series. The DC power output from the rectifier and voltage regulator (2) of the same photovoltaic power generation group is shunted and then input into the same number of inverters (3) as the number of photovoltaic devices in the photovoltaic power generation group. The output terminals of the inverters (3) are electrically connected to the transformers (4). The output terminals of the transformers (4) are connected in series. The inverters (3) and transformers (4) are adjusted according to the voltage value of the load terminal (5) and the number of inverters (3). DC power is output as AC power through each inverter (3), and AC power is stepped up by transformer (4) and then transmitted to the load (5).

2. The low-cost photovoltaic grid-connected high-voltage power supply control method according to claim 1, characterized in that, It also includes the following steps: The average power generation of each photovoltaic power generation device (1) is calculated based on the voltage value of the load terminal (5) and the number of photovoltaic power generation devices (1) in each photovoltaic power generation group; All photovoltaic power generation units are divided into multiple regional groups. Each regional group uses one of the photovoltaic power generation units as a backup group. The output terminal of each transformer (4) of the backup group is electrically connected to the output terminal of one transformer (4) of another photovoltaic power generation unit. The output terminal of the transformer (4) of each photovoltaic power generation unit is electrically connected to the output terminal of the transformer (4) of a backup group. A normally open switch (641) is connected in series at the connection point between the output terminal of the transformer (4) of each photovoltaic power generation unit and the transformer (4) of the backup group. Detect the voltage at the output of each rectifier and voltage regulator (2) and the total voltage output by each photovoltaic power generation unit to the load (5); When the voltage at the output terminal of any rectifier and voltage regulator (2) is lower than the average power generation, and the total voltage output from the photovoltaic power generation group to the load terminal (5) where the rectifier and voltage regulator (2) is located is lower than the voltage value of the load terminal (5), the rectifier and voltage regulator (2) is disconnected, and the normally open switch (641) between the transformer (4) corresponding to the rectifier and voltage regulator (2) and the transformer (4) of the standby group that is electrically connected is closed.

3. The low-cost photovoltaic grid-connected high-voltage power supply control method according to claim 2, characterized in that, It also includes the following steps: When the voltage at the output terminal of any rectifier and voltage regulator (2) is lower than the average power generation, the voltage output of other transformers (4) in the photovoltaic power generation group where the rectifier and voltage regulator (2) is located is increased according to the voltage difference between the output voltage of the rectifier and voltage regulator (2) and the average power generation, so that the total voltage output by the photovoltaic power generation group where the rectifier and voltage regulator (2) is located to the load terminal (5) is equal to the voltage value of the load terminal (5), and the control of the normally open switch (641) is suspended. If the voltage output of other transformers (4) in the photovoltaic power generation group where the rectifier and voltage regulator (2) is located cannot reach the increased voltage, then the voltage increase is canceled and the control of the normally open switch (641) is restored.

4. The low-cost photovoltaic grid-connected high-voltage power supply control method according to claim 2, characterized in that, It also includes the following steps: When the sum of the voltage difference between the output voltage of the transformer (4) in the large area group and the voltage difference between the average power generation capacity and the voltage value of the load terminal (5) is greater than the voltage value of the load terminal (5), an alarm is issued and the connection between all photovoltaic power generation groups with transformers (4) whose output voltage is lower than the average power generation capacity and the load terminal (5) is suspended, and an alarm is issued.

5. The low-cost photovoltaic grid-connected high-voltage power supply control method according to claim 1, characterized in that, It also includes the following steps: A preset voltage variation limit is set, which is calculated based on the average output power of the current photovoltaic power generation equipment (1). When a new load terminal (5) voltage value is received and it covers the original load terminal (5) voltage value, a new average power generation should be calculated based on the new load terminal (5) voltage value and the number of photovoltaics in the current photovoltaic power generation group. Calculate the difference between the new average expected power generation and the current average expected power generation, and determine whether the difference is greater than the voltage change limit; If the difference is less than the voltage change limit, the photovoltaic power generation equipment (1) is disconnected and the rectifier and voltage regulator (2), inverter (3) or transformer (4) is adjusted according to the new average power generation. Then the photovoltaic power generation equipment (1) is connected to the circuit so that the output voltage of the photovoltaic power generation unit reaches the new average power generation. If the difference is greater than the voltage change limit, the minimum number of photovoltaic units required for each group will be recalculated based on the new load terminal (5) voltage value and the average voltage value output by the photovoltaic power generation equipment (1).

6. A low-cost photovoltaic grid-connected high-voltage power supply control system, characterized in that: It includes multiple photovoltaic power generation devices (1) and a photovoltaic control system (6). Each photovoltaic power generation device (1) is electrically connected to a rectifier and voltage regulator (2). The photovoltaic control system (6) includes a data acquisition module (61), an automatic grouping module (62), and a power supply control module (63). The data acquisition module (61) acquires the DC voltage value output by the photovoltaic power generation equipment (1) and the DC voltage value output by the rectifier and voltage regulator (2), and transmits the DC voltage value output by the photovoltaic power generation equipment (1) and the DC voltage value output by the rectifier and voltage regulator (2) to the automatic grouping module (62). The automatic grouping module (62) presets a voltage change limit. The automatic grouping module (62) intercepts the voltage value output by each photovoltaic power generation device (1) within a set time, calculates the average voltage value output by each photovoltaic power generation device (1), and then calculates the average voltage value output by all photovoltaic power generation devices (1). Based on the voltage value of the load end (5) and the average voltage value output by the photovoltaic power generation device (1), it calculates the minimum number of photovoltaics required for each group. Based on the DC power output by the rectifier and voltage regulator (2) and the minimum number of photovoltaics required for each group, it divides the photovoltaic power generation groups, connects the output terminals of the rectifier and voltage regulator (2) in the same photovoltaic power generation group in series, and transmits the information of the same photovoltaic power generation group to the power supply control module (63). The power supply control module (63) uses the information of the photovoltaic power generation group in the same group to shunt the DC power output from the rectifier and voltage regulator (2) of the same group of photovoltaic power generation group and then inputs it into the same number of inverters (3) as the number of photovoltaic devices in the photovoltaic power generation group. The output terminals of the inverters (3) are electrically connected to the transformers (4). The output terminals of the transformers (4) are connected in series. The inverters (3) and transformers (4) are adjusted according to the voltage value of the load terminal (5) and the number of inverters (3). The DC power outputs AC power through each inverter (3). The AC power is stepped up by the transformer (4) and then transmitted to the load terminal (5).

7. A low-cost photovoltaic grid-connected high-voltage power supply control system according to claim 6, characterized in that: The photovoltaic control system (6) also includes a power shortage compensation module (64); The automatic grouping module (62) calculates the average power generation of each photovoltaic power generation device (1) based on the voltage value of the load end (5) and the number of photovoltaic power generation devices (1) in each photovoltaic power generation group, and transmits the average power generation to the power shortage compensation module (64); The data acquisition module (61) acquires the total voltage output by the photovoltaic power generation unit to the load terminal (5); The power shortage compensation module (64) divides all photovoltaic power generation units into multiple regional groups. Each regional group uses one of the photovoltaic power generation units as a backup group. The output terminal of each transformer (4) in the backup group is electrically connected to the output terminal of one transformer (4) in another photovoltaic power generation unit. The output terminal of each transformer (4) in the photovoltaic power generation unit is electrically connected to the output terminal of a transformer (4) in the backup group. A normally open switch (641) is connected in series at the connection point between the output terminal of each photovoltaic power generation unit's transformer (4) and the transformer (4) in the backup group. The data acquisition module is called. Block (61) collects the voltage at the output terminal of each rectifier and voltage regulator (2) and the total voltage output by each photovoltaic power generation group to the load terminal (5). When the voltage at the output terminal of any rectifier and voltage regulator (2) is lower than the average power generation, and the total voltage output by the photovoltaic power generation group to the load terminal (5) is lower than the voltage value of the load terminal (5), the rectifier and voltage regulator (2) is disconnected, and the normally open switch (641) between the transformer (4) corresponding to the rectifier and voltage regulator (2) and the transformer (4) of the standby group connected to the electric circuit is closed.

8. A low-cost photovoltaic grid-connected high-voltage power supply control system according to claim 7, characterized in that: When the voltage at the output terminal of any rectifier and voltage regulator (2) is lower than the average power generation, the power shortage compensation module (64) first increases the output voltage of other transformers (4) in the photovoltaic power generation group where the rectifier and voltage regulator (2) is located, based on the voltage difference between the output voltage of the rectifier and voltage regulator (2) and the average power generation, so that the total voltage output by the photovoltaic power generation group where the rectifier and voltage regulator (2) is located to the load terminal (5) is equal to the voltage value of the load terminal (5), and suspends the control of the normally open switch (641). If the output voltage of other transformers (4) in the photovoltaic power generation group where the rectifier and voltage regulator (2) is located cannot reach the increased voltage, the voltage increase is canceled and the control of the normally open switch (641) is restored.

9. A low-cost photovoltaic grid-connected high-voltage power supply control system according to claim 7, characterized in that: The power shortage compensation module (64) calculates that when the sum of the voltage difference between the output voltage of the transformer (4) in the large area group and the voltage of the average power generation is greater than the voltage value of the load end (5), it issues an alarm and suspends the connection between all photovoltaic power generation groups with transformers (4) whose output voltage is lower than the average power generation and the load end (5), and issues an alarm.

10. A low-cost photovoltaic grid-connected high-voltage power supply control system according to claim 6, characterized in that: The automatic grouping module (62) presets a voltage change limit. The voltage change limit is calculated based on the average output power of the current photovoltaic power generation equipment (1). When a new load terminal (5) voltage value is received and it covers the original load terminal (5) voltage value, the new average power generation should be calculated based on the new load terminal (5) voltage value and the number of photovoltaics in the current photovoltaic power generation group. The difference between the new average power generation and the current average power generation is calculated, and it is determined whether the difference is greater than the voltage change limit. If the difference is less than the voltage change limit, the photovoltaic power generation equipment (1) is controlled to disconnect and the rectifier and voltage regulator (2), inverter (3) or transformer (4) is adjusted according to the new average power generation. Then the photovoltaic power generation equipment (1) is controlled to make the output voltage of the photovoltaic power generation group reach the new average power generation. If the difference is greater than the voltage change limit, the minimum number of photovoltaics required for each group is recalculated based on the new load terminal (5) voltage value and the average output voltage value of the photovoltaic power generation equipment (1).

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