Power supply system and method based on photovoltaic power generation accessing electrolytic aluminum direct current bus

Abstract

The application discloses a power supply system and method based on photovoltaic power generation access to electrolytic aluminum DC bus. Using new energy power generation can reduce production cost, reduce environmental pollution, improve green electricity proportion, improve energy utilization efficiency, establish the required voltage by power storage on the photovoltaic power generation system side, do current stabilization treatment on the rectifier module side, further do current stabilization and voltage stabilization of the input bus, and ensure the reliability of electrolytic production safety; voltage stabilization treatment on the power generation side of the photovoltaic power supply system and current stabilization treatment on the rectification side can realize large-capacity photovoltaic power generation access to bus power supply, and automatic switching of power supply according to start-stop and fluctuation of photovoltaic power generation can be realized; long-distance transmission of photovoltaic power supply can also be realized; in addition, the photovoltaic rectifier module has small land occupation and easy field arrangement, and the requirement that the output end of the photovoltaic rectifier module is less than 10 meters away from the bus is conducive to insulation measures and reduction of accidents such as grounding and short circuit.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic power generation connected to the DC bus of electrolytic aluminum, specifically to a power supply system and method based on photovoltaic power generation connected to the DC bus of electrolytic aluminum, belonging to the technical field of new energy applications for electrolytic aluminum power supply. Background Technology

[0002] As energy-intensive enterprises, electrolytic aluminum companies have always been major electricity consumers in various regions. Furthermore, improving energy efficiency and reducing carbon emission intensity in the electrolytic aluminum industry, and better adapting to the future clean energy transition, utilizing new energy sources in electrolytic aluminum production is an urgent trend.

[0003] The method of using distributed photovoltaic power generation for the power supply rectification system of electrolytic aluminum plant (CN202210267727.0) has the following problems: (1) The photovoltaic power supply dedicated 35kV distribution device, photovoltaic power supply dedicated power supply rectifier unit, and photovoltaic power supply dedicated DC busbar must be located on the side of the power supply rectification system. First, it occupies a large area, and most electrolytic aluminum enterprises that have been put into operation are facing the predicament of having no land available; second, the distance between this scheme and the main busbar of the electrolytic cell is far, which is not conducive to doing a good job of insulation measures and reducing the occurrence of grounding, short circuit and other accidents. (2) Photovoltaic power generation is transmitted to the AC and directly input to the rectifier system after passing through a dedicated 35kV distribution device for photovoltaic power supply. Due to the influence of environmental factors, the power supply of photovoltaic power generation is characterized by frequent and large fluctuations. Without energy storage, the system cannot provide a stable voltage source. Without a stable voltage source, pure photovoltaic power generation is very difficult to control the voltage, which will cause the photovoltaic DC side energy to be unstable. After being connected to the DC bus of electrolytic aluminum, it cannot cope with grid interference and electromagnetic shocks when the electrolytic anode effect occurs. Moreover, the larger the photovoltaic capacity, the greater the impact. Summary of the Invention

[0004] To address the aforementioned technical problems, the purpose of this invention is to provide a power supply system and method based on photovoltaic power generation connected to the DC bus of electrolytic aluminum.

[0005] This invention protects a power supply system based on photovoltaic power generation connected to the DC bus of electrolytic aluminum, including a grid power supply system, a photovoltaic power supply system, an integrated monitoring and energy management system, a photovoltaic-storage total control system, a current stabilization system, a grid current signal acquisition module 1, a photovoltaic current signal acquisition module 2, a combiner bus 3, and a DC bus 4;

[0006] The power grid supply system is connected to the combiner bus 3 to provide grid current to the DC bus 4;

[0007] The photovoltaic power supply system is connected to the combiner bus 3 to provide photovoltaic current to the DC bus 4;

[0008] The integrated monitoring and energy management system is used to monitor the working status, output power, and energy storage operation of the photovoltaic power supply system.

[0009] The photovoltaic-storage overall control system is used to control the start-up and stop of energy storage, islanded grid operation, start-up and stop of photovoltaic power supply system, and coordination between photovoltaic power supply system and its supporting equipment;

[0010] The current stabilization system is used to control the target current of the input DC bus 4.

[0011] The power grid current signal acquisition module 1 is used to acquire the real-time current signal of the busbar.

[0012] The photovoltaic current signal acquisition module 2 is used to acquire real-time photovoltaic current signals.

[0013] Furthermore, the power grid supply system and the photovoltaic power supply system are connected to the combiner bus 3 in parallel.

[0014] Furthermore, the power grid supply system includes a power grid rectifier transformer, a saturated reactor, a power grid rectifier unit, and a rectifier cabinet connected in sequence. The rectifier cabinet is connected to a DC bus 4 via a busbar 3. A power grid current signal acquisition module 1 is installed between the busbar 3 and the DC bus 4. One end of the power grid current signal acquisition module 1 is connected to one end of the current stabilization system. The other end of the current stabilization system is connected to the saturated reactor.

[0015] Furthermore, the photovoltaic power supply system includes a photovoltaic power generation and boost module and a rectifier module connected in sequence; the photovoltaic power generation and boost module includes distributed photovoltaic modules, an inverter (DC / AC) and a boost transformer; the rectifier module includes a photovoltaic power supply rectifier transformer and a photovoltaic power supply rectifier unit; the photovoltaic power supply rectifier unit is connected to the DC bus 4 through the busbar 3, and a photovoltaic current signal acquisition module 2 is provided between the photovoltaic power supply rectifier unit and the busbar 3; one end of the photovoltaic current signal acquisition module 2 is connected to the current stabilization system.

[0016] The optimized connection distance between the output end of the rectifier module and the input end of the busbar 3 is less than 10 meters. The overhead transmission is carried out using exposed bare aluminum wires with a low-voltage DC voltage of 1.3KV.

[0017] In an optimized configuration, the step-up transformer and the photovoltaic power supply rectifier transformer are connected via a high-voltage cable.

[0018] Furthermore, the integrated monitoring and energy management system is connected to the distributed photovoltaic modules, inverters (DC / AC), step-up transformers, photovoltaic power supply rectifier transformers, photovoltaic power supply rectifier units, and the photovoltaic-storage overall control system, respectively.

[0019] Furthermore, a voltage source is connected between the inverter (DC / AC) and the step-up transformer, and the other end of the voltage source is connected to the integrated monitoring and energy management system.

[0020] This invention also protects a power supply method for a power supply system based on photovoltaic power generation connected to the DC bus of electrolytic aluminum, the specific steps of which include the following:

[0021] Step 1: The grid power supply is connected to the grid power supply rectifier transformer, saturated reactor, grid power supply rectifier unit and rectifier cabinet in sequence. The input AC power is rectified and output as DC power and connected to the busbar 3. Then the DC power is connected from the busbar 3 to the DC busbar 4.

[0022] Step 2: The distributed photovoltaic modules that form a photovoltaic power generation array in series output DC.

[0023] Step 3: The DC power output from the distributed photovoltaic modules is input into the inverter (DC / AC), and after conversion by the inverter (DC / AC), AC power is output.

[0024] Step 4: The AC input step-up transformer, after being converted by the inverter (DC / AC), completes the voltage boosting;

[0025] Step 5: After the high voltage is stepped up, it is transmitted over a long distance and input into the photovoltaic power supply rectifier transformer to output low voltage AC power that is compatible with the voltage of the electrolytic series.

[0026] Step 6: The low-voltage AC power output from the photovoltaic power supply rectifier transformer is input into the photovoltaic power supply rectifier unit, and after rectification by the photovoltaic rectifier unit, it outputs DC power of the same level.

[0027] Step 7: The DC power output by the photovoltaic rectifier unit is transmitted overhead to the busbar 3 using exposed hard aluminum wires, and then connected to the DC busbar 4 from the busbar 3.

[0028] Step 8: The integrated monitoring and energy management system monitors the working status of the photovoltaic power supply system and feeds it back to the photovoltaic-storage central control system in real time. The photovoltaic-storage central control system controls the operating status of the photovoltaic power supply system based on the real-time monitoring of the photovoltaic power supply system's operating status.

[0029] Step 9: The grid current signal acquisition module 1 will feed back the detected real-time current signal of the busbar and the photovoltaic current signal acquisition module 2 will feed back the detected photovoltaic current signal to the current stabilization system.

[0030] Step 10: The target current adjustment program in the current stabilization system generates the adjusted target current of the grid-powered rectifier unit based on the detected real-time current signal of the busbar and the photovoltaic current signal; wherein, the target current is the difference between the grid current connected to the busbar 3 and the photovoltaic current connected to the busbar 3.

[0031] Step 11: The current stabilization system adjusts the output of the saturated reactor to form the adjusted total target current of the grid-powered rectifier unit based on the target current mentioned above, thereby realizing automatic current stabilization control of the total target current output by the grid-powered rectifier unit.

[0032] Furthermore, the step-up transformer is selected with appropriate transformer level and high-voltage transmission cable type according to the transmitted power and distance.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) Achieve voltage stabilization on the power generation side of the photovoltaic power supply system.

[0035] An energy storage device voltage source (electrochemical energy storage) is connected between the inverter and the step-up transformer on the photovoltaic power supply system side. The voltage source supports the normal operation of the AC system and stabilizes the voltage.

[0036] (2) Further current stabilization control is implemented on the rectifier side of the photovoltaic power supply system to realize automatic switching of power supply on the grid side according to the start-up and fluctuation of photovoltaic power generation.

[0037] A target current adjustment program (the current value is determined by the photovoltaic power generation capacity) has been added to the current stabilization system of the grid power supply system. A photovoltaic real-time current signal acquisition module has been installed on the output side of the photovoltaic power supply rectifier unit, and the acquired real-time current signal is connected to the current stabilization system. When the current stabilization system detects the real-time DC current signal of the photovoltaic power supply system connected to the busbar, it subtracts the photovoltaic current from the total output current to form the adjusted total target current of the grid power supply rectifier unit. The current stabilization system then automatically adjusts the current stabilization control by adjusting the output of the saturated reactor based on the new target current.

[0038] (3) It can realize the supply of large-capacity photovoltaic power to the busbar.

[0039] After the photovoltaic power supply system is connected to the busbar, the actual current consists of the grid supply current and the photovoltaic supply current. During normal production of the electrolytic cell, the required current is a relatively stable constant (the current value changes by no more than ±0.5%). The current input to the DC bus required for its production must remain relatively stable. The larger the proportion of the input photovoltaic power supply current, the smaller the proportion of the grid supply current. Because electrolytic aluminum enterprises have extremely high requirements for power supply load, a stable current input to the DC bus is needed. However, photovoltaic power supply is limited by its own characteristics and is difficult to apply to the DC bus of electrolytic aluminum. Moreover, due to the fluctuation of its power supply, the more current supplied to the busbar, the greater the impact on electrolytic production. This invention can effectively reduce the fluctuation of photovoltaic power supply and realize the supply of large-capacity photovoltaic power to the DC bus of electrolytic aluminum.

[0040] (4) It can realize long-distance photovoltaic power supply.

[0041] Given the large land area required for photovoltaic power generation, this invention uses a high-voltage cable to transmit power between the step-up transformer and the photovoltaic power supply rectifier transformer, enabling long-distance transmission of photovoltaic power without being restricted by the installation location of the photovoltaic power supply.

[0042] (5) The photovoltaic rectifier module has a small footprint and high feasibility for on-site installation.

[0043] The connection distance between the rectifier module output terminal and the busbar access terminal is less than 10 meters. The short access distance is conducive to good insulation measures and reduces the incidence of grounding, short circuit and other accidents. The small footprint of the on-site installation is conducive to the on-site installation of the power supply system of the electrolytic aluminum enterprise that has been put into operation.

[0044] In summary, this invention reduces production costs, minimizes environmental pollution, increases the proportion of green electricity, and improves energy efficiency by using new energy power generation. It establishes the required operating voltage by incorporating energy storage on the photovoltaic power generation system side and performs current stabilization on the rectifier module side, further ensuring the stability of the input busbar and guaranteeing the reliability and safety of electrolytic production. Because voltage stabilization is implemented on the photovoltaic power generation side and current stabilization on the rectifier side, large-capacity photovoltaic power generation can be connected to the busbar for power supply. It also allows for automatic switching of grid power supply based on the start-up, shutdown, and fluctuations of photovoltaic power generation. Furthermore, it enables long-distance transmission of photovoltaic power. Additionally, the photovoltaic rectifier module has a small footprint and is easy to install on-site. The requirement that the output end of the photovoltaic rectifier module be less than 10 meters from the busbar facilitates insulation measures and reduces the occurrence of grounding, short-circuit, and other accidents. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the overall structure of the system of the present invention;

[0046] Figure 2 This is a flowchart illustrating the power supply process of the system of the present invention.

[0047] In the diagram: 1. Grid current signal acquisition module; 2. Photovoltaic current signal acquisition module; 3. Busbar; 4. DC bus. Detailed Implementation

[0048] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] Example 1

[0050] The process of system optimization and improvement of this invention

[0051] (1) Original plan: The original busbar power supply was all supplied by the power grid, and the actual power consumption of the electrolytic cell was equal to that supplied by the power grid.

[0052] (2) Scheme 1: With the goal of reducing grid power supply, Scheme 1 was designed, in which photovoltaic power generation is connected in parallel at the busbar. In this way, the target current of the busbar = grid current + photovoltaic current; and the measured grid current = target current of the busbar - photovoltaic current. By using self-provided photovoltaic power generation to replace part of the grid power consumption, the power consumption of grid power supply is reduced under the premise that the current supplied to the busbar remains unchanged. At this time, the number of power metering points is reduced accordingly, thereby achieving the goal of reducing the comprehensive AC power consumption of aluminum liquid.

[0053] (3) Scheme 2: Taking a 20MW photovoltaic power generation capacity and a 35kV voltage level for transmission as an example: Photovoltaic power generation is DC power, and the output DC voltage is less than DC1500V. The output DC power is input into the photovoltaic inverter (DC / AC) and then outputs AC power. The output AC voltage of the photovoltaic inverter is about AC800V. The output AC power is input into the step-up transformer and outputs AC35kV AC power. The purpose of stepping up is to achieve long-distance transmission. Then it is input into the rectifier transformer and outputs AC1320V AC power. Then it is input into the rectifier unit. After rectification, the output is stepped up by the step-up transformer. After stepping up to 35KV, it is sent to the rectifier transformer to output 1320V AC power and then sent to the rectifier unit (AC / DC). After rectification, the output of about 1320V DC power is connected to the busbar. A voltage source (electrochemical energy storage) is connected between the photovoltaic inverter and the step-up transformer. The voltage source supports the normal operation of the AC system and stabilizes the voltage. When the photovoltaic power generation system fluctuates, it compensates for the output.

[0054] The photovoltaic system is divided into photovoltaic power generation, step-up transformer, and rectifier module. The step-up transformer and rectifier transformer are connected by a high-voltage cable. The power generation section can be arranged over long distances, while the rectifier section needs to be arranged near the busbar. The distance from the output end of the rectifier unit to the connection point of the busbar should be less than 10 meters. Since the DC output busbar of the rectifier unit is a bare conductor made of hard aluminum, short-distance arrangement is conducive to good insulation measures and reduces the occurrence of accidents such as grounding and short circuits.

[0055] However, the above scheme has a problem: the stability requirements of the power supply system in electrolysis production are extremely high, and photovoltaic power generation has insufficient stability. Therefore, Scheme 3 was designed.

[0056] (4) Option 3: To ensure the reliability of photovoltaic power generation, an integrated monitoring and energy management system and a photovoltaic-storage total control system electrical secondary equipment are connected to the photovoltaic power generation system. The integrated monitoring and energy management system monitors the working status, output power and energy storage operation of the photovoltaic power generation system; the photovoltaic-storage total control system controls the start and stop of energy storage, islanded operation, start and stop of photovoltaic power generation, and coordination between photovoltaic power generation and rectifier units.

[0057] Taking into account the following two issues that need to be addressed when connecting photovoltaic power generation to the combiner bus, a fourth solution was designed:

[0058] Question 1: Photovoltaic power generation mainly occurs during the day, and its operation mode is to supply power during the day and stop supplying power at night. Therefore, the original power supply system operators need to perform corresponding voltage adjustment work every day according to the characteristics of photovoltaic power supply and the photovoltaic power supply situation.

[0059] Question 2: After the photovoltaic power generation system is connected to the combiner bus, due to its volatility, although there is compensation from electrochemical energy storage, there will still be slight fluctuations. These fluctuations will have a certain impact on the current stabilization system of the original control system (grid power supply).

[0060] (5) Option 4: Set up a current signal acquisition point at the DC measurement of the photovoltaic power generation system to collect the real-time DC current of the photovoltaic power generation system connected to the busbar. Connect the acquired signal to the current stabilization system in the original control system. When the current stabilization system detects the real-time DC current of the photovoltaic system connected to the busbar, it subtracts the photovoltaic current from the total output current to form the total target current after adjustment of the rectifier unit. This target current will be distributed in the rectifier unit. Then, a control command will be issued to adjust the saturated reactor to achieve current stabilization control of the busbar. Therefore, the original current stabilization system needs to be upgraded and modified to add a current target value adjustment program to achieve automatic current stabilization adjustment control.

[0061] For example, before the photovoltaic system is connected, the current signal acquired by the grid current signal acquisition module is assumed to be 240kA, and its current stabilization control will be based on 240kA. After the photovoltaic system is connected, the current signal acquired by the grid current signal acquisition module is assumed to be 240kA, and the current signal acquired by the photovoltaic current signal acquisition module is assumed to be 40kA. Its current stabilization control will be based on the newly formed target current. The target current = grid current signal value minus photovoltaic current signal value = 200kA. In other words, the current stabilization system will be controlled with 200kA as the target current.

[0062] In summary, the system protected by this application is obtained, as detailed in Examples 2 and 3.

[0063] Example 2

[0064] Please see the appendix Figure 1The present invention relates to a power supply system based on photovoltaic power generation connected to the DC bus of electrolytic aluminum, comprising a grid power supply system, a photovoltaic power supply system, an integrated monitoring and energy management system, a photovoltaic-storage total control system, a current stabilization system, a grid current signal acquisition module 1, a photovoltaic current signal acquisition module 2, a busbar 3, and a DC busbar 4. The grid power supply system is connected to the busbar 3 to provide grid current to the DC busbar 4; the photovoltaic power supply system is connected to the busbar 3 to provide photovoltaic current to the DC busbar 4; the integrated monitoring and energy management system is used to monitor the operating status, output power, and energy storage operation of the photovoltaic power supply system; the photovoltaic-storage total control system is used to control the start-up and stop of energy storage, islanded operation, start-up and stop of the photovoltaic power supply system, and coordination between the photovoltaic power supply system and its supporting equipment; the current stabilization system is used to perform current stabilization control on the target current input to the DC busbar 4; the grid current signal acquisition module 1 is used to acquire the real-time current signal of the busbar; and the photovoltaic current signal acquisition module 2 is used to acquire the real-time photovoltaic current signal.

[0065] In an optimized configuration, the grid power supply system and the photovoltaic power supply system are connected to the combiner bus 3 in parallel.

[0066] The optimized power grid supply system includes a power grid rectifier transformer, a saturated reactor, a power grid rectifier unit, and a rectifier cabinet connected in sequence. The rectifier cabinet is connected to the DC bus 4 via a busbar 3. A power grid current signal acquisition module 1 is installed between the busbar 3 and the DC bus 4. One end of the power grid current signal acquisition module 1 is connected to one end of the current stabilization system. The other end of the current stabilization system is connected to the saturated reactor.

[0067] The optimized photovoltaic power supply system includes a photovoltaic power generation and boost module and a rectifier module connected in sequence; the photovoltaic power generation and boost module includes distributed photovoltaic modules, an inverter (DC / AC) and a boost transformer; the rectifier module includes a photovoltaic power supply rectifier transformer and a photovoltaic power supply rectifier unit; the photovoltaic power supply rectifier unit is connected to the DC bus 4 through the busbar 3, and a photovoltaic current signal acquisition module 2 is installed between the photovoltaic power supply rectifier unit and the busbar 3; one end of the photovoltaic current signal acquisition module 2 is connected to the current stabilization system.

[0068] The optimized connection distance between the output end of the rectifier module and the input end of the busbar 3 is less than 10 meters. It uses exposed bare aluminum wires for overhead transmission, and the wire voltage is 1.3KV low-voltage DC.

[0069] In the optimized configuration, the step-up transformer and the photovoltaic power supply rectifier transformer are connected via a high-voltage cable.

[0070] The optimized integrated monitoring and energy management system is connected to the distributed photovoltaic modules, inverters (DC / AC), step-up transformers, photovoltaic power supply rectifier transformers, photovoltaic power supply rectifier units, and the photovoltaic-storage overall control system.

[0071] In the optimized configuration, a voltage source is connected between the inverter (DC / AC) and the step-up transformer, and the other end of the voltage source is connected to the integrated monitoring and energy management system.

[0072] Example 3

[0073] Based on Example 1, please refer to the appendix. Figure 1-2 The power supply method for a power supply system based on photovoltaic power generation connected to the DC bus of electrolytic aluminum includes the following specific steps:

[0074] Step 1: The grid power supply is connected to the grid power supply rectifier transformer, saturated reactor, grid power supply rectifier unit and rectifier cabinet in sequence. The input AC power is rectified and output as DC power and connected to the busbar 3. Then the DC power is connected from the busbar 3 to the DC busbar 4.

[0075] Step 2: The distributed photovoltaic modules that form a photovoltaic power generation array in series output DC.

[0076] Step 3: The DC power output from the distributed photovoltaic modules is input into the inverter (DC / AC), and after conversion by the inverter (DC / AC), AC power is output.

[0077] Step 4: The AC input step-up transformer, after being converted by the inverter (DC / AC), completes the voltage boosting;

[0078] Step 5: After the high voltage is stepped up, it is transmitted over a long distance and input into the photovoltaic power supply rectifier transformer to output low voltage AC power that is compatible with the voltage of the electrolytic series.

[0079] Step 6: The low-voltage AC power output from the photovoltaic power supply rectifier transformer is input into the photovoltaic power supply rectifier unit, and after rectification by the photovoltaic rectifier unit, it outputs DC power of the same level.

[0080] Step 7: The DC power output by the photovoltaic rectifier unit is transmitted overhead to the busbar 3 using exposed hard aluminum wires, and then connected to the DC busbar 4 from the busbar 3.

[0081] Step 8: The integrated monitoring and energy management system monitors the working status of the photovoltaic power supply system and feeds it back to the photovoltaic-storage central control system in real time. The photovoltaic-storage central control system controls the operating status of the photovoltaic power supply system based on the real-time monitoring of the photovoltaic power supply system's operating status.

[0082] Step 9: The grid current signal acquisition module 1 will feed back the detected real-time current signal of the busbar and the photovoltaic current signal acquisition module 2 will feed back the detected photovoltaic current signal to the current stabilization system.

[0083] Step 10: The target current adjustment program in the current stabilization system generates the adjusted target current of the grid-powered rectifier unit based on the detected real-time current signal of the busbar and the photovoltaic current signal; wherein, the target current is the difference between the grid current connected to the busbar 3 and the photovoltaic current connected to the busbar 3.

[0084] Step 11: The current stabilization system adjusts the output of the saturated reactor to form the adjusted total target current of the grid-powered rectifier unit based on the target current mentioned above, thereby realizing automatic current stabilization control of the total target current output by the grid-powered rectifier unit.

[0085] The optimized step-up transformer selects the appropriate transformer level and high-voltage transmission cable type based on the amount of electricity transmitted and the distance.

[0086] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A power supply system based on photovoltaic power generation connected to the DC bus of electrolytic aluminum, characterized in that: It includes a power grid power supply system, a photovoltaic power supply system, an integrated monitoring and energy management system, a photovoltaic and energy storage total control system, a current stabilization system, a power grid current signal acquisition module (1), a photovoltaic current signal acquisition module (2), a busbar (3), and a DC busbar (4); The power grid supply system is connected to the busbar (3) to provide grid current to the DC busbar (4); The photovoltaic power supply system is connected to the busbar (3) to provide photovoltaic current to the DC busbar (4); The power grid power supply system and the photovoltaic power supply system are connected to the combiner bus in parallel (3); The power grid power supply system includes a power grid power supply rectifier transformer, a saturated reactor, a power grid power supply rectifier unit and a rectifier cabinet connected in sequence. The rectifier cabinet is connected to the DC bus (4) through a busbar (3). A power grid current signal acquisition module (1) is provided between the busbar (3) and the DC bus (4). The photovoltaic power supply system includes a photovoltaic power generation and boost module and a rectifier module connected in sequence; the photovoltaic power generation and boost module includes distributed photovoltaic modules, an inverter (DC / AC) and a boost transformer; the rectifier module includes a photovoltaic power supply rectifier transformer and a photovoltaic power supply rectifier unit; the photovoltaic power supply rectifier unit is connected to the DC bus (4) through a busbar (3), and a photovoltaic current signal acquisition module (2) is provided between the photovoltaic power supply rectifier unit and the busbar (3); The integrated monitoring and energy management system is used to monitor the working status, output power, and operation of the energy storage device of the photovoltaic power supply system. The photovoltaic-storage overall control system is used to control the start-up and stop of the energy storage device, islanded operation, start-up and stop of the photovoltaic power supply system, and coordination between the photovoltaic power supply system and its supporting equipment. The power grid current signal acquisition module (1) is used to acquire the real-time current signal of the busbar; the photovoltaic current signal acquisition module (2) is used to acquire the real-time DC current signal output by the photovoltaic power supply rectifier unit; One end of the power grid current signal acquisition module (1) is connected to one end of the current stabilization system; one end of the photovoltaic current signal acquisition module (2) is connected to the current stabilization system; the other end of the current stabilization system is connected to the saturated reactor. The current stabilization system is used to control the current of the input DC bus (4) and is configured to determine the difference between the grid current connected to the bus (3) and the photovoltaic current connected to the bus (3) as the target current based on the real-time current signal of the bus acquired by the grid current signal acquisition module (1) and the real-time DC current signal acquired by the photovoltaic current signal acquisition module (2), and to automatically control the current output of the grid-powered rectifier unit by adjusting the output of the saturated reactor according to the target current.

2. The power supply system based on photovoltaic power generation connected to the DC bus of electrolytic aluminum as described in claim 1, characterized in that: The connection distance between the output end of the rectifier module and the input end of the busbar (3) is less than 10 meters. The overhead transmission is carried out using bare aluminum wires and the wire voltage is 1.3KV low-voltage DC.

3. The power supply system based on photovoltaic power generation connected to the DC bus of electrolytic aluminum as described in claim 1, characterized in that: The step-up transformer and the photovoltaic power supply rectifier transformer are connected by a high-voltage cable. The high-voltage AC power output by the step-up transformer is transmitted over a long distance via the high-voltage cable and then input to the photovoltaic power supply rectifier transformer.

4. The power supply system based on photovoltaic power generation connected to the DC bus of electrolytic aluminum as described in claim 1, characterized in that: The integrated monitoring and energy management system is connected to the distributed photovoltaic modules, inverters (DC / AC), step-up transformers, photovoltaic power supply rectifier transformers, photovoltaic power supply rectifier units, and the photovoltaic-storage overall control system.

5. The power supply system based on photovoltaic power generation connected to the DC bus of electrolytic aluminum as described in claim 1, characterized in that: A voltage source is connected between the inverter (DC / AC) and the step-up transformer, and the other end of the voltage source is connected to the integrated monitoring and energy management system.

6. The power supply method for a power supply system based on photovoltaic power generation connected to the DC bus of electrolytic aluminum, according to any one of claims 1-5, is characterized in that: The specific steps include the following: Step 1: The grid power supply is connected to the grid power supply rectifier transformer, saturated reactor, grid power supply rectifier unit and rectifier cabinet in sequence. The input AC power is rectified and output DC power is connected to the busbar (3). Then the DC power is connected from the busbar (3) to the DC busbar (4). Step 2: The distributed photovoltaic modules, which are connected in series to form a photovoltaic power generation array, output DC. Step 3: The DC power output from the distributed photovoltaic modules is input into the inverter (DC / AC), and after conversion by the inverter (DC / AC), AC power is output. Step 4: The AC input step-up transformer, after being converted by the inverter (DC / AC), completes the voltage boosting; Step 5: After the high voltage is stepped up, it is transmitted over a long distance and input into the photovoltaic power supply rectifier transformer to output low voltage AC power that is compatible with the voltage of the electrolytic series. Step 6: The low-voltage AC power output from the photovoltaic power supply rectifier transformer is input into the photovoltaic power supply rectifier unit, and after rectification by the photovoltaic rectifier unit, it outputs DC power of the same level. Step 7: The DC power output by the photovoltaic rectifier unit is transmitted overhead to the busbar (3) using bare aluminum wires, and then connected to the DC busbar (4) from the busbar (3). Step 8: The integrated monitoring and energy management system monitors the working status of the photovoltaic power supply system and feeds it back to the photovoltaic-storage central control system in real time. The photovoltaic-storage central control system controls the operating status of the photovoltaic power supply system based on the real-time monitoring of the photovoltaic power supply system's operating status. Step 9: The grid current signal acquisition module (1) feeds back the detected real-time current signal of the busbar and the photovoltaic current signal acquisition module (2) feeds back the detected photovoltaic current signal to the current stabilization system. Step 10: The target current adjustment program in the current stabilization system generates the adjusted target current of the grid-powered rectifier unit based on the detected real-time current signal of the busbar and the photovoltaic current signal; wherein, the target current is the difference between the grid current connected to the busbar (3) and the photovoltaic current connected to the busbar (3); Step 11: The current stabilization system adjusts the output of the saturated reactor to form the adjusted total target current of the grid-powered rectifier unit based on the target current mentioned above, thereby realizing automatic current stabilization control of the total target current output by the grid-powered rectifier unit.

7. The power supply method for a power supply system based on photovoltaic power generation connected to the DC bus of electrolytic aluminum as described in claim 6, characterized in that: The step-up transformer is selected according to the power transmitted and the distance, with appropriate transformer level and high-voltage transmission cable type.

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