Energy storage type aluminum electrolysis cell power supply system and method for access absorption of green ionization network

Abstract

The invention relates to the technical field of electrolytic aluminum power supply, and discloses a green ionization grid access absorption energy storage type aluminum electrolysis cell power supply system and method.The system comprises a user side energy storage system connected with a bus, and the access end and the output end of the user side energy storage system are connected with a photovoltaic power generation direct current system and a power supply rectification system respectively; the bus is provided with a first isolating switch group and a fourth isolating switch group which are respectively arranged between the photovoltaic power generation direct current system and the user side energy storage system and between the user side energy storage system and the power supply rectification system, and the access end and the output end of the user side energy storage system are respectively provided with a second isolating switch group and a third isolating switch group; the method controls the on-off of the first to fourth isolation switch groups according to the output current of the photovoltaic power generation DC system. When the change rate of the output current of the photovoltaic power generation direct current system exceeds the accepting range of the electrolytic cell, the first, third and fourth isolation switch groups are closed, the second isolation switch group is disconnected, and the user side energy storage system supplies power. High adaptability is still achieved under the condition that high-capacity direct current is output through photovoltaic power generation, and the working stability of the electrolytic cell is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply for aluminum electrolytic cells, and in particular to an energy storage type power supply system and method for aluminum electrolytic cells capable of absorbing green electricity off-grid. Background Art

[0002] More and more aluminum plants are using the direct current generated by photovoltaic power generation systems to directly power the electrolytic cells. Figure 1 As shown, at this time, the current supply of the electrolyzer consists of two parts: one is powered by the power supply rectifier system, and the power comes from the power grid; the other is powered by the photovoltaic power generation DC system, and the power comes from the photovoltaic power generation DC system.

[0003] At present, when designing the power supply system of the electrolytic cell of the electrolytic aluminum plant and manufacturing the rectifier, the fluctuation range of the DC current is generally considered to be no more than ±5% of the electrolytic series current requirements. When the amplitude of the DC side power supply current of the photovoltaic power generation DC system does not exceed 5% of the electrolytic series current, the existing power supply rectifier system can be adjusted through the current stabilization control system so that the total current supplied to the electrolytic cell meets the needs of the electrolytic cell and ensures the stability of the DC power supply to the electrolytic cell. When the amplitude of the DC side power supply current of the photovoltaic power generation DC access system exceeds 5% of the electrolytic series current, the current exceeds the adjustment range of the current stabilization control system, and the electrolytic cell power supply system does not have other current stabilization means, so that the total current supplied to the electrolytic cell can meet the needs of the electrolytic cell, but cannot meet the stability requirements of the DC power supply to the electrolytic cell. Summary of the invention

[0004] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a green electricity off-grid access and consumption energy storage type aluminum electrolytic cell power supply system and method. The power supply system is provided with a user-side energy storage system and a first to fourth isolating switch group. The power supply method combines the opening and closing control of the isolating switch group under corresponding circumstances with the state control of the user-side energy storage system. The problem that the original electrolytic cell power supply system is difficult to work stably when the amplitude of the direct current output by photovoltaic power generation exceeds 5% of the electrolytic series current is solved. The power supply system of the electrolytic cell of the aluminum electrolytic plant is realized to have high adaptability when the photovoltaic power generation outputs a higher capacity direct current, thereby ensuring the stability of the operation of the electrolytic cell.

[0005] A green electricity off-grid access and consumption energy storage type aluminum electrolytic cell power supply system, comprising a photovoltaic power generation DC system, a power supply rectification system and an electrolytic cell connected through a busbar, and also comprising a user-side energy storage system connected to the busbar, wherein the access end of the user-side energy storage system is connected to the photovoltaic power generation DC system, and the output end is connected to the power supply rectification system; The busbar is provided with a first isolating switch group and a fourth isolating switch group. The first isolating switch group is provided between the photovoltaic power generation DC system and the user-side energy storage system, and the fourth isolating switch group is provided between the user-side energy storage system and the power supply rectifier system. The access end of the user-side energy storage system is provided with a second isolating switch group, and the output end is provided with a third isolating switch group.

[0006] By setting up a user-side energy storage system and the first to fourth isolating switch groups, the user-side energy storage system can be used to start supplying power when the rate of change of the output current of the photovoltaic power generation DC system exceeds the acceptance range of the electrolytic cell. This solves the problem that the electrolytic cell is difficult to work stably in the original electrolytic cell power supply system when the amplitude of the photovoltaic power generation output DC exceeds 5% of the electrolytic series current. The electrolytic cell power supply system of the aluminum electrolytic plant is highly adaptable when the photovoltaic power generation outputs a higher capacity DC power, thereby ensuring the stability of the electrolytic cell operation.

[0007] Furthermore, the user-side energy storage system includes a charging module, a discharging module, an isolation module, a control and protection module and an energy storage module. The charging module is used to input a part of the DC power emitted by the photovoltaic power generation DC system into the energy storage module for charging; the discharging module is used to output the electric energy of the energy storage module; the control and protection module is used to control the output voltage of the user-side energy storage system to be consistent with the voltage required by the electrolytic cell; there are two isolation modules, and the isolation modules are used to isolate the reverse flow of current. The two isolation modules are respectively a first isolation module and a second isolation module. The first isolation module is arranged at the access end of the user-side energy storage system, and the second isolation module is arranged at the output end of the user-side energy storage system.

[0008] An isolation module is provided to prevent the occurrence of a fault in which the current flows in the reverse direction.

[0009] Furthermore, the busbar includes a connecting busbar and a DC busbar, the photovoltaic power generation DC system is connected to the user-side energy storage system through the connecting busbar, the power supply rectifier system is connected to the electrolytic cell through the DC busbar, and the connecting busbar is connected to the DC busbar through a fourth isolating switch group.

[0010] A method for supplying power to an energy storage type aluminum electrolytic cell with off-grid access and consumption of green electricity, using an energy storage type aluminum electrolytic cell power supply system with off-grid access and consumption of green electricity, controlling the on and off of a first isolating switch group to a fourth isolating switch group according to the output current of a photovoltaic power generation DC system, thereby switching the operating state of a user-side energy storage system; When the rate of change of the output current of the photovoltaic power generation DC system exceeds the acceptance range of the electrolyzer, the first isolating switch group, the third isolating switch group and the fourth isolating switch group are closed, the second isolating switch group is disconnected, and the user-side energy storage system is in a power supply state.

[0011] By designing a power supply method, the problem that the original electrolytic cell power supply system was difficult to operate stably when the amplitude of the DC power output by photovoltaic power generation exceeded 5% of the electrolytic series current was solved. Combined with the opening and closing control of the isolation switch group in the corresponding situation and the state control of the user-side energy storage system, the electrolytic cell power supply system of the electrolytic aluminum plant was made highly adaptable when the photovoltaic power generation outputs a higher capacity DC power, thereby ensuring the stability of the electrolytic cell operation.

[0012] Furthermore, when the current value output by the photovoltaic power generation DC system is higher than the current value required by the electrolytic cell, the first isolating switch group, the second isolating switch group and the fourth isolating switch group are closed, and the third isolating switch group is disconnected, so that the photovoltaic power generation DC system can supply power to the electrolytic cell normally while transmitting excess electric energy to the user-side energy storage system, and the user-side energy storage system is in an energy storage state.

[0013] Furthermore, when the current value output by the photovoltaic power generation DC system is within the current value range required by the electrolyzer, the first isolating switch group and the fourth isolating switch group are closed, and the second isolating switch group and the third isolating switch group are disconnected, so that the photovoltaic power generation DC system can supply power to the electrolyzer normally, and the user-side energy storage system is in standby mode.

[0014] Furthermore, when the current value output by the photovoltaic power generation DC system is less than the current value required by the electrolyzer, and the rate of change of the output current of the photovoltaic power generation DC system is within the acceptable range of the electrolyzer, the first isolating switch group and the fourth isolating switch group are closed, and the second isolating switch group and the third isolating switch group are disconnected, the photovoltaic power generation DC system supplies power to the electrolyzer normally, and the user-side energy storage system is in standby mode.

[0015] Furthermore, when the current value output by the photovoltaic power generation DC system is less than the current value required by the electrolyzer, and the rate of change of the output current of the photovoltaic power generation DC system exceeds the acceptable range of the electrolyzer, the first isolating switch group, the third isolating switch group and the fourth isolating switch group are closed, the second isolating switch group is disconnected, the user-side energy storage system is in a power supply state, and the photovoltaic power generation DC system and the user-side energy storage system simultaneously supply power to the electrolyzer. Ensure that the rate of change of the current supplied to the electrolyzer is within the acceptable range of the electrolyzer, thereby ensuring the stable operation of the electrolyzer.

[0016] Furthermore, when the photovoltaic power generation DC system stops operating and the output current value is 0A, the third and fourth isolating switch groups are closed, the first and second isolating switch groups are disconnected, the photovoltaic power generation DC system stops supplying power to the electrolyzer, and the user-side energy storage system is in a power supply state to supply power to the electrolyzer. Ensure that the current change rate supplied to the electrolyzer is within the acceptable range of the electrolyzer, thereby ensuring the stable operation of the electrolyzer.

[0017] Furthermore, when the power supply rectifier system stops operating, the first isolating switch group, the third isolating switch group and the fourth isolating switch group are closed, the second isolating switch group is disconnected, the user-side energy storage system is in a power supply state, and the photovoltaic power generation DC system and the user-side energy storage system simultaneously power the electrolyzer. When the user-side energy storage system finishes discharging, the first isolating switch group, the third isolating switch group and the fourth isolating switch group are disconnected, the user-side energy storage system is in a standby state, and the photovoltaic power generation DC system and the user-side energy storage system stop supplying power.

[0018] The beneficial effects of the present invention are: 1. The DC power output of photovoltaic power generation with higher capacity is directly used to power the electrolyzer, which improves the efficiency of photovoltaic power generation and provides an effective method for local consumption of photovoltaic power generation; 2. Effectively reduce the impact of the instability and intermittency of the photovoltaic power generation DC system on the working performance of the electrolyzer, and achieve high adaptability of the DC power output of the photovoltaic power generation to be directly applied to the power supply of the electrolyzer; 3. There is no need to change the existing power supply system configuration of the electrolytic cell. The power supply method can be implemented by simply adding a user-side energy storage system and an isolating switch group on the basis of the existing power supply system. This method is not only applicable to newly built aluminum smelters, but also to the upgrade and transformation of existing aluminum smelters. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the power supply system for the existing electrolyzer; Figure 2 The present invention is a schematic diagram of a power supply system for a method of supplying power to an electrolytic cell of an energy storage aluminum smelter for off-grid access and consumption of green electricity.

[0020] In the figure: 1. Photovoltaic power generation DC system; 1-1. Negative bus protection cabinet; 1-2. Positive bus protection cabinet; 2. Connecting bus; 3. DC bus; 4. Power supply rectifier system; 4-1. Distribution device; 4-2. Voltage regulating transformer; 4-3. Rectifier transformer; 4-4. Rectifier; 5. Electrolyzer; 6. User-side energy storage system; 6-1. First isolation module; 6-2. Charging module; 6-3. Energy storage module; 6-4. Discharging module; 6-5. Second isolation module; 6-6. Control and protection module; 7. First isolating switch group; 8. Second isolating switch group; 9. Third isolating switch group; 10. Fourth isolating switch group. DETAILED DESCRIPTION

[0021] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below in conjunction with the accompanying drawings through specific embodiments. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a clearer and more thorough understanding of the present invention and to be able to fully convey the scope of the present invention to those skilled in the art.

[0022] Figure 1 The figure shows an existing electrolytic cell power supply system. According to the requirements of the electrolytic cell series current and other requirements, the existing electrolytic cell power supply system usually has 7 to 10 sets of rectifier devices. Each set of rectifier devices is mainly composed of a distribution device 4-1, a voltage regulating transformer 4-2, a rectifier transformer 4-3 (a saturated inductor is provided to cooperate with the rectifier of the diode element for voltage regulation), a rectifier 4-4 (the rectifier element is usually a diode), a DC bus 3, etc., which converts the AC power on the grid side into DC power to provide DC power for the electrolytic aluminum plant.

[0023] like Figure 2 As shown, the present invention provides an energy storage type aluminum electrolytic cell power supply system for green electricity off-grid access and consumption, including a photovoltaic power generation DC system 1, a power supply rectifier system 4 and an electrolytic cell 5 connected through a busbar, and also includes a user-side energy storage system 6 connected to the busbar, wherein the access end of the user-side energy storage system 6 is connected to the photovoltaic power generation DC system 1, and the output end is connected to the power supply rectifier system 4; The busbar is provided with a first isolating switch group 7 and a fourth isolating switch group 10. The first isolating switch group 7 is provided between the photovoltaic power generation DC system 1 and the user-side energy storage system 6. The fourth isolating switch group 10 is provided between the user-side energy storage system 6 and the power supply rectifier system 4. The access end of the user-side energy storage system 6 is provided with a second isolating switch group, and the output end is provided with a third isolating switch group 9.

[0024] By providing the user-side energy storage system 6 and the first to fourth isolating switch groups 10, the user-side energy storage system 6 can be used to start supplying power when the rate of change of the output current of the photovoltaic power generation DC system 1 exceeds the acceptance range of the electrolytic cell 5, thereby solving the problem that the electrolytic cell 5 is difficult to work stably in the original electrolytic cell power supply system when the amplitude of the photovoltaic power generation output DC exceeds 5% of the electrolytic series current, and achieving the high adaptability of the electrolytic cell power supply system of the aluminum electrolytic plant when the photovoltaic power generation outputs a higher capacity DC, thereby ensuring the stability of the operation of the electrolytic cell 5.

[0025] Specifically, the user-side energy storage system 6 includes a charging module 6-2, a discharging module 6-4, an isolation module, a control and protection module 6-6 and an energy storage module 6-3. The charging module 6-2 is used to input a part of the DC power emitted by the photovoltaic power generation DC system 1 into the energy storage module 6-3 for charging; the discharging module 6-4 is used to output the electric energy of the energy storage module 6-3; the control and protection module 6-6 is used to control the output voltage of the user-side energy storage system 6 to be consistent with the voltage required by the electrolytic cell 5; there are two isolation modules, and the isolation modules are used to isolate the reverse flow of current. The two isolation modules are respectively a first isolation module 6-1 and a second isolation module 6-5. The first isolation module 6-1 is arranged at the access end of the user-side energy storage system 6, and the second isolation module 6-5 is arranged at the output end of the user-side energy storage system 6.

[0026] An isolation module is provided to prevent the occurrence of a fault in which the current flows in the reverse direction.

[0027] Specifically, the busbar includes a connecting busbar 2 and a DC busbar 3. The photovoltaic power generation DC system 1 is connected to the user-side energy storage system 6 through the connecting busbar 2. The power supply rectifier system 4 is connected to the electrolytic cell 5 through the DC busbar 3. The connecting busbar 2 is connected to the DC busbar 3 through the fourth isolating switch group 10.

[0028] More specifically, the photovoltaic power generation DC system 1 includes a positive bus protection cabinet 1-2 and a negative bus protection cabinet 1-1, and the starting end of the photovoltaic power generation DC system 1 connected to the connection bus 2 is the output end of the positive and negative bus protection cabinets 1-1; the access end of the electrolytic cell 5 is the positive and negative DC bus 3; The output ends of the positive bus protection cabinet 1 - 2 and the negative bus protection cabinet 1 - 1 are connected to the connecting bus 2 through the first isolating switch group 7 , and are connected to the DC bus 3 through the fourth isolating switch group 10 .

[0029] The user-side energy storage system 6 includes a first isolation module 6-1, a charging module 6-2, an energy storage module 6-3, a discharge module 6-4 and a second isolation module 6-5 from the access end to the output end, and all of the above modules are connected to the control and protection module 6-6.

[0030] The present invention also provides a method for supplying power to an energy storage type aluminum electrolytic cell with off-grid access and consumption of green electricity, which adopts an energy storage type aluminum electrolytic cell power supply system with off-grid access and consumption of green electricity, and controls the on and off of the first isolating switch group 7 to the fourth isolating switch group 10 according to the output current of the photovoltaic power generation DC system 1, thereby switching the operating state of the user-side energy storage system 6; When the rate of change of the output current of the photovoltaic power generation DC system 1 exceeds the acceptance range of the electrolytic cell 5, the first isolating switch group, the third isolating switch group 9 and the fourth isolating switch group 10 are closed, the second isolating switch group 8 is opened, and the user-side energy storage system 6 is in a power supply state.

[0031] By designing a power supply method, the problem that the electrolytic cell 5 of the original electrolytic cell power supply system is difficult to work stably when the amplitude of the direct current output by photovoltaic power generation exceeds 5% of the electrolytic series current is solved. Combined with the opening and closing control of the isolating switch group in the corresponding situation and the state control of the user-side energy storage system 6, the electrolytic aluminum plant electrolytic cell power supply system is highly adaptable when the photovoltaic power generation outputs a higher capacity direct current, thereby ensuring the stability of the operation of the electrolytic cell 5.

[0032] Specifically, when the current value output by the photovoltaic power generation DC system 1 is higher than the current value required by the electrolytic cell 5, the first isolating switch group 7, the second isolating switch group 8 and the fourth isolating switch group 10 are closed, and the third isolating switch group 9 is disconnected, so that the photovoltaic power generation DC system 1 can supply power to the electrolytic cell 5 normally while transmitting excess electric energy to the user-side energy storage system 6, and the user-side energy storage system 6 is in an energy storage state.

[0033] Specifically, when the current value output by the photovoltaic power generation DC system 1 is within the current value range required by the electrolytic cell 5, the first isolating switch group 7 and the fourth isolating switch group 10 are closed, and the second isolating switch group 8 and the third isolating switch group 9 are disconnected, so that the photovoltaic power generation DC system 1 can supply power to the electrolytic cell 5 normally, and the user-side energy storage system 6 is in standby mode.

[0034] Specifically, when the current value output by the photovoltaic power generation DC system 1 is less than the current value required by the electrolytic cell 5, and the rate of change of the output current of the photovoltaic power generation DC system 1 is within the acceptable range of the electrolytic cell 5, the first isolating switch group 7 and the fourth isolating switch group 10 are closed, and the second isolating switch group 8 and the third isolating switch group 9 are disconnected. The photovoltaic power generation DC system 1 supplies power to the electrolytic cell 5 normally, and the user-side energy storage system 6 is in standby mode.

[0035] Specifically, when the current value output by the photovoltaic power generation DC system 1 is less than the current value required by the electrolyzer 5, and the rate of change of the output current of the photovoltaic power generation DC system 1 exceeds the acceptable range of the electrolyzer 5, the first isolating switch group 7, the third isolating switch group 9 and the fourth isolating switch group 10 are closed, the second isolating switch group 8 is disconnected, the user-side energy storage system 6 is in the power supply state, and the photovoltaic power generation DC system 1 and the user-side energy storage system 6 simultaneously supply power to the electrolyzer 5. Ensure that the rate of change of the current supplied to the electrolyzer 5 is within the acceptable range of the electrolyzer 5, thereby ensuring the stable operation of the electrolyzer 5.

[0036] Specifically, when the photovoltaic power generation DC system 1 stops operating and the output current value is 0A, the third isolating switch group 9 and the fourth isolating switch group 10 are closed, the first isolating switch group 7 and the second isolating switch group 8 are disconnected, the photovoltaic power generation DC system 1 stops supplying power to the electrolyzer 5, and the user-side energy storage system 6 is in a power supply state to supply power to the electrolyzer 5. Ensure that the current change rate supplied to the electrolyzer 5 is within the acceptable range of the electrolyzer 5, thereby ensuring the stable operation of the electrolyzer 5.

[0037] Specifically, when the power supply rectifier system 4 stops operating, the first isolating switch group 7, the third isolating switch group 9 and the fourth isolating switch group 10 are closed, the second isolating switch group 8 is disconnected, the user-side energy storage system 6 is in a power supply state, and the photovoltaic power generation DC system 1 and the user-side energy storage system 6 simultaneously supply power to the electrolyzer 5. When the user-side energy storage system 6 finishes discharging, the first isolating switch group 7, the third isolating switch group 9 and the fourth isolating switch group 10 are disconnected, the user-side energy storage system 6 is in a standby state, and the photovoltaic power generation DC system 1 and the user-side energy storage system 6 stop supplying power.

[0038] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A green electricity off-grid access and energy storage type aluminum electrolytic cell power supply system, comprising a photovoltaic power generation DC system (1), a power supply rectification system (4) and an electrolytic cell (5) connected via a busbar, characterized in that: It also includes a user-side energy storage system (6) connected to the busbar, wherein the access end of the user-side energy storage system (6) is connected to the photovoltaic power generation DC system (1), and the output end is connected to the power supply rectification system (4); The busbar is provided with a first isolating switch group (7) and a fourth isolating switch group (10); the first isolating switch group (7) is provided between the photovoltaic power generation DC system (1) and the user-side energy storage system (6); the fourth isolating switch group (10) is provided between the user-side energy storage system (6) and the power supply rectifier system (4); the access end of the user-side energy storage system (6) is provided with a second isolating switch group, and the output end is provided with a third isolating switch group (9).

2. The energy storage type aluminum electrolytic cell power supply system for green electricity off-grid access and consumption as claimed in claim 1, characterized in that: The user-side energy storage system (6) comprises a charging module (6-2), a discharging module (6-4), an isolation module, a control and protection module (6-6) and an energy storage module (6-3); the charging module (6-2) is used to input a portion of the direct current generated by the photovoltaic power generation direct current system (1) into the energy storage module (6-3) for charging; the discharging module (6-4) is used to output the electric energy of the energy storage module (6-3); the control and protection module (6-6) is used to control the output voltage of the user-side energy storage system (6) to be consistent with the voltage required by the electrolytic cell (5); there are two isolation modules, each of which is used to isolate the reverse flow of current, and the two isolation modules are respectively a first isolation module (6-1) and a second isolation module (6-5); the first isolation module (6-1) is arranged at the access end of the user-side energy storage system (6), and the second isolation module (6-5) is arranged at the output end of the user-side energy storage system (6).

3. The energy storage type electrolytic cell power supply system for green electricity off-grid access and consumption according to claim 1 is characterized by: The busbar comprises a connecting busbar (2) and a DC busbar (3); the photovoltaic power generation DC system (1) is connected to a user-side energy storage system (6) via the connecting busbar (2); the power supply rectifier system (4) is connected to an electrolytic cell (5) via the DC busbar (3); and the connecting busbar (2) is connected to the DC busbar (3) via a fourth isolating switch group (10).

4. A method for supplying power to an energy storage type aluminum electrolytic cell with off-grid access for green electricity, using the energy storage type aluminum electrolytic cell power supply system with off-grid access for green electricity as claimed in any one of claims 1 to 3, characterized in that: Controlling the on and off of the first isolating switch group (7) to the fourth isolating switch group (10) according to the output current of the photovoltaic power generation DC system (1), thereby switching the operating state of the user-side energy storage system (6); When the rate of change of the output current of the photovoltaic power generation DC system (1) exceeds the acceptance range of the electrolytic cell (5), the first isolating switch group (7), the third isolating switch group (9) and the fourth isolating switch group (10) are closed, the second isolating switch group (8) is opened, and the user-side energy storage system (6) is in a power supply state.

5. The method for supplying power to an energy storage type aluminum electrolytic cell with off-grid access for green electricity consumption as claimed in claim 1, characterized in that: When the current value output by the photovoltaic power generation DC system (1) is higher than the current value required by the electrolytic cell (5), the first isolating switch group (7), the second isolating switch group (8) and the fourth isolating switch group (10) are closed, and the third isolating switch group (9) is opened, so that the photovoltaic power generation DC system (1) supplies power to the electrolytic cell (5) normally while transmitting excess electric energy to the user-side energy storage system (6), and the user-side energy storage system (6) is in an energy storage state.

6. The energy storage type aluminum electrolytic cell power supply method for green electricity off-grid access and consumption as claimed in claim 1, characterized in that: When the current value output by the photovoltaic power generation DC system (1) is within the current value range required by the electrolytic cell (5), the first isolating switch group (7) and the fourth isolating switch group (10) are closed, and the second isolating switch group (8) and the third isolating switch group (9) are opened, so that the photovoltaic power generation DC system (1) supplies power to the electrolytic cell (5) normally, and the user-side energy storage system (6) is in a standby state.

7. The method for supplying power to an energy storage type aluminum electrolytic cell with off-grid access for green electricity consumption as claimed in claim 1, characterized in that: When the current value output by the photovoltaic power generation DC system (1) is less than the current value required by the electrolytic cell (5), and the rate of change of the output current of the photovoltaic power generation DC system (1) is within the acceptable range of the electrolytic cell (5), the first isolating switch group (7) and the fourth isolating switch group (10) are closed, the second isolating switch group (8) and the third isolating switch group (9) are opened, the photovoltaic power generation DC system (1) supplies power to the electrolytic cell (5) normally, and the user-side energy storage system (6) is in a standby state.

8. The energy storage type aluminum electrolytic cell power supply method for green electricity off-grid access and consumption as claimed in claim 1, characterized in that: When the current value output by the photovoltaic power generation DC system (1) is less than the current value required by the electrolytic cell (5), and the rate of change of the output current of the photovoltaic power generation DC system (1) exceeds the acceptable range of the electrolytic cell (5), the first isolating switch group (7), the third isolating switch group (9) and the fourth isolating switch group (10) are closed, the second isolating switch group (8) is opened, the user-side energy storage system (6) is in a power supply state, and the photovoltaic power generation DC system (1) and the user-side energy storage system (6) simultaneously supply power to the electrolytic cell (5).

9. The energy storage type aluminum electrolytic cell power supply method for green electricity off-grid access and consumption as claimed in claim 1, characterized in that: When the photovoltaic power generation DC system (1) stops operating and the output current value is 0A, the third isolating switch group (9) and the fourth isolating switch group (10) are closed, the first isolating switch group (7) and the second isolating switch group (8) are disconnected, the photovoltaic power generation DC system (1) stops supplying power to the electrolyzer (5), and the user-side energy storage system (6) is in a power supply state to supply power to the electrolyzer (5).

10. The energy storage type aluminum electrolytic cell power supply method for green electricity off-grid access and consumption as claimed in claim 1, characterized in that: When the power supply rectifier system (4) stops operating, the first isolating switch group (7), the third isolating switch group (9) and the fourth isolating switch group (10) are closed, the second isolating switch group (8) is disconnected, the user-side energy storage system (6) is in a power supply state, and the photovoltaic power generation DC system (1) and the user-side energy storage system (6) simultaneously supply power to the electrolyzer (5); when the user-side energy storage system (6) finishes discharging, the first isolating switch group (7), the third isolating switch group (9) and the fourth isolating switch group (10) are disconnected, the user-side energy storage system (6) is in a standby state, and the photovoltaic power generation DC system (1) and the user-side energy storage system (6) stop supplying power.

Images