Multi-energy comprehensive power generation system and thermoelectric cooperative control method

Abstract

The invention aims to provide a multi-energy comprehensive power generation system and a thermoelectric cooperative control method, and belongs to the field of hybrid energy storage power generation. Comprising a photovoltaic power generation subsystem, an energy storage subsystem, a hydrogen production subsystem, a hydrogen storage / desorption subsystem, a fuel cell subsystem, a thermoelectric power generation subsystem, a direct-current power grid and a load, the photovoltaic power generation subsystem, the hydrogen production subsystem, the fuel cell subsystem, the thermoelectric power generation subsystem and the energy storage subsystem are connected to a direct-current power grid; hydrogen prepared by the hydrogen production subsystem is respectively stored to the hydrogen storage and desorption subsystem through hydrogen pipeline connection and is conveyed to the fuel cell subsystem; the hydrogen storage and desorption subsystem supplies hydrogen to the fuel cell subsystem; the thermoelectric power generation subsystem generates power by using the temperature difference between the high-temperature waste gas of the fuel cell subsystem and the environment; the DC power grid output electric energy meets the power demand of the load. According to the technical scheme provided by the invention, each subsystem is coordinated and controlled, and the advantages of greenness, cleanness and wide power coverage range of the comprehensive energy system are fully exerted.

Description

Technical Field

[0001] The present invention relates to an energy storage power generation device and method, specifically a hybrid energy storage power generation device and method. Background Technology

[0002] Electricity is one of the most important energy sources for modern human life, crucial to people's production and daily lives. Although clean power generation methods such as wind power and photovoltaics have made some progress, thermal power generation remains the mainstream method of power generation. Therefore, finding new clean energy alternatives to traditional fossil fuels is a goal of energy development for countries around the world.

[0003] Clean energy sources, represented by photovoltaics and wind power, have been applied to some extent and have continued to develop over the past few decades. However, new clean energy sources still face some challenges in application. Hydrogen energy is highly efficient and clean, but it also presents challenges in transportation, storage, and safety. Photovoltaic and wind power are characterized by uncertainty and randomness, and are therefore often referred to as "curtailed solar power" or "curtailed wind power." Therefore, combining multiple energy forms to leverage their strengths and compensate for their weaknesses can maximize the effectiveness of each power generation device. For example, using the electricity generated by photovoltaics and wind power to provide the power needed for hydrogen production through water electrolysis, while storing the produced hydrogen for future use in fuel cells, is an effective method for a comprehensive energy power generation system that integrates photovoltaics, wind power, hydrogen production, and hydrogen utilization.

[0004] In the context of integrated energy generation systems, the coordinated operation of various subsystems is key to achieving high efficiency and cleanliness. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-energy integrated power generation system and a thermoelectric synergistic control method that can realize the integrated production, storage and utilization of photovoltaic-electrolysis water hydrogen production-hydrogen storage-fuel cells and photovoltaic-energy storage.

[0006] The objective of this invention is achieved as follows: This invention discloses a multi-energy integrated power generation system, characterized by comprising a photovoltaic power generation system, an energy storage subsystem, a hydrogen production subsystem, a hydrogen storage / discharge subsystem, a fuel cell subsystem, a thermoelectric power generation system, a DC power grid, and a load. The photovoltaic power generation system, hydrogen production subsystem, fuel cell subsystem, thermoelectric power generation system, and energy storage subsystem are connected to the DC power grid. Hydrogen produced by the hydrogen production subsystem is stored in the hydrogen storage / discharge subsystem and transported to the fuel cell subsystem via hydrogen pipelines. The hydrogen storage / discharge subsystem supplies hydrogen to the fuel cell subsystem. The thermoelectric power generation system generates electricity using the temperature difference between the high-temperature exhaust gas from the fuel cell subsystem and the ambient temperature. The DC power grid outputs electrical energy to meet the power requirements of the load.

[0007] The multi-energy integrated power generation system of the present invention may further include: 1. The fuel cell subsystem is a solid oxide fuel cell; the energy storage subsystem is a lithium iron phosphate battery or lithium-ion battery and a supercapacitor load energy storage system; the hydrogen production subsystem is hydrogen production by water electrolysis.

[0008] This invention discloses a multi-energy integrated power generation and thermoelectric coordinated control method, characterized by employing the aforementioned multi-energy integrated power generation system, comprising the following steps: (1) Obtain the power demand of the external load; (2) Based on the required power, the hydrogen production subsystem produces the corresponding hydrogen gas while ensuring that the electrolyzer is within the preset operating temperature range; (3) Based on the required power, the hydrogen production subsystem provides a fixed amount of hydrogen to the fuel cell subsystem, and the excess hydrogen is stored in the hydrogen storage / discharge subsystem, while ensuring that the hydrogen storage status of the system is kept within the normal range. (4) Control the flow rate of hydrogen and air into the fuel cell subsystem according to the required power, while ensuring that the fuel cell stack is within the preset operating temperature range; at this time, the fuel cell generates electrical energy under electrochemical action. (5) Control the amount of exhaust gas fed into the thermoelectric generator system according to the required power, and use the temperature difference between the high temperature exhaust gas of the fuel cell and the ambient temperature to generate electricity, while controlling the thermoelectric generator system to be within the preset operating temperature range. (6) If the electrical energy generated by the fuel cell subsystem and the thermoelectric power generation system cannot meet the required power, the energy storage system shall make up for the shortfall; if the electrical energy generated by the fuel cell subsystem and the thermoelectric power generation system is higher than the required power, the excess shall be stored in the energy storage system. (7) The photovoltaic subsystem provides electricity to the hydrogen production subsystem. If the generated electricity is high, the excess is stored in the energy storage system. (8) During operation, the hydrogen production subsystem, fuel cell subsystem and thermoelectric power generation system are all within the preset operating temperature range and simultaneously meet the load power requirements, thereby realizing thermoelectric coordinated control of the integrated energy power generation system.

[0009] The advantages of this invention are: 1. The system of this invention includes a photovoltaic power generation system, an energy storage subsystem, a hydrogen production subsystem, a hydrogen storage / discharge subsystem, a fuel cell subsystem, a thermoelectric power generation system, a DC power grid, a DC / DC converter, and a control subsystem. It boasts advantages such as zero carbon emissions and a wide power coverage range. The thermoelectric generator, photovoltaic subsystem, and energy storage subsystem expand the system's power output range, meeting the demands of different power loads. The thermoelectric generator recovers and utilizes waste heat from the fuel cell exhaust gas, improving the system's energy utilization efficiency.

[0010] 2. The introduction of energy storage batteries plays a role in peak shaving and valley filling, absorbing excess electrical energy from photovoltaic power generation systems, fuel cells, and thermoelectric power generation systems. Simultaneously, it possesses a certain power output capability, supplementing the insufficient power output of fuel cells. When load power demand changes frequently, energy storage batteries can quickly respond to changes in demand, thereby avoiding frequent fluctuations in fuel cell output power and improving the system's output response speed. Energy storage batteries meet the high-frequency portion of the load power, reducing fuel cell power fluctuations, thus extending fuel cell lifespan and improving fuel cell efficiency. Furthermore, the combination of energy storage batteries and fuel cells, through optimized power distribution, can optimize the fuel cell's operating point, allowing it to operate in its high-efficiency range, thereby improving the overall efficiency of the power grid and meeting the grid's electricity demand.

[0011] 3. The energy storage subsystem has the advantage of fast response, compensating for the slow response of the fuel cell and hydrogen production subsystems. During the fuel cell startup phase, the energy storage subsystem is primarily responsible for meeting the system's power requirements. When hydrogen production is needed, the energy storage subsystem can quickly provide electrical energy to the hydrogen production subsystem.

[0012] 4. A multi-energy integrated power generation system realizes the integrated production, storage, and utilization of hydrogen. The water electrolysis hydrogen production subsystem and the photovoltaic power generation system achieve zero-emission green hydrogen production. The photovoltaic subsystem converts solar energy into electrical energy to power the hydrogen production subsystem. The hydrogen production subsystem generates hydrogen through water electrolysis. The hydrogen is stored in the hydrogen storage / discharge subsystem and supplied to fuel cells. The hydrogen production subsystem absorbs electrical energy output from the photovoltaic power generation system, overcoming the instability and uncertainty of photovoltaic power generation.

[0013] 5. The proposed multi-energy integrated power generation system integrates photovoltaic, hybrid energy storage, and fuel cell clean energy, and has the advantages of zero carbon emissions and green sustainability. Attached Figure Description

[0014] Figure 1 This is a structural view of the power generation system of the present invention; Figure 2 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0015] The invention will now be described in more detail with reference to the accompanying drawings: Combination Figure 1-2This invention discloses a multi-energy integrated power generation system comprising a photovoltaic power generation system 1, a DC / DC converter 2, a hydrogen production subsystem 3, a hydrogen storage / discharge subsystem 4, a fuel cell subsystem 5, a DC / DC converter 6, a thermoelectric power generation system 7, a DC / DC converter 8, an energy storage subsystem 9, a load 10, and a DC power grid 11. The connections are as follows: the photovoltaic power generation system is connected to the DC power grid 11 via DC / DC converter 1; the hydrogen production subsystem 2 is connected to the DC power grid 11; the fuel cell subsystem 5 is connected to the DC power grid 11 via DC / DC converter 6; the thermoelectric power generation system 7 is connected to the DC power grid 11 via DC / DC converter 8; the energy storage subsystem 9 is directly connected to the DC power grid 11; the hydrogen produced by the hydrogen production subsystem 2 is stored in the hydrogen storage / discharge subsystem 3 and transported to the fuel cell subsystem 5 via hydrogen pipelines; the hydrogen storage / discharge subsystem 3 supplies hydrogen to the fuel cell subsystem 5; the thermoelectric power generation system 7 generates electricity using the temperature difference between the high-temperature exhaust gas from the fuel cell subsystem 5 and the ambient temperature. The DC power grid 11 outputs electrical energy to meet the power requirements of the load 10.

[0016] Fuel cell subsystem 5 is preferably a solid oxide fuel cell, and energy storage subsystem 9 is preferably a lithium iron phosphate battery with high power density and small size and weight, or a lithium-ion battery and supercapacitor load energy storage system. Hydrogen production subsystem 3 is preferably produced by water electrolysis. The hydrogen produced by the hydrogen production subsystem is supplied to the fuel cell to generate electricity, or stored in the hydrogen storage / discharge subsystem; when the hydrogen production subsystem is not working, the hydrogen storage / discharge subsystem has the ability to independently supply the hydrogen required by the fuel cell.

[0017] Thermoelectric power generation systems utilize the temperature difference between the high-temperature exhaust gas from fuel cells and the ambient environment to generate electricity. The amount of exhaust gas supplied to the thermoelectric power generation system is adjusted according to the power demand. The exhaust gas flow rate into the thermoelectric power generation system can be controlled by a regulating valve; when the load demand is high, the exhaust gas flow rate is increased, and vice versa. The system is kept operating within its normal temperature range; when the temperature is high, the exhaust gas flow rate is reduced.

[0018] The energy storage subsystem plays a role in peak shaving and valley filling, and during the slow start-up of fuel cells, the energy storage battery can assume the main power output role. Therefore, in the actual operation of a practical integrated energy system, it is necessary to control the charging and discharging of the system according to the state of charge of the energy storage system.

[0019] The energy storage subsystem employs lithium-ion batteries, supercapacitors, or a hybrid of both, resulting in a strong transient response. When external power surges, the subsystem can adapt rapidly, preventing frequent fluctuations in fuel cell output power. It also features peak shaving and valley filling capabilities, possessing significant capacity and output power. This allows it to compensate for insufficient output from fuel cells and thermoelectric systems during periods of high power demand, while also absorbing curtailed solar power. Simultaneously, it meets low-load power requirements, mitigating the slow start-up characteristic of solid oxide fuel cells. The energy source for the subsystem comprises solar power, fuel cell subsystems, and thermoelectric systems. The thermoelectric coordinated control strategy requires maintaining a high state of charge (SOC) for the energy storage subsystem.

[0020] The photovoltaic subsystem is highly unpredictable and prone to power curtailment. Therefore, the energy generated by the photovoltaic subsystem is consumed by the energy storage and hydrogen production subsystems. When the state of charge (SOC) of the hydrogen storage / discharge subsystem is low, the photovoltaic subsystem employs maximum power control to provide power to the hydrogen production subsystem. When the SOC of the hydrogen storage / discharge subsystem is at a high level, the photovoltaic subsystem uses a constant power output mode.

[0021] Combination Figure 2 The thermoelectric coordinated control method of the multi-energy integrated power generation system of the present invention is based on Figure 2 The process can be carried out in the following steps: (1) Obtain the external load demand power of the multi-energy integrated power generation system.

[0022] (2) Based on the required power, the hydrogen production subsystem prepares an appropriate amount of hydrogen gas while ensuring that the electrolyzer is within the preset operating temperature range.

[0023] (3) Based on the required power, the hydrogen production subsystem provides a fixed amount of hydrogen to the fuel cell subsystem, and the excess hydrogen is stored in the hydrogen storage / discharge subsystem. At the same time, the hydrogen storage status of the system is kept within the normal range.

[0024] (4) Control the flow rate of hydrogen and air into the fuel cell stack according to the required power, while ensuring that the fuel cell stack is within the preset operating temperature range. At this time, the fuel cell generates electrical energy under electrochemical action.

[0025] (5) Control the amount of exhaust gas supplied to the thermoelectric generator system according to the required power, and generate electricity by utilizing the temperature difference between the high-temperature exhaust gas of the fuel cell and the ambient temperature. At the same time, the thermoelectric generator system should be controlled within the preset operating temperature range.

[0026] (6) If the electrical energy generated by the fuel cell subsystem and the thermoelectric power generation system cannot meet the power demand, the energy storage system will make up for the shortfall. If the electrical energy generated by the fuel cell subsystem and the thermoelectric power generation system exceeds the power demand, the excess will be stored in the energy storage system.

[0027] (7) The photovoltaic subsystem mainly provides electricity to the hydrogen production subsystem. If the generated electricity is high, the excess is stored in the energy storage system.

[0028] (8) During operation, the hydrogen production subsystem, fuel cell subsystem and thermoelectric power generation system are all within the preset operating temperature range and simultaneously meet the load power requirements, thereby realizing thermoelectric coordinated control of the integrated energy power generation system.

[0029] As described above, this invention proposes a multi-energy integrated power generation system and a thermoelectric synergistic control method. The multi-energy integrated power generation system boasts advantages such as zero emissions and a wide power coverage range, while effectively recovering and utilizing waste heat to improve the system's energy utilization efficiency. Simultaneously, the energy storage subsystem not only possesses the advantage of rapid response but also compensates for the slow response of the fuel cell and hydrogen production subsystems, further optimizing power distribution among the subsystems and ensuring their operation in the high-efficiency zone, thereby improving the power generation efficiency of the integrated power generation system. Furthermore, the water electrolysis hydrogen production subsystem and the photovoltaic power generation system achieve zero-emission green hydrogen production. The photovoltaic subsystem converts solar energy into electrical energy to power the hydrogen production subsystem. The hydrogen production subsystem generates hydrogen through water electrolysis. The hydrogen is stored in the hydrogen storage / release subsystem and supplied to the fuel cell. The hydrogen production subsystem absorbs electrical energy output from the photovoltaic power generation system, overcoming the instability and uncertainty of photovoltaic power generation.

Claims

1. A multi-energy integrated power generation system, characterized by: The system includes a photovoltaic power generation system, an energy storage subsystem, a hydrogen production subsystem, a hydrogen storage / discharge subsystem, a fuel cell subsystem, a thermoelectric power generation system, a DC power grid, and a load. The photovoltaic power generation system, hydrogen production subsystem, fuel cell subsystem, thermoelectric power generation system, and energy storage subsystem are connected to the DC power grid. Hydrogen produced by the hydrogen production subsystem is stored in the hydrogen storage / discharge subsystem and transported to the fuel cell subsystem via hydrogen pipelines. The hydrogen storage / discharge subsystem supplies hydrogen to the fuel cell subsystem. The thermoelectric power generation system generates electricity using the temperature difference between the high-temperature exhaust gas from the fuel cell subsystem and the ambient temperature. The DC power grid outputs electrical energy to meet the power requirements of the load.

2. The multi-energy integrated power generation system according to claim 1, characterized in that: The fuel cell subsystem is a solid oxide fuel cell; the energy storage subsystem is a lithium iron phosphate battery or lithium-ion battery and a supercapacitor load energy storage system; and the hydrogen production subsystem is hydrogen production by water electrolysis.

3. A multi-energy integrated power generation and thermoelectric coordinated control method, characterized by: The multi-energy integrated power generation system as described in claim 1 includes the following steps: (1) Obtain the power demand of the external load; (2) Based on the required power, the hydrogen production subsystem produces the corresponding hydrogen gas while ensuring that the electrolyzer is within the preset operating temperature range; (3) Based on the required power, the hydrogen production subsystem provides a fixed amount of hydrogen to the fuel cell subsystem, and the excess hydrogen is stored in the hydrogen storage / discharge subsystem, while ensuring that the hydrogen storage status of the system is kept within the normal range. (4) Control the flow rate of hydrogen and air into the fuel cell subsystem according to the required power, while ensuring that the fuel cell stack is within the preset operating temperature range; at this time, the fuel cell generates electrical energy under electrochemical action. (5) Control the amount of exhaust gas fed into the thermoelectric generator system according to the required power, and use the temperature difference between the high temperature exhaust gas of the fuel cell and the ambient temperature to generate electricity, while controlling the thermoelectric generator system to be within the preset operating temperature range. (6) If the electrical energy generated by the fuel cell subsystem and the thermoelectric power generation system cannot meet the required power, the energy storage system shall make up for the shortfall; if the electrical energy generated by the fuel cell subsystem and the thermoelectric power generation system is higher than the required power, the excess shall be stored in the energy storage system. (7) The photovoltaic subsystem provides electricity to the hydrogen production subsystem. If the generated electricity is high, the excess is stored in the energy storage system. (8) During operation, the hydrogen production subsystem, fuel cell subsystem and thermoelectric power generation system are all within the preset operating temperature range and simultaneously meet the load power requirements, thereby realizing thermoelectric coordinated control of the integrated energy power generation system.

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