Thermal power plant multi-auxiliary-machine energy supply system based on new energy and compressed air energy storage cooperative driving and energy efficiency improving method of thermal power plant multi-auxiliary-machine energy supply system

Abstract

The invention relates to the field of energy system cooperative control, and discloses a thermal power plant multi-auxiliary machine energy supply system and method based on new energy and compressed air energy storage cooperative driving. A new energy power generation unit directly provides power for electric auxiliary machines, and a compressed air energy storage device is assisted as a buffer link; excess energy can be absorbed when new energy is excessive, compensation power is provided when the new energy is insufficient, and excessive dependence of an electric auxiliary engine on steam extraction of a main engine and power supply of a power grid is avoided. The central control system formulates a perfect control strategy for the cooperative energy supply structure, and the control strategy comprises functional modules for prediction of new energy output, real-time detection of power grid frequency, dynamic matching control of the load of the electric auxiliary machine and the like, so that the electric auxiliary machine always obtains stable and efficient power support.

Description

Technical Field

[0001] This invention relates to the field of coordinated control of energy systems, specifically a multi-auxiliary power plant energy supply system based on the coordinated drive of new energy sources and compressed air energy storage, and a method for improving its energy efficiency. Background Technology

[0002] Traditional thermal power plants typically power their main electric auxiliary equipment (such as feedwater pumps, coal mills, induced draft fans, and desulfurization slurry circulation pumps) by drawing steam from the main turbine or by supplying power to the plant's auxiliary power grid. In steam-driven mode, the operation of these auxiliary equipment consumes a significant amount of steam that could otherwise be used for power generation, leading to a decrease in the main turbine's thermal efficiency. Furthermore, the response speed of steam-driven electric auxiliary equipment to load changes is slow, making it difficult to adapt to rapid fluctuations in power load. In grid-supply mode, the electric auxiliary equipment draws power directly from the thermal power unit's generator or the public grid. Changes in the load on these auxiliary equipment affect the unit's output distribution, and energy utilization efficiency is relatively low.

[0003] In recent years, with the development of power electronics technology and renewable energy, the electric auxiliary equipment in thermal power plants has gradually undergone electrification. For example, turbine-driven feedwater pumps have been replaced with electric motor-driven pumps, and electric motors have been used to drive coal mills, fans, and pumps. This electrification of electric auxiliary equipment drives has improved the flexibility and response speed of unit regulation. However, currently, the electricity required by electric auxiliary equipment still largely relies on the power generation of the thermal power unit itself or external power grid supply, and coordinated utilization with new energy power generation systems has not yet been achieved. When the output of new energy sources such as wind power and photovoltaics fluctuates, the electric auxiliary equipment lacks corresponding optimized control methods to fully utilize the surplus clean electricity during off-peak hours, resulting in the need to improve the overall energy efficiency and dynamic performance of the electric auxiliary equipment power supply system. Summary of the Invention

[0004] The purpose of this invention is to overcome the problem that the current electric auxiliary machines mostly rely on the power generation supply of the thermal power unit itself or the power supply of the external power grid, and have not yet achieved coordinated utilization with the new energy power generation system. The invention provides a multi-auxiliary machine power supply system for thermal power plants based on the coordinated drive of new energy and compressed air energy storage, and its energy efficiency improvement method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a multi-auxiliary power supply system for thermal power plants based on the synergistic drive of new energy and compressed air energy storage, including a new energy power supply system, a compressed air energy storage system, several electric auxiliary machines and a central control system. The new energy power supply system is used to provide power to the electric auxiliary equipment of thermal power plants and to send the excess energy into the compressed air energy storage system to store energy; Compressed air energy storage systems are used to store excess energy and release it to power electric auxiliary machines when energy is insufficient. The electric auxiliary machine obtains the required electrical energy by being driven by an electric motor and connected to the electric auxiliary machine power supply bus. The central control system is used to monitor the power generation of new energy sources, the status of energy storage, and the load demand of electric auxiliary machines. Based on the grid frequency signal and power prediction information, it coordinates and controls the charging and discharging of the new energy power supply system and the compressed air energy storage system. During the day, it prioritizes the use of photovoltaic / wind power to drive the electric auxiliary machines and charge the compressed air energy storage system. At night or when the output of new energy sources is insufficient, it releases compressed air to expand and generate electricity to power the electric auxiliary machines.

[0006] A further improvement of the present invention is that the central control system includes: The power forecasting module is used to predict the power output of photovoltaic and wind power generation devices and estimate the load demand of each electric auxiliary machine based on meteorological and historical data. The frequency detection module is used to monitor the grid frequency deviation in real time and obtain the operating status information of thermal power units; The load matching control module is used to optimize the power distribution strategy between the new energy power supply system and the compressed air energy storage system based on prediction and detection results, formulate the power supply plan for electric auxiliary machines in advance, and adjust the power distribution of new energy and the charging and discharging power of energy storage in real time when the actual output of new energy does not match the prediction or when an abnormal grid frequency is detected.

[0007] A further improvement of the present invention is that the compressed air energy storage system includes an electric compressor, an air storage device, and an expansion power generation device. The electric compressor is connected to the power supply bus of the electric auxiliary machine and is controlled by the central control system. When there is excess power from new energy generation, it starts to compress air into the air storage tank or underground cavity for storage. At the same time, it recovers and stores the heat energy generated during the compression process through a heat storage device. Under the control of the central control system, the compressed air energy storage system releases the stored high-pressure air to generate electricity during peak electricity demand or when the output of new energy sources decreases. It also uses the heat energy provided by the thermal storage device to reheat the expanded air to improve the power generation efficiency. Its output power is connected to the power supply bus of the electric auxiliary machine to power the electric auxiliary machine equipment.

[0008] A further improvement of the present invention is that the electric auxiliary machine is connected to a unified electric auxiliary machine power supply bus via a frequency converter drive device, and the electric auxiliary machine power supply bus is simultaneously connected to the output end of the new energy power supply system and the power generation output end of the compressed air energy storage system. The central control system adjusts the speed and power of each electric auxiliary machine motor according to the real-time operating conditions of the electric auxiliary machine, and coordinates the power output matching between the new energy power supply system and the compressed air energy storage system.

[0009] A further improvement of this invention is that the function of coordinating the power output matching between the new energy power supply system and the compressed air energy storage system is achieved through the following method: When the power generation of new energy meets or exceeds the load demand of electric auxiliary equipment, the new energy power supply system directly supplies power to the electric auxiliary equipment and prioritizes the use of excess power to charge the compressed air energy storage system. When renewable energy generation is insufficient, the compressed air energy storage system is controlled to release electrical energy in a timely manner to make up for the power required by the electric auxiliary machine. When the combined power supply from new energy sources and energy storage is still insufficient to fully meet the load of electric auxiliary equipment, the thermal power unit provides backup power through the plant power system or the power grid to ensure the continuous and stable operation of the electric auxiliary equipment.

[0010] Secondly, the present invention provides a method for improving the energy efficiency of a multi-auxiliary power supply system in a thermal power plant based on the synergistic drive of new energy sources and compressed air energy storage, comprising the following steps: The central control system predicts the power generation of photovoltaic and wind power in different time periods based on meteorological data, and determines the load demand of electric auxiliary equipment in conjunction with the operation plan of thermal power units. When solar / wind power output is sufficient during the day, reduce the energy supply of thermal power units to electric auxiliary equipment; When the power generation of new energy exceeds the real-time load demand of electric auxiliary equipment, the compressed air energy storage system is controlled to enter charging mode, and the energy storage status is recorded at the same time. At night or during periods when renewable energy output is insufficient, the compressed air energy storage system is controlled to enter discharge mode, releasing the stored compressed air to drive the expansion generator to generate electricity, providing the electric auxiliary machine with the power required for operation.

[0011] A further improvement of this invention is that, when reducing the power supply of the thermal power unit to the electric auxiliary equipment, the new energy power supply system is controlled to prioritize the output of power to drive the normal operation of the feedwater pump, coal mill, induced draft fan, and desulfurization slurry pump.

[0012] A further improvement of the present invention is that when the compressed air energy storage system is put into charging mode, the electric compressor is started to convert excess electrical energy into compressed air and store it in the air storage device.

[0013] A further improvement of this invention is that the central control system monitors changes in grid frequency and electric auxiliary machine power demand in real time, and dynamically adjusts the output of the new energy power supply system and the charging and discharging power of the compressed air energy storage system to maintain a balance between the power supply of the electric auxiliary machine and the output of renewable energy.

[0014] A further improvement of the present invention is that when the grid frequency is detected to be higher than a preset threshold, the central control system increases the load on the electric auxiliary machine side or increases the charging power of the compressed air energy storage system to absorb the excess power of the grid. When the grid frequency is detected to be lower than the preset threshold, the central control system reduces the power drawn by the electric auxiliary machine from the grid and promptly starts the compressed air energy storage system to discharge, thereby reducing the power output burden on the grid while providing the electric auxiliary machine with the required power.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The new energy power generation unit of this invention directly provides power to the electric auxiliary machine, supplemented by a compressed air energy storage device as a buffer. This device can absorb excess energy when there is a surplus of new energy and provide compensating power when there is a shortage, avoiding excessive dependence of the electric auxiliary machine on the main unit's steam extraction and grid power supply. The central control system has developed a comprehensive control strategy for this coordinated energy supply structure, including functional modules such as new energy output prediction, real-time grid frequency detection, and dynamic matching control of the electric auxiliary machine load. The central control system can predict the power generation capacity of new energy sources such as photovoltaics and wind power, as well as the load demand of the electric auxiliary machine, monitor the grid frequency to determine the system's frequency regulation requirements, and integrate this information to optimize the charging and discharging process of the new energy power generation and compressed air energy storage system under different operating conditions, ensuring that the electric auxiliary machine always receives stable and efficient power support. Attached Figure Description

[0016] Figure 1 This is a system diagram of the present invention; Among them, 1. New energy power supply system; 2. Compressed air energy storage system; 3. Electric auxiliary machine; 4. Central control system; 5. Wind power generation device; 6. Photovoltaic power generation device; 7. Electric compressor; 8. Gas storage device; 9. Expansion power generation device; 10. Water pump; 11. Coal mill; 12. Exhaust fan; 13. Desulfurization slurry pump. Detailed Implementation

[0017] To further understand the content of this invention, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0018] See Figure 1 A multi-auxiliary power supply system for thermal power plants based on the synergistic drive of new energy and compressed air energy storage includes a new energy power supply system 1, a compressed air energy storage system 2, several electric auxiliary machines 3, and a central control system 4. The new energy power supply system 1 is used to provide power to the electric auxiliary equipment of the thermal power plant and send the excess energy into the compressed air energy storage system 2 to store energy; The compressed air energy storage system 2 is used to store excess energy and release it to power the electric auxiliary machine when energy is insufficient; The electric auxiliary machine obtains the required electrical energy by being driven by an electric motor and connected to the electric auxiliary machine power supply bus. The central control system 4 is used to monitor the power generation of new energy sources, the energy storage status and the load demand of electric auxiliary machine 3, and coordinate the charging and discharging of new energy power supply system 1 and compressed air energy storage system 2 according to grid frequency signals and power prediction information. During the day, it prioritizes the use of photovoltaic / wind power to drive electric auxiliary machine 3 and charge compressed air energy storage system 2. At night or when the output of new energy sources is insufficient, it releases compressed air to expand and generate electricity to power electric auxiliary machine 3.

[0019] An energy efficiency improvement method for multi-auxiliary power supply systems in thermal power plants based on the synergistic drive of new energy sources and compressed air energy storage includes the following steps: Step 1: The central control system 4 predicts the power generation of photovoltaic and wind power in various future periods based on meteorological data, and determines the load demand of electric auxiliary machine 3 in conjunction with the thermal power unit operation plan.

[0020] Step 2: When the photovoltaic / wind power output is sufficient during the day, control the new energy power supply system 1 to prioritize the output of power to drive the electric auxiliary machines such as feedwater pump 10, coal mill 11, induced draft fan 12, and desulfurization slurry pump 13 to operate normally, and minimize the power supply of the thermal power unit's conventional power generation to the electric auxiliary machines 3.

[0021] Step 3: When the power generation of new energy exceeds the real-time load demand of electric auxiliary machine 3, control the compressed air energy storage system 2 to enter the charging mode, start the electric compressor 7 to convert the excess electrical energy into compressed air and store it in the air storage device 8, and record the energy storage status at the same time.

[0022] Step four: At night or during periods when the output of new energy sources is insufficient, control the compressed air energy storage system 2 to enter the discharge mode, release the stored compressed air to drive the expansion generator 9 to generate electricity, provide the electric auxiliary machine 3 with the power required for operation, and make up for the lack of new energy power at this time.

[0023] Step 5: The central control system 4 monitors the changes in grid frequency and power demand of electric auxiliary machine 3 in real time, and dynamically adjusts the output of new energy power supply system 1 and the charging and discharging power of compressed air energy storage system 2 to keep the power supply of electric auxiliary machine 3 and the output of renewable energy in balance. When the grid frequency deviates from the standard, it absorbs or releases energy by increasing or decreasing the power of energy storage system to ensure that electric auxiliary machine obtains a stable power supply while assisting the grid to operate stably.

[0024] Example 1: The central control system 4 includes a power prediction module, a frequency detection module, and a load matching control module. The power prediction module is used to predict the power output of the photovoltaic power generation device 6 and the wind power generation device 5 based on meteorological and historical data, and to estimate the load demand of each electric auxiliary machine 3. The frequency detection module is used to monitor the grid frequency deviation in real time and obtain the operating condition information of the thermal power unit. The load matching control module optimizes the power allocation strategy between the new energy power supply system 1 and the compressed air energy storage system 2 according to the prediction and detection results, formulates the power supply plan of the electric auxiliary machine 3 in advance, and adjusts the power output allocation of the new energy and the charging and discharging power of the energy storage in real time when the actual output of the new energy does not match the prediction or when the grid frequency is detected to be abnormal, so as to achieve a dynamic balance between the load of the electric auxiliary machine 3 and the available power supply, ensure the stable and reliable power output during the power supply process of the electric auxiliary machine 3, thereby making full use of the new energy power and avoiding the electric auxiliary machine from affecting the operation of the unit due to unstable power supply.

[0025] Example 2: The compressed air energy storage system 2 includes an electric compressor 7, an air storage device 8, and an expansion power generation device 9. The electric compressor 7 is connected to the power supply bus of the electric auxiliary machine 3 and is controlled by the central control system 4. When there is excess power from renewable energy generation, it starts to compress air into the air storage tank or underground cavity for storage. At the same time, the heat energy generated during the compression process is recovered and stored through the heat storage device. Under the control of the central control system 4, the compressed air energy storage system 2 releases the stored high-pressure air for expansion power generation during peak electricity consumption or when renewable energy output decreases. The heat energy provided by the heat storage device is used to reheat the expanded air to improve power generation efficiency. Its output power is connected to the power supply bus of the electric auxiliary machine to power the electric auxiliary machine 3. In this way, the system can efficiently store and release surplus renewable energy during the day and utilize it at night, improve energy utilization and smooth the supply and demand difference between renewable energy and the load of the electric auxiliary machine 3.

[0026] Example 3: Multiple electric auxiliary machines 3 are connected to a unified electric auxiliary machine power supply bus via frequency converters. This electric auxiliary machine power supply bus is simultaneously connected to the output terminal of the new energy power supply system 1 and the power generation output terminal of the compressed air energy storage system 2. The central control system 4 adjusts the speed and power of each electric auxiliary machine 3 motor according to the real-time operating conditions of the electric auxiliary machines 3, and coordinates the power output matching between the new energy power supply system 1 and the compressed air energy storage system 2: when the new energy power generation meets or exceeds the load demand of the electric auxiliary machines 3, the new energy power supply system directly supplies power to the electric auxiliary machines 3 and prioritizes the use of excess power for charging the compressed air energy storage system 2; when the new energy power generation is insufficient, the compressed air energy storage system 2 is controlled to release electrical energy in a timely manner to supplement the power required by the electric auxiliary machines 3; when the combined power supply of new energy and energy storage still cannot fully meet the load of the electric auxiliary machines 3, the thermal power unit provides backup power through the plant power system or the power grid to ensure the continuous and stable operation of the electric auxiliary machines 3. The above power supply allocation strategy ensures that the utilization of new energy is maximized during the energy consumption process of the electric auxiliary machines 3, reduces fossil energy consumption, and achieves continuous, reliable, and efficient power supply for the electric auxiliary machines.

[0027] Example 4: See Figure 1 On the load side, this system includes multiple auxiliary mechanical devices required for the operation of thermal power units. Typical electric auxiliary equipment includes: boiler feedwater pump 10, fuel mill 11, induced draft fan 12, and desulfurization slurry pump 13, etc. Traditionally, these electric auxiliary machines 3 are driven by steam extracted from the turbine or powered by the grid. In this invention, they are all driven by electric motors and connected to a unified electric auxiliary power supply bus, thus enabling operation using new energy sources and energy storage power. Specifically, the feedwater pump motor drives the boiler feedwater pump 10 to pressurize and deliver condensate to the boiler; the fuel mill motor drives the fuel mill 11 to grind coal into pulverized coal; the induced draft fan motor drives the induced draft fan 12 to draw flue gas from the boiler combustion process and discharge it through the dust removal and desulfurization device to the chimney; the desulfurization slurry circulation pump motor drives the desulfurization slurry pump 13 to circulate limestone absorbent slurry to the flue gas desulfurization tower to remove sulfur dioxide from the flue gas. These electric auxiliary machines are indispensable for the safe and stable operation of thermal power units, and their total energy consumption accounts for a certain proportion of the unit's power generation (typically about 5% to 8%). By using electric motors for drive and co-supplying energy from new energy sources, the energy utilization efficiency and control flexibility of these electric auxiliary machines are greatly improved. In addition, each electric auxiliary machine motor is preferably equipped with a variable frequency speed control device to adjust the speed and power according to real-time operating conditions. This not only further reduces the power consumption of the electric auxiliary machines but also provides the central control system 4 with a means to regulate the load of the electric auxiliary machines 3.

[0028] The central control system 4 is the core of this invention, used to coordinate and optimize the power supply to the electric auxiliary machine 3 by the new energy power supply system 1 and the compressed air energy storage system 2. The central control system 4 can be implemented using a computer monitoring system or an energy management system, and includes three main functional modules: prediction, monitoring, and control. (1) New energy power prediction module: Based on meteorological data and historical output, predict the power of wind power generation and photovoltaic power generation in different future periods, and predict the load demand of each electric auxiliary machine 3 in combination with the thermal power unit operation plan; (2) Power grid frequency monitoring module: Real-time acquisition of changes in power grid frequency and thermal power unit output power. When the system frequency is abnormal (such as higher or lower than the standard value), it is identified as a state of power surplus or shortage in the power grid. (3) Load matching control module: Based on the predicted output of new energy and the load of electric auxiliary machine 3, as well as the monitored grid frequency deviation, dynamically adjust the charging and discharging of new energy power supply system 1, compressed air energy storage system 2 and the working status of electric auxiliary machine motor to achieve optimized distribution among multiple energy flows.

[0029] Under the coordination of the central control system 4, the system of this invention follows the following priority control principles: Prioritizing the use of the new energy power supply system 1 to meet the real-time power demand of the electric auxiliary machine; when the new energy generation exceeds the needs of the electric auxiliary machine 3, controlling the electric compressor 7 to absorb excess energy for storage; when the new energy is insufficient to meet the load of the electric auxiliary machine 3, immediately starting the compressed air energy storage system 2 to discharge and supplement power; in special circumstances where the new energy and energy storage still cannot fully cover the load of the electric auxiliary machine 3, then the thermal power unit supplies power through the plant power system or the power grid as backup support. Through the above strategies, the electric auxiliary machine 3 obtains a continuous and stable power supply, and maximizes the use of new energy to reduce fossil fuel consumption. Based on the coordinated control of the central control system 4, the system of this invention can achieve optimized allocation and conversion of energy supply for the electric auxiliary machine 3 during different operating periods.

[0030] During the daytime, when there is sufficient sunlight, high photovoltaic output, and some wind power output, the central control system will directly supply most of the electricity provided by the photovoltaic power generation unit 6 and the wind power generation unit 5 to the electric auxiliary machines. The remaining surplus electricity will drive the electric compressor 7 to charge the gas storage device for energy storage. At this time, the thermal power unit can appropriately reduce its output to save fuel consumption, because the load of the electric auxiliary machine 3 is mainly borne by new energy sources. At night, when there is no photovoltaic output and the wind power output may decrease or fluctuate, the central control system 4 will then instruct the compressed air energy storage system 2 to enter the discharge mode: the high-pressure air in the gas storage device 8 is released and drives the expansion generator 9 to generate electricity, which is then sent to the electric auxiliary machine bus to supply the electric auxiliary machines 3, thereby compensating for the lack of new energy sources.

[0031] If the wind power output is high at night and exceeds the load demand of the electric auxiliary unit 3, the system can also continue to compress and store energy at night using surplus wind power to ensure energy supply for subsequent periods. Through this daytime charging and nighttime discharging and on-demand switching operation mode, the energy consumption of the electric auxiliary unit can smoothly track the fluctuations in renewable energy output. This not only ensures that the normal operation of the electric auxiliary unit 3 of the thermal power plant is not affected by the intermittency of renewable energy, but also achieves peak shaving and valley filling—absorbing surplus renewable energy during off-peak periods and releasing stored energy during peak periods to reduce the power supply burden on the main system.

[0032] The implementation of this invention effectively improves the operational economy and flexibility of thermal power units. Since the key electric auxiliary machine 3 is powered by new energy sources and energy storage, the turbine does not need to extract steam for the electric auxiliary machine 3, optimizing the main unit's thermal cycle and improving the unit's power generation efficiency. Simultaneously, the enhanced independence of the electric auxiliary machine 3's power supply enables the thermal power unit to operate stably over a wider load range: during deep peak shaving, even if the boiler load drops to the minimum technical output level, the basic power required by the electric auxiliary machine 3 can still be provided by new energy sources and energy storage, thus preventing the unit from being forced to shut down due to insufficient load on the electric auxiliary machine 3. Furthermore, when grid frequency fluctuates, the central control system 4 can participate in frequency regulation by adjusting the power consumption of the electric auxiliary machine 3 and the charging and discharging power of the energy storage system. For example, when the frequency is too high, the load on the electric compressor 7 can be increased or the power consumption of the electric auxiliary machine can be increased; when the frequency is too low, the electric auxiliary machine's power draw from the grid can be reduced and compensated in a timely manner by the compressed air energy storage system 2, providing a certain degree of stability support to the grid. In summary, the method of using new energy sources and compressed air energy storage to synergistically drive the electric auxiliary machine 3 for power supply can maximize the utilization rate of clean energy, reduce coal consumption and pollution emissions, and has significant technical and economic benefits while ensuring the safe production of thermal power plants.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A multi-auxiliary power supply system for thermal power plants based on the synergistic drive of new energy sources and compressed air energy storage, characterized in that, It includes a new energy power supply system (1), a compressed air energy storage system (2), several electric auxiliary machines (3) and a central control system (4). The new energy power supply system (1) is used to provide power to the electric auxiliary machines of thermal power plants and send the excess energy into the compressed air energy storage system (2) to store energy; The compressed air energy storage system (2) is used to store excess energy and release energy to power electric auxiliary machines when energy is insufficient; The electric auxiliary machine obtains the required electrical energy by being driven by an electric motor and connected to the electric auxiliary machine power supply bus. The central control system (4) is used to monitor the power generation of new energy, the energy storage status and the load demand of electric auxiliary machine (3), and coordinate the charging and discharging of new energy power supply system (1) and compressed air energy storage system (2) according to grid frequency signal and power prediction information. During the day, photovoltaic / wind power is used to drive electric auxiliary machine (3) and charge compressed air energy storage system (2). At night or when the output of new energy is insufficient, compressed air is released to expand and generate electricity to power electric auxiliary machine (3).

2. The multi-auxiliary power supply system for thermal power plants based on the synergistic drive of new energy and compressed air energy storage as described in claim 1, characterized in that, The central control system (4) includes: The power prediction module is used to predict the power output of the photovoltaic power generation device (6) and the wind power generation device (5) based on meteorological and historical data and to estimate the load demand of each electric auxiliary machine (3). The frequency detection module is used to monitor the grid frequency deviation in real time and obtain the operating status information of thermal power units; The load matching control module is used to optimize the power distribution strategy between the new energy power supply system (1) and the compressed air energy storage system (2) based on the prediction and detection results, formulate the power supply plan of the electric auxiliary machine (3) in advance, and adjust the power distribution of the new energy and the charging and discharging power of the energy storage in real time when the actual output of the new energy does not match the prediction or when the grid frequency is detected to be abnormal.

3. The multi-auxiliary power supply system for thermal power plants based on the synergistic drive of new energy and compressed air energy storage as described in claim 1, characterized in that, The compressed air energy storage system (2) includes an electric compressor (7), an air storage device (8), and an expansion power generation device (9). The electric compressor (7) is connected to the power supply bus of the electric auxiliary machine (3) and controlled by the central control system (4). When the power generation of new energy is excessive, it starts to compress air into the storage tank or underground cavity for storage. At the same time, it recovers and stores the heat energy generated during the compression process through the heat storage device. The compressed air energy storage system (2) releases the stored high-pressure air for expansion and power generation during peak electricity demand or when the output of new energy sources decreases, under the control of the central control system (4). It also uses the heat energy provided by the heat storage device to reheat the expanded air to improve the power generation efficiency. Its output power is connected to the power supply bus of the electric auxiliary machine to power the electric auxiliary machine (3) equipment.

4. The multi-auxiliary power supply system for thermal power plants based on the synergistic drive of new energy and compressed air energy storage as described in claim 1, characterized in that, The electric auxiliary machine (3) is connected to the unified electric auxiliary machine power supply bus through the frequency conversion drive device. The electric auxiliary machine power supply bus is simultaneously connected to the output end of the new energy power supply system (1) and the power generation output end of the compressed air energy storage system (2). The central control system (4) adjusts the speed and power of the motors of each electric auxiliary machine (3) according to the real-time operating conditions of the electric auxiliary machine (3), and coordinates the power output matching between the new energy power supply system (1) and the compressed air energy storage system (2).

5. The multi-auxiliary power supply system for thermal power plants based on the synergistic drive of new energy and compressed air energy storage as described in claim 4, characterized in that, The function of coordinating the power output matching between the new energy power supply system (1) and the compressed air energy storage system (2) is achieved through the following method: When the new energy power generation meets or exceeds the load demand of the electric auxiliary machine (3), the new energy power supply system directly supplies power to the electric auxiliary machine (3) and prioritizes the use of excess power to charge the compressed air energy storage system (2); When the power generation of new energy sources is insufficient, the compressed air energy storage system (2) is controlled to release electrical energy in a timely manner to make up for the power required by the electric auxiliary machine (3); When the combined power supply of new energy and energy storage is still insufficient to fully meet the load of electric auxiliary machine (3), the thermal power unit provides backup power through the plant power system or the power grid to ensure the continuous and stable operation of electric auxiliary machine (3).

6. A method for improving the energy efficiency of a multi-auxiliary power plant energy supply system based on the synergistic drive of new energy sources and compressed air energy storage as described in claim 1, characterized in that, Includes the following steps: The central control system (4) predicts the power generation of photovoltaic and wind power in each future period based on meteorological data, and determines the load demand of electric auxiliary equipment (3) in conjunction with the thermal power unit operation plan; When the photovoltaic / wind power output is sufficient during the day, reduce the power supply of the thermal power unit to the electric auxiliary machine (3); When the power generation of new energy exceeds the real-time load demand of electric auxiliary machine (3), the compressed air energy storage system (2) is controlled to enter the charging mode, and the energy storage status is recorded at the same time. At night or during periods when new energy output is insufficient, the compressed air energy storage system (2) is controlled to enter the discharge mode, releasing the stored compressed air to drive the expansion generator (9) to generate electricity, providing the electric auxiliary machine (3) with the power required for operation.

7. The energy efficiency improvement method for a multi-auxiliary power plant energy supply system based on the synergistic drive of new energy and compressed air energy storage as described in claim 6, characterized in that, When reducing the power supply of the thermal power unit to the electric auxiliary machine (3), the new energy power supply system (1) is controlled to give priority to outputting power to drive the normal operation of the feed water pump (10), coal mill (11), induced draft fan (12), and desulfurization slurry pump (13).

8. The energy efficiency improvement method for a multi-auxiliary power plant energy supply system based on the synergistic drive of new energy and compressed air energy storage as described in claim 6, characterized in that, When the compressed air energy storage system (2) is put into charging mode, the electric compressor (7) is started to convert excess electrical energy into compressed air and store it in the air storage device (8).

9. The energy efficiency improvement method for a multi-auxiliary power plant energy supply system based on the synergistic drive of new energy and compressed air energy storage as described in claim 6, characterized in that, The central control system (4) monitors the changes in grid frequency and power demand of electric auxiliary machine (3) in real time, and dynamically adjusts the output of new energy power supply system (1) and the charging and discharging power of compressed air energy storage system (2) to keep the power supply of electric auxiliary machine (3) and the output of renewable energy in balance.

10. The energy efficiency improvement method for a multi-auxiliary power plant energy supply system based on the synergistic drive of new energy and compressed air energy storage as described in claim 6, characterized in that, When the grid frequency is detected to be higher than the preset threshold, the central control system (4) increases the load on the electric auxiliary machine (3) side or increases the charging power of the compressed air energy storage system (2) to absorb the surplus power of the grid. When the power grid frequency is detected to be lower than the preset threshold, the central control system (4) reduces the power drawn from the power grid by the electric auxiliary machine (3) and starts the compressed air energy storage system (2) to discharge in a timely manner, thereby reducing the power grid output burden while providing the electric auxiliary machine (3) with the required power.

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