Water-gas coupling compressed air energy storage system and grid-connected control method thereof

Abstract

The invention discloses a water-gas coupling compressed air energy storage system and a grid-connected control method thereof, a gas storage system comprises a constant-pressure gas storage, an upper reservoir and a gas processing subsystem, and the constant-pressure gas storage stores at least one of stored water and gas; the gas treatment subsystem is specifically used for conveying compressed air to the constant-pressure gas storage through a gas circulation pipeline in an energy storage stage, so that part or all of water in the constant-pressure gas storage is conveyed to the upper reservoir through a water diversion pipeline; in the energy release stage, compressed air released by the constant-pressure gas storage is adopted to do work so as to generate electric energy; and the electric energy generated by the gas treatment subsystem is merged into a power grid through a grid-connected inverter regulated and controlled by the virtual synchronous machine. Compressed gas is stored by using the water-gas coupled constant-pressure gas storage, and the pressure intensity of the constant-pressure gas storage is adjusted through the upper reservoir, so that the pressure intensity in the constant-pressure gas storage is kept constant in the energy storage and release process, and the problem of unstable system operation caused by a constant-volume gas storage is solved.

Description

Technical Field

[0001] This invention relates to the field of energy storage systems and grid connection control technology, specifically to a water-air coupled compressed air energy storage system and its grid connection control method. Background Technology

[0002] As a core sector of carbon emissions, the power industry benefits from building a new power system based on renewable energy sources, which will accelerate the decarbonization process. Utilizing the flexible charging and discharging characteristics of energy storage can effectively mitigate fluctuations in renewable energy levels, promote renewable energy consumption, and assist in grid peak shaving. Therefore, energy storage systems are widely used in current power systems.

[0003] Compressed air energy storage (CAES) utilizes the compression and release of air to store and release energy, offering advantages such as large capacity, flexible deployment, and short construction periods, attracting significant attention from industry and academia. However, most currently operational and under-construction CAES systems utilize constant-volume gas storage facilities such as salt caverns and artificial chambers. This leads to substantial pressure fluctuations in the storage facility during the energy storage and release cycle. These pressure fluctuations cause the CAES to deviate from its rated operating point, resulting in system instability. Summary of the Invention

[0004] The purpose of this invention is to provide a water-gas coupled compressed air energy storage system and its grid-connected control method. By using a water-gas coupled constant-pressure gas storage tank to store compressed gas, and by adjusting the pressure of the constant-pressure gas storage tank through an upper water tank, the pressure inside the constant-pressure gas storage tank is kept constant during the energy storage and release process, thus solving the problem of system instability caused by constant-capacity gas storage tanks.

[0005] This invention is achieved through the following technical solution:

[0006] The first aspect of this application provides a water-gas coupled compressed air energy storage system, the energy storage system including a constant pressure gas storage tank, an upper water tank and a gas processing subsystem, wherein the constant pressure gas storage tank stores at least one of water and gas;

[0007] The gas processing subsystem is specifically used for: in the energy storage stage, delivering compressed air to the constant pressure gas storage tank through a gas flow pipeline, so that some or all of the water in the constant pressure gas storage tank is delivered to the upper reservoir through a water intake pipeline to maintain a constant pressure in the gas storage tank; in the energy release stage, water from the upper reservoir is delivered to the constant pressure gas storage tank through a water intake pipeline to maintain a stable pressure in the gas storage tank, and generating electrical energy by using the compressed air released from the constant pressure gas storage tank to do work.

[0008] The electrical energy generated by the gas processing subsystem is fed into the power grid via a virtual synchronous machine that controls the grid-connected inverter.

[0009] In one feasible implementation, the gas handling subsystem includes a compressor, a first heat exchanger, and a first heat storage tank;

[0010] The first heat exchanger is used to transfer the heat generated by the compressor compressing gas to the first heat storage tank, and to transport the compressed gas to the constant pressure gas storage tank through the gas flow pipeline.

[0011] In one feasible implementation, the gas handling subsystem further includes: a second heat exchanger, an expander, and a generator;

[0012] The second heat exchanger is used to heat the gas released from the constant pressure gas storage tank with the heat obtained from the first heat storage tank, and to transport the heated gas to the expander to drive the expander to do work and drive the generator to generate electricity.

[0013] In one feasible implementation, the gas handling subsystem further includes a second heat storage tank for collecting heat from a second heat exchanger and transferring the collected heat to a first heat exchanger.

[0014] A second aspect of this application provides a grid-connected control method for a water-air coupled compressed air energy storage system, the method comprising:

[0015] By simulating the rotor motion characteristics of a synchronous generator, the angular velocity and active power are controlled to output the controlled angular frequency and phase.

[0016] By simulating the excitation voltage regulation characteristics of a synchronous generator, the voltage value and reactive power are regulated to output a regulated voltage.

[0017] Based on the controlled angular frequency, phase, and controlled voltage, an output voltage reference signal for the grid-connected inverter is generated.

[0018] The output voltage reference signal is used for: the grid-connected inverter to convert the DC voltage generated by the water-air coupled compressed air energy storage system into AC voltage.

[0019] In one feasible implementation, the rotor motion characteristics of the synchronous generator are specifically as follows:

[0020]

[0021] In the formula, P e P represents the grid-connected active power. ref M represents the active reference power, M=Jω0 represents the equivalent virtual inertia, J represents the virtual inertia, ω0 represents the rated angular frequency, ω represents the adjustable angular frequency, and D represents the active reference power. i (i=1,2) represents the virtual damping, also known as the primary frequency modulation parameter, and λ is... This represents the coefficient of a fractional integral.

[0022] In one feasible implementation, the excitation voltage regulation characteristics of the synchronous generator are specifically as follows:

[0023]

[0024] In the formula, E represents the regulating voltage, E0 represents the rated voltage, and k q This represents the primary voltage regulation parameter, Qe represents the grid-connected reactive power, and Q... ref This indicates the reactive power reference power.

[0025] In one feasible implementation, the step of regulating angular velocity and active power by simulating the rotor motion characteristics of a synchronous generator to output a regulated angular frequency and phase includes:

[0026] The angular frequency deviation between the rated angular frequency and the actual angular frequency is proportionally amplified to generate a frequency deviation control quantity;

[0027] The power deviation between the active reference power and the actual active power is superimposed with the frequency deviation control amount to generate a first superimposed signal;

[0028] The first superimposed signal is adjusted by virtual damping and virtual inertia to output the controlled angular frequency and phase.

[0029] In one feasible implementation, the step of regulating the voltage value and reactive power by simulating the excitation voltage regulation characteristics of a synchronous generator to output a regulated voltage includes:

[0030] The voltage deviation is determined based on the voltage reference value and the effective voltage value.

[0031] Based on the reactive power reference power and the actual reactive power, determine the reactive power deviation;

[0032] The voltage deviation and the reactive power deviation are superimposed to generate a second superimposed signal;

[0033] The second superimposed signal is integrated and adjusted to output a control voltage.

[0034] A third aspect of this application provides a grid-connected control device for a water-air coupled compressed air energy storage system, the device comprising:

[0035] The first control unit is used to control the angular velocity and active power by simulating the rotor motion characteristics of a synchronous generator, so as to output the control angular frequency and phase.

[0036] The second control unit is used to regulate the voltage value and reactive power by simulating the excitation voltage regulation characteristics of a synchronous generator, so as to output the regulated voltage.

[0037] The signal generation unit generates an output voltage reference signal for the grid-connected inverter based on the controlled angular frequency, phase, and controlled voltage.

[0038] The output voltage reference signal is used for: the grid-connected inverter to convert the DC voltage generated by the water-air coupled compressed air energy storage system into AC voltage.

[0039] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0040] In the energy storage system of this embodiment, a gas processing subsystem is connected to a constant-pressure gas storage tank. During the energy storage phase, compressed gas from the gas processing subsystem is stored in the constant-pressure gas storage tank. Since the constant-pressure gas storage tank is connected to an upper reservoir, the compressed gas forces water from the constant-pressure gas storage tank into the upper reservoir, thus maintaining a constant gas pressure within the constant-pressure gas storage tank. During the energy release phase, water is injected into the constant-pressure gas storage tank from the upper reservoir, forcing the compressed gas into the gas processing subsystem. The gas processing subsystem then generates electricity for grid connection. Furthermore, during the energy release process, water is injected from the upper reservoir as the compressed gas flows out of the constant-pressure gas storage tank, maintaining a constant gas pressure within the tank. Therefore, the energy storage system of this embodiment can consistently output compressed gas, thereby generating electricity relatively stably, ensuring the stable operation of the energy storage system. Attached Figure Description

[0041] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0042] Figure 1 A schematic diagram of a water-air coupled compressed air energy storage system provided in this application embodiment;

[0043] Figure 2 A schematic flowchart illustrating a grid-connected control method for a water-air coupled compressed air energy storage system provided in this application embodiment;

[0044] Figure 3 This is a schematic diagram illustrating the control principle of the virtual synchronous machine in the grid-connected control method provided in the embodiments of this application;

[0045] Figure 4 A schematic diagram of the grid-connected control device for a water-air coupled compressed air energy storage system provided in this application embodiment;

[0046] Figure 5This application provides a schematic diagram of the structure of a computing device according to an embodiment of the present application;

[0047] In the diagram, 101 is the upper reservoir, 102 is the water diversion pipeline, 103 is the constant pressure gas storage tank, 104 is the electric motor, 105 is the compressor, 106 is the first heat exchanger, 107 is the first heat storage tank, 108 is the second heat storage tank, 109 is the expander, 110 is the generator, 111 is the gas flow pipeline, 112 is the valve, and 113 is the second heat exchanger. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The illustrative embodiments and descriptions of this invention are for explanation only and are not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this application.

[0049] As will be known to those skilled in the art, with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0050] The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, product, or apparatus.

[0051] Example 1

[0052] Embodiment 1 of this application provides a water-gas coupled compressed air energy storage system to solve the problem of system instability caused by existing constant-capacity gas storage facilities.

[0053] The water-gas coupled compressed air energy storage system in this embodiment includes a constant pressure gas storage tank, an upper water tank, and a gas processing subsystem.

[0054] A constant-pressure gas storage facility stores at least one of water and gas. Typically, it stores a mixture of water and gas, with the upper part containing gas and the lower part containing water. In extreme cases, if a large amount of compressed gas is stored in the constant-pressure gas storage facility, all the water will be forced out to maintain a constant pressure, flowing through pipes into an upper water reservoir. However, normally, valves on the gas flow pipelines are controlled as needed to prevent such extreme situations.

[0055] The gas processing subsystem is specifically used for: in the energy storage stage, delivering compressed air to the constant pressure gas storage tank through gas circulation pipelines, so that some or all of the water in the constant pressure gas storage tank is delivered to the upper reservoir through water intake pipelines; in the energy release stage, using the compressed air released from the constant pressure gas storage tank to do work to generate electricity; the electricity generated by the gas processing subsystem is connected to the grid by controlling the grid-connected inverter through a virtual synchronous machine.

[0056] like Figure 1 The diagram shows a schematic of the specific structure of a water-air coupled compressed air energy storage system. The energy storage system specifically includes an upper water reservoir 101, a water intake pipeline 102, a constant pressure air storage tank 103, an electric motor 104, a compressor 105, a first heat exchanger 106, a first heat storage tank 107, a second heat storage tank 108, an expander 109, a generator 110, a gas flow pipeline 111, a valve 112, and a second heat exchanger 113.

[0057] In one feasible implementation, the gas handling subsystem includes an electric motor 104, a compressor 105, a first heat exchanger 106, and a first heat storage tank 107;

[0058] In this implementation, the electric motor 104 drives the compressor 104 to work, compressing the air (or gas) to high pressure. The first heat exchanger 106 recovers the heat of compression and stores it in the first heat storage tank 107, and delivers the compressed air at room temperature to the constant pressure gas storage tank 103 through the gas flow pipeline 111.

[0059] After compressed air enters the constant pressure air storage 103, the air pressure inside the constant pressure air storage 103 increases for a short time. This will push the water inside the constant pressure air storage 103 to be transported to the upper water reservoir 101 through the water inlet pipe 102. The upper water reservoir 101 then provides a basically constant water seal pressure to the compressed air in the constant pressure air storage 103 through the water inlet pipe 102.

[0060] In addition, the first heat storage tank 107 is used to store the thermal energy of compressed air to avoid energy waste, and the stored thermal energy can be utilized during the energy release phase.

[0061] This implementation method realizes the energy storage process of the energy storage system.

[0062] In another feasible implementation, the gas handling subsystem includes a second heat exchanger 113, an expander 109, and a generator 110.

[0063] In this implementation, the water in the upper reservoir 101 gradually returns to the constant pressure gas storage tank 103 via the water diversion pipe 102. The compressed air in the constant pressure gas storage tank 103 is continuously pushed out and enters the second heat exchanger 113 via the gas flow pipe 111. The second heat exchanger 113 obtains heat from the first heat storage tank 107 and uses the obtained heat to heat the air released from the constant pressure gas storage tank (or, reheat the compressed air). The heated compressed air is then transported to the expander 109 to drive the expander 109 to do work and drive the generator 110 to generate electricity.

[0064] This implementation method realizes the energy release process of the energy storage system. During this energy release process, the air pressure inside the constant-pressure gas storage tank remains essentially constant.

[0065] In both of the above feasible implementation methods, the gas processing subsystem can include a second heat storage tank 108. During the energy release phase, the second heat storage tank 108 obtains heat from the gas from the second heat exchanger 113 and sends it to the first heat exchanger 106. Both the second heat storage tank 108 and the first heat storage tank 107 are used to store heat, and under normal circumstances, the temperature of the first heat storage tank 107 is higher than the temperature of the second heat storage tank 108.

[0066] It should be noted that during the energy storage and release phases described above, valve 112 is in the open state to facilitate the smooth passage of air through gas circulation pipe 111.

[0067] In the energy storage system of this embodiment, a gas processing subsystem is connected to a constant-pressure gas storage tank. During the energy storage phase, compressed gas from the gas processing subsystem is stored in the constant-pressure gas storage tank. Since the constant-pressure gas storage tank is connected to an upper reservoir, the compressed gas forces water from the constant-pressure gas storage tank into the upper reservoir, thus maintaining a constant gas pressure within the constant-pressure gas storage tank. During the energy release phase, water is injected into the constant-pressure gas storage tank from the upper reservoir, forcing the compressed gas into the gas processing subsystem. The gas processing subsystem then generates electricity for grid connection. Furthermore, during the energy release process, water is injected from the upper reservoir as the compressed gas flows out of the constant-pressure gas storage tank, maintaining a constant gas pressure within the tank. Therefore, the energy storage system of this embodiment can consistently output compressed gas, thereby generating electricity relatively stably, ensuring the stable operation of the energy storage system.

[0068] Example 2

[0069] In order to stably integrate the electrical energy generated by the water-air coupled compressed air energy storage system of one embodiment into the power grid, this embodiment provides a grid connection control method for the water-air coupled compressed air energy storage system.

[0070] The subject executing this method can be any computing device capable of implementing the method, such as a server, mobile phone, personal computer, smart wearable device, smart robot, etc.

[0071] Furthermore, the embodiments of this application do not limit the execution order of different steps. When using the method provided in the embodiments of this application, the execution order of different steps can be adjusted according to actual needs.

[0072] To clearly explain this plan, the following points will be made first:

[0073] With the increasing integration of renewable energy into the power system in recent years, the demand for CAES (Compressed Air Storage System) based on constant-capacity gas storage is rising to meet the grid's growing flexibility requirements for energy storage while ensuring its own stable and efficient operation. In the water-gas coupled compressed air energy storage system of the above embodiment, the energy release stage connects the generated electricity to the grid via a grid-connected inverter. However, the grid-connected inverter suffers from weak instantaneous disturbance rejection and overload capacity, and prolonged active-frequency dynamic oscillations can easily trigger current surges. Therefore, this embodiment also aims to address the problems of dynamic oscillations and overshoot in the grid-connected power frequency.

[0074] For ease of description, the following uses a grid-connected control device for a water-air coupled compressed air energy storage system as the execution subject of this method to provide a detailed description of the method provided in this application embodiment.

[0075] It should be noted that the grid-connected control device in this embodiment can be abstracted as a virtual synchronous machine and integrated into the grid-connected inverter. It is used to regulate the output voltage of the grid-connected inverter to ensure stable grid connection. This enables the stationary grid-connected inverter to have the inertia and damping characteristics of a synchronous generator, thereby improving its ability to resist interference and fluctuations.

[0076] like Figure 2 The diagram shown is a flowchart illustrating the specific implementation of a grid-connected control method for a water-air coupled compressed air energy storage system according to an embodiment of this application, including the following steps 21 to 23:

[0077] Step 21: By simulating the rotor motion characteristics of a synchronous generator, the angular velocity and active power are controlled to output the controlled angular frequency and phase.

[0078] The rotor motion characteristics of a synchronous generator can be expressed as:

[0079]

[0080] In the formula, P e P represents the grid-connected active power. ref M represents the active reference power, M=Jω0 represents the equivalent virtual inertia, J represents the virtual inertia, ω0 represents the rated angular frequency, ω represents the adjustable angular frequency, and D represents the active reference power. i (i=1,2) represents the virtual damping, also known as the primary frequency modulation parameter, and λ is... This represents the coefficient of a fractional integral.

[0081] Based on the rotor motion characteristics of the synchronous generator, the angular velocity and active power are regulated to output the regulated angular frequency and phase, specifically including the following steps 2101 to 2103:

[0082] Step 2101: The angular frequency deviation between the rated angular frequency and the actual angular frequency is proportionally amplified to generate a frequency deviation control quantity.

[0083] Step 2102: The power deviation between the active reference power and the actual active power is superimposed with the frequency deviation control quantity to generate a first superimposed signal.

[0084] Step 2103: The first superimposed signal is adjusted by virtual damping and virtual inertia to output the controlled angular frequency and phase.

[0085] Step 22: By simulating the excitation voltage regulation characteristics of a synchronous generator, the voltage value and reactive power are regulated to output a regulated voltage.

[0086] The excitation voltage regulation characteristics of a synchronous generator can be expressed as:

[0087]

[0088] In the formula, E represents the regulating voltage, E0 represents the rated voltage, and k q This represents the primary voltage regulation parameter, Qe represents the grid-connected reactive power, and Q... ref This indicates the reactive power reference power.

[0089] By simulating the rotor motion characteristics of a synchronous generator, the angular velocity and active power are controlled to output the controlled angular frequency and phase, including steps 2201 to 2203:

[0090] Step 2201: The angular frequency deviation between the rated angular frequency and the actual angular frequency is proportionally amplified to generate a frequency deviation control quantity;

[0091] Step 2202: The power deviation between the active reference power and the actual active power is superimposed with the frequency deviation control amount to generate a first superimposed signal;

[0092] Step 2203: The first superimposed signal is adjusted by virtual damping and virtual inertia to output the controlled angular frequency and phase.

[0093] Step 23: Based on the controlled angular frequency, phase, and controlled voltage, generate the output voltage reference signal of the grid-connected inverter.

[0094] The output voltage reference signal is used for: the grid-connected inverter to convert the DC voltage generated by the water-air coupled compressed air energy storage system into AC voltage.

[0095] like Figure 3 The diagram shown is a schematic diagram of the working principle of the virtual synchronizing machine of the water-air coupled compressed air energy storage system provided in this embodiment, which includes a control circuit (within the dashed box) and a main circuit.

[0096] Based on the control principles of steps 21 and 22 above, the control circuit regulates the voltage input to the grid-connected inverter from the water-air coupled compressed air energy storage system, so that the grid-connected inverter has the inertia and damping characteristics of a synchronous generator, thereby improving its ability to resist interference and fluctuations.

[0097] The control circuit includes modeling the rotor motion characteristics based on a synchronous generator, regulating the angular velocity and active power, i.e., P-ω speed control, to output angular frequency and phase. The specific process includes:

[0098] Using the deviation between the rated angular velocity ω0 and the actual angular velocity ω as input, this deviation is proportionally adjusted via the frequency modulation parameter kp to form the frequency deviation control quantity; this frequency deviation control quantity is then combined with the active power reference P. ref The deviation from the actual active power P is superimposed to generate a first superimposed signal. This first superimposed signal, through virtual damping adjustment and virtual inertia adjustment, simulates the rotor motion characteristics of a synchronous generator, ultimately outputting the angular frequency ω and phase ωt of the voltage. The virtual inertia adjustment is achieved by calculating the equivalent virtual inertia of the first superimposed signal. Virtual damping adjustment is achieved by integrating the calculated results of the equivalent virtual inertia. The integral result is adjusted by virtual damping. , The signal is superimposed again with the first superimposed signal to achieve virtual inertia adjustment process, and the signal obtained by superposition again repeatedly performs the virtual inertia adjustment process until the deviation between the actual angular frequency and the actual active power and the corresponding reference value meets the predetermined condition, and the angular frequency ω and phase ωt of the output voltage are obtained.

[0099] The control circuit also includes modeling the excitation voltage regulation characteristics based on the synchronous generator to regulate the voltage value and reactive power, i.e., QE excitation regulation, to output a regulated voltage. The specific process includes:

[0100] With voltage reference value U ref With respect to the actual effective value of voltage U abc Determine the voltage deviation; proportionally adjust this deviation using the voltage regulation parameter kq to form the voltage deviation control quantity; reactive power reference power Q ref The reactive power deviation is determined by comparing it with the actual reactive power Q; the voltage deviation control quantity and the reactive power deviation are superimposed and processed through a proportional element. The excitation voltage regulation characteristics of a synchronous generator are simulated, and the final output voltage amplitude is E.

[0101] Subsequently, the amplitude E and phase ωt are combined to generate the induced electromotive forces Ea, Eb, and Ec of the virtual synchronous machine (expanded into three phases via dq-abc transformation), which serve as the output voltage reference (regulation voltage) for the grid-connected inverter. In the diagram, and This represents the voltage command signal in a rotating coordinate system. Additionally, RMS in the diagram is the signal effective value calculation module, with the three-phase output voltage U as its input. abc The output is the effective value of the three-phase signal.

[0102] Further explanation is needed regarding the following: Voltage regulation equation (simulated excitation voltage regulation): By using kq (primary voltage regulation parameter), fractional integral coefficients, etc., the output voltage amplitude E tracks the rated value E0, simulating the excitation regulation characteristics of a synchronous generator to maintain voltage stability. Rotor motion equation (simulated inertia and damping): Through virtual inertia J and virtual damping Di, the system possesses "inertial buffering" and "damping to suppress oscillations" capabilities similar to a synchronous generator when active power and frequency fluctuate, improving its disturbance rejection capability.

[0103] Main circuit section: The energy output by the water-air coupled compressed air energy storage system during the energy release stage is converted into DC voltage Vdc by the AC / DC conversion circuit and input to the grid-connected inverter; the grid-connected inverter receives the voltage reference signal (regulation voltage signal) from the control section, generates a drive signal through PWM modulation, and inverts the DC power into AC power.

[0104] The main circuit also includes filtering and grid connection stages: after being processed by a filter circuit composed of inductor Lf and capacitor Cf, it is connected to the power grid through a circuit breaker (control switch) on the grid-connected / off-grid side, and can also supply power to AC loads. In the figure, Ea, Eb, and Ec are the induced electromotive forces of the virtual synchronous machine, Ua, Ub, and Uc are the three-phase output voltages of the virtual synchronous machine, and Ia, Ib, and Ic are the three-phase grid-connected currents of the virtual synchronous machine.

[0105] The control method in this embodiment, through P-ω speed regulation control and QE excitation regulation, can cope with Pref step disturbance (power reference command mutation) and fg step disturbance (external power grid frequency picture), solve the dynamic oscillation problem of active power and frequency, and make the system adjustment more stable (small overshoot).

[0106] Example 2

[0107] To address the problems of dynamic oscillation and overshoot in the grid-connected power frequency in the prior art, and based on the same inventive concept as Embodiment 2, this application also provides a grid-connected control device for a water-air coupled compressed air energy storage system.

[0108] A schematic diagram of the specific structure of the device is shown below. Figure 4 As shown, it includes the following functional units 41-43:

[0109] The first control unit 41 is used to control the angular velocity and active power by simulating the rotor motion characteristics of a synchronous generator, so as to output the control angular frequency and phase.

[0110] The rotor motion characteristics of a synchronous generator are as follows:

[0111]

[0112] In the formula, P e P represents the grid-connected active power. ref M represents the active reference power, M=Jω0 represents the equivalent virtual inertia, J represents the virtual inertia, ω0 represents the rated angular frequency, ω represents the adjustable angular frequency, and D represents the active reference power. i (i=1,2) represents the virtual damping, also known as the primary frequency modulation parameter, and λ is... This represents the coefficient of a fractional integral.

[0113] The first control unit is specifically used to: proportionally amplify the angular frequency deviation between the rated angular frequency and the actual angular frequency to generate a frequency deviation control quantity; superimpose the power deviation between the active reference power and the actual active power with the frequency deviation control quantity to generate a first superimposed signal; and output the control angular frequency and phase by subjecting the first superimposed signal to virtual damping adjustment and virtual inertia adjustment.

[0114] The second control unit 42 is used to regulate the voltage value and reactive power by simulating the excitation voltage regulation characteristics of a synchronous generator, so as to output the regulated voltage.

[0115] The excitation voltage regulation characteristics of a synchronous generator are as follows:

[0116]

[0117] In the formula, E represents the regulating voltage, E0 represents the rated voltage, and k q This represents the primary voltage regulation parameter, Qe represents the grid-connected reactive power, and Q... ref This indicates the reactive power reference power.

[0118] The second control unit is specifically used for: determining the voltage deviation based on the voltage reference value and the effective voltage value; determining the reactive power deviation based on the reactive power reference power and the actual reactive power; superimposing the voltage deviation and the reactive power deviation to generate a second superimposed signal; and outputting the control voltage by integral adjustment of the second superimposed signal.

[0119] The signal generation unit 43 generates the output voltage reference signal of the grid-connected inverter based on the control angular frequency, phase and control voltage.

[0120] The output voltage reference signal is used for: the grid-connected inverter to convert the DC voltage generated by the water-air coupled compressed air energy storage system into AC voltage.

[0121] The embodiments of this application, through P-ω speed regulation control and QE excitation regulation, can cope with Pref step disturbance (power reference command mutation) and fg step disturbance (external power grid frequency picture), solve the dynamic oscillation problem of active power and frequency, and make the system adjustment more stable (small overshoot).

[0122] Based on the same inventive concept as the foregoing embodiments of this application, this application also provides a computing device.

[0123] like Figure 5 As shown, the computing device includes a memory 501 and a processor 502. The memory 501 can be configured to store various other data to support operation on the electronic device. Examples of this data include instructions for any application or method used to operate on the electronic device. The memory 501 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0124] The processor 502, coupled to the memory 501, is used to execute the computer program stored in the memory 501 for performing a method for aggregating feasible domains of a virtual power plant as described in the foregoing embodiments.

[0125] When the processor 502 executes the computer program to perform the grid-connected control method of the water-air coupled compressed air energy storage system, it can cope with Pref step disturbance (power reference command mutation) and fg step disturbance (external grid frequency picture) through P-ω speed regulation control and QE excitation regulation, solve the dynamic oscillation problem of active power and frequency, and make the system adjustment more stable (small overshoot).

[0126] When the processor 502 executes the computer program in the memory 501, in addition to the functions described above, it can also perform other functions, as detailed in the descriptions of the preceding embodiments.

[0127] Furthermore, such as Figure 5 As shown, the computing device also includes other components such as a display 504, a communication component 503, a power supply component 505, and an audio component 506. Figure 5 The diagram only shows some components and does not mean that the computing device includes only these components. Figure 5 The components shown.

[0128] Accordingly, embodiments of this application also provide a computer-readable storage medium storing a computer program, which, when executed by a computer, can implement the methods provided in the above embodiments.

[0129] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0130] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments.

[0131] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A water-air coupled compressed air energy storage system, characterized in that, The energy storage system includes a constant-pressure gas storage tank, an upper water tank, and a gas processing subsystem. The constant-pressure gas storage tank stores at least one of water and gas. The gas processing subsystem is specifically used for: in the energy storage stage, delivering compressed air to the constant pressure gas storage tank through a gas flow pipeline, so that some or all of the water in the constant pressure gas storage tank is delivered to the upper reservoir through a water intake pipeline to maintain a constant pressure in the gas storage tank; in the energy release stage, water from the upper reservoir is delivered to the constant pressure gas storage tank through a water intake pipeline to maintain a stable pressure in the gas storage tank, and generating electrical energy by using the compressed air released from the constant pressure gas storage tank to do work. The electrical energy generated by the gas processing subsystem is fed into the power grid via a virtual synchronous machine that controls the grid-connected inverter.

2. The system according to claim 1, characterized in that, The gas handling subsystem includes a compressor, a first heat exchanger, and a first heat storage tank; The first heat exchanger is used to transfer the heat generated by the compressor compressing gas to the first heat storage tank, and to transport the compressed gas to the constant pressure gas storage tank through the gas flow pipeline.

3. The system according to claim 2, characterized in that, The gas handling subsystem further includes: a second heat exchanger, an expander, and a generator; The second heat exchanger is used to heat the gas released from the constant pressure gas storage tank with the heat obtained from the first heat storage tank, and to transport the heated gas to the expander to drive the expander to do work and drive the generator to generate electricity.

4. The method according to claim 3, characterized in that, The gas handling subsystem also includes a second heat storage tank, which is used to collect heat from the second heat exchanger and transport the collected heat to the first heat exchanger.

5. A grid-connected control method for a water-air coupled compressed air energy storage system, characterized in that, The method includes: By simulating the rotor motion characteristics of a synchronous generator, the angular velocity and active power are controlled to output the controlled angular frequency and phase. By simulating the excitation voltage regulation characteristics of a synchronous generator, the voltage value and reactive power are regulated to output a regulated voltage. Based on the controlled angular frequency, phase, and controlled voltage, an output voltage reference signal for the grid-connected inverter is generated. The output voltage reference signal is used for: the grid-connected inverter to convert the DC voltage generated by the water-air coupled compressed air energy storage system into AC voltage.

6. The method according to claim 5, characterized in that, The rotor motion characteristics of the synchronous generator are as follows: In the formula, P e P represents the grid-connected active power. ref M represents the active reference power, M=Jω0 represents the equivalent virtual inertia, J represents the virtual inertia, ω0 represents the rated angular frequency, ω represents the adjustable angular frequency, and D represents the active reference power. i (i=1,2) represents the virtual damping, also known as the primary frequency modulation parameter, and λ is... This represents the coefficient of a fractional integral.

7. The method according to claim 5, characterized in that, The excitation voltage regulation characteristics of the synchronous generator are as follows: In the formula, E represents the regulating voltage, E0 represents the rated voltage, and k q This represents the primary voltage regulation parameter, Qe represents the grid-connected reactive power, and Q... ref This indicates the reactive power reference power.

8. The method according to claim 5, characterized in that, The method of controlling angular velocity and active power by simulating the rotor motion characteristics of a synchronous generator to output a controlled angular frequency and phase includes: The angular frequency deviation between the rated angular frequency and the actual angular frequency is proportionally amplified to generate a frequency deviation control quantity; The power deviation between the active reference power and the actual active power is superimposed with the frequency deviation control amount to generate a first superimposed signal; The first superimposed signal is adjusted by virtual damping and virtual inertia to output the controlled angular frequency and phase.

9. The method according to claim 5, characterized in that, The method of regulating voltage and reactive power by simulating the excitation voltage regulation characteristics of a synchronous generator to output a regulated voltage includes: The voltage deviation is determined based on the voltage reference value and the effective voltage value. Based on the reactive power reference power and the actual reactive power, determine the reactive power deviation; The voltage deviation and the reactive power deviation are superimposed to generate a second superimposed signal; The second superimposed signal is integrated and adjusted to output a control voltage.

10. A grid-connected control device for a water-air coupled compressed air energy storage system, characterized in that, The device includes: The first control unit is used to control the angular velocity and active power by simulating the rotor motion characteristics of a synchronous generator, so as to output the control angular frequency and phase. The second control unit is used to regulate the voltage value and reactive power by simulating the excitation voltage regulation characteristics of a synchronous generator, so as to output the regulated voltage. The signal generation unit generates an output voltage reference signal for the grid-connected inverter based on the controlled angular frequency, phase, and controlled voltage. The output voltage reference signal is used for: the grid-connected inverter to convert the DC voltage generated by the water-air coupled compressed air energy storage system into AC voltage.

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