Parallel and off-grid control method, device and medium for distributed compressed air energy storage device

Abstract

The present invention discloses a grid connection and disconnection control method, device and medium for a distributed compressed air energy storage device, including: under normal operation of the microgrid, periodically controlling the compressed air energy storage device to switch between grid connection and disconnection; when the voltage / frequency of the microgrid reaches the warning threshold, automatically controlling the compressed air energy storage device to switch between grid connection and disconnection; when the microgrid uses the energy storage device for black start, automatically controlling the compressed air energy storage device to switch between grid connection and disconnection according to a predetermined program. The method, device and medium can reduce the impact current generated during the grid connection and disconnection switching of the compressed air energy storage device and the disturbance to the microgrid and the external power grid.

Description

Technical Field

[0001] The present invention belongs to the technical field of grid connection control, and relates to a grid connection and disconnection control method, device and medium for a distributed compressed air energy storage device. Background Art

[0002] Energy storage is an important part of the future new power system. Energy storage on the user side has many functions such as peak shaving and valley filling, demand control, and emergency power supply. In the future, it can also be combined with regional distributed power sources to form a virtual power plant and participate in power market auxiliary services such as frequency modulation and voltage regulation.

[0003] Currently, the widely used electrochemical energy storage has unsafe factors such as unstable chemical properties, flammability and easy heat generation, which limit its application in some scenarios. The distributed compressed air energy storage device based on a piston-type pneumatic engine has many advantages such as small volume, easy installation, safe operation, and having moment of inertia. It can also release heat and cold during the charging and discharging processes, and is suitable for integrating into a combined cooling, heat and power microgrid to further improve energy utilization efficiency.

[0004] The distributed compressed air energy storage device based on a piston-type pneumatic engine directly connects to the microgrid using a permanent magnet synchronous generator. Currently, the design and research of the grid connection and disconnection control system for distributed energy storage devices mostly target electrochemical energy storage and adopt the grid connection method of a full-power inverter. There is almost no research on directly connecting to the grid using a rotating electrical machine, especially a permanent magnet synchronous motor. The characteristic that the permanent magnet synchronous generator itself does not have voltage regulation ability makes it easy to generate instantaneous reactive current impact during grid connection. And due to the long starting time of the rotating electrical machine, when suddenly losing the power supply of the external power grid, there is a risk of short-term power outage in the microgrid. Solving the above problems requires designing a corresponding grid connection and disconnection control system for the distributed compressed air energy storage device. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned disadvantages of the prior art, and provides a grid connection and disconnection control method, device and medium for a distributed compressed air energy storage device, which can reduce the impact current generated during the grid connection and disconnection switching of the compressed air energy storage device and the disturbance to the microgrid and the external power grid.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] On the one hand, the grid connection and disconnection control method for the distributed compressed air energy storage device of the present invention includes:

[0008] Under the normal operation of the microgrid, timely control the grid connection and disconnection switching of the compressed air energy storage device according to a predetermined program;

[0009] When the voltage / frequency of the microgrid reaches the warning threshold, automatically control the grid connection and disconnection switching of the compressed air energy storage device;

[0010] When the microgrid uses the energy storage device for black start, the compressed air energy storage device is automatically controlled according to a predetermined program to perform the switching between grid connection and off-grid.

[0011] A further improvement of the grid connection and off-grid control method for the distributed compressed air energy storage device of the present invention lies in:

[0012] Furthermore, the distributed compressed air energy storage device includes a compressed air input pipeline, a pneumatic engine valve, a pneumatic engine, a permanent magnet synchronous generator, a grid connection breaker, a high-voltage side bus of the microgrid, a low-voltage side bus of the microgrid, a self-provided power bus, shunt capacitors, a tie breaker, an outgoing line breaker, and a microgrid load;

[0013] The outlet of the compressed air input pipeline is connected to the inlet of the pneumatic engine through the pneumatic engine valve. The output shaft of the pneumatic engine is connected to the drive shaft of the permanent magnet synchronous generator. The output end of the permanent magnet synchronous generator is connected to the self-provided power bus through the grid connection breaker. The self-provided power bus is connected to the low-voltage side bus of the microgrid. The self-provided power bus is connected to the power supply interface of the air compressor through a first breaker. The shunt capacitors are connected to the low-voltage side bus of the microgrid. The high-voltage side bus of the microgrid is connected to the low-voltage side bus of the microgrid through a transformer. The high-voltage side bus of the microgrid is connected to the external power grid through the tie breaker. The low-voltage side bus of the microgrid is connected to the microgrid load through the outgoing line breaker.

[0014] Furthermore, under the normal operation condition of the microgrid, the process of periodically controlling the compressed air energy storage device to perform the switching from off-grid to grid connection is as follows:

[0015] Control the permanent magnet synchronous generator to start no-load under the drive of the pneumatic engine, and adjust the output voltage frequency of the permanent magnet synchronous generator to be constantly a preset frequency;

[0016] Measure the voltage amplitude difference ΔV at both ends of the grid connection breaker, put into the shunt adjustable reactor, and adjust the reactance value of the shunt adjustable reactor to make the voltage amplitudes at both ends of the grid connection breaker equal;

[0017] Measure the voltage phase difference Δθ at both ends of the grid connection breaker, and adjust the output voltage phase of the permanent magnet synchronous generator to make the voltage phase difference at both ends of the grid connection breaker zero;

[0018] Control the grid connection breaker to close;

[0019] Gradually adjust the reactance value of the shunt adjustable reactor to the maximum, and then cut off the shunt adjustable reactor;

[0020] Adjust the output of the permanent magnet synchronous generator to gradually increase from 0 to the given value of the daily power generation plan curve at a preset rate of change. During the adjustment process, connect shunt capacitors. By adjusting the shunt capacitors, minimize the output reactive power of the permanent magnet synchronous generator.

[0021] Further, under normal operation of the microgrid, the process of timing control for the compressed air energy storage device to switch from grid-connected to off-grid is as follows:

[0022] Adjust the output of the permanent magnet synchronous generator to gradually decrease to 0 at a preset rate of change. During the adjustment process, by adjusting the shunt capacitors, minimize the output reactive power of the permanent magnet synchronous generator;

[0023] By adjusting the shunt capacitors or shunt adjustable reactors, make the output reactive power of the permanent magnet synchronous generator equal to 0;

[0024] Control the grid-connected breaker to open;

[0025] Close the pneumatic engine valve, so that the rotor speed of the permanent magnet synchronous generator gradually becomes 0 under the damping effect.

[0026] Further, when the microgrid voltage / frequency reaches the warning threshold, during the process of automatically controlling the compressed air energy storage device to switch between grid-connected and off-grid, when the microgrid voltage deviation or frequency deviation touches the low set value (|Δflow| or |ΔVlow|), then control the pneumatic engine to drive the permanent magnet synchronous generator to start and enter the hot standby state.

[0027] Further, when the microgrid voltage / frequency reaches the warning threshold, during the process of automatically controlling the compressed air energy storage device to switch between grid-connected and off-grid, when the microgrid voltage deviation or frequency deviation continuously increases to touch the high set value (|Δfhigh| or |ΔVhigh|), then close the grid-connected breaker and open the tie breaker.

[0028] Further, when the microgrid uses the energy storage device for black start, the process of automatically controlling the compressed air energy storage device to switch from off-grid to grid-connected according to a predetermined program is as follows:

[0029] When it is detected that the microgrid loses voltage and continues to delay for t3, open the tie breaker, and then open the outgoing line breaker to cut off all the microgrid loads on the low-voltage side bus of the microgrid;

[0030] Control the pneumatic engine to drive the permanent magnet synchronous generator to start without load, and adjust the pneumatic engine so that the outlet voltage frequency of the permanent magnet synchronous generator is constantly the rated frequency;

[0031] Close the grid-connected breaker;

[0032] According to the importance order of the loads in the microgrid, the outgoing line circuit breakers are closed in sequence to restore the power supply to each load in the microgrid.

[0033] Furthermore, when the microgrid uses the energy storage device for black start, the process of automatically controlling the compressed air energy storage device to switch from grid-connected to off-grid according to a predetermined program is as follows:

[0034] When it is detected that the external grid voltage has recovered, the shunt capacitor is adjusted to make the voltage of the microgrid equal to the voltage of the external grid;

[0035] Control the tie circuit breaker to perform quasi-synchronous closing;

[0036] Adjust the output of the permanent magnet synchronous generator to gradually decrease to 0 at a preset rate of change. During the adjustment process, by adjusting the shunt capacitor, the output reactive power of the permanent magnet synchronous generator is minimized;

[0037] By adjusting the shunt capacitor or the shunt adjustable reactor, make the output reactive power of the permanent magnet synchronous generator 0;

[0038] Disconnect the grid-connected circuit breaker;

[0039] Close the pneumatic engine valve, and the speed of the rotor of the permanent magnet synchronous generator gradually becomes 0 under the damping effect.

[0040] In a second aspect of the present invention, the computer device described in the present invention includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the on-off grid control method for the distributed compressed air energy storage device are implemented.

[0041] In a third aspect of the present invention, the computer-readable storage medium described in the present invention stores a computer program, characterized in that when the computer program is executed by a processor, the steps of the on-off grid control method for the distributed compressed air energy storage device are implemented.

[0042] The present invention has the following beneficial effects:

[0043] When the on-off grid control method, device, and medium for the distributed compressed air energy storage device described in the present invention are specifically operated, according to the characteristics of the distributed compressed air energy storage device, it is divided into the normal operation of the microgrid, the microgrid voltage / frequency reaching the warning threshold, and the microgrid using the energy storage device for black start. For the above three working conditions, corresponding control methods are adopted to realize the automatic control of the switching between grid-connected and off-grid of the compressed air energy storage device, thereby reducing the impact current generated during the grid-connected and off-grid switching of the compressed air energy storage device and the disturbance to the microgrid and the external grid, and the practicability is extremely strong. Description of the Drawings

[0044] The accompanying drawings forming a part of this invention are used to provide a further understanding of the invention. The schematic embodiments and descriptions thereof of the invention are used to explain the invention and shall not unduly limit the invention. In the drawings:

[0045] Figure 1 is the schematic diagram of the present invention.

[0046] Wherein, M is a pneumatic engine, G is a permanent magnet synchronous generator, L is a shunt adjustable reactor, B1 is the high-voltage side bus of the microgrid, B2 is the low-voltage side bus of the microgrid, B3 is the self-provided power bus, C is a shunt capacitor, K1 is a grid-connection circuit breaker, K2 is a tie circuit breaker, and K3-Kn are outgoing line circuit breakers. Detailed implementation manners

[0047] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the present invention disclosed. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts disclosed in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0048] The structural schematic diagrams according to the disclosed embodiments of the present invention are shown in the drawings. These drawings are not drawn to scale, and for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the drawings and their relative sizes and positional relationships are only exemplary, and may actually deviate due to manufacturing tolerances or technical limitations. Those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0049] Embodiment 1

[0050] Reference Figure 1, the present invention discloses a grid-connected and off-grid control method for a distributed compressed air energy storage device. The distributed compressed air energy storage device includes a compressed air input pipeline, a pneumatic engine valve, a pneumatic engine M, a permanent magnet synchronous generator G, a grid-connected breaker K1, a low-voltage bus B1 of a microgrid, a high-voltage bus B2 of the microgrid, a self-provided power supply bus B3, a shunt capacitor C, a tie breaker K2, outgoing line breakers K1-Kn, and a microgrid load; the outlet of the compressed air input pipeline is connected to the inlet of the pneumatic engine M through the pneumatic engine valve, the output shaft of the pneumatic engine M is connected to the drive shaft of the permanent magnet synchronous generator G, the output end of the permanent magnet synchronous generator G is connected to the self-provided power supply bus B3 through the grid-connected breaker K1, the self-provided power supply bus B3 is connected to the low-voltage bus B1 of the microgrid, the self-provided power supply bus B3 is connected to the power supply interface of the air compressor through a breaker, the high-voltage bus B1 of the microgrid is grounded after passing through the shunt capacitor C, the low-voltage bus B1 of the microgrid is connected to the high-voltage bus B2 of the microgrid through a transformer, the high-voltage bus B2 of the microgrid is connected to the external power grid through the tie breaker K2, and the low-voltage bus B1 of the microgrid is connected to the microgrid load through the outgoing line breakers K1-Kn.

[0051] The grid-connected and off-grid control method for the distributed compressed air energy storage device of the present invention includes:

[0052] 1) Under normal operation of the microgrid, the grid connection and off-grid of the compressed air energy storage device are controlled regularly:

[0053] Among them, the specific process from off-grid to grid connection is as follows:

[0054] 111) The permanent magnet synchronous generator G is started without load driven by the pneumatic engine M, and the control system adjusts the output voltage frequency of the permanent magnet synchronous generator G to be constantly 50 Hz.

[0055] 112) The voltage measurement module measures the voltage amplitude difference ΔV at both ends of the grid-connected breaker K1. The control system inputs the shunt adjustable reactor L and adjusts the reactance value of the shunt adjustable reactor L to make the voltage amplitudes at both ends of the grid-connected breaker K1 equal, that is, ΔV = 0.

[0056] 113) The phase measurement module measures the voltage phase difference Δθ at both ends of the grid-connected breaker K1. The control system adjusts the output voltage phase of the permanent magnet synchronous generator G to make the voltage phase difference at both ends of the grid-connected breaker K1 zero, that is, Δθ = 0.

[0057] 114) The control system issues a remote control signal to close the grid-connected breaker K1.

[0058] 115) The control system gradually adjusts the reactance value of the shunt adjustable reactor L to the maximum, and then removes the shunt adjustable reactor L.

[0059] 116) The control system adjusts the output of the permanent magnet synchronous generator G to gradually increase from 0 at a preset rate of change until the given value of the daily power generation plan curve. During the adjustment process, the control system connects the shunt capacitor C and, by adjusting the shunt capacitor C, minimizes the output inductive reactive power of the permanent magnet synchronous generator G.

[0060] 12) The specific process from grid connection to grid disconnection is as follows:

[0061] 121) The control system adjusts the output of the permanent magnet synchronous generator G to gradually decrease at a preset rate of change until it reaches 0. During the adjustment process, the control system minimizes the output inductive reactive power of the permanent magnet synchronous generator G by adjusting the shunt capacitor C.

[0062] 122) The control system adjusts the shunt capacitor C or the shunt adjustable reactor L to make the output inductive reactive power of the permanent magnet synchronous generator G equal to 0.

[0063] 123) The control system issues a remote control signal to disconnect the grid connection breaker K1.

[0064] 124) The control system closes the pneumatic engine valve, and the rotor of the permanent magnet synchronous generator G gradually stops rotating under the damping effect until the speed reaches 0.

[0065] 2) When the microgrid voltage / frequency reaches the warning threshold, the control system automatically performs grid connection and disconnection control.

[0066] During the design process of the microgrid, when the voltage or frequency deviates from the normal value by more than a certain threshold, the microgrid will disconnect from the external power grid and switch to island operation. Since it takes a certain amount of time for the energy storage device to start from cold standby to full operation, if the voltage and frequency of the external power grid change rapidly during the startup process, it may trigger low-frequency and undervoltage protection actions, resulting in power loss of the microgrid. To reduce the risk of the above situation, the present invention proposes a startup control strategy for a compressed air energy storage device with two startup set values (|Δflow|, |Δfhigh|, |ΔVlow|, |ΔVhigh|). When the microgrid voltage deviation or frequency deviation reaches the low set value (|Δflow| or |ΔVlow|), the pneumatic engine M in the compressed air energy storage device drives the permanent magnet synchronous generator G to start and enter the hot standby state. When the microgrid voltage deviation or frequency deviation continues to increase and reaches the high set value (|Δfhigh| or |ΔVhigh|), the compressed air energy storage device is immediately connected to the microgrid, and the microgrid immediately disconnects from the external power grid. When the microgrid voltage deviation or frequency deviation gradually decreases, after a certain delay less than the low set value, the compressed air energy storage device switches from hot standby to cold standby state.

[0067] 21) The specific process from grid disconnection to grid connection is as follows:

[0068] 211) When it is monitored that the microgrid voltage (or frequency deviation) reaches the low starting setting value |ΔV low | (or |Δf low |) and lasts for a preset delay t1, the control system controls the pneumatic engine M to drive the permanent magnet synchronous generator G to start without load, and the control system adjusts the output voltage frequency of the permanent magnet synchronous generator G to be constantly 50 Hz.

[0069] 212) The voltage measurement module measures the voltage amplitude difference at both ends of the grid-connected breaker K1. The control system inserts the shunt adjustable reactor L and, by adjusting the shunt adjustable reactor L, makes the voltage amplitudes at both ends of the grid-connected breaker K1 equal.

[0070] 213) The phase measurement module measures the voltage phase difference at both ends of the grid-connected breaker K1. The control system controls the output voltage phase of the permanent magnet synchronous generator G to make the voltage phase difference at both ends of the grid-connected breaker K1 zero.

[0071] 214) When it is monitored that the microgrid voltage (or frequency deviation) reaches the high starting setting value |ΔV high | (or |Δf high |) and lasts for a preset delay t2, the control system issues a remote control signal to close the grid-connected breaker K1 and simultaneously open the tie breaker K2.

[0072] 215) The control system adjusts the speed of the pneumatic engine M to make the microgrid voltage frequency constantly the preset frequency 50 Hz. At the same time, the control system removes the shunt adjustable reactor L and inserts the shunt capacitor C, and by adjusting the shunt capacitor C, makes the microgrid voltage amplitude constantly the preset value V0.

[0073] 22) The specific process from grid connection to grid disconnection is as follows:

[0074] 221) When it is monitored that the microgrid voltage or frequency deviation is less than the low starting setting value |ΔV low | (or |Δf low |) and lasts for a preset delay t1', the control system adjusts the shunt capacitor C to make the microgrid voltage equal to the external grid voltage.

[0075] 222) The control system issues a remote control signal and monitors the voltage phases of the microgrid and the external grid to make the tie breaker K2 perform a quasi-synchronous closing.

[0076] 223) The control system adjusts the output of the permanent magnet synchronous generator G to gradually decrease at a preset rate of change until it is zero. Among them, during the adjustment process, the control system, by adjusting the shunt capacitor C, makes the output inductive reactive power of the permanent magnet synchronous generator G as small as possible.

[0077] 224) The control system adjusts the shunt capacitor C or the shunt adjustable reactor L to make the output inductive reactive power of the permanent magnet synchronous generator G zero.

[0078] 225) The control system sends a remote control signal to open the grid-connected breaker K1.

[0079] 226) The control system closes the pneumatic engine valve, and the speed of the rotor of the permanent magnet synchronous generator G gradually becomes zero under the damping effect.

[0080] 3) When the microgrid uses the energy storage device for black start, the control system automatically performs grid connection and disconnection control according to a predetermined program.

[0081] 31) The specific process from grid disconnection to grid connection is as follows:

[0082] 311) When it is detected that the microgrid voltage is lost and the continuous delay is t3, the control system sends a remote control signal to open the tie breaker K2, and then opens the outgoing line breakers K3 - Kn to cut off all the microgrid loads on the microgrid bus.

[0083] 312) The control system controls the pneumatic engine M to drive the permanent magnet synchronous generator G to start without load, and the control system adjusts the pneumatic engine M so that the outlet voltage frequency of the permanent magnet synchronous generator G is kept constant at 50 Hz.

[0084] 313) The control system sends a remote control signal to close the grid-connected breaker K1.

[0085] 314) According to the load importance order in the microgrid (previously input into the control system), the corresponding outgoing line breakers K3 - Kn on the microgrid bus are closed one by one to gradually restore power supply to the loads.

[0086] 32) The specific process from grid connection to grid disconnection is as follows:

[0087] 321) When it is detected that the external grid voltage is restored, the control system adjusts the shunt capacitor C to make the microgrid voltage equal to the external grid voltage.

[0088] 322) The control system sends a quasi-synchronous closing execution signal to the tie breaker K2 to make the tie breaker K2 perform quasi-synchronous closing.

[0089] 323) The control system adjusts the output of the permanent magnet synchronous generator G to gradually decrease at a preset rate of change until it becomes zero. Among them, during the adjustment process, the control system adjusts the shunt capacitor C to make the output inductive reactive power of the permanent magnet synchronous generator G as small as possible.

[0090] 324) The control system adjusts the shunt capacitor C or the shunt adjustable reactor L to make the output inductive reactive power of the permanent magnet synchronous generator G zero.

[0091] 326) The control system issues a remote control signal to disconnect the grid-connected breaker K1.

[0092] 327) Close the pneumatic engine valve, and the speed of the rotor of the permanent magnet synchronous generator G gradually becomes 0 under the damping effect.

[0093] The present invention has the following characteristics:

[0094] The present invention minimizes the reactive inrush current during grid connection by adjusting the terminal voltage of the permanent magnet synchronous generator G under no-load conditions. The present invention sets two high and low starting set values for the distributed compressed air energy storage device according to the voltage and frequency offsets of the microgrid, greatly reducing the risk of power outage of the microgrid due to external grid disturbances. The grid connection method of the present invention during the black start of the microgrid avoids the slow acceleration of the generator speed during load starting.

[0095] Embodiment 2

[0096] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the on-grid and off-grid control method of the distributed compressed air energy storage device. For example, it includes: under normal operation of the microgrid, periodically controlling the compressed air energy storage device to switch between on-grid and off-grid; when the voltage / frequency of the microgrid reaches the warning threshold, automatically controlling the compressed air energy storage device to switch between on-grid and off-grid; when the microgrid uses the energy storage device for black start, automatically controlling the compressed air energy storage device to switch between on-grid and off-grid according to a predetermined program. Among them, the memory may include internal memory, such as high-speed random access memory, and may also include non-volatile memory, such as at least one disk memory, etc.; the processor, network interface, and memory are interconnected through an internal bus, which can be an Industry Standard Architecture bus, a Peripheral Component Interconnect standard bus, an Extended Industry Standard Architecture bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. The memory is used to store programs. Specifically, the program may include program code, and the program code includes computer operation instructions. The memory may include internal memory and non-volatile memory and provide instructions and data to the processor.

[0097] Embodiment 3

[0098] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the steps of the on-grid and off-grid control method of the distributed compressed air energy storage device. For example, it includes: under normal operation of the microgrid, regularly controlling the compressed air energy storage device to switch between on-grid and off-grid; when the voltage / frequency of the microgrid reaches the warning threshold, automatically controlling the compressed air energy storage device to switch between on-grid and off-grid; when the microgrid uses the energy storage device for black start, automatically controlling the compressed air energy storage device to switch between on-grid and off-grid according to a predetermined program. Specifically, the computer-readable storage medium includes but is not limited to, for example, volatile memory and / or non-volatile memory. The volatile memory may include random access memory (RAM) and / or cache memory, etc. The non-volatile memory may include read-only memory (ROM), hard disk, flash memory, optical disc, magnetic disk, etc.

[0099] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0100] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the flows and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the specified functions in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0101] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device implements the specified functions in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0102] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are performed on the computer or other programmable apparatus to generate a computer-implemented process, thereby providing instructions for implementing the functions specified in one process or multiple processes and / or boxes Figure 1 one process or multiple processes and / or boxes Figure 1 steps for the functions specified in one box or multiple boxes.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific embodiments of the present invention. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A method for controlling a distributed compressed air energy storage device on and off the grid, characterized in that: include: Under normal operation of the microgrid, the compressed air energy storage device is controlled in a timely manner to switch between grid connection and off-grid according to a predetermined control strategy; When the voltage / frequency of the microgrid reaches the warning threshold, the compressed air energy storage device is automatically controlled to switch between grid connection and off-grid connection; When the microgrid uses the energy storage device for black start, the compressed air energy storage device is automatically controlled to switch between grid connection and off-grid according to a predetermined program; The distributed compressed air energy storage device includes a compressed air input pipeline, a pneumatic engine valve, a pneumatic engine (M), a permanent magnet synchronous generator (G), a grid-connected circuit breaker (K1), a microgrid low-voltage side bus (B1), a microgrid high-voltage side bus (B2), a self-provided power supply bus (B3), a parallel capacitor (C), a connecting circuit breaker (K2), an outgoing line circuit breaker (K3-Kn) and a microgrid load; The outlet of the compressed air input pipeline is connected to the inlet of the pneumatic engine (M) through the pneumatic engine valve, the output shaft of the pneumatic engine (M) is connected to the driving shaft of the permanent magnet synchronous generator (G), the output end of the permanent magnet synchronous generator (G) is connected to the self-supplied power bus (B3) through the grid-connected circuit breaker (K1), the self-supplied power bus (B3) is connected to the low-voltage side bus (B1) of the microgrid, the self-supplied power bus (B3) is connected to the power interface of the air compressor through the first circuit breaker, the shunt capacitor (C) is connected between the low-voltage side bus (B1) of the microgrid and the ground, the low-voltage side bus (B1) of the microgrid is connected to the high-voltage side bus (B2) of the microgrid through the transformer, the high-voltage side bus (B2) of the microgrid is connected to the external power grid through the connecting circuit breaker (K2), and the low-voltage side bus (B1) of the microgrid is connected to a plurality of microgrid loads through the outgoing circuit breakers (K3-Kn); Under normal operation of the microgrid, the switching process of the compressed air energy storage device from off-grid to grid-connected is controlled in a timely manner according to the predetermined control strategy: Controlling the permanent magnet synchronous generator (G) to start at no load under the drive of the pneumatic engine (M), and adjusting the output voltage frequency of the permanent magnet synchronous generator (G) to be constant at a preset frequency; Measuring a voltage amplitude difference ΔV at both ends of a grid-connected circuit breaker (K1), inputting a parallel adjustable reactor (L), and adjusting the reactance value of the parallel adjustable reactor (L) to make the voltage amplitudes at both ends of the grid-connected circuit breaker (K1) equal, wherein the adjustable reactor (L) is connected to the output side of a permanent magnet synchronous generator (G); The voltage phase difference Δθ at both ends of the grid-connected circuit breaker (K1) is measured, and the output voltage phase of the permanent magnet synchronous generator (G) is adjusted so that the voltage phase difference at both ends of the grid-connected circuit breaker (K1) is 0; Control the grid-connected circuit breaker (K1) to close; Gradually adjust the reactance value of the parallel adjustable reactor (L) to the maximum, and then cut off the parallel adjustable reactor (L); The output of the permanent magnet synchronous generator (G) is adjusted to gradually increase from 0 to a given value of the daily power generation plan curve at a preset change rate, wherein, during the adjustment process, a parallel capacitor (C) is put into use, and the output inductive reactive power of the permanent magnet synchronous generator (G) is minimized by adjusting the parallel capacitor (C).

2. The on-grid and off-grid control method of a distributed compressed air energy storage device according to claim 1, characterized in that: Under normal operation of the microgrid, the switching process of the compressed air energy storage device from grid-connected to off-grid is as follows: The output of the permanent magnet synchronous generator (G) is adjusted to gradually decrease to 0 at a preset change rate, wherein, during the adjustment process, the output inductive reactive power of the permanent magnet synchronous generator (G) is minimized by adjusting the parallel capacitor (C); By adjusting the parallel capacitor (C) or the parallel adjustable reactor (L), the output inductive reactive power of the permanent magnet synchronous generator (G) is made 0; Control the grid-connected circuit breaker (K1) to disconnect; The air engine valve is closed, so that the rotor speed of the permanent magnet synchronous generator (G) gradually decreases to 0 under the action of damping.

3. The on-grid and off-grid control method of a distributed compressed air energy storage device according to claim 1, characterized in that: When the voltage / frequency of the microgrid reaches the warning threshold, the compressed air energy storage device is automatically controlled to switch between grid-connected and off-grid. When the voltage deviation or frequency deviation of the microgrid reaches a low set value (|Δflow| or |ΔVlow|), the pneumatic engine (M) is controlled to drive the permanent magnet synchronous generator (G) to start and enter the hot standby state.

4. The on-grid and off-grid control method of a distributed compressed air energy storage device according to claim 1, characterized in that: When the voltage / frequency of the microgrid reaches the warning threshold, the compressed air energy storage device is automatically controlled to switch between grid-connected and off-grid. When the pneumatic engine (M) and the permanent magnet synchronous generator (G) are in hot standby state, if the voltage deviation or frequency deviation of the microgrid continues to increase until it reaches a high set value (|Δfhigh| or |ΔVhigh|), the grid-connected circuit breaker (K1) is closed and the connecting circuit breaker (K2) is opened.

5. The on-grid and off-grid control method of a distributed compressed air energy storage device according to claim 1, characterized in that: When the microgrid uses the energy storage device for black start after power failure, the switching process of the compressed air energy storage device from off-grid to on-grid is automatically controlled according to a predetermined program: When the microgrid is detected to be de-voltaged and the delay is t3, the interconnection circuit breaker (K2) is disconnected, and then the outgoing circuit breakers (K3-Kn) are disconnected to cut off all microgrid loads on the low-voltage side bus (B1) of the microgrid; Controlling the pneumatic engine (M) to drive the permanent magnet synchronous generator (G) to start at no load, and adjusting the pneumatic engine (M) so that the outlet voltage frequency of the permanent magnet synchronous generator (G) is constant to the rated frequency; Close the grid circuit breaker (K1); According to the order of importance of the loads in the microgrid, the outgoing line circuit breakers (K3-Kn) are closed in sequence to gradually restore the power supply to each microgrid load.

6. The on-grid and off-grid control method of a distributed compressed air energy storage device according to claim 1, characterized in that: When the microgrid uses the energy storage device for black start after power failure, the compressed air energy storage device is automatically controlled according to a predetermined program to switch from grid-connected to off-grid: When the voltage of the external grid is detected to be restored, the parallel capacitor (C) is adjusted to make the voltage of the microgrid equal to that of the external grid; Control the interconnecting circuit breaker (K2) to perform quasi-synchronous closing; The output of the permanent magnet synchronous generator (G) is adjusted to gradually decrease to 0 at a preset change rate, wherein, during the adjustment process, the output inductive reactive power of the permanent magnet synchronous generator (G) is minimized by adjusting the parallel capacitor (C); By adjusting the parallel capacitor (C) or the parallel adjustable reactor (L), the output inductive reactive power of the permanent magnet synchronous generator (G) is made 0; Disconnect the grid circuit breaker (K1); When the air engine valve is closed, the rotor speed of the permanent magnet synchronous generator (G) gradually decreases to 0 under the action of damping.

7. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the on-grid and off-grid control method of the distributed compressed air energy storage device as described in any one of claims 1-6 are implemented.

8. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the on-grid and off-grid control method of a distributed compressed air energy storage device as described in any one of claims 1 to 6 are implemented.

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