Grid-connected and off-grid control method and equipment of distributed compressed air energy storage device and medium

Abstract

The invention discloses a grid-connected and off-grid control method and equipment for a distributed compressed air energy storage device and a medium, and the method comprises the steps: controlling the compressed air energy storage device to carry out grid-connected and off-grid switching at regular time under the normal operation condition of a micro-grid; when the voltage / frequency of the micro-grid reaches a warning threshold value, the compressed air energy storage device is automatically controlled to switch between grid connection and grid disconnection; when the micro-grid utilizes the energy storage device to perform black start, the compressed air energy storage device is automatically controlled to perform grid-connected and off-grid switching according to a preset program, and the method, the equipment and the medium can reduce impact current generated when the compressed air energy storage device performs grid-connected and off-grid switching and disturbance to the micro-grid and the external power grid.

Description

Technical Field

[0001] The present invention belongs to the technical field of grid-connected control, and relates to a grid-connected and off-grid control method, equipment 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. User-side energy storage has many functions such as peak shifting, 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 and voltage regulation.

[0003] The widely used electrochemical energy storage has unsafe factors such as unstable chemical properties, flammability and heat generation, which limits its application in certain scenarios. The distributed compressed air energy storage device based on the piston pneumatic engine has many advantages such as small size, easy installation, safe operation, and rotational inertia. It can also release heat and cold during the charging and discharging process, which is suitable for integration into the combined heat, cooling and power microgrid to further improve energy utilization efficiency.

[0004] The distributed compressed air energy storage device based on the piston pneumatic engine adopts a permanent magnet synchronous generator to be directly connected to the microgrid. At present, the design and research of the on-grid and off-grid control system of the distributed energy storage device is mostly aimed at electrochemical energy storage, and the grid connection method of the full-power inverter is adopted. There is almost no research on the direct grid connection using rotating motors, especially permanent magnet synchronous motors. The permanent magnet synchronous generator itself does not have the characteristic of voltage regulation, which makes it easy to generate instantaneous reactive current shock when it is connected to the grid. In addition, due to the long start-up time of the rotating motor, when the external power grid is suddenly lost, the microgrid is at risk of short-term power outage. To solve the above problems, it is necessary to design the on-grid and off-grid control system of the corresponding distributed compressed air energy storage device. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method, device and medium for controlling the on-grid and off-grid operation of a distributed compressed air energy storage device. The method, device and medium can reduce the impact current generated when the compressed air energy storage device is switched on and off the grid and the disturbance to the microgrid and the external power grid.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] In one aspect of the present invention, the on-grid and off-grid control method of the distributed compressed air energy storage device of the present invention comprises:

[0008] Under normal operation of the microgrid, the compressed air energy storage device is controlled in a timely manner according to a predetermined program to switch between grid connection and off-grid operation;

[0009] 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;

[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 switch between grid connection and off-grid operation.

[0011] The on-grid and off-grid control method of the distributed compressed air energy storage device of the present invention is further improved in that:

[0012] Further, 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-connected circuit breaker, a microgrid high-voltage side bus, a microgrid low-voltage side bus, a self-provided power supply bus, a shunt capacitor, a tie circuit breaker, an outgoing line circuit 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-supplied power bus through the grid-connected circuit breaker, the self-supplied power bus is connected to the low-voltage side bus of the microgrid, the self-supplied power bus is connected to the power interface of the air compressor through the first circuit breaker, the parallel capacitor is 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 the transformer, the high-voltage side bus of the microgrid is connected to the external power grid through the connecting circuit breaker, and the low-voltage side bus of the microgrid is connected to the microgrid load through the outgoing circuit breaker.

[0014] Furthermore, under normal operation of the microgrid, the switching process of timing control of the compressed air energy storage device from off-grid to grid-connected is:

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

[0016] Measure the voltage amplitude difference ΔV at both ends of the grid-connected circuit breaker, put in parallel adjustable reactor, and adjust the reactance value of the parallel adjustable reactor to make the voltage amplitude at both ends of the grid-connected circuit breaker equal;

[0017] Measure the voltage phase difference Δθ at both ends of the grid-connected circuit 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-connected circuit breaker 0;

[0018] Control the closing of the grid-connected circuit breaker;

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

[0020] The output of the permanent magnet synchronous generator is adjusted to gradually increase from 0 to a given value of the daily power generation plan curve at a preset change rate. During the adjustment process, a parallel capacitor is put into use. By adjusting the parallel capacitor, the output inductive reactive power of the permanent magnet synchronous generator is minimized.

[0021] Furthermore, under normal operation of the microgrid, the switching process of timing control of the compressed air energy storage device from grid-connected to off-grid is:

[0022] The output of the permanent magnet synchronous generator 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 is minimized by adjusting the parallel capacitor;

[0023] By adjusting the parallel capacitor or the parallel adjustable reactor, the output inductive reactive power of the permanent magnet synchronous generator is made 0;

[0024] Control the grid-connected circuit breaker to disconnect;

[0025] The air engine valve is closed, so that the rotor speed of the permanent magnet synchronous generator gradually decreases to 0 under the action of damping.

[0026] Furthermore, 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 is controlled to drive the permanent magnet synchronous generator to start and enter the hot standby state.

[0027] Furthermore, 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 continues to increase to reach a high set value (|Δfhigh| or |ΔVhigh|), the grid-connected circuit breaker is closed and the connecting circuit breaker is disconnected.

[0028] Furthermore, when the microgrid uses the energy storage device for black start, the switching process of automatically controlling the compressed air energy storage device from off-grid to on-grid is as follows:

[0029] When the microgrid is detected to lose voltage and the delay is t3, the connecting circuit breaker is disconnected, and then the outgoing circuit breaker is disconnected to cut off all 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 at no load, and adjust the pneumatic engine so that the outlet voltage frequency of the permanent magnet synchronous generator is constant at the rated frequency;

[0031] Close the grid-connected circuit breaker;

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

[0033] Furthermore, 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 switch from grid-connected to off-grid:

[0034] When the voltage of the external grid is detected to be restored, the parallel capacitor is adjusted to make the voltage of the microgrid equal to the voltage of the external grid;

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

[0036] The output of the permanent magnet synchronous generator 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 is minimized by adjusting the parallel capacitor;

[0037] By adjusting the parallel capacitor or the parallel adjustable reactor, the output inductive reactive power of the permanent magnet synchronous generator is made 0;

[0038] Disconnect the grid circuit breaker;

[0039] When the air engine valve is closed, the rotor speed of the permanent magnet synchronous generator gradually decreases to 0 under the action of damping.

[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, and the processor implements the steps of the on-grid and off-grid control method of the distributed compressed air energy storage device when executing the computer program.

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

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

[0043] The distributed compressed air energy storage device on-grid and off-grid control method, device and medium described in the present invention are divided into normal operation of the microgrid, the voltage / frequency of the microgrid reaching the warning threshold and the black start of the microgrid using the energy storage device according to the characteristics of the distributed compressed air energy storage device during specific operation. For the above three working conditions, corresponding control methods are adopted to realize automatic control of the switching between on-grid and off-grid of the compressed air energy storage device, thereby reducing the impact current generated when the compressed air energy storage device is switched on-grid and off-grid and the disturbance to the microgrid and the external power grid, and the practicability is extremely strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

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

[0046] Among them, M is a pneumatic engine, G is a permanent magnet synchronous generator, L is a parallel adjustable reactor, B1 is a microgrid high-voltage side bus, B2 is a microgrid low-voltage side bus, B3 is a self-contained power supply bus, C is a parallel capacitor, K1 is a grid-connected circuit breaker, K2 is a connecting circuit breaker, and K3-Kn are outgoing circuit breakers. DETAILED DESCRIPTION

[0047] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only an embodiment of a part of the present invention, not all embodiments, and is not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concepts disclosed in the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

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

[0049] Embodiment 1

[0050] refer to Figure 1The present invention discloses a method for controlling the grid connection and off-grid connection of a distributed compressed air energy storage device, wherein the distributed compressed air energy storage device comprises 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 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, and the output shaft of the pneumatic engine M is connected to the permanent magnet synchronous generator The drive shaft of the motor G is connected, 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 a circuit breaker, the high-voltage side bus B1 of the microgrid is grounded after a parallel capacitor C, the low-voltage side bus B1 of the microgrid is connected to the high-voltage side bus B2 of the microgrid through a 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 the microgrid load through the outgoing line circuit breaker K1-Kn.

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

[0052] 1) Under normal operation of the microgrid, the compressed air energy storage device is regularly controlled to be connected and disconnected from the grid:

[0053] The specific process from off-grid to grid-connected is as follows:

[0054] 111) The permanent magnet synchronous generator G is started at no-load driven by the pneumatic engine M, and the control system adjusts the outlet voltage frequency of the permanent magnet synchronous generator G to be constant at 50 Hz.

[0055] 112) The voltage measurement module measures the voltage amplitude difference ΔV at both ends of the grid-connected circuit breaker K1, and the control system puts the parallel adjustable reactor L into operation and adjusts 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, that is, ΔV=0.

[0056] 113) The phase measurement module measures the voltage phase difference Δθ across the grid-connected circuit breaker K1, and the control system adjusts the output voltage phase of the permanent magnet synchronous generator G so that the voltage phase difference across the grid-connected circuit breaker K1 is 0, that is, Δθ=0.

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

[0058] 115) The control system gradually adjusts the reactance value of the parallel adjustable reactor L to the maximum, and then cuts off the parallel 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 it reaches a given value of the daily power generation plan curve. During the adjustment process, the control system puts the parallel capacitor C into operation and adjusts the parallel capacitor C to make the output inductive reactive power of the permanent magnet synchronous generator G as small as possible.

[0060] 12) The specific process from grid connection to off-grid connection 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 adjusts the parallel capacitor C to make the output inductive reactive power of the permanent magnet synchronous generator G as small as possible.

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

[0063] 123) The control system sends a remote control signal to disconnect the grid-connected circuit breaker K1.

[0064] 124) The control system closes the air engine valve, and the rotor speed of the permanent magnet synchronous generator G gradually decreases to 0 under the action of damping.

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

[0066] In the process of microgrid design, when the normal value of voltage or frequency deviation exceeds a certain threshold, the microgrid will disconnect from the external power grid and switch to island operation. It takes a certain amount of time for the energy storage device to start from cold standby. During the startup process, if the voltage and frequency of the external power grid change rapidly, it may trigger low-frequency and undervoltage protection actions, causing the microgrid to lose power. In order 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 high and low startup constants (|Δflo w|, |Δfhigh|, |ΔVlow|, |ΔVhigh|). When the voltage deviation or frequency deviation of the microgrid reaches a low constant (|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 voltage offset or frequency offset of the microgrid continues to increase to reach a high set value (|Δfhigh| or |ΔVhigh|), the compressed air energy storage device is immediately incorporated into the microgrid, and the microgrid is immediately disconnected from the external grid; when the voltage offset or frequency offset of the microgrid 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.

[0067] 21) The specific process from off-grid to grid-connected is:

[0068] 211) When the voltage (or frequency deviation) of the microgrid reaches the low starting value of the compressed air energy storage device |ΔV low |(or |Δf low |) and continues for the preset delay t1, the control system controls the pneumatic engine M to drive the permanent magnet synchronous generator G to start at no load, and the control system adjusts the outlet voltage frequency of the permanent magnet synchronous generator G to be constant at 50 Hz.

[0069] 212) The voltage measurement module measures the voltage amplitude difference at both ends of the grid-connected circuit breaker K1, and the control system puts the parallel adjustable reactor L into operation, and adjusts the parallel adjustable reactor L to make the voltage amplitudes at both ends of the grid-connected circuit breaker K1 equal.

[0070] 213) The phase measurement module measures the voltage phase difference across the grid-connected circuit breaker K1, and the control system controls the output voltage phase of the permanent magnet synchronous generator G so that the voltage phase difference across the grid-connected circuit breaker K1 is 0.

[0071] 214) When the voltage (or frequency deviation) of the microgrid reaches the high starting value of the compressed air energy storage device |ΔV high |(or |Δf high |) and continues for the preset delay t2, the control system sends a remote control signal to close the grid-connected circuit breaker K1 and disconnect the interconnecting circuit breaker K2 at the same time.

[0072] 215) The control system adjusts the speed of the pneumatic engine M to keep the voltage frequency of the microgrid constant at a preset frequency of 50 Hz. At the same time, the control system cuts off the parallel adjustable reactor L and puts in the parallel capacitor C. By adjusting the parallel capacitor C, the voltage amplitude of the microgrid is kept constant at a preset value V0.

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

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

[0075] 222) The control system sends a remote control signal to monitor the voltage phase between the microgrid and the external grid, so that the interconnecting circuit breaker K2 performs 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 reaches 0. During the adjustment process, the control system adjusts the parallel capacitor C to make the output inductive reactive power of the permanent magnet synchronous generator G as small as possible.

[0077] 224) The control system adjusts the parallel capacitor C or the parallel 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 disconnect the grid-connected circuit breaker K1.

[0079] 226) The control system closes the air engine valve, and the rotor speed of the permanent magnet synchronous generator G gradually decreases to 0 under the action of damping.

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

[0081] 31) The specific process from off-grid to grid-connected is:

[0082] 311) When the microgrid is detected to lose pressure and the delay is t3, the control system sends a remote control signal to disconnect the interconnecting circuit breaker K2, and then disconnect the outgoing circuit breakers K3-Kn, cutting off all 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 at no load, and the control system adjusts the pneumatic engine M so that the outlet voltage frequency of the permanent magnet synchronous generator G is constant at 50 Hz.

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

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

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

[0087] 321) When the external grid voltage is detected to be restored, the control system adjusts the parallel 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 interconnecting circuit breaker K2, so that the interconnecting circuit breaker K2 executes 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 reaches 0. During the adjustment process, the control system adjusts the parallel 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 parallel capacitor C or the parallel adjustable reactor L to make the output inductive reactive power of the permanent magnet synchronous generator G zero.

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

[0092] 327) Close the air engine valve, and the rotor speed of the permanent magnet synchronous generator G gradually decreases to 0 under the action of damping.

[0093] The present invention has the following characteristics:

[0094] The present invention adjusts the port voltage of the permanent magnet synchronous generator G when it is unloaded, thereby minimizing the reactive impact current when connected to the grid. The present invention sets two high and low starting constants for the distributed compressed air energy storage device according to the voltage and frequency deviation of the microgrid, which greatly reduces the risk of power outages in the microgrid due to external grid disturbances. The grid connection mode of the present invention when the microgrid performs a black start avoids too slow acceleration of the generator speed when starting with load.

[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, the steps of the on-grid and off-grid control method of the distributed compressed air energy storage device are implemented, for example, including: under the normal operation of the microgrid, the compressed air energy storage device is controlled to switch between on-grid and off-grid at a fixed time; when the voltage / frequency of the microgrid reaches the warning threshold, the compressed air energy storage device is automatically controlled to switch between on-grid and off-grid; when the microgrid uses the energy storage device for black start, the compressed air energy storage device is automatically controlled to switch between on-grid and off-grid according to a predetermined program. Wherein, the memory may include a memory, such as a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk memory, etc.; the processor, the network interface, and the memory are interconnected through an internal bus, and the internal bus may be an industrial standard architecture bus, a peripheral component interconnection standard bus, an extended industrial standard architecture bus, etc., and the bus may 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 a program code, and the program code includes computer operation instructions. The memory may include a memory and a 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, the steps of the on-grid and off-grid control method of the distributed compressed air energy storage device are implemented, for example, including: under the normal operation of the microgrid, the compressed air energy storage device is controlled to switch between on-grid and off-grid at a fixed time; when the voltage / frequency of the microgrid reaches the warning threshold, the compressed air energy storage device is automatically controlled to switch between on-grid and off-grid; when the microgrid uses the energy storage device for black start, the compressed air energy storage device is automatically controlled 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 (cache), etc. The non-volatile memory may include a read-only memory (ROM), a hard disk, a flash memory, an optical disk, a magnetic disk, etc.

[0099] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

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

[0101] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0102] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection 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 according to a predetermined program to switch between grid connection and off-grid operation.

2. The on-grid and off-grid control method of a distributed compressed air energy storage device according to claim 1, characterized in that: 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 parallel capacitor (C) is connected to the low-voltage side bus (B1) of the microgrid, 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).

3. 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 process of switching 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 without 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; The voltage amplitude difference ΔV at both ends of the grid-connected circuit breaker (K1) is measured, and a parallel adjustable reactor (L) is put into operation, and the reactance value of the parallel adjustable reactor (L) is adjusted to make the voltage amplitudes at both ends of the grid-connected circuit breaker (K1) equal; 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).

4. 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.

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 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.

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 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.

7. 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.

8. 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.

9. 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 1-8 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the computer program implements the following claims 1 to 8 Any of the steps of the on-grid and off-grid control method for a distributed compressed air energy storage device.

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