A safety control device and safety control method for an energy storage flywheel array system

Abstract

The present invention belongs to the technical field of energy storage flywheels, and provides a safety control device and a safety control method for an energy storage flywheel array system. The device includes a controller and an energy storage flywheel array system, the energy storage flywheel array system includes a switch cabinet and a plurality of parallel energy storage array modules connected thereto; the energy storage array module includes a grid-side converter and a plurality of parallel energy storage flywheel systems connected thereto, the energy storage flywheel system includes a machine-side converter, an energy storage flywheel body and a braking resistor, and the braking resistor is arranged between the machine-side converter and the energy storage flywheel body; the controller is used to determine the fault type of the energy storage flywheel array system, and when it is determined to be an electrical system fault, the action of the switch cabinet is determined in turn and the braking resistor is turned on according to the faulty components in the electrical system; when it is determined to be an energy storage flywheel body fault, the switch of the switch cabinet is closed, the braking resistor is turned on, and the charging and discharging work of the faulty energy storage flywheel body is determined according to the energy stored in the flywheel energy storage system at the time of the fault.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage flywheels, and in particular relates to a safety control device and a safety control method for an energy storage flywheel array system. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] The flywheel energy storage system is an energy storage device for electromechanical energy conversion, which breaks through the limitations of chemical batteries and realizes energy storage by physical methods. Through the electric / generating reciprocal bidirectional motor, the mutual conversion and storage between electric energy and the mechanical kinetic energy of the high-speed running flywheel, and through frequency modulation, rectification, constant voltage and different types of load interfaces. When storing energy, the electric energy is converted by the power converter to drive the motor to run, and the motor drives the flywheel to accelerate. The flywheel stores the energy in the form of kinetic energy, completing the energy storage process of converting electric energy to mechanical energy. The energy is stored in the high-speed rotating flywheel body; after that, the motor maintains a constant speed until it receives a control signal for energy release; when releasing energy, the high-speed rotating flywheel drives the motor to generate electricity, and the power converter outputs the current and voltage suitable for the load, completing the energy release process of converting mechanical energy to electric energy. The entire flywheel energy storage system realizes the input, storage and output process of electric energy.

[0004] At present, the safety control method of single energy storage flywheel is generally used, such as Figure 1 As shown, braking is performed directly through a braking resistor, which is generally connected to the DC side or the flywheel side. When the braking resistor is connected to the DC side and the grid-side converter fails, the energy storage flywheel will not be able to brake; when the braking resistor is connected to the flywheel side and the machine-side converter is directly connected to the energy storage flywheel, if the machine-side converter fails, the braking will be uncontrollable. Moreover, the existing safety control strategy for a single energy storage flywheel is simple and cannot be applied to the entire energy storage flywheel array system, thus failing to ensure the stable operation of the entire energy storage flywheel array system. Summary of the invention

[0005] In order to solve the technical problems existing in the above-mentioned background technology, the present invention provides an energy storage flywheel array system, a braking control method and a power grid system, which are suitable for the safety control of the entire energy storage flywheel array system and can ensure the stable operation of the entire energy storage flywheel array system.

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

[0007] A first aspect of the present invention provides a safety control device for an energy storage flywheel array system, which includes a controller and an energy storage flywheel array system, wherein the energy storage flywheel array system includes a switch cabinet and a plurality of parallel energy storage array modules connected thereto; the energy storage array module includes a grid-side converter and a plurality of parallel energy storage flywheel systems connected thereto, wherein the energy storage flywheel system includes a machine-side converter, an energy storage flywheel body and a braking resistor, wherein the braking resistor is arranged between the machine-side converter and the energy storage flywheel body;

[0008] The controller is used to determine the fault type of the energy storage flywheel array system. When it is determined that the electrical system is faulty, the action of the switch cabinet is determined and the braking resistor is turned on in sequence according to the faulty components in the electrical system; when it is determined that the energy storage flywheel body is faulty, the switch of the switch cabinet is closed, the braking resistor is turned on, and the charging and discharging operation of the faulty energy storage flywheel body is determined according to the energy stored in the flywheel energy storage system at the time of the fault.

[0009] As an implementation mode, the controller is used to: when it is determined that a switch cabinet in the electrical system is faulty, execute a switch cabinet protection action.

[0010] As an implementation mode, the controller is used to: when it is determined that a grid-side converter or a generator-side converter in the electrical system fails, execute a switch cabinet closing action.

[0011] As an implementation mode, the controller is used to: when it is determined that the flywheel speed is lower than or equal to the minimum speed that can discharge at full power, control the faulty flywheel to continue braking by its own braking resistor until it stops, and then stop the operation of other energy storage flywheels, shut down the energy storage flywheel array system, and perform fault detection and maintenance.

[0012] As an implementation mode, the controller is used for: when the flywheel speed is higher than the minimum speed for full power discharge, and the energy stored in the faulty energy storage flywheel is less than the sum of the energy that can be absorbed by other energy storage flywheels, controlling the faulty flywheel to continue braking by its own braking resistor while discharging to other energy storage flywheels until it stops, and then stopping the operation of other energy storage flywheels, shutting down the energy storage flywheel array system, and performing troubleshooting and maintenance.

[0013] As an implementation mode, the controller is used for: when the energy stored by the faulty energy storage flywheel is less than the sum of the energies that can be absorbed by other energy storage flywheels, controlling the faulty flywheel to continue braking by its own braking resistor while disconnecting other energy storage flywheel bodies from corresponding machine-side converters, controlling other side converters to supply power to corresponding braking resistors, so that the faulty flywheel shares the braking resistors of other energy storage flywheels at the same time until it stops, and then stopping the operation of other energy storage flywheels, shutting down the energy storage flywheel array system, and performing troubleshooting and maintenance.

[0014] As an implementation mode, the controller is connected to a first relay, and the first relay is connected in series between the generator-side converter and the energy storage flywheel body;

[0015] As an implementation manner, the controller is connected to a second relay, and the second relay is used to control the turning on and off of the braking resistor.

[0016] As an implementation manner, the controller is connected to a third relay, and the third relay is connected in series between the generator-side converter and the grid-side converter.

[0017] As an implementation mode, the controller is connected to a fourth relay, and the fourth relay is connected in series between the grid-side converter and the switch cabinet.

[0018] A second aspect of the present invention provides a control method for a safety control device of an energy storage flywheel array system as described above, comprising:

[0019] Determine the fault type of the energy storage flywheel array system. When it is determined to be an electrical system fault, determine the action of the switch cabinet and turn on the braking resistor in sequence according to the faulty components in the electrical system; when it is determined to be a fault of the energy storage flywheel body, close the switch of the switch cabinet, turn on the braking resistor, and then determine the charging and discharging work of the faulty energy storage flywheel body according to the energy stored in the flywheel energy storage system at the time of the fault.

[0020] As an implementation method, when it is determined that a switch cabinet in the electrical system is faulty, a switch cabinet protection action is executed;

[0021] When it is determined that the grid-side converter or the machine-side converter in the electrical system fails, the switch cabinet is closed.

[0022] As an implementation method, when it is determined that the flywheel speed is lower than or equal to the minimum speed that can discharge at full power, the faulty flywheel is controlled to continue braking by its own braking resistor until it stops, and then the operation of other energy storage flywheels is stopped, the energy storage flywheel array system is shut down, and fault troubleshooting and maintenance are carried out.

[0023] As an implementation method, when the flywheel speed is higher than the minimum speed for full power discharge, and the energy stored in the faulty energy storage flywheel is less than the sum of the energies that can be absorbed by other energy storage flywheels, the faulty flywheel is controlled to continue braking by its own braking resistor while discharging to other energy storage flywheels until it stops, and then the operation of other energy storage flywheels is stopped, the energy storage flywheel array system is shut down, and fault troubleshooting and maintenance are carried out.

[0024] As an implementation method, when the energy stored in the faulty energy storage flywheel is less than the sum of the energies that can be absorbed by other energy storage flywheels, the faulty flywheel is controlled to continue braking by its own braking resistor while disconnecting other energy storage flywheel bodies from corresponding machine-side converters, and controlling other side converters to supply power to corresponding braking resistors, so that the faulty flywheel can share the braking resistors of other energy storage flywheels at the same time until it stops, and then stop the operation of other energy storage flywheels, shut down the energy storage flywheel array system, and perform troubleshooting and maintenance.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention provides a safety control device and control method for an energy storage flywheel array system. The device and control method first determine the fault type of the energy storage flywheel array system. When it is determined that an electrical system fault occurs, the action of the switch cabinet and the start of the braking resistor are determined in sequence according to the faulty components in the electrical system. When it is determined that an energy storage flywheel body fails, the switch of the switch cabinet is closed, the braking resistor is turned on, and the charging and discharging operation of the faulty energy storage flywheel body is determined according to the energy stored in the flywheel energy storage system at the time of the failure. The device and control method are applicable to the entire energy storage flywheel array system, and the stable operation of the entire energy storage flywheel array system is improved. Moreover, a braking resistor is connected between each energy storage flywheel body and the corresponding machine-side converter, which can greatly improve the braking efficiency, safety and redundancy.

[0027] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings in the specification, which constitute 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 improper limitations on the present invention.

[0029] Figure 1 It is a schematic diagram of the structure of a traditional energy storage flywheel array system;

[0030] Figure 2 is a schematic diagram of the structure of an energy storage flywheel array system according to an embodiment of the present invention;

[0031] Figure 3 It is a flow chart of a safety control method for an energy storage flywheel array system according to an embodiment of the present invention.

[0032] Among them, 1. energy storage flywheel body; 2. braking resistor; 3. machine-side converter; 4. grid-side converter; 5. switch cabinet; 11. first relay; 12. second relay; 13. third relay; 14. fourth relay; 101. energy storage flywheel system; 102. energy storage array module; 103. energy storage flywheel array system. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0034] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0035] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0036] A single energy storage flywheel is generally connected to the inverter by the energy storage flywheel body, and then connected to the grid-side converter (PCS), and connected to the AC power grid through the switch cabinet. Its working principle: when absorbing electric energy through the power grid, the PCS converts the AC power of the power grid into DC power, and then drives the energy storage flywheel body through the inverter, so that the speed of the energy storage flywheel body increases, and the electric energy is converted into the kinetic energy of the rotor and stored; when feeding energy back to the AC power grid, the speed of the energy storage flywheel body decreases, and the kinetic energy is converted into electric energy through the machine-side inverter, and then the DC power is converted into industrial frequency AC power and fed back to the power grid by the PCS. In general, the braking resistor is such as Figure 1 The connection shown is on the DC side or flywheel and controlled by the corresponding relay.

[0037] Embodiment 1

[0038] like Figure 2 As shown, this embodiment provides a safety control device for an energy storage flywheel array system, which includes a controller and an energy storage flywheel array system 103, wherein the energy storage flywheel array system 103 includes a switch cabinet 5 and a plurality of parallel energy storage array modules 102 connected thereto; the energy storage array module 102 includes a grid-side converter 4 and a plurality of parallel energy storage flywheel systems 101 connected thereto, wherein the energy storage flywheel system 101 includes a machine-side converter 3, an energy storage flywheel body 1 and a braking resistor 2, wherein the braking resistor 2 is arranged between the machine-side converter 3 and the energy storage flywheel body 1;

[0039] The machine-side converter 3 is a frequency converter in this embodiment; the grid-side converter 4 is represented by PCS in this embodiment.

[0040] In this embodiment, the controller is connected to the first relay 11, which is connected in series between the machine-side converter 3 and the energy storage flywheel body 1; the controller is connected to the second relay 12, which is used to control the opening and closing of the braking resistor 2.

[0041] The controller is connected to a third relay 13, which is connected in series between the generator-side converter 3 and the grid-side converter 4. The controller is connected to a fourth relay 14, which is connected in series between the grid-side converter 4 and the switch cabinet 5.

[0042] The controller is used to determine the fault type of the energy storage flywheel array system. When it is determined that the electrical system is faulty, the action of the switch cabinet is determined and the braking resistor is turned on in sequence according to the faulty components in the electrical system; when it is determined that the energy storage flywheel body is faulty, the switch of the switch cabinet is closed, the braking resistor is turned on, and the charging and discharging operation of the faulty energy storage flywheel body is determined according to the energy stored in the flywheel energy storage system at the time of the fault.

[0043] The switch cabinet is opened and closed by the controller controlling the on and off of the fourth relay;

[0044] The opening and closing of the braking resistor is realized by the controller controlling the first relay and the second relay;

[0045] The on-off of the machine-side converter is achieved by the controller controlling the on-off of the third relay.

[0046] In this embodiment, the electrical system faults include three types, namely, switch cabinet fault, grid-side converter fault (ie, PCS fault) and machine-side converter fault (ie, inverter fault).

[0047] In the specific implementation process, the controller is used to: when it is determined that the switch cabinet in the electrical system is faulty, execute the switch cabinet protection action; when it is determined that the grid-side converter or the machine-side converter in the electrical system is faulty, execute the switch cabinet shutdown action.

[0048] In the specific implementation process, the controller is used to: when it is determined that the flywheel speed is lower than or equal to the minimum speed that can discharge at full power (that is, when the system energy storage capacity is low), control the faulty flywheel to continue braking by its own braking resistor until it stops, and then stop the operation of other energy storage flywheels, shut down the energy storage flywheel array system, and perform fault detection and maintenance.

[0049] When the flywheel speed is higher than the minimum speed for full power discharge, and the energy stored in the faulty energy storage flywheel is less than the sum of the energy that can be absorbed by other energy storage flywheels (that is, when the system is storing energy), the faulty flywheel is controlled to continue braking by its own braking resistor while discharging to other energy storage flywheels until it stops, and then the operation of other energy storage flywheels is stopped, the energy storage flywheel array system is shut down, and fault detection and maintenance are carried out.

[0050] When the energy stored in the faulty energy storage flywheel is less than the sum of the energy that can be absorbed by other energy storage flywheels (i.e., when the system energy storage is high), the faulty flywheel is controlled to continue braking by its own braking resistor while disconnecting other energy storage flywheel bodies from the corresponding machine-side converters, and controlling other side converters to supply power to the corresponding braking resistors, so that the faulty flywheel can share the braking resistors of other energy storage flywheels at the same time until it stops, and then stop the operation of other energy storage flywheels, shut down the energy storage flywheel array system, and perform troubleshooting and maintenance.

[0051] Embodiment 2

[0052] Reference Figure 3 This embodiment provides a control method for a safety control device of an energy storage flywheel array system as described above, which includes:

[0053] Determine the fault type of the energy storage flywheel array system. When it is determined to be an electrical system fault, determine the action of the switch cabinet and turn on the braking resistor in sequence according to the faulty components in the electrical system; when it is determined to be a fault of the energy storage flywheel body, close the switch of the switch cabinet, turn on the braking resistor, and then determine the charging and discharging work of the faulty energy storage flywheel body according to the energy stored in the flywheel energy storage system at the time of the fault.

[0054] In this embodiment, the electrical system faults include three types, namely switch cabinet fault, grid-side converter fault and generator-side converter fault.

[0055] When it is determined that the switch cabinet in the electrical system is faulty, the switch cabinet protection action is executed.

[0056] Specifically, the switch cabinet fault handling method is as follows:

[0057] First, the switch cabinet is disconnected; then, all the third and fourth relays are disconnected, and all the first and second relays are closed; the brake resistor starts to work and brakes until all flywheels stop running. Finally, the energy storage flywheel array system is shut down and fault detection and maintenance are carried out.

[0058] When it is determined that the grid-side converter or the machine-side converter in the electrical system fails, the switch cabinet is closed.

[0059] Specifically, the fault handling methods of the grid-side converter and the generator-side converter are as follows:

[0060] First, turn off the switch cabinet switch; then, disconnect all the third and fourth relays, and close all the first and second relays; the brake resistor starts to work and brake until all flywheels stop running. Finally, turn off the energy storage flywheel array system and perform fault detection and maintenance.

[0061] Energy storage flywheel body fault handling method:

[0062] First, turn off the switch cabinet switch, close the first relay and the second relay of the faulty flywheel; the brake resistor starts to work. Then make a judgment based on the energy stored in the flywheel energy storage system at the time of the fault.

[0063] When it is determined that the flywheel speed is lower than or equal to the minimum speed for full power discharge (that is, when the system energy storage is low), the faulty flywheel is controlled to continue braking by its own braking resistor until it stops, and then the operation of other energy storage flywheels is stopped, the energy storage flywheel array system is shut down, and fault troubleshooting and maintenance are carried out.

[0064] When the flywheel speed is higher than the minimum speed for full power discharge, and the energy stored in the faulty energy storage flywheel is less than the sum of the energy that can be absorbed by other energy storage flywheels (that is, when the system is storing energy), the faulty flywheel is controlled to continue braking by its own braking resistor while discharging to other energy storage flywheels until it stops, and then the operation of other energy storage flywheels is stopped, the energy storage flywheel array system is shut down, and fault detection and maintenance are carried out.

[0065] When the energy stored in the faulty energy storage flywheel is less than the sum of the energy that can be absorbed by other energy storage flywheels (i.e., when the system energy storage is high), the faulty flywheel is controlled to continue braking by its own braking resistor while disconnecting the first relay of other flywheels and closing the second relay, thereby achieving the purpose of disconnecting the other energy storage flywheel bodies from the corresponding machine-side converters, and controlling the other side converters to supply power to the corresponding braking resistors, so that the faulty flywheel simultaneously shares the braking resistors of other energy storage flywheels until it stops, and then stops the operation of other energy storage flywheels, shuts down the energy storage flywheel array system, and performs fault troubleshooting and maintenance.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A safety control device for an energy storage flywheel array system, characterized in that: It includes a controller and an energy storage flywheel array system, wherein the energy storage flywheel array system includes a switch cabinet and a plurality of parallel energy storage array modules connected thereto; the energy storage array module includes a grid-side converter and a plurality of parallel energy storage flywheel systems connected thereto, wherein the energy storage flywheel system includes a machine-side converter, an energy storage flywheel body and a braking resistor, wherein the braking resistor is arranged between the machine-side converter and the energy storage flywheel body; The controller is used to determine the fault type of the energy storage flywheel array system. When it is determined that the electrical system is faulty, the controller determines the action of the switch cabinet and turns on the brake resistor in sequence according to the faulty components in the electrical system; when it is determined that the energy storage flywheel body is faulty, the switch of the switch cabinet is closed, the brake resistor is turned on, and the charging and discharging operation of the faulty energy storage flywheel body is determined according to the energy stored in the flywheel energy storage system at the time of the fault; The controller is used to: when the flywheel speed is higher than the minimum speed for full power discharge, and the energy stored in the faulty energy storage flywheel is less than the sum of the energy that can be absorbed by other energy storage flywheels, control the faulty flywheel to continue braking by its own braking resistor while discharging to other energy storage flywheels until it stops, and then stop the operation of other energy storage flywheels, shut down the energy storage flywheel array system, and perform fault detection and maintenance; When the flywheel speed is higher than the minimum speed for full power discharge, and the energy stored in the faulty energy storage flywheel is less than the sum of the energy that can be absorbed by other energy storage flywheels, the faulty flywheel is controlled to continue braking by its own braking resistor while discharging to other energy storage flywheels until it stops, and then the other energy storage flywheels are stopped, the energy storage flywheel array system is shut down, and fault detection and maintenance are carried out; When the energy stored in the faulty energy storage flywheel is greater than the sum of the energies that can be absorbed by other energy storage flywheels, the faulty flywheel is controlled to continue braking by its own braking resistor while disconnecting other energy storage flywheel bodies from the corresponding machine-side converters, and controlling other side converters to supply power to the corresponding braking resistors, so that the faulty flywheel can share the braking resistors of other energy storage flywheels at the same time until it stops, and then stop the operation of other energy storage flywheels, shut down the energy storage flywheel array system, and perform troubleshooting and maintenance.

2. The safety control device for the energy storage flywheel array system according to claim 1, characterized in that: The controller is used to: when it is determined that the switch cabinet in the electrical system is faulty, execute the switch cabinet protection action; Or the controller is used to: when it is determined that the grid-side converter or the machine-side converter in the electrical system fails, execute the switch cabinet closing action.

3. The safety control device for the energy storage flywheel array system according to claim 1, characterized in that: The controller is connected to a first relay, and the first relay is connected in series between the machine-side converter and the energy storage flywheel body; Or the controller is connected to a second relay, and the second relay is used to control the opening and closing of the braking resistor; or the controller is connected to a third relay, and the third relay is connected in series between the generator-side converter and the grid-side converter; Or the controller is connected to a fourth relay, and the fourth relay is connected in series between the grid-side converter and the switch cabinet.

4. A control method for a safety control device of an energy storage flywheel array system according to any one of claims 1 to 3, characterized in that: include: Determine the fault type of the energy storage flywheel array system. When it is determined to be an electrical system fault, determine the action of the switch cabinet and turn on the braking resistor in sequence according to the faulty components in the electrical system; when it is determined to be a fault of the energy storage flywheel body, close the switch of the switch cabinet, turn on the braking resistor, and then determine the charging and discharging work of the faulty energy storage flywheel body according to the energy stored in the flywheel energy storage system at the time of the fault.

5. The control method of the safety control device of the energy storage flywheel array system according to claim 4, characterized in that: When it is determined that the switch cabinet in the electrical system is faulty, the switch cabinet protection action is executed; When it is determined that the grid-side converter or the machine-side converter in the electrical system fails, the switch cabinet is closed.

6. The control method of the safety control device of the energy storage flywheel array system according to claim 4, characterized in that: When it is determined that the flywheel speed is lower than or equal to the minimum speed for full power discharge, the faulty flywheel is controlled to continue braking by its own braking resistor until it stops, and then the operation of other energy storage flywheels is stopped, the energy storage flywheel array system is shut down, and fault troubleshooting and maintenance are carried out.

7. The control method of the safety control device of the energy storage flywheel array system according to claim 4, characterized in that: When the flywheel speed is higher than the minimum speed for full power discharge, and the energy stored in the faulty energy storage flywheel is less than the sum of the energy that can be absorbed by other energy storage flywheels, the faulty flywheel is controlled to continue braking by its own braking resistor while discharging to other energy storage flywheels until it stops, and then the other energy storage flywheels are stopped, the energy storage flywheel array system is shut down, and fault detection and maintenance are carried out; or When the energy stored in the faulty energy storage flywheel is greater than the sum of the energies that can be absorbed by other energy storage flywheels, the faulty flywheel is controlled to continue braking by its own braking resistor while disconnecting other energy storage flywheel bodies from the corresponding machine-side converters, and controlling other side converters to supply power to the corresponding braking resistors, so that the faulty flywheel can share the braking resistors of other energy storage flywheels at the same time until it stops, and then stop the operation of other energy storage flywheels, shut down the energy storage flywheel array system, and perform troubleshooting and maintenance.

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