Energy storage flywheel energy release device and method

Abstract

The present disclosure provides an energy storage flywheel energy release device and method, which comprises a control unit, a converter unit, a flywheel energy storage unit, an energy consumption loop unit and a direct current braking unit. The control unit is connected with the converter unit, the flywheel energy storage unit, the energy consumption loop unit and the direct current braking unit respectively. The control unit is used to control the converter unit and the flywheel energy storage unit to supply power to the power grid when the flywheel fails, and to obtain the motor speed and the flywheel rotor speed. Based on the motor speed or the flywheel rotor speed, the energy consumption start instruction or the braking start instruction is generated. The energy consumption loop unit is used to discharge when receiving the energy consumption start instruction. The direct current braking unit is used to brake the flywheel rotor when receiving the braking start instruction. According to the device of the present disclosure, the kinetic energy of the flywheel can be released and transferred in time to avoid personal injury and equipment damage.

Description

Technical Field

[0001] This disclosure relates to the field of flywheel energy storage technology, and in particular to an energy storage flywheel energy release device and method. Background Technology

[0002] Flywheel energy storage stores energy or momentum in a high-speed rotating flywheel rotor, using a motor to convert electrical energy into mechanical kinetic energy and back into electrical energy. In a flywheel energy storage system, a single flywheel unit mainly comprises a rotor system, a bearing system, a motor, and other vacuum, cooling, and control auxiliary systems. The flywheel itself is the core component of the system, its function being to increase the rotor's limiting angular velocity and maximize the energy storage capacity of the flywheel energy storage system.

[0003] Flywheel energy storage is an advanced physical energy storage technology with features such as high safety, high power density, fast response speed, long life, maintenance-free operation, good scalability, no pollution, small footprint for underground installation, and no need for special fire protection or ventilation systems.

[0004] Existing flywheel energy storage systems mainly consist of a transformer, a generator-side PCS (converter), a grid-side PCS, a control cabinet, a motor, a flywheel rotor, and a braking resistor. The braking system of the flywheel energy storage system comprises the grid-side PCS and the braking resistor. When an instability fault occurs during high-speed flywheel rotation, the existing braking system cannot release and transfer the flywheel's kinetic energy, which can easily lead to personal injury and equipment damage. Summary of the Invention

[0005] This disclosure aims to at least partially address one of the technical problems in the related art.

[0006] Therefore, this disclosure provides an energy storage flywheel energy release device and method, the main purpose of which is to release and transfer the kinetic energy of the flywheel in a timely manner to avoid personal injury and equipment damage.

[0007] According to a first aspect of the present disclosure, an energy storage flywheel energy release device is provided, including a control unit, a converter unit, a flywheel energy storage unit, an energy dissipation circuit unit, and a DC braking unit, wherein the control unit is connected to the converter unit, the flywheel energy storage unit, the energy dissipation circuit unit, and the DC braking unit respectively;

[0008] The control unit is used to generate machine-side rectification control commands and grid-side inverter control commands when the flywheel experiences instability, and to acquire the motor speed and flywheel rotor speed, and to generate energy-consuming start commands or braking start commands based on the motor speed or flywheel rotor speed.

[0009] The converter unit includes a DC bus, a grid-side converter, a generator-side converter, and a transformer. The DC side of the grid-side converter and the DC side of the generator-side converter are connected to the DC bus. The AC side of the grid-side converter is connected to the power grid through the transformer. The AC side of the generator-side converter is connected to the flywheel energy storage unit. The generator-side converter supplies power to the DC bus based on the generator-side rectification control command, and the grid-side converter supplies power to the power grid based on the grid-side inverter control command.

[0010] The flywheel energy storage unit includes a motor and a flywheel rotor. The flywheel rotor is used to drive the motor to generate electricity when the machine-side converter receives the machine-side rectification control command.

[0011] The energy-consuming circuit unit is connected to the DC bus, and the energy-consuming circuit unit is used to discharge when the energy-consuming start command is received;

[0012] The DC braking unit is connected to the DC bus and is used to brake the flywheel rotor when the braking start command is received.

[0013] In one embodiment of this disclosure, the energy-consuming circuit unit includes a thyristor and a discharge resistor, and the positive terminal of the DC bus is connected to the negative terminal of the DC bus via the thyristor and the discharge resistor.

[0014] In one embodiment of this disclosure, the discharge resistor is a zinc oxide nonlinear resistor.

[0015] In one embodiment of this disclosure, the DC braking unit includes a transistor, an external resistor, and a braking winding, wherein the positive terminal of the DC bus is connected to the negative terminal of the DC bus via the transistor, the external resistor, and the braking winding.

[0016] In one embodiment of this disclosure, the transistor is an insulated-gate bipolar transistor.

[0017] In one embodiment of this disclosure, the braking winding is a coil winding disposed in the flywheel rotor housing.

[0018] In one embodiment of this disclosure, the DC braking unit further includes a boost circuit disposed between the transistor and the external resistor.

[0019] In one embodiment of this disclosure, the energy storage flywheel energy release device further includes a temperature monitoring unit connected to the control unit. The temperature monitoring unit is used to monitor the temperature inside the flywheel rotor housing and send the data to the control unit. The control unit is also used to determine the temperature and a temperature threshold, and to control the transistor to turn off when the temperature reaches the temperature threshold.

[0020] According to a second aspect of this disclosure, a method for releasing energy from an energy storage flywheel using the energy release device described in the first aspect is provided, comprising:

[0021] When the flywheel experiences instability, the control unit generates machine-side rectification control commands and grid-side inverter control commands.

[0022] The generator-side converter supplies power to the DC bus based on the generator-side rectification control command, and the grid-side converter supplies power to the grid based on the grid-side inverter control command. The flywheel rotor drives the motor to generate electricity when the generator-side converter receives the generator-side rectification control command.

[0023] The control unit also acquires the motor speed and flywheel rotor speed, and generates an energy-consuming start command or a braking start command based on the motor speed or flywheel rotor speed;

[0024] The energy dissipation circuit unit discharges when it receives the energy dissipation start command, and the DC braking unit brakes the flywheel rotor when it receives the braking start command.

[0025] In one embodiment of this disclosure, the control unit further includes: acquiring the temperature inside the flywheel rotor housing, determining the temperature against a temperature threshold, and controlling the transistor in the DC braking unit to turn off when the temperature reaches the temperature threshold.

[0026] In one or more embodiments of this disclosure, a control unit, a converter unit, a flywheel energy storage unit, an energy dissipation circuit unit, and a DC braking unit are included. The control unit is connected to the converter unit, the flywheel energy storage unit, the energy dissipation circuit unit, and the DC braking unit, respectively. The control unit is used to generate machine-side rectification control commands and grid-side inverter control commands when a flywheel instability fault occurs, and to acquire the motor speed and flywheel rotor speed. Based on the motor speed or flywheel rotor speed, it generates an energy dissipation start command or a braking start command. The converter unit includes a DC bus, a grid-side converter, a machine-side converter, and a transformer. The DC side of the grid-side converter and the DC side of the machine-side converter are connected to the DC bus. The grid-side converter is connected to the grid via a transformer on its AC side, while the generator-side converter is connected to the flywheel energy storage unit on its AC side. The generator-side converter supplies power to the DC bus based on generator-side rectification control commands, and the grid-side converter supplies power to the grid based on grid-side inverter control commands. The flywheel energy storage unit includes a motor and a flywheel rotor. The flywheel rotor drives the motor to generate electricity when the generator-side converter receives a generator-side rectification control command. The energy dissipation circuit unit is connected to the DC bus and discharges when it receives an energy dissipation start command. The DC braking unit is connected to the DC bus and brakes the flywheel rotor when it receives a braking start command. In this configuration, when the flywheel experiences instability, the converter unit transfers electrical energy to the grid, the energy dissipation circuit unit consumes some of the electrical energy in the flywheel energy storage unit, and the DC braking unit assists in braking the flywheel rotor. Compared to existing technologies that rely solely on a braking system to brake the flywheel during a fault, this device can promptly release and transfer the flywheel's kinetic energy to prevent personal injury and equipment damage.

[0027] Additional aspects and advantages of this disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this disclosure. Attached Figure Description

[0028] The above and / or additional aspects and advantages of this disclosure will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, in which:

[0029] Figure 1 This diagram shows a block diagram of an energy storage flywheel energy release device provided in an embodiment of the present disclosure;

[0030] Figure 2 This diagram illustrates the connection of an energy storage flywheel energy release device according to an embodiment of the present disclosure.

[0031] Figure 3 A flowchart illustrating an energy release method for an energy storage flywheel provided in an embodiment of this disclosure is shown. Detailed Implementation

[0032] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this disclosure as detailed in the appended claims.

[0033] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly and specifically defined. It should also be understood that the term "and / or" as used in this disclosure refers to and includes any or all possible combinations of one or more associated listed items.

[0035] Embodiments of this disclosure are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this disclosure, and should not be construed as limiting this disclosure.

[0036] This disclosure provides an energy storage flywheel energy release device and method, the main purpose of which is to release and transfer the kinetic energy of the flywheel in a timely manner to avoid personal injury and equipment damage.

[0037] In the first embodiment, Figure 1 This diagram illustrates a block diagram of an energy storage flywheel energy release device provided in an embodiment of the present disclosure. Figure 2 This diagram illustrates the connection of an energy storage flywheel energy release device according to an embodiment of this disclosure. In this disclosure, the energy storage flywheel energy release device may be simply referred to as a release device. Figure 1 As shown, the energy storage flywheel energy release device 10 includes a control unit 11, a converter unit 12, a flywheel energy storage unit 13, an energy dissipation circuit unit 14, and a DC braking unit 15.

[0038] In embodiments of this disclosure, the control unit 11 is connected to the inverter unit 12, the flywheel energy storage unit 13, the energy dissipation circuit unit 14, and the DC braking unit 15, respectively. The inverter unit 12 is connected to the flywheel energy storage unit 13, the energy dissipation circuit unit 14, and the DC braking unit 15, respectively.

[0039] In this embodiment, the control unit 11 is used to generate machine-side rectification control commands and grid-side inverter control commands when the flywheel experiences instability, and to obtain the motor speed and flywheel rotor speed, and generate energy-consuming start commands or braking start commands based on the motor speed or flywheel rotor speed.

[0040] In this embodiment, the control unit 11 may be a controller (see...) Figure 2 ).

[0041] In this embodiment, the control unit 11 is used to generate a machine-side rectification control command and send it to the machine-side converter in the converter unit 12 when the flywheel experiences an instability fault. It is also used to generate a grid-side inverter control command and send it to the grid-side converter in the converter unit 12 when the flywheel experiences an instability fault. At this time, the kinetic energy in the flywheel energy storage unit 13 is converted into electrical energy and sent to the power grid via the converter unit 12.

[0042] In this embodiment, the control unit 11 is used to acquire the motor speed and the flywheel rotor speed, and generate an energy-consuming start command or a braking start command based on the motor speed or the flywheel rotor speed.

[0043] Specifically, when the motor speed is greater than a preset speed, such as 3000 rpm, an energy-consuming start command is generated and sent to the energy-consuming circuit unit 14. When both the motor speed and the flywheel rotor speed are lower than 3000 rpm, an energy-consuming start command is generated and sent to the energy-consuming circuit unit 14, and a braking start command is generated and sent to the DC braking unit 15.

[0044] In this embodiment, the control unit 11 is also used to generate a machine-side inverter control command and send it to the machine-side converter in the converter unit 12 when the flywheel is normal and fault-free and during the energy storage stage. It is also used to generate a grid-side rectification control command and send it to the grid-side converter in the converter unit 12 when the flywheel is normal and fault-free. At this time, the electrical energy from the grid is sent to the flywheel energy storage unit 13 via the converter unit 12 and stored in the form of kinetic energy.

[0045] In this embodiment, the converter unit 12 includes a DC bus, a grid-side converter, a machine-side converter, and a transformer. The DC side of the grid-side converter and the DC side of the machine-side converter are connected to the DC bus. The AC side of the grid-side converter is connected to the power grid through the transformer. The AC side of the machine-side converter is connected to the flywheel energy storage unit. The machine-side converter supplies power to the DC bus based on machine-side rectification control commands, and the grid-side converter supplies power to the power grid based on grid-side inverter control commands.

[0046] like Figure 2 As shown, converter A is a grid-side converter, and converter B is a generator-side converter. Both converter A and converter B receive commands from the controller to operate in different modes. These modes include rectification mode or inverter mode. A capacitor is connected to the DC side of converter A; the positive terminal of the capacitor is connected to the positive terminal of the DC bus, and the negative terminal is connected to the negative terminal of the DC bus. The DC side of converter A is connected to the DC bus. The AC side of converter A is connected to the grid via a transformer. The DC side of converter B is connected to the DC bus, and the AC side of converter B is connected to the flywheel energy storage unit 13.

[0047] In this embodiment, the generator-side converter supplies power to the DC bus based on generator-side rectification control commands, and the grid-side converter supplies power to the grid based on grid-side inverter control commands.

[0048] Specifically, the energy conversion and transfer of the flywheel energy storage unit 13 is accomplished through the coordinated control of the controller, converter A, and converter B. When the flywheel is functioning normally and without faults, in the energy storage phase, converter A receives rectification control commands from the grid side and operates in rectification mode, converting electrical energy from the grid into direct current (DC). Converter B receives inverter control commands from the inverter side and operates in inverter mode, converting the DC bus electrical energy into a three-phase AC voltage with adjustable frequency and amplitude to drive the motor in the flywheel energy storage unit 13. During the energy storage phase, converter B outputs a three-phase voltage with continuously increasing amplitude and frequency, gradually increasing the flywheel speed until the target speed is reached, at which point the electrical energy is converted into the flywheel's kinetic energy and stored.

[0049] When the flywheel experiences instability, the flywheel energy storage unit 13 is in the power generation stage. Converter B receives rectification control commands from the generator side and operates in rectification mode. The amplitude and frequency of the output voltage of converter B continuously decrease. The angular velocity of the synchronous rotating magnetic field of the motor (e.g., an asynchronous motor) in the flywheel energy storage unit 13 is lower than the angular velocity of the flywheel rotor. The asynchronous motor operates in generator braking mode, and the flywheel speed gradually decreases, continuously converting kinetic energy into electrical energy which is then sent to the DC bus. Converter A receives inverter control commands from the grid side and operates in inverter mode. Converter A converts the electrical energy from the DC bus into three-phase AC power with a frequency of 50Hz and independently adjustable voltage and phase, which is then transmitted to the grid via a transformer.

[0050] In this embodiment, as Figure 2 As shown, the flywheel energy storage unit includes a motor and a flywheel rotor. The flywheel rotor is used to drive the motor to generate electricity when the machine-side converter receives the machine-side rectification control command.

[0051] In this embodiment, the motor and the flywheel rotor rotate coaxially.

[0052] In this embodiment, when the inverter B receives the inverter control command on the receiving side and is in inverter mode, the motor is in motor mode, and the motor stores the electrical energy from the inverter B in the form of kinetic energy in the flywheel rotor. When the inverter B receives the rectification control command on the receiving side and is in rectification mode, the motor is in generator mode, and the motor converts the kinetic energy in the flywheel rotor into electrical energy and sends it to the inverter B.

[0053] In this embodiment, the energy dissipation circuit unit 14 is connected to the DC bus, and the energy dissipation circuit unit 14 is used to discharge when an energy dissipation start command is received.

[0054] In this embodiment, as Figure 2 As shown, the energy-consuming circuit unit 14 includes a thyristor and a discharge resistor, and the positive terminal of the DC bus is connected to the negative terminal of the DC bus through the thyristor and the discharge resistor.

[0055] In this embodiment, the thyristor is used to control the operating state of the energy dissipation circuit unit 14. When the thyristor is turned on, the energy dissipation circuit unit 14 operates normally (i.e., the discharge resistor discharges normally), and when the thyristor is turned off, the energy dissipation circuit unit 14 stops operating.

[0056] In this embodiment, the control terminal of the thyristor is connected to the control unit 11. When the thyristor receives the power consumption start command, the thyristor is turned on and the discharge resistor starts to discharge.

[0057] In this embodiment, the discharge resistor is a zinc oxide nonlinear resistor.

[0058] In this embodiment, the DC braking unit 15 is connected to the DC bus and is used to brake the flywheel rotor when a braking start command is received.

[0059] In this embodiment, as Figure 2 As shown, the DC braking unit 15 includes a transistor, an external resistor, and a braking winding. The positive terminal of the DC bus is connected to the negative terminal of the DC bus via the transistor, the external resistor, and the braking winding.

[0060] In this embodiment, the transistor is used to control the operation of the DC braking unit 15. When the transistor is turned on, the DC braking unit 15 operates normally (i.e., normally brakes the flywheel rotor); when the transistor is turned off, the DC braking unit 15 stops operating.

[0061] In this embodiment, the transistor is also used to regulate the braking current through the braking winding. Specifically, the braking current is adjusted by controlling the transistor's on-time and off-time, meaning the transistor operates in an intermittent state. Furthermore, the selection of the braking current is also adjusted based on the flywheel rotor's heating status. When the temperature inside the flywheel rotor housing reaches a temperature threshold, the transistor is turned off; when the temperature inside the flywheel rotor housing falls below the temperature threshold, the transistor is turned back on.

[0062] In this embodiment, the control terminal of the transistor is connected to the control unit 11. When the transistor receives the braking start command, the transistor is turned on, and the DC braking unit 15 begins to brake the flywheel rotor.

[0063] In this embodiment, the transistor is an insulated-gate bipolar transistor (IGBT). The control terminal of the transistor is the gate of the IGBT.

[0064] In this embodiment, an external resistor is used to limit the current to protect the DC braking unit 15. The external resistor may be, for example, 0.1 ohms.

[0065] In this embodiment, the braking winding is used to generate braking torque through interaction with the flywheel rotor.

[0066] In this embodiment, the braking winding is a coil winding disposed in the flywheel rotor housing.

[0067] In this embodiment, after the transistor is turned on, the braking torque of the entire rotating system consisting of the flywheel rotor and the motor consists of two parts. One part is generated by the interaction between the stator and rotor of the generator when the motor is operating in generator braking mode. The other part is generated by the interaction between the braking winding in the flywheel housing and the flywheel rotor. In addition, the DC braking unit 15 operates using the electrical energy of the DC bus, and the electrical energy of the DC bus comes from the motor in generator mode. Therefore, the current of the braking winding in the flywheel housing is provided by the motor in generator mode.

[0068] In this embodiment, as Figure 2 As shown, the DC braking unit also includes a boost circuit, which is located between the transistor and the external resistor. The boost circuit is used to adjust the voltage across the braking winding. The boost circuit typically controls the voltage across the braking winding to 100V.

[0069] In this embodiment, the boost circuit can be selected as a boost circuit.

[0070] In some embodiments of this disclosure, the energy storage flywheel energy release device 10 further includes a temperature monitoring unit connected to the control unit. The temperature monitoring unit is used to monitor the temperature inside the flywheel rotor housing and send it to the control unit. The control unit is also used to determine the temperature and a temperature threshold, and control the transistor to turn off when the temperature reaches the temperature threshold.

[0071] In some embodiments of this disclosure, the flywheel energy storage unit 13 further includes a cooling module. Specifically, when the brake winding is turned on, a current is induced in the flywheel rotor. When the current flows through the flywheel rotor, it generates a lot of heat. When the temperature inside the flywheel rotor housing reaches the temperature threshold, the cooling module injects cooled helium into the flywheel rotor housing. Through the circulation of helium, the heat generated by the induced current in the flywheel rotor is carried away, and the heat-exchanged helium is sent to a centralized water cooling system for cooling, and then injected back into the flywheel rotor housing for circulation until the temperature is lower than the temperature threshold.

[0072] Specifically, in combination Figure 2 The energy release process of the energy storage flywheel energy release device in this embodiment is as follows:

[0073] The motor speed is monitored. If the motor speed is greater than 3000 rpm, when a flywheel instability fault is detected, the amplitude and frequency of the output voltage of converter B continuously decrease. The angular velocity of the synchronous rotating magnetic field of the asynchronous motor is lower than the angular velocity of the flywheel rotor. The asynchronous motor operates in generator braking mode, and the flywheel speed gradually decreases, continuously converting kinetic energy into electrical energy and sending it to the DC bus. At this time, the thyristor is triggered, and the DC bus discharges through the zinc oxide nonlinear resistor. Converter A sends the electrical energy from the DC bus to the power grid via a transformer. In this case, the electrical energy in the flywheel energy storage unit 13 is released in two ways: one way is sent to the power grid, and the other way is released using the zinc oxide nonlinear resistor.

[0074] When both the motor speed and the flywheel rotor speed are below 3000 rpm, the conducting transistor is triggered. After the transistor is triggered, the constant magnetic field generated by the DC current in the braking winding interacts with the induced current on the surface of the flywheel rotor, thereby generating braking torque. The magnitude of the braking torque is related to the magnitude of the DC power supply and the motor speed. As the speed decreases, the braking torque increases sharply, reaching its maximum value when the speed drops to 0.1-0.2 synchronous speed (i.e., 300-600 rpm). In this case, the electrical energy in the flywheel energy storage unit 13 is released in three ways: one is sent to the power grid, one is released using the zinc oxide nonlinear resistor, and the other is supplied to the braking winding to brake the flywheel rotor.

[0075] After the brake winding is turned on, the temperature inside the flywheel rotor housing is monitored. When the temperature inside the flywheel rotor housing reaches the temperature threshold, cooled helium is injected into the flywheel rotor housing. Through the circulation of helium, the heat generated by the induced current of the flywheel rotor is carried away. After heat exchange, the helium is sent to a centralized water cooling system for cooling, and then injected into the flywheel rotor housing for circulation until the temperature inside the flywheel rotor housing is lower than the temperature threshold.

[0076] When the temperature inside the flywheel rotor housing reaches the temperature threshold, the transistor is triggered to turn off. When the helium gas carries away the heat and the temperature inside the flywheel rotor housing falls below the temperature threshold, the transistor is turned back on.

[0077] In this embodiment of the energy storage flywheel energy release device, there are a control unit, a converter unit, a flywheel energy storage unit, an energy dissipation circuit unit, and a DC braking unit. The control unit is connected to the converter unit, the flywheel energy storage unit, the energy dissipation circuit unit, and the DC braking unit, respectively. The control unit is used to generate machine-side rectification control commands and grid-side inverter control commands when the flywheel experiences instability, and to acquire the motor speed and flywheel rotor speed. Based on the motor speed or the flywheel rotor speed, it generates an energy dissipation start command or a braking start command. The converter unit includes a DC bus, a grid-side converter, a machine-side converter, and a transformer. The DC side of the grid-side converter and the DC side of the machine-side converter are connected to... The DC bus is connected, the AC side of the grid-side converter is connected to the grid via a transformer, and the AC side of the machine-side converter is connected to the flywheel energy storage unit. The machine-side converter supplies power to the DC bus based on the machine-side rectification control command, and the grid-side converter supplies power to the grid based on the grid-side inverter control command. The flywheel energy storage unit includes a motor and a flywheel rotor. The flywheel rotor is used to drive the motor to generate electricity when the machine-side converter receives the machine-side rectification control command. The energy dissipation circuit unit is connected to the DC bus and is used to discharge when it receives the energy dissipation start command. The DC braking unit is connected to the DC bus and is used to brake the flywheel rotor when it receives the braking start command. In this scenario, when the flywheel experiences instability, the converter unit transfers electrical energy to the grid, the energy dissipation circuit unit consumes some of the electrical energy in the flywheel energy storage unit, and the DC braking unit assists in braking the flywheel rotor. Compared to the prior art which relies solely on the braking system to brake the flywheel during a fault, the device disclosed herein can promptly release and transfer the flywheel's kinetic energy to avoid personal injury and equipment damage.

[0078] The following are embodiments of the method disclosed herein. For details not disclosed in the embodiments of the method disclosed herein, please refer to the embodiments of the device disclosed herein. The embodiments of the method disclosed herein propose an energy release method for an energy storage flywheel. This energy release method uses the energy storage flywheel energy release device described in the above-described device embodiments for water quality deterioration early warning. The energy storage flywheel energy release method of this disclosure can be simply referred to as an early warning method.

[0079] Figure 3 A flowchart illustrating an energy release method for an energy storage flywheel provided in an embodiment of this disclosure is shown. Figure 3 As shown, the energy release method of the energy storage flywheel includes:

[0080] Step S11: When the flywheel experiences instability, the control unit generates machine-side rectification control commands and grid-side inverter control commands.

[0081] In step S12, the generator-side converter supplies power to the DC bus based on the generator-side rectification control command, and the grid-side converter supplies power to the grid based on the grid-side inverter control command. When the generator-side converter receives the generator-side rectification control command, the flywheel rotor drives the motor to generate electricity.

[0082] In step S13, the control unit also acquires the motor speed and flywheel rotor speed, and generates an energy-consuming start command or a braking start command based on the motor speed or flywheel rotor speed.

[0083] In step S14, the energy dissipation circuit unit discharges when it receives the energy dissipation start command, and the DC braking unit brakes the flywheel rotor when it receives the braking start command.

[0084] The specific details of steps S11 to S14 can be found in the relevant descriptions in the above device embodiments, and will not be repeated here.

[0085] In embodiments of this disclosure, the energy release method of the energy storage flywheel further includes: the control unit acquiring the temperature inside the flywheel rotor housing, determining the temperature and a temperature threshold, and controlling the transistor in the DC braking unit to turn off when the temperature reaches the temperature threshold.

[0086] It should be noted that the foregoing explanation of the embodiment of the energy storage flywheel energy release device also applies to the energy storage flywheel energy release method of this embodiment, and will not be repeated here.

[0087] The sequence numbers of the embodiments disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0088] In the energy release method of the energy storage flywheel disclosed herein, when the flywheel experiences an instability fault, the control unit generates a machine-side rectification control command and a grid-side inverter control command; the machine-side converter supplies power to the DC bus based on the machine-side rectification control command, and the grid-side converter supplies power to the grid based on the grid-side inverter control command; the flywheel rotor drives the motor to generate electricity when the machine-side converter receives the machine-side rectification control command; the control unit also acquires the motor speed and the flywheel rotor speed, and generates an energy-consuming start command or a braking start command based on the motor speed or the flywheel rotor speed; the energy-consuming circuit unit discharges when it receives the energy-consuming start command, and the DC braking unit brakes the flywheel rotor when it receives the braking start command. In this scenario, when the flywheel experiences instability, the converter unit transfers electrical energy to the grid, the energy dissipation circuit unit consumes some of the electrical energy in the flywheel energy storage unit, and the DC braking unit assists in braking the flywheel rotor. Compared to existing technologies that rely solely on the braking system to brake the flywheel during a fault, the method disclosed herein can promptly release and transfer the flywheel's kinetic energy to prevent personal injury and equipment damage.

[0089] The accompanying drawings show structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not drawn to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0090] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this disclosure can be achieved, and this disclosure does not impose any limitations herein.

[0091] The specific embodiments described above do not constitute a limitation on the scope of protection of this disclosure. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. An energy storage flywheel energy release device, characterized in that, It includes a control unit, a converter unit, a flywheel energy storage unit, an energy dissipation circuit unit, and a DC braking unit. The control unit is connected to the converter unit, the flywheel energy storage unit, the energy dissipation circuit unit, and the DC braking unit, respectively. The control unit is used to generate machine-side rectification control commands and grid-side inverter control commands when the flywheel experiences instability, and to acquire the motor speed and flywheel rotor speed, and to generate energy-consuming start commands or braking start commands based on the motor speed or flywheel rotor speed. The converter unit includes a DC bus, a grid-side converter, a generator-side converter, and a transformer. The DC side of the grid-side converter and the DC side of the generator-side converter are connected to the DC bus. The AC side of the grid-side converter is connected to the power grid through the transformer. The AC side of the generator-side converter is connected to the flywheel energy storage unit. The generator-side converter supplies power to the DC bus based on the generator-side rectification control command, and the grid-side converter supplies power to the power grid based on the grid-side inverter control command. The flywheel energy storage unit includes a motor and a flywheel rotor. The flywheel rotor is used to drive the motor to generate electricity when the machine-side converter receives the machine-side rectification control command. The energy-consuming circuit unit is connected to the DC bus, and the energy-consuming circuit unit is used to discharge when the energy-consuming start command is received; The DC braking unit is connected to the DC bus and is used to brake the flywheel rotor when the braking start command is received.

2. The energy storage flywheel energy release device as described in claim 1, characterized in that, The energy-consuming circuit unit includes a thyristor and a discharge resistor, and the positive terminal of the DC bus is connected to the negative terminal of the DC bus via the thyristor and the discharge resistor.

3. The energy storage flywheel energy release device as described in claim 2, characterized in that, The discharge resistor is a zinc oxide nonlinear resistor.

4. The energy storage flywheel energy release device as described in claim 1, characterized in that, The DC braking unit includes a transistor, an external resistor, and a braking winding. The positive terminal of the DC bus is connected to the negative terminal of the DC bus via the transistor, the external resistor, and the braking winding.

5. The energy storage flywheel energy release device as described in claim 4, characterized in that, The transistor is an insulated gate bipolar transistor.

6. The energy storage flywheel energy release device as described in claim 5, characterized in that, The braking winding is a coil winding installed in the flywheel rotor housing.

7. The energy storage flywheel energy release device as described in claim 4, characterized in that, The DC braking unit also includes a boost circuit, which is disposed between the transistor and the external resistor.

8. The energy storage flywheel energy release device as described in claim 4, characterized in that, The energy storage flywheel energy release device also includes a temperature monitoring unit, which is connected to the control unit. The temperature monitoring unit is used to monitor the temperature inside the flywheel rotor housing and send it to the control unit. The control unit is also used to determine the temperature and a temperature threshold, and control the transistor to turn off when the temperature reaches the temperature threshold.

9. A method for recovering braking energy based on the energy storage flywheel energy release device as described in any one of claims 1-8, characterized in that, include: When the flywheel experiences instability, the control unit generates machine-side rectification control commands and grid-side inverter control commands. The generator-side converter supplies power to the DC bus based on the generator-side rectification control command, and the grid-side converter supplies power to the grid based on the grid-side inverter control command. The flywheel rotor drives the motor to generate electricity when the generator-side converter receives the generator-side rectification control command. The control unit also acquires the motor speed and flywheel rotor speed, and generates an energy-consuming start command or a braking start command based on the motor speed or flywheel rotor speed; The energy dissipation circuit unit discharges when it receives the energy dissipation start command, and the DC braking unit brakes the flywheel rotor when it receives the braking start command.

10. The method as described in claim 9, characterized in that, Also includes: The control unit acquires the temperature inside the flywheel rotor housing, determines the temperature against a temperature threshold, and controls the transistor in the DC braking unit to turn off when the temperature reaches the temperature threshold.

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