Device and method for increasing the moment of inertia of a flywheel of a new energy phase modifier

Abstract

The present application relates to a device and method for improving the moment of inertia of a new energy phase modifier combined with a flywheel, and belongs to the technical field of intelligent grid regulation. The device is provided with a phase modifier and a flywheel, and one end of the rotating shaft of the phase modifier is connected to the flywheel through a clutch type coupling. Thus, the engagement or separation of the flywheel and the rotating shaft of the phase modifier can be controlled through the clutching state of the clutch type coupling, and the moment of inertia of the phase modifier can be adjusted to meet the actual requirements. The method uses an intelligent algorithm to analyze the real-time state of the power grid based on real-time collected basic data and control targets and control modes, and performs cyclic control. The method is provided with normal control mode, voltage regulation mode, frequency regulation mode and abnormal protection mode, and has fast response speed and high regulation accuracy.

Description

TECHNICAL FIELD

[0001] The application relates to a device and method for improving the rotational inertia of a new energy phase modifier combined with a flywheel, and belongs to the technical field of intelligent power grid regulation. BACKGROUND

[0002] In the field of new energy power generation, a phase modifier serves as an important reactive power compensation device and plays a key role in maintaining the stability and voltage quality of a power system. However, due to the limitations of its own structure and design, the rotational inertia of the phase modifier in practice is relatively small, which results in its weak performance in dealing with rapid power changes and active regulation in the power system. The small rotational inertia means that the phase modifier cannot provide sufficient inertial support to the system, and it cannot effectively absorb or release energy in a short time, which makes it difficult to meet the demand of the power system for rapid and accurate active regulation in some scenarios. SUMMARY

[0003] The purpose of the application is to improve the rotational inertia of the phase modulation system to facilitate the rapid and accurate implementation of power system related regulation.

[0004] The technical solution of the application is a device for improving the rotational inertia of a new energy phase modifier combined with a flywheel, which comprises a phase modifier and a flywheel. One end of the phase modifier shaft (or phase modifier main shaft, or phase modifier shaft) is connected to the flywheel (flywheel shaft) through a clutch type coupling. The engagement (or coupling) or separation of the flywheel and the phase modifier shaft can be controlled through the clutch state of the clutch type coupling, thereby adjusting the rotational inertia of the phase modifier to meet the actual demand.

[0005] Preferably, the outer side of the flywheel (the end of the flywheel shaft not connected to the phase modifier, or the flywheel side generator connection end of the flywheel shaft) is connected to a flywheel side generator. The output of the flywheel side generator is connected to the power grid through a flywheel side transformer device.

[0006] Preferably, the flywheel side transformer device is a bidirectional transformer device, which can control the flywheel side generator to be in different working states (generating or motoring) under different conditions or control requirements.

[0007] Preferably, the connection between the outer side of the flywheel and the flywheel side generator is that the flywheel shaft (flywheel side generator connection end of the flywheel shaft) is connected to the input shaft of the flywheel side generator through a second clutch type coupling, thereby controlling the connection state (engagement or separation) of the flywheel and the flywheel side generator through the second clutch type coupling.

[0008] Preferably, the clutch coupling comprises a first side member, a second side member and a sliding member arranged coaxially (axes are arranged on the same line), the sliding member is arranged between the first side member and the second side member, the sliding member connecting side of the first side member and the second side member is respectively provided with a first side internal spline and a second side internal spline, and the two sides of the sliding member are respectively provided with a corresponding first side external spline and a second side external spline, within the stroke range of the sliding member, the first side external spline always keeps the spline connection with the first side internal spline, and the second side external spline and the second side internal spline are engaged with each other when the sliding member is in the engagement position, and are separated from each other when the sliding member is in the separation position.

[0009] Preferably, the first side external spline and the first side internal spline are straight splines, and the second side external spline and the second side internal spline are thread splines.

[0010] Preferably, the first side member is provided with a guide column, the sliding member is sleeved on the guide column through an axial sliding hole, an oil cavity is arranged between the sliding hole and the guide column, the sliding hole and the guide column are sealingly fitted on both sides of the oil cavity (in the whole stroke range of the sliding member, the sealingly fitted on both sides of the oil cavity is always ensured), the oil cavity is connected with an oil supply pipeline and an oil return pipeline, a reset spring is arranged between the first side member and the sliding member, and / or a reset spring is arranged between the second side member and the sliding member, when the clutch coupling is switched, the sliding member is pushed to the engagement position by the high-pressure liquid pressure injected into the oil cavity, and the sliding member is pushed to the separation (or disconnection) position by the reset spring.

[0011] Further, the device is provided with a control system for controlling the cooperative work of each part.

[0012] The control system analyzes and judges the real-time working state according to the real-time obtained relevant basic data (such as: power grid voltage, frequency, speed of the phase modifier and the flywheel, vibration value and other monitoring data), and implements control according to the real-time working state and the set control target and control mode. For example, the control of the clutching state of the clutch type coupling, the realization of the engagement or separation between the flywheel and the phase modifier, the control of the clutching state of the second clutch type coupling (if provided), the realization of the engagement or separation between the flywheel and the flywheel side generator, the control of the excitation current of the phase modifier connected to the phase modifier, and the realization of the control of the working state of the phase modifier. In the flywheel charging process in the normal control mode, the adjustment of the excitation current of the phase modifier is the core means of matching the calculated charging power: increasing the excitation current can increase the active output of the phase modifier and promote the angular acceleration of the flywheel to increase the charging power; reducing the excitation current can reduce the active output of the phase modifier and reduce the angular acceleration of the flywheel to reduce the charging power, and the real-time monitored flywheel speed, speed difference, vibration value and other data need to be combined to build a closed loop feedback to ensure that the charging power accurately meets the calculated value. At the same time, the control parameters or working modes of the flywheel side power transformation device are controlled to realize the control of the working state of the flywheel side generator. The control modes of the phase modifier, the flywheel side power transformation device, the clutch type coupling and the second clutch type coupling can adopt the existing technology.

[0013] The control system can set a plurality of sensors and / or other forms of data acquisition devices according to the control and monitoring requirements to obtain various basic data required for control, and if necessary, to obtain other data required for monitoring.

[0014] The method for improving the moment of inertia of the new energy phase modifier combined with the flywheel adopts any one of the devices for improving the moment of inertia of the new energy phase modifier combined with the flywheel disclosed in the present application to implement power system regulation, and realizes the engagement or separation of the flywheel and the phase modifier by switching the state of the clutch type coupling.

[0015] In the engaged state of the clutch type coupling, the phase modifier can drag the flywheel to store energy, or the flywheel releases inertia to assist the phase modifier.

[0016] In the disengaged state of the clutch type coupling, the phase modifier and the flywheel work independently. In this case, the phase modifier can independently implement reactive power regulation, and the flywheel can independently release energy to the power grid or not.

[0017] Preferably, the normal control mode, the voltage regulation mode, the frequency regulation mode and the abnormal protection mode are provided.

[0018] Further, when the power grid is in a normal state (set normal range), the normal control mode is adopted, the clutch type coupling is kept engaged, and the phase modifier drags the flywheel to accelerate and store energy.

[0019] Further, when the grid voltage is abnormal (the absolute value of the difference between the actual voltage and the rated voltage exceeds the limit), the voltage regulation mode is adopted, the clutch coupling is disconnected, and the phase modifier outputs the reactive power according to the regulation requirement.

[0020] Further, when the grid frequency is abnormal (the absolute value of the difference between the actual frequency and the rated frequency exceeds the limit), the frequency regulation mode is adopted, the clutch coupling is engaged, when the actual frequency is lower than the rated frequency of the grid, the flywheel side generator works in the generator state, and the flywheel releases energy to the grid; when the actual frequency is higher than the rated frequency of the grid, the flywheel absorbs energy, and the flywheel side generator works in the motor state, and the flywheel absorbs energy from the grid.

[0021] Further, when the trigger abnormal protection (the grid abnormality reaches a certain degree), the abnormal protection mode is adopted, the alarm signal is output, the clutch coupling is disconnected, the phase modifier operates independently, the reactive power output is limited to the level of only maintaining the basic voltage, and the flywheel enters the free deceleration state until the speed drops to the safe range.

[0022] During operation, the cycle control can be implemented, the absolute value ΔU of the difference between the actual voltage and the rated voltage of the grid, the absolute value Δf of the difference between the actual frequency and the rated frequency of the grid, the absolute value Δn of the difference between the actual speed of the phase modifier and the actual speed of the flywheel, and the flywheel energy storage coefficient S f are calculated according to the real-time monitoring data (for example, the basic data collected in real time), the flywheel energy storage coefficient is equal to the square of the ratio of the actual speed of the flywheel to the rated maximum speed of the flywheel, and the real-time ΔU, Δf, Δn and S f are calculated, the state judgment is performed, and the state adjustment (including maintenance) is performed according to the following modes:

[0023] 1) If the grid is in a stable state (normal state) and Δn≦1, S f <60% (or other set value, which can be set according to actual needs), the clutch coupling is engaged, and the phase modifier drives the flywheel to rotate;

[0024] 2) If the grid is in a stable state (normal state) and Δn≦1, S f ≧60% (or other set value, which can be set according to actual needs), the clutch coupling is engaged, the phase modifier stabilizes the reactive power output, and the flywheel is on standby;

[0025] 3) If the voltage fluctuation (generally exceeding the limit) and Δn>3% (the same below), the clutch coupling is engaged, the phase modifier adjusts the reactive power output according to the actual requirement, and if necessary, the flywheel side generator can be in the generator working state, and its output (reactive power output) is connected to the grid;

[0026] 4) If voltage emergency (serious overrun) and Δn>10%, the clutch coupling is disconnected, the phase modifier fully outputs reactive power, and the flywheel side generator is in the generator working state, and its output (reactive output) is connected to the power grid;

[0027] 5) If Δf>0.05, and S f ≧30% (or other set values, which can be set according to actual needs), the clutch coupling is engaged, the flywheel side generator is in the generator working state or the motor working state according to the actual frequency (lower or higher than the rated frequency), and its output (active output or input) is connected to the power grid, and the flywheel releases energy to the power grid or absorbs energy from the power grid, and if necessary, the phase modifier can output or consume active power to assist frequency regulation;

[0028] 6) If Δn>1, and / or, the vibration overrun (general overrun), the clutch coupling is disconnected, and a warning is sent out, and in this case, the existing technical equipment can be unloaded;

[0029] 7) If Δn>3, and / or, the vibration seriously overruns, the clutch coupling is forcibly disconnected, and a warning is sent out, and in this case, the existing technical equipment should be stopped and / or locked.

[0030] The beneficial effects of the present application are: since the flywheel is provided and connected to the phase modifier main shaft through the clutch coupling, the flywheel can be connected to or separated from the phase modifier according to actual needs to meet different requirements for the rotational inertia of the phase modifier under different conditions; since the other side of the flywheel can also be connected to the flywheel side generator and the corresponding power transformation device, the flywheel mechanical energy storage can be converted into electrical output, connected to the power grid at a suitable frequency and phase, and cooperated with the power generation system to adjust the abnormal conditions of the power grid, improve the adjustment capacity and speed, and also the flywheel side generator can work in the motor state to absorb active power from the power grid to meet different adjustment requirements, and the switching speed of the clutch coupling is fast, which can effectively improve the response speed to the power grid. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a schematic view of a structure related to the phase modifier and the flywheel in the device of the present application;

[0032] Figure 2 is a schematic view of a structure related to the flywheel and the flywheel side generator in the device of the present application;

[0033] Figure 3 is a schematic view of a structure and working principle of the clutch coupling of the present application;

[0034] Figure 4 is a schematic view of an oil chamber oil circuit of the present application;

[0035] Figure 5 is a flow chart of the method of the present application in one embodiment.

[0036] Marked in the figure: 1, drive end bearing; 2, phase modifier; 3, non-drive end bearing; 4, clutch coupling; 5, flywheel; 6, flywheel guard; 7, flywheel side bearing; 8, flywheel side generator; 9, bidirectional converter; 10, bidirectional inverter; 11, flywheel shaft extension on the other side; 12, flywheel side generator output; 13, DC bus; 14, AC bus; 41, first side member; 42, first side inner spline; 43, bidirectional limiting plate; 44, sliding member; 45, oil cavity; 46, first side outer spline; 47, second side outer spline; 48, second side member; 49, second side inner spline. DETAILED DESCRIPTION

[0037] Referring to Figures 1 to 4 , the present application mainly solves the problems of small rotational inertia, weak active regulation ability and limited working range of traditional phase modifiers by combining flywheel 5 with phase modifier 2. Flywheel, as a mechanical device with large rotational inertia, can make up for the shortcomings of phase modifier. Through clutch coupling 4, flywheel is connected with the main shaft of phase modifier, realizing the functional complementation of the two. In practical application, this method not only significantly improves the rotational inertia of phase modifier and enhances its active regulation ability, but also expands the working range of phase modifier, enabling it to operate stably and efficiently under a wider range of power conditions.

[0038] In order to make flywheel and phase modifier work together, appropriate control system is equipped. Through the control system, the running state and power change of power system can be monitored in real time, and the intervention and exit of flywheel can be accurately controlled according to these information, so as to realize the dynamic optimization of rotational inertia and active regulation ability of phase modifier. When appropriate, the existing control system related to phase modifier can be used to realize related data processing and control with the support of software.

[0039] According to the power demand and working conditions of phase modifier, flywheel with appropriate material and size can be selected. For example, for phase modifier with high power and high frequency regulation demand, flywheel made of alloy material with high density and strength can be selected, and its diameter and thickness can be appropriately increased to improve the rotational inertia.

[0040] The prior art can be used to set up real-time monitoring devices and various data acquisition devices (e.g., sensors for various real-time operating parameters) based on control requirements, and intelligent control algorithms can be used for data processing / operation based on existing intelligent technology. The real-time monitoring device monitors the voltage, current, frequency and other parameters related to power system regulation, as well as the rotational speed, torque and other operating state data of the phase modifier in real time through a number of data acquisition devices. In general, it should include: voltage and current sensors for real-time monitoring of the power system, which can use electromagnetic sensors to meet the requirements of strong anti-interference ability, wide range, high precision (e.g., 0.2S level or higher) and fast response (e.g., microsecond level); speed sensors of the phase modifier, which can use photoelectric encoding sensors to have high precision and can measure the speed and phase of the phase modifier, and under the existing technical background, the resolution can reach 0.1r / min level, ensuring the accuracy of synchronous speed monitoring; torque sensors, which can use magnetic elastomer dynamic sensors to monitor torque (e.g., flywheel torque and phase modifier generator torque) in real time through magnetic permeability change rate. In addition, in appropriate cases, data (partially or entirely) can also come from existing power system and phase modifier related data acquisition devices / related data output. These sensors will transmit related data to the real-time monitoring device in real time, which will be analyzed and processed by the monitoring device, and the data will be transmitted to the control device in real time. The control device runs an intelligent control algorithm to form control data / control instructions under corresponding conditions. Based on the intelligent control algorithm, the control device accurately calculates the control instructions (e.g., controlling the connection of the flywheel, controlling the output power of the flywheel, etc.) according to the monitoring data (real-time data) sent by the real-time monitoring device, in combination with the preset control target (e.g., maintaining the voltage within ±3% of the rated value, the frequency within 50Hz±0.05Hz, and the rotational speed of the phase modifier synchronized, etc.), and realizes real-time control through various related execution mechanisms (e.g., drive mechanism of the clutch type coupling, exciter, etc.). For example, when the power system (e.g., power grid) experiences sudden voltage, frequency and / or power fluctuations, the control system quickly controls the flywheel to release the stored kinetic energy, helping the phase modifier to respond quickly and stabilize the system frequency.

[0041] During installation and commissioning, strict accuracy control and performance testing should be carried out. Ensure that the concentricity error of the flywheel and the main shaft is within ≤0.05mm, and the lubrication and heat dissipation of the transmission system are good. Through simulation of various actual operating conditions, the overall performance of the device is tested comprehensively to verify its stability and reliability under different conditions. Lubrication, heat dissipation, safety protection and other supporting and auxiliary facilities can be set up according to the existing technology.

[0042] The flywheel and the phase modifier are connected through a clutch coupling. The clutch coupling (and the second clutch coupling described later) can adopt any suitable prior art. As a preferred embodiment, it can be a rigid coupling (for example, a coupling that achieves engagement through gear meshing), which can be suitable for various power scenarios, has the characteristics of fast response speed, low loss, alleviation of impact load, reduction of vibration transmission, and prolongation of bearing and rotor life. The clutch drive can be achieved by hydraulic or other suitable means, and the coupling of the phase modifier shaft and the flywheel shaft through the clutch coupling can be achieved according to prior art. For example, the clutch coupling can be connected with the flywheel side flange and the phase modifier side flange through bolts and clamping grooves respectively. In the power grid with strong fluctuation of wind power and photovoltaic power, the flywheel needs to be frequently put into and taken out, and in the hydraulic drive mode, the buffering effect of the pressure liquid (hydraulic oil) in the rigid coupling can reduce equipment fatigue and support various working conditions with frequent dynamic response. The fastening condition of the connecting parts, the wear degree of the flywheel, and the working state of the control system can be checked regularly. The online monitoring technology can be used to master the running condition of the device in real time, and the possible faults and hidden dangers can be found and handled in time.

[0043] Figure 3A rigid connection (spline connection) clutch coupling is shown, which can be used as the clutch coupling and the second clutch coupling (if provided) of the application. The coupling is provided with a first side member 41, a second side member 48 and a sliding member 44, all of which are of a rotationally symmetrical structure (for example, a cylindrical structure and / or a structure with a ring-shaped cross section) and coaxially arranged (the axes are on the same line). The first side member and the second side member are fixedly connected to the shaft ends (the corresponding side phase modifier shaft end and the flywheel shaft end) to be connected by the coupling, respectively. For example, the first side member is coaxially fixedly installed at the shaft end of the flywheel shaft, and the second side member is coaxially fixedly installed at the shaft end of the flywheel side generator. An axial hole (blind hole or through hole) for connecting with the shaft end can be provided at the shaft end side of the first side member and the second side member, which is tightly sleeved on the corresponding shaft end and fixed on the corresponding shaft end by interference fit or threaded fastening, etc. The connecting side (the opposite side of the two members) of the first side member and the second side member is provided with an inner spline, which can be referred to as a first side inner spline 42 and a second side inner spline 49, respectively. The axial two sides of the sliding member are respectively provided with a first side outer spline 46 and a second side outer spline 47 which are adapted to the first side inner spline and the second side inner spline, and within the (sliding) stroke range of the sliding member, the first side outer spline always maintains the spline connection with the first side inner spline, and the axial length and position of the first side outer spline and / or the first side inner spline can be reasonably set to realize this connection maintenance. The second side outer spline and the second side inner spline are connected (or engaged) with each other when the sliding member slides to the engagement (clutch coupling engagement) position, and are separated from each other when the sliding member slides to the separation (clutch coupling disconnection, or separation) position, and the axial length and position of the second side outer spline and / or the second side inner spline can be reasonably set to realize the change of the connection state with the position / movement of the sliding member. Thus, by controlling the sliding (position) of the sliding member, the clutching of the clutch coupling can be realized.

[0044] As a preferred embodiment, the first side outer spline and the first side inner spline are straight splines (or linear splines, common splines), and the second side outer spline and the second side inner spline are thread splines (or helical splines). When changing from the disengaged state to the engaged state, the axial movement direction of the sliding member is consistent with the axial movement direction of the thread rotation, and the thread direction can be determined in sequence. By setting the second side spline as a thread spline, the deficiencies of rigid connection in positioning accuracy and impact resistance are compensated for, providing conditions for precise action and reliable force transmission of the clutch-type coupling. This includes: (1) guiding engagement / disengagement: when the driving gear is pushed to move axially in the follow-up clutch-type coupling, the helical key groove guides the driving gear to rotate slightly along the helical track, ensuring precise positioning of the driving gear and the driven gear (compensating for small coaxiality deviation), and avoiding engagement jamming; (2) enhancing torque transmission stability: when transmitting torque, the slope of the helical key groove converts axial force into circumferential friction force, preventing the driving gear from slipping with the main shaft, and ensuring efficient torque transmission (especially at high speed); (3) buffering impact: the elastic deformation of the helical structure can absorb transient torque impact (such as sudden disturbance of the power grid), reducing mechanical stress on the shaft system and prolonging the service life of the equipment.

[0045] The first side member is provided with an axially extending guide column, and the guide column is coaxial with the first side member. The sliding member is provided with a sliding hole (a hole for sliding), and the sliding hole is coaxial with the sliding member. The sliding member is sleeved on the guide column through the sliding hole and is in sliding fit with the guide column, so as to realize the sliding of the sliding member on the guide column. The guide column can be equal-diameter or unequal-diameter (for example, annular stepped).

[0046] Any existing technology that can be implemented can be used to drive the sliding member, such as electromagnetic drive devices, electric drive devices, or hydraulic drive devices. As a preferred embodiment, one-way hydraulic drive (from disengagement to engagement) and spring return (from engagement to disengagement) can be used. For example, an oil cavity for one-way drive is provided between the sliding hole wall of the sliding member and the peripheral surface (side surface) of the guide column. When the oil cavity is continuously filled with pressure liquid (such as hydraulic oil), the sliding member is pushed to move from the disengaged position to the engaged position. When the oil cavity releases (flows out) the pressure liquid, the sliding member moves from the engaged position to the disengaged position under the action of the return spring. Thus, as long as the injection or outflow of pressure liquid in the oil cavity is controlled, the corresponding movement of the sliding member can be realized, and the engagement or disengagement of the clutch-type coupling can be realized.

[0047] An opposite inner end face (annular end face of the annular shoulder / step structure) can be provided between the guide post and the sliding hole, and the spacing (space) between the inner end face of the guide post and the inner end face of the sliding hole wall forms an oil chamber 45 (see Figure 3 ). When the sliding member moves to the engagement position, the volume of the oil chamber is minimum (preferably not zero to facilitate buffering / damping), and when the sliding member moves to the disengagement position, the volume of the oil chamber is maximum. An oil supply channel can be provided in the first side member (including the guide post) for communicating the oil chamber.

[0048] The oil passage of the oil chamber can include an oil supply passage, an oil return passage, and a supplementary oil passage (see Figure 4 ). These oil passages can be provided according to the prior art. A hydraulic pump, a one-way valve, and a filter can be provided on the oil supply passage. An overflow valve and a coolant can be provided on the oil return passage. A supplementary oil pump and a one-way valve can be provided on the supplementary oil passage. An oil tank can be provided, into which the oil return flows, and from which the oil supply and the supplementary oil are extracted. Corresponding channels (e.g., by drilling, not shown) can be provided in the first side member for realizing the communication of the oil chamber with each oil passage (oil supply passage, oil return passage, supplementary oil passage). The outer ports of the channels are opened on the side surface of the first side member, and annular swivel joints are provided at the corresponding positions of the first side member. The annular swivel joints are in sealed sliding connection with the first side member (sealed sliding on both sides), and the annular inner ports thereof are always in communication with the corresponding channels in the first side member during rotation of the first side member, thereby allowing the external (outside the first side member) oil passages and the corresponding provided (e.g., pumps, valves) to be fixedly provided (e.g., mounted on respective foundations or fixed supports).

[0049] The sliding hole wall and the guide post on both sides of the oil chamber are in sealed sliding cooperation (maintaining sealed sliding on both sides throughout the entire stroke of the sliding member), thereby ensuring stable movement of the sliding member while maintaining the sealing of the oil chamber. The sliding hole wall and the guide post peripheral surface (or side surface) can be provided in the form of an annular step with different diameters to form the inner end face enclosing the oil chamber. The shapes and structures of the remaining areas of the sliding hole wall and the guide post peripheral surface can be provided according to actual needs. For example, an annular positioning groove can be provided on the sliding hole wall on the first side of the oil chamber, and a bidirectional limiting plate 43 (or positioning ring, annular) is provided on the guide post in the positioning groove. When the sliding member moves to the engagement position, the positioning ring contacts the second side end face of the positioning groove, preventing the sliding member from continuing to move to the first side, thereby forming the limiting (or positioning) of the sliding member at the engagement position. When the sliding member moves to the disengagement position, the positioning ring contacts the first side end face of the positioning groove, preventing the sliding member from continuing to move to the second side, thereby forming the limiting of the sliding member at the disengagement position.

[0050] Synchronous condensers can be connected to the power system using existing technology. Their main function is dynamic reactive power compensation, which maintains grid voltage stability and improves power quality by rapidly absorbing or releasing reactive power. A shaft system conducive to the stable operation of the synchronous condenser can be constructed, supporting the main shaft (rotor shaft) of the synchronous condenser through excitation-end bearings and non-excitation-end bearings, ensuring high-speed and stable rotor rotation, and providing a mechanical basis for reactive power regulation.

[0051] The shaft system needs to be adapted to the rapid response of the power grid conditions (e.g., when there is a sudden voltage change, the synchronous condenser needs to quickly adjust the reactive power output). Any suitable existing clutch coupling can be used to connect the flywheel shaft and the synchronous condenser shaft, so as to achieve flexible switching of the connection state with the flywheel. The "disengagement-engagement (coupling)" function of the clutch coupling can be used to adapt to the above requirements.

[0052] The core function of a flywheel is to store and release energy using its rotational inertia. When the power grid is stable, the synchronous condenser drives the flywheel to rotate and store mechanical energy; when the power grid fluctuates (such as voltage drops or frequency anomalies), the flywheel releases its inertia to assist the synchronous condenser in responding quickly and supporting the transient stability of the power grid.

[0053] "Linkage-decoupling" between flywheel and synchronous condenser: Under stable operating conditions, the synchronous condenser drives the flywheel to store energy through the engagement of the clutch coupling; when the power grid changes suddenly, if the synchronous condenser needs to respond quickly and independently (or the flywheel needs to release energy separately to assist), the coupling can be separated, and the synchronous condenser and flywheel can be decoupled and perform their respective functions.

[0054] Generally, the basic condition for a clutch-type coupling to allow engagement is that the speed difference between the synchronous condenser and the flywheel is within a safe range, that is:

[0055] ,

[0056] in: To adjust the absolute value of the speed difference between the camera and the flywheel. To adjust the camera speed, The flywheel speed, The set access speed difference threshold can be 1 r / min under normal operating conditions, and can be relaxed to 5 r / min during emergency frequency adjustment to ensure rapid linkage. When the actual speed difference is less than the access speed difference threshold, the flywheel can be connected to the synchronous condenser (clutch coupling engagement). Whether to connect depends on the actual operating conditions and the required adjustment method.

[0057] When the shaft vibration exceeds the limit (amplitude greater than the allowable shaft vibration threshold) or the speed difference is too large (greater than the set forced separation speed threshold), forced separation (clutch coupling disconnection) is triggered. Typically, the allowable shaft vibration threshold can be 8 mm / s, or it can be set based on the shaft fatigue strength. The forced separation speed threshold can be 3 r / min.

[0058] Generally, the state control of the clutch coupling can follow the principle of voltage priority. In the case of voltage emergency (for example, the absolute value of the difference between the actual voltage and the rated voltage is greater than a certain value), the independent reactive power regulation of the phase modifier is preferentially performed (cut off in conjunction with the flywheel), so as to avoid the flywheel inertia from dragging the response speed. The second principle is the frequency coordination principle. In the case of frequency fluctuation, the engagement is maintained, the flywheel inertia is used for fast response, the phase modifier is assisted for regulation, and the complementarity of “mechanical inertia + electrical regulation” is embodied. At the same time, a safety boundary should be set, and a limiting condition is included in all formulas to ensure that the equipment operates within the rated parameters and to avoid overloading or mechanical damage.

[0059] Generally, in the engaged state of the coupling, the flywheel shaft and the phase modifier shaft are fixedly connected, the mechanical torque channel between the two is connected, the phase modifier can drag the flywheel to store energy (the phase modifier drives the flywheel to rotate), or the flywheel releases inertia to assist the phase modifier (the flywheel torque is transmitted to the phase modifier); in the disengaged state of the coupling, the flywheel shaft and the phase modifier shaft are separated, the mechanical torque channel between the two is cut off, and the phase modifier and the flywheel rotate independently and do not transmit mechanical force to each other (the phase modifier can independently regulate reactive power, and the flywheel can independently release energy). This “either-or” state design ensures that the control logic is simple and reliable, without the need for complex intermediate state regulation, and meets the demand of the power grid for “fast response” (such as millisecond-level action in the case of voltage / frequency mutation).

[0060] The two ends of the phase modifier shaft are respectively installed through the excitation end bearing 1 and the non-excitation end bearing 3, and the other side of the flywheel shaft 11 is installed through the flywheel side bearing 7 and connected to the flywheel side generator (if provided) through the second clutch coupling, thereby ensuring stable rotation of the flywheel itself and enabling the flywheel side generator 8 to realize conversion of mechanical energy into electrical energy.

[0061] The flywheel protective cover 6 is used for safety protection of the flywheel and can be reasonably set according to the actual condition of the flywheel.

[0062] In the case of separation of the flywheel and the phase modifier, the phase modifier can independently respond to the reactive power demand of the power grid without being “dragged” by the flywheel inertia, so as to realize fast reactive power regulation (for example, in the case of sudden rise of the grid voltage, the phase modifier needs to instantaneously absorb reactive power, and after separation, the flywheel load does not hinder the response, so the response is more agile); the flywheel can independently participate in the inertia support of the power grid (for example, in the case of phase modifier failure, the coupling is separated, and the flywheel can release inertia to the power grid through the flywheel side generator to assist in maintaining the frequency stability.

[0063] In the case of disconnection of the clutch coupling and engagement of the second clutch coupling (if provided), the flywheel side generator is coupled (or connected, or engaged) with the flywheel, and the output 12 of the flywheel side generator (when working in the motor state, which can be used for input) is connected to the power grid through the flywheel side power conversion device (including the bidirectional converter 9 and the bidirectional inverter 10). In this case, the flywheel can directly respond to the demand of the power grid through the power conversion device. When the clutch coupling is disconnected, the phase modifier is still connected to the power grid according to the conventional setting mode, and the phase modifier function is independently realized.

[0064] The engagement and disconnection of the second clutch coupling can be controlled according to the working requirements of the flywheel.

[0065] The working state and working parameters of the flywheel side generator can be controlled according to the working requirements of the flywheel.

[0066] The following cooperative work can be realized through the clutch coupling (and the matching control if necessary) to strengthen the system capacity, for example:

[0067] In the flywheel energy storage stage, the phase modifier drives the flywheel to rotate, so that the flywheel efficiently stores the inertia. The two parts of the clutch coupling can be connected by a helical key, and a corresponding helical key groove is provided. Through the helical key connection, it is beneficial to ensure stable transmission of torque.

[0068] In the flywheel energy release stage, the power grid fluctuates, the flywheel releases the inertia, and the inertia is reversely transmitted to the phase modifier through the clutch coupling to assist the phase modifier to quickly output reactive power (for example, when the voltage drops, the flywheel inertia is converted into mechanical energy of the phase modifier, helping the phase modifier to increase the output of reactive power in a short time to support the recovery of the power grid voltage).

[0069] The linkage of the phase modifier and the flywheel makes the "electrical regulation" of the phase modifier combined with the "mechanical inertia" of the flywheel, so that the transient response speed of the power system and the voltage / frequency stability can be improved through the cooperation of the system to cope with complex working conditions such as new energy grid connection (such as wind power and photovoltaic fluctuation). The phase modulation system composed of the phase modifier and the flywheel device can realize "independent fast reactive power regulation + cooperative inertia support" dual mode to adapt to the diverse demands of the power grid; the flywheel can accurately switch between "energy storage - energy release" states relying on the linkage / decoupling of the clutch coupling and the phase modifier. The clutch coupling acts as an "intelligent switch + buffer" to ensure the safety of the shaft system while complementing the functions of the phase modifier and the flywheel to improve the stability and reliability of the power system, and solve the problems of reactive power balance and insufficient inertia of the power grid.

[0070] Explanation of intelligent control algorithm:

[0071] I) Overall architecture of the algorithm

[0072] The intelligent control algorithm adopts a "hierarchical and multi-objective coordination" architecture, which is divided into data preprocessing layer, state evaluation layer, decision control layer and execution feedback layer, to realize the closed-loop control of "monitoring data → state judgment → control instruction → execution feedback". The core goal is to dynamically adjust the engagement / disengagement state of the clutch coupling and the power output of the flywheel by real-time analysis of the grid and device state, to ensure the stability of the grid voltage and frequency, while maintaining the operation synchronization of the phase modifier and the flywheel.

[0073] II) Core module and algorithm logic

[0074] 1) Data preprocessing layer: used for preprocessing the raw data (or basic data) collected by the monitoring device in real time to calibrate and normalize the data, forming preprocessed data to provide a reliable data foundation for subsequent analysis.

[0075] 2) State evaluation layer: used to evaluate the grid stability and device operating state based on the preprocessed data, forming evaluation results to provide judgment basis for decision-making.

[0076] 3) Decision control layer: used to calculate the action instruction of the clutch coupling and the power output value of the flywheel based on the state evaluation results and the preset control target.

[0077] 4) Execution feedback layer: used to convert the output instruction of the decision layer into action signals of the execution mechanism (such as hydraulic control signal of the clutch coupling, excitation adjustment signal of the flywheel side generator), and real-time collect the device state information after execution (such as coupling position / state feedback information, flywheel power output value / flywheel side generator power value), to correct the next round of decision (next round of state evaluation).

[0078] III) Algorithm core model basis

[0079] Voltage-reactive power regulation model: based on the reactive power-voltage characteristics of synchronous motor, the reactive power output of the phase modifier has a linear relationship with the terminal voltage deviation (within small perturbation range), which reflects the dynamic relationship between flywheel speed change and power.

[0080] Multi-objective decision logic: based on the "voltage priority" principle of power system (voltage collapse risk is higher than frequency anomaly), combined with the device safety boundary (synchronous speed difference threshold), the rule base is used to realize fast decision-making, taking into account response speed and control accuracy.

[0081] IV) Characteristics of the algorithm

[0082] Real-time: using microsecond-level data sampling and millisecond-level decision-making cycle to adapt to fast grid fluctuation scenarios (such as transient response of voltage dip).

[0083] Synergy: The synchronous condenser and flywheel complement each other's functions, with the synchronous condenser taking the lead in reactive power regulation and the flywheel providing auxiliary power support. The state switching of the clutch coupling acts as a "switch" for functional synergy, maximizing the overall efficiency of the system.

[0084] The mechanism of independent power output from the flywheel in the separated state (separation of the synchronous condenser and flywheel): The core of independent power output from the flywheel side is achieved through the "mechanical energy to electrical energy conversion system" and the "DC bus transmission network". The specific path is as follows:

[0085] 1) Energy source: The flywheel stores energy in the form of kinetic energy (mechanical energy) from high-speed rotation (e.g., when the power grid is stable, the synchronous condenser drives the flywheel to accelerate and store mechanical energy).

[0086] 2) Energy conversion device: The flywheel side is equipped with a dedicated generator (for example, rigidly connected to the flywheel shaft system through a second clutch coupling, rotating synchronously with the flywheel) and a bidirectional power conversion device, such as a combination of a bidirectional converter (which may be a voltage source converter VSC) and a bidirectional inverter.

[0087] 3) Working process: The flywheel side achieves independent power output through the path of "flywheel (mechanical energy) → generator (AC) → converter (DC) → DC bus → inverter (AC) → power grid", without relying on the mechanical connection with the synchronous condenser (it can be triggered when the coupling is separated). For example, when electrical energy needs to be output, the flywheel drives the generator rotor to rotate (rotating at reduced speed), and its kinetic energy generates alternating current through electromagnetic induction (a primary conversion of mechanical energy to electrical energy); the output 12 (alternating current) of the generator on the flywheel side is rectified into direct current (AC→DC) by the bidirectional converter 9 and connected to the DC bus 13 (e.g., a DC 1000V DC bus) to complete the standardization and adaptation of electrical energy; the electrical energy on the DC bus can be inverted into alternating current (DC→AC) with the same frequency and phase as the AC grid by another transformer (bidirectional inverter) 10 and directly injected into the AC grid (e.g., the 10kV AC bus 14 connected to the synchronous condenser side) to achieve independent output of electrical energy to the grid (other required phases and / or frequencies can also be used according to actual control needs).

[0088] The state of the clutch coupling and the bidirectional adjustment capability of the flywheel can be clearly defined by the following logic, the core of which is "energy storage and standby in normal state, and bidirectional response achieved by dynamic switching".

[0089] 1) Under normal conditions, the default state of the clutch coupling is the engaged (connected) state.

[0090] The normal state refers to the stable grid parameters (voltage, frequency) within the allowed range (such as voltage fluctuation ≤ ± 3% rated value, frequency fluctuation ≤ ± 0.05 Hz), at which the clutch coupling is in the combined state by default. The reasons are as follows: (a) energy storage standby: in the combined state, the phase modifier can drag the flywheel to rotate at the rated speed (such as 3000 r / min), continuously store mechanical energy (flywheel energy storage coefficient S f Maintained at 60%~80%), reserve energy for sudden fluctuations (similar to "battery charging standby"); (b) cooperative inertia support: in the combined state, the rotational inertia of the flywheel is superimposed with the shaft system of the phase modifier, enhancing the overall inertia of the system. Even if there is a slight fluctuation in the grid (such as a small change in load), the inertia can be used to buffer and reduce the parameter fluctuation amplitude, reducing the adjustment frequency.

[0091] 2) Implementation logic of bidirectional regulation: "energy storage-energy release" bidirectional action in combined / separated states.

[0092] The "bidirectional problem" of the grid refers to the two directions of parameter deviation from the rated value (such as frequency too high / low, voltage surge / dip). The flywheel realizes bidirectional response through dynamic switching between "combined state cooperative regulation" and "separated state independent regulation". The specific implementation is as follows:

[0093] i) Adjustment logic for "low parameter" (such as frequency < 50 Hz, voltage dip)

[0094] In the combined state, the flywheel can release stored mechanical energy. The specific method can be: (a) when the frequency is low, the flywheel transmits torque to the phase modifier through the clutch coupling to assist the phase modifier in increasing active power (flywheel kinetic energy → mechanical torque → phase modifier active power output), quickly supporting the frequency rise; (b) when the voltage drops, the inertia support of the flywheel makes the shaft system of the phase modifier more stable, and the phase modifier can more accurately increase the reactive power (reduce the interference of speed fluctuation on reactive power output).

[0095] In the separated state, the flywheel can independently release energy. The specific method can be: (a) when the frequency is low, the flywheel rotates at a reduced speed, and the kinetic energy is converted into electrical energy by the generator (converted into alternating current by the inverter), directly injecting active power into the grid to make up for the active power shortage; (b) when the voltage drops, the flywheel side inverter can adjust the output voltage phase to indirectly provide reactive power support to the grid (assist the phase modifier to quickly restore the voltage).

[0096] ii) Adjustment logic for "high parameter" (such as frequency > 50 Hz, voltage surge)

[0097] In the combined state, the flywheel can absorb excess energy of the power grid. The specific way can be: (a) when the frequency is too high, the phase modifier drags the flywheel to accelerate rotation (power surplus of the power grid → mechanical power of the phase modifier → kinetic energy storage of the flywheel), reduces the active surplus of the power grid, and suppresses the frequency rise; (b) when the voltage rises suddenly, the flywheel inertia can stabilize the speed of the phase modifier (to avoid the deviation of reactive power regulation caused by sudden speed rise), and ensure accurate absorption of reactive power.

[0098] In the separated state, the flywheel can store energy independently. The specific way can be: (a) when the frequency is too high, the flywheel absorbs the active power of the power grid through the generator (AC → rectifier to DC → drive the flywheel to accelerate), converts the excess energy into kinetic energy storage, and reduces the frequency of the power grid; when the voltage rises suddenly, the phase modifier absorbs reactive power independently, and the flywheel side converter can pause energy release and switch to "absorb reactive power" mode (adjust through inverter, auxiliary relief voltage surge).

[0099] 3) Core logic: the essence of "two-way regulation" is the reversibility of "energy storage and release" of the flywheel.

[0100] The core feature of the flywheel is the bidirectional conversion of kinetic energy and electrical energy (mechanical energy ↔ electrical energy): when the power grid needs to "supplement energy" (parameters are too low), the flywheel changes from "energy storage state" to "energy release state" (kinetic energy → electrical energy); when the power grid needs to "consume excess energy" (parameters are too high), the flywheel changes from "energy release state" to "energy storage state" (electrical energy → kinetic energy).

[0101] The "combination / separation" of the clutch coupling only determines the energy transmission path (mechanical linkage or electrical independence), and does not affect the bidirectional conversion capability of the flywheel itself. The combination in the normal state is to "reserve the energy basis for two-way regulation", to ensure that the flywheel can quickly switch the action direction when the power grid appears any direction fluctuation, and cooperate with the phase modifier to realize comprehensive regulation.

[0102] The control system of the phase modifier and the flywheel cooperates through real-time monitoring of the power grid state (voltage, frequency) and device parameters (speed, vibration, etc.), and realizes the dynamic cooperation of the two according to the preset quantitative formula. The core goal is: under the premise of ensuring the safety of the equipment, quickly respond to the voltage / frequency fluctuation of the power grid, and improve the stability of the power grid through the mode of "reactive power leading of the phase modifier + active power assistance of the flywheel". The system control logic covers four scenes of normal energy storage, voltage regulation, frequency regulation, and abnormal protection, forming a closed-loop control system.

[0103] Core control signals and parameters:

[0104] 1) Input signal

[0105] Power grid state signal: measured voltage U 实测 (kV), real-time frequency fFrequency deviation Δf=|f-50| (Hz), or, without loss of generality, Δf=|f-grid rated frequency| (Hz); U 额定 ;

[0106] Device status signal: phase modifier rotational speed n g (r / min), current flywheel rotational speed n f (r / min), shaft system vibration value (mm / s);

[0107] Device parameter: phase modifier rated capacity S N (Mvar), flywheel rated power P fN (MW), flywheel maximum rotational speed n fmax (r / min), current flywheel rotational speed n f (r / min), phase modifier rated active capacity P gN (MW), flywheel moment of inertia J (kg·m 2 ), flywheel energy storage coefficient S f (or denoted as S_f).

[0108] 2) Core calculation parameters

[0109] Voltage deviation coefficient Δ U = ( U 额定 - U 实测 ) / V U 额定 ;

[0110] Frequency deviation Δf=|f-50| (Hz), or, without loss of generality, Δf=|f-grid rated frequency| (Hz);

[0111] Flywheel energy storage coefficient S f = ( n f / J n fmax ) 2 ;

[0112] Rotational speed difference Δ n = |ω n g - ω n f | (r / min).

[0113] Scenario-based control strategy:

[0114] One> Normal control mode (grid stable state)

[0115] 1) Trigger condition (any condition met triggers)

[0116] i) Voltage deviation: |ΔV| ≤ 5% (voltage within 97%~107% of rated value, adjustable); U

[0117] ii) Frequency deviation: Δf ≤ 0.2 Hz (frequency within 49.8~50.2 Hz, adjustable);

[0118] iii) Flywheel energy storage: S f <0.9 (not reach full energy storage state).

[0119] 2) Control target

[0120] i) Maintain grid voltage and frequency within normal range;

[0121] ii) Flywheel energy storage to full capacity (≥0.9), reserve energy for subsequent regulation; S f

[0122] iii) Specific actions:

[0123] Clutch coupling: keep engaged (satisfy Δn ≤ 1 r / min, normal operating condition engagement condition); n

[0124] Phase modifier: execute energy charging instructions, drag flywheel to accelerate energy storage;

[0125] Wherein, the energy charging power is calculated as follows:

[0126] ,

[0127] Wherein, the acceleration is controlled at 50~100 r / min / s (to avoid shaft impact). In calculation, the mechanical loss is usually 5%~10% of flywheel rated power, which can be determined based on experimental data or experience, and other coefficients can also be determined based on experimental data or experience. Since the flywheel and phase modifier are strictly synchronous in engagement state ( = , phase modifier speed), the core of energy charging power regulation is the precise control of flywheel angular acceleration .

[0128] Flywheel: no regulation output, synchronous rotation with phase modifier, speed gradually increases to n fmax . ​​​

[0129] Charging power regulation core means: relying on the control system's ability to regulate the excitation current of the phase modifier, realize dynamic matching of charging power - when the calculated charging power is high, increase the excitation current of the phase modifier, increase the active output of the phase modifier, and promote the angular acceleration of the flywheel , meet the high power charging demand; when the calculated charging power is low, reduce the excitation current of the phase modifier, reduce the active output of the phase modifier, and reduce the angular acceleration of the flywheel , avoid overcharging. Thus, the flywheel speed can also be controlled within a certain value or range, so that the flywheel realizes corresponding energy storage.

[0130] Closed-loop feedback control mechanism: real-time acquisition of flywheel speed by speed sensor 实际 , calculate the actual angular acceleration n ; compare the actual charging power with the calculated charging power, if the deviation is > 5%, adjust the excitation current of the phase modifier immediately; at the same time, monitor the speed difference Δ and shaft vibration value, trigger the safety boundary to immediately suspend power adjustment, and prioritize equipment operation safety.

[0131]

[0132] · When S f ＜ 0.6 (low energy storage state): calculate high charging power, control flywheel angular acceleration at 80~100 r / min / s, quickly increase flywheel speed, and shorten energy storage period;

[0133] · When 0.6≤ S f ＜ 0.9 (medium energy storage state): reduce the calculated charging power, control the flywheel angular acceleration at 50~80 r / min / s, gently charge, and avoid sudden speed rise;

[0134] · When S f ≥ 0.9 (high energy storage state): make the calculated charging power approximately equal to the mechanical loss , flywheel angular acceleration ≈ 0, phase modifier only outputs a small amount of active to offset losses, and maintains flywheel speed stable (i.e. flywheel standby state).

[0135] 3) Exit conditions

[0136] i) Flywheel energy storage coefficient Sf ≥ 0.9 (close to full energy storage);

[0137] ii) Phase modifier stops charging, goes into no-load operation (only basic reactive output, reactive output Q g ≈0).

[0138] Two> Voltage regulation mode (grid voltage abnormality)

[0139] 1) State determination

[0140] Voltage state Trigger condition Priority Voltage emergency state | Δ | > 10% Highest Voltage warning state 5% < |Δ| < 10% Medium Voltage normal state | Δ | < 5% Exit

[0141] 2) Control target

[0142] i) Voltage emergency state: ∣Δ U ∣ is reduced to within 10% within 10 seconds, and is restored to within 5% within 30 seconds;

[0143] ii) Voltage early warning state: ∣Δ U ∣ is reduced to within 5% within 60 seconds.

[0144] 3) Specific actions:

[0145] i) Voltage emergency state (∣ΔU∣> 10%)

[0146] Clutch coupling: forced separation (based on voltage priority logic, to avoid flywheel inertia dragging response speed);

[0147] Phase modifier: calculate (output) reactive output: .

[0148] Coefficient setting: =1.0~1.2 (high gain fast regulation); >0 (voltage drop) to increase reactive power, <0 (voltage surge) to absorb reactive power.

[0149] Limiting condition: ∈[-1.2S N ,1.2S N ] (to avoid overexcitation / underexcitation damage)

[0150] Flywheel (only participates in voltage drop): output auxiliary support power .

[0151] .

[0152] Coefficient setting: =0.7~0.8 (strengthen support).

[0153] Limiting condition: (To prevent energy storage from being depleted).

[0154] ii) Voltage warning status (5% < |ΔU| ≤ 10%)

[0155] Clutch coupling: maintains engagement (Δ) n ≤1 r / min);

[0156] Adjusting the camera: Same as in an emergency, but... =0.8~1.0 (adjust gradually to avoid overshoot);

[0157] Flywheel: Does not participate in adjustment (can be restored by adjusting the camera independently).

[0158] 4) Exit and Resume

[0159] Exit condition: |Δ U |≤5% and stable for 30 seconds.

[0160] Recovery action: The coupling re-engages (must meet Δ) n ≤1 r / min), if flywheel energy storage S f If the value is less than 0.5, activate the camera's charging mode until... ≥0.8.

[0161] 3. Frequency Regulation Mode (Power Grid Frequency Anomaly)

[0162] 1) State judgment

[0163] Frequency state Trigger condition Regulation direction Frequency severe deviation Δ > 0.5 Hz Emergency strong support Frequency slight deviation 0.2 Hz < Δ ≤ 0.5 Hz Regular coordinated regulation Frequency normal state Δ < 0.2 Hz Exit

[0164] 2) Control objectives

[0165] i) Severe frequency deviation: Within 5 seconds, Δ f Reduced to below 0.3Hz, and to below 0.1Hz within 15 seconds;

[0166] ii) Slight frequency deviation: within 30 seconds, Δ f Reduced to below 0.1Hz.

[0167] 3) Specific actions

[0168] Clutch coupling: Maintains engagement (Δ allowed during emergency frequency adjustment) n ≤5 r / min, priority should be given to ensuring linkage);

[0169] Flywheel (main regulator): Calculates (output) frequency to support power. :

[0170] .

[0171] Coefficient setting: When the frequency is low ( f<49.8 Hz): =+1 (energy release); =0.002~0.003MW·min / r; when the frequency is too high ( f >50.2 Hz): =−1 (energy absorption); =0.001~0.002 MW·min / r.

[0172] Restrictions: (Do not exceed rated power).

[0173] Camera adjustment (auxiliary adjustment): Output auxiliary power: .

[0174] Coefficient settings: =0.3~0.4 (limits the active power output ratio, does not affect reactive power output), and the direction is consistent with the flywheel (low frequency outputs positive active power, high frequency outputs negative active power).

[0175] 4) Exit and Resume

[0176] i) Exit condition: Δ f ≤0.1 Hz and stable for 30 seconds;

[0177] ii) Recovery action:

[0178] The flywheel power returns to 0, the active power output of the synchronous condenser is reset to zero (restoring reactive power regulation function), if the flywheel stores energy S f <0.6 (after energy release) or S f >0.95 (after energy absorption), after energy release, adjust the camera to charge to S f ≥0.8, after energy absorption, the flywheel naturally decelerates (or the camera is adjusted and dragged in the opposite direction) to... S f ≤0.9.

[0179] IV. Anomaly Protection Mode (Device Safety Trigger)

[0180] 1) Triggering conditions:

[0181] i) Shaft vibration value > 8 mm / s (exceeds fatigue strength threshold);

[0182] ii) Speed ​​difference Δn > 3 r / min (abnormal overspeed difference after meshing);

[0183] iii) Equipment operating beyond rated parameters (e.g., reactive power of synchronous condenser > 1.2 seconds) N Flywheel power > P fN ).

[0184] 2) Control target

[0185] i) Immediately cut off the dangerous linkage to prevent equipment damage;

[0186] ii) Maintain the stability of the power grid foundation (the phase modifier retains the minimum reactive power output).

[0187] 3) Specific actions

[0188] i) Clutch coupling: immediately forced separation;

[0189] ii) Phase modifier: switch to independent operation mode, reactive power output limited to [-0.5S N ,0.5S N ] (only maintain basic voltage);

[0190] iii) Flywheel: enter free deceleration state (only affected by mechanical loss), speed drops to n f ≤0.5n fmax (safety range);

[0191] iv) Alarm output: trigger audible and visual alarms, upload abnormal signals to the monitoring system.

[0192] 4) Recovery conditions

[0193] i) Vibration value ≤5 mm / s (stable for more than 30 seconds);

[0194] ii) Speed difference Δn ≤1 r / min;

[0195] iii) All equipment parameters return to the rated range;

[0196] iv) After manual confirmation, the coupling re-engages and the system restarts normal control.

[0197] Control logic priority and coordination relationship:

[0198] 1) Priority order: abnormal protection mode > voltage emergency state > frequency serious deviation > voltage warning state > frequency slight deviation > normal control;

[0199] 2) Coordination principles:

[0200] i) When voltage and frequency are abnormal at the same time, the voltage emergency state is prioritized (voltage collapse is more directly harmful to the power grid);

[0201] ii) In normal state, the flywheel energy storage is the core, and in dynamic adjustment, the mode is "flywheel fast response + phase modifier continuous support";

[0202] iii) all the regulation actions are limited by the safety boundary of the device (such as power, speed, vibration threshold), forming a closed loop of "target calculation - boundary check - instruction output".

[0203] The setting of the above various parameters (for example, threshold values) can be specifically set according to actual needs or the overall control strategy and supporting of the system, and can be the same as or different from the above examples.

[0204] If necessary, other suitable modes of regulation can be performed according to the prior art and control target requirements for specific situations.

[0205] Engineering application:

[0206] 1) Parameter setting: the coefficients (K U , K f , etc.) need to be adjusted according to the characteristics of the power grid (such as voltage sensitivity, frequency inertia) on site, and it is recommended to take the intermediate value of the relevant coefficients (such as K U =1.0, K f =0.002) initially, and then optimized through trial operation.

[0207] 2) Response time: the sampling frequency of the system design is 100Hz (the state is updated once every 10ms), ensuring that the voltage regulation response time is ≤50ms and the frequency regulation response time is ≤20ms.

[0208] 3) Maintenance requirements: regularly check the accuracy of the sensors (especially voltage, speed, and vibration signals), test the coupling disengagement / engagement function every quarter, and ensure reliable action in emergency situations.

[0209] The various preferred and optional technical means disclosed in the present application can be arbitrarily combined, forming several different specific embodiments, except for the specific description and the further limitation of one preferred or optional technical means as another technical means.

Claims

1. A device for increasing the moment of inertia of a new energy phase modifier combined with a flywheel, provided with a phase modifier, characterized in that The flywheel is connected to the main shaft of the phase modifier through a clutch type coupling, and the engagement or separation of the flywheel and the rotating shaft of the phase modifier is controlled through the clutch state of the clutch type coupling. The outer side of the flywheel is connected with a flywheel side generator, and the output of the flywheel side generator is connected to the power grid through a flywheel side transformer device. The flywheel side transformer device is a bidirectional transformer device. The connection mode between the outer side of the flywheel and the flywheel side generator is that the flywheel shaft is connected to the input shaft of the flywheel side generator through a second clutch type coupling. The control system controls the clutch state of the clutch type coupling to realize the engagement or separation between the flywheel and the phase modifier. The control system controls the clutch state of the second clutch type coupling to realize the engagement or separation between the flywheel and the flywheel side generator. The control system controls the excitation current connected to the phase modifier to control the working state of the phase modifier. The control system controls the control parameters or working mode of the flywheel side transformer device to control the working state of the flywheel side generator. In the disconnected state of the clutch type coupling, the phase modifier and the flywheel work independently, the phase modifier can independently implement reactive power regulation, the flywheel independently releases energy to the power grid or does not release energy to the power grid. The clutch type coupling includes a first side member, a second side member and a sliding member arranged coaxially. The sliding member is located between the first side member and the second side member. The sliding member connection sides of the first side member and the second side member are respectively provided with a first side internal spline and a second side internal spline. The two sides of the sliding member are respectively provided with a corresponding first side external spline and a second side external spline. Within the stroke range of the sliding member, the first side external spline always remains in spline connection with the first side internal spline, and the second side external spline and the second side internal spline are engaged with each other when the sliding member is in the engagement position, and are separated from each other when the sliding member is in the separation position. The first side external spline and the first side internal spline are straight splines, and the second side external spline and the second side internal spline are threaded splines. The first side member is provided with a guide column, and the sliding member is sleeved on the guide column through an axial sliding hole. An oil cavity is arranged between the sliding hole and the guide column, and the sliding hole and the guide column are sealingly and slidingly connected on both sides of the oil cavity. The oil cavity is connected with an oil supply pipeline and an oil return pipeline. A return spring is arranged between the first side member and the sliding member, and / or a return spring is arranged between the second side member and the sliding member. When the clutch type coupling is switched, the sliding member is pushed to the engagement position by the high-pressure liquid pressure injected into the oil cavity, and the sliding member is pushed to the separation position by the return spring.

2. The apparatus of claim 1, wherein A control system is arranged for controlling the cooperative work of the parts. The control system analyzes and judges the real-time working state according to the real-time obtained related basic data, and controls according to the real-time working state and the set control target and control mode.

3. The method for improving the moment of inertia of a new energy phase modifier combined with a flywheel, characterized in that The new energy phase modifier combined with the flywheel inertia increasing device of any one of claims 1-2 is used to implement power system regulation. The engagement or separation of the flywheel and the phase modifier is realized by switching the state of the clutch type coupling.

4. The method of claim 3, wherein Normal control mode, voltage regulation mode, frequency regulation mode and abnormal protection mode are provided. When the power grid is in normal state, the normal control mode is adopted, the clutch type coupling is engaged, the phase modifier drags the flywheel to accelerate and store energy; when the voltage of the power grid is abnormal, the voltage regulation mode is adopted, the clutch type coupling is disconnected, the phase modifier outputs reactive power according to the regulation requirement; when the frequency of the power grid is abnormal, the frequency regulation mode is adopted, the clutch type coupling is engaged, when the actual frequency is lower than the rated frequency of the power grid, the flywheel side generator works in the generator state, the flywheel releases energy to the power grid, when the actual frequency is higher than the rated frequency of the power grid, the flywheel absorbs energy, the flywheel side generator works in the motor state, and the flywheel absorbs energy from the power grid; when the abnormal protection is triggered, the abnormal protection mode is adopted, an alarm signal is output, the clutch type coupling is disconnected, the phase modifier operates independently, the reactive power output of the phase modifier is limited to the level of maintaining the basic voltage, and the flywheel enters the free deceleration state until the rotating speed is reduced to the safety range.

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