Composite gravity energy storage system and control method thereof

Abstract

The application discloses a composite gravity energy storage system and a control method thereof, which comprises a gravity energy storage device and a power type energy storage module, wherein the gravity energy storage device is used for absorbing redundant electric energy of a power grid or releasing electric energy when the electric energy of the power grid is insufficient; and the power type energy storage module is used for compensating for the fluctuation of active power in the working process of the gravity energy storage device or providing millisecond-level and above fast power compensation to the power grid. Through implementation of the application, the advantages of the gravity energy storage technology and the power type energy storage technology are combined, the problems of output power fluctuation and incapability of millisecond-level and above response of the gravity energy storage technology are overcome, and the safe and stable operation of the power grid is facilitated. The application has the advantages of large energy storage capacity, low cost, fast output power response, small fluctuation, high safety, high cycle efficiency, no environmental pollution, small geographical condition limitation and the like, has obvious superiority compared with other single type energy storage technologies, can be applied to distributed and scaled applications, and has wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, specifically to a composite gravity energy storage system and its control method. Background Technology

[0002] To combat global warming, vigorously developing renewable energy and achieving a clean energy transformation has become a major trend in the energy sector. However, the randomness and volatility of wind and solar power generation mean that large-scale integration of renewable energy sources can negatively impact grid stability. Therefore, to support the rapid development of renewable energy, the development of mature and reliable large-scale energy storage technologies has become an urgent need.

[0003] In recent years, various energy storage technologies have flourished, with pumped hydro storage being the most mature, accounting for approximately 90% of the world's current installed energy storage capacity. However, pumped hydro storage is severely constrained by geographical conditions, thus limiting its development potential. Gravitational potential energy storage is a novel mechanical energy storage technology with advantages such as large storage capacity, less susceptibility to geographical limitations, and low cost, making it an important direction for the future development of large-scale mechanical energy storage.

[0004] Both gravity energy storage and pumped hydro storage achieve large-scale energy storage through the conversion between electrical energy and gravitational potential energy. Pumped hydro storage uses water as its storage medium, and the continuous flow of water drives a turbine to achieve stable power output. Gravity energy storage, on the other hand, uses modular, discrete weights as its storage medium. The continuous loading and unloading of these weights causes repeated start-stop cycles of the motor, resulting in significant energy losses and noticeable fluctuations in output power. This reduces the cyclic efficiency of the gravity energy storage system and is detrimental to the stable operation of the power grid. Summary of the Invention

[0005] In view of this, embodiments of the present invention provide a composite gravity energy storage system and its control method to solve the technical problem in the prior art that repeated starting and stopping of the motor in gravity energy storage technology easily causes a large amount of loss and also leads to obvious fluctuations in output power.

[0006] The technical solution proposed in this invention is as follows:

[0007] The first aspect of this invention provides a composite gravity energy storage system, comprising: a gravity energy storage device and a power-type energy storage module. The gravity energy storage device is used to absorb excess electrical energy from the power grid or to release electrical energy when the power grid is insufficient. The power-type energy storage module is used to compensate for fluctuations in active power during the operation of the gravity energy storage device or to provide millisecond-level or higher rapid power compensation to the power grid.

[0008] Optionally, the power-type energy storage module is specifically used to generate power to compensate for the shortfall in power when the fluctuation of gravity energy storage or grid active power is positive; and to absorb power to compensate for the excess power when the fluctuation of gravity energy storage or grid active power is negative.

[0009] Optionally, the gravity energy storage device includes: a gravity energy storage module, a motor module, and a power electronic converter module. The motor module is connected to the gravity energy storage module and is used to control the movement of the gravity energy storage module to absorb or release electrical energy. One end of the power electronic converter module is connected to the power grid, and the other end is connected to the motor module, and it is used to control the motor module.

[0010] Optionally, the gravity energy storage module includes: a mass module, a mass traction module, and a support module; the support module is a natural terrain or man-made structure with a height difference, used to provide the height difference required for the movement of the mass module and to provide support for the mass module; the mass traction module is used to traction the mass module to move upward or downward under the control of the motor module; the mass module is used to convert electrical energy into gravitational potential energy for storage or to convert gravitational potential energy into electrical energy for release.

[0011] Optionally, the power-type energy storage module is connected to the gravity energy storage device through the power electronic converter module, and the power-type energy storage module is specifically used to compensate for the fluctuation of active power during the start-up and braking phases of the motor module.

[0012] Optionally, the power-type energy storage module is connected to the DC side of the power electronic converter module; or, the power-type energy storage module is connected to the AC rectifier side of the power electronic converter module; or, the power-type energy storage module is connected to the AC inverter side of the power electronic converter module.

[0013] Optionally, the power-type energy storage module includes any one of supercapacitors, batteries, or flywheel energy storage; or, when the composite gravity energy storage system is connected to a high-voltage, high-capacity scenario of 10kV or above, the power electronic converter module adopts a cascaded full-bridge or modular multilevel topology, and the power-type energy storage module is the DC support capacitor in the power electronic converter module.

[0014] Optionally, the composite gravity energy storage system further includes: a control system, which controls the motor module through the power electronic converter module according to the operating status of the power grid; determines the configuration capacity of the power-type energy storage module according to the fluctuation of the active power, and controls the power-type energy storage module to perform compensation through the power electronic converter module.

[0015] Optionally, during a single operation of the composite gravity energy storage system, the capacity of the power-type energy storage module is configured using a first configuration capacity, a second configuration capacity, or a third configuration capacity, depending on the compensation strategy of the power-type energy storage module in the composite gravity energy storage system: When the power-type energy storage module is controlled using a gravity potential energy conversion power compensation strategy, the capacity of the power-type energy storage module is configured using the first configuration capacity, which is calculated based on the mass of the mass module, the speed of the mass module, and the efficiency of the motor module; When the power-type energy storage module is controlled using a trapezoidal compensation strategy, the capacity of the power-type energy storage module is configured using the second configuration capacity, which is calculated based on the first configuration capacity, the speed and acceleration of the mass module during the startup phase, and the energy absorbed; When the power-type energy storage module is controlled using a rectangular compensation strategy, the capacity of the power-type energy storage module is configured using the third configuration capacity, which is calculated based on the first configuration capacity, the efficiency of the motor module, the speed of the mass module, and the acceleration of the mass module during the startup phase.

[0016] Optionally, when the composite gravity energy storage system is running stably and continuously, the power-type energy storage module is also used to discharge during the upward movement of the mass module and charge during the reset of the mass traction module; and to charge during the downward movement of the mass module and discharge during the reset of the mass traction module.

[0017] Optionally, when the composite gravity energy storage system is running stably and continuously, the charging energy or discharging energy of the power-type energy storage module is determined based on the ratio of the integral of the exchange power to the operating cycle. The configuration capacity of the power-type energy storage module is configured according to the technical and economic advantages of the charging energy or discharging energy in one cycle compared with the first configuration capacity, the second configuration capacity, or the third configuration capacity, in conjunction with the compensation strategy adopted for a single operation.

[0018] A second aspect of this invention provides a control method for a composite gravity energy storage system, comprising: acquiring the operating status of the power grid or receiving a dispatch command from the power grid; controlling the gravity energy storage device to convert excess electrical energy from the power grid into gravitational potential energy or to convert gravitational potential energy into electrical energy and release it back to the power grid when the power grid is insufficient, based on the operating status of the power grid or the dispatch command from the power grid; and controlling a power-type energy storage module to compensate for fluctuations in active power during the operation of the gravity energy storage device or to provide millisecond-level or higher rapid power compensation to the power grid.

[0019] Optionally, the control method of the composite gravity energy storage system further includes: when the composite gravity energy storage system operates once, configuring the capacity of the power-type energy storage module according to a first configuration capacity, a second configuration capacity, or a third configuration capacity based on different compensation strategies of the power-type energy storage module; wherein, when the power-type energy storage module is controlled using a gravity potential energy conversion power compensation strategy, the capacity of the power-type energy storage module is configured using the first configuration capacity, which is calculated based on the mass of the mass module, the speed of the mass module, and the efficiency of the motor module; when the power-type energy storage module is controlled using a trapezoidal compensation strategy, the capacity of the power-type energy storage module is configured using the second configuration capacity, which is calculated based on the first configuration capacity, the speed and acceleration of the mass module during the startup phase, and the energy absorbed; when the power-type energy storage module is controlled using a rectangular compensation strategy, the capacity of the power-type energy storage module is configured using the third configuration capacity, which is calculated based on the first configuration capacity, the efficiency of the motor module, the speed of the mass module, and the acceleration of the mass module during the startup phase.

[0020] Optionally, the control method of the composite gravity energy storage system further includes: when the composite gravity energy storage system is running stably and continuously, controlling the power type energy storage module to discharge during the upward movement of the mass module and charge during the reset of the mass traction module; charging during the downward movement of the mass module and discharging during the reset of the mass traction module.

[0021] Optionally, the control method of the composite gravity energy storage system further includes: when the composite gravity energy storage system is running stably and continuously, determining the charging energy or discharging energy of the power-type energy storage module based on the ratio of the integral of the exchange power to the operating cycle; and configuring the configuration capacity of the power-type energy storage module according to the technical and economic advantages of the charging energy or discharging energy in one cycle compared with the first configuration capacity, the second configuration capacity, or the third configuration capacity, in conjunction with the compensation strategy adopted for a single operation.

[0022] The technical solution provided by this invention has the following effects:

[0023] The composite gravity energy storage system and its control method provided in this invention combine the advantages of both gravity energy storage technology and power-type energy storage technology, overcoming the problems of output power fluctuation and inability to achieve millisecond-level or higher response in gravity energy storage technology, thus contributing to the safe and stable operation of the power grid. It achieves safe and reliable large-scale energy storage while effectively meeting the needs of stable operation of the power grid or load and efficient power conversion.

[0024] The composite gravity energy storage system provided in this invention utilizes a power-type energy storage module to provide an energy buffer during the start-up and shutdown process of the motor module. This improves the cycle efficiency of the gravity energy storage system, extends the service life of the motor, and significantly enhances resource utilization and the overall benefits of the system. The composite gravity energy storage system proposed in this invention has advantages such as large energy storage capacity, low cost, high safety, high cycle efficiency, no environmental pollution, and minimal geographical limitations. Compared to other single-type energy storage technologies, it has significant advantages, can adapt to distributed and large-scale applications, and possesses broad application prospects. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a structural block diagram of a composite gravity energy storage system according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the charging principle of a composite gravity energy storage system according to an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the discharge principle of a composite gravity energy storage system according to an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the principle of energy storage access to the DC side in a composite gravity energy storage system according to an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of the energy storage access mechanism side in a composite gravity energy storage system according to an embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of the energy storage access network side principle in a composite gravity energy storage system according to an embodiment of the present invention;

[0032] Figure 7(a) is a schematic diagram of the grid-side power before and after compensation according to an embodiment of the present invention; Figure 7(b) is a schematic diagram of the exchange power of the power-type energy storage module according to an embodiment of the present invention; Figure 7(c) is a schematic diagram of the exchange power of the gravity energy storage device according to an embodiment of the present invention; Figure 7(d) is a schematic diagram of the exchange power of the composite gravity energy storage system according to an embodiment of the present invention.

[0033] Figure 8(a) is a schematic diagram of the actual uplink switching power curve after compensation based on stable continuous operation switching power according to an embodiment of the present invention; Figure 8(b) is a schematic diagram of the actual downlink switching power curve after compensation based on stable continuous operation switching power according to an embodiment of the present invention; Figure 8(c) is a schematic diagram of the switching power curve based on gravitational potential energy compensation after compensation based on stable continuous operation switching power according to an embodiment of the present invention; Figure 8(d) is a schematic diagram of the switching power based on trapezoidal compensation after compensation based on stable continuous operation switching power according to an embodiment of the present invention; Figure 8(e) is a schematic diagram of the switching power based on rectangular compensation after compensation based on stable continuous operation switching power according to an embodiment of the present invention; Figure 8(f) is a schematic diagram of the switching power after compensation based on stable continuous operation switching power according to an embodiment of the present invention.

[0034] Figure 9 This is a schematic diagram of the upward waveform of conventional speed detection control according to an embodiment of the present invention;

[0035] Figure 10 This is a schematic diagram of the downlink waveform of the mass module in a composite gravity energy storage system according to an embodiment of the present invention;

[0036] Figure 11 This is a schematic diagram of the uplink waveform of the mass module in a composite gravity energy storage system according to an embodiment of the present invention;

[0037] Figure 12 This is a schematic diagram of the changes in energy storage and power of a composite gravity energy storage system according to an embodiment of the present invention;

[0038] Figure 13(a) is a schematic diagram of the uplink switching power variation of the composite gravity energy storage system based on the gravity potential energy conversion power compensation method according to an embodiment of the present invention, and Figure 13(b) is a schematic diagram of the downlink switching power variation of the composite gravity energy storage system based on the gravity potential energy conversion power compensation method according to an embodiment of the present invention.

[0039] Figure 14 A schematic diagram of the system exchange power variation of a composite gravity energy storage system based on a trapezoidal compensation method according to an embodiment of the present invention;

[0040] Figure 15 A schematic diagram of the system exchange power variation of a composite gravity energy storage system based on a rectangular compensation method according to an embodiment of the present invention. Detailed Implementation

[0041] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0042] The terms "first," "second," "third," "fourth," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0043] In the description of the invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0045] This invention provides a composite gravity energy storage system, such as... Figure 1 As shown, it includes: a gravity energy storage device 100 and a power-type energy storage module 1. The gravity energy storage device 100 is used to absorb excess electrical energy from the power grid or release electrical energy when the power grid is insufficient. The power-type energy storage module 1 is used to compensate for the fluctuation of active power during the operation of the gravity energy storage device or to provide the power grid with millisecond-level or higher rapid power compensation.

[0046] The composite gravity energy storage system provided in this invention combines the advantages of both gravity energy storage technology and power-type energy storage technology, overcoming the problems of output power fluctuation and the inability to achieve millisecond-level or higher response times in gravity energy storage technology. This is beneficial to the safe and stable operation of the power grid. It achieves safe and reliable large-scale energy storage while effectively meeting the needs of stable operation of the power grid or load and efficient power conversion.

[0047] In one implementation, such as Figure 2 and Figure 3 As shown, the gravity energy storage device 100 includes: a gravity energy storage module, a motor module 101, and a power electronic converter module 102. The motor module 101 is connected to the gravity energy storage module and is used to control the movement of the gravity energy storage module to absorb or release electrical energy. One end of the power electronic converter module 102 is connected to the power grid, and the other end is connected to the motor module 101, used to control the motor module 101. The motor module 101 can be composed of several regenerative braking motors; through the coordinated switching of these motors, the output power pulsation can be effectively reduced. The gravity energy storage module includes: a mass module 103, a mass traction module 104, and a support module 105 (not shown); the support module 105 is a natural terrain or man-made structure with a height difference, used to provide the height difference required for the movement of the mass module 103 and to provide support for the mass module 103; the mass traction module 104 is used to traction the mass module 103 to move upward or downward under the control of the motor module 101; the mass module 103 is used to convert electrical energy into gravitational potential energy for storage or to convert gravitational potential energy into electrical energy for release.

[0048] Specifically, the charging and discharging schematic diagram of this composite gravity energy storage system is as follows: Figure 2 and Figure 3 As shown, when there is excess electrical energy in the power grid, the gravity energy storage device absorbs the excess electrical energy and drives the motor module to lift the mass module through the mass traction module, converting the consumed electrical energy into gravity energy storage; when there is insufficient electrical energy in the power grid, the drive motor module releases the mass module, and the mass module drags the motor module to generate electricity, converting the gravitational potential energy of the mass module into electrical energy and feeding it back to the power grid.

[0049] The support module can be either natural terrain with a certain height difference, such as hills, valleys, and cliffs, or man-made structures that provide a certain height difference, such as shafts or artificial support structures. To provide support after the mass module moves up or down, the support module includes at least two stacking platforms at different elevations. For example, when two stacking platforms are included, the higher-elevation platform is the upper stacking platform, and the lower-elevation platform is the lower stacking platform. Although the support module can utilize either natural terrain or a constructed system, when the capacity of the gravity energy storage device reaches GWh or above, using natural terrain for the support module can effectively reduce costs and provide more reliable support for the mass module. Furthermore, using natural terrain makes it easier to create a height difference of hundreds of meters or more between the stacking platforms at different elevations.

[0050] The mass module can be composed of modular heavy blocks with a certain mass, or it can be composed of a modular container and the heavy object it carries. For example, the mass module can be composed of mass blocks made of relatively low-cost but relatively high-density materials such as concrete, iron blocks, or gravel. When concrete or iron ore is used, it can be made into independent mass blocks to form the mass module; when gravel is used, it can be loaded into a container to form the mass block. A mass module can contain one or more mass blocks, preferably multiple mass blocks, which is more conducive to balancing the output power. When forming the mass module, it is constructed as a modular cuboid or hexagonal prism structure for close stacking. The weight of the mass blocks in the mass module, taking into account the mechanical strength of other structures, should preferably be between 0.1 tons and 1000 tons; in practical applications, it can be determined according to specific actual needs.

[0051] like Figure 4 As shown, the mass traction module 104 comprises a pulley system, a rope, a gearbox, and a fixing component 2. The rope connects the motor module 101 and the mass module 103, the fixing component 2 connects the rope and the mass module 103, the pulley system changes the traction direction of the rope, and the gearbox changes the traction speed of the rope. Specifically, the fixing component 2 can be in the form of a car, a hook, or a mechanical claw, depending on the specific structure of the mass block in the mass module. Through the mass traction module, the mass module can be controlled by the motor module to move in a first direction parallel to the ground and a second direction perpendicular to the ground, thereby enabling free movement of the mass module between stacking platforms at different altitudes.

[0052] The motor module is capable of four-quadrant operation and is the hub of energy conversion. For example, as Figure 4As shown, when the support module includes an upper stacking platform 3 and a lower stacking platform 4, if there is excess power from the power grid, the motor module 101 absorbs the excess power and then lifts the drive and mass traction module 104 to move the mass module 103 from the lower stacking platform 4 to the upper stacking platform 3, realizing the conversion of electrical energy into gravitational potential energy; when there is insufficient power from the power grid, the motor module 101 drives the mass traction module 104 to move the mass module 103 from the upper stacking platform 3 to the lower stacking platform 4. During this process, the heavy object is lowered and drives the motor module 101 to generate electrical energy, realizing the conversion of gravitational potential energy into electrical energy.

[0053] In one embodiment, the topology of the power electronic converter module, determined according to capacity and voltage requirements, should enable bidirectional power transmission and control each switching device based on the received PWM waveform. In a specific embodiment, the power electronic converter modules form a DC loop, with a voltage stabilizing capacitor maintaining DC-side voltage stability. In this example, the power storage module... Figure 4 and Figure 5 Represented by a DC voltage source, this power-type energy storage module is specifically composed of high-power-density energy storage devices, such as supercapacitors, battery packs, or flywheel energy storage modules. Preferably, supercapacitors are used in the power-type energy storage module to achieve better dynamic response and extend system life. The power-type energy storage module is connected to the gravity energy storage device through the power electronic converter module.

[0054] In one specific implementation, such as Figure 4 As shown, the power-type energy storage module is connected to the DC side of the power electronic converter module; or, as... Figure 5 As shown, the power-type energy storage module is connected to the rectifier side of the power electronic converter module; or, as... Figure 6 As shown, the power-type energy storage module is connected to the inverter side of the power electronic converter module. Wherein, as... Figure 4As shown, when the power-type energy storage module 1 is connected to the DC side of the power electronic converter module 102, it is connected to the DC side of the power electronic converter module 102 through the transformer circuit 5. The design of the transformer circuit 5 can reduce the capacity configuration requirements of the power-type energy storage module 102, reduce system costs, and realize bidirectional energy exchange between the power-type energy storage module 102 and the DC side. Furthermore, connecting to the DC side of the power electronic converter module helps maintain DC side voltage stability. When the power-type energy storage module is connected to the rectifier side (machine side) of the power electronic converter module, it can reduce the output pulsation of the motor module, which is more conducive to the stable operation of the quality module and more effective in reducing motor module losses. When the power-type energy storage module is connected to the inverter side (grid side) of the power electronic converter module, it can better suppress fluctuations in grid-side exchange power, which is more conducive to the safe and stable operation of the power grid. In practical applications, the connection method of the power-type energy storage module can be selected according to needs, and this embodiment of the invention does not limit this.

[0055] More specifically, when the composite gravity energy storage system is connected to a high-voltage, high-capacity scenario of 10kV or above, the power electronic converter module adopts a cascaded full-bridge or modular multilevel topology, and the power-type energy storage module is the DC support capacitor in the power electronic converter module. This is more suitable for applications in high-voltage, high-capacity situations.

[0056] As shown in Figures 7(a) to 7(d), the power-type energy storage module is used to compensate for the fluctuations in active power during the start-up and braking phases of the motor module or to provide millisecond-level or higher rapid power compensation to the grid. Specifically, the power-type energy storage module is used to provide power compensation equal to the fluctuation when the fluctuation in active power of gravity energy storage or the grid is positive; and to absorb excess power compensation equal to the fluctuation when the fluctuation in active power of gravity energy storage or the grid is negative. In particular, the power-type energy storage module can not only compensate for the fluctuations in active power during the operation of the gravity energy storage device itself, but also meet the rapidly fluctuating power demands of the grid (such as inertia support and suppression of new energy output fluctuations), making the gravity energy storage power itself stable.

[0057] Specifically, the forces acting on the mass module during its motion can be described by equation (1):

[0058]

[0059] In the formula, This indicates the quality of the quality module. This represents the acceleration of the mass module. This represents the gravitational acceleration of the mass module.

[0060] The switching power of the quality module can be described by equation (2):

[0061]

[0062] In the formula, The total power of the mass module; The constant power of the mass module is a constant. Let be the fluctuating power of the mass module, and be a variable. Specifically, it can be expressed as:

[0063]

[0064]

[0065] In the formula, This indicates the speed of the quality module.

[0066] Integrating both sides of equation (1) yields equation (5), and the energy of the mass module can be described by equation (6):

[0067]

[0068]

[0069] In the formula, The total energy of the mass module; The gravitational potential energy of the mass module; This is the kinetic energy of mass module 1.

[0070] In this embodiment, the vertically upward direction is taken as the positive reference direction, and power and energy are positively represented by absorption. The changes in various physical quantities are as follows:

[0071] When starting in electric mode ; ; ; ; Increase; Increase; Increase.

[0072] When the electric mode is at constant speed ; ; ; ; Increase; constant; Increase.

[0073] Braking in electric mode ; ; ; ; Increase; reduce; Increase.

[0074] When starting in power generation mode ; ; ; ; reduce; Increase; reduce.

[0075] Constant speed in power generation mode ; ; ; ; reduce; constant; reduce.

[0076] Braking in generator mode ; ; ; ; reduce; reduce; reduce.

[0077] Therefore, based on the above force analysis, in order to suppress power fluctuations, the fluctuation amount of active power needs to be controlled. Provide compensation. The size of the variable determines the power of the power storage module. According to equations (5) and (6), the power fluctuation... The integral over time is the kinetic energy of the mass module. The change can be achieved through The size determines the capacity of the power storage module.

[0078] It should be noted that the above is a general discussion of various gravity energy storage technologies. The above model applies to the analysis of all gravity energy storage technologies. Therefore, it also has general applicability to the selection analysis of power-type energy storage modules in hybrid energy storage technologies that combine power-type energy storage modules and gravity energy storage. Furthermore, the above analysis is based on the operation of a single mass block. When a mass module comprises several mass blocks, the selection requirements for the actual power-type devices can be obtained through a simple superposition relationship by determining the number of mass blocks operating simultaneously based on the actual situation.

[0079] Using the above method, the capacity and power configuration of the power-type energy storage module in the composite gravity energy storage system can be completed. In the specific implementation process, based on the aforementioned analysis of power fluctuations... The sign of P determines the control mode of the power-type energy storage module. When When P>0, the gravity energy storage device needs to absorb additional power. To maintain a constant power exchange, the power-type energy storage module outputs power to compensate for the magnitude of the power loss. The power deficit of P. When When P < 0, the gravity energy storage device will release additional power. To maintain a constant power exchange, the control power-type energy storage module absorbs power to compensate for the magnitude of the power loss. Excess power of P.

[0080] In one embodiment, the composite gravity energy storage system further includes: a control system, which controls the motor module through the power electronic converter module according to the operating state of the power grid; determines the configuration capacity of the power-type energy storage module based on the fluctuation of the active power; and controls the power-type energy storage module to perform compensation through the power electronic converter module. Specifically, the control system can issue control signals, such as generating PWM waveforms, to control each switching device in the power electronic converter module; thereby realizing the control of the motor module or the control of the compensation amount of the power-type energy storage module.

[0081] Specifically, during a single operation of the composite gravity energy storage system, the capacity of the power-type control module is configured using a first, second, or third configuration capacity, depending on the compensation strategy. When the power-type energy storage module is controlled using a gravity potential energy conversion power compensation strategy, its capacity is configured using the first configuration capacity, calculated based on the mass of the mass module, its operating speed, and the efficiency of the motor module. When the power-type energy storage module is controlled using a trapezoidal compensation strategy, its capacity is configured using the second configuration capacity, calculated based on the first configuration capacity, the speed and acceleration of the mass module during startup, and the energy absorbed. When the power-type energy storage module is controlled using a rectangular compensation strategy, its capacity is configured using the third configuration capacity, calculated based on the first configuration capacity, the efficiency of the motor module, the operating speed of the mass module, and the acceleration of the mass module during startup. The specific calculation formulas for the first, second, and third configuration capacities are detailed in the following section on the specific calculation process of the control method, and will not be repeated here.

[0082] The above analysis focuses on the operation of a single mass module in a combined gravity energy storage system. Considering the significant power stabilization requirements of the grid in practice, the combined gravity energy storage system will operate continuously in either uplink or downlink conditions. Unlike pumped hydro storage, the mass modules in gravity energy storage are discrete. Therefore, after a motor module moves a mass module via the mass traction module, time is required for the mass traction module to reset. During this reset time, the motor module cannot complete the conversion between electrical energy from the grid and the gravitational potential energy of the mass module, resulting in zero power exchange between the motor module and the grid. This leads to significant fluctuations in power exchange during continuous operation, especially without considering multi-machine coordinated control for power complementarity.

[0083] As shown in Figures 8(a) to 8(f), when the composite gravity energy storage system is running stably and continuously, the power-type energy storage module is also used to discharge during the upward movement of the mass module and to charge during the reset of the mass traction module; wherein, the discharge energy is the first exchange energy 27 of the power-type energy storage module, and the charging energy is the second exchange energy 28 of the power-type energy storage module; considering the energy conservation constraint, the first exchange energy 27 of the power-type energy storage module and the second exchange energy 28 of the power-type energy storage module will be equal.

[0084] When the composite gravity energy storage system is operating stably and continuously, the power-type energy storage module is also used to charge the mass module during its descent and to discharge it during the mass traction module's reset. The charging energy is the first exchange energy 27 of the power-type energy storage module, and the discharging energy is the second exchange energy 28 of the power-type energy storage module. Considering energy conservation constraints, the first exchange energy 27 and the second exchange energy 28 of the power-type energy storage module will be equal.

[0085] As shown in Figures 8(a) to 8(f), the exchange power curves under the aforementioned different conditions are shown. Although the expressions for the exchange power curves are different, since the aforementioned compensation strategy only changes the exchange power by time-shifting the energy, the integrals of the different exchange power curves are the same. Therefore, the first exchange energy 27 and the second exchange energy 28 of the power-type energy storage module can be expressed by equation (27):

[0086]

[0087] in, The first exchange energy 27 of the power-type energy storage module or the second exchange energy 28 of the basic power-type energy storage module; For runtime; A running cycle includes the running time. Reset time of traction module ; To exchange power.

[0088] Accordingly, the configuration of power-type energy storage modules in the compensation method based on stable continuous operation power exchange should consider whether to adopt any of the aforementioned compensation methods based on gravitational potential energy conversion power, trapezoidal compensation, or rectangular compensation (these three are collectively referred to as discrete operation-based compensation strategies). If adopted, the final determined configuration capacity of the power-type energy storage modules should be [missing information]. The most technically and economically superior among the first, second, or third configuration capacities (depending on the discrete operation compensation strategy employed), for example, from an economic perspective, could be the one employing... Alternatively, the lowest cost among the first, second, and third configuration capacities can be used as the configuration capacity; furthermore, from a technical perspective, it is also possible to... The larger value among the first configuration capacity, the second configuration capacity, and the third configuration capacity is selected as the configuration capacity.

[0089] This control strategy is designed for continuous operation of gravity energy storage, and utilizes the power-type energy storage module of the composite gravity energy storage to solve the problem of power fluctuation caused by the discretization of the gravity energy storage medium.

[0090] The composite gravity energy storage system provided in this invention utilizes a power-type energy storage module to provide buffer energy required for the start-up and shutdown process of the motor module, thereby improving the cycle efficiency of the gravity energy storage system, extending the service life of the motor, and significantly improving resource utilization and the overall benefits of the system. The composite gravity energy storage system proposed in this invention has advantages such as large energy storage capacity, low cost, high safety, high cycle efficiency, no environmental pollution, and minimal geographical limitations. Compared with other single-type energy storage technologies, it has significant advantages, can adapt to distributed and large-scale applications, and has broad application prospects.

[0091] This invention also provides a control method for a composite gravity energy storage system, comprising: acquiring the operating status of the power grid or receiving dispatch instructions from the power grid; controlling the gravity energy storage device to convert excess electrical energy from the power grid into gravitational potential energy or to release gravitational potential energy back into the power grid when the power grid is insufficient, based on the operating status of the power grid or the received dispatch instructions from the power grid; and controlling a power-type energy storage module to compensate for fluctuations in active power during the operation of the gravity energy storage device or to provide millisecond-level or higher rapid power compensation to the power grid.

[0092] The control method for the composite gravity energy storage system provided in this invention combines the advantages of both gravity energy storage technology and power-type energy storage technology. This overcomes the issues of output power fluctuation and the inability to achieve millisecond-level or higher response times inherent in gravity energy storage technology, thus contributing to the safe and stable operation of the power grid. It achieves safe and reliable large-scale energy storage while effectively meeting the needs of stable grid or load operation and efficient power conversion.

[0093] Currently, in systems that utilize gravity energy storage, such as Figure 9 The figure shows a schematic diagram of the traction force curve 10 and the actual running speed curve 11 in the upward waveform of conventional speed detection control. The main process is to change the torque of the motor to provide the acceleration required for the mass block to start moving. When the speed reaches the rated speed, the acceleration torque is stopped. Due to inertia, the speed of the mass block will exceed the rated speed. Therefore, a reverse braking torque needs to be added to reduce the speed to the rated value. This process is repeated until the system stabilizes. On the speed curve, this is reflected as a damped oscillation, and on the torque curve, it is reflected as a rapidly alternating torque.

[0094] Clearly, this control method applies control torque by detecting when the actual speed exceeds the rated value. While this method is simple, it suffers from unfavorable operating conditions due to torque and speed fluctuations. This negatively impacts system stability and response speed, while also exacerbating losses and reducing efficiency. Essentially, this control method applies braking torque only when the speed reaches the rated speed. At this point, the slope of the mass block's velocity curve is not zero, meaning its acceleration is not zero, thus its speed cannot immediately stabilize at the rated speed.

[0095] To avoid the adverse operating conditions caused by this control method, this invention proposes a control method that can immediately stabilize the speed at the rated speed, such as... Figure 10 and Figure 11 As shown, the basic idea is to ensure that the mass block has zero acceleration when it reaches its rated speed. According to Newton's second law, the net external force on the mass block should be zero, meaning the motor module should provide torque equal to the mass block's weight. To ensure that the speed is exactly at the rated speed when the torque returns to the mass block's weight, and to accurately depict the curve shape for the power storage module to supplement active power, it is necessary to obtain the mathematical analytical expressions for the torque curve, speed curve, and power curve.

[0096] Assuming the asynchronous motor used in practice is an inertial element, its response to a step command is exponential, and let the horizontal segment of its traction force response curve be... Ascending segment With the descent segment They are respectively:

[0097]

[0098]

[0099]

[0100] Among them, time This is the initial coefficient of the traction force. Let A be the final value coefficient of the traction force, and let A be a constant related to the motor used. To simplify the analysis, considering the combined analysis of the above three traction forces and the gravity of the DC module, the net external force on the mass module can be uniformly expressed as:

[0101]

[0102] To simplify the analysis, this example assumes the existence of three steady-state traction forces: The velocity response curve can be calculated using the following formula:

[0103]

[0104] in, This represents the initial moment of the change in traction force. Let the time elapsed between the changes in traction force be taken as... According to equation (12), the resultant external force can be obtained. The resulting velocity and acceleration response curves:

[0105]

[0106]

[0107] In particular, when the traction coefficient satisfies equation (15), equations (13) and (14) can be further simplified to equations (16) and (17):

[0108]

[0109]

[0110] in It is a constant. , and .

[0111] At this point, we can draw a schematic diagram of the traction force and velocity curves of the mass block as it moves downward and upward, and the schematic diagram of the exchange power can be drawn according to equation (18):

[0112]

[0113] Figure 10 and Figure 11The following diagrams are provided: the downlink waveform diagram of the mass module in the composite gravity energy storage system and the uplink waveform diagram of the mass module in the composite gravity energy storage system. Figure 10 and Figure 11 From the actual exchange power curve, the ideal exchange power curve, the energy released by the power-type energy storage module under the ideal exchange power curve, and the energy absorbed by the power-type energy storage module under the ideal exchange power curve, it can be seen that there is a large power overshoot in the initial stage of deceleration during the downlink process and the final stage of acceleration during the uplink process. This power overshoot will have an adverse effect on the system.

[0114] Gravitational potential energy of a composite gravity energy storage system ,kinetic energy With gravitational potential energy power The expressions are shown in equations (19) to (21):

[0115]

[0116]

[0117]

[0118] According to equations (19) to (21), we can obtain Figure 12 A schematic diagram illustrating the changes in stored energy and power of a composite gravity energy storage system, including gravitational potential energy curve 16 and gravitational potential energy to power conversion curve 17. From... Figure 12 The power flow relationship of the composite gravity energy storage system can be seen as follows:

[0119] When the mass is in the upward acceleration phase, the system absorbs energy from the power grid and converts it into the gravitational potential energy and kinetic energy of the mass.

[0120] When the mass is in the upward deceleration phase, the system absorbs energy from the power grid and converts it, along with the kinetic energy of the mass, into the gravitational potential energy of the mass.

[0121] When the mass is in the downward acceleration phase, the system converts the gravitational potential energy of the mass into energy emitted to the system and the kinetic energy of the mass.

[0122] When the mass is in the downward deceleration phase, the system converts the mass's gravitational potential energy and kinetic energy into energy emitted to the system.

[0123] In summary, kinetic energy exists only during upward or downward motion, is generated during the acceleration phase of motion, and decreases during the deceleration phase.

[0124] Furthermore, by comparing the gravitational potential energy conversion power curve with the system power curve, the compensation command required for the power-type energy storage device can be obtained. Among them, the gravitational potential energy conversion power curve 17 is a relatively ideal power response curve and can be used as the compensation target for the power-type energy storage device. Figure 13 compares the actual power response curve 12 with the gravitational potential energy conversion power curve 17. The area where the actual power response curve 12 is smaller than the area where the gravitational potential energy conversion power curve 17 is the energy released by the power-type energy storage module under the relatively ideal exchange power curve 18; the area where the actual power response curve 12 is larger than the area where the gravitational potential energy conversion power curve 17 is the energy absorbed by the power-type energy storage module under the relatively ideal exchange power curve 19.

[0125] Since the velocity of the mass block is zero at both the beginning and end of the operation, meaning there is no kinetic energy at either stage, the area of ​​the energy 18 released by the power-type energy storage module under the ideal power exchange curve is equal to the area of ​​the energy 19 absorbed by the power-type energy storage module under the ideal power exchange curve, and is also equal to the maximum kinetic energy that the mass block can possess. Based on this, this compensation method is called the compensation method based on gravitational potential energy conversion power.

[0126] Since the area of ​​the energy 18 released by the power-type energy storage module under the ideal exchange power curve is equal to that of the energy 19 absorbed by the power-type energy storage module under the ideal exchange power curve, if the control method of compensating the actual power response curve 12 to the gravitational potential energy conversion power curve 17 by the power-type energy storage module 9 is adopted, the power-type energy storage module can achieve energy conservation within one motion cycle of the mass block without considering losses, that is, no external additional energy is required.

[0127] At its most basic level, as shown in Figures 13(a) and 13(b), the compensation method based on the conversion of gravitational potential energy into power makes the originally irregular exchange power curve regular and symmetrical. By suppressing the power pulses caused by motor start-up and shutdown, the exchange power curve becomes smoother, reducing grid connection impact and facilitating the stable operation of the power grid.

[0128] The capacity of the power storage module required for the compensation method based on gravitational potential energy conversion power is the first configuration capacity. The maximum fluctuation of the kinetic energy of the mass module can be obtained from equation (21):

[0129]

[0130] in This represents the maximum speed at which the quality module operates. For motor efficiency, the speed at which the specific mass module operates can be the maximum speed, average speed, or weighted average speed, etc., and this embodiment of the invention does not limit this.

[0131] Furthermore, without considering losses and ensuring that the power-type energy storage module can achieve energy conservation during a charge-discharge cycle, in addition to the aforementioned compensation method based on gravitational potential energy conversion power, this embodiment of the invention also proposes a trapezoidal compensation method and a rectangular compensation method.

[0132] Furthermore, such as Figure 14 As shown, a trapezoidal-based compensation method is proposed based on the compensation method for gravitational potential energy conversion power. Although the compensation method based on gravitational potential energy conversion power makes the originally irregular exchange power curve regular and symmetrical, its exchange law curve is still nonlinear, which brings inconvenience to precise power control. Based on the above considerations, the trapezoidal-based compensation method further linearizes the exchange power curve, reducing the control difficulty of the composite gravity energy storage system.

[0133] Based on equations (13), (14), (20), and (21), the required configuration capacity of the power storage module based on the trapezoidal compensation method is the second configuration capacity. It can be represented as:

[0134]

[0135]

[0136]

[0137]

[0138] in, For the speed of the quality module during the startup phase; Energy absorbed by the quality module during the startup phase; This refers to the acceleration of the mass module during the upward uniform acceleration phase.

[0139] Furthermore, based on the trapezoidal compensation method, a rectangular compensation method is proposed. While the trapezoidal compensation method achieves linearization of the exchange power curve, it still exhibits an upward phase, i.e., the full-power response phase. The time corresponding to this phase is the full-power response time of the energy storage system. As an energy dispatcher, the energy storage system participates in the grid's operation and control. Its fundamental role is to decouple electrical energy in time and space to achieve real-time supply and demand matching. When an energy storage system is activated, it often indicates a supply-demand mismatch (such as fluctuations in load demand or renewable energy output). In such cases, the energy storage system's rapid response capability becomes particularly important.

[0140] Based on this, the rectangular compensation method, building upon the trapezoidal compensation method, increases the full-power response time of the composite gravity energy storage system from the original motor response time level to the power storage device response time level, greatly improving the response speed of the composite gravity energy storage system. Because the exchange power response curve of the rectangular compensation method is very close to a matrix when viewed on the original time scale, this method is named accordingly.

[0141] Based on equations (20) and (25), the required configuration capacity of the power storage module based on the trapezoidal compensation method is the third configuration capacity. It can be represented as:

[0142]

[0143] It should be noted that the system switching power curve 23 obtained based on the rectangular compensation method differs from the aforementioned ideal switching power curve 13. The ideal switching power curve 13 only reflects the ideal form of the system switching power; for example... Figure 15 As shown, the system exchange power curve 23 obtained by the rectangular compensation method not only achieves the ideal system exchange power curve shape, but also realizes the energy conservation of the power storage module, thus providing a superior response.

[0144] The above is an operational analysis of a single operation of the composite gravity energy storage system, specifically for a single mass block. When the composite gravity energy storage system is running stably and continuously, the power-type energy storage module is controlled to discharge during the mass module's upward movement and charge during the mass traction module's reset; it is also controlled to charge during the mass module's downward movement and discharge during the mass traction module's reset.

[0145] Furthermore, when the composite gravity energy storage system is running stably and continuously, the charging energy or discharging energy of the power-type energy storage module is determined based on the ratio of the integral of the exchange power to the operating cycle; combined with the compensation strategy adopted for a single operation, the capacity of the power-type energy storage module is configured according to the technical and economic advantage of the charging energy or discharging energy in one cycle compared with the first configuration capacity, the second configuration capacity, or the third configuration capacity.

[0146] Specifically, the calculation process for the charging or discharging energy of the power-type energy storage module is described in the above-mentioned composite gravity energy storage system, and will not be repeated here.

[0147] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A composite gravity energy storage system, characterized in that, include: Gravity energy storage devices and power-type energy storage modules, The gravity energy storage device is used to absorb excess electrical energy from the power grid or to release electrical energy when the power grid is insufficient. The power-type energy storage module is used to compensate for the fluctuation of active power during the operation of the gravity energy storage device or to provide the grid with millisecond-level or higher fast power compensation. The gravity energy storage device includes: a motor module and a mass module; When the composite gravity energy storage system is running for a single time, the capacity of the power-type energy storage module is configured with a first configuration capacity, a second configuration capacity, or a third configuration capacity, depending on the different compensation strategies of the power-type energy storage module in the composite gravity energy storage system. When the power-type energy storage module is controlled using a power compensation strategy based on gravitational potential energy conversion, the capacity of the power-type energy storage module is configured using a first configuration capacity, which is calculated based on the mass of the mass module, the speed at which the mass module operates, and the efficiency of the motor module. When the power-type energy storage module is controlled using a trapezoidal compensation strategy, the capacity of the power-type energy storage module is configured using a second configuration capacity, which is calculated based on the first configuration capacity, the speed and acceleration of the mass module during the startup phase, and the energy absorbed. When the power-type energy storage module is controlled using a rectangular compensation strategy, the capacity of the power-type energy storage module is configured using a third configuration capacity, which is calculated based on the first configuration capacity, the efficiency of the motor module, the operating speed of the mass module, and the acceleration of the mass module during the startup phase.

2. The composite gravity energy storage system according to claim 1, characterized in that, The power-type energy storage module is specifically used to provide power compensation equal to the amount of power fluctuation when the fluctuation of gravity energy storage or grid active power is positive; and to absorb excess power equal to the amount of power fluctuation when the fluctuation of gravity energy storage or grid active power is negative.

3. The composite gravity energy storage system according to claim 1, characterized in that, The gravity energy storage device includes: a gravity energy storage module and a power electronic converter module. The motor module is connected to the gravity energy storage module and is used to control the movement of the gravity energy storage module to absorb or release electrical energy. The power electronic converter module is connected to the power grid at one end and to the motor module at the other end, and is used for the control of the motor module.

4. The composite gravity energy storage system according to claim 3, characterized in that, The gravity energy storage module includes: a mass traction module and a support module; The support module is a natural terrain or man-made structure with a height difference, used to provide the height difference required for the movement of the mass module and to provide support for the mass module; The mass traction module is used to traction the mass module to move upward or downward under the control of the motor module; The mass module is used to convert electrical energy into gravitational potential energy for storage or to convert gravitational potential energy into electrical energy for release.

5. The composite gravity energy storage system according to claim 3, characterized in that, The power-type energy storage module is connected to the gravity energy storage device through the power electronic converter module. Specifically, the power-type energy storage module is used to compensate for the fluctuation of active power during the start-up and braking phases of the motor module.

6. The composite gravity energy storage system according to claim 5, characterized in that, The power-type energy storage module is connected to the DC side of the power electronic converter module; or, the power-type energy storage module is connected to the AC rectifier side of the power electronic converter module; or, the power-type energy storage module is connected to the AC inverter side of the power electronic converter module.

7. The composite gravity energy storage system according to claim 5, characterized in that, The power-type energy storage module includes any one of supercapacitors, batteries, or flywheel energy storage; or... When the composite gravity energy storage system is connected to a high-voltage, high-capacity scenario of 10kV or above, the power electronic converter module adopts a cascaded full-bridge or modular multilevel topology, and the power-type energy storage module is the DC support capacitor in the power electronic converter module.

8. The composite gravity energy storage system according to claim 4, characterized in that, Also includes: The control system controls the motor module through the power electronic converter module according to the operating status of the power grid; The configuration capacity of the power-type energy storage module is determined based on the fluctuation of the active power, and the power-type energy storage module is controlled by the power electronic converter module to perform compensation.

9. The composite gravity energy storage system according to claim 8, characterized in that, When the composite gravity energy storage system is running stably and continuously, the power-type energy storage module is also used to discharge during the upward movement of the mass module and charge during the reset of the mass traction module; to charge during the downward movement of the mass module and to discharge during the reset of the mass traction module.

10. The composite gravity energy storage system according to claim 9, characterized in that, When the composite gravity energy storage system is running stably and continuously, the charging energy or discharging energy of the power-type energy storage module is determined based on the ratio of the integral of the exchange power to the operating cycle. The configuration capacity of the power-type energy storage module is configured according to the technical and economic advantages of the charging energy or discharging energy in one cycle and the first, second, or third configuration capacity, in combination with the compensation strategy adopted for a single operation.

11. A control method for a composite gravity energy storage system, characterized in that, include: To obtain the operating status of the power grid or receive dispatch instructions from the power grid; Based on the operating status of the power grid or by receiving dispatch instructions from the power grid, the gravity energy storage device is controlled to convert excess electrical energy in the power grid into gravitational potential energy, or to convert gravitational potential energy into electrical energy and feed it back into the power grid when the power grid is insufficient. The control power type energy storage module compensates for the fluctuation of active power during the operation of the gravity energy storage device or provides millisecond-level or higher fast power compensation to the grid. The gravity energy storage device includes: a motor module and a mass module; When the composite gravity energy storage system operates for a single time, the capacity of the power-type energy storage module is configured using a first configuration capacity, a second configuration capacity, or a third configuration capacity, depending on the different compensation strategies of the power-type energy storage module in the composite gravity energy storage system: When the power-type energy storage module is controlled using a power compensation strategy based on gravitational potential energy conversion, the capacity of the power-type energy storage module is configured using a first configuration capacity, which is calculated based on the mass of the mass module, the speed at which the mass module operates, and the efficiency of the motor module. When the power-type energy storage module is controlled using a trapezoidal compensation strategy, the capacity of the power-type energy storage module is configured using a second configuration capacity, which is calculated based on the first configuration capacity, the speed and acceleration of the mass module during the startup phase, and the energy absorbed. When the power-type energy storage module is controlled using a rectangular compensation strategy, the capacity of the power-type energy storage module is configured using a third configuration capacity, which is calculated based on the first configuration capacity, the efficiency of the motor module, the operating speed of the mass module, and the acceleration of the mass module during the startup phase.

12. The control method for the composite gravity energy storage system according to claim 11, characterized in that, Also includes: When the composite gravity energy storage system operates for a single time, the capacity of the power-type energy storage module is configured according to a first configuration capacity, a second configuration capacity, or a third configuration capacity, based on different compensation strategies for the power-type energy storage module; wherein, When the power-type energy storage module is controlled using a power compensation strategy based on gravitational potential energy conversion, the capacity of the power-type energy storage module is configured using a first configuration capacity, which is calculated based on the mass of the mass module, the speed at which the mass module operates, and the efficiency of the motor module. When the power-type energy storage module is controlled using a trapezoidal compensation strategy, the capacity of the power-type energy storage module is configured using a second configuration capacity, which is calculated based on the first configuration capacity, the speed and acceleration of the mass module during the startup phase, and the energy absorbed. When the power-type energy storage module is controlled using a rectangular compensation strategy, the capacity of the power-type energy storage module is configured using a third configuration capacity, which is calculated based on the first configuration capacity, the efficiency of the motor module, the operating speed of the mass module, and the acceleration of the mass module during the startup phase.

13. The control method for the composite gravity energy storage system according to claim 12, characterized in that, Also includes: When the composite gravity energy storage system is running stably and continuously, the power-type energy storage module is controlled to discharge during the upward movement of the mass module and charge during the reset of the mass traction module; it is also controlled to charge during the downward movement of the mass module and discharge during the reset of the mass traction module.

14. The control method for the composite gravity energy storage system according to claim 13, characterized in that, Also includes: When the composite gravity energy storage system is running stably and continuously, the charging energy or discharging energy of the power-type energy storage module is determined based on the ratio of the integral of the exchange power to the operating cycle. Based on the compensation strategy adopted for a single operation, the configuration capacity of the power-type energy storage module is configured according to the technical and economic advantages of the charging energy or discharging energy in one cycle compared with the first configuration capacity, the second configuration capacity, or the third configuration capacity.

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