Gravity energy storage system cooperative braking control method and device

Abstract

The application discloses a gravity energy storage system cooperative braking control method and device, and relates to the technical field of gravity energy storage. The method is used to solve the problems of poor power stability, dependence on imported core components, high transformation cost, insufficient safety guarantee and low energy efficiency of the existing shaft type gravity energy storage release control technology. The method establishes state self-checking by presetting braking torque, avoids speed impact and out-of-control risk in the initial stage of the heavy object falling, adopts a hierarchical brake release mode to provide reliable data support for precise control, takes speed closed loop as the core, equally distributes braking force between the main braking unit and the cooperative braking unit according to the proportion, realizes uniform speed falling of the heavy object, guarantees stable release power output, meets the grid connection requirement, and automatically starts hydraulic energy recovery under the uniform speed working condition to convert the braking mechanical energy into hydraulic energy storage, thereby improving the overall energy efficiency of the system.

Description

Technical Field

[0001] This invention relates to the field of gravity energy storage technology, and more specifically to a method and device for coordinated braking control of gravity energy storage systems. Background Technology

[0002] Vertical Gravity Energy Storage System (VGESS) is an important branch of Gravity Energy Storage System (GESS). With its stable power output, large storage capacity, and strong adaptability, it has become one of the key technological pathways for large-scale energy storage in new power systems. This system achieves bidirectional conversion between electrical energy and gravitational potential energy through the lifting and lowering of a weight within a vertical shaft, and has broad application prospects in scenarios such as renewable energy grid integration, grid peak shaving, and emergency power supply.

[0003] Currently, vertical shaft gravity energy storage systems generally employ a motor-driven speed regulation scheme during the energy release and weight reduction phase. This involves using an imported variable frequency motor and a dedicated control module to adjust the descent speed of the load, thereby smoothing power fluctuations and recovering braking energy. This approach requires a complete replacement of the system's power unit, relying on imported core components. This not only results in high costs and long construction periods but also significant speed fluctuations during acceleration and deceleration, making it difficult to meet the requirements for stable grid-connected power. Furthermore, the system lacks a fast and reliable emergency braking structure, posing safety hazards during hoisting and operation. The motor start-up, shutdown, and frequency conversion processes also generate additional energy losses, leading to low energy release efficiency.

[0004] In summary, existing vertical shaft gravity energy storage and release control technologies generally suffer from problems such as poor power stability, reliance on imported core components, high retrofit costs, insufficient safety guarantees, and low energy efficiency, making it difficult to meet the upgrade requirements of engineering, self-reliance, and high efficiency. Summary of the Invention

[0005] This invention provides a method and apparatus for coordinated braking of a gravity energy storage system, which addresses the common problems of poor power stability, reliance on imported core components, high retrofitting costs, insufficient safety assurance, and low energy efficiency in existing vertical shaft gravity energy storage release control technologies.

[0006] This invention provides a method for coordinated braking control of a gravity energy storage system, comprising:

[0007] Upon receiving the energy release and grid connection command, the main braking unit, the cooperative braking unit, and the sensing unit perform preset braking torque establishment and status self-check;

[0008] Send a step-by-step release command to the normally closed mechanical brake to make the heavy object start to fall under its own weight, and obtain the actual falling speed, falling acceleration and falling suspension tension of the heavy object;

[0009] With the goal of uniform descent, the difference in descent speed is determined based on the target descent speed and the actual descent speed. When the difference in descent speed is not equal to zero, the main braking unit and the cooperative braking unit are coordinated and adjusted. The main braking unit and the cooperative braking unit distribute the total braking force in a 50 / 50 ratio. When it is determined that the object is falling at a uniform speed and the pressure of the hydraulic system included in the main braking unit is greater than a set value, the cooperative braking unit is controlled to convert the braking mechanical energy generated during the descent of the object into hydraulic energy and send it to the accumulator.

[0010] When the sensing unit determines that the remaining stroke of the heavy object is less than a preset threshold, it controls the main braking unit and the cooperative braking unit to perform multi-stage deceleration cooperative braking so that the heavy object decelerates smoothly.

[0011] When the actual falling speed of the heavy object is determined to be zero, a synchronous timing brake command is sent so that the normally closed mechanical brake tightens the drum to achieve rigid locking, the main braking unit maintains the excitation current and torque, the cooperative braking unit maintains the braking pressure and stops supplying hydraulic energy to the accumulator.

[0012] This invention provides a coordinated braking control device for a gravity energy storage system, comprising:

[0013] The initialization unit is used to receive the energy release and grid connection command, and the main braking unit, the cooperative braking unit, and the sensing unit perform preset braking torque establishment and status self-check.

[0014] The data acquisition unit is used to send a step-by-step release command to the normally closed mechanical brake so that the heavy object can start to fall under its own gravity, and to acquire the actual falling speed, falling acceleration and falling suspension tension of the heavy object.

[0015] The secondary braking modulation unit is used to determine the difference in falling speed based on the target speed of the falling object and the actual falling speed, with the goal of uniform descent. When the difference in falling speed is not equal to zero, the main braking unit and the cooperative braking unit are coordinated and adjusted. The main braking unit and the cooperative braking unit distribute the equivalent braking force of the secondary braking in a 50 / 50 ratio. When it is determined that the falling object is uniform and the pressure of the main braking unit is greater than a set value, the main braking unit is controlled to convert the braking mechanical energy generated during the falling object into hydraulic energy and send it to the accumulator.

[0016] A multi-level coordination unit is used to control the main braking unit and the coordination braking unit to perform multi-level deceleration coordination braking when the sensing unit determines that the remaining stroke of the heavy object is less than a preset threshold, so as to make the heavy object decelerate smoothly.

[0017] The stopping unit is used to send a synchronous timing brake command when it is determined that the actual falling speed of the heavy object is zero, so that the normally closed mechanical brake tightens the drum to achieve rigid locking, the cooperative braking unit stops the braking pressure and stops the supply of hydraulic energy to the accumulator, and the main braking unit maintains the excitation current and torque.

[0018] This invention provides a gravity energy storage coordinated braking control method and device. The method ensures system stability and controllability during startup by establishing a preset braking torque and performing a self-check, avoiding speed shocks and loss of control risks during the initial descent of the heavy object. A staged brake release method ensures smooth start-up of the heavy object, and real-time acquisition of speed, acceleration, and suspension tension signals provides reliable data support for precise control. With a speed closed loop as the core, the braking force is evenly distributed between the main braking unit (magnetic powder mechanical braking) and the coordinated braking unit (hydraulic passive braking), which can quickly smooth descent speed fluctuations, achieving uniform descent of the heavy object and ensuring stable output of released power to meet grid connection requirements. When the pressure requirement is met during the descent, hydraulic energy recovery is automatically activated, converting braking mechanical energy into hydraulic energy for storage, improving the overall energy efficiency of the system. Two-stage deceleration coordinated braking achieves smooth deceleration of the heavy object, avoiding shutdown shocks; synchronous timing brake locking achieves rigid positioning, improving system operational safety and stability. The entire process is automated, requiring no manual intervention, and the control logic is simple and reliable, effectively improving the safety, stability, and energy utilization rate of the gravity energy storage system's energy release process. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the coordinated braking control method for a gravity energy storage system provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the overall structure of the vertical shaft gravity energy storage system provided in an embodiment of the present invention;

[0022] Figure 3 This is an isometric schematic diagram of the top-level power and braking unit provided in an embodiment of the present invention;

[0023] Figure 4 This is a partial schematic diagram of the main braking and mechanical safety unit provided in an embodiment of the present invention;

[0024] Figure 5 This is a partial schematic diagram of a hydraulic energy recovery unit provided in an embodiment of the present invention;

[0025] Among them, 2-1 heavy object, 2-2 electric generator, 2-3 magnetic powder brake, 2-4 top pulley, 2-5 mechanical speed limiter, 2-6 normally closed brake, 2-7 permanent magnet synchronous motor, 2-8 drum, 2-9 fixed displacement hydraulic motor, 2-10 relief valve, 2-11 throttle valve, 2-12 check valve, 2-13 bladder accumulator, and 2-14 oil tank. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0027] Figure 1 This is a schematic diagram of the coordinated braking control method for a gravity energy storage system provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of a gravity energy storage system provided in an embodiment of the present invention; the following is in conjunction with... Figure 1 and Figure 2 Taking an example, this invention provides a detailed description of the cooperative braking control method for a gravity energy storage system provided in its embodiments. Figure 1 As shown, the method includes the following steps:

[0028] Step 101: Upon receiving the energy release and grid connection command, the main braking unit, the cooperative braking unit, and the sensing unit perform preset braking torque establishment and status self-check.

[0029] Step 102: Send a step-by-step release command to the normally closed mechanical brake to make the heavy object start to fall under its own weight, and obtain the actual falling speed, falling acceleration and falling suspension tension of the heavy object;

[0030] Step 103: With uniform descent as the goal, determine the descent speed difference based on the target descent speed and the actual descent speed. When the descent speed difference is not equal to zero, coordinate the main braking unit and the cooperative braking unit, with the main braking unit and the cooperative braking unit distributing the total braking force in a 50 / 50 ratio. When it is determined that the object is falling at a uniform speed and the pressure of the hydraulic system included in the main braking unit is greater than a set value, control the cooperative braking unit to convert the braking mechanical energy generated during the descent of the object into hydraulic energy and send it to the accumulator.

[0031] Step 104: When the sensing unit determines that the remaining stroke of the heavy object is less than a preset threshold, it controls the basic braking force and the pre-tensioning braking force to perform multi-stage deceleration and coordinated braking so that the heavy object decelerates smoothly.

[0032] Step 105: When it is determined that the actual falling speed of the heavy object is zero, a synchronous timing brake command is sent so that the normally closed mechanical brake tightens the drum to achieve rigid locking, the main braking unit maintains the excitation current and torque, and the cooperative braking unit maintains the braking pressure and stops sending hydraulic pressure to the accumulator.

[0033] It should be noted that the method provided in this embodiment of the invention is executed by a PLC controller.

[0034] Before proceeding to step 101, it is necessary to introduce the gravity energy storage system and its phases.

[0035] like Figures 2-5 As shown, the system includes an energy storage unit, a power transmission unit, a two-stage coordinated braking unit, an energy recovery unit, an operation control and sensing unit, an energy conversion and grid connection unit, and an emergency safety braking unit.

[0036] Specifically, the energy storage unit is used to store gravitational potential energy, provide a vertical lifting channel for heavy objects, and realize the conversion of potential energy into kinetic energy. It includes a vertical shaft, heavy object 2-1, cage, lifting platform, derrick, and heavy object loading, unloading and storage device.

[0037] The power transmission unit is used to transmit the pulling force for lifting heavy objects, realize the bidirectional conversion of electrical energy and mechanical energy, and drive the power generation and lifting operation. It includes an electric generator 2-2, a wire rope, a top pulley 2-4, a drum 2-8, and a drive shaft. The electric generator is used to realize the dual operation of electric lifting and power generation. The top pulley is used to change the traction direction of the wire rope and form a pulley block.

[0038] The secondary coordinated braking unit is used to achieve uniform and stable speed and coordinated speed regulation under motorless traction. It ensures stable energy release power by proportionally distributing braking force between magnetic powder braking and hydraulic braking. It includes a magnetic powder brake 2-3, a fixed-displacement hydraulic motor 2-9, a throttle valve 2-11, a hydraulic station, and an oil tank 2-14. The magnetic powder brake is the main braking unit, which adjusts the braking torque through excitation current to achieve closed-loop speed control. The fixed-displacement hydraulic motor is the coordinated braking unit, providing hydraulic braking force under passive pump operation. The throttle valve is used as a proportional speed limiter to adjust the hydraulic flow to achieve coordinated regulation of braking force. The oil tank provides hydraulic oil for hydraulic braking and constitutes the basic component of the hydraulic station.

[0039] The energy recovery unit converts mechanical energy during braking into hydraulic energy for storage, supplying auxiliary components of the system and improving overall energy efficiency. It includes a fixed-displacement hydraulic motor 2-9 (passive pump mode), a throttle valve 2-11, a bladder accumulator 2-13, hydraulic lines, a check valve 2-12, and a relief valve 2-10. In passive pump mode, the fixed-displacement hydraulic motor converts braking mechanical energy into hydraulic energy. The throttle valve controls the flow rate to ensure stable recovery. The check valve prevents backflow of hydraulic oil from the accumulator, ensuring unidirectional energy recovery. The relief valve limits the maximum pressure in the hydraulic circuit for safety protection.

[0040] The operation control and sensing unit is used for speed measurement, closed-loop control, PID regulation, and status monitoring. It includes a PLC controller, host computer, speed sensor, tension sensor, hydraulic pressure sensor, position sensor, and drive module.

[0041] The energy conversion and grid connection unit is used to convert and lock the electrical energy output by the integrated electric generator to achieve grid-connected power transmission; and to drive the motor by receiving grid power under the improvement working condition. It includes the integrated electric generator 2-2, power electronic converter, transformer, grid connection switch, dq axis control module, and PLL phase-locked module.

[0042] The emergency safety braking unit is used for rapid locking in case of malfunction / overspeed / power failure. It includes a normally closed mechanical brake 2-6, a fault speed limiter 2-5, a fault detection module, and an alarm device.

[0043] In the gravity energy storage system, the secondary coordinated braking module includes a magnetic powder brake as a mechanical braking unit, i.e., the main braking unit; and a fixed-displacement hydraulic motor, throttle valve, and hydraulic station as a hydraulic braking unit, i.e., the coordinated braking unit.

[0044] In this embodiment of the invention, the energy conversion of the gravity energy storage system is divided into an energy storage stage and an energy release stage, wherein each stage includes three periods: acceleration start-up, uniform speed operation, and deceleration braking.

[0045] Specifically, the energy storage stage refers to the external power supply supplying electricity to the motor, which drives the heavy object to rise at a constant speed, with electrical energy mainly converted into gravitational potential energy. Under ideal conditions, the energy storage charging and potential energy dissipation analysis is as follows: the energy storage stage includes three periods: acceleration start-up, constant speed energy storage, and deceleration braking.

[0046] The acceleration motor pulls against gravity, friction, and wind resistance, causing the heavy object to accelerate from rest to a constant speed. The acceleration and height of the accelerating heavy object are determined by the following formulas:

[0047] (1-1)

[0048] (1-2)

[0049] in, Indicates the target acceleration for the accelerated start-up of the energy storage phase, subscript This indicates an increase in energy storage. 1 indicates the acceleration phase; This represents the derivative of the target acceleration rate with respect to time during the energy storage phase, i.e., instantaneous acceleration. Indicates the target velocity of uniform ascent during the energy storage phase, subscript Indicates the target value. This indicates the height to which the heavy object rises during the accelerated start-up phase of the energy storage stage. This indicates the end point of the accelerated start-up phase of the energy storage stage.

[0050] When the uniform-speed energy storage motor reaches its rated speed, the weight is in force balance and rises at a constant speed. The actual rising speed of the weight has a fixed relationship with the motor speed. The actual rising speed and the rising height of the uniform-speed energy storage weight are determined by the following formulas:

[0051] (1-3)

[0052] (1-4)

[0053] in, This indicates the actual rising speed of the uniformly rising energy storage object during the energy storage phase, indicated by the subscript. Indicates the actual value; This represents pi (≈3.1416). Indicates the drum radius, This indicates the drum speed. This represents the angular velocity of the motor (rad / s). This indicates the height to which the weight rises during the uniform energy storage phase; the subscript 2 indicates uniform energy storage. This indicates the end time of the uniform energy storage phase. This indicates the rated speed of the motor (r / min). This indicates the target speed for uniform ascent during the energy storage phase.

[0054] After the decelerating and braking load reaches the energy storage height, it needs to decelerate from its current speed to 0 and enter a stationary standby state. During this stage, although the motor continues to rotate forward, the electromagnetic torque is opposite to the rotational speed, operating in the second quadrant. The acceleration during deceleration and braking in the energy storage stage is negative, and the braking distance needs to be limited. The rising acceleration and rising height of the load during deceleration and braking in the energy storage stage are determined by the following formulas:

[0055] (1-5)

[0056] (1-6)

[0057] in, This indicates the acceleration of the weight during the deceleration braking phase of the energy storage stage. This indicates the end time of deceleration and braking during the energy storage phase. This represents the target velocity of the weight rising at a constant speed during the energy storage phase. This indicates the height to which the load rises during the deceleration and braking phase of the energy storage stage. The subscript 3 indicates deceleration and braking.

[0058] Specifically, the energy release phase is also divided into three periods: acceleration start-up, constant speed operation, and deceleration braking.

[0059] The acceleration phase of the starting load begins with the load accelerating from rest (the load begins to fall and accelerate under gravity). Assuming the load has an initial height and reaches its maximum speed (i.e., grid connection speed) after falling a certain distance, the actual falling height of the load during the energy release phase is determined by the following formula:

[0060] (1-7)

[0061] in, This indicates the actual falling height of the heavy object during the energy release phase, which accelerates its descent. This indicates the end of the accelerated start of the energy release phase. Indicates the energy release phase The actual falling speed of the weight at any given moment.

[0062] The uniformly moving weight always moves at a predetermined constant speed. The falling height of the uniformly moving weight during the energy release phase is determined by the following formula:

[0063] (1-8)

[0064] in, This indicates the actual falling height of the object moving at a constant speed during the energy release phase. This represents the target velocity of the weight falling at a constant speed during the energy release phase. This indicates the end of the accelerated start of the energy release phase. This indicates the end time of the uniform motion during the energy release phase. This indicates the rated speed of the generator during the energy release phase.

[0065] The deceleration and braking gravity energy storage system stops supplying power to the grid, and the falling speed of the heavy object gradually decreases. It then enters a static standby state. The falling height of the weight during the energy release phase, when it decelerates and brakes, is determined by the following formula:

[0066] (1-9)

[0067] in, This indicates the height of the falling object during the deceleration and braking phase of the energy release stage. This represents the acceleration of the decelerating and braking weight during the energy release phase. This indicates the end time of the deceleration and braking during the energy release phase.

[0068] In this embodiment of the invention, when the PLC controller of the gravity energy storage system receives an energy storage command, the PLC controller controls the motor to pull the weight upwards. The motor driving force needs to overcome the weight of the weight, air resistance, and the friction of the pulley system. Taking the upward direction of the weight as positive, the force balance during the energy storage stage is determined by the following formula:

[0069] (1-10)

[0070] in, This indicates that the motor increases traction during the energy storage phase. Indicates the mass of the object. Represents gravitational acceleration. Indicates air resistance, This represents the frictional force of the pulley system.

[0071] In practical applications, the traction force of the motor is determined by the following formula:

[0072] (1-11)

[0073] in, This indicates the motor's output torque. Indicates the transmission ratio. Indicates the efficiency of the transmission system, subscript Indicates transmission efficiency.

[0074] In this embodiment of the invention, the gravity energy storage system adopts a direct drive system, eliminating the intermediate transmission link, thus reducing the transmission ratio. Transmission efficiency Therefore, the traction force increased by the motor can be transformed into:

[0075] (1-12)

[0076] Air resistance is determined by the following formula:

[0077] (1-13)

[0078] in, Indicates the air drag coefficient. Indicates air density, Indicates the windward area of ​​a heavy object. This indicates the actual rate of ascent of the heavy object during the energy storage phase.

[0079] Furthermore, according to formulas (1-12), (1-13), and (1-11), the motor output torque can be simplified as:

[0080] (1-14)

[0081] in, This indicates the load torque during the energy storage phase. This indicates the actual rate of ascent of the heavy object during the energy storage phase.

[0082] In practical applications, the instantaneous power during gravity energy storage, i.e., the traction power of the motor during energy storage, is determined by the following formula:

[0083] (1-15)

[0084] in, Energy storage stage Constant motor traction power, Indicates energy storage stage The actual rising speed of the weight at any given moment.

[0085] In step 101, when the PLC controller of the gravity energy storage system receives the energy release and grid connection command, it first enters the cooperative braking initialization stage, and performs pre-established torque and status self-check on the main braking unit, cooperative braking unit and sensing detection unit to prepare for the smooth lowering of the heavy object.

[0086] In this embodiment of the invention, the main braking unit is a mechanical braking unit, which mainly includes a magnetic powder brake. A pre-excitation operation is performed by applying an initial excitation current, causing the magnetic powder to form a magnetic powder chain under the action of an electromagnetic field, transmitting a preset pre-tensioned braking torque. The principle is that after the magnetic powder brake is energized, the magnetic powder connects the inner and outer rotors under the action of magnetic lines of force, transmitting the braking torque. This operation can eliminate the gap between the wire rope and the transmission mechanism, tension the rope, and prevent vibration and impact caused by the gap when the heavy object is started and lowered, while also preventing initial overspeed.

[0087] Furthermore, the coordinated braking unit is a hydraulic braking unit, which mainly includes a hydraulic motor, a throttle valve, and a hydraulic station. Specifically, the hydraulic station is started to build up pressure to a low pressure, the weight descends and drives the motor, the hydraulic station replenishes oil in a timely manner, and the throttle valve controls the flow rate of the high-pressure oil pump to provide braking force to the motor; its principle is to use the motor in reverse, the weight drives the motor to generate torque, the flow rate of hydraulic oil is controlled to provide counterforce, the oil tank is replenished appropriately, the motor does not consume energy and is completely passive, the opening and closing degree of the valve group can be controlled to adjust the motor braking force, better adapt to the speed adjustment during the descent process.

[0088] Simultaneously complete the calibration and status detection of the speed sensor, tension sensor, displacement sensor, and hydraulic pressure sensor to confirm that the gravity energy storage system meets the requirements for safe start-up and energy recovery operation.

[0089] In step 102, after initialization is complete, a staged release command is sent to the normally closed mechanical brake to allow the load to begin falling under its own weight; the PLC controller acquires the actual falling speed of the load in real time. Falling acceleration And the tension of the suspension during descent.

[0090] Specifically, the actual falling speed of the load is determined by collecting the real-time rotational speed of the drum using a speed sensor, and then combining this with the drum's radius using the following formula:

[0091] (2-1)

[0092] The acceleration of the falling object is calculated by taking the time derivative of the actual falling velocity collected by the sensor, and is determined by the following formula:

[0093] (2-2)

[0094] The suspension tension during descent is the real-time tension borne by the steel wire rope suspending the load. It is determined by collecting basic data through a tension sensor, and combining this data with the total mass of the load, gravitational acceleration, real-time braking damping force, and the load's descent acceleration using the following formula:

[0095] (2-3)

[0096] in, Indicates the energy release phase The actual falling speed of the weight at any given moment. Indicates the drum radius, This indicates the real-time rotational speed of the drum, as collected by the speed sensor. Represents pi (π). Indicates the energy release phase The acceleration of the falling weight at any given moment express The real-time tension borne by the steel wire rope that suspends the heavy object. Indicates the total mass of the object. Represents gravitational acceleration. express Real-time braking damping force at any given moment.

[0097] Furthermore, all collected signals are sent to the PLC controller in real time to form a four-closed-loop input of the actual falling speed of the heavy object, the falling acceleration of the heavy object, the falling suspension tension, and the hydraulic pressure, providing reliable data support for subsequent coordinated braking adjustment and energy recovery.

[0098] It should be noted that a normally closed mechanical brake refers to a mechanical braking device used for locking heavy objects and emergency braking. The "normally closed" nature of the normally closed mechanical brake is its core characteristic; without a control command, the brake remains in a "clamped" state and can only release after receiving a PLC control command. In this embodiment of the invention, the normally closed mechanical brake acts directly on the drum, and its core function fully serves the system's braking and locking requirements, in the following order: the normally closed mechanical brake is in a normally closed clamped state to prevent accidental movement of the heavy object; receiving a graded release command from the PLC controller, it gradually unlocks, allowing the heavy object to fall smoothly; receiving a command from the PLC controller, it quickly clamps the drum within 0.2 seconds, providing rigid locking force to ensure the heavy object remains completely stationary and does not slide down; as a backup safety braking device, it can be independently triggered to achieve an emergency stop when the system malfunctions.

[0099] In step 103, with uniform descent as the goal, the difference in falling speed is determined using the following formula based on the target falling speed and the actual falling speed of the object:

[0100] (3-1)

[0101] When the difference in falling speed is not zero, the main braking unit and the cooperative braking unit are adjusted in a coordinated manner. According to the above steps, the main braking unit and the cooperative braking unit distribute the equivalent braking force of the secondary braking in a 50 / 50 ratio.

[0102] Before introducing the coordinated adjustment of the main braking unit and the auxiliary braking unit, it is necessary to first use mathematical formulas to accurately describe the braking force calculation method, distribution rules and coordination logic of the magnetic powder braking and hydraulic braking parts.

[0103] Specifically, the core prerequisite for a heavy object to fall at a constant speed is that the net force acting on it is zero; otherwise, velocity fluctuations will occur, failing to meet the power stability requirements of grid-connected energy release. Based on this, the following formula must be satisfied for a heavy object to fall at a constant speed:

[0104] (3-2)

[0105] in, Indicates the total mass of the object. Indicates air damping force. Indicates mechanical friction resistance. This indicates the equivalent braking force of the second-stage braking system.

[0106] In practical applications, the total mass of the object is the downward driving force, which is a constant value; the air damping force is a passive resistance that varies with speed; the mechanical friction force is a constant resistance determined by the system's mechanical structure; and the secondary braking equivalent force is an upward resistance used to balance gravity and achieve uniform descent of the object.

[0107] For traditional vertical shaft gravity energy storage systems, when the system releases energy (i.e., during the energy release phase), the weight falls downwards. Taking the upward direction of the weight as positive, the direction of gravity is opposite to the positive direction, resulting in a negative force. The energy storage blocks do work based on their own weight, and must overcome air resistance, pulley system friction, and generator traction during operation. During the energy release phase, the generator traction force, load torque, and traction power can be determined using the following formulas.

[0108] (3-3)

[0109] (3-4)

[0110] (3-5)

[0111] in, This indicates the generator's traction force during the energy release phase. This indicates the load torque during the energy release phase. Energy release phase Generator traction power at all times Indicates the energy release phase The actual falling speed of the weight at any given moment.

[0112] In the above formula, It is an upward force, opposite to the direction of the falling weight, used to cooperate with the braking force to achieve uniform speed, and at the same time converts gravitational potential energy into electrical energy; Acting on the drum shaft, it reflects the effect of the generator's traction force on the shaft, and works in coordination with the secondary braking torque to ensure stable operation of the shaft system; Real-time reflection of the released energy is a core parameter for determining whether the power is stable and grid-connected.

[0113] The above formula is essentially the same as the core force balance formula, except that it represents the secondary coordinated total braking force. Replaced generator traction It constitutes the total upward resistance, ensuring that the heavy object falls at a uniform speed, and at the same time provides the calculation basis for subsequent speed closed-loop regulation and power monitoring. It is the key connection between the secondary braking model and the energy conversion grid-connected unit.

[0114] The secondary coordinated braking force is provided by both magnetic powder braking and hydraulic braking, and their relationship is as follows:

[0115] (3-6)

[0116] in, This indicates the equivalent braking force of hydraulic braking. Indicates the equivalent braking force of mechanical braking. This indicates the equivalent braking force of the second-stage braking system.

[0117] In this embodiment of the invention, the power distribution between the main braking unit and the cooperative braking unit is such that each accounts for 50% of the equivalent braking force of the secondary braking, satisfying the following formula:

[0118] (3-7)

[0119] (3-8)

[0120] Specifically, the magnetic powder brake, as the basic braking unit of the two-stage coordinated braking system, has the characteristics of stable output torque and fast response speed. It mainly bears 50% of the total braking force and provides basic stable braking damping for the system.

[0121] The output torque of a magnetic particle brake is linearly proportional to the excitation current, which can be expressed by the following formula:

[0122] (3-9)

[0123] in, This indicates the braking torque of the magnetic powder brake. This indicates the torque coefficient of the magnetic powder brake. It represents the excitation current, which is adjustable and used to control the equivalent braking force of mechanical braking.

[0124] To maintain consistency with the overall system stress analysis, the shaft torque output by the magnetic powder brake needs to be converted into an equivalent braking force in the direction of the wire rope, i.e., converted into an equivalent mechanical braking force, which is expressed by the following formula:

[0125] (3-10)

[0126] in, Indicates the equivalent braking force of mechanical braking. Indicates the drum radius, This indicates the torque coefficient of the magnetic powder brake. Indicates the radius of the roll.

[0127] As the main regulating unit of the two-stage coordinated braking system, the magnetic powder brake also undertakes the energy recovery function and is responsible for the other 50% of the total braking force. It is the core unit for achieving fine speed regulation and ensuring stable energy release power.

[0128] Specifically, hydraulic throttle braking, as the basic braking unit of the secondary coordinated braking system, provides a basic and stable braking force for the gravity energy storage system. It does not participate in the fine adjustment of speed, but is only responsible for stably bearing 50% of the total braking force, thus laying the foundation for the fine speed regulation of hydraulic braking.

[0129] In this embodiment of the invention, the hydraulic motor is used for passive braking, acting as a pump. The braking torque of the hydraulic motor is determined by the pressure difference across the throttle valve, and is calculated using the following formula:

[0130] (3-11)

[0131] in, Indicates the hydraulic braking torque. This represents a constant related to the displacement of the hydraulic motor. This indicates the pressure difference across the throttle valve. This indicates the mechanical efficiency of the hydraulic motor.

[0132] To maintain consistency with the overall system stress analysis, the hydraulic braking torque needs to be converted into an equivalent braking force in the direction of the wire rope. The hydraulic braking force is determined using the following formula:

[0133] (3-12)

[0134] in, This indicates the equivalent braking force of hydraulic braking. Indicates the radius of the roll.

[0135] In this embodiment of the invention, the change in the opening area of ​​the throttle valve directly affects the pressure difference before and after it, thereby adjusting the hydraulic braking force. The relationship between the pressure drop and flow rate of the throttle valve is determined by the following formula:

[0136] (3-13)

[0137] in, This indicates the effective opening area of ​​the throttle valve. Indicates the flow coefficient. Indicates the density of hydraulic oil. This indicates the hydraulic flow rate.

[0138] It should be noted that in the above formula, the smaller the opening of the throttle valve, the greater the resistance to hydraulic oil flow; the greater the pressure difference across the throttle valve, the greater the hydraulic braking force.

[0139] The rotational speed of the hydraulic motor is indirectly determined by the falling speed of the load, and the two are related through flow rate, specifically:

[0140] (3-14)

[0141] (3-15)

[0142] in, Indicates the displacement of the hydraulic motor. Indicates the drum speed. This represents the target velocity of the weight falling at a constant speed during the energy release phase.

[0143] As the main regulating unit of the secondary coordinated braking system, the hydraulic throttle braking can adjust the opening area of ​​the throttle valve through the PLC controller to change the hydraulic braking force and achieve fine adjustment of the falling speed of the heavy object; when the hydraulic motor is passively running, it can convert the braking mechanical energy into hydraulic energy, providing a basis for subsequent energy recovery; it acts synchronously with the magnetic powder braking, always maintaining a 50% braking force share to ensure the stability of the total braking force.

[0144] In this embodiment of the invention, the weight is a steel cube with very little air damping, which is negligible in engineering.

[0145] The air damping force is proportional to the square of the actual falling velocity of the object, and it is determined by the following formula:

[0146] (3-16)

[0147] in, Indicates air density, Indicates the drag coefficient. Indicates the windward area of ​​a heavy object. This indicates the actual falling speed of the object.

[0148] In step 103, when the falling speed difference is not equal to zero, the main braking unit and the cooperative braking unit are coordinated and adjusted, and the main braking unit and the cooperative braking unit distribute the secondary braking equivalent braking force in a 50 / 50 ratio.

[0149] In the implementation of this invention, the energy release stage is based on the force balance formula of uniform falling, combined with real-time speed closed-loop adjustment, so that the heavy object can fall at a constant speed with zero speed deviation.

[0150] First, the gravity energy storage system must meet the core equilibrium condition: the total weight of the object is equal to the sum of the air damping force, the mechanical friction resistance, and the secondary coordinated total braking force, i.e., satisfying formula (3-2). Only when this equation is satisfied can the object fall at a constant speed. Among these forces, gravity, mechanical friction resistance, and air damping force are basically constant, while the total braking force is the only parameter that can be actively controlled. Therefore, the total braking force must be strictly equal to "gravity minus air resistance minus friction resistance," which is a hard constraint for all adjustments.

[0151] Since the main braking unit is magnetic powder braking and the auxiliary braking unit is hydraulic braking, the total braking force consists of two parts: magnetic powder braking and hydraulic braking. The gravity energy storage system stipulates that the two are allocated in a fixed ratio of 1:1, each bearing half of the total braking force. This ratio cannot be changed arbitrarily.

[0152] During operation, the speed closed-loop control compares the target falling speed and the actual falling speed of the load in real time to calculate the speed difference. When the actual speed is faster than the target speed, it indicates that the total braking force is too small and does not meet the balance formula. In this case, the excitation current of the magnetic powder brake is increased, and the opening degree of the throttle valve is decreased. When the actual speed is slower than the target speed, it indicates that the total braking force is too large and disrupts the balance. In this case, the excitation current of the magnetic powder brake is decreased, and the opening degree of the throttle valve is increased.

[0153] Specifically, the excitation current of the magnetic powder brake is adjusted according to the speed deviation using a PID algorithm, thereby changing the magnitude of the magnetic powder braking force to ensure that it always maintains 50% of the total braking force.

[0154] In this embodiment of the invention, the magnetic powder braking force is controlled by the excitation current and can be determined by the following formula:

[0155] (3-17)

[0156] PID output excitation current

[0157] (3-18)

[0158] in, express The excitation current of the magnetic powder brake at all times, This represents the PID proportional coefficient. Represents the integral coefficient of the PID controller. Represents the PID differential coefficients.

[0159] In practical applications, when the falling velocity difference is less than zero, the excitation current can be increased. This improves the braking force of magnetic powder. Correspondingly, when the falling velocity difference is greater than zero, the excitation current can be reduced. This reduces the braking force of the magnetic powder. However, in this process, it is necessary to control the magnetic powder braking force. It cannot exceed 50% of the active braking force.

[0160] Furthermore, the hydraulic braking force is supplied by the throttle valve opening. The effective opening area of ​​the throttle valve is determined by the following formula:

[0161] (3-19)

[0162] in, express The effective opening area of ​​the throttle valve at any given time. This represents the initial opening area (m²) of the throttle valve. This represents the opening adjustment coefficient, used to match the coordination ratio of magnetic powder braking and hydraulic braking.

[0163] In practical applications, increase the braking force of magnetic powder. Reduce the effective opening area of ​​the throttle valve This can increase the hydraulic throttling braking force. Accordingly, reduce the magnetic powder braking force. Increase the effective opening area of ​​the throttle valve This can reduce the hydraulic throttling braking force. However, during this process, it is necessary to control the hydraulic braking force. It cannot exceed 50% of the active braking force.

[0164] In the aforementioned process, either increasing the excitation current or decreasing the throttle valve opening can increase resistance and thus improve braking force; conversely, decreasing the excitation current and increasing the throttle valve opening can decrease resistance and thus reduce braking force. During this process, mechanical braking and hydraulic braking are adjusted synchronously, resulting in a smooth change in total braking force.

[0165] In this embodiment of the invention, the two-stage coordinated braking uses the uniform force balance formula as the overall constraint, and the falling speed difference is calculated in real time by the speed closed loop. The magnetic powder brake is adjusted according to PID and bears 50% of the total braking force; the hydraulic brake is adjusted synchronously and bears 50% of the total braking force; the air damping only assists in correcting the air resistance; the three work together to make the total braking force strictly equal to the value required by the balance formula, and finally achieve a falling speed difference of zero, uniform falling of the heavy object, and stable power grid connection.

[0166] In step 103, when the falling weight meets the required pressure conditions, the hydraulic braking unit converts the braking mechanical energy generated during the falling weight into hydraulic energy and stores it in the accumulator.

[0167] In this embodiment of the invention, energy recovery is a complete process model that converts the braking mechanical energy generated during the fall of a heavy object into hydraulic energy through a hydraulic system and stores it in an accumulator before supplying it to auxiliary equipment. It includes three parts: real-time recovered power, total recovered energy, and overall recovery efficiency.

[0168] Specifically, the falling weight causes the hydraulic motor to passively operate in pump mode, converting the braking mechanical energy into the pressure energy of the hydraulic oil; the high-pressure oil is stored in the accumulator through the throttle valve and pipeline.

[0169] Specifically, the PLC controller controls the hydraulic braking unit to enter the energy recovery mode, and the hydraulic motor passively operates in pump mode, starting to convert braking mechanical energy into hydraulic energy.

[0170] In practical applications, the conversion of mechanical braking energy into usable hydraulic energy involves five stages of loss: hydraulic pump, pipeline, valve group, accumulator, and throttling braking. Each stage has losses, and multiplying them together gives the total efficiency that the system can truly recover. This efficiency can be expressed by the following formula: the efficiency of the entire process of converting hydraulic energy from braking mechanical energy into usable energy in the accumulator.

[0171] (3-21)

[0172] in: This indicates the overall efficiency of hydraulic energy recovery. Indicates the efficiency of the hydraulic motor (pump operating condition). Indicates the efficiency of friction loss along the pipeline. Indicates valve assembly efficiency. This indicates the accumulator's liquid filling efficiency. This represents the effective recovery coefficient of throttling braking.

[0173] Furthermore, when the heavy object falls and the hydraulic braking pressure is sufficient, the braking energy power recovered by the main braking unit in real time is stored in the accumulator. During this process, the hydraulic braking recovery power can be determined using the following formula:

[0174] (3-22)

[0175] in, Indicates the regenerative braking power. This indicates the actual falling speed of the object.

[0176] Furthermore, it can be determined using the following formula. Real-time regenerative braking power recovery: (3-23)

[0177] in, express Real-time energy recovery power at any moment express Real-time pressure of the hydraulic system express Real-time flow rate of the hydraulic system This indicates the energy recovery efficiency of the hydraulic system.

[0178] In practical applications, Determined by the pressure difference across the throttle valve, and related to the hydraulic braking force. Directly related; Determined by the drum speed and hydraulic motor displacement, and the actual falling speed of the load. Directly related; It represents the overall energy recovery efficiency of the hydraulic system, including all losses from pumps, pipelines, valve groups, and accumulators; That is, the rate at which braking mechanical energy is converted into usable hydraulic energy.

[0179] Furthermore, the real-time power recovery will be calculated from the start of energy recovery. By the end time Integrating the energy yields the total energy recovered during the entire energy release phase, expressed by the following formula:

[0180] (3-24)

[0181] in, This represents the total energy recovered during the energy release phase. express Real-time energy recovery power at any moment Indicates the start time of energy recovery. This indicates the point at which energy recovery ends.

[0182] In this embodiment of the invention, the recovered energy is used to power PLC controllers, sensors, hydraulic valves, etc.

[0183] In step 104, when the sensing unit determines that the remaining travel of the heavy object is less than a preset threshold, it controls the main braking unit and the cooperative braking unit to perform multi-stage deceleration cooperative braking so that the heavy object decelerates smoothly.

[0184] Specifically, when the displacement sensor detects that the remaining falling stroke of the heavy object is ≤ 5% to 10% of the total stroke, the gravity energy storage system enters the multi-stage deceleration and coordinated braking stage. The PLC controller gradually increases the damping force of the main braking unit and the coordinated braking unit according to the preset deceleration curve.

[0185] In this embodiment of the invention, the multi-stage deceleration braking is divided into three stages, which gradually reduce the falling speed of the heavy object to 80%, 50%, and 20% of the target uniform speed value, and finally to 0. The two-stage braking units always maintain a 50%:50% ratio to synchronously increase the damping, taking into account both deceleration smoothness and energy recovery efficiency.

[0186] Specifically, the PLC controller gradually increases the braking force, increases the excitation current of the magnetic powder brake, and improves the mechanical braking torque; it also closes the throttle valve opening to increase the hydraulic braking torque and achieve hydraulic coordinated braking.

[0187] During this stage, the falling speed of the object can be determined using the falling formula:

[0188] (4)

[0189] in, Indicates the energy release phase The actual falling speed of the weight at any given moment. This represents the target velocity of the weight falling at a constant speed during the energy release phase. Indicates the acceleration during the deceleration and braking period. Indicates the duration of deceleration.

[0190] As the falling speed of the object decreases steadily from the uniform target value, the gravity energy storage system adjusts the braking damping in real time, ensuring that the actual falling speed of the object strictly tracks the target speed, and ensuring that it drops to 0 without impact or slippage.

[0191] In step 105, when it is determined that the actual falling speed of the heavy object is zero, a synchronous timing brake command is sent so that the normally closed mechanical brake tightens the drum to achieve rigid locking, the main braking unit maintains the excitation current and torque, the cooperative braking unit stops, the oil tank stops releasing oil and stops supplying hydraulic energy to the accumulator.

[0192] When the PLC controller determines in real-time that the actual falling speed of the load is zero, it immediately issues a synchronous timing brake command. The normally closed mechanical brake quickly clamps the drum, achieving mechanical rigid locking; the main braking unit maintains the excitation current and braking torque output, maintains a stable damping torque, and, in conjunction with the braking unit, stops the braking pressure and simultaneously stops supplying hydraulic energy to the accumulator, entering a static pressure-holding mode. The synchronized operation and redundant braking of these three components ensure that the load remains completely stationary without slippage, rebound, or impact, achieving safe and reliable shutdown and locking.

[0193] It should be noted that in steps 101-105 above, if there are no fault or lockout protection signals, the safety braking function will be automatically activated and enter the speed over-limit standby trigger state. When the real-time speed exceeds the maximum permissible speed, the mechanical brake will be triggered immediately, and the braking force must be greater than the total weight of the system to achieve fully reliable braking.

[0194] In this embodiment of the invention, the safety braking trigger condition satisfies the following formula:

[0195] (5-1)

[0196] Furthermore, the braking force of the holding brake is determined by the following formula:

[0197] (5-2)

[0198] (5-3)

[0199] in, This indicates the brake activation signal. This indicates the maximum safe speed set by the system. This indicates the braking force output by the holding brake. This represents the coefficient of friction of the brake friction pair. This indicates the normal positive pressure applied to the brake wheel by the holding brake.

[0200] In practical applications, when the falling speed of a heavy object exceeds the maximum safe speed set by the system, the system determines it to be an overspeed dangerous condition and immediately sets the tripping device. This triggers the mechanical brake for emergency braking. To ensure braking safety, the braking force must be greater than the weight of the object, ensuring that the frictional force output by the brake is greater than the total weight of the object, thus achieving complete braking and rigid locking.

[0201] To more clearly illustrate the gravity energy storage system cooperative braking control method provided in the embodiments of the present invention, the energy recovery and release efficiency based on this method will be explained in detail below.

[0202] Specifically, this embodiment is based on a vertical shaft gravity energy storage system, combined with a two-stage coordinated braking control method and an energy recovery and release efficiency calculation model. The core parameters are as follows:

[0203] Total mass of the load (including the cage): Gravitational acceleration: The speed at which the weight is lowered at a constant speed: Equivalent braking force of hydraulic braking: Hydraulic energy recovery efficiency: Total power released by gravity: Generator output power: Total system power loss: .

[0204] According to the core formula for real-time energy recovery power Substitute the above parameters , , The real-time energy recovery power can be obtained as follows: .

[0205] Based on the total amount of regenerative braking energy, the continuous stable recovery time is taken. The total energy recovered is determined by the following formula: Substitute parameters: .

[0206] Furthermore, the grid-connected active power is obtained by subtracting the total system losses from the generator output power, specifically determined by the following formula: Substitute the parameters: .

[0207] The system energy release efficiency is the ratio of the effective grid-connected electrical energy to the total energy released by gravity, specifically: Substitute the parameters: %.

[0208] In summary, this invention provides a cooperative braking control method for a gravity energy storage system. This method ensures system stability and controllability during startup by establishing a preset braking torque and performing a self-check, avoiding speed shocks and loss of control risks during the initial descent of the load. A staged brake release method ensures smooth start-up of the load, and real-time acquisition of speed, acceleration, and suspension tension signals provides reliable data support for precise control. With a speed closed-loop as the core, the braking force is distributed equally between the main braking unit and the cooperative braking unit, quickly smoothing descent speed fluctuations and achieving uniform descent of the load, ensuring stable energy release output and meeting grid connection requirements. During the descent to meet pressure requirements, hydraulic energy recovery is automatically initiated, converting braking mechanical energy into hydraulic energy for storage, improving the overall energy efficiency of the system. Multi-stage deceleration and cooperative braking achieve smooth deceleration of the load, avoiding shutdown shocks; synchronous timing brake locking achieves rigid positioning, improving system operational safety and stability. The entire process is automated, requiring no manual intervention, and the control logic is simple and reliable, effectively improving the safety, stability, and energy utilization rate of the gravity energy storage system's energy release process.

[0209] Based on the same inventive concept, this invention provides a gravity energy storage system cooperative braking control device. Since the principle of this device in solving the technical problem is similar to that of the gravity energy storage system cooperative braking control method, the implementation of this device can refer to the implementation of the method, and the repeated parts will not be described again.

[0210] like Figure 3 As shown, the device includes an initialization unit 301, a data acquisition unit 302, a secondary braking modulation unit 303, a multi-level coordination unit 304, and a stop unit 305.

[0211] Initialization unit 301 is used to receive the energy release and grid connection command, and the main braking unit, cooperative braking unit and sensing unit perform preset braking torque establishment and status self-check;

[0212] The acquisition unit 302 is used to send a step-by-step release command to the normally closed mechanical brake so that the heavy object can start to fall under its own weight, and to acquire the actual falling speed, falling acceleration and falling suspension tension of the heavy object;

[0213] The secondary braking modulation unit 303 is used to determine the difference in falling speed based on the target speed of the falling object and the actual falling speed, with the goal of uniform falling speed. When the difference in falling speed is not equal to zero, the main braking unit and the cooperative braking unit are coordinated and adjusted. The main braking unit and the cooperative braking unit distribute the equivalent braking force of the secondary braking in a 50 / 50 ratio. When it is determined that the falling object is uniform and the pressure of the main braking unit is greater than a set value, the main braking unit is controlled to convert the braking mechanical energy generated during the falling of the object into hydraulic energy and send it to the accumulator.

[0214] The multi-level coordination unit 304 is used to control the main braking unit and the coordination braking unit to perform multi-level deceleration coordination braking when the sensing unit determines that the remaining stroke of the heavy object is less than a preset threshold, so as to make the heavy object decelerate smoothly.

[0215] The stop unit 305 is used to send a synchronous timing brake command when it is determined that the actual falling speed of the heavy object is zero, so that the normally closed mechanical brake tightens the drum to achieve rigid locking, the main braking unit maintains the excitation current and torque, the cooperative braking unit maintains the braking pressure and stops sending hydraulic pressure to the accumulator.

[0216] It should be understood that the units included in the above-mentioned gravity energy storage system coordinated braking control device are only logically divided according to the functions implemented by the device. In practical applications, the above-mentioned units can be superimposed or split. Furthermore, the functions implemented by the gravity energy storage system coordinated braking control device provided in this embodiment correspond one-to-one with the gravity energy storage system coordinated braking control method provided in the above-mentioned embodiments. The more detailed processing flow implemented by this device has been described in detail in the above-mentioned method embodiment one, and will not be described in detail here.

[0217] Another embodiment of the present invention provides a computer device, the computer device including: a processor and a scene database; the scene database is used to store computer program code, the computer program code including computer instructions; when the processor executes the computer instructions, the electronic device executes each step of the gravity energy storage system cooperative braking control method shown in the above method embodiment.

[0218] Another embodiment of the present invention provides a computer-readable storage medium storing computer instructions that, when executed on a computer device, cause the computer device to perform the various steps of the gravity energy storage system cooperative braking control method shown in the above method embodiment.

[0219] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for coordinated braking control of a gravity energy storage system, characterized in that, include: Upon receiving the energy release and grid connection command, the main braking unit, the cooperative braking unit, and the sensing unit perform preset braking torque establishment and status self-check; Send a step-by-step release command to the normally closed mechanical brake to make the heavy object start to fall under its own weight, and obtain the actual falling speed, falling acceleration and falling suspension tension of the heavy object; With the goal of uniform descent, the difference in descent speed is determined based on the target descent speed and the actual descent speed. When the difference in descent speed is not equal to zero, the main braking unit and the cooperative braking unit are coordinated and adjusted. The main braking unit and the cooperative braking unit distribute the total braking force in a 50 / 50 ratio. When it is determined that the object is falling at a uniform speed and the pressure of the hydraulic system included in the main braking unit is greater than a set value, the cooperative braking unit is controlled to convert the braking mechanical energy generated during the descent of the object into hydraulic energy and send it to the accumulator. When the sensing unit determines that the remaining stroke of the heavy object is less than a preset threshold, it controls the main braking unit and the cooperative braking unit to perform multi-stage deceleration cooperative braking so that the heavy object decelerates smoothly. When the actual falling speed of the heavy object is determined to be zero, a synchronous timing brake command is sent so that the normally closed mechanical brake tightens the drum to achieve rigid locking, the main braking unit maintains the excitation current and torque, the cooperative braking unit maintains the braking pressure and stops supplying hydraulic energy to the accumulator.

2. The method as described in claim 1, characterized in that, The actual falling speed of the weight is determined by the following formula: The falling acceleration is determined by the following formula: The descent suspension tension is the real-time tension borne by the steel wire rope suspending the weight, and is determined by the following formula: in, Indicates the energy release phase The actual falling speed of the weight at any given moment. Indicates the drum radius, This indicates the real-time rotational speed of the drum, as collected by the speed sensor. Represents pi (π). Indicates the energy release phase The acceleration of the falling weight at any given moment express The real-time tension borne by the steel wire rope that suspends the heavy object. Indicates the total mass of the object. Represents gravitational acceleration. express Real-time braking damping force at any given moment.

3. The method as described in claim 1, characterized in that, The difference in falling speeds is determined by the following formula: The coordinated adjustment of the base braking force and the pre-tensioned braking force specifically includes: The main braking unit is a magnetic powder brake, and the cooperative braking unit is a hydraulic brake; When the difference in falling speed is greater than zero, increase the excitation current of the magnetic powder brake and decrease the opening of the throttle valve to ensure that the adjustment ratio of the hydraulic brake and the magnetic powder brake each accounts for 50% of the total braking force; Alternatively, when the difference in falling speed is less than zero, reduce the excitation current of the magnetic powder brake and increase the opening of the throttle valve to ensure that the adjustment ratio of the hydraulic brake and the magnetic powder brake each accounts for 50% of the total braking force; in, express The difference in falling speed at any given moment, Indicates the energy release phase The actual falling speed of the weight at any given moment. This represents the target velocity of the weight falling at a constant speed during the energy release phase.

4. The method as described in claim 3, characterized in that, The excitation current of the magnetic powder brake is determined by the following formula: The hydraulic braking force is determined by the following formula: in, express Magnetic powder braking force at all times, This indicates the torque coefficient of the magnetic powder brake. express The excitation current of the magnetic powder brake at all times Indicates the drum radius, Indicates the PID proportional gain. Indicates the integral gain of the PID controller. This represents the differential gain of the PID controller. express The difference in falling speed at any given moment, Indicates the hydraulic braking load torque. This represents a constant related to the displacement of the hydraulic motor. This indicates the pressure difference across the throttle valve. Indicates the mechanical efficiency of a hydraulic motor. Indicates hydraulic flow rate. Indicates the flow coefficient. This indicates the effective opening area of ​​the throttle valve. Indicates the density of hydraulic oil. Indicates the displacement of the hydraulic motor. Indicates the drum speed. This represents the target velocity of the weight falling at a constant speed during the energy release phase. Represents pi (π). Indicates the hydraulic braking load torque. express The effective opening area of ​​the throttle valve at any given time. This represents the initial opening area of ​​the throttle valve. This represents the opening adjustment coefficient, used to match the coordination ratio of magnetic powder braking and hydraulic braking.

5. The method as described in claim 1, characterized in that, When the cooperative braking unit converts the braking mechanical energy generated during the fall of the heavy object into hydraulic energy and sends it to the accumulator, the real-time recovered power is determined by the following formula: The total recovered energy is determined by the following formula: in, express Real-time energy recovery power at any moment express Real-time pressure of the hydraulic system express Real-time flow rate of the hydraulic system Indicates the energy recovery efficiency of the hydraulic system. This represents the total energy recovered during the energy release phase. express Real-time energy recovery power at any moment Indicates the start time of energy recovery. This indicates the point at which energy recovery ends.

6. The method as described in claim 1, characterized in that, When the sensing unit determines that the remaining travel distance of the weight is less than a preset threshold, the actual falling speed of the weight is determined by the following formula: The multi-stage deceleration braking period is divided into three stages, which successively reduce the falling speed of the heavy object to 80%, 50%, and 20% of the target falling speed of the heavy object, until the falling speed of the heavy object is 0. in, Indicates the energy release phase The actual falling speed of the weight at any given moment. This represents the target velocity of the weight falling at a constant speed during the energy release phase. Indicates the acceleration during the deceleration and braking period. Indicates the duration of deceleration.

7. The method as described in claim 1, characterized in that, When it is determined that the actual falling speed of the heavy object is zero, a synchronous timing brake command is sent, specifically including: The synchronous timing brake commands include: commands to stop the braking pressure of the cooperative braking unit and stop supplying hydraulic energy to the accumulator, commands to maintain the excitation current and torque, and commands to quickly clamp the drum.

8. The method as described in claim 1, characterized in that, The method further includes: Upon receiving the energy storage command, the main braking unit and the cooperative braking unit synchronously release the brakes, and the lifting motor drives the heavy object to rise. The actual rising speed, rising acceleration, and suspension tension of the heavy object are obtained, and the main braking unit and the cooperative braking unit are coordinated and adjusted according to the difference between the rising and falling speeds. When it is determined that the heavy object has reached the target height, the main braking unit, the cooperative braking unit and the mechanical brake engage the brakes in a synchronized sequence. The actual lift rate is determined by the following formula: The acceleration due to ascent is determined by the following formula: Suspension tension is determined by the following formula: in, Indicates energy storage stage The actual rising speed of the weight at any given moment. Indicates the drum radius, This indicates the real-time rotational speed of the drum, as collected by the speed sensor. Represents pi (π). Indicates energy storage stage The upward acceleration of the weight at any given moment. express The real-time tension borne by the steel wire rope that suspends the heavy object. Indicates the total mass of the object. Represents gravitational acceleration. express Real-time braking damping force at any moment This represents the frictional resistance experienced by the object as it rises. This indicates the air resistance encountered by the heavy object during its ascent.

9. A gravity energy storage system coordinated braking control device, characterized in that, include: The initialization unit is used to receive the energy release and grid connection command, and the main braking unit, the cooperative braking unit, and the sensing unit perform preset braking torque establishment and status self-check. The data acquisition unit is used to send a step-by-step release command to the normally closed mechanical brake so that the heavy object can start to fall under its own gravity, and to acquire the actual falling speed, falling acceleration and falling suspension tension of the heavy object. The secondary braking modulation unit is used to determine the difference in falling speed based on the target speed of the falling object and the actual falling speed, with the goal of uniform descent. When the difference in falling speed is not equal to zero, the main braking unit and the cooperative braking unit are coordinated and adjusted. The main braking unit and the cooperative braking unit distribute the equivalent braking force of the secondary braking in a 50 / 50 ratio. When it is determined that the falling object is uniform and the pressure of the main braking unit is greater than a set value, the main braking unit is controlled to convert the braking mechanical energy generated during the falling object into hydraulic energy and send it to the accumulator. A multi-level coordination unit is used to control the main braking unit and the coordination braking unit to perform multi-level deceleration coordination braking when the sensing unit determines that the remaining stroke of the heavy object is less than a preset threshold, so as to make the heavy object decelerate smoothly. The stopping unit is used to send a synchronous timing brake command when it is determined that the actual falling speed of the heavy object is zero, so that the normally closed mechanical brake tightens the drum to achieve rigid locking, the cooperative braking unit stops the braking pressure and stops the supply of hydraulic energy to the accumulator, and the main braking unit maintains the excitation current and torque.

10. A computer device, characterized in that, The computer device includes a memory and a processor. The memory stores a computer program, which, when executed by the processor, causes the processor to perform the coordinated braking control method for the gravity energy storage system as described in any one of claims 1-8.

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