Vertical gravity energy storage system control method based on doubly-fed motor

Abstract

A vertical gravity energy storage system control method based on a doubly-fed motor comprises the following steps: analyzing physical characteristics and a mathematical analysis model of a weight block of a gravity energy storage system in ascending and descending processes, and establishing a weight block speed given value function; according to the structure of the gravity energy storage system and the speed given value of the weight block, the rotating speed given value of the doubly-fed motor is calculated; according to the given rotating speed and the given reactive power of the doubly-fed motor, rotor side reference voltage is output to the doubly-fed motor, and the reference voltage is used for adjusting the rotating speed and the reactive power of the doubly-fed motor. The control algorithm is used for controlling the movement speed and the power generation power of the weight block, and the operation stability of the double-fed motor of the gravity energy storage system during frequent switching of various working conditions is improved.

Description

Technical Field

[0001] The invention relates to the technical field of gravity energy storage, and in particular to a control method for a vertical gravity energy storage system based on a double-fed motor. Background Art

[0002] Traditional pumped storage is the most widely used large-scale energy storage technology in the power system. However, due to the geographical conditions of water resources, large-scale development is limited, and it is difficult to meet the diverse application scenarios of new power systems in terms of power response time and efficiency. Gravity energy storage technology based on solid weights is expected to become one of the important energy storage technologies in water-scarce areas in the future, with its advantages of being independent of water resources, flexible in site selection, and high in efficiency, and can well meet the demand for energy storage technology for renewable energy power grid connection.

[0003] Gravity energy storage is mainly divided into two categories: one is the slope gravity energy storage system, which covers mountain rail vehicle energy storage, mountain gravity energy storage, etc.; the other is the vertical gravity energy storage system, including energy storage tower type, vertical matrix type, underground shaft energy storage, piston water pump energy storage, etc. The slope gravity energy storage system is suitable for energy storage in mountainous areas, with high site selection requirements, and the conversion efficiency and comprehensive benefits are not ideal. The energy storage tower type and vertical matrix type in the vertical gravity energy storage system have no geographical restrictions and are highly feasible for large-scale promotion. Although the key technologies of vertical gravity energy storage system's technical vertical lifting, horizontal transfer and automatic connection, as well as core electromechanical equipment such as generator motor and grid connection control have been elaborated and discussed; there are still many technical problems to be solved in terms of rapid lifting and transfer of heavy loads, heavy object start-stop and switching process control, grid connection control and energy efficiency improvement, especially the problem of low energy conversion efficiency of gravity energy storage system when the motor is frequently started and stopped and rise / fall, and the frequent switching between the electric / generating states.

[0004] The technical differences between this application and the prior art are as follows: Technical comparison with patent CN119010116A "An economical modular gravity energy storage system operation method"; Patent CN119010116A controls the stator voltage, stator current, excitation current, etc., reduces various losses during the operation of the gravity energy storage system, and realizes the economic operation of the gravity energy storage system. The present invention uses a seven-segment s-speed curve to control the movement speed of the weight block, establishes a motion curve function of the weight block movement process, reduces the impact of the acceleration and deceleration of the weight block on the gravity energy storage system, and improves the stability of the operation of the gravity energy storage system.

[0005] Technical comparison with patent CN116505666A "A direct-drive gravity energy storage system and its optimization method"; Patent CN116505666A is a direct-drive gravity energy storage system, and the control object of the motor controller is the d-axis current on the stator side of the motor i s_d , stator side q-axis current i s_q The present invention is a control method for a gravity energy storage system with gear transmission, and establishes a motion curve function of the weight block motion process. The control object of the motor controller is the d-axis current on the motor rotor side. i rd , rotor side q-axis current i rq , improve the stability of gravity energy storage system operation.

[0006] Technical comparison with patent CN115653855A "A method for improving the efficiency of gravity energy storage power generation system"; Patent CN115653855A analyzes the energy conservation equation during the movement of the weight block in the gravity energy storage system, and improves the operating efficiency of the gravity energy storage system by adding a cable chain channel to connect the falling weight and the weight to be lifted in the system. The present invention uses a seven-segment s-speed curve to control the movement speed of the weight block, establishes a motion curve function during the movement of the weight block, reduces the impact of the acceleration and deceleration of the weight block on the gravity energy storage system, and improves the stability of the operation of the gravity energy storage system.

[0007] Technical comparison with patent CN118619055A "A vertical gravity energy storage system based on a doubly-fed generator"; Patent CN118619055A designs a vertical gravity energy storage system based on a doubly-fed motor, describes the spatial layout structure of the components of the gravity energy storage system, and analyzes the operation process of the gravity energy storage system. The present invention focuses on analyzing the operation status of the weight block under different working conditions, establishing the motion curve function of the weight block movement process, thereby reducing the impact of the acceleration and deceleration of the weight block on the gravity energy storage system and improving the stability of the operation of the gravity energy storage system.

[0008] Technical comparison with patent CN117895541A "A gravity energy storage power smoothing control method considering energy storage capacity limitation"; Patent CN117895541A compares the basic mathematical model of the gravity energy storage body to the charge state of battery energy storage, establishes a mathematical model to measure the equivalent charge state of the energy storage body, and then studies the body control strategy considering capacity limitations; adds a first-order inertia link to the synchronous machine input torque, smoothes the input / output power of the synchronous machine, and suppresses the frequency oscillation problem caused by torque jump. The present invention analyzes the operating state of the weight block under different working conditions, establishes the motion curve function of the weight block movement process, thereby reducing the impact of the acceleration and deceleration of the weight block on the gravity energy storage system, realizing the control of the speed and reactive power of the double-fed motor, and improving the stability of the operation of the gravity energy storage system.

[0009] The present invention proposes a control method for a vertical gravity energy storage system based on a doubly-fed motor. Based on the principle of gravity energy storage technology, the method establishes a mathematical model of the rising and falling process of a heavy object, uses modeling and simulation software to simulate the movement process of the heavy object, and uses a control algorithm to control the movement speed and power generation of the heavy object, thereby improving the operating stability of the doubly-fed motor of the gravity energy storage system when various working conditions are frequently switched. Summary of the invention

[0010] In view of the problem that the existing gravity energy storage system has poor system stability when the double-fed motor is frequently started and stopped and the motoring / generating states are frequently switched, the present invention proposes a control method for a vertical gravity energy storage system based on a double-fed motor to improve the operating stability of the gravity energy storage system under various working conditions.

[0011] To achieve the above object, the technical solution adopted by the present invention is: A control method for a vertical gravity energy storage system based on a doubly-fed motor comprises the following steps: S1 analyzes the physical characteristics and mathematical analytical model of the rising and falling process of the heavy object block in the gravity energy storage system, and establishes the given value function of the speed of the heavy object block; S2 calculates the given value of the speed of the doubly-fed generator according to the structure of the gravity energy storage system and the given value of the speed of the weight block; S3 outputs a rotor-side reference voltage to the doubly-fed motor according to a given speed and a given reactive power of the doubly-fed motor, wherein the reference voltage is used to adjust the speed and reactive power of the doubly-fed motor.

[0012] As a further improvement of the present invention, the control method of a vertical gravity energy storage system based on a doubly-fed motor is characterized in that: the step S1 establishes a given value function of the speed of the weight block, and the specific process is as follows: A seven-segment s-speed curve is used to control the speed of the weight, which involves physical quantities including constant acceleration. J , constant reverse jerk - J、 Maximum acceleration a max, Maximum reverse acceleration - a max , Maximum speed v max , the number of times the weight position information is recorded per second d , the total distance the weight moves h , Heavy object movement time t , weight speed v ; The first paragraph: At constant acceleration J Movement, weight speed v The expression is: ; Among them, the first period ; Second paragraph: In At maximum acceleration a max Movement, weight speed v The expression is; ; Among them, the speed of the first period of time , the second period ; The third paragraph: When the reverse acceleration is constant - J Movement, weight speed v The expression is: ; Among them, the speed of the second period , the third period ; The fourth paragraph: At maximum speed v max Sports, including h is the total distance the weight moves, and the speed of the weight v The expression is: ; Among them, the speed of the third period , the fourth period ; Paragraph 5: In When the reverse acceleration is constant - J Movement, weight speed v The expression is: ; Among them, the speed of the fourth period , the fifth period ; ; Paragraph 6: In When the maximum reverse acceleration is - a max Movement, weight speed v The expression is: ; Among them, the speed of the fifth period , the sixth period ; Paragraph 7: In At constant acceleration J Movement, weight speed v The expression is: ; Among them, the speed of the sixth period , the seventh period .

[0013] As a further improvement of the present invention, step S2 calculates and obtains the given value of the speed of the doubly-fed generator, including: According to the given value of the speed of the weight block and the drive shaft radius r , get the angular velocity of the transmission shaft , determined by the gearbox ratio k , get the motor mechanical angular velocity , and finally get the motor speed given value , the expression is as follows: ; Among them, the gearbox transmission ratio .

[0014] As a further improvement of the present invention, step S3 outputs a rotor-side reference voltage to the doubly-fed motor according to a given speed and a given reactive power of the doubly-fed motor, comprising the following steps: Step 1: Calculate the reactive power setting value of the doubly-fed generator and motor speed given value ; Step 2: Obtain the three-phase voltage of the power grid connected to the stator of the doubly-fed generator u sabc , Current i sabc , the three-phase current of the doubly-fed machine rotor connected to the converter i rabc And the motor mechanical angular velocity , obtain the stator voltage angular velocity through the phase-locked loop PLL Then integrate to get the stator flux angle , motor mechanical angular velocity Multiply by the number of pole pairs n p Get the rotor electrical angular velocity Then integrate to get the rotor flux angle , motor mechanical angular velocity Multiply by a factor Get the motor speed n ; Three-phase voltage of power grid u sabc , Current i sabc After coordinate transformation, the stator voltage in the dq coordinate system is obtained u sdq , Current i sdq , where the stator voltage u sdq Including d-axis component u sd , q-axis component u sq , stator current i sdq Including d-axis component i sd , q-axis component i sq , according to the power calculation formula, the stator active power is calculated P s , stator reactive power Q s ; Doubly-fed machine rotor three-phase current i rabc After coordinate transformation, the actual value of the rotor current in the dq coordinate system is obtained i rdq , where the actual value of the rotor current is i rdq Including d-axis component i rd , q-axis component i rq ; Step 3: Set the reactive power setting value of the doubly-fed generator , Motor speed given value and stator reactive power Q s , Motor speed n Make a difference, input the PI regulator, and output the rotor current given value in the dq coordinate system ; Step 4: Output the rotor current given value in the dq coordinate system and the actual value of the rotor current in the dq coordinate system i rdqThe result and coupling amount obtained by inputting the PI regulator Perform calculation and output the rotor voltage given value ; Step 5: Set the rotor voltage to a given value After coordinate transformation, we get Rotor voltage reference value in coordinate system , input space vector pulse width modulation SVPWM module, output three-phase PWM wave driving converter, where the converter bus voltage u dc is a constant.

[0015] As a further improvement of the present invention, in step 1, it is stipulated that the motor speed of the gravity energy storage system based on the double-fed motor is positive when the weight block rises, and the motor speed is negative when the weight block falls, and the reactive power given value of the double-fed motor is calculated. and motor speed given value , where when the weight rises, the motor speed is set to ;When the weight is lowered, the motor speed is set to .

[0016] As a further improvement of the present invention, in step 4, the actual value of the rotor current in the dq coordinate system is i rdq 、Stator voltage angular velocity , rotor electrical angular velocity , stator voltage amplitude , calculate the coupling , where the coefficient matrix A and compensation term B are: ; Among them, leakage inductance , slip speed , L r is the rotor self-inductance, L s is the stator self-inductance, L m is the maximum mutual inductance of the stator and rotor windings in the two-phase rotating coordinate system.

[0017] The advantages of the present invention are: The present invention analyzes the movement process of the weight block and establishes the relationship between the movement speed of the weight block and the motor speed; adopts a seven-segment S speed curve control method to reduce the impact of speed mutation on the gravity energy storage system and enhance the stability of the system; the gravity energy storage system adopts speed current and reactive power dual closed-loop control to achieve precise control of the speed and reactive power of the doubly fed motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a flow chart of the implementation of the control method of the vertical gravity energy storage system based on the doubly-fed generator of the present invention; Figure 2 The motion curve diagram of the weight block of the present invention; Figure 3 It is a schematic diagram of the connection of various components of the vertical gravity energy storage system based on the doubly-fed generator of the present invention; Figure 4 It is a structural block diagram of a control method of a vertical gravity energy storage system based on a doubly-fed generator according to the present invention; Figure 5 It is a schematic diagram of the calculation process of the given reactive power and speed of the double-fed motor of the gravity energy storage system of the present invention; Figure 6 It is a schematic diagram of the active power calculation and reactive power calculation process of the double-fed generator of the gravity energy storage system of the present invention; Figure 7 It is a schematic diagram of the calculation process of the dq voltage coupling amount of the doubly-fed motor rotor in the gravity energy storage system of the present invention; Figure 8 It is a simulation waveform diagram of the motor speed of the vertical gravity energy storage system based on the double-fed motor of the present invention working in the energy storage mode; Fig. 9 It is a simulation waveform diagram of reactive power of the vertical gravity energy storage system based on the doubly-fed generator of the present invention working in the energy storage mode; Fig.10 It is a simulation waveform diagram of the motor speed of the vertical gravity energy storage system based on the double-fed generator of the present invention working in the energy release mode; Fig.11 It is a simulation waveform diagram of reactive power of the vertical gravity energy storage system based on the doubly-fed generator of the present invention working in the energy release mode. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0020] The control method implementation flow chart of the vertical gravity energy storage system based on the doubly fed generator is as follows: Figure 1 As shown, the method includes: analyzing the physical characteristics and mathematical analytical model of the rising and falling process of the weight block of the gravity energy storage system, and establishing a weight block speed given value function; calculating the double-fed motor speed given value according to the gravity energy storage system structure and the weight block speed given value; according to the given speed and given reactive power of the double-fed motor, outputting a rotor-side reference voltage to the double-fed motor, wherein the reference voltage is used to adjust the speed and reactive power of the double-fed motor.

[0021] Optionally, the step of analyzing the physical characteristics and mathematical analytical model of the weight block rising and falling process of the gravity energy storage system and establishing a weight block speed given value function includes: During the operation of the gravity energy storage system, in order to reduce the impact of the acceleration and deceleration of the weight on the gravity energy storage system, a seven-segment s-speed curve is used to control the movement speed of the weight, in which the physical quantities involved include constant acceleration J Size is 4, maximum acceleration a max Size is 2, maximum speed v max The size is 4, and the number of times the position information of the weight block is recorded per second d The size is 1000, and the total distance h of the weight block movement is 68; the movement state of the weight block is obtained, as shown in Table 1; the movement curve of the weight block is as shown in Figure 2 shown.

[0022] Table 1 Movement state of the heavy block

[0023] Optionally, according to the structure of the gravity energy storage system and the given value of the speed of the weight block, the given value of the speed of the doubly-fed generator is calculated, including: The connection diagram of each component of the vertical gravity energy storage system based on the doubly fed generator is as follows: Figure 3 As shown, according to the given value of the speed of the weight block and the drive shaft radius r , get the angular velocity of the transmission shaft , determined by the gearbox ratio k , get the motor mechanical angular velocity , and finally get the motor speed given value , the expression is as follows: ; Among them, the gearbox transmission ratio .

[0024] Optionally, a structural block diagram of a control method for a vertical gravity energy storage system based on a doubly-fed motor is as follows: Figure 4 As shown, according to a given speed and a given reactive power of the doubly-fed motor, outputting a rotor-side reference voltage to the doubly-fed motor comprises the following steps: Step 1: Calculate the reactive power setting value of the doubly-fed generator and motor speed given value ; Step 2: Obtain the three-phase voltage of the power grid connected to the stator of the doubly-fed generator u sabc , Current i sabc , the three-phase current of the doubly-fed machine rotor connected to the converteri rabc And the motor mechanical angular velocity , obtain the stator voltage angular velocity through the phase-locked loop PLL Then integrate to get the stator flux angle , motor mechanical angular velocity Multiply by the number of pole pairs n p Get the rotor electrical angular velocity Then integrate to get the rotor flux angle , motor mechanical angular velocity Multiply by a factor Get the motor speed n ; Three-phase voltage of power grid u sabc , Current i sabc After coordinate transformation, the stator voltage in the dq coordinate system is obtained u sdq , Current i sdq , where the stator voltage u sdq Including d-axis component u sd , q-axis component u sq , stator current i sdq Including d-axis component i sd , q-axis component i sq , the schematic diagram of the active power calculation and reactive power calculation process of the double-fed generator of the gravity energy storage system, as shown in Figure 6 As shown, according to the power calculation formula, the stator active power is calculated P s , stator reactive power Q s ; Doubly-fed machine rotor three-phase current i rabc After coordinate transformation, the actual value of the rotor current in the dq coordinate system is obtained i rdq , where the actual value of the rotor current is i rdq Including d-axis component i rd , q-axis component i rq ; Step 3: Set the reactive power setting value of the doubly-fed generator , Motor speed given value and stator reactive power Q s , Motor speedn Make a difference, input the PI regulator, and output the rotor current given value in the dq coordinate system ; Step 4: Output the rotor current given value in the dq coordinate system and the actual value of the rotor current in the dq coordinate system i rdq The result and coupling amount obtained by inputting the PI regulator Perform calculation and output the rotor voltage given value ; Step 5: Set the rotor voltage to a given value After coordinate transformation, we get Rotor voltage reference value in coordinate system , input space vector pulse width modulation SVPWM module, output three-phase PWM wave driving converter, where the converter bus voltage u dc =1200V.

[0025] In the above step 1, the schematic diagram of the calculation process of the given reactive power and speed of the double-fed generator of the gravity energy storage system is as follows: Figure 5 As shown in the figure, it is stipulated that the motor speed of the gravity energy storage system based on the double-fed motor is positive when the weight block rises, and the motor speed is negative when the weight block falls. The reactive power given value of the double-fed motor is calculated and motor speed given value , where when the weight rises, the motor speed is set to ;When the weight is lowered, the motor speed is set to .

[0026] In the above step 4, the actual value of the rotor current in the dq coordinate system is i rdq 、Stator voltage angular velocity , rotor electrical angular velocity , stator voltage amplitude , calculate the coupling , where the coefficient matrix A and compensation term B are: ; Among them, leakage inductance , slip speed , L r is the rotor self-inductance, L s is the stator self-inductance, L m is the maximum mutual inductance of the stator and rotor windings in the two-phase rotating coordinate system.

[0027] Figure 8This is a simulation waveform of the motor speed of a vertical gravity energy storage system based on a doubly fed generator working in energy storage mode. Fig. 9 It is a simulation waveform diagram of reactive power of a vertical gravity energy storage system based on a doubly-fed generator working in energy storage mode; Fig.10 This is a simulation waveform of the motor speed of a vertical gravity energy storage system based on a doubly fed generator working in the energy release mode. Fig.11 It is a simulation waveform diagram of the reactive power of the vertical gravity energy storage system based on the doubly fed motor working in the energy release mode; the experimental results show that: the control method of the vertical gravity energy storage system based on the doubly fed motor in the present application can realize precise control of the speed (movement speed of the heavy object) and reactive power of the doubly fed motor when the gravity energy storage system works in the energy storage and energy release modes.

[0028] The above description is only a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent change made based on the technical essence of the present invention still falls within the scope of protection required by the present invention.

Claims

1. A control method for a vertical gravity energy storage system based on a doubly-fed motor, characterized in that: The following steps are involved: S1: Analyze the physical characteristics and mathematical analytical model of the rising and falling process of the heavy object in the gravity energy storage system, and establish the given value function of the speed of the heavy object; S2: According to the structure of the gravity energy storage system and the given value of the speed of the weight block, the given value of the speed of the doubly-fed generator is calculated; S3: outputting a rotor-side reference voltage to the doubly-fed motor according to a given speed and a given reactive power of the doubly-fed motor, wherein the reference voltage is used to adjust the speed and reactive power of the doubly-fed motor.

2. According to claim 1, a control method for a vertical gravity energy storage system based on a doubly-fed motor is characterized in that: The step S1 establishes a given value function of the speed of the weight block, and the specific process is as follows: A seven-segment s-speed curve is used to control the speed of the weight, which involves physical quantities including constant acceleration. J , constant reverse jerk - J、 Maximum acceleration a max , Maximum reverse acceleration - a max , Maximum speed v max , the number of times the weight position information is recorded per second d , the total distance the weight moves h , Heavy object movement time t , weight speed v ; The first paragraph: At constant acceleration J Movement, weight speed v The expression is: ； Among them, the first period ; Second paragraph: In At maximum acceleration a max Movement, weight speed v The expression is; ； Among them, the speed of the first period of time , the second period ; The third paragraph: When the reverse acceleration is constant - J Movement, weight speed v The expression is: ； Among them, the speed of the second period , the third period ; The fourth paragraph: At maximum speed v max Sports, including h is the total distance the weight moves, and the speed of the weight v The expression is: ； Among them, the speed of the third period , the fourth period ; Paragraph 5: In When the reverse acceleration is constant - J Movement, weight speed v The expression is: ； Among them, the speed of the fourth period , the fifth period ; ； Paragraph 6: In When the maximum reverse acceleration - a max Movement, weight speed v The expression is: ； Among them, the speed of the fifth period , the sixth period ; Paragraph 7: In At constant acceleration J Movement, weight speed v The expression is: ； Among them, the speed of the sixth period , the seventh period .

3. The control method of a vertical gravity energy storage system based on a doubly-fed motor according to claim 1, characterized in that: Step S2 calculates and obtains the given value of the speed of the doubly-fed generator, including: According to the given value of the speed of the weight block and the drive shaft radius r , get the angular velocity of the transmission shaft , determined by the gearbox ratio k , get the motor mechanical angular velocity , and finally get the motor speed given value , the expression is as follows: ； Among them, the gearbox transmission ratio .

4. The control method of a vertical gravity energy storage system based on a doubly-fed motor according to claim 1, characterized in that: Step S3 outputs a rotor-side reference voltage to the doubly-fed motor according to a given speed and a given reactive power of the doubly-fed motor, and includes the following steps: Step 1: Calculate the reactive power setting value of the doubly-fed generator and motor speed given value ; Step 2: Obtain the three-phase voltage of the power grid connected to the stator of the doubly-fed generator u sabc , Current i sabc , the three-phase current of the doubly-fed machine rotor connected to the converter i rabc And the motor mechanical angular velocity , obtain the stator voltage angular velocity through the phase-locked loop PLL Then integrate to get the stator flux angle , motor mechanical angular velocity Multiply by the number of pole pairs n p Get the rotor electrical angular velocity Then integrate to get the rotor flux angle , motor mechanical angular velocity Multiply by coefficient Get the motor speed n ; Three-phase voltage of power grid u sabc , Current i sabc After coordinate transformation, the stator voltage in the dq coordinate system is obtained u sdq , Current i sdq , where the stator voltage u sdq Including d-axis component u sd , q-axis component u sq , stator current i sdq Including d-axis component i sd , q-axis component i sq , according to the power calculation formula, the stator active power is calculated P s , stator reactive power Q s ; Doubly-fed machine rotor three-phase current i rabc After coordinate transformation, the actual value of the rotor current in the dq coordinate system is obtained i rdq , where the actual value of the rotor current is i rdq Including d-axis component i rd , q-axis component i rq ; Step 3: Set the reactive power setting value of the doubly-fed generator , Motor speed given value and stator reactive power Q s , Motor speed n Make a difference, input the PI regulator, and output the rotor current given value in the dq coordinate system ; Step 4: Output the rotor current given value in the dq coordinate system The actual value of the rotor current in the dq coordinate system i rdq The result and coupling amount obtained by inputting the PI regulator Perform calculation and output the rotor voltage given value ; Step 5: Set the rotor voltage to a given value After coordinate transformation, we get Rotor voltage reference value in coordinate system , input space vector pulse width modulation SVPWM module, output three-phase PWM wave driving converter, where the converter bus voltage u dc is a constant.

5. The control method of a vertical gravity energy storage system based on a doubly-fed motor according to claim 4 is characterized in that: In step 1, it is stipulated that the motor speed of the gravity energy storage system based on the doubly fed motor is positive when the weight block rises, and the motor speed is negative when the weight block falls, and the reactive power given value of the doubly fed motor is calculated. and motor speed given value , where when the weight rises, the motor speed is set to ;When the weight is lowered, the motor speed is set to .

6. A control method for a vertical gravity energy storage system based on a doubly-fed motor according to claim 4, characterized in that: In step 4, the actual value of the rotor current in the dq coordinate system is i rdq 、Stator voltage angular velocity , rotor electrical angular velocity , stator voltage amplitude , calculate the coupling , where the coefficient matrix A and compensation term B are: ； Among them, leakage inductance , slip speed , L r is the rotor self-inductance, L s is the stator self-inductance, L m is the maximum mutual inductance of the stator and rotor windings in the two-phase rotating coordinate system.

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