CN215956053U

CN215956053U - Wind turbine energy storage system and wind turbine

Info

Publication number: CN215956053U
Application number: CN202122088716.XU
Authority: CN
Inventors: 杨志千; 杨有涛
Original assignee: Beijing Goldwind Science and Creation Windpower Equipment Co Ltd
Current assignee: Beijing Goldwind Science and Creation Windpower Equipment Co Ltd
Priority date: 2021-08-31
Filing date: 2021-08-31
Publication date: 2022-03-04
Anticipated expiration: 2031-08-31

Abstract

The application discloses an energy storage system of a wind power generator set and a wind power generator set, which belong to the technical field of wind power generation. The energy storage system of the wind turbine includes: a generator, a first energy storage unit, a converter and a step-up transformer; the converter includes a connected AC/DC AC/DC converter and a DC/AC DC/AC converter The generator is connected with the AC/DC converter, the DC/AC converter is connected with the step-up transformer, and the first energy storage unit is connected with the AC/DC converter; It is used to store the electrical energy produced by the generator or release the stored electrical energy. According to the embodiments of the present application, the working reliability of the converter of the wind turbine can be improved.

Description

Energy storage system of wind generating set and wind generating set

Technical Field

The application belongs to the technical field of wind power generation, and particularly relates to an energy storage system of a wind generating set and the wind generating set.

Background

With the rapid development of science and technology, the demand of various fields on energy is gradually increased, and the application of new energy technologies such as wind power generation and the like is wider.

The wind generating set is a device capable of converting wind energy into electric energy. The wind generating set can be connected with a power grid so as to interact with the power grid. However, when a fault such as grounding occurs on the grid side and low voltage ride through is performed, the output of the wind turbine generator system is limited, which may cause the bus voltage of the converter on the side of the wind turbine generator system to increase, and reduce the reliability of the converter operation.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides a wind generating set's energy storage system and wind generating set, can improve the reliability of wind generating set's converter work.

In a first aspect, an embodiment of the present application provides an energy storage system of a wind turbine generator system, including a generator, a first energy storage unit, a converter, and a step-up transformer; the converter comprises an alternating current/direct current AC/DC converter and a direct current/alternating current DC/AC converter which are connected; the generator is connected with the AC/DC converter, the DC/AC converter is connected with the step-up transformer, and the first energy storage unit is connected with the AC/DC converter; the first energy storage unit is arranged in a cabin of the wind generating set and used for storing electric energy generated by the generator or releasing the stored electric energy.

In some possible embodiments, the first energy storage unit comprises at least one first energy storage component and at least one first power converter, and the first energy storage component is connected with the AC/DC converter through the first power converter; the first energy storage assembly stores the electric energy generated by the generator under the condition that the electric energy generated by the generator is larger than the load demand of a power grid or low-voltage ride through occurs; the first energy storage assembly releases stored electrical energy in the event that the electrical energy generated by the generator is less than the load demand of the electrical grid.

In some possible embodiments, the energy storage system further comprises a second energy storage unit; the second energy storage unit is connected with the DC/AC converter and is used for storing electric energy transmitted by the DC/AC converter or releasing the stored electric energy.

In some possible embodiments, the second energy storage unit comprises at least one second energy storage component and at least one second power converter, and the second energy storage component is connected with the DC/AC converter through the second power converter; the second energy storage component stores the electric energy transmitted by the DC/AC converter under the condition that the electric energy generated by the generator is larger than the load demand of the power grid; the second energy storage assembly releases the stored electric energy in case that the electric energy generated by the generator is smaller than the load demand of the power grid, or the sum of the electric energy generated by the generator and the electric energy released by the first energy storage unit is smaller than the load demand of the power grid.

In some possible embodiments, the first energy storage assembly comprises at least one of: the device comprises a storage battery assembly, a super capacitor assembly and a flywheel assembly; the flywheel assembly comprises a flywheel and a motor generator, and the flywheel is connected with the first power converter through the motor generator.

In some possible embodiments, the second energy storage assembly comprises at least one of: the device comprises a storage battery assembly, a super capacitor assembly and a flywheel assembly; the flywheel assembly comprises a flywheel and a motor generator, and the flywheel is connected with the second power converter through the motor generator.

In some possible embodiments, the energy storage system further comprises a master controller; the main controller is in communication connection with the first energy storage unit; the main controller is used for sending a first control instruction to the first energy storage unit under the condition that the electric energy generated by the generator is larger than the load demand of the power grid or low-voltage ride through occurs, and the first control instruction is used for controlling the first energy storage unit to store the electric energy generated by the generator; the main controller is further used for sending a second control instruction to the first energy storage unit under the condition that the electric energy generated by the generator is smaller than the load demand of the power grid, and the second control instruction is used for controlling the first energy storage unit to release the stored electric energy.

In some possible embodiments, the energy storage system further comprises a master controller; the main controller is in communication connection with the second energy storage unit; the main controller is used for sending a third control instruction to the second energy storage unit under the condition that the electric energy generated by the generator is larger than the load demand of the power grid, and the third control instruction is used for controlling the second energy storage unit to store the electric energy generated by the generator; the main controller is further used for sending a fourth control instruction to the second energy storage unit under the condition that the electric energy generated by the generator is smaller than the load demand of the power grid or the sum of the electric energy generated by the generator and the electric energy released by the first energy storage unit is smaller than the load demand of the power grid, and the fourth control instruction is used for controlling the second energy storage unit to release the stored electric energy.

In some possible embodiments, the energy storage system further comprises a pitch system; the variable pitch system is in communication connection with the main controller; the main controller is further used for sending a fifth control instruction to the variable pitch system under the condition that the electric energy generated by the generator is larger than the load demand of the power grid or low voltage ride through occurs, and the fifth control instruction is used for indicating the variable pitch system to adjust the pitch angle of the blades of the fan of the wind generating set so as to reduce the electric energy generated by the generator; the main controller is further used for sending a sixth control instruction to the variable pitch system under the condition that the electric energy generated by the generator is smaller than the load demand of the power grid, and the sixth control instruction is used for instructing the variable pitch system to adjust the pitch angle of the blades of the fan of the wind generating set so as to increase the electric energy generated by the generator.

In a second aspect, an embodiment of the present application provides a wind turbine generator system, including the energy storage system of the first aspect.

The embodiment of the application provides a wind generating set's energy storage system and wind generating set, and wind generating set's energy storage system is provided with the first energy storage unit who is connected with generator, AC/DC converter, and the first storage unit can set up in wind generating set's cabin as the storage unit of wind generating set machine side. The first energy storage unit can store the electric energy generated by the generator or release the electric energy stored by the first energy storage unit. Under the condition that the output of the wind generating set is limited due to a fault or other reasons, the first energy storage unit can store the electric energy output by the wind generating set, namely the electric energy generated by the generator, so that the bus voltage of the converter on the side of the wind generating set can be prevented from being increased, and the working reliability of the converter is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly described below, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an embodiment of an energy storage system of a wind turbine generator system provided in the present application;

FIG. 2 is a schematic diagram of an example of an energy storage system of the wind turbine generator set of FIG. 1;

FIG. 3 is a schematic diagram of another example of an energy storage system of the wind turbine generator set of FIG. 1;

FIG. 4 is a schematic structural diagram of another embodiment of an energy storage system of a wind turbine provided herein;

FIG. 5 is a schematic diagram of an example of an energy storage system of the wind turbine generator set of FIG. 4;

FIG. 6 is a schematic diagram of another example of an energy storage system of the wind turbine generator set of FIG. 4;

FIG. 7 is a schematic diagram of a communication connection between a master controller and other components in an energy storage system according to an embodiment of the present disclosure;

fig. 8 is a schematic structural diagram of an example of a wind turbine generator system provided in an embodiment of the present application.

Detailed Description

Features and exemplary embodiments of various aspects of the present application will be described in detail below, and in order to make objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are intended to be illustrative only and are not intended to be limiting. It will be apparent to one skilled in the art that the present application may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present application by illustrating examples thereof.

With the rapid development of science and technology, the demand of various fields on energy is gradually increased, and the application of new energy technology is wider. Wherein, the wind power generation technology using the wind generating set is also developed rapidly, and the application field is gradually expanded. The wind generating set is a device capable of converting wind energy into electric energy. The wind generating set can be connected with a power grid so as to interact with the power grid. However, when a fault such as grounding occurs on the grid side and low voltage ride through is performed, the output of the wind turbine generator system is limited, which may cause the bus voltage of the converter on the side of the wind turbine generator system to increase, and reduce the reliability of the converter operation.

The embodiment of the application provides a wind generating set's energy storage system and wind generating set, sets up the energy storage unit that can save the electric energy or release the electric energy of storage at wind generating set's machine side, avoids the busbar voltage of the converter of wind generating set machine side to rise to improve the reliability of converter work.

The energy storage system of the wind generating set and the wind generating set are described in turn below.

Fig. 1 is a schematic structural diagram of an embodiment of an energy storage system of a wind turbine generator system provided in the present application. As shown in fig. 1, the energy storage system 10 may include a generator 11, a first energy storage unit 12, a converter 13, and a step-up transformer 14. The converter 13 includes an AC/DC converter 131, which is an AC/DC converter 131, and a DC/AC converter 132, which is a DC/AC converter 132, which are connected. In some examples, the converter 13 may include, but is not limited to, a full power converter.

The generator 11 may be configured to be connected to a wind turbine 21 in a wind turbine generator set. The fan 21 may specifically be a direct drive fan. Specifically, the input of the generator 11 is configured as an output connection of the fan 21. The wind turbine 21 can convert wind energy into mechanical energy, and the generator 11 can convert the mechanical energy converted by the wind turbine 21 into electrical energy.

The generator 11 is connected to an AC/DC converter 131. Specifically, the output of the generator 11 may be connected to the three-phase input of the AC/DC converter 131. The electric power converted by the generator 11 may be transmitted to the AC/DC converter 131, and the AC/DC converter 131 may convert the electric power from an alternating current to a direct current. In some examples, the generator 11 may be specifically a permanent magnet synchronous generator, and may also be another type of generator, which is not limited herein.

The AC/DC converter 131 is connected to the DC/AC converter 132. The DC/AC converter 132 may convert the electrical energy from direct current to alternating current. In some examples, the current transformer 13 may further include a support capacitor C1, and the support capacitor C1 is connected in parallel with the AC/DC converter 131 and the DC/AC converter 132.

The DC/AC converter 132 is connected to the step-up transformer 14. Specifically, the three-phase output terminal of the DC/AC converter 132 is connected to the input terminal of the step-up transformer 14. The DC/AC converter 132 may transfer the electrical energy to the step-up transformer 14.

The first energy storage unit 12 is connected to the AC/DC converter 131 and may also be connected to the generator 11. Specifically, the first energy storage unit 12 is connected to a three-phase input terminal of the AC/DC converter 131 and an output terminal of the generator 11. The first energy storage unit 12 may be a three-phase energy storage unit, that is, one side of the first energy storage unit 12 connected to the AC/DC converter 131 may be a three-phase connection terminal. The three-phase connection terminals of the first energy storage unit 12 are correspondingly connected to the three-phase input terminals of the AC/DC converter 131. The first energy storage unit 12 is located at a machine side of the wind turbine generator system, and may be specifically disposed in a nacelle of the wind turbine generator system. The first energy storage unit 12 may be used to store electric energy generated by the generator 11 or to release stored electric energy.

The step-up transformer 14 may be configured to be connected to the grid 22 to transmit power to the grid 22 for power interaction between the wind turbine generator system and the grid 22.

In the embodiment of the present application, the energy storage system 10 of the wind turbine generator set is provided with the first energy storage unit 12 connected to the generator 11 and the AC/DC converter 131, and the first energy storage unit 12 may be provided in the nacelle of the wind turbine generator set as a storage unit on the side of the wind turbine generator set. The first energy storage unit 12 may store electric energy generated by the generator 11 or release electric energy stored in itself. Under the condition that the output of the wind generating set is limited due to a fault or other reasons, the first energy storage unit 12 can store the electric energy output by the wind generating set, namely the electric energy generated by the generator 11, so that the increase of the bus voltage of the converter 13 on the side of the wind generating set can be avoided, the problems of randomness and fluctuation of the electric energy on the side of the wind generating set are solved, the dynamic dispatching and control of electric energy interaction between the wind generating set and the power grid 22 are realized, the electric energy waste is avoided, the requirements of the power grid 22 can be met, the working reliability and safety of the converter 13 are improved, the safety and reliability of the wind generating set and an electric energy transmission system from the wind generating set to the power grid 22 are improved, and the electric energy interaction between the wind generating set and the power grid 22 is more stable and reliable.

In the case that the energy storage system 10 includes the first energy storage unit 12, when the grid 22 has a ground fault or a short-circuit fault and a low-voltage ride through occurs, the first energy storage unit 12 can store the electric energy output by the wind turbine generator system, i.e., the electric energy generated by the generator 11, so that the bus voltage of the converter 13 on the wind turbine generator system side can be prevented from rising. Correspondingly, the converter 13 does not need to be provided with a direct current braking system comprising a direct current chopper and an energy discharging resistor, so that the complexity of the converter 13 is reduced, the complexity of the energy storage system 10 is reduced, and the cost of the energy storage system 10 is also reduced.

The first energy storage unit 12 in the above embodiment will be described below. The first energy storage unit 12 may include at least one first energy storage component and at least one first power converter, and the kind and number of the first energy storage component and the first power converter in the first energy storage unit 12 are not limited herein. The first energy storage assembly may be connected to the AC/DC converter through a first power converter.

The first energy storage assembly stores the electrical energy generated by the generator 11 in the event that the electrical energy generated by the generator 11 is greater than the load demand of the grid 22 or a low voltage ride through occurs. Specifically, the electric energy generated by the generator 11 can be converted into electric energy meeting the energy storage standard of the first energy storage assembly through the first power converter, and the electric energy is stored in the first energy storage assembly. In case the generator 11 generates more electrical energy than the load demand of the grid 22, the bus voltage of the converter 13 will increase correspondingly. In the embodiment of the application, under the condition, the first energy storage assembly stores the electric energy generated by the generator 11, and avoids a large amount of electric energy from being accumulated at the converter 13, so that the bus voltage of the converter 13 is prevented from being increased, and the safety and reliability of the converter 13, the wind generating set and the power transmission system are ensured.

In the event that the electrical energy generated by the generator 11 is less than the load demand of the grid 22, the first energy storage component releases stored electrical energy. Specifically, the electric energy discharged from the first energy storage assembly may be converted into an alternating current in accordance with the optimal frequency and phase of the AC/DC converter 131 by the first power converter, and transmitted to the AC/DC converter 131. In the case where the power generated by the generator 11 is less than the load demand of the grid 22, the power generated by the generator 11 in real time cannot meet the demand of the grid 22. In this embodiment, the first energy storage assembly can output the electric energy stored by itself to the outside to compensate the electric energy transmitted to the power grid 22, so that the electric energy transmitted to the power grid 22 from the wind turbine generator system side can satisfy the load demand of the power grid 22.

The first energy storage unit 12 is arranged on the side of the wind generating set, and the first energy storage assembly and the first power converter are matched to realize the functions of improving the electric energy quality such as frequency modulation and voltage regulation on the electric energy source of the wind generating set, so that the working condition quality of the converter is improved.

In some examples, the first energy storage assembly in the above embodiments comprises at least one of: the device comprises a storage battery assembly, a super capacitor assembly and a flywheel assembly. The type of the first energy storage components in the first energy storage unit 12 and the number of each type of the first energy storage components in the first energy storage unit 12 are not limited herein.

Each battery assembly may include at least one battery, and the number of batteries in each battery assembly and the connection relationship of the batteries are not limited herein. Correspondingly, the first power converter connected to the battery assembly may be a power converter for a battery.

Each super capacitor assembly may include at least one super capacitor, and the number of super capacitors in each super capacitor assembly and the connection relationship of the super capacitors are not limited herein. Correspondingly, the first power converter connected with the super capacitor assembly can be a power converter for the super capacitor.

The flywheel assembly comprises a flywheel and a motor generator, and the flywheel is connected with the first power converter through the motor generator. The first power converter connected to the flywheel assembly may be an energy converter. The first power converter inputs electric energy into the motor generator to drive the motor generator to rotate, and the motor generator drives the flywheel to rotate. The flywheel can store kinetic energy of rotation, i.e. mechanical energy. It should be noted that the motor-generator in the flywheel assembly can be used as a motor in the case of energy storage of the flywheel and as a generator in the case of energy release of the flywheel, which can reduce the size and weight of the first energy storage unit 12 and thus the energy storage system 10.

For convenience of description, the first energy storage assembly including the battery assembly and the super capacitor assembly and the first energy storage assembly including the flywheel assembly are taken as examples for description.

Fig. 2 is a schematic diagram of an example of an energy storage system of the wind turbine generator set of fig. 1. Fig. 2 differs from fig. 1 in that the first energy storage unit 12 includes a battery assembly 121, a supercapacitor assembly 122, a power converter 123 for the battery, and a power converter 124 for the supercapacitor.

The battery pack 121 is connected to the battery power converter 123, and the battery power converter 123 is connected to the AC/DC converter 131 and the generator 11. The power converter 123 for the battery may be a three-phase AC/DC bidirectional converter, and the positive and negative ports of the power converter 123 for the battery are correspondingly connected to the positive and negative ports of the battery assembly 121.

The supercapacitor pack 122 is connected to a supercapacitor power converter 124, and the supercapacitor power converter 124 is connected to the AC/DC converter 131 and the generator 11. The power converter 124 for super capacitor can be a three-phase AC/DC bidirectional converter, and the positive and negative ports of the power converter 124 for super capacitor are correspondingly connected to the positive and negative ports of the super capacitor assembly 122. The three-phase connection terminal of the battery power converter 123 is connected in parallel with the three-phase connection terminal of the capacitor power converter 124.

In the case where the electric power generated by the generator 11 is larger than the load demand of the grid 22 or a low voltage ride through occurs, the power converter 123 for the storage battery and the power converter 124 for the super capacitor can convert the electric power generated by the generator 11 into electric power meeting the standards of the storage battery assembly 121 and the super capacitor assembly 122, respectively, and store the electric power in the storage battery assembly 121 and the super capacitor assembly 122.

In the case where the electric power generated by the generator 11 is smaller than the load demand of the grid 22, the electric power discharged from the storage battery assembly 121 and the super capacitor assembly 122 is converted into alternating current conforming to the optimum frequency and phase of the AC/DC converter 131 by the storage battery power converter 123 and the super capacitor power converter 124, respectively, and is transmitted to the AC/DC converter 131, and is transmitted to the grid 22 through the subsequent DC/AC converter 132 and the step-up transformer 14.

The energy density of the storage battery is large. The super capacitor has high power density, high charge and discharge efficiency and long cycle life. Use battery pack 121 and super capacitor subassembly 122 together, can combine that battery energy density is big, super capacitor power density is big, super capacitor charge-discharge efficiency is high, characteristics such as super capacitor cycle life is long, can improve the power output ability of first energy storage unit 12, reduce the internal loss of first energy storage unit 12, increase the discharge time of first energy storage unit 12, still can reduce battery pack 121's charge-discharge cycle number, the life of extension battery pack 121, and can reduce the volume of first energy storage unit 12, improve energy storage system 10's reliability, reduce energy storage system 10's maintenance cost.

Fig. 3 is a schematic diagram of another example of an energy storage system of the wind turbine generator set of fig. 1. Fig. 3 differs from fig. 1 in that the first energy storage unit 12 may comprise a flywheel assembly 125 and an energy converter 126. The flywheel assembly 125 includes a flywheel 1251 and a motor generator 1252.

The flywheel 1251 is connected to the motor generator 1252, the motor generator 1252 is connected to the energy converter 126, and the energy converter 126 is connected to the AC/DC converter 131 and the generator 11. The motor generator 1252 may be a dc integrated device having both a motor function and a generator function. The energy converter 126 may be a three-phase AC/DC bidirectional power electronic device, and three-phase connection terminals of the energy converter 126 are correspondingly connected with three-phase input terminals of the AC/DC converter 131.

In case the generator 11 generates electrical energy larger than the load demand of the grid 22 or a low voltage ride through occurs, the first energy storage unit 12 converts the electrical energy into mechanical energy. The energy converter 126 can convert the electric energy from ac to dc to drive the motor generator 1252, so as to drive the flywheel 1251 to rotate, and ensure the smooth, safe and reliable operation of the flywheel 1251. When the rotation speed of the flywheel 1251 needs to be increased, the motor generator 1252 can be controlled to increase speed by a variable frequency control method, such as constant torque control and constant power control, so as to drive the flywheel 1251 to accelerate. In the present example, the first energy storage unit 12 stores electrical energy in the form of kinetic energy. The flywheel 1251 may enter a low-voltage mode after reaching a certain rotational speed, and the energy converter 126 may provide low voltage to the motor generator 1252 to maintain the rotational speed at which the mechanical loss of energy stored by the flywheel 1251 is at a minimum level.

In case the generator 11 generates less electrical energy than the load demand of the grid 22, the first energy storage unit 12 converts the mechanical energy into electrical energy. The flywheel 1251 rotates to convert mechanical energy into electric energy by the motor generator 1252, and the energy converter 126 converts the electric energy converted by the motor generator into alternating current with a frequency and a phase corresponding to those of the AC/DC converter 131, and transmits the alternating current to the AC/DC converter 131 to be transmitted to the grid 22 through the subsequent DC/AC converter 132 and the step-up transformer 14. In this example, the output voltage and frequency of the motor generator 1252 continuously change with the change of the rotation speed of the flywheel 1251, and the rotation speed of the flywheel can be adjusted according to the specific operation condition of the power grid 22, so that the first energy storage unit 12 releases appropriate electric energy.

The flywheel assembly 125 has short charging time, high energy storage density, high power density and high energy conversion efficiency which can reach 85-95%, and can output larger energy in a short time. The flywheel assembly 125 is temperature insensitive, environmentally friendly, has a long service life and a high energy storage density without being affected by overcharging or overdischarging, and can further improve the performance of the energy storage system 10.

In some embodiments, the energy storage system may further include a second energy storage unit. Fig. 4 is a schematic structural diagram of another embodiment of an energy storage system of a wind turbine generator system provided in the present application. Fig. 4 differs from fig. 1 in that the energy storage system 10 shown in fig. 4 may further comprise a second energy storage unit 15.

The second energy storage unit 15 is connected to the DC/AC converter 132 and may also be connected to the step-up transformer 14. Specifically, the second energy storage unit 15 is connected to the three-phase output terminal of the DC/AC converter 132 and the input terminal of the step-up transformer 14. The second energy storage unit 15 may specifically be a three-phase energy storage unit, i.e. one side of the second energy storage unit 15 connected to the DC/AC converter 132 may be a three-phase connection terminal. The three-phase connection terminals of the second energy storage unit 15 are correspondingly connected to the three-phase output terminals of the DC/AC converter 132. The second energy storage unit 15 is located on the grid side of the wind generating set. The second energy storage unit 15 may be used to store the electric energy transmitted from the DC/AC converter 132 or release the stored electric energy.

When the intermittent energy in the power grid 22 has a power quality problem or a fault is detected, the second energy storage unit 15 may provide short-term standby power for a user of the power grid 22, so that the output of the wind turbine generator set matches with the predicted value, and the intermittent energy in the power grid 22 can be operated as schedulable energy. The second energy storage unit 15 can also participate in frequency modulation, so that balance between electric energy output and requirements is guaranteed. The second energy storage unit 15 can cooperate with the first energy storage unit 12 to store the surplus electric energy generated by the generator 11 under the condition that the electric energy generated by the generator is less than the load demand of the power grid 22, so as to further avoid the bus voltage of the converter 13 from rising, and ensure the safety and reliability of the converter 13, the wind generating set and the power transmission system. In the case where the generator 11 generates less electrical energy than the load demand of the grid 22, the self-stored electrical energy is released to meet the demand of the grid 22.

The second energy storing unit 15 in the above embodiment will be described below. The second energy storage unit 15 may include at least one second energy storage component and at least one second power converter, and the kind and number of the second energy storage component and the second power converter in the second energy storage unit 15 are not limited herein. The second energy storage assembly is connected with the DC/AC converter through a second power converter.

In the case where the power generated by the generator 11 is greater than the load demand of the grid 22, the second energy storage component stores the power transmitted from the DC/AC converter 132, and the power transmitted from the DC/AC converter 132 is the power generated by the generator 11. Specifically, the electric energy transmitted from the DC/AC converter 132 can be converted into electric energy conforming to the energy storage standard of the second energy storage assembly by the second power converter, and stored in the second energy storage assembly. The second energy storage assembly can store surplus electric energy when the electric energy generated by the generator 11 is larger than the load demand of the power grid 22, and energy waste is avoided.

In case the electrical energy generated by the generator 11 is smaller than the load demand of the grid 22, or the sum of the electrical energy generated by the generator and the electrical energy released by the first energy storage unit is smaller than the load demand of the grid 22, the second energy storage assembly releases the stored electrical energy. Specifically, the electrical energy discharged by the second energy storage assembly may be converted by the second power converter to alternating current consistent with the optimal frequency and phase of the DC/AC converter 132 and transmitted to the step-up transformer 14. In the case that the electric energy generated by the generator 11 is smaller than the load demand of the grid 22, or the sum of the electric energy generated by the generator and the electric energy released by the first energy storage unit is smaller than the load demand of the grid 22, the electric energy generated by the generator 11 in real time cannot meet the demand of the grid 22. In the embodiment of the present application, the second energy storage component can output the electric energy stored by itself to make up for the electric energy transmitted to the power grid 22, so that the electric energy transmitted to the power grid 22 can meet the load demand of the power grid 22.

In some examples, the second energy storage assembly in the above embodiments comprises at least one of: the device comprises a storage battery assembly, a super capacitor assembly and a flywheel assembly. The kind of the second energy storage components in the second energy storage unit 15 and the number of each kind of the second energy storage components in the second energy storage unit 15 are not limited herein.

Each battery assembly may include at least one battery, and the number of batteries in each battery assembly and the connection relationship of the batteries are not limited herein. Correspondingly, the second power converter connected to the battery assembly may be a power converter for a battery.

Each super capacitor assembly may include at least one super capacitor, and the number of super capacitors in each super capacitor assembly and the connection relationship of the super capacitors are not limited herein. Correspondingly, the second power converter connected with the super capacitor assembly can be a power converter for the super capacitor.

The flywheel assembly comprises a flywheel and a motor generator, and the flywheel is connected with the second power converter through the motor generator. The second power converter connected to the flywheel assembly may be an energy converter. The second power converter inputs electric energy into the motor generator to drive the motor generator to rotate, and the motor generator drives the flywheel to rotate. The flywheel can store kinetic energy of rotation, i.e. mechanical energy. It should be noted that the motor-generator in the flywheel assembly can be used as a motor in the case of energy storage of the flywheel and as a generator in the case of energy release of the flywheel, which can reduce the size and weight of the second energy storage unit 15, and thus the energy storage system 10.

For convenience of description, the second energy storage assembly including the battery assembly and the super capacitor assembly, and the second energy storage assembly including the flywheel assembly are taken as examples for description.

Fig. 5 is a schematic diagram of an example of an energy storage system of the wind turbine generator set of fig. 4. Fig. 5 differs from fig. 4 in that the second energy storage unit 15 includes a battery assembly 151, a supercapacitor assembly 152, a power converter 153 for a battery, and a power converter 154 for a supercapacitor.

The battery pack 151 is connected to a battery power converter 153, and the battery power converter 153 is connected to the DC/AC converter 132 and the step-up transformer 14. The power converter 153 for the battery may be a three-phase AC/DC bidirectional converter, and the positive and negative ports of the power converter 153 for the battery are correspondingly connected to the positive and negative ports of the battery assembly 151.

The super capacitor module 152 is connected to a super capacitor power converter 154, and the super capacitor power converter 154 is connected to the DC/AC converter 132 and the step-up transformer 14. The power converter 154 for super capacitor may be a three-phase AC/DC bidirectional converter, and the positive and negative ports of the power converter 154 for super capacitor are correspondingly connected to the positive and negative ports of the super capacitor assembly 152. The three-phase connection terminal of the battery power converter 153 is connected in parallel with the three-phase connection terminal of the capacitor power converter 154.

In the case where the electric power generated by the generator 11 is larger than the load demand of the grid 22, the power converter 153 for storage battery and the power converter 154 for super capacitor may convert the electric power transmitted from the DC/AC converter 132 into electric power conforming to the standards of the storage battery assembly 151 and the super capacitor assembly 152, respectively, and store the electric power in the storage battery assembly 151 and the super capacitor assembly 152.

In the case where the electric power generated by the generator 11 is smaller than the load demand of the grid 22, or the sum of the electric power generated by the generator and the electric power discharged from the first energy storage unit is smaller than the load demand of the grid 22, the electric power discharged from the battery pack 151 and the super capacitor pack 152 is converted into alternating current conforming to the optimum frequency and phase of the DC/AC converter 132 by the power converter for battery 153 and the power converter for super capacitor 154, respectively, and transmitted to the step-up transformer 14 to be transmitted to the grid 22.

The advantages and technical effects of the storage battery assembly 151 and the super capacitor assembly 152 in the second energy storage unit 15 can be seen from the related descriptions in the above embodiments, and are not described herein again.

Fig. 6 is a schematic diagram of another example of an energy storage system of the wind turbine generator set of fig. 4. Fig. 6 differs from fig. 4 in that the second energy storage unit 15 may comprise a flywheel assembly 155 and an energy converter 156. The flywheel assembly 155 includes a flywheel 1551 and a motor generator 1552.

The flywheel 1551 is connected to the motor generator 1552, the motor generator 1552 is connected to the energy converter 156, and the energy converter 156 is connected to the DC/AC converter 132 and the step-up transformer 14. The motor generator 1552 may be a dc integrated device having both motor and generator functions. Energy converter 156 may be a three-phase AC/DC bi-directional power electronic device, with the three-phase connections of energy converter 156 connected to the three-phase outputs of DC/AC converter 132.

In case the generator 11 generates electrical energy larger than the load demand of the grid 22, the second energy storage unit 15 converts the electrical energy into mechanical energy. The energy converter 156 can convert the electric energy from ac to dc to drive the motor generator 1552 to drive the flywheel 1551 to rotate, and ensure smooth, safe and reliable operation of the flywheel 1551. When the rotating speed of the flywheel 1551 needs to be increased, the motor generator 1552 can be controlled to increase in speed through a variable frequency control method, such as constant torque control and constant power control, so as to drive the flywheel 1551 to accelerate. In the present example, the second energy storage unit 15 stores electrical energy in the form of kinetic energy. The flywheel 1551 may enter a low voltage mode after reaching a certain rotational speed, and the energy converter 156 may provide low voltage to the motor generator 1552 to maintain the mechanical loss of energy stored by the flywheel 1551 at a minimum level of rotational speed.

In case the electrical energy generated by the generator 11 is smaller than the load demand of the grid 22, or the sum of the electrical energy generated by the generator and the electrical energy released by the first energy storage unit is smaller than the load demand of the grid 22, the second energy storage unit 15 converts the mechanical energy into electrical energy. The rotation of flywheel 1551 converts mechanical energy into electrical energy by motor generator 1552, and energy converter 156 converts the electrical energy converted by the motor generator into AC power having a frequency and phase consistent with that of DC/AC converter 132 for transmission to step-up transformer 14 for transmission to grid 22. In this example, the output voltage and frequency of the motor-generator 1552 continuously change with the change of the rotation speed of the flywheel 1551, and the rotation speed of the flywheel can be adjusted according to the specific operation condition of the power grid 22, so that the second energy storage unit 15 releases appropriate electric energy.

The advantages and technical effects of the flywheel assembly 155 in the second energy storage unit 15 can be found in the related description of the above embodiments, and are not described herein again.

In some embodiments, the energy storage system may further include a master controller, which may be a master controller of the wind turbine generator set. The main controller can be in communication connection with other components in the energy storage system to control the other components in the energy storage system to realize dynamic regulation of wind power energy of the wind generating set.

The master controller may be in communication with the first energy storage unit 12.

The main controller is configured to send a first control command to the first energy storage unit 12 when the electric power generated by the generator is greater than the load demand of the grid 22 or a low voltage ride through occurs. The first control instruction is used for controlling the first energy storage unit 12 to store the electric energy generated by the generator 11.

The main controller is further configured to send a second control command to the first energy storage unit 12 if the electric power generated by the generator is less than the load demand of the grid 22. The second control instruction is used for controlling the first energy storage unit 12 to release the stored electric energy.

In case the energy storage system 10 comprises a second energy storage unit 15, the master controller may also be in communication connection with the second energy storage unit 15.

The main controller is operable to send a third control command to the second energy storage unit 15 in case the electrical energy generated by the generator is larger than the load demand of the grid 22. The third control instruction is used to control the second energy storage unit 15 to store the electric energy generated by the generator 11.

The main controller may be further configured to send a fourth control command to the second energy storage unit 15 in case the power generated by the generator is less than the load demand of the grid 22 or the sum of the power generated by the generator and the power released by the first energy storage unit 12 is less than the load demand of the grid 22. The fourth control instruction is used for controlling the second energy storage unit 15 to release the stored electric energy.

In some examples, energy storage system 10 may also include a pitch system. The variable pitch system is in communication connection with the main controller.

The main controller is further configured to send a fifth control instruction to the pitch system if the electric power generated by the generator 11 is greater than the load demand of the grid 22 or a low voltage ride through occurs. The fifth control instruction is used for instructing the pitch system to adjust the pitch angle of the blades of the wind turbine 21 of the wind turbine generator set so as to reduce the electric energy generated by the generator 11.

The main controller is further configured to send a sixth control command to the pitch system if the electrical energy generated by the generator 11 is less than the load demand of the grid 22. The sixth control instruction is used for instructing the pitch system to adjust the pitch angle of the blades of the wind turbine 21 of the wind turbine generator set so as to increase the electric energy generated by the generator 11.

Communication between the main controller and the first energy storage unit 12, the second energy storage unit 15, and the pitch system will be described below by taking an example in which the first energy storage unit 12 includes a first energy storage component and a first power converter, and the second energy storage unit 15 includes a second energy storage component and a second power converter. Fig. 7 is a schematic diagram of communication connections between a main controller and other components in an energy storage system according to an embodiment of the present application. As shown in fig. 7, the main controller 31 may be communicatively connected to the first power converter 32 in the first energy storage unit 12, the second power converter 33 in the second energy storage unit 15, the pitch system 34, and the converter 13. Specifically, the communication connection may be a wired communication connection or a wireless communication connection, and is not limited herein.

In the case that the electric energy generated by the generator 11 is larger than the load demand of the power grid 22 or a low voltage ride through occurs, the main controller 31 may specifically send a first control command to the first power converter 32 in the first energy storage unit 12, and control the first power converter 32 to be put into use, so as to store the electric energy generated by the generator 11 in the first energy storage assembly 35, or convert the electric energy generated by the generator 11 into other forms of energy to be stored in the first energy storage assembly 35.

In the case that the electric energy generated by the generator 11 is larger than the load demand of the power grid 22, the main controller 31 may specifically send a third control command to the second power converter 33 in the second energy storage unit 15, so as to control the second power converter 33 to be put into use, so as to store the electric energy generated by the generator 11 and transmitted to the DC/AC converter 132 in the second energy storage assembly 36, or convert the electric energy generated by the generator 11 and transmitted to the DC/AC converter 132 into other forms of energy to be stored in the second energy storage assembly 36.

When the electric energy generated by the generator 11 is greater than the load demand of the grid 22 or a low voltage ride through occurs, the main controller 31 sends a fifth control instruction to the pitch system 34, so that the pitch system 34 performs pitch angle adjustment of the blades, and the electric energy generated by the generator 11 is reduced.

In the case that the electric energy generated by the generator 11 is smaller than the load demand of the grid 22, the main controller 31 may specifically send a second control command to the first power converter 32 in the first energy storage unit 12, and control the first power converter 32 to be put into use, so as to release the electric energy stored in the first energy storage assembly 35 to the AC/DC converter 131, and transmit the electric energy to the grid 22 through the subsequent DC/AC converter 132 and the step-up transformer 14.

In the case that the electric energy generated by the generator 11 is less than the load demand of the grid 22 or the sum of the electric energy generated by the generator and the electric energy released by the first energy storage unit 12 is less than the load demand of the grid 22, the main controller 31 may specifically send a fourth control command to the second power converter 33 in the second energy storage unit 15, and control the second power converter 33 to be put into use, so as to release the electric energy stored in the second energy storage assembly 36 to the step-up transformer 14 for transmission to the grid 22.

When the electric energy generated by the generator 11 is smaller than the load demand of the power grid 22 or low voltage ride through occurs, the main controller 31 sends a sixth control instruction to the pitch system 34, so that the pitch system 34 performs pitch angle adjustment of the blades, and the electric energy generated by the generator 11 is increased.

Through the control of the main controller 31 on the first energy storage unit 12, the second energy storage unit 15 and the pitch control system 34, the dynamic scheduling and control of electric energy interaction between the wind generating set and the power grid 22 can be realized, the electric energy waste is avoided, the requirement of the power grid 22 can be met, and the electric energy interaction between the wind generating set and the power grid 22 is more stable and reliable.

The present application also provides a wind power plant comprising the energy storage system 10 in the above embodiment. Fig. 8 is a schematic structural diagram of an example of a wind turbine generator system provided in an embodiment of the present application. As shown in fig. 8, the wind turbine generator system includes a nacelle 41 and a tower bottom 42. The wind turbine 21, the generator 11, the first energy storage unit 12, the main controller 31 and the pitch system 34 in the above embodiments may be disposed in the nacelle 41, and the converter 13, the second energy storage unit 15 and the step-up transformer 14 may be disposed at the tower bottom, which is not limited herein.

The wind turbine generator set includes the energy storage system 10, and specific contents may refer to relevant descriptions in the above embodiments, and are not described herein again.

It should be clear that the embodiments in this specification are described in a progressive manner, and the same or similar parts in the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. For the wind park embodiment, reference may be made to the description of the energy storage system embodiment of the wind park. The present application is not limited to the specific configurations described above and shown in the drawings. Those skilled in the art may make various changes, modifications and additions after comprehending the spirit of the present application. Also, a detailed description of known techniques is omitted herein for the sake of brevity.

It will be appreciated by persons skilled in the art that the above embodiments are illustrative and not restrictive. Different features which are present in different embodiments may be combined to advantage. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art upon studying the drawings, the specification, and the claims. In the claims, the term "comprising" does not exclude other means or steps; the word "a" or "an" does not exclude a plurality; the terms "first" and "second" are used to denote a name and not to denote any particular order. Any reference signs in the claims shall not be construed as limiting the scope. The functions of the various parts appearing in the claims may be implemented by a single hardware or software module. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

1. The energy storage system of the wind generating set is characterized by comprising a generator, a first energy storage unit, a converter and a step-up transformer; the converter comprises an alternating current/direct current AC/DC converter and a direct current/alternating current DC/AC converter which are connected;

the generator is connected with the AC/DC converter, the DC/AC converter is connected with the step-up transformer, the first energy storage unit is connected with the AC/DC converter, and the first energy storage unit is also connected with the generator;

the first energy storage unit is arranged in a cabin of the wind generating set and used for storing electric energy generated by the generator or releasing the stored electric energy.

2. The energy storage system of claim 1, wherein the first energy storage unit comprises at least one first energy storage component and at least one first power converter, the first energy storage component being connected to the AC/DC converter through the first power converter;

the first energy storage component stores the electric energy generated by the generator under the condition that the electric energy generated by the generator is larger than the load demand of a power grid or low-voltage ride through occurs;

the first energy storage assembly releases stored electrical energy when electrical energy generated by the generator is less than a load demand of the electrical grid.

3. The energy storage system of claim 1, further comprising a second energy storage unit;

the second energy storage unit is connected with the DC/AC converter and is used for storing electric energy transmitted by the DC/AC converter or releasing the stored electric energy.

4. The energy storage system of claim 3, wherein the second energy storage unit comprises at least one second energy storage component and at least one second power converter, the second energy storage component being connected to the DC/AC converter through the second power converter;

the second energy storage component stores the electric energy transmitted by the DC/AC converter under the condition that the electric energy generated by the generator is larger than the load demand of the power grid;

and under the condition that the electric energy generated by the generator is less than the load demand of the power grid, or the sum of the electric energy generated by the generator and the electric energy released by the first energy storage unit is less than the load demand of the power grid, the second energy storage component releases the stored electric energy.

5. The energy storage system of claim 2, wherein the first energy storage component comprises at least one of:

the device comprises a storage battery assembly, a super capacitor assembly and a flywheel assembly;

the flywheel assembly comprises a flywheel and a motor generator, and the flywheel is connected with the first power converter through the motor generator.

6. The energy storage system of claim 4, wherein the second energy storage component comprises at least one of:

the flywheel assembly comprises a flywheel and a motor generator, and the flywheel is connected with the second power converter through the motor generator.

7. The energy storage system of claim 1, further comprising a master controller;

the main controller is in communication connection with the first energy storage unit;

the main controller is used for sending a first control instruction to the first energy storage unit under the condition that the electric energy generated by the generator is larger than the load demand of a power grid or low-voltage ride through occurs, wherein the first control instruction is used for controlling the first energy storage unit to store the electric energy generated by the generator;

the main controller is further configured to send a second control instruction to the first energy storage unit when the electric energy generated by the generator is smaller than the load demand of the power grid, where the second control instruction is used to control the first energy storage unit to release the stored electric energy.

8. The energy storage system of claim 3, further comprising a master controller;

the main controller is in communication connection with the second energy storage unit;

the main controller is used for sending a third control instruction to the second energy storage unit under the condition that the electric energy generated by the generator is larger than the load demand of the power grid, and the third control instruction is used for controlling the second energy storage unit to store the electric energy generated by the generator;

the main controller is further configured to send a fourth control instruction to the second energy storage unit when the electric energy generated by the generator is less than the load demand of the power grid or the sum of the electric energy generated by the generator and the electric energy released by the first energy storage unit is less than the load demand of the power grid, where the fourth control instruction is used to control the second energy storage unit to release the stored electric energy.

9. The energy storage system of claim 7 or 8, further comprising a pitch system;

the variable pitch system is in communication connection with the main controller;

the main controller is further configured to send a fifth control instruction to the pitch system when the electric energy generated by the generator is greater than a load demand of the power grid or a low voltage ride through occurs, where the fifth control instruction is used to instruct the pitch system to adjust a pitch angle of a blade of a fan of the wind turbine generator system, so as to reduce the electric energy generated by the generator;

the main controller is further configured to send a sixth control instruction to the pitch system when the electric energy generated by the generator is smaller than the load demand of the power grid, where the sixth control instruction is used to instruct the pitch system to adjust a pitch angle of a blade of a fan of the wind turbine generator system, so as to increase the electric energy generated by the generator.

10. A wind park comprising an energy storage system according to any one of claims 1 to 9.