Energy storage device in variable pitch system and variable pitch system

Abstract

The utility model provides an energy storage device in a variable pitch system and the variable pitch system. Wherein the energy storage device comprises a super capacitor module and a battery pack; the super-capacitor module and the battery pack are respectively connected with the rectifying circuit; the rectifying circuit is connected with a power grid; the rectifying circuit is further connected with the inverter circuit, and the inverter circuit is connected with a variable-pitch motor in the variable-pitch system. When a power grid supplies power, electric energy is rectified by the rectifying circuit and then charges the super capacitor module and the battery pack; when the power grid stops supplying power, the super-capacitor module or the battery pack feeds back electric energy to the power grid. The energy storage device is additionally provided with the battery pack, and the battery pack is matched with the super capacitor module, so that the electric energy storage amount of the energy storage device is greatly increased; when the power grid is powered off, power can be supplied to the pitch control system for pitch retracting, yaw work and the like, and the electric energy requirements in various scenes can be met.

Description

Technical Field

[0001] The utility model relates to the technical field of wind power, in particular to an energy storage device in a variable pitch system and a variable pitch system. Background Art

[0002] The pitch drive, pitch motor and backup power supply are the core components of the pitch system. The backup power supply is usually composed of supercapacitor modules in series. When the input power is off or an abnormality occurs, the yaw system cannot work, and the energy stored in the supercapacitor module can meet the pitch system to complete the pitch retraction operation; however, the energy density of the supercapacitor module is low, and the amount of electricity stored is small, which makes it difficult to meet the power demand in specific scenarios. Utility Model Content

[0003] In view of this, an object of the present invention is to provide an energy storage device and a pitch system in a pitch system to increase the amount of electrical energy storage and meet the electrical energy requirements in various scenarios.

[0004] In the first aspect, an embodiment of the utility model provides an energy storage device in a variable pitch system, the energy storage device includes a supercapacitor module and a battery pack; the supercapacitor module and the battery pack are respectively connected to a rectifier circuit, and the rectifier circuit is connected to a power grid; the rectifier circuit is also connected to an inverter circuit, and the inverter circuit is connected to a variable pitch motor in the variable pitch system; when the power grid supplies power, the electric energy is rectified by the rectifier circuit to charge the supercapacitor module and the battery pack; when the power grid stops supplying power, the supercapacitor module or the battery pack feeds back electric energy to the power grid.

[0005] The energy storage device also includes a first DC / DC voltage conversion circuit; the first DC / DC voltage conversion circuit is arranged between the rectifier circuit and the battery pack; the first DC / DC voltage conversion circuit is used to charge the battery pack after converting the input electrical energy into a first specified voltage.

[0006] The above-mentioned rectifier circuit includes multiple ones; the battery pack is connected to one of the multiple rectifier circuits through a first DC / DC voltage conversion circuit.

[0007] The first DC / DC voltage conversion circuit comprises a BUCK circuit, one end of the BUCK circuit is connected to the bus bar, and the other end of the BUCK circuit is connected to the battery pack.

[0008] The energy storage device also includes a boost circuit, which is disposed between the battery pack and the rectifier circuit. The boost circuit is used to boost the electric energy provided by the battery pack and input it into the rectifier circuit, and then input the inverted electric energy into the power grid after inverting it through the rectifier circuit.

[0009] The boost circuit comprises a Boost circuit; one end of the Boost circuit is connected to a battery pack, and the other end of the Boost circuit is connected to a rectifier circuit.

[0010] The energy storage device also includes a second DC / DC voltage conversion circuit; the second DC / DC voltage conversion circuit is arranged between the rectifier circuit and the supercapacitor module; the second DC / DC voltage conversion circuit is used to charge the supercapacitor module after converting the input electrical energy into a second specified voltage.

[0011] The second DC / DC voltage conversion circuit comprises a BUCK circuit; one end of the BUCK circuit is connected to the bus, and the other end is connected to the supercapacitor module.

[0012] The energy storage device further comprises a discharge branch of a supercapacitor module; a diode device is arranged on the discharge branch; one end of the discharge branch is connected to the supercapacitor module, and the other end is connected to a rectifier circuit.

[0013] The above-mentioned supercapacitor module and battery pack are connected to the same DC / DC circuit; the DC / DC circuit is provided with an on-off control device; the on-off control device includes a first connection point and a second connection point; the first connection point is connected to the battery pack and the supercapacitor module at the same time; the second connection point is connected to the supercapacitor module; when the on-off control device is connected to the first connection point, the battery pack and the supercapacitor module are charged at the same time; when the on-off control device is connected to the second connection point, the supercapacitor module is charged.

[0014] In the second aspect, an embodiment of the utility model provides a pitch system, which includes a rectifier circuit, an inverter circuit, a pitch motor and an energy storage device in the above-mentioned pitch system; the energy storage device is connected to the rectifier circuit; the rectifier circuit, the inverter circuit and the pitch motor are connected in sequence.

[0015] The embodiments of the present invention bring the following beneficial effects:

[0016] The energy storage device and the pitch system in the above-mentioned pitch system include a supercapacitor module and a battery pack; the supercapacitor module and the battery pack are respectively connected to the rectifier circuit, and the rectifier circuit is connected to the power grid; the rectifier circuit is also connected to the inverter circuit, and the inverter circuit is connected to the pitch motor in the pitch system; when the power grid is powered, the electric energy is rectified by the rectifier circuit and then charges the supercapacitor module and the battery pack; when the power grid stops supplying electricity, the supercapacitor module or the battery pack feeds back electric energy to the power grid. The energy storage device is provided with a supercapacitor module and a battery pack. When the power grid is powered, the supercapacitor module and the battery pack are powered. Since the battery pack is additionally provided, the battery pack and the supercapacitor module cooperate with each other, thereby greatly increasing the electric energy storage capacity of the energy storage device; when the power grid is cut off, the pitch system can be powered for retracting the pitch and yaw operation, etc., which can meet the electric energy requirements in various scenarios.

[0017] Other features and advantages of the utility model will be described in the following description, and partly become apparent from the description, or understood by practicing the utility model. The purpose and other advantages of the utility model are realized and obtained by the structures specifically pointed out in the description, claims and drawings.

[0018] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are some implementation methods of the utility model. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A schematic diagram of the structure of an energy storage device in a pitch control system provided by an embodiment of the utility model;

[0021] Figure 2 A schematic diagram of the flow of electric energy during the charging and discharging process of an energy storage device in a pitch control system provided by an embodiment of the utility model;

[0022] Figure 3 A partial structural schematic diagram of a first variable pitch system including an energy storage device provided in an embodiment of the utility model;

[0023] Figure 4 A partial structural schematic diagram of a second variable pitch system including an energy storage device provided in an embodiment of the utility model;

[0024] Figure 5 A topological circuit diagram of a group of rectifier circuits, inverter circuits, variable pitch motors, and energy storage devices provided in an embodiment of the utility model;

[0025] Figure 6 A schematic diagram of another circuit topology of an energy storage device provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the utility model clearer, the technical solution of the utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0027] The variable pitch drive is a key control component of wind power transmission equipment. Its main function is to use the frequency converter to control the operation of the motor, which then drives the gears and blades to rotate, thereby controlling the vertical wind direction of the blades, so that the blades are always in a relatively safe working state; the wind turbine can operate and generate electricity efficiently, and will not be dismembered due to excessive wind volume and excessive blade speed, thus protecting the entire wind turbine from long-term safe and efficient operation.

[0028] The pitch system is mainly composed of a pitch cabinet and a pitch motor. Taking a wind turbine generator set including three blade shafts as an example, a pitch system includes three pitch cabinets. The pitch cabinet is composed of a pitch drive, a backup power supply, and electrical components, among which the electrical components include reactors, heaters, sensors, fuses, switches, external switching power supplies, etc. Each pitch cabinet drives a set of motors. The pitch drive, pitch motor, and backup power supply are the three core components of the pitch system. The main functions are realized by the pitch drive. The pitch drive is a single component with highly concentrated functions. All motor drive functions are realized by the pitch drive, and the pitch drive can work independently.

[0029] The backup power supply is usually composed of supercapacitor modules connected in series, and the supercapacitor module is composed of supercapacitor monomers. When the input power is off or abnormal, the energy stored in the supercapacitor module is required to meet the pitch system to complete the pitch retraction. The pitch system retraction characteristics are that it requires a large instantaneous current and a short time. The advantages of using supercapacitors are high power density, very large instantaneous current output, and long service life. The disadvantages are low energy density and less electrical energy stored in supercapacitors.

[0030] Based on the above problems, this embodiment provides an energy storage device in a variable pitch system and a variable pitch system, which can be applied in the field of wind power.

[0031] See also Figure 1 A schematic structural diagram of an energy storage device in a pitch control system is shown, wherein the energy storage device includes a super capacitor module 10 and a battery pack 12;

[0032] exist Figure 1 In the example, three supercapacitor modules are shown. For a wind turbine generator set including three blade shafts, each blade shaft corresponds to a supercapacitor module; the supercapacitor module and the battery pack are respectively connected to the rectifier circuit, and the rectifier circuit is connected to the power grid; the rectifier circuit is also connected to the inverter circuit, and the inverter circuit is connected to the pitch motor in the pitch system; each supercapacitor module is connected to a rectifier circuit.

[0033] In the pitch system, electric energy is input from the grid, rectified by the rectifier circuit, and then driven by the inverter circuit to operate the pitch motor. Each blade shaft is equipped with a pitch motor, which is equipped with a set of rectifier circuits and inverter circuits; then, each rectifier circuit is connected to a supercapacitor module; a rectifier circuit in the pitch system is connected to the above-mentioned battery pack.

[0034] The supercapacitor module may include one or more supercapacitors, and the supercapacitor may specifically be a double-layer capacitor. The battery pack may be a lithium battery or a lead-acid battery.

[0035] When the grid supplies power, the electric energy is rectified by the rectifier circuit and then charged to the supercapacitor module and battery pack; when the grid stops supplying power, the supercapacitor module or battery pack feeds back electric energy to the grid. It should be noted that the rectifier circuit has an inverter function, and the electric energy in the supercapacitor module or battery pack is inverted by the rectifier circuit and then input into the grid to power other components.

[0036] The electric energy stored in the supercapacitor module can be used to supply the blades for retraction alone, and the electric energy stored in the battery pack can be used to supply power to other devices on the grid side, such as the yaw drive.

[0037] The energy storage device in the above-mentioned variable pitch system includes a supercapacitor module and a battery pack; the supercapacitor module and the battery pack are respectively connected to the rectifier circuit, and the rectifier circuit is connected to the power grid; the rectifier circuit is also connected to the inverter circuit, and the inverter circuit is connected to the variable pitch motor in the variable pitch system; when the power grid is powered, the electric energy is rectified by the rectifier circuit and then charges the supercapacitor module and the battery pack; when the power grid stops supplying electricity, the supercapacitor module or the battery pack feeds back electric energy to the power grid. The energy storage device is provided with a supercapacitor module and a battery pack. When the power grid is powered, the supercapacitor module and the battery pack are powered. Since the battery pack is additionally provided, the battery pack and the supercapacitor module cooperate with each other, thereby greatly increasing the electric energy storage capacity of the energy storage device; when the power grid is powered off, the variable pitch system can be powered for retracting the pitch and yaw operations, etc., which can meet the electric energy requirements in various scenarios.

[0038] Figure 2 The flow of electric energy in the energy storage device during the charging and discharging process is shown.

[0039] During the charging process, electric energy flows from the power grid to each rectifier circuit, and then from each rectifier circuit to the correspondingly connected supercapacitor module, thereby charging the supercapacitor module; in addition, the battery pack is connected to any one of the multiple rectifier circuits, and electric energy flows from the rectifier circuit to the battery pack to charge the battery pack.

[0040] During the discharge process, the electric energy output by the supercapacitor module flows to the corresponding rectifier circuit, and then flows to the grid from the rectifier circuit; the charging branch and the discharging branch of the supercapacitor module are the same, so the rectifier circuit and the supercapacitor module are connected by a bidirectional arrow. The charging branch and the discharging branch between the grid and the rectifier circuit are the same and are also connected by a bidirectional arrow.

[0041] For the battery pack, during the charging process, the charging electric energy flows from one of the rectifier circuits to the battery pack, which is a one-way arrow; when the battery pack is discharging, the discharge electric energy flows to each rectifier circuit at the same time, and the charging branch and the discharging branch are different. Therefore, the battery pack is connected to the discharge branch of each rectifier circuit with a one-way arrow.

[0042] See also Figure 3 A partial structural schematic diagram of a first variable pitch system including an energy storage device is shown.

[0043] Among them, the three-wire input is the power input interface on the grid side; the power input interface is also connected to the yaw system. The power input interface is connected to three IGBT (Insulate-Gate Bipolar Transistor) rectifier circuits; the rectifier circuit is composed of IGBTs. The inverter circuit is connected to the pitch motor. Figure 3 The figure shows three groups of branches in which a rectifier circuit, an inverter circuit and a pitch motor are connected in series.

[0044] The energy storage device further includes a first DC / DC voltage conversion circuit; the first DC / DC voltage conversion circuit is arranged between the rectifier circuit and the battery pack; the first DC / DC voltage conversion circuit is used to charge the battery pack after converting the input electric energy into a first specified voltage. The first specified voltage is usually the charging voltage of the battery pack.

[0045] The above-mentioned rectifier circuit includes a plurality of rectifier circuits; the battery pack is connected to one of the rectifier circuits through a first DC / DC voltage conversion circuit. The first DC / DC voltage conversion circuit is Figure 3 In the invention, the battery pack is connected to one of the IGBT rectifier circuits, and a DC / DC circuit is arranged on the connecting branch.

[0046] The pitch cabinet of the pitch system includes three groups of IGBT rectifier circuits, three groups of inverter circuits and three groups of supercapacitor modules. Each group of supercapacitor modules uses a DC / DC circuit for charging. Any group of IGBT rectifier circuits is selected, and a DC / DC circuit is connected to charge the battery pack after rectification and filtering. The battery pack is then connected to the bus through three-way boost circuits for discharge. The charging voltage of the battery pack is lower than the charging voltage of the supercapacitor module.

[0047] When the three-phase input loses power, the supercapacitor module discharges first to complete the retraction of the blades. After the retraction is completed, the battery pack begins to discharge by boosting the voltage, and then inverts the voltage through the IGBT rectifier circuit to supply the grid-side equipment, such as the yaw drive, for operation.

[0048] Figure 4 A partial structural schematic diagram of a second pitch system including an energy storage device is shown; Figure 3 The structure is different in that Figure 4 The battery pack is connected to only one boost circuit, which has three output terminals, each of which is connected to an IGBT rectifier circuit, and a diode is provided on the branch between each output terminal and the IGBT rectifier circuit to prevent current from flowing in the reverse direction.

[0049] See also Figure 5 A topological circuit diagram of a set of rectifier circuits, inverter circuits, variable pitch motors, and energy storage devices is shown. The rectifier circuit includes three branches, each of which has two IGBT switches connected in series. The inverter circuit has the same structure as the rectifier circuit.

[0050] The first DC / DC voltage conversion circuit includes a BUCK circuit, one end of which is connected to the busbar, and the other end is connected to the battery pack. The BUCK circuit includes components such as a switch tube, a diode, an inductor, and a capacitor. The BUCK circuit can be used to reduce the voltage and charge the battery pack with the electric energy after the voltage reduction.

[0051] The energy storage device also includes a boost circuit, which is disposed between the battery pack and the rectifier circuit. The boost circuit is used to boost the electric energy provided by the battery pack and input it into the rectifier circuit, and then input the inverted electric energy into the power grid after inverting it through the rectifier circuit.

[0052] In actual implementation, the battery pack is connected to each rectifier circuit via a boost circuit, and a diode is also provided on the branch where the boost circuit is located to prevent current reverse flow. The branch where the boost circuit is located can be understood as a discharge circuit of the battery pack.

[0053] Continue to refer Figure 5 The boost circuit includes a boost circuit; one end of the boost circuit is connected to a battery pack, and the other end is connected to a rectifier circuit. The bosst circuit includes components such as a switch tube and an inductor. The boost circuit may also be an isolated DC / DC circuit.

[0054] The energy storage device further includes a second DC / DC voltage conversion circuit; the second DC / DC voltage conversion circuit is arranged between the rectifier circuit and the supercapacitor module; the second DC / DC voltage conversion circuit is used to charge the supercapacitor module after converting the input electric energy into a second specified voltage. The second specified voltage is usually the charging voltage of the supercapacitor module. The charging voltage of the battery pack is less than the charging voltage of the supercapacitor module.

[0055] The second DC / DC voltage conversion circuit includes a BUCK circuit; one end of the BUCK circuit is connected to the bus, and the other end is connected to the supercapacitor module. Figure 5 In the embodiment, a BUCK circuit is arranged on the left side of the supercapacitor module, one end of the BUCK circuit is connected to the supercapacitor module, and the other end is connected to the positive cable and the negative cable of the DC bus. The second DC / DC voltage conversion circuit may also be an isolated DC / DC circuit.

[0056] The energy storage device also includes a discharge branch of a supercapacitor module; a diode device is arranged on the discharge branch; one end of the discharge branch is connected to the supercapacitor module, and the other end is connected to the rectifier circuit. In the variable pitch system, each rectifier circuit is connected to a supercapacitor module, and the discharge branch of the supercapacitor module is also connected to the rectifier circuit.

[0057] In the above Figure 5 In the example, the Buck circuit is used to charge the supercapacitor module, and the supercapacitor module is discharged through the diode. The Buck circuit is selected to charge the battery pack, and the battery pack is discharged through the Boost circuit. The charging voltage of the battery pack is lower than the charging voltage of the supercapacitor module.

[0058] When the three-phase power supply is cut off, since the charging voltage of the supercapacitor module is much greater than the charging voltage of the battery pack, the supercapacitor module discharges first to meet the pitch retraction action of the variable pitch system. After the voltage of the supercapacitor module drops to a certain level, Boost starts working and the battery pack starts discharging to meet the work of other equipment on the grid side.

[0059] Figure 6 Another circuit topology schematic diagram of the energy storage device is shown.

[0060] The above-mentioned supercapacitor module and battery pack are connected to the same DC / DC circuit; the DC / DC circuit is provided with an on-off control device; the on-off control device includes a first connection point and a second connection point; the first connection point is connected to the battery pack and the supercapacitor module at the same time; the second connection point is connected to the supercapacitor module; when the on-off control device is connected to the first connection point, the battery pack and the supercapacitor module are charged at the same time; when the on-off control device is connected to the second connection point, the supercapacitor module is charged.

[0061] The on-off control device can be implemented by a single-pole double-throw switch; the on-off control device includes a switch head, one end of which is fixedly connected to the DC / DC circuit; the other end of which is connected to the first connection point or the second connection point. Figure 6 The on-off control device includes three connection points, the left connection point is fixedly connected to the switch head and the DC / DC circuit, and the right side has two connection points, the lower connection point is the above-mentioned first connection point, and the upper connection point is the above-mentioned second connection point; the first connection point is simultaneously connected to the positive terminal of the battery pack and the positive terminal of the supercapacitor module; when the switch head is connected to the first connection point, the battery pack and the supercapacitor module are charged at the same time through the DC / DC circuit; the second connection point is only connected to the positive terminal of the supercapacitor module, and when the switch head is connected to the second connection point, only the supercapacitor module is charged through the DC / DC circuit.

[0062] It should be noted that the on-off control device first connects to the first connection point, and uses a set of Buck circuits to charge the battery pack and the supercapacitor module at the same time. When the battery pack is fully charged, the on-off control device disconnects the first connection point and connects the second connection point to continue charging the supercapacitor module. After the battery pack naturally loses power to a certain extent, the on-off control device disconnects the second connection point and connects the first connection point to supplement the battery pack and charge the supercapacitor module at the same time. In the above process, the supercapacitor module is always in a charged state.

[0063] This embodiment also provides a pitch system, which includes a rectifier circuit, an inverter circuit, a pitch motor and an energy storage device in the above pitch system; the energy storage device is connected to the rectifier circuit; the rectifier circuit, the inverter circuit and the pitch motor are connected in sequence.

[0064] The pitch system in this embodiment no longer retains the pitch drive, and the three pitch cabinets are merged into one pitch cabinet. One pitch system corresponds to one pitch cabinet, which drives three sets of pitch motors. The functions of the original pitch drive are split and designed in a modular form. All modules are directly arranged and installed in the pitch cabinet, and re-composed into a new pitch cabinet with supercapacitor modules and electrical parts. All power devices directly rely on the pitch cabinet for heat dissipation. One pitch cabinet integrates three pitch drive functions and three sets of supercapacitor modules.

[0065] The backup power supply in the pitch system is no longer limited to supercapacitor modules. A battery pack will be used as another backup power supply outside the pitch cabinet. The backup power supply consists of three supercapacitor modules and a battery pack. The purpose is to meet the instantaneous large current required by the pitch system when retracting the slurry, and to store enough energy for yaw operation. In the rectifier circuit, the thyristor-type rectifier circuit is cancelled and replaced with an IGBT full-bridge rectifier circuit; when the IGBT rectifier circuit is controlled to be turned on, the DC power of the bus can be reversely transmitted to the power grid to achieve grid connection. The advantage of the grid-connected design is that when the input power is off or abnormal, the energy stored in the backup power supply can not only meet the pitch system's slurry retraction action, but also reversely invert and transmit to the power grid for the yaw system to work. The yaw system performs the next action to achieve the coordinated work of the pitch system and the yaw system. At the same time, the grid-connected design can directly transmit the electric energy of motor braking or reversing to the power grid, eliminating the braking resistor and reducing the cost and volume of raw materials.

[0066] The energy storage device and the pitch system in the pitch system provided in this embodiment have a hybrid backup power supply design, which can not only meet the instantaneous large current required when the pitch system is retracting the pitch, but also meet the sufficient energy required for storing yaw operations; the grid-connected design is adopted, and the DC power of the backup power supply can be inverted for use by the yaw drive, thereby achieving coordinated operation of the pitch system and the yaw system; the modular centralized design saves volume and cost.

[0067] In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0068] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the utility model can be embodied in the form of a software product in essence or in other words, the part that contributes to the prior art or the part of the technical solution. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the utility model. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0069] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0070] Finally, it should be noted that the above embodiments are only specific implementation methods of the utility model, which are used to illustrate the technical solution of the utility model, rather than to limit it. The protection scope of the utility model is not limited thereto. Although the utility model is described in detail with reference to the above embodiments, those skilled in the art should understand that any technician familiar with the technical field can still modify the technical solution recorded in the above embodiments within the technical scope disclosed by the utility model, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solution of the embodiment of the utility model, and should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model shall be based on the protection scope of the claims.

Claims

1. An energy storage device in a pitch control system, characterized in that: The energy storage device includes a supercapacitor module and a battery pack; The supercapacitor module and the battery pack are respectively connected to a rectifier circuit, and the rectifier circuit is connected to a power grid; the rectifier circuit is also connected to an inverter circuit, and the inverter circuit is connected to a pitch motor in the pitch system; When the grid supplies power, the electric energy is rectified by the rectifier circuit to charge the supercapacitor module and the battery pack; when the grid stops supplying power, the supercapacitor module or the battery pack feeds back electric energy to the grid.

2. The energy storage device according to claim 1, characterized in that: The energy storage device further includes a first DC / DC voltage conversion circuit; the first DC / DC voltage conversion circuit is arranged between the rectifier circuit and the battery pack; The first DC / DC voltage conversion circuit is used to charge the battery pack after converting the input electric energy into a first specified voltage.

3. The energy storage device according to claim 2, characterized in that: The rectifier circuit includes a plurality of; The battery pack is connected to one of the plurality of rectifier circuits via the first DC / DC voltage conversion circuit.

4. The energy storage device according to claim 2, characterized in that: The first DC / DC voltage conversion circuit includes a BUCK circuit, one end of the BUCK circuit is connected to the bus bar, and the other end of the BUCK circuit is connected to the battery pack.

5. The energy storage device according to claim 1, characterized in that: The energy storage device further includes a boost circuit; the boost circuit is arranged between the battery pack and the rectifier circuit; The boost circuit is used to boost the electric energy provided by the battery pack and input it into the rectifier circuit, and after inversion by the rectifier circuit, input the inverted electric energy into the power grid.

6. The energy storage device according to claim 5, characterized in that: The boost circuit comprises a Boost circuit; one end of the Boost circuit is connected to the battery pack, and the other end of the Boost circuit is connected to the rectifier circuit.

7. The energy storage device according to claim 1, characterized in that: The energy storage device further includes a second DC / DC voltage conversion circuit; the second DC / DC voltage conversion circuit is arranged between the rectifier circuit and the super capacitor module; The second DC / DC voltage conversion circuit is used to charge the supercapacitor module after converting the input electric energy into a second specified voltage.

8. The energy storage device according to claim 7, characterized in that: The second DC / DC voltage conversion circuit includes a BUCK circuit; one end of the BUCK circuit is connected to the bus, and the other end is connected to the supercapacitor module.

9. The energy storage device according to claim 1, characterized in that: The energy storage device also includes a discharge branch of the supercapacitor module; a diode device is provided on the discharge branch; One end of the discharge branch is connected to the supercapacitor module, and the other end is connected to the rectifier circuit.

10. The energy storage device according to claim 1, characterized in that: The supercapacitor module and the battery pack are connected to the same DC / DC circuit; the DC / DC circuit is provided with an on-off control device; The on-off control device includes a first connection point and a second connection point; the first connection point is connected to the battery pack and the super capacitor module at the same time; the second connection point is connected to the super capacitor module; When the on-off control device is connected to the first connection point, the battery pack and the supercapacitor module are charged simultaneously; When the on-off control device is connected to the second connection point, the supercapacitor module is charged.

11. A variable pitch system, characterized in that: The pitch system comprises a rectifier circuit, an inverter circuit, a pitch motor and an energy storage device in the pitch system according to any one of claims 1 to 10; The energy storage device is connected to the rectifier circuit; the rectifier circuit, the inverter circuit and the pitch motor are connected in sequence.

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