Low-frequency doubly-fed wind turbine generator system

Abstract

The invention relates to a low-frequency doubly-fed wind turbine generator system. The low-frequency doubly-fed wind turbine generator system comprises a generator and a multi-port converter, a first port of the multi-port converter is connected with a stator side of the generator, a second port of the multi-port converter is connected with a rotor side of the generator, and a third port of the multi-port converter is connected with a low-frequency power grid; compared with the prior art, the double-fed wind turbine generator can directly output low-frequency electric energy, and the system is simple in structure and convenient to manufacture.

Description

Technical Field

[0001] The present invention relates to the field of new energy technology, and in particular to a low-frequency double-fed wind turbine system. Background Art

[0002] At present, new energy has been developed in clusters in the desert and deep sea. Its output fluctuates greatly. The channel utilization rate of the single-base island transmission method is low and the economy is poor. Wide-area networking at the transmission end will be an inevitable trend. Due to the weak grid, long electrical distance and charging reactive power restrictions, the industrial frequency AC networking capacity is severely limited. The DC networking method is difficult to transform and break faults and has high costs. Flexible low-frequency transmission technology has the characteristics of DC transmission capacity, strong flexibility and easy AC networking, which can support the wide-area networking of new energy base groups.

[0003] The existing wind turbines are mainly industrial frequency wind turbines, which need to be modified to directly output low-frequency electricity. Among them, direct-drive wind turbines can work in low-frequency power grids by adjusting filter parameters, controller parameters, and replacing transformers and GIS. However, since the stator side of the doubly-fed wind turbine is directly connected to the power grid, it is necessary to modify the generator, shaft and other components, which is complicated. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a low-frequency doubly-fed wind turbine system, which has the advantages of being able to directly output low-frequency electrical energy, having a simple structure and being easy to manufacture.

[0005] The above-mentioned inventive object of the present invention is achieved through the following technical scheme: a low-frequency doubly-fed wind turbine system, comprising a generator and a multi-port converter; the first port of the multi-port converter is connected to the stator side of the generator, the second port of the multi-port converter is connected to the rotor side of the generator, and the third port of the multi-port converter is connected to the low-frequency power grid.

[0006] Preferably, in the low-frequency doubly-fed wind turbine system provided by the present invention, the multi-port converter is based on an AC / AC polygonal converter.

[0007] Preferably, in the low-frequency doubly-fed wind turbine system provided by the present invention, the multi-port converter adopts an AC / DC-based multi-port converter.

[0008] Preferably, in the low-frequency doubly-fed wind turbine system provided by the present invention, the first port adopts a VF control method.

[0009] Preferably, in the low-frequency doubly-fed wind turbine system provided by the present invention, the second port adopts a maximum power point tracking control method.

[0010] Preferably, in the low-frequency doubly-fed wind turbine system provided by the present invention, the third port adopts a constant DC voltage control method.

[0011] Preferably, in the low-frequency doubly-fed wind turbine system provided by the present invention, the capacities of the first port and the third port are both set to the rated capacity of the system.

[0012] Preferably, in the low-frequency doubly-fed wind turbine system provided by the present invention, the capacity of the second port is set to 30% of the rated capacity of the system.

[0013] Preferably, in the low-frequency doubly-fed wind turbine system provided by the present invention, the generator is an asynchronous generator.

[0014] To sum up, the beneficial technical effects of the present invention are as follows: the low-frequency doubly-fed wind turbine system provided in the present application includes a generator and a multi-port converter; the first port of the multi-port converter is connected to the stator side of the generator, the second port of the multi-port converter is connected to the rotor side of the generator, and the third port of the multi-port converter is connected to the low-frequency power grid; compared with the prior art, the doubly-fed wind turbine system can directly output low-frequency electrical energy, and the system has a simple structure and is easy to manufacture. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 a in the figure is a schematic diagram of the overall structure of a low-frequency doubly-fed wind turbine system provided in an embodiment of the present invention.

[0016] Figure 1 FIG. b is a detailed diagram of a circuit module in a low-frequency doubly-fed wind turbine system provided in an embodiment of the present invention.

[0017] In the figure, 1. low-frequency doubly-fed wind turbine system; 10. generator; 20. multi-port converter; 21. circuit module. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0019] Reference Figure 1 , is a low-frequency doubly-fed wind turbine system 1 disclosed in the present invention, comprising a generator 10 and a multi-port converter 20; a first port of the multi-port converter 20 is connected to the stator side of the generator 10, a second port of the multi-port converter 20 is connected to the rotor side of the generator 10, and a third port of the multi-port converter 20 is connected to the low-frequency power grid; compared with the prior art, the doubly-fed wind turbine system 1 can directly output low-frequency electric energy.

[0020] Exemplarily, the generator 10 is an asynchronous generator.

[0021] Specifically, Figure 1As shown in a, XYZ is the first port, UVW is the second port, and ABC is the third port.

[0022] Exemplarily, the multi-port converter 20 may be an AC / AC polygonal converter. Of course, the multi-port converter 20 may also be an AC / DC-based multi-port converter. In the implementation method where the multi-port converter 20 is an AC / AC polygonal converter, the device usage requirements are reduced.

[0023] Furthermore, in this embodiment, according to the connection object of the multi-port converter 20, the first port adopts a VF control method (i.e., a voltage control method) to absorb the active power transmitted by the stator to the maximum extent. The second port adopts a maximum power tracking control method to adjust the output active power of the stator port according to the power curve of the wind turbine. The third port adopts a constant DC voltage control method to maintain the energy stability of the multi-port converter 20, thereby transmitting the power generated by the wind turbine to the low-frequency power grid, and then to the receiving-end converter.

[0024] The capacities of the first port and the third port are both set to the rated capacity of the system, and the capacity of the second port is set to 30% of the rated capacity of the system.

[0025] The multi-port converter 20 includes 9 bridge arms, which are connected in series in sequence. Each bridge arm includes a plurality of circuit modules 21, which are connected in series.

[0026] Reference Figure 1 In b, in this embodiment, the circuit module 21 includes an IGBT module Q1, an IGBT module Q2, an IGBT module Q3 and an IGBT module Q4, the IGBT module Q1 and the IGBT module Q2 are connected in series to form a first branch, the IGBT module Q3 and the IGBT module Q4 are connected in series to form a second branch, and the first branch and the second branch are connected in parallel.

[0027] The low-frequency doubly-fed wind turbine system 1 provided in the present application includes a generator 10 and a multi-port converter 20; the first port of the multi-port converter 20 is connected to the stator side of the generator 10, the second port of the multi-port converter 20 is connected to the rotor side of the generator 10, and the third port of the multi-port converter 20 is connected to the low-frequency power grid; compared with the prior art, the doubly-fed wind turbine system 1 can directly output low-frequency electrical energy, and the system has a simple structure and is easy to manufacture.

[0028] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0029] Finally, it should be noted that: Obviously, the above embodiments are only examples for clearly explaining the present invention, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the scope of protection of the present invention.

Claims

1. A low-frequency doubly-fed wind turbine system, characterized in that: including a generator and a multi-port converter; The first port of the multi-port converter is connected to the stator side of the generator, the second port of the multi-port converter is connected to the rotor side of the generator, and the third port of the multi-port converter is connected to the low-frequency power grid.

2. The low-frequency doubly-fed wind turbine system according to claim 1, characterized in that: The multi-port converter is based on an AC / AC polygonal converter.

3. The low-frequency doubly-fed wind turbine system according to claim 1, characterized in that: The multi-port converter adopts an AC / DC-based multi-port converter.

4. The low-frequency doubly-fed wind turbine system according to claim 1, characterized in that: The first port adopts a VF control method.

5. The low-frequency doubly-fed wind turbine system according to claim 1, characterized in that: The second port adopts a maximum power tracking control method.

6. The low-frequency doubly-fed wind turbine system according to claim 1, characterized in that: The third port adopts a constant DC voltage control method.

7. The low-frequency doubly-fed wind turbine system according to claim 1, characterized in that: The capacities of the first port and the third port are both set to the rated capacity of the system.

8. The low-frequency doubly-fed wind turbine system according to claim 7, characterized in that: The capacity of the second port is set to 30% of the rated capacity of the system.

9. The low-frequency doubly-fed wind turbine system according to claim 1, characterized in that: The generator adopts an asynchronous generator.

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