Electric excitation double-fed wind driven generator for frequency division power transmission system

Abstract

The application discloses a kind of electric excitation doubly-fed wind-driven generators for frequency division power transmission system, including stator and rotor, stator is sleeved on rotor, and there is air gap between stator and rotor;The rotor includes rotor core and rotor excitation winding, and a plurality of rotor teeth are provided on the outside of the rotor core, and the rotor excitation winding includes 50 / 3 hertz excitation winding and 50 hertz excitation winding, and the 50 / 3 hertz excitation winding and the 50 hertz excitation winding are wound on the rotor tooth respectively;The stator includes stator core and stator armature winding, and a plurality of stator teeth are provided on the inside of the stator core, and the stator armature winding includes 50 / 3 hertz armature winding and 50 Hz armature winding, and the 50 / 3 hertz armature winding and the 50 Hz armature winding are wound on the stator tooth respectively, the generator can emit 50 / 3 hertz and 50 hertz electric energy respectively, and has the characteristics of high economy, high operation reliability and superior performance.

Description

Technical Field

[0001] This invention belongs to the field of new energy and power engineering technology, and relates to a doubly fed wind turbine generator for frequency division transmission system. Background Technology

[0002] Wind turbines, as the conversion unit between wind energy and electrical energy, are one of the core components of frequency-division transmission systems. Currently, scholars have studied the types of generators suitable for frequency-division transmission systems, and the results show that traditional low-speed direct-drive permanent magnet generators can be used in these systems. However, when traditional direct-drive permanent magnet generators are connected to the grid, a full-power inverter is required for rectification and inversion to output stable 50 / 3 Hz AC power. For high-power offshore wind turbines, the required inverter capacity and cost are enormous. Furthermore, when traditional direct-drive permanent magnet wind turbines are used in frequency-division transmission systems, they can only generate 50 / 3 Hz power, while the power plant's power system requires 50 Hz power. To meet the needs of the plant's power system, additional frequency converters are usually required, further increasing the cost of the frequency-division transmission system. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide an electrically excited doubly fed wind turbine generator for frequency division transmission systems. This generator can generate 50 / 3 Hz and 50 Hz electrical energy respectively, and has the characteristics of high economy, high operational reliability and superior performance.

[0004] To achieve the above objectives, the present invention discloses an electrically excited doubly fed wind turbine generator for a frequency division transmission system, comprising a stator and a rotor, wherein the stator is sleeved on the rotor and there is an air gap between the stator and the rotor;

[0005] The rotor includes a rotor core and a rotor excitation winding. Several rotor teeth are provided on the outer side of the rotor core. The rotor excitation winding includes a 50 / 3 Hz excitation winding and a 50 Hz excitation winding, which are respectively wound on the rotor teeth.

[0006] The stator includes a stator core and a stator armature winding. The inner side of the stator core is provided with a plurality of stator teeth. The stator armature winding includes a 50 / 3 Hz armature winding and a 50 Hz armature winding, which are respectively wound on the stator teeth.

[0007] The 50 / 3 Hz armature winding is wound on the stator teeth in a three-phase symmetrical winding structure. During operation, the 50 / 3 Hz armature winding generates a fundamental magnetic field with p pole pairs, where p is a positive integer.

[0008] The 50Hz armature winding is wound on the stator teeth in a three-phase symmetrical winding structure. During operation, the 50Hz armature winding generates a fundamental magnetic field with 3p pole pairs.

[0009] During operation, a DC current is applied to the 50 / 3 Hz excitation winding and the 50 Hz excitation winding. The 50 / 3 Hz excitation winding generates an excitation magnetic field with p pole pairs, and the 50 Hz excitation winding generates an excitation magnetic field with 3p pole pairs.

[0010] The 50 / 3 Hz armature winding interacts with the excitation magnetic field of the p-pair in the air gap to generate alternating current with a frequency of 50 / 3 Hz.

[0011] The 50Hz armature winding interacts with the excitation magnetic fields of the p-pair and 3p-pair in the air gap to generate alternating current with a frequency of 50 Hz.

[0012] Rotor slots are formed between adjacent rotor teeth. The 50 / 3 Hz excitation winding and the 50 Hz excitation winding are both located in the rotor slots and are distributed sequentially from the inside to the outside.

[0013] Stator slots are formed between adjacent stator teeth. The 50 / 3 Hz armature winding and the 50 Hz armature winding are located in the stator slots and are distributed sequentially from the inside to the outside.

[0014] The present invention has the following beneficial effects:

[0015] In the specific operation of the frequency-divided power transmission system using the doubly-fed induction generator described in this invention, the rotor excitation winding includes a 50 / 3 Hz excitation winding and a 50 Hz excitation winding; the stator armature winding includes a 50 / 3 Hz armature winding and a 50 Hz armature winding. During operation, it generates 50 / 3 Hz electrical energy and 50 Hz electrical energy respectively. The 50 / 3 Hz electrical energy can be directly transmitted to the frequency-divided power transmission grid, thereby eliminating the need for an intermediate frequency converter and improving the economy and reliability of the frequency-divided power transmission system. The 50Hz power can be connected to the frequency-divided power grid via a frequency converter, and simultaneously directly connected to the power plant's auxiliary power system, thus eliminating the need for a frequency converter between the wind turbine and the power plant. This further improves the economy and operational reliability of the entire system, resulting in superior performance. Furthermore, this invention only requires control of the 50Hz armature winding to adjust and control the wind turbine's operating status, simplifying the control system and further enhancing the overall system's economy and reliability. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0017] Figure 2 This is a schematic diagram of the rotor 2 in this invention;

[0018] Figure 3 This is a schematic diagram of the structure of stator 1 in this invention;

[0019] Figure 4 This is a diagram showing the harmonic content of the radial component of the unloaded air gap magnetic flux density in this invention.

[0020] Figure 5 This is the back electromotive force diagram of the 50 / 3 Hz armature winding 6-1 in this invention;

[0021] Figure 6 This is the back electromotive force diagram of the 50Hz armature winding 6-2 in this invention.

[0022] Wherein, 1 is the stator, 2 is the rotor, 3 is the rotor core, 4 is the rotor excitation winding, 4-1 is the 50 / 3 Hz excitation winding, 4-2 is the 50 Hz excitation winding, 5 is the stator core, 6 is the stator armature winding, 6-1 is the 50 / 3 Hz armature winding, and 6-2 is the 50 Hz armature winding. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, not all embodiments, and are not intended to limit the scope of the present invention. Furthermore, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion regarding the concepts disclosed in the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.

[0024] The accompanying drawings show structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not drawn to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0025] refer to Figure 1 The frequency division power transmission system of the present invention includes a stator 1 and a rotor 2. The stator 1 is sleeved on the rotor 2, and there is an air gap between the stator 1 and the rotor 2.

[0026] The rotor 2 includes a rotor core 3 and a rotor excitation winding 4. Several rotor teeth are provided on the outer side of the rotor core 3, wherein a rotor slot is formed between adjacent rotor teeth, and the rotor excitation winding 4 is wound on the rotor teeth and is located inside the rotor teeth.

[0027] The stator 1 includes a stator core 5 and a stator armature winding 6. The inner side of the stator core 5 is provided with a plurality of stator teeth, wherein stator slots are formed between adjacent stator teeth, and the stator armature winding 6 is wound on the stator teeth and is located in the stator slots.

[0028] refer to Figure 1 and Figure 3 The stator armature winding 6 includes a 50 / 3 Hz armature winding 6-1 and a 50 Hz armature winding 6-2. The 50 / 3 Hz armature winding 6-1 is wound on the stator teeth in a three-phase symmetrical winding structure. During operation, the 50 / 3 Hz armature winding 6-1 generates a fundamental magnetic field with p pole pairs. The 50 Hz armature winding 6-2 is wound on the stator teeth in a three-phase symmetrical winding structure. During operation, the 50 Hz armature winding 6-2 generates a fundamental magnetic field with 3p pole pairs, where p is a positive integer. The 50 / 3 Hz armature winding 6-1 and the 50 Hz armature winding 6-2 are located in the stator slots and are distributed sequentially from the inside to the outside.

[0029] refer to Figure 1 and Figure 2 The rotor excitation winding 4 includes a 50 / 3 Hz excitation winding 4-1 and a 50 Hz excitation winding 4-2. During operation, a direct current is supplied to the 50 / 3 Hz excitation winding 4-1 and the 50 Hz excitation winding 4-2. The 50 / 3 Hz excitation winding 4-1 generates an excitation magnetic field with p pole pairs, and the 50 Hz excitation winding 4-2 generates an excitation magnetic field with 3p pole pairs. By adjusting the number of turns and the magnitude of the excitation current of the 50 / 3 Hz excitation winding 4-1 and the 50 Hz excitation winding 4-2, the content of the p-p pole magnetic field and the 3p pole magnetic field in the air gap can be adjusted. The direct current can be supplied through brushes and slip rings.

[0030] When the present invention is in operation, the 50 / 3 Hz armature winding 6-1 interacts with the excitation magnetic field of the p-p pair in the air gap to generate alternating current with a frequency of 50 / 3 Hz; the 50 Hz armature winding 6-2 interacts with the excitation magnetic fields of the p-p and 3p pairs in the air gap to generate alternating current with a frequency of 50 Hz.

[0031] Example 1

[0032] refer to Figure 1 In this embodiment, a generator with a fundamental magnetic pole pair of the air gap radial magnetic field is used as an example, i.e., p = 1.

[0033] refer to Figure 4 , Figure 4 The radial component harmonic content of the unloaded air gap magnetic flux density in this embodiment is determined by... Figure 4 It can be seen that the radial component of the air gap magnetic field generated by rotor excitation winding 4 mainly includes a fundamental magnetic field with one pair of poles and a harmonic magnetic field with three pairs of poles.

[0034] In this embodiment, the rated speed of rotor 2 is 1000 rpm. At this time, the 50 / 3 Hz armature winding 6-1 interacts with the excitation magnetic field of one pair of poles in the air gap to generate alternating current with a frequency of 50 / 3 Hz; the 50 Hz armature winding 6-2 interacts with the excitation magnetic fields of one pair and three pairs of poles in the air gap to generate alternating current with a frequency of 50 Hz.

[0035] Figure 5 and Figure 6 The back potential waveform diagram of the present invention is shown below. Figure 5 It can be seen that the output frequency of the 50 / 3 Hz armature winding 6-1 in this invention is a voltage with a frequency of 50 / 3 Hz, which is determined by... Figure 6 It can be seen that the output frequency of the 50Hz armature winding 6-2 is a voltage of 50 Hz, which can enable the two sets of stator windings to output electrical energy at different frequencies.

[0036] In summary, this invention can generate 50 / 3 Hz and 50 Hz electrical energy during operation. The 50 / 3 Hz energy can be directly transmitted to the frequency-division power grid, eliminating the need for an intermediate frequency converter and improving the economy and reliability of the frequency-division power transmission system. The 50 Hz energy can be connected to the frequency-division power grid via a frequency converter and can also be directly connected to the power plant's auxiliary power system, eliminating the need for a frequency converter between the wind turbine and the power plant, further improving the economy and operational reliability of the entire system. Furthermore, this invention only requires control of the 50Hz armature winding 6-2 to adjust and control the wind turbine's operating state, thus simplifying the control system and further improving the overall system's economy and reliability.

[0037] This invention patent uses an internal rotor motor model as an example, but other external rotor motors that conform to the principles described in this patent are also within the scope of protection of this patent.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A doubly-fed wind turbine generator for a frequency-division power transmission system, characterized in that, It includes a stator (1) and a rotor (2), with the stator (1) sleeved on the rotor (2) and an air gap between the stator (1) and the rotor (2); The rotor (2) includes a rotor core (3) and a rotor excitation winding (4). Several rotor teeth are provided on the outer side of the rotor core (3). The rotor excitation winding (4) includes a 50 / 3 Hz excitation winding (4-1) and a 50 Hz excitation winding (4-2). The 50 / 3 Hz excitation winding (4-1) and the 50 Hz excitation winding (4-2) are respectively wound on the rotor teeth. The stator (1) includes a stator core (5) and a stator armature winding (6). The stator core (5) has a plurality of stator teeth on its inner side. The stator armature winding (6) includes a 50 / 3 Hz armature winding (6-1) and a 50 Hz armature winding (6-2). The 50 / 3 Hz armature winding (6-1) and the 50 Hz armature winding (6-2) are respectively wound on the stator teeth. The 50 / 3 Hz armature winding (6-1) is wound on the stator teeth according to a three-phase symmetrical winding structure; during operation, the 50 / 3 Hz armature winding (6-1) generates a number of magnetic pole pairs. p The fundamental magnetic field of the opposite pole, wherein, p It is a positive integer; The 50 Hz armature winding (6-2) is wound on the stator teeth in a three-phase symmetrical winding structure. During operation, the 50 Hz armature winding (6-2) generates 3 magnetic pole pairs. p The fundamental magnetic field of the opposite pole.

2. The electrically excited doubly-fed wind turbine generator for a frequency division transmission system according to claim 1, characterized in that, During operation, a direct current is applied to the 50 / 3 Hz excitation winding (4-1) and the 50 Hz excitation winding (4-2). The 50 / 3 Hz excitation winding (4-1) generates a number of magnetic pole pairs. p The excitation magnetic field of the pole pair, the 50 Hz excitation winding (4-2) produces 3 pole pairs. p The excitation magnetic field of the opposite pole.

3. The electrically excited doubly-fed wind turbine generator for a frequency division transmission system according to claim 2, characterized in that, 50 / 3 Hz armature winding (6-1) and air gap p The excitation magnetic fields of the opposite poles interact to generate alternating current with a frequency of 50 / 3 Hz.

4. The electrically excited doubly-fed wind turbine generator for a frequency division transmission system according to claim 3, characterized in that, 50 Hz armature winding (6-2) and air gap p The pole and 3 p The excitation magnetic fields of the opposite poles interact to generate alternating current with a frequency of 50 Hz.

5. The electrically excited doubly-fed wind turbine generator for a frequency division transmission system according to claim 1, characterized in that, Rotor slots are formed between adjacent rotor teeth. The 50 / 3 Hz excitation winding (4-1) and the 50 Hz excitation winding (4-2) are both located in the rotor slots and are distributed sequentially from the inside to the outside.

6. The electrically excited doubly-fed wind turbine generator for a frequency division transmission system according to claim 1, characterized in that, Stator slots are formed between adjacent stator teeth. The 50 / 3 Hz armature winding (6-1) and the 50 Hz armature winding (6-2) are located in the stator slots and are distributed sequentially from the inside to the outside.

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