A brushless electric excitation low-speed generator suitable for low-wind-speed wind turbines

Abstract

The invention provides a brushless electro-magnetic low-wind-speed generator suitable for a low-speed wind turbine. The brushless electro-magnetic low-wind-speed generator comprises a main motor and an exciter, and the main motor and the exciter are arranged side by side along the axis of a rotating shaft. According to the brushless electro-magnetic low-wind-speed generator, a structure that the main motor and the exciter are coaxially combined is adopted, a slip ring electric brush device is omitted, and power distribution reliability of a system is improved; the main motor and the exciter are independent from each other in mechanical and magnetic structures and can be separated to carry out electromagnetic scheme design; an electro-magnetic mode is adopted in the motor, and compared with a permanent magnet generator, the brushless electro-magnetic low-speed generator has the advantages of being greatly reduced in cost; the problem of wind energy utilization on low-wind-speed areas is thoroughly solved.

Description

technical field [0001] The invention belongs to the field of generators, in particular to a brushless electric excitation low-speed generator suitable for low-wind-speed wind turbines. Background technique [0002] With the depletion of fossil energy, solar energy, wind energy, and biomass energy have broad application prospects in the new century as new green and environmentally friendly energy sources. With the gradual improvement of various practical technologies, such new energy sources will continue to be vigorously popularized. [0003] At present, in the field of new energy, wind energy utilization is the most popular, and its representative models are mainly medium and large wind turbines in the grid-connected mode. Very low, the rated speed is in the range of 20-30 revolutions per minute. But the rotating speed (1500 revolutions per minute) of its supporting generator all adopts small in size, light in weight high-speed generator. [0004] Therefore, in order to m...

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Problems solved by technology

However, the rotating speed of the generators (1500 revolutions per minute) are all small and light weight high-speed generators. This is because these components are all installed in the cabin in the air, and the reason for overweight is not allowed.

[0004] Therefore, in order to meet the high speed of the generator, a transmission with a very large speed ratio must be used in conjunction with it. Taking a wind turbine with a power of 1000 kilowatts and 20 revolutions per minute as an example, a generator with a power of 1500 revolutions per minute needs a transmission. The transmission ratio is 1:75, that is, the shaft of the wind turbine rotates once and the shaft of the generator rotates 75 times. The transmission with such a large ratio not only consumes a lot of power due to friction, but also generally consumes wind power. 1 / 3-1 / 4 of the total power of the machine shaft, and because the transmission ratio is too large, it leads to large volume, heavy weight, and the gears in the low-speed section are too stressed and often damaged, which is the main function of the wind turbine in operation. One of the flaws

[0005] If it is a 1500 kilowatt wind turbine, and the wind wheel is a wind turbine that rotates 17 times per minute, it is equipped with a 1500-rpm generator, then the transformation ratio will reach 1:89, that is, the main shaft of the wind turbine rotates once, and the main shaft of the generator needs to rotate 89 times. , the above-mentioned problems are even more serious, and it is easier to damage the

[0006] Four years ago, in terms of structural innovation of large-scale wind turbines, a permanent magnet direct drive low-speed generator without a transmission appeared. It is made of rare earth permanent magnets with strong magnetic force. Although the transmission is not used, but because the magnetic force of the rotor is too strong, the starting resistance of this generator is too large. Currently it is only suitable for use in high wind speed areas, because only in high wind speed areas Only in the wind speed area can the wind turbine obtain a large rotational torque, overcome the attraction of the permanent magnet rotor to the stator, and be able to start

[0010] The energy obtained by the wind turbine is proportional to the windward area of ​​the wind turbine, and is proportional to the third power of the wind speed. Therefore, the wind turbine with low wind speed also follows this law without exception, that is, the energy obtained by the wind turbine It is proportional to the third power of the wind speed. Therefore, when the wind speed decreases, the total output power also decreases with the law of the third power. Generally, it is unable to start at low wind speeds. This is because the wind turbine obtains The energy is very small and cannot overcome the starting resistance, and the traditional wind turbine has a large transmission with a large speed ratio, so the resistance is particularly large. Although the permanent magnet direct drive wind turbine does not have a transmission, the rotor used has a very strong magnetic force. It is made of rare earth magnets, so the magnetic attraction force of the rotor to the stator is particularly large, and it also shows that the starting resistance is huge, and it cannot start at low wind speeds.

[0011] When the wind speed is low, the energy is too small, so the current large wind turbines work in the high wind speed area (wind speed ≥ 10s / m, generally the rated wind speed range is 12-16s / m), and the wind speed less than 10s / m cannot be started at all. Because the starting resistance greatly exceeds the power obtained by the wind turbine at this wind speed

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