DE20110520U1 - Lossless generator for use in power generation in wind turbines - Google Patents

Description

Description: State of the art:

Conventional generators with gears are currently used to convert wind energy into electricity, but also permanent magnet generators, some of which are also used without gears. When using generators with _gears , a relatively poor overall efficiency must be accepted, which plays a decisive role in wind turbines. In larger systems (greater than 100 kW), the generator efficiency is good, but the gearbox efficiency is poor due to the necessary high transmission ratio. In smaller systems, the efficiency of the generator is low.

The generator efficiency is getting worse, but the gearbox efficiency losses are no longer as dominant.

An additional problem is the poor start-up of the systems, especially in cold weather, as the gear oil is still very viscous and severely hinders the start-up of the systems when there is little wind.

Permanent magnet generators, especially directly driven ring generators, have the advantage of being more efficient than conventional generator/gearbox solutions in wind turbines, but here too, remagnetization losses occur in the laminated core, since the winding has to be inserted into a stator laminated core.

An additional problem with conventional permanent magnet generators is "locking" because the magnets always try to align themselves with the stator teeth. Here too, the generator must first be "josbroken", which is a problem especially when there is little wind. The systems only start up at higher wind speeds or must be electrically "started" when there is little wind.

Problem:

The invention specified in the protection claim is based on the problem of designing a generator for wind turbines which has a very high efficiency and which does not have to be "broken" as described above.

Solution:

This problem is solved by using an "iron loss-free" generator which corresponds to the features listed in the present claim^-——

Benefits achieved:

Since, as shown in Figure 1, no stator core is required, the remagnetization losses in the core (iron losses) are eliminated. This is particularly important because the iron losses increase with increasing speed, whereas the copper losses are independent of the speed. This is achieved by moving the iron return together with the magnets, with the copper winding between the magnets and the iron return.

First advantage: The winding can be cooled very well because it is free-standing. The resulting waste heat is not first transferred to the laminated core in which the winding is inserted, as is the case with a conventional motor (generator). This reduces copper losses compared to a conventional motor (generator). The winding stays cooler with the same output.

A second, decisive advantage is that the possible current in the winding is not limited by the saturation induction of the stator lamination (iron core).
This allows very high torques to be achieved, which can be crucial for a directly driven (gearless) wind turbine, for example:

• power can be extracted even at very low speeds.

• the generator can be used as a second braking system (with braking resistance) due to its very high potential torque.

A third, very important advantage is that this type of generator, unlike other permanent magnet generators, has no cogging torque. This is due to

crucial for starting the wind turbine in light winds. The wind turbine then does not have to be "broken" from its standstill position. It starts up at the slightest breeze, which is particularly important for H-Darrieus turbines, as conventional models have very poor starting behavior in light winds.

Claims (1)

Use of an "iron loss-free" generator for installation in wind turbines characterized by
that magnets ( 1 ) are mounted on a magnet carrier ( 2 ) which is attached to a rotor support plate ( 3 ) as well as the iron return plate ( 4 ) (rotating)
characterized,
that a copper winding ( 5 ) is mounted on a stator support plate ( 6 ), which in turn is mounted on a mounting ( 7 ) (standing)
characterized,
that there is a bearing ( 8 ) between the rotating part (rotor) and the stationary part (stator).