Double-stator permanent magnet brushless doubly-fed wind generator

Abstract

The invention discloses a double-stator permanent magnet brushless doubly-fed wind generator. An outer stator (2) and an inner rotor (4) are arranged on the outer circumference and the inner circumference of an outer rotor (3) respectively, and an inner stator (5) is arranged on the inner circumference of the inner rotor (4); the outer rotor (3) and the inner rotor (4) are coaxial and can freely rotate; the outer stator (2) is provided with a p-antipode power winding (21) and is connected with a power grid directly; the inner stator (5) is provided with a q-antipode control winding (51) and is connected with the power grid through an AC-DC-AC power converter; the inner surface and the outer surface of the outer rotor (3) are each provided with p pairs of permanent magnets (31); the inner rotor (4) is a magnetism modulation ring provided with p+q magnetic conductive blocks, magnetic fields generated by the permanent magnets (31) are modulated by the inner rotor (4), and then excitation magnetic fields can be provided for the control winding (51). The permanent magnet excitation is adopted in the double-stator permanent magnet brushless doubly-fed wind generator, so the power density of the doubly-fed wind generator is improved; magnetic gears are additionally arranged and a mechanical step-up gear box is eliminated, and therefore reliability is improved; relatively smaller harmonic magnetic fields of the permanent magnets are used for excitation for the small-power control winding.

Description

technical field [0001] The invention relates to the field of wind power generation equipment, in particular to a double-stator permanent magnet brushless double-fed wind power generator capable of realizing variable speed and constant frequency. Background technique [0002] Wind energy is a clean and renewable energy source. Vigorously developing renewable energy power generation technologies including wind power generation is the best choice to solve the global energy and resource shortage. Wind turbines generally use synchronous or induction generators. Grid-connected wind turbines require the output frequency of the generator to be consistent with the grid frequency. Since traditional synchronous or induction generators cannot achieve variable speed and constant frequency operation, the utilization rate of wind energy is relatively low. . Therefore, variable-speed constant-frequency wind turbines that can overcome the above-mentioned shortcomings have developed rapidly...

AI Technical Summary

Problems solved by technology

However, the shortcomings of this kind of generator are also quite obvious: due to the existence of the main winding and the excitation winding, the volume of the motor with the same capacity is relatively large, and the efficiency is also low; It is necessary to use a speed-increasing gearbox, which increases the mechanical loss of the unit, noise pollution and maintenance workload; there is an excitation winding on the rotor, which requires slip rings and brushes, which reduces reliability and increases maintenance workload.

The direct-drive permanent magnet synchronous generator cancels the speed-increasing gearbox, the rotor has no winding, no slip rings and brushes are required, which improves reliability, reduces maintenance workload, and has high efficiency. However, the direct-drive permanent magnet synchronous generator itself Huge in size and weight, requires a full-power power converter, and high in cost

[0003] In recent years, magnetic gear technology has developed rapidly, and a permanent magnet brushless wind turbine with a magnetic gear outer rotor has appeared, which can greatly reduce the number of pole pairs of permanent magnet synchronous motors, reduce the volume of the generator, but also increase the generator capacity. The structural complexity, and also requires a full-power converter, the cost is very high

The permanent magnet utilization rate of the magnetic gear is low, which increases the amount of permanent magnet material and further increases the cost

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