Permanent magnet excitation brushless doubly-fed wind turbine

Abstract

The invention discloses a permanent magnet excitation brushless doubly fed wind power generator. The permanent magnet excitation brushless doubly fed wind power generator comprises a stator (1), an outer rotor (2), an inner rotor (3) and a rotation shaft (6), wherein the stator (1) and the inner rotor (3) are respectively arranged on the periphery and the inner circumference of the outer rotor (2), the inner rotor (3) and the outer rotor (2) are coaxial and can freely rotate, two independent windings different in pole pair number are arranged on the stator (1), a power winding (8) of p pairs of poles is directly connected with a power grid, a control winding (9) of q pairs of poles is connected with the power grid through a direct and alternating power exchanger, the outer rotor (2) is a magnet ring regulation rotor with (p+q) magnetic conductive blocks, the inner rotor (3) is a q pair pole permanent magnet type rotor with a permanent magnet (7), and a permanent magnet field generated by the permanent magnet (7) generates magnet fields of the p pairs of the poles and the q pairs of the poles through magnet field modulating action of the outer rotor (2), and thereby provides excitation magnet fields respectively to the power winding (8) and the control winding (9). The permanent magnet excitation brushless doubly fed wind power generator uses permanent magnet excitation, increases the power density of an existing doubly fed wind power generator, and facilitates cost reduction of a wind power system.

Description

technical field [0001] The invention relates to the field of wind power generation equipment, in particular to a permanent magnet excitation 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 in...

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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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