Mathematical modeling of a hybrid magnetic gear for an autonomous low-power wind turbine

Abstract

In traditional wind turbines, a mechanical gearbox is used to transmit the torque. This device converts the low rotation speed of the wind turbine blades into the high rotation speed of the generator shaft. Mechanical gearboxes are characterized by low reliability. They consist of rotating gears, all the torque between which is transmitted through the contact of the teeth at one point, which is accompanied by friction. Magnetic multipliers are more efficient than gear reducers. They contain no wearing parts and have a relatively high torque density. The modulator transforms the magnetic field between the inner and outer rotor, due to which the speed of rotation changes. This device has a number of advantages over a mechanical gearbox - the interaction between rotating elements (torque transmission) occurs over their entire area, while the gears of mechanical gearboxes perceive all the transmitted force at one point of contact between them. Research of autonomous wind turbines built on the basis of magnetic gearboxes is a relevant direction. This will reduce operating costs, increase the efficiency of converting wind energy into electricity, and increase the reliability of the wind turbine as a whole. The purpose of the work is the development of a two-dimensional field mathematical model of a hybrid magnetic gearbox for the evaluation of its parameters and characteristics and the optimization of its geometric dimensions. A generator with a built-in magnetic multiplier is the object of this study. The magnetic multiplier during operation creates a rotating magnetic field that can be used to induce emf in the generator winding. Such a generator is more compact than a gear drive, so this option was chosen as a prototype in this study. Geometrical models of a hybrid generator with a magnetic gearbox were developed and numerical field mathematical models were developed for the analysis of its parameters and characteristics. An analysis of the electromagnetic field and characteristics of the basic generator was carried out in the COMSOL Multiphysics software complex, on the basis of which optimization of its geometric dimensions was carried out to optimize mass and dimensional indicators