Magnetic element with permanent magnetic bias

Abstract

The invention relates to a magnetic element with permanent magnetic bias, which comprises a magnetic core which is used for forming a magnetic flux loop and provided with at least one air gap fracture. The magnetic element is characterized in that a working coil is wound on the magnetic core, at least one lateral surface of the air gap fracture of the magnetic core is provided with a pair of permanent magnets, the permanent magnets are provided with at least one soft magnetic core for communicating the two permanent magnets so as to form a permanent magnet containing magnetic branch connected in parallel with the air gap fracture, and the reluctance of the permanent magnet containing magnetic branch connected in parallel with the air gap fracture is more than 5 times as high as the reluctance of the air gap fracture of the magnetic element. The direct-current bias resistance of the magnetic core of the magnetic element can be effectively improved, the inductance under certain direct-current bias current is improved, or the section area of the magnetic core is reduced, and the volume is reduced or the length and electric resistance of the copper used for the working coil is reduced; and meanwhile, the defects that the traditional magnetic element with the permanent magnet is easy to be demagnetized by the current pulse and the eddy-current loss of the permanent magnet under the high-frequency flux causes temperature rise to result in failure of the permanent magnet at the high temperature.

Description

technical field [0001] The invention relates to a magnetic element with permanent magnetic bias, which is suitable for the situation where there is a relatively large DC (or low frequency) magnetic flux on the magnetic core of the magnetic element, and a relatively high frequency AC magnetic flux is superimposed. Background technique [0002] Magnetic components, especially power inductors, are widely used in various power converters, such as Boost inductors in PFC circuits, output filter inductors in DC / DC converters, output inductors in UPS, frequency converters and inverters, etc. However, with the increase of power and the increase of bias magnetic flux density, the core will be saturated, thereby reducing the inductance. In order to solve this problem and further improve the anti-magnetic saturation ability of power inductors, permanent magnet materials are applied to power inductors to use the biasing ability of permanent magnet materials to offset the bias caused by t...

AI Technical Summary

Problems solved by technology

The technical feature of the present invention is that the sintered rare-earth permanent magnet material with a small resistivity but a large bias capability can be used to improve the DC bias performance, and at the same time, through the design of the magnetic circuit reluctance structural parameters and the use of permanent magnets surrounded by magnetic circuits The short-circuit coil overcomes the problems that the sintered rare-earth material permanent magnet itself has a small resistivity due to the large eddy current loss caused by the high-frequency magnetic flux, which leads to the failure of the permanent magnet due to excessive temperature and the permanent magnet is easily demagnetized by the current pulse.

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