Permanent magnet biased magnetic element assembly and method for implementing same

Abstract

The invention provides a permanent magnet biased magnetic element assembly which comprises a first group of magnetic circuits, a second group of magnetic circuits, excitation coils and at least one permanent magnet connecting magnetic circuit. The first group of magnetic circuits and the second group of magnetic circuits comprise magnetic circuits with low magnetic resistance and magnetic circuits with low magnetic resistance, and the excitation coils are respectively arranged on the two groups of magnetic circuits; the permanent magnet connecting magnetic circuits are connected with the two groups of magnetic circuits; the direction of permanent magnetic flux generated by permanent magnets on magnetic cores of the first group of magnetic circuits and magnetic cores of the second group of magnetic circuits is opposite to the direction of direct-current magnetic flux generated by the excitation coils on the magnetic cores of the first group of magnetic circuits and the magnetic cores of the second group of magnetic circuits owing to arrangement of the positions and the polarity of the permanent magnets. The permanent magnet biased magnetic element assembly has the advantages that the direct-current magnetic flux generated by direct-current portions of flowing currents which flow through magnetic element windings can be offset by the permanent magnetic flux generated by the permanent magnets, alternating-current magnetic flux generated by alternating-current components of the flowing currents in the magnetic element windings can be prevented from cutting the permanent magnets, accordingly, the volumes of magnetic core materials in magnetic elements can be diminished, or working currents of the magnetic elements can be increased, and the permanent magnets can be basically guaranteed against eddy current loss of alternating-current magnetic flux.

Description

technical field [0001] The invention relates to a magnetic element assembly with permanent magnetic bias and its realization method. Background technique [0002] Power magnetic components 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 DC bias flux density, the problem of magnetic core saturation also follows, which in turn causes a decrease in inductance. In order to solve the above problems, people apply permanent magnet materials to power inductors, hoping to use the magnetic field generated by the permanent magnet materials to offset the bias caused by the DC part of the current flowing through the inductor coil. [0003] Existing technology 1 such as figure 1 As shown, the permanent magnet material is placed in the air gap of the magnetic core (the air gap can be fi...

AI Technical Summary

Problems solved by technology

However, although the biasing capacity of bonded permanent magnets is higher than that of ferrite permanent magnets, it is much lower than that of rare earth sintered permanent magnets, and it is difficult to obtain good results.

If a sintered permanent magnet with good permanent magnetic performance is used, in order to reduce the eddy current loss of the permanent magnet, it is necessary to reduce and eliminate the AC flux entering the permanent magnet, which requires structurally designing the permanent magnet magnetic circuit so that its reluctance is greatly increased. Greater than (at least 5 times) the air gap reluctance can effectively reduce the AC excitation flux entering the permanent magnet magnetic circuit, thereby reducing and avoiding the eddy current loss in the permanent magnet, but this affects the design and actuality of the permanent magnet magnetic circuit applications, also add extra volume

[0005] The disadvantage of the above two technologies is that a large eddy current effect will be generated in the permanent magnet, resulting in an increase in loss and temperature, which may cause demagnetization failure and eventually lose its effect

Causes the core of the magnetic component to saturate during operation, and the performance deteriorates

[0006] The above problems are due to the fact that the permanent magnet is placed in the middle or next to the air gap of the magnetic element, and the high-frequency alternating current flowing in the winding of the magnetic element will generate a high-frequency alternating magnetic field. In the above two technologies, this high-frequency magnetic field is inevitable The permanent magnet is cut to cause the above phenomenon

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