A measuring system and method for permanent magnet eddy current loss

Abstract

The invention relates to an eddy current loss measuring system and method of a permanent magnet. The system comprises a detector, a power amplifier, a differential amplification circuit and a digitalsignal processing unit; the detector comprises two U-shaped magnetic cores facing each other, excitation windings wound around magnetic poles of the U-shaped magnetic cores respectively, a magnetic core fixing support for fixing the magnetic cores, a position fixed support, a bottom support platform and a sample fixing support; the upper portion of the magnetic core fixing support is provided withgrooves which match the shapes of the magnetic cores, and the magnetic cores can be just fixed in the grooves respectively after winding of the excitation windings; the lower portion of the magneticcore fixing support is provided with a sliding groove; the sampling fixing support is fixed on the bottom support platform between the two U-shaped magnetic cores; and the excitation windings are connected in series and then connected to the digital signal processing unit via the power amplifier. Thus, the practical operation condition of the magnetic field of the motor can be simulated, the totalloss condition of the permanent magnet is reflected accurately, and the method is highly repeatable.

Description

technical field [0001] The invention relates to a novel eddy current loss detection device, in particular to a measuring system and method for the eddy current loss of a permanent magnet. Background technique [0002] At present, the research on the permanent magnet eddy current loss detection device is still in the blank stage, because the permanent magnet will demagnetize under the condition of heating, and the heating phenomenon of the permanent magnet in the permanent magnet motor is the key factor restricting the stable operation of the motor. Y.Aoyama et al. (Y.Aoyama, K.Miyata and K.Ohashi, "Simulations and experiments oneddy current in Nd-Fe-B magnet," IEEE Trans.Magnetics, vol.10, pp.3790-3792, 2005.) proposed Use the thermal resistance to test the temperature rise of the permanent magnet under the condition of external excitation to calculate its loss, but the thermocouple can only reflect the thermal effect at a certain point, and the distribution of the eddy curr...

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Problems solved by technology

Y.Aoyama et al. (Y.Aoyama, K.Miyata and K.Ohashi, "Simulations and experiments oneddy current in Nd-Fe-B magnet," IEEE Trans.Magnetics, vol.10, pp.3790-3792, 2005.) proposed Use the thermal resistance to test the temperature rise of the permanent magnet under the condition of external excitation to calculate its loss, but the thermocouple can only reflect the thermal effect at a certain point, and the distribution of the eddy current is uneven, and the heat distribution varies with the test position. And there is a big difference

The loss calculation of permanent magnets is based on the overall average effect, and the temperature rise measurement at a certain point cannot reflect the overall effect. In addition, the results of the temperature rise test will vary with the test environment, and there will be large errors

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