Apparatuses for Iron Loss Measurement of Silicon Steel Sheets under Sinusoidal and PWM Waveforms
Date Issued
2009
Date
2009
Author(s)
Lai, Yi-Chih
Abstract
This thesis sets up the static test system to measure the magnetic properties of the silicon steel sheets. For the research, we build some common ring testers, a standard 25cm Epstein tester and an innovative structure applied to ring specimens. The test setup is used to measure silicon steel sheet properties critical for electrical motors and transformers design. The setup is capable of measuring the iron losses of silicon steel sheets under different of magnetizing waveform such as sinusoidal and Pulse-Width Modulation (PWM) waveforms. This thesis is divided into four parts: first, we build the common ring testers with three winding types and a 25cm Epstein tester with 0.5kg and 2kg specimen frames according to the ASTM standard. The test setup integrates the testers, a data acquisition card, a linear power amplifier, and a power meter into the static testing system. The second part of the thesis shows the experimental results under sinusoidal magnetizing waveforms that match with those from CSC measurement within the 50Hz~5kHz region. We also analyze the variations between different winding types. The system is able to extend the measuring bandwidth by applying induced voltage waveform control. The third part of the thesis builds a multi-function PWM inverter to enable iron loss measurement under the same operating condition as in an electric motor. The setup enables steel sheets magnetic properties measurement under non-sinusoidal excitations while maintaining the desired modulation waveforms and the carrier frequencies with different switching modes (unipolar and bipolar). Finally, this thesis proposes a new reusable ring type magnetic testing apparatus. The innovative tester permits easy exchange of the test specimens and provides a unified winding environment to eliminate any influences induced by winding irregularities. The unified testing condition then allows one to compare the more detailed and sensitive properties of different specimens.
Subjects
Iron loss
Silicon steel sheet
Ring tester
Epstein tester
Sinusoidal waveform
PWM
Innovative ring structure
Type
thesis
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