Estimations of magnetic core loss are of great interest to power electronics engineers and magnetic material scientists. However, conventional measurement methods, like four-wire and calorimeters are typically not accurate at high frequency, or are too complicated and time consuming.
A CPES research team has developed a series of new methods to measure high-frequency magnetic core loss that are simple, fast, accurate and adaptive for any excitation waveform and dc flux level. The new methods compare the core being tested with air core by using reactive cancellation concept, explains Mingkai Mu, a Ph.D. student who invented these methods. “Since the air core is lossless,” he says, “the difference in the two cores represents the loss for the core being tested.”
The measurement accuracy of the new method is more robust with phase discrepancy, which is the major problem for high-frequency core loss measurement, he notes. The new methods are appropriate for high frequency (1 MHz–100 MHz, or even higher) measurement. “With these new methods, core loss for different flux waveforms can be accurately measured and many magnetic phenomena and models can be verified,” he says. The new methods can be the standard methods for high-frequency magnetic materials loss characterization, and be built as high-accuracy measurement instruments.”