Fig. 1. Core loss measurement circuit.

For power electronics application, non sinusoidal excitation like triangular AC flux with DC flux premagnetization on the inductor or transformer is most commonly encountered. So estimation of the magnetic core loss is very interesting for power electronics engineers, as well as magnetic material scientists. But conventional methods like CECC25300 and calorimeter is either not accurate enough when at high frequency or too complicated and time consuming. So a new method is proposed for the high frequency core loss measurement, which is simple, fast, accurate and for any excitation waveform and different DC flux level. The basic principle is to compare the core under test with air core. Due to air core is lossless, the two cores' difference is the core loss of the core under test. Such kind of setup makes the measurement accuracy is more robust to phase discrepancy. So this is good for high frequency (1MHz ~10MHz) measurement.

With this new method, core loss for different flux waveforms can be accurately measured and many magnetic phenomena and modeling can be verified.

Fig. 2. Left: Measurement waveforms (50% duty cycle rectangular voltage)

Right: Core loss of rectangular voltage excitation at different duty cycle (LTCC 200).