Inductor and transformer losses are always important concerns for power electronics applications. The converter is less efficient without proper magnetic cores. Point-of-load (POL) converters are pushing for higher switching frequency for integration purposes. Accurate measurements of the loss of these passive components are important to their design. Accurately measuring the magnetic loss in high frequency magnetic materials is an important and urgent problem for materials science research. In this invention, different kinds of measurement methods are proposed to accurately measure the core loss and total loss of inductor/transformer.
The conventional transformer type method is not accurate when the measuring frequency is high, due to its sensitivity to phase discrepancy. At high frequency, severe errors will be introduced by small phase discrepancies caused by parasites, probe mismatch and oscilloscope resolution limitation. At several mega-Hertz, the error can be larger than 100%. Two new methods are invented to overcome this drawback. Both methods reduce the sensitivity to phase discrepancy, and separate the core loss from the winding loss. The first method is suitable for sinusoidal excitation. The second method can measure the loss for arbitrary excitation. With slight modifications, the new methods can measure the loss of an inductor/transformer at any given excitation condition. In summary, the new methods are very suitable to measure the loss of high frequency inductor/transformer used in power electronics applications, and analyze the loss of high frequency magnetic materials.