A Core Loss Calculation Method for DC/DC Power Converters Based on Sinusoidal Losses

Abstract

Traditional predicted core loss models, such as the improved Steinmetz equations, cannot show the whole changing tendency of core losses in different topologies. In this article, a core loss prediction model is presented based on sinusoidal losses. The axis of flux density is divided into a number of slice pairs in a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</i> - <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P_h</i> plane, and the hysteresis loss density is given in each slice pairs. By summing hysteresis losses associated with the actual swings of flux density in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</i> - <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P_h</i> plane, total hysteresis losses can be calculated quantitatively. This empirical approach is available both in calculating hysteresis losses under the centered and noncentered minor hysteresis loops. The effect of duty cycles on the swings of flux density and dc bias are analyzed, and two terms of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dc</sub> ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</i> ) and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k_Δ_B</i> ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</i> ) are identified to show their effects on hysteresis losses. Dynamic eddy current losses are mainly associated with exciting waveforms, which are indicated by introducing a term <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k_e</i> ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</i> ). Since the main features of power converters are characterized by three terms, the behaviors of core losses in various topologies can be described adequately. Experimental results from three typical power converters agree with theoretical analyses well.