Comprehensive Comparison of 99% Efficient Totem-Pole PFC with Fixed (PWM) or Variable (TCM) Switching Frequency

This paper presents a comprehensive comparison of a GaN-transistor based power factor correction in a totem-pole configuration – modulated on the one hand with pulse width modulation and on the other hand with triangular current mode. There are several different modulation schemes for the input current among which pulse width modulation and triangular current mode prove to be two of the most promising options in regard to overall efficiency. The basis for this comparison is a 180W front end with an AC input voltage of 230 V, 50 Hz and a DC output voltage which is varied between 360 V and 400 V. The experimental results demonstrate an efficiency at nominal power of 99% and greater. Focus of this paper is the comparison of the overall system efficiency when switching frequency, output voltage and size of the PFC inductor is varied with both modulation schemes. Power factor and total harmonic distortion of the current will be taken into account in order to ensure compatibility with applicable standards.