Comparison of Critical Conduction Mode, Triangular Current mode and Pulse Width Modulation for MHz GaN based H-bridge Boost PFC

摘要

This paper explains about three controltechniques for MHz Galium Nitride (GaN) based H-bridgePower factor corrector (PFC) and compares them on the basisof efficiency. The first technique- Critical conduction mode(CRM) is widely used for PFC as the input current follows theinput voltage and Zero voltage switching (ZVS) turn-on of themain switch is achieved for most of the period with thedrawback of variable switching frequency. The second controlmethod- Triangular current mode (TCM) proposed byMarxgut,C. et. al. [1] is claimed to be more efficient when themains voltage is greater than half of the dc bus voltage oversome period of the mains cycle. For PFC operation thedifference of the on time and the reverse recovery time shouldbe constant, if on time and reverse recovery time are keptconstant separately this also results in a variable switchingfrequency. The third technique is derived from TCM) in whichthe on time and the reverse recovery time are varied so that theswitching frequency is constant and the average input currentalso follows the input voltage. This technique is similar to PulseWidth Modulation (PWM).