by Viktor Vogman, Power Conversion Consulting, Olympia, Wash., How2Power Today, Jun 15 2021
Focus:
Hard switching in the single-ended forward converter topology limits the switching
frequency and restricts its usage up to a few hundred watts. Meanwhile, soft switching
increases circuit complexity, making other topologies with zero voltage switching (ZVS)
more popular at higher power levels. However, recent developments in SiC MOSFET and
bidirectional GaN switch technologies have created new opportunities for forward converter
design, simplifying implementation of ZVS and making the forward converter competitive
above 1 kW. This article studies opportunities and application benefits of employing such
devices in the forward converter. The topology described here uses a bidirectional switch
in place of the secondary-side rectifier diode and the buffer inductor. The operation of
this ZVS single-ended forward topology is explained and equations for key operating
parameters are presented. Configurations with multiple outputs and synchronous
rectification are also described.
What you’ll learn:
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