new control method for the series resonant converter
(SRC) in which the device switching instants are always synchronized
to the zero crossing points of the resonant current is proposed. Output
voltage is controlled by proper selection of the switch modes by varying
the duty ratio of powering mode and free resonant mode. Each switch
mode is analyzed and the dc transfer function is obtained. It is also
shown that the simulation results coincide well with the practical case.
The SRC with the proposed control scheme shows many advantages,
such as low current switching stress, low switching loss, low electromagnetic
interference, high input power factor, and wide control range.
Some of these characteristics are verified experimentally.