A commercial ac-module topology is the
interleaved flyback converter, developed
by Enphase Energy [25] and currently
commercialized by Siemens, shown
in Figure 3. The flyback converter performs
MPPT and voltage elevation and
provides galvanic isolation while the
H-bridge inverter controls the dc-link
voltage (output voltage of the flyback),
grid synchronization, and active/reactive
power control. Several flyback converters
are connected in parallel, which
enables a higher switching frequency,
resulting in a further reduction of the HF
transformer and, hence, a very compact
inverter. It also allows for a reduction in
the current ripple both at the input and
output of the dc–dc stage due to the
phase-shifted carrier modulation, extending
the life span of the capacitors.