Abstract:
AC to DC rectifiers are used as front-end interface in multiple applications with DC load or
in inverter fed from line voltage. In applications with variable AC input voltage, rectifiers
with buck-boost capability are critical for achieving the most efficient power conversion.
The Z-source rectifier has been presented as the most suitable rectifier with buck-boost
performance. This dissertation introduces and analyses the quasi-Z-source rectifier as an
alternative efficient AC to DC converter with buck-boost capability. The model of the
quasi-Z-source rectifier is derived. The model of the Z-source rectifier is also derived with
an alternative approach. It is found from analytical results of the modelling that the quasi-Zsource
is a more cost-effective rectifier than the Z-source rectifier due to lower rated
capacitors. A two stages closed-loop controller for the quasi-Z-source rectifier is then
designed. Software simulations and hardware experiments of the quasi-Z-source rectifier are
performed and the results obtained confirm its efficient performances. This makes the quasi-
Z-source rectifier appropriate in renewable energy systems with AC voltage variations such
as wind power.
