Impedance source inverter based ac-ac converter system

This paper presents a new topology of uninterruptible power supply
(UPS) by using a Z-source inverter, where a symmetrical LC network is employed to couple the main power circuit of an inverter to
a battery bank. Using passive diode rectifi er is known to constrain
the converter to operate in only the forward power transfer mode,
and generally support only voltage buck or boost operation, which
to some extent constrains its disturbance ride through ability. The
Z-source converter overcomes the conceptual and theoretical barriers and limitations of the traditional voltage-source converter and
current-source converter. The Z-source concept can be applied to
all dc-to-ac, ac-to-dc, ac-to-ac, and dc-to-dc power conversion. With
this new topology, the proposed UPS can maintain the desired ac
output voltage at the signifi cant voltage drop of the battery bank
with high effi ciency, low harmonics, fast response, and good steadystate performance. The entire system is simulated by MATLAB\
SIMULINK and the results are verifi ed experimentally.