동적전압보상 기능을 갖는 출력이
직렬 결합된 Quasi Z-소스
AC-AC 컨버터
Quasi Z-Source AC-AC converter system
connected in series With Dynamic Voltage
Restorer(DVR) capability
Jun-Hyun Eom
Department of Electrical Engineering
Graduate, School Chonnam National University
(Supervised by Professor Young-Cheol Lim)
(Abstract)
Recently, different with the conventional load, the present load devices
such as computers, Automated production equipments, precision electronic
devices are very sensitive to the power quality. These load devices
sensitive to the power quality are increasing sharply and people are paying
more and more attention to the AC-AC power conversion devices like
instantaneous voltage-compensators, phase-shifters, electronic transformer
which are installed in the side of power system or consumers.
Similarly, the AC chopper, PWM AC-AC converter, matrix converter and
Z-Source AC-AC converter also belong to the AC-AC power conversion
devices referred above. among these devices, due to the latest research
method, the Z-Source AC-AC converter has quite simply structure and
control method and is possible to boost output voltage in phase and boost
or buck output voltage out of phase with respect to input voltage.
Nevertheless, since the Z-Source AC-AC converter operates in DCM
(Discontinuous Current Mode), stress of the elements is bigger compared
with the case of CCM(Continuous Current Mode) and it's very
disadvantageous viewed from the waveform.
It is probable to solve the problems referred above by Quasi Z-Source
AC-AC converter. However, the operation of buck mode is impossible, even
though it's possible to boost or buck the output voltage out of phase and
boost the output voltage in phase.
In this study, a single-phase quasi Z-source AC-AC converters with a
series connection of the output terminals is proposed.
The proposed system has configuration that the input terminals of two
quasi Z-source AC-AC converters are connected in parallel and its output
terminals are connected in series. for output of in-phase buck mode with
respect to the input ,the intersection switching control is presented and the
current flow in both of the out phase mode and in phase mode and the
output voltage's forming process was shown.
In addition, a DVR(Dynamic Voltage Restorer) though using a single-phase
quasi Z-source AC-AC converter connected with the output terminals in
series is proposed.
In general, among the problems which cause the lower quality, the
Voltage Swell or Voltage Sag could be the major one which brings great
influence to the consumers with high frequency and sensitive load. The
Voltage Swell which is the increasement of the supply voltage's magnitude
in duration of 0.5∼30[cycles] while the voltage magnitude is 1.1∼1.8[p.u]
of nominal voltage and the Voltage Sag which is the drop of the supply
voltage's magnitude in duration of 0.5∼30[cycles] while the voltage
magnitude is 1.1∼1.8[p.u] of nominal voltage can lead to the accidents
happening in most of the nearby distribution circuits. Such Voltage Swell or
Voltage Sag causes the misoperation or suspension of work and bring about
Nevertheless, since the Z-Source AC-AC converter operates in DCM
(Discontinuous Current Mode), stress of the elements is bigger compared
with the case of CCM(Continuous Current Mode) and it's very
disadvantageous viewed from the waveform.
It is probable to solve the problems referred above by Quasi Z-Source
AC-AC converter. However, the operation of buck mode is impossible, even
though it's possible to boost or buck the output voltage out of phase and
boost the output voltage in phase.
In this study, a single-phase quasi Z-source AC-AC converters with a
series connection of the output terminals is proposed.
LINK ORIGINAL EN LA WEB
http://ocean.kisti.re.kr/downfile/volume/kipe/JRJJC3/2013/v18n4/JRJJC3_2013_v18n4_322.pdf