Download Proposed System

Analysis and Modulation of the Buck-Boost
Voltage Source Inverter (BBVSI) for Lower
Voltage Stresses
ABSTRACT
Renewable energy sources entail the power electronics inverters are the orbit of research objectives for
optimum operation. Two commonly used inverters exist; the current source inverters (CSI) and the voltage source
inverters (VSI). The first one supports only the boost capability and the other supports the buck capability, but due
to the high variation of the output voltage of these renewable energy sources a buck boost capability is a must. This
buck-boost capability requires the enforcement of the aforementioned inverters with an additional stage for the
amendment of the energy source output, which greatly reduces the overall efficiency. Instead of such two stage
power conversion operation, a single stage operation could be obtained using the Z-source inverter (ZSI). The socalled ZSI exploits an impedance network to achieve such capability. This impedance network comprises four
passive elements and a semiconductor switch, which is relatively bulky and costly. This project proposes the
analysis and the modulation scheme of another inverter topology, called the buck-boost voltage source inverter
(BBVSI), to get the buck-boost capability in a single stage power conversion operation with less passive elements
and less semiconductor devices ratings. The BBVSI topology exploits only two passive elements in addition to a
semiconductor switch to give the same function of the ZSI with some merits over it. Moreover, this project
compares the BBVSI topology with the ZSI topology. The performance of the BBVSI topology is evaluated using
MATLAB/Simulink models.
CIRCUIT DIAGRAM
Existing System
In this project, the buck-boost voltage source inverter (BBVSI) topology, is studied, where the analysis and
the modulation of this topology is introduced to get the single stage power conversion operation property in addition
to less number of passive elements and less semiconductor switches ratings merits. This topology exploits only two
passive elements in addition to a semiconductor switch in its impedance network to achieve the property of single
stage power conversion operation unlike the other ZSI topologies mentioned before. Furthermore, higher boosting
ratio compared to the two stage power conversion operation based on the buck-boost DC-DC converter is obtained
as elucidated in the next section.
Proposed System
The BBVSI has the buck and boost capabilities, so it is a promising transformer less inverter topology. The
problem with the transformer less topologies is the lack of isolation between the DC side and the AC side. In the
simulation results showed before, the BBVSI is fed from a PV array. In any typical PV system, the PV modules are
grounded. This results in a capacitance to the ground, which depends on the climate conditions. Due to the high
switching frequency, a common mode voltage would exist on the load neutral point, and this could be solved using
several methods, which is out of the scope of this project, like common mode chokes, neutral point clamped
inverters, and reduced common mode voltage modulation techniques
TOOLS AND SOFTWARE USED:
 MP LAB

 ORCAD/PSPICE
 MATLAB/SIMULINK
OUTPUT:
 HARDWARE
 SIMULATION