Analysis and modulation of the buck-boost voltage source inverter (BBVSI) for lower voltage stresses

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 so-called 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 paper 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 paper compares the BBVSI topology with the ZSI topology. The performance of the BBVSI topology is evaluated using MATLAB/Simulink models.