A Z-source inverter with switched network in the grid-connected applications

Abstract

Z-source inverters are essential to electrical power systems, renewable energy conversion, and numerous other industrial applications. The efficiency and performance of power systems can be improved by using them. Due to their single-stage buck-boost inversion ability and better immunity to EMI noise, research on Z-source inverters has recently been significantly intensified. As known, the immunity to EMI noise is important since affect circuits and prevent them from working correctly. However, their boost gains are restricted because of higher component-voltage stresses and poor output power quality. A new structure of switched network quasi Z-source inverter (SN-qZSI) is proposed to mitigate these drawbacks. The proposed inverter structure has a very high voltage boost gain at a low shoot through duty ratio and high modulation index to reduce the semiconductor stress. Also provides a better-quality output waveform. Furthermore, the proposed structure applies less voltage across its capacitors. Therefore, the installation cost, and weight can be reduced by using lower rating capacitors. Moreover, this suggested structure can also overcome the problem of starting inrush current. The proposed inverter's operating principle, steady-state analysis, and impedance parameter selections are presented. In addition, the proposed structure of the Z-source inverter is compared with other impedance-source inverters to highlight its features. Both simulation (Matlab/Simulink) and experimental results in a scaled-down prototype successfully validated the proposed theoretical analysis.