Shifting Paradigms: Z-Source Inverters as a Viable Solution for Enhanced DC-Link Regulation and Renewable Energy Integration

Shunt active power filter (SAPF) are often utilized to decrease current harmonics caused by nonlinear grid loads. Whenever the nonlinear loads are uneven, the grid currents corrected by SAPF are still deformed and unbalanced despite adopting efficient current detecting techniques. The justification for this is that the DC-link voltage will comprise a second-order harmonic whenever SAPF modifies the grid's unbalanced loads, which will have an impact on the SAPF's current control loop. Thus, the compensating ranges and effectiveness of SAPFs are directly impacted by DC-link voltage. However, conventional voltage source inverters (VSIs) used in SAPFs can face limitations in DC-link voltage regulation, especially when integrating renewable energy sources with fluctuating power output. This paper proposes exploring the potential of Z-source inverters (ZSIs) as an alternative solution. ZSIs offer inherent boost capability, which can be advantageous for maintaining stable DC-link voltage during renewable energy integration. This paper will discuss and analyze the transition from VSIs to ZSIs to achieve it for SAPFs, focusing on their impact on DC-link voltage regulation and PV solar integration. A comparative analysis of control strategies and circuit topologies for both inverter types will be presented to evaluate their performance and suitability for SAPF applications.