A new configuration of seven-level quasi Z-source–based isolated inverter for renewable applications

Abstract

In this paper, a new configuration of seven‐level quasi Z‐source (qZs)–based isolated inverter is introduced in the family of Z‐source–based multilevel inverters (MLIs). The proposed topology is an upgrade of qZs inverter and asymmetrical seven‐level inverter with significant advantages of high boost gain, reduced device count, and higher efficiency. In addition, the front‐end qZs converter provides wide input voltage regulation for eco‐friendly photovol taic (PV) as well as fuel cell–based standalone/grid‐connected applications. The use of high‐frequency transformer blocks the leakage current from PV panels to the local load/grid, and the seven‐level inverter produces high quality sinu soidal output waveform, which reduces the filter size. Therefore, the working principle of the proposed configuration is tested in simulation, and an experi mental verification is performed to validate the effectiveness of the model. A proportional‐integral (PI) controller is designed in field‐programmable gate array (FPGA) using Xilinx blocks, and the dynamic response of the model is evaluated for changes in input voltage and step changes in load. Moreover, a brief comparative assessment of proposed configuration with existing seven level qZs‐MLI is also presented.