Decoupling controller design for Z-source inverter

With the state-space averaging model and the proposed pulse-width modulation switching scheme, the Z-source inverter has been decoupled into a primary boosting stage and a secondary bucking stage. Two double-loop controllers are designed to handle the voltage regulation as well as the current regulation for the DC/DC and DC/AC conversion processes. The proposed scheme demands for two separate duty ratios and novel switching scheme has been derived to realise the combined duty ratios in one switching cycle. Power regulation, harmonics elimination and power factor correction control algorithms have also been derived for the Z-inverter when it is connected to the supply grid. Finally, experimental results are included to demonstrate the effectiveness of the proposed switching and control schemes.