Model Predictive Control Using Joint Voltage Vector for Quasi-Z-Source Inverter With Ability of Suppressing Current Ripple

To reduce the inductor current ripple and the output current error of quasi-
$Z$
-source inverter (qZSI) and simplify the design work of weighting factor in model predictive control (MPC), this article presents a novel MPC method using joint voltage vector (VV) for the qZSI. Unlike the convention MPC that applies one VV in one control cycle, the proposed method employs a shoot-through (ST) VV, a null VV, and an active VV as a joint VV to approach objective VV that can produce expected qZSI performance. The ST VV and the null VV are directly applied without the cost function evaluation. By calculating the duty ratios of the two VVs, the dead-beat control for the inductor current and the active VV amplitude control for the output current are achieved. Therefore, the inductor current ripple and the output current error can be reduced. Furthermore, a precise and quick active VV selection method is given for the optimal active VV selection, and hence the computation burden of the proposed method is decreased with significance. The performance of the proposed method is analyzed and compared with the similar MPC method. The experimental results verify the validity and the advantages of the proposed method.