A Novel Model Predictive Control for Quasi Z-Source Inverter to Eliminate Negative Influence of Inductor Current Ripple on Output Current

The dead-beat control inherits the high control precision and the fast dynamic response of model predictive control (MPC). In many literatures, the dc-side current of the quasi Z-source inverter (qZSI) using the dead-beat control is regarded as an irrelevant variable to the ac-side current. In this article, a completely opposite conclusion about the relationship between the dc-side current and the ac-side current of the qZSI is given through the analysis of the output power and the inductor current error of the qZSI. The mechanism of how the inductor current of the qZSI affects the control accuracy of the output current is explored. The conclusion indicates that the control error in the average value of the inductor current leads to a deviation in the amplitude of the output current. To improve the control accuracy of the inductor current and the output current, a novel MPC is proposed for the qZSI. Based on the area method and the error symmetry principle, the average value of the inductor current in one control cycle can be equal to its reference value. Therefore, a complete match between the input power and the output power can ensure that the output current follows its reference very well. The experimental results confirm the effectiveness of the proposed method in improving the steady-state performance.