Modeling, Analysis and Proportional Resonant and Proportional Integral Based Control Strategy for Single Phase Quasi-Z Source Inverters

Abstract

This paper proposes a proportional resonant and proportional integral based control strategy for single phase quasi-Z-source inverters (qZSIs) which is able to operate in buck and boost modes. Switching signals of the qZS inverters can be generalized as shoot through and non-shoot through states. The DC-link voltage of the qZSIs can be controlled by generating proper shoot through signals. The control strategy for qZSIs should be able to control both DC and AC-sides at the same time. First, the average state–space model of qZSI is obtained for closed loop control in this paper. Thereafter, the proportional resonant control is designed to achieve AC-side voltage control. Also, voltage control of DC-side capacitor is achieved by using proportional integral control method. Finally, the switching signals are obtained by applying the control outputs to modulation strategy. Experimental results are presented to demonstrate the effectiveness of the control method. The results verify that the proposed control strategy successfully regulates both DC and AC-side control variables.

Keywords

• PI controller
• PR controller
• sinusoidal pulse width modulation
• quasi-Z-source inverter