New hysteresis current control for grid connected single-phase three-level quasi-Z-source inverter

This paper proposes a new hysteresis current control technique for a grid connected single-phase three-level quasi-Z-source inverter. This control algorithm could be applied in any three-level inverter with Z- or quasi-Z-source network where reference current control signal along with shoot-through states is used. To explain the operation principle of the algorithm the steady state analysis is presented. As a result, the band ratio of the hysteresis current controller as a function of the input voltage and the preliminarily defined DC-link voltage were obtained. A simple closed loop control system for a grid connected inverter is described. Simulation results prove all theoretical predictions. Future applications are discussed.