Control of space-vector modulated solar grid-tied quasi-Z-source Inverter

This paper proposes a control system design for quasi-Z-Source Inverter in photovoltaic grid-tied applications. The control system is designed based on the dynamical characteristics of the converter and comprises three cascaded controllers. Firstly, output current controller designed in the synchronous rotating frame. The second is DC-link voltage controller. Sampling and measurement of the DC-link voltage signal is discussed using modified space-vector modulation. The last is maximum power point tracking in which a new strategy is proposed to provide wide operating range of DC-link voltage and shoot-through duty ratio, minimize the voltage stress on the inverter bridge, and prevent overlap between shoot-through duty ratio and modulation index. Simulation results are presented to validate the controllers design.