Grid-connected PV system based on a single-phase three-level qZS inverter

This paper describes the operation of a grid-connected PV system based on a single-phase 3L-NPC qZSI using PSCAD as simulation tool for modelling the system: PV array, single-phase 3L-NPC qZSI, filter stage and electrical grid. The control system considers a maximum power point tracking algorithm, a phase loop locked for synchronization with the grid voltage, a control strategy to inject current in phase with the voltage at the point of common coupling and the modulation technique that also take into account shoot-through duty cycle. Simulation results are provided in order to show the viability of using this topology for PV energy systems connected to the electrical grid.