Operation strategy and shoot-through indirect control method for three-phase Z-souree inverters

This paper proposes a new operation strategy for a three-phase inverter based on impedance-source network in grid connected applications as well as an indirect control method of the dc-link voltage. The strategy is based on a d-q synchronous reference frame and it is mainly intended for photovoltaic applications at high switching frequency. Both control systems are explained in detail and the problems and influences between them are also described. The strategy and the indirect control method of the dc-link voltage are validated and discussed by PSCAD/EMTDC simulations with a three-phase three-level neutral-point-clamped quasi-impedance-source inverter.