Single input qZ‐source cascaded multilevel inverters: Analysis, design, and implementation

The Single Input quasi‐Z‐Source Cascade Multilevel Inverter (SIqZS‐CMI) has the ability to make use of a single DC input source and to share active power among all cascaded qZS modules. This unique feature, do not present in any other quasi‐Z‐Source (qZS) multilevel inverter in the literature, is accomplished by replacing one of its Z‐impedance inductances by a coupled inductor. With this topology, it is possible to make use of a single low voltage PV string, favoring the use of small size residential rooftop systems. In addition, it simplifies the system grounding and the compliance with many Installation, Maintenance, and Safety Codes and Standards. The proposed control strategy enables high quality current injection into the grid, keeping the DC bus voltage regulation, ensuring precise power balancing with symmetric multilevel waveforms. Experimental results from a 5‐level SIqZS‐CMI prototype demonstrate the system's performance and its advantages. Proposed grid‐tied 2k+1 levels SIqZS‐CMI topology