Hybrid 17-level inverters based on T-type flying-capacitor and switched-capacitor

The purpose of this work is to use fewer components to generate more output levels for power interfaces of low dc voltage sources such as fuel cells. First, two switched-capacitor voltage lifters (SCVLs) with similar structure and same function are summarized. Each of them uses a single capacitor and has the advantage of identical voltage stress for all components. Then, the SCVLs are combined with a T-type unit to develop two 17-level inverters. The SCVLs is responsible for voltage boosting, while the T-type unit uses two flying capacitors to increase the number of output levels. In addition to the use of three capacitors, the two 17-level inverters employ 13 and 14 semiconductor switches respectively, and all components' voltage stresses do not exceed the dc input voltage. Simple structure, reduced capacitors' count, and low components' voltage stress are the main merits of the proposed inverters compared with other 17-level inverters. Beyond theoretical analysis, both steady-state and dynamic performances are verified experimentally, and the highest efficiency measured by the experiment is up to 97.8%.