Double Inverter as a Multilevel Converter: Circuit Topology, Modulation Strategies and Applications

A way to achieve multilevel converter structure using two standard three-phase two-level inverters is presented in this paper. In order to obtain the typical multilevel voltage waveforms it is necessary to synchronize the commutations of the two inverters by a proper modulation strategy. Here, two modulation strategies areresented: the first one allows only generating the characteristic multilevel line-to-line voltages; the second one allows controlling the power flows from the two inverters too. Eventually, it is discussed some suitable applications or the system described in automotive and naval fields