Multi-level converter
A multi-level converter (MLC) is a method of generating high-voltage wave-forms from lower-voltage components. MLC origins go back over a hundred years, when in the 1880s, the advantages of DC long-distance transmission became evident.
Modular multi-level converters (MMC) were investigated by Tricoli et al in 2017. Although their viability for electric vehicles (EV) was established, suitable low-cost semiconductors to make this topology competitive are not currently available (as of 2019).
In 1999, Tolbert described the use of MLC for battery operated electric motors.
Habib's 2018 review paper reviews multi-level inverters (a synonym for MLC) stating the advantages of bi-directional energy flows to power the motor or charge the battery system.