Variable voltage variable frequency options for series hybrid vehicles

This paper explores concepts for advanced series hybrid vehicle propulsion systems. These concepts are variations on the variable voltage variable frequency (VVVF) concept, where the electrical bus frequency and voltage vary proportionally with the system operating point. The concepts involve doubly fed machines. Each of these concepts has the potential to provide a full series hybrid drive with substantially reduced needs for electronic power conversion. The paper discusses the basic structures and performance of these machines, and provides a tabulation of the machine and power converter requirements over a typical operating range. Finally, conclusions are offered regarding the relative merits of these schemes.