Design of Multicell Converters

Power electronics is the discipline that allows converting electrical energy from one form to the other (DC=>AC, low voltage=>high voltage, unregulated=>regulated,...) with an efficiency that can theroretically reach 100%. This is achieved with semiconductors operating in switchmode (~0V when ON, ~0A when OFF => 0 losses) and passive components (~0 active power=> 0 losses) to smooth the power flow. There are many ways to connect these elements and each of these topologies will in practice give a different performance (weight, efficiency,...). In recent years we have introduced several new variants of multicell topologies that need to be compared to more standard topologies, which led us to develop specific design methods that are exemplified here. In many cases it is possible to describe a n-cell converter with 'n' as a simple parameter, the case n=1 giving the standard two-level topology; whenever possible, this is used to allow easy comparison of standard and multicell topologies and this applies to both simulation (circuit=> waveforms) and design (specifications=>circuit).

We give here a few examples of tools that illustrate various aspects of this know-how :