PWM-control of multi-level voltage-source inverters
Supercapacitors represent one of the newest innovations in the field of electrical energy storage, and will find their place in many applications where energy storage is needed, or can help to the smoothing of strong and short time power solicitations of a distribution network. Other system developments are going on, opening new fields in engineering sciences, based on new possibilities in the field of electrical energy storage. In comparison with classical capacitors, these new components allow a much more higher energy density, together with a high power density. Even if the energy density is not comparable with that one of electrochemical accumulators, the possible energy amount and storage time is compatible with many industrial requirements. In transportation systems, as a first example, the energy needed to relay two bus-stations can easily be transferred from a fixed supercapacitor storage device to another mobile one placed on a bus during passenger transfer time, allowing so the use of electrical propulsion without trolleys . Other complementary storage systems for better share of energy and instantaneous power amounts have also been described , as well as supercapacitor tanks as booster for fuelcell powered passenger cars . This contribution will show some actual research and development projects, running at university level, but in connection with specialists from the corresponding application fields. Innovative and promising solutions and technologies are investigated, which need of course clarification of their actual industrial and economical compatibility. They can also be seen as future solutions for next decades, in relation with the tendency of getting weaker distribution of electrical energy.