2. "Technology bricks

For on-board electrical power generation, dual-mode and hybrid powertrains essentially use a thermal engine (diesel or, more rarely, a turbine) combined with an electrical generator. However, still on an experimental basis, they sometimes make use of a new electrical generator: the fuel cell (PAC).

When it comes to energy storage, dual-mode and hybrid rail drives call on new "technological building blocks" that have hitherto been little used for high-power applications. These include batteries, supercapacitors and flywheels.

The development of these dual-mode or hybrid powertrains cannot be envisaged without the use of power electronic converters, in particular DC/DC choppers or DC/AC inverters, which are essential for regulating energy exchanges between the various sources and loads.

Power electronics have now become...