This electric energy conversion system of the type including a main converter (40) connected at the input to at least one input network (41) operating under an input voltage and at the output to an output network (42) operating under an output voltage and associated with an electric energy storage device, operating under a storage voltage, including a bidirectional charger (46) connected to the output network (42) on the one hand and to capacitive electric energy storage means (48) on the other hand, the operation of the bidirectional charger (46) being driven by control means (49) for slaving the output voltage on a first set value (Vref2), is characterized in that the operation of the main converter (40) is driven by control means (50) for slaving the storage voltage on a second set value (Vref1).