This paper deals with a current topic addressing the issue of energy management. Adequate energy management consists of finding the best harmony between different sources intended to supply the vehicle to satisfy the power required by the traction motor while ensuring good performances. Energy management strategy makes it possible to find the adequate distribution of the energy flow between power source elements by generating power references to be given by each source to satisfy the required power while respecting the constraints on these sources. In this context, a new energy management strategy based on the combination of flatness theory and the frequency separation principle is developed. This strategy determines the powers that the energy sources must supply and provides power source references based on their dynamics, imposing constraints to be taken into account. This novel hybrid strategy is applied to a hybrid vehicle configuration that uses a fuel cell as the primary source with a hybrid storage device (supercapacitor and battery). The implementation using dSPACE DS1005 will be presented to demonstrate the effectiveness of the proposed strategy.