This research aims at developing an active energy management system for an experimental platform of the multi-energy-source electric vehicle (EV). The main purposes are to deal with the shortages of long charging time, short battery life cycles, and insufficient mileage of EVs. Hence, this research was separated into three segments: (1) active power distribution hardware, and (2) performance verification on an experimental platform. The selected green energy sources for EVs are fuel cells, supercapacitors and lithium batteries. The fuel cell were determined to be the range extension source, the batteries were the main energy provider, while the supercapacitors was the high-power-assist device. The energy management was with four modes: EV mode, hybrid mode, range-extension (RE) mode, and the supercapacitor-power assist mode. For the active power distribution hardware, a self-designed control board was integrated at the input for traction power and (or) output for charging power of each energy source. It consists of a DC/DC converter to regulate the output current (power), a variable resistance to control the commanded voltage for the regulated current, and twelve electric capacitors for the current filter as well as for the compensation of slow dynamics of IC circuit. The energy management control was coded on the Matlab/Simulink environment, and was consequently downloaded to a rapid-prototyping controller, where the inputs are the traction motor power and the outputs are the regulated current commands of three energy sources. Experimental results show that under various battery state-of-charge (SOC), and time-variant outload, the active power module provide the proper energy management online. The implementation on a real EV will be conducted in the future.