H∞ controller for power sources applied to electrical vehicles

This paper treats a control strategy for obtaining an energy management system for average power electrical vehicles. A very important system from an electrical vehicle is represented by the power supply system which can be composed of at least two are more sources like fuel cell, battery and ultra-capacitor as example and an energy management system is needed in order to satisfy power demand of the electrical motor on vehicle. The main purpose of this paper is to use an H
_∞
optimization strategy for controlling the high frequency variations of power demands in condition, the fuel cell will ensure the average power and the system formed by battery and ultra-capacitor, the rest of the energy. One of the reason for using such pair of energy sources, battery and ultra-capacitor is not only to energize the electrical motor and other power consumptions peripherals, also to reuse the kinetic energy produce by braking or stopping at the traffic light. In this work a power flow coordination it is presented between three sources connected in parallel, each one having a DC-DC converter and the fuel cell it is unidirectional comparing with the other sources. Each element from this power system is considered as current source controlled according to a reference. This method H infinity norm, represents a mathematical optimization problem to obtain a source with high energy density for long period and a source with high power density able to provide high power for a short period of time.