Investigation of Topologies and Control Strategies of Fuel Cell Vehicles

Abstract

This paper mainly provide the discussion of the topologies applied in the fuel cell vehicles and related control strategy. The fuel cell vehicles acquires power from the fuel cell stack or from multi power sources like fuel cell stack and battery, so there are quite a few topologies can be applied in the fuel cell vehicle. According to the different topologies, there are many control strategies can be made use of to make sure the fuel cell vehicle can operate in a smooth and high efficiency state. Introduction Currently, the starving of the fossil energy and the deterioration of the environment have been widely focused. Meanwhile, more and more green gas has caused the increasing of the temperature of the earth. To solve the problem, many researchers have been involved. In the auto industry, the novel energy vehicle has been treated as an ideal solution to solve the problems. Among the novel energy vehicles, the fuel cell vehicles are deeply researched for its zero emission, high efficiency, and reasonable performance. Due to the characteristic of the fuel cell stack itself, the fuel cell vehicle with single fuel cell stack cannot fully meet the requirement of vehicle driving. Hence, researchers propose the hybrid power topologies, such as the fuel cell stack together with battery, fuel cell stack together with ultra-capacitor, .etc. The existence of the other power sources except the fuel cell stack can offset the drawbacks of fuel cell stack, such as the poor quick response performance, poor cold start performance, and fuel’s effect of hunger. Just like renewable energy vehicles, there are amount of control strategies can be applied in the fuel cell vehicles. Chang-jun Xie applies the neural network theory in the control of fuel cell vehicles [1]. Xiangjun Li employs the fuzzy logic theory in the control of fuel cell vehicles [2]. Omar Hegazy make use of the particle swarm theory to perform energy management in fuel cell vehicle [3]. By applying the advanced control theory, the fuel cell vehicle can operate in a desired state. In the following parts, the topologies of fuel cell vehicles and the control strategy of fuel cell vehicles are elaborative discussed. Topologies of Fuel Cell Vehicle According to the types of the power sources in the fuel cell vehicle, the topologies of fuel cell vehicle can be divided into two types, the single power source topology, and the multi power sources topologies. Single power source topology The fuel cell vehicle that with single power topology is driven by the fuel cell stack only. The illustration of this topology can be seen in figure 1; Motor Inverter DC/DC Fuel Cell Fig.1: Single power source topology In this topology, the fuel cell stack performs as single power source, making the structure quite simple. It also reduce the difficulty of the space layout and just requires simple energy management International Conference on Advances in Mechanical Engineering and Industrial Informatics (AMEII 2015) © 2015. The authors Published by Atlantis Press 1651 or control strategy. However, this topology has some drawbacks that make it less likely be used in fuel cell vehicles. This topology requires high power fuel cell stack, which means the cost of the fuel cell stack should be quite high. The output power of the fuel cell stack follows the requirement of the vehicle driving. When the vehicle operating in low load mode, the efficiency of the fuel cell stack could be quite low, which is not benefit for the energy-saving effect. Moreover, the fuel cell stack cannot instantly follow the requirement of vehicle driving, the acceleration of the vehicle cannot be perfect. The multi power sources topology Depends on the type and the amount of the other power source except the fuel cell stack, the multi power sources topology can be divided into following types The full power topology. The full power topology is made up of the fuel cell stack and another type of power source that commonly is battery or ultra-capacitor. The illustration of this topology can be seen in figure 2 and figure 3. Motor Inverter DC/DC Fuel Cell