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Fuzzy Double Model Control for Air Supply
on a PEM Fuel Cell System
Xiaohong Hao, Haochen Zhang, Aimin An, Xin Liu, and Liwen Chen
College of Electric and Information Engineering, Lanzhou University
of Technology, Lanzhou, Gansu, China, 730050
haoxh@lut.cn, { zhanghaochen1987,anaiminll,meteor7136 } @163.com,
825781363@qq.com
Abstract. Oxygen excess ratio control is closely related to the perfor-
mance and safety of a Proton Exchange Membrane fuel cell system. Some
control strategies should be used to regulate the oxygen excess ratio at
the suitable value in order to avoid stack starvation and damage. And
in this paper, a simple fuzzy double model control has been proposed to
adjust the oxygen excess ratio under variation load currents. The double
model controller combines a PID controller and a fuzzy logic controller
which can be switched based on the fuzzy inference rules during the regu-
lation process. The simulation results demonstrate that the fuzzy double
model control can adjust the oxygen excess ratio at the setting point
when the current is changed, and improve the dynamic performance of
oxygen excess ratio than fuzzy PID control.
Keywords: PEM fuel cell, oxygen excess ratio, fuzzy control, PID con-
trol, soft switching.
1 Introduction
With the serious environmental pollution and energy crisis around the world, it
is very important for people to explore more ecient and clean energy. Proton
Exchange Membrane (PEM) fuel cell is a kind of clean energy. PEM fuel cell has
many advantages, such as high power density, clean, low operation temperature,
and which is especially used in portable power supply [1], vehicles and distributed
power plants [2]. The fuel and oxidant, usually hydrogen and oxygen or air, are
supplied continuously to the anode and cathode by the gas supplied system.
On the anode side, hydrogen is fed to track a desired ratio of the air flow by a
fast operation valve. And on the cathode side, the sucient oxygen is needed to
be supplied to the cathode channel by compressor or blower for fulfilling stoichio-
metric requirements to generate the demanded current. The insucient oxygen
supply results in the oxygen starvation phenomenon which implies a fast stack
degradation and low power generation [3]. The oxygen starvation phenomenon
occurs when the oxygen partial pressure falls below a critical level at the cathode.
And the factor oxygen excess ratio has been introduced to describe the oxygen
mass between the inlet and consumption. When the oxygen excess ration falls
 
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