基于滑模变结构的燃料电池离心空压机流量控制

摘要

质子交换膜燃料电池是利用氢气与氧气的电化学反应产生电能的装置,其中空气压缩机是关键部件,负责向燃料电池的阴极供给空气(含约21%氧气),与氢质子、电子产生电化学反应.供给空气的流量与压力之间影响到燃料电池的输出性能,即V-I特性曲线,同时对燃料电池系统的安全性产生影响.不足的空气供给会使燃料电池产生"氧气饥饿"现象,会降低燃料电池的寿命,严重情况下会破坏质子交换膜.采用滑模变结构方法控制离心压缩机的输出流量,使其在动态负载情况下满足燃料电池对空气供给的要求,采用基于super-twisting的二阶滑模控制压缩机的驱动转矩,实现对输出流量的动态调节,仿真结果证明了该方法的有效性.%Air compressor is the key component in the proton exchange membrane fuel cell (PEMFC) system which utilizes the electrochemical reaction of the hydrogen and oxygen to produce electricity.Compressed air (including 21 % oxygen) provided by the compressor has to be supplied to the cathode of PEMFC.The mass flow and pressure of the supplied air directly influence the output performance, i.e., the V-I characteristics, as well as the safety of the fuel cell.Insufficient air flow may lead to the "oxygen starvation" phenomenon which reduces the fuel cell lifespan and could damage the membrane in the sever case.In order to satisfy the fuel cell requirement, a sliding model controller is developed in this paper to control the mass flow.A super-twisting method is used to control the compressor driving torque and thereby the mass flow dynamics.The proposed method is validated by the simulation results.