Sliding Mode Control for PEM Fuel Cells

A fuel cell is an energy converter which converts the chemical energy to the direct current electricity through an electrochemical reaction. Polymer electrolyte membrane (PEM) fuel cell is one of the types of fuel cells which has various industrial and military applications. In order to obtain the desired performance in PEM fuel cells, it is required to design a control scheme achieving the control objectives such as air and hydrogen management. In order to obtain the desired performance in PEM fuel cells, it is required to design a control scheme achieving the control objectives such as air and hydrogen management. Therefore, we design robust control schemes based on the sliding mode method. The state-feedback control law is not a continuous function of time. Instead, it can switch from one continuous structure to another based on the current position in the state space. Hence, sliding mode control is a variable structure control method. The motion of the system as it slides along these boundaries is called a sliding mode and the geometrical locus consisting of the boundaries is called the sliding (hyper)surface. In the context of modern control theory, any variable structure system, like a system under SMC, may be viewed as a special case of a hybrid dynamical system as the system both flows through a continuous state space but also moves through different discrete control modes.A fuel cell is an energy converter which converts the chemical energy to the direct current electricity through an electrochemical reaction. Polymer electrolyte membrane (PEM) fuel cell is one of the types of fuel cells which has various industrial and military applications. In order to obtain the desired performance in PEM fuel cells, it is required to design a control scheme achieving the control objectives such as air and hydrogen management. Thus, in this paper, we design robust control schemes based on the sliding mode method. . The state-feedback control law is not a continuous function of time. Instead, it can switch from one continuous structure to another based on the current position in the state space. Hence, sliding mode control is a variable structure control method. The motion of the system as it slides along these boundaries is called a sliding mode and the geometrical locus consisting of the boundaries is called the sliding (hyper)surface. In the context of modern control theory, any variable structure system, like a system under SMC, may be viewed as a special case of a hybrid dynamical system as the system both flows through a continuous state space but also moves through different discrete control modes The proposed control schemes achieve the optimal output power via regulating the oxygen excess ratio in the air supply subsystem and also regulate the hydrogen pressure in the PEM fuel cell.We consider the nonlinear dynamical model of a PEM fuel cell including air supply subsystem, dynamics of oxygen, nitrogen and vapor in cathode and dynamics of hydrogen and vapor in anode. Figure ۱ shows this fuel cell system. In order that the fuel cell works at its optimal operation point and for avoiding oxygen starvation, the oxygen excess ratio (the ratio of oxygen mass flow to reacted oxygen mass flow in cathode) should be maintained at its desired value. Also, in order to avoid hydrogen starvation, the hydrogen pressure should be maintained at its desired value. Thus, for the considered nonlinear dynamical model of PEM fuel cell, we design a control scheme based the sliding mode method achieving the objectives of oxygen excess ratio and hydrogen pressure regulation.A nonlinear dynamical model for PEM fuel cell has been considered. Then, a control scheme achieving the control objectives such as air and hydrogen management has been proposed