PID control of non-square systems and its application in the fuel cell voltage

This paper studies PID control for non-square systems. A non-square system has unequal numbers of inputs and outputs and there exists coupling among its PID controllers. The coupling can´t be simply eliminated using conventional decoupling methods for square systems, thus it is hard to tune PID controllers for non-square systems. In this paper, we adopt predictive control for non-square systems since predictive control method doesn´t assume that the dimensions of inputs and outputs are equal and it is suitable for the control of non-square systems. To implement the final controller in practice, the paper proposes to reduce model predictive control(MPC) into PID control. The method is applied to a voltage model of Proton Exchange Membrane Fuel Cell (PEMFC). Simulation results show that the method can achieve better load rejection ability and robustness compared with traditional methods.