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.