Abstract: Various examples are provided for operational control of fuel cells. In one example, among others, a system for controlling a fuel cell includes a stack temperature controller in cascade with a liquid level controller. The liquid level controller can provide a control output based at least in part upon an indication of a liquid level of a liquid fuel tank and a level reference. The stack temperature controller can provide a fan speed control output based at least in part upon an indication of a stack temperature of the fuel cell and the control output of the liquid level controller. In another example, a system for estimating methanol concentration of a fuel cell system includes a state observer that generates an estimate of the methanol concentration of fuel provided to a direct methanol fuel cell based upon a plurality of states of the fuel cell system.

Abstract: Various examples are provided for operational control of fuel cells. In one example, among others, a system for controlling a fuel cell includes a stack temperature controller in cascade with a liquid level controller. The liquid level controller can provide a control output based at least in part upon an indication of a liquid level of a liquid fuel tank and a level reference. The stack temperature controller can provide a fan speed control output based at least in part upon an indication of a stack temperature of the fuel cell and the control output of the liquid level controller. In another example, a system for estimating methanol concentration of a fuel cell system includes a state observer that generates an estimate of the methanol concentration of fuel provided to a direct methanol fuel cell based upon a plurality of states of the fuel cell system.

Abstract: Techniques, systems and methods for designing, implementing, and operating model predictive controllers that can deliver perfect tracking of set points and that can reject the effect of disturbances when steady-state operation is reached are disclosed. High performance is achieved through the incorporation of set-point tracking costs, integral costs, and velocity costs, as well as the adoption of incremental model systems for prediction purposes. Embodiments can deliver offset-free performance for tracking set points with constant final values, set points of a ramp type, and set points of a parabolic form, while rejecting disturbances that have a constant final value. The approach reduces the complexity of model predictive control design, delivers improved performance, and requires modest computational power.

Abstract: Techniques, systems and methods for designing, implementing, and operating model predictive controllers that can deliver perfect tracking of set points and that can reject the effect of disturbances when steady-state operation is reached are disclosed. High performance is achieved through the incorporation of set-point tracking costs, integral costs, and velocity costs, as well as the adoption of incremental model systems for prediction purposes. Embodiments can deliver offset-free performance for tracking set points with constant final values, set points of a ramp type, and set points of a parabolic form, while rejecting disturbances that have a constant final value. The approach reduces the complexity of model predictive control design, delivers improved performance, and requires modest computational power.