This paper introduces a novel maximum power point tracking (MPPT) technique aimed at maximizing the power produced by photovoltaic (PV) systems. The largest part of the MPPT approaches presented in the literature are based on the sensing of the PV generator voltage. On the contrary, in this paper, a current-based technique is proposed: the sensing of the current in the capacitor placed in parallel with the PV source is one of the innovative aspects of the proposal. A dual control technique based on an inner current loop plus an outer voltage loop allows to take profit of the fast current tracking capability of the inner current loop while the voltage loop benefits from the logarithmic dependency of the PV voltage on the irradiation level. The features of the proposed algorithm, particularly in terms of tracking of irradiation variations and disturbance rejection, are supported by theoretical analysis, simulations, and experimental results. The technique described in this paper is patent pending.

A novel dc-dc switching converter consisting of a boost stage cascaded with a buck converter with their coils magnetically coupled is presented. The disclosed converter has the same step-up or step-down voltage conversion properties than the single inductor noninverting buck-boost converter but exhibits nonpulsating I/O currents. The converter control-to-output transfer function is continuous between operation modes if a particular magnetic coupling is selected. The addition of a damping network improves the dynamics and results in a control-to-output transfer function that has, even in boost mode, two dominant complex poles without right-half-plane zeros. An example shows that an output voltage controller can be designed with the same well-known techniques usually applied to the second-order buck regulator. Details of a prototype and experimental results including efficiency, frequency, and time domain responses are presented. The experimental results validate the theoretical expected advantages of the converter, namely, good efficiency, wide bandwidth, and simplicity of control design.

This paper proposes a proton exchange membrane fuel cell control strategy to produce the power requested by an electrical load, minimizing the fuel consumption and also providing a regulated DC bus voltage to the load. The power system consists of a hybrid fuel cell/capacitor topology, and the control objective is to follow the minimum fuel consumption points for a given load power profile. This is done by controlling the air pump voltage and regulating the fuel cell current through a DC/DC switching converter. Moreover, the design and control parameters of the output DC bus are discussed, and the calculations are adjusted to a Ballard 1.2-kW Nexa power module. Finally, the control results, fuel consumption, and fuel cell protection against oxygen starvation phenomenon are analyzed and experimentally validated, contrasting its performance with the Nexa power module internal control system.