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This paper proposes a new control algorithm that improves the dynamic performance in distributed maximum power point tracking systems. Systems with these architectures allow to increase the photovoltaic power harvested in case of partial shading and irradiance mismatch. The classical approach adopts distributed DC/DC power electronics and control without any centralized action, which makes difficult to know whether the system is working on its optimal operating point or not. The new control algorithm presented in this paper exploits the benefits of the vectorial multi-variable perturb & observe logic and acts on the control sequence under varying irradiance conditions, reducing voltage stresses at the DC/DC converters output terminals. In addition, the matching with the DC-bus voltage control is discussed, providing a centralized control to the overall system, a fact barely addressed in literature. Simulation results and experimental measurements validate the proposed approach showing improved dynamic performance and system stability.

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This paper presents the analysis, control and implementation of the interleaved three-port boost converter. The scope of this paper is the interfacing of photovoltaic systems that include storage. A new symmetrical PWM modulation strategy that prevents unwanted switching states without requiring external circuitry is presented. This modulation allows for proper sampling of the measurements, increasing thus their accuracy. Large- and small-signal models of the interleaved and non-interleaved three port boost converters are presented and transfer functions are derived for control design purposes. The different currents in the converter are controlled using control loops that govern the behavior of the converter. These loops are intuitively designed by treating them independently. With the proper loop bandwidth selection, the converter achieves fast response and good reference tracking and is suitable to interface photovoltaic and storage systems with different kinds of loads. The presented models, modulation and control loops are validated through simulation and with experimental results.

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