Event-triggered Dual-mode Control of Maximum Power Point Tracking for Photovoltaic Arrays

Photovoltaic power generation systems will switch between two situations: uniform illumination and local shadow. For maximum power point tracking (MPPT), the conventional strategy is often efficient in only one situation. But for both situations with switching, there face problems such that the tracking time may be too long or it may fall into the local maximum power point (LMPP). Aiming at these problems, in this paper, an event-triggered dual-mode control technology is proposed, which enables the system to work with high efficiency and high precision under both uniform illumination and local shadow. Under the uniform illumination, the maximum power point is tracked by the perturbation method (P&O), while in a local shaded environment, the current flowing through the bypass diode acts as a trigger signal which enables Particle Swarm Optimization (PSO) to track the Global Maximum Power Point (GMPP). The simulation experiment by Matlab shows that in both the uniform illumination and local shadow, the algorithm of event-triggered dual-mode control is efficient in MPPT and has a fast and smooth transition between P&O and PSO, overcoming the problems of conventional strategy.