An adaptive, linear-line approximation method and its VLSI implementation for maximum power control of photovoltaic system

Photovoltaic (PV) systems are renewable sources whose operating voltage and current are nonlinearly dependent on the temperature and sunlight intensity. Therefore, maximum power point (MPP) tracking is important for extracting as much power as possible from PV arrays. The Linear-line Approximation Method (LLAM) is able to converge to the MPP quickly regardless of the changes of sunlight intensity. However, the slope of the linear line method becomes non-optimal as the temperature changes, causing the PV systems to leave its MPP. This paper proposes a modified LLAM whose line slope can adapt automatically in response to temperature changes, maintaining an optimal MPP control. After verifying the feasibility and capability of the proposed algorithm by simulation, the proposed algorithm is further implemented as a microsystem in VLSI (Very Large Scale Integration). The application-specific VLSI is expected to achieve higher control efficiency and lower power consumption.