Microcomputer controlled buck regulator for maximum power point tracker for DC mumping system operates from photovoltaic system

摘要

A design of an inexpensive and efficient maximum power point tracker (MPPT) is presented. This design calls for a pilot module to track the maximum power point voltage (V{sub}m). The tracking is done by changing the duty cycle of a step-downchopper, which is controlled by a software P voltage controller. The controlled voltage of the tracker (V{sub}m) is obtained by measuring the open circuit voltage (V{sub}(oc)) and searching in Look-Up table stored in the computer for (V{sub}m) versus themeasured (V{sub}(oc)). This table is obtained from theoretical calculations for maximum power points locus of the used solar cell array (SCA). For the difference between the theoretical and experimental locus of the m mum power points, for temperatureeffect, degradation of the (SCA) and dust effect, oscillation about the theoretical point is made to determine the actual point. The oscillation is made for the (power-voltage) curve of the used SCA.