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

摘要

A design of an inexpensive and efficient maximum power point tracker 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-down chopper, 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 the look-up table stored in the computer for (V/sub m/) versus the measured (V/sub oc/). This table is obtained from theoretical calculations for maximum power points locus of the solar cell array (SCA) used. For the difference between the theoretical and experimental locus of the maximum power points, for temperature effect, degradation of the (SCA) and dust effect, the oscillation about the theoretical point is used to determine the actual point. It is also used for the (power-voltage) curve of the SCA.