Mechanical Sun-Tracking Technique Implemented for Maximum Power Point Tracking of a PV System for Effective Energy Supply

  • DBN Nnadi
  • SE Oti
  • DC Ahiabuike
Keywords: Solar panel, maximum power point tracker, Sun tracker, tracking sensors, priority voltage, Mechanical maximum power point tracker.

Abstract

This paper elucidates a single axis solar tracker system that automatically searches the optimum PV panel position with respect to the sun by means of a DC motor controlled by an intelligent drive unit that receives input signals from light dependent sensors. A prototype of the mechanical maximum power point tracker (MMPPT) was implemented with a motor size of 48W. The power supply unit consists of only supply source which is the AC mains. The sensor unit consists of six sensors. While five are fixed and adjacently aligned at 36o to each other (tracking sensors), the sixth one is movable as it is attached to the surface of the PV panel (feedback sensor). The control unit is divided into two parts: A priority voltage selector and a movement controller. The priority voltage selector comprises of cascaded comparators which compares the five voltage outputs from the sensors and selects the highest voltage (priority voltage).The movement controller compares the feedback voltage with the priority voltage and logically decides whether to move the motor clockwise or anti-clockwise. The solar panel is allowed to move from east to west and back forth with a maximum allowable angle of 180o. Its movement is in only one axis. The prototype built carries the panel from eastward to westward tracking the sun movement from sun rise to sun set and then reset to face eastward as darkness sets in. The results obtained from the prototype MMPPT were used to compare with the results obtained from fixed panel under the same environmental conditions and at the same time interval of 30 minutes using the same type of PV panel. The result from MMPPT has a gain of 5.77% over its counterpart which is fixed panel.

http://dx.doi.org/10.4314/njt.v33i2.13

Published
2014-04-14
Section
Research papers

Journal Identifiers


eISSN: 2467-8821
print ISSN: 0331-8443