الخلاصة:
Concerns over the environmental impact of fossil fuels in recent years have engendered a search for
alternative, environmentally-friendly, renewable, energy sources. Amongst the several possible
sources of renewable energy systems that have been exploited in recent years, wind and solar
energy systems offer the most significant possibility for large-scale integration. The high initial cost
of acquisition of wind /solar energy systems require further cost-mitigation strategies to support
both the affordability, and the economics of exploiting these two renewable energy sources. Few
locations on earth are equally endowed with these two renewable energy sources in exact
proportions: hence the decision to exploit either one of them depends naturally on the incidence of
natural occurrence of the source. The atmosphere which gave rise to the research development that
resulted in the current work, was born in a geographical environment that has an abundance of solar
energy. The research activities themselves were driven both by the need to make solar tracking
systems cost-efficient, as a means of reducing the overall cost of acquiring solar energy systems;
and by the need to develop systems that would operate robustly and reliably under challenging
environmental conditions, over their quoted lifespan. Polar-axis solar tracking was identified for
cost reduction: the discourse here shall, therefore, mainly highlight contributions in respect of
polar-axis solar tracking, even though, most of the technical issues addressed in polar-axis solar
tracking also apply to solar tracking systems in general. Specifically, the discourse begins with a
general review and comparison of the relative issues around static and tracking solar systems. A
review of the various types of tracking systems and their motive or drive systems, in terms of
system modeling, dynamic performance and the economics issues, is presented. Solar tracking
systems require information on the moment-by-moment position of the sun relative to a given
platform (location), to effect tracking accuracy. Methodologies and the merits and demerits of
sensor-based and sensorless identification of the position of the sun shall be discussed. Linear and
non-linear model-based polar-axis tracking techniques shall be demonstrated. A discussion of
frictional effects, ageing and parameter variation due to the weathering and natural elements shall
be drawn-upon, to motivate the need for non-model based control of polar-axis solar tracking
systems. Non-model-based control shall then be discussed. Artificial intelligence-based controllers
shall then be advanced. Constraint-based polar-axis solar tracking shall be discussed. Limitations of
tracker economic as a means of lowering the cost of solar energy hardware shall be elucidated, to
motivate the need for the hybrid exploitation of renewable energy systems. Conclusions and further
research directions shall be discussed
