Microtracking Algorithm for Concentrating Photovoltaic Application

open_access
Open Access
Author:
Ren, Andrew James
Area of Honors:
Electrical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
Noel Christopher Giebink, Thesis Supervisor
Professor William Evan Higgins, Thesis Honors Advisor
Keywords:
concentrating photovoltaics
control systems
Abstract:
Concentrating photovoltaic (CPV) power is promising due to demonstrated high efficiency in comparison to traditional Silicon solar panels. Because of the movement of the sun during the day, the sheet containing solar cells needs to adjust to stay under focused sunlight. The microtracking approach used took advantage of concentrating optics that kept focused sunlight in a plane. The movement system was implemented with Shape Memory Alloy (SMA) actuator wires and was controlled with a Proportional Integral Derivative (PID) Controller. The PID Controller toggled a Pulse Width Modulated (PWM) signal to contract and relax the SMA Wire. Gain constants in the PID controller were tuned to optimize step responses on the wire lengths. The implementation allowed for three independent PID controllers to be run on the same system to move the center sheet to specified locations. With proper insulation, the usage of actuator wires has potential to consume less power than commercial stepper motors, which would decrease the power consumption of the CPV system as a whole. When coupled with an error cell feedback approach to keep the solar cells under focused sunlight, this system is both inexpensive and accurate to maximize power generated by the cells.