Dual Axis Solar Tracker Method using Internal Model Control based Proportional Integral Derivative Controller
Dual axis solar tracker is an electromagnetic device used for tracking the sun’s apparent position in both horizontal
and vertical axis. However, it suffers from external disturbances like wind, sun intensity and direction which limit its stability.
Conventional Proportional Integral Derivative (PID) controller previously used in turning methods such as Ziegler-Nichols
(ZN), Chien-Hones-Reswick (CHR) and Tyreus-Luyben(TL) was characterized with inadequate poor tuning of its control
parameters. In this work, the dual axis solar tracker method using internal model control based proportional integral derivative
controller was carried out. The dual-axis solar tracker comprises DC motor coupled with solar panel was developed using
Permanent Magnet Direct Current (PMDC) motor equation. Internal Model Control-based PID controller (IMC-PID) was
used to control the developed model. The developed IMC-PID-based system was simulated in Matrix Laboratory
2013aversion. The performance of the simulated IMC-PID-based solar tracker was evaluated in Reference Tracking Mode
(RTM), Input Disturbance Rejection Mode (IDRM), Output Disturbance Rejection Mode (ODRM) and Controller Effort
Mode (CEM) using rise time, settling time and overshoot as performance metrics. The performance of the IMC-PID based
system was compared with Chien-Hones-Reswick (CHR-PID), Ziegler-Nichols (ZN-PID) and Tyreus-Luyben (TL-PID)
tuning methods. The simulation results of IMC-PID based dual axis solar tracker gave the rise time of 1.2s, 0.5s, 1.8s and 1.8s
for CEM, IDRM, ODRM and RTM respectively. The settling time of 4.7s, 7.2s, 1.7s and 5.5s for CEM, IDRM, ODRM and
RTM respectively were obtained. While the poorest settling times obtained were 26.9s, 12.4s, 10.1s and 10.1s for ZN-PID at
CEM, CHR-PID at IDRM, TL-PID at ODRM and TL-PID at RTM. Also, poorest rise time results obtained were 15.9s, 10.3s,
9.3s and 7.0s for ZN-PID at ODRM, TL-PID at CEM, TL-PID at RTM and ZN-PID at IDRM. The overshoot simulation results
reflected that IMC tuning method gave the best overshoot of 1% at IDRM and ODRM respectively, while other tuning
methods gave higher results at different modes. The developed IMC-PID based dual axis solar tracker gave the best
performance in terms of rise time, settling time and percentage overshoot over ZN-PID and TL-PID tuning Methods therefore,
the developed IMC-PID based dual axis solar tracker in solar powered Electricity generating companies can be used to
improve the quantity of energy harnessed from the sun.
Keywords - Axis, Controller, Tracker, Solar.