Implementation of adaptive pole assignment PID controller on Dc-Dc converters for renewable energy sources

Abstract

This thesis presents the implementation of adaptive pole assignment PID controller on DC-DC converters for renewable energy sources. This study involves the modeling and development of proposed converters; buck and boost converter that controlled by an adaptive pole assignment PID controller. This study also involves the data collection of solar irradiance, temperature, and wind speed . Both converters are used to convert unregulated DC input to a controlled DC output to a desired voltage level. The system of 24V/12V is applied to a buck converter while 12V/24V is compatible to boost converter. In DC-DC converters, the output voltage on itself is usually unstable. The necessity of a control system for the converter is to maintain a constant output voltage regardless of variations in DC source voltage and the load current in closed-loop system. In regulating the output from a solar panel and wind turbine which is in direct current (DC) form, a constant output voltage is needed to supply to electronics/electronic appliances. Thus, a sophisticated conversion technique for DCDC form is required which is known as a converter. Besides, the requirement of a control system for a stable system should be with faster settling time and less overshoot voltage. However, the output voltage of the converters on itself is usually unstable and oscillates especially at the beginning of the transient response. The existing of the damping elements; resistor and inductor in the circuit of the converters contribute to the high percentage of overshoot voltage and output voltage ripple. Practically, the high overshoot voltage may lead to spark current which it could harm to consumers. Therefore a converter with a controller is needed to overcome the problem. The data collection of solar irradiance, temperature, and wind speed were analysed to know the potential of solar and wind energy application in Perlis. These data were measured using weather station that already installed at the Centre of Excellent for Renewable Energy (CERE), located in Kangar, Perlis. Based on the average monthly solar irradiance for the year 2011, the average reading of solar irradiance is 1229W/m2 while the highest speed of wind is recorded at 26.56m/s. This show that both energies have a potential PV and wind power generation in Perlis. Meanwhile, the performance of DCDC converters and the proposed controller have been evaluated in terms of percentage of overshoot in the output voltage as well as inductance current using Matlab/Simulink software by analysing the effect of damping element; load resistor. Then, the results obtained will be evaluated with experimental results. These converters are then have been implemented into real-time with application of PIC microcontroller. Based on the simulation results, the performance of converters that simulated with the calculated value of the load resistor; 40Ω, show a better result compared to trial and error value, 84Ω whenever simulated with the proposed controller. Besides, the experimental results show that the proposed controller is capable in minimizing the occurrence of overshoot in output voltage and inductance current besides provide a better performance by reducing the oscillation in steady state and faster settling time. Overall, the simulation results and experimental results are evaluated and prove a satisfactory of the proposed controller to adapt with DC-DC converters as well as in these energy system.