A DC-DC buck converter with maximum power point tracking implementation for photovoltaic module application

摘要

Use of DC-DC converter in continuous operation mode can enhance the energy extraction from solar panels. This paper presents a DC-DC buck converter model with reduced size and yet yielding high efficiency. A DC-DC converter which generates a constant DC voltage was selected to observe the photovoltaic operation at maximum power point (MPP). The filtering parameters of the converter were computed and selected with a metal-oxide-semiconductor field-effect transistor (MOSFET) switching at a frequency of 25 kHz. However, the I-V (current-voltage) characteristic is affected by irradiation and temperature, which have a nonlinear relationship. This requires the duty cycle to be calculated and changed to turn the converter to the maximum power available. The change in irradiation and temperature give a different MPP at different curves. Thus, voltage and current sensors and a microcontroller are required to calculate the optimum duty ratio to operate always at MPP. In order to generate a pulse width modulation (PWM) to control converter switch (the MOSFET), the microcontroller is controlled by an algorithm that has been written in C programming language. The algorithm of the MPP tracker (MPPT) operation is achieved by using the perturbation and observation (P&O) method to provide high tracking accuracy and fast response. Furthermore, the system has been designed using MATLAB and PLECS platforms. The simulation results are validated by developing a prototype. The empirical results validated the simulations.