Comparison of the performance of MPPT methods applied in converters Buck and Buck-Boost for autonomous photovoltaic systems

Abstract

In photovoltaic (PV) generation systems, the energy produced is limited by the low efficiency of the solar panels, the variability of weather conditions, and the characteristics of the load connected, so the use of maximum power point tracking (MPPT) methods is essential to maximize the power supplied. Implementing an MPPT requires a power converter as the interface between the PV array and the load, so the converter's behavior is also an important factor to be considered in the overall performance of a PV system. Several MPPT techniques have been proposed over the years, but little literature is still available when required to be compared to the combined performance of different MPPT/converter sets. In this context, the present work presents a comparative study of the performance of three MPPT techniques: constant voltage (CV), perturb and observe (P&O), and incremental conductance (IncCond), acting on two different topologies of DC-DC power converters: Buck and Buck-Boost. Each combination is analyzed considering its transient response and steady-state average efficiency. The study was carried out based on simulations in Matlab/Simulink environment. To obtain more realistic conditions, a model for the commercial PV module Kyocera KC85TS was developed. Results obtained from the PV system operating under various radiation and temperature conditions are compared and discussed, which show that the CV/Buck-Boost combination showed the best transient behavior and that the IncCond/Buck combination had the highest steady-state efficiency.

Design and Implement of Step-Up DC-DC Converter with a Professional Approach using MATLAB/Simulink

“…An equation describing the ripple voltage is as follows: (24) or (25) When considering the switching frequency, denoted as an alternative approach involves expressing capacitance in relation to the output voltage ripple, resulting in:…”

“…The adoption of continuous current mode operation in this study is aimed at achieving enhanced regulation within the circuit. Predominantly utilized converters in power electronics encompass buck [13][14][15][16], boost [17][18][19][20] and buckboost [21][22][23][24] converters. Nonetheless, in PV-based applications, the boost converter is the more prevalent choice, and this research proposal centers on a boost converter due to its superior stability and efficiency.…”

A maximum power point tracking of a photovoltaic system connected to a three-phase grid using a variable step size perturb and observe algorithm

“…The P&O method compares the power of the previous step with the new step's power to increase or decrease the tension in search of the MPP. According to [6][7][8][9][10][13][14][15][16][17][18][19][20][21][22][23][24][25][26], the MPP value is never definitively reached since the disturbances only leave the system oscillating close to the MPP in a steady state. The P&O method presents good results when the irradiance or temperature does not change rapidly with time.…”

“…DC-DC converters have wide applications in PV systems. Whether it is a boost converter [15][16][17][18][19], buck-boost converter [20,21], or buck converter [13]. DC-DC converters are considered the main element in the MPPT process; without them, the maximum power could not be achieved.…”