Publication: In-depth comparison between the control techniques for standalone PV systems
Loading...
Date
2024-07
Authors
Muhammad Sahlan bin Abd Rahman
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Approximately thirty percent of the world’s greenhouse gas emissions come from the production of electricity from fossil fuels such as coal and natural gas. In
order to produce cleaner electricity a standalone photovoltaic (PV) system have become one of the famous options especially to provide electricity in remote locations. In a standalone PV system, it generally consist of a DC-DC converter and an inverter to convert DC input into usable AC output. For an inverter to function properly to produce a correct AC output characteristic, a stable input voltage must be fed into the inverter. Since a PV array is used as a source in the standalone PV system, the DC voltage produced will have variations and inconsistent as it depending on the environmental conditions such as irradiance and temperature. To tackle this problem, a control technique needs to be integrated at the DC link to regulate and maintain a stable DC voltage from the PV array. In this research, 2 different DC link voltage control will be studied and compared for their effectiveness in a standalone PV system which is Proportional-Integral (PI) Control and Perturb And Observe based Voltage Regulator (POVR) control. PI control is a widely used voltage control techniques which is known for its simplicity and effectiveness. While POVR is a newly proposed control techniques that integrates between Maximum Power Point Tracking (MPPT) and voltage regulation into a single algorithm. All the simulation for the comparative analysis is done using MATLAB/Simulink applications. To get in depth comparison
between each control techniques capability, dynamic condition are also simulated validate the control techniques performance under real-world scenarios. From the simulation results, it reveals that while both control techniques effectively regulate DC voltage, POVR demonstrates a better performance in dynamically adjusting to changing irradiance and load conditions resulting to more efficient system. In dynamic load condition test, POVR able to retrack the 𝑉𝑟𝑒𝑓 instantaneously at each load transition. While for PI controller, the tracking time to retrack the 𝑉𝑟𝑒𝑓 is longer which ranging from 0.218 s to 0.464 s at each load transition. The only downside of the POVR control is the higher oscillation produced caused by its algorithm comparing to PI control which are analysed in the voltage regulation test where the percentage of output voltage ripple for POVR ranging from 0.066% to 5.069% while for PI ranging from 0.071% to 0.073% at different irradiance levels. Hence, these findings highlight the importance of integrating MPPT with voltage regulation to address the challenges of standalone PV systems, ensuring reliable and efficient energy supply.