1 THE EFFECTS OF VARYING THE DUTY CYCLE TO THE OUTPUT VOLTAGE IN BUCK CONVERTER Nurhazwani Binti Saleh Department of Electrical Engineering Politeknik Merlimau nurhazwani@pmm.edu.my ABSTRACT This research investigates the influence of variation duty cycle on the output voltage of buck converters. The high DC voltage is transformed into a low voltage value using a DC-to-DC buck converter. By varying the duty cycle, the performance of a buck converter in terms of output voltage is obtained and analysed. There have been four different values of duty cycle tested. In order to analyse the effects, a simulation is conducted. The converter circuit was constructed and simulated using MATLAB Simulink. The circuit made up of components such as a switch/IGBT, capacitor, inductor, and resistor. The findings of this investigation have been recorded, and it has been demonstrated that the increasing of the duty cycle will contribute to an increase the output voltage. keywords: Buck converter, duty cycle, MATLAB, Simulink. 1. INTRODUCTION Convertors are commonly employed in modern electronic applications nowadays. Converters are found used in a variety of portable devices, including laptops, smartphones, tablets as well as application in power systems such as flexible AC transmission systems and high-voltage DC (HVDC). It also becomes an important part of modern micro grids and energy storage systems (Jung, Kim, Moon, & Lee, 2018). According to (Biswas, Majhi, &Nemade, 2021), a DC-to-DC buck converter is widely used in a variety of non-isolated type applications such as battery chargers, voltage regulator modules for microprocessors, telecommunication, power systems, LED drivers, and automotive applications due to its simple structure and cost-effectiveness. In addition, converters are frequently used in renewable energy-based applications (Baharudin, Mansur, Hamid, Ali, & Misrun, 2018). In recent years, a significant number of researchers have been focusing their attention on the generation of power using renewable technologies such as solar systems. In order to utilise the photovoltaics for delivering power to specific loads, the output needs voltage conversion (Ettappan, Maheswaran, Vimala, Somasundaram, & Vishnupriyan, 2021). As a consequence of this, the buck converter has indirectly become one of the researcher’s concerns as well. Buck converter is used to decrease the voltage from the source, as a solar panel need to charge the power of battery at the certain voltage (Zulkifli, Azri, Alias, Talib, & Lazi, 2019). The buck converter acquires the highest efficiency among other DC conversion techniques (Ghani et al., 2019). Therefore, battery lifetime can be safe, and also other electronic devices which use Buck Converter (Cristri & Iskandar, 2017)