2020 Electrical Power, Electronics, Communications, Controls and Informatics Seminar (EECCIS) 132 978-1-7281-7109-8/20/$31.00 ©2020 IEEE Application of Relay Feedback with Sliding Mode Control for Buck Converter System Yusril Fatahilmi Electrical Engineering Department Brawijaya University Malang, Indonesia yusril1211@student.ub.ac.id Muhammad Aziz Muslim Electrical Engineering Department Brawijaya University Malang, Indonesia muh_aziz@ub.ac.id Abstract— The Power Electronic Converters (PEC) system is an electromechanical device for electrical conversion. It has various control methodologies including linear control and non-linear control. One of the PEC systems is the Buck Converter which has the main task of controlling the output voltage. One of the problems in Buck Converter is its loop stability. The Switching control in Buck Converter uses a high frequency that can damage components and MOSFET switch on Buck Converter. Buck converter voltage is controlled by regulating Pulse Width Modulation (PWM) in the frequency-domain. The switching process uses high-frequency signals which may lead to instability to the system. This paper presents an application of relay feedback with sliding mode control (SMC) to improve the performance of the Buck Converter. An analysis and simulation by the schematic diagram of relay feedback were performed in this work. The purpose is to find the best control parameter for relay feedback. Experimental results and their corresponding analysis in term of control specifications are discussed thoroughly in this paper. Keywords— buck converter, sliding mode control, pulse width modulation, relay feedback I. INTRODUCTION Rapid technology development has an impact on the increase in energy consumption such as renewable energy. Renewable energy industry is growing widely due to energy crisis, environmental pollution, and global warming. The energy crisis increases significantly due to the availability of fossil fuel [1]. Besides that, reliable power electronics systems are continuously rising such as solar power, wind power, and energy storage systems (ESSs) [2]. Since energy sources for renewable energy is fluctuating, the output voltage level will also be varying. It makes direct usage for an electrical device not possible [3]. This encourages innovation to develop a technology of energy transmission such as power electronic converters. Power electronic converters (PEC) systems are an electromechanical device for electrical conversion. There is a function to regulate a voltage more stable with various control methods including linear and non-linear control. One of the topology of power converters is DC-DC converter. DC/DC converters are common device to achieve energy conversion and management. DC/DC converter can be used to obtain a stable voltage with a buck or boost method [4]. The control of the DC-DC Converter is to regulate output voltage under a change in input voltage and track the error desired from the reference voltage [5]. Voltage regulation of a DC chopper is made by fast switching using semiconductor components. One of the topologies DC/DC Converters is Buck Converter. There is a function to reduce a DC voltage [6]. Buck Converter is non-linear and varies in time. One of the problems in Buck Converter is switch control [1]. The switching control in Buck Converter has an unlimited movement that uses high frequencies. Uncontrolled high frequencies can damage the MOSFET switch and components of the Buck Converter. Traditional controllers used in Buck Converters such as voltage mode and current mode controllers require careful compensators to achieve good stability and transient responses. The switching control of DC/DC Converter is performed by adjusting the time on (T on ) and time off (T off ) in the frequency domain. The PWM method is a modulation technique by changing the duty cycle with a fixed amplitude and frequency value. The voltage control in load is regulated by adjusting the time on (T on ) while the period is maintained at a constant value. According to [7] The operation of high- frequency converter PWM needs small values of Resistance (R), Inductance (L), and Capacitance (C) for easier integration with active silicon components. The function of Resistance value (R), Inductance value (L), and Capacitance value (C) are to control the switching frequency and duty cycle in the operation of the digital-analog converter. Sigma-Delta Modulators (SDMs) is one of the analog- digital converters that has a high resolution of digital controllers. Sigma Delta Modulator is a feedback control that used in a discrete system and ensures the conversion in frequency sampling that has a power conversion standard. Sigma-Delta Modulator uses the integrator function to provide an incremental action as an analog integrator in a continuous-time instance [8]. Sigma-Delta Modulator adapts the sign (e) function into a digital signal with a value between 0 and 1. Sigma Delta Modulator is also called a relay control system, which has a controlled object and has a relay control force y = sign (e) that aims to reject interference. The Relay Feedback Control trial method performed using closed-loop control requires the selection of appropriate relay parameters to be able to process the output response to remain close to the set-point value [9]. The switching process that uses high frequency produces chattering which results in instability in the system. Sliding Mode Control (SMC) is a linear control that is widely used with dynamic systems that have high resistance [10]. SMC has a boundary layer (BL) method on the sliding surface which creates smooth control inputs and system boundaries below the layer. Boundary-Layer in the control system is done by replacing the sign (e) Function which has a positive saturation and positive constant value. Sliding Mode Control (SMC) application is needed to reduce the chattering response that uses the boundary layer (BL) method by testing the Relay Feedback control system. Authorized licensed use limited to: Universitas Brawijaya. Downloaded on December 10,2020 at 06:50:54 UTC from IEEE Xplore. Restrictions apply.