Design of sliding mode controllers for power converters in electric vehicles

Abstract

Power converters and its controller play a substantial role in power transfer of electric vehicles newlinewith guaranteed stability and performance. Power converters in electric vehicles are newlineprimarily utilized to charge the battery pack and drive the motor. The onboard chargers are newlinegaining increasing attention in transportation electrification considering the charging convenience newlineand flexibility. To guarantee the stable performance of the battery, a two-stage newlinetopology is adopted for the onboard charging with an active front end AC-DC converter newlineand a bidirectional DC-DC converter. The AC-DC converter is designed to provide unity newlinepower factor operation and to meet the standard limits of harmonic content and total harmonic newlinedistortion (THD). The DC-DC converter is designed with bidirectional property, newlinesince it is used for both charging and traction purpose. To extend the life of the battery newlinetight regulation of voltage and current is maintained for both charging and discharging newlineoperations. One of the major challenges in developing onboard chargers is the design of newlinerobust control strategies capable of mitigating the grid current harmonic content and regulating newlinethe voltage and current both at DC bus and battery side. In this work, sliding mode newlinecontroller (SMC) is designed to provide robust performance against unmodeled dynamics, newlineinsensitivity to parameter variation, external disturbance rejection and to provide fast newlinedynamic response. The performance of the electric vehicle onboard battery charger can be newlineenhanced by implementing sliding mode controller for power converters. The challenge newlinein selecting the sliding mode parameters can be addressed by using optimization techniques. newlineMetaheuristics optimization algorithms are adapted for sliding mode parameter newlineselection based on their potential to solve complex optimization problems characterized newlineby system uncertainties. The size and weight of the onboard chargers can be reduced by newlineusing transformerless power converters.