DESIGN AND ANALYSIS OF BI DIRECTIONAL DC-DC CONVERTER FOR ELECTRIC VEHICLE

Abstract

The rapid growth of electric vehicles (EVs) has increased the demand for efficient power electronic converters capable of improving battery performance, energy utilization, and vehicle efficiency. Among the various power conversion techniques, the bidirectional DC–DC converter plays a vital role by enabling controlled power flow between the battery and the DC motor during both motoring and regenerative braking operations. This bidirectional power transfer enhances battery utilization, extends driving range, and improves the overall efficiency of the electric vehicle. This project presents the design and analysis of a bidirectional DC–DC converter for electric vehicle applications using MATLAB/Simulink. The proposed system consists of a lithium-ion battery, a bidirectional buck–boost DC–DC converter, a PWM switching circuit, a fuzzy logic controller, and a separately excited DC motor. During the motoring mode, the converter operates in boost mode to supply the required voltage to the motor. During regenerative braking, it operates in buck mode, allowing the recovered energy to be transferred back to the battery for charging. A Fuzzy Logic Controller (FLC) is employed to regulate the converter duty cycle and ensure stable voltage, reduced current ripple, fast dynamic response, and efficient battery charging and discharging under varying operating conditions. The proposed controller improves converter performance compared to conventional control methods by providing better voltage regulation and enhanced system stability. The complete system is modeled and simulated in MATLAB/Simulink, and the performance is evaluated through battery state of charge (SOC), battery voltage, battery current, armature current, field current, electromagnetic torque, motor speed, and converter output characteristics. The simulation results demonstrate efficient bidirectional power flow, improved energy recovery during regenerative braking, stable DC bus voltage, and reliable motor operation.The proposed bidirectional DC–DC converter with PWM-based Fuzzy Logic Control offers an effective solution for highefficiency electric vehicle power management by reducing energy losses, improving battery life, and enhancing overall vehicle performance.