Modeling and Control of Bidirectional DC-DC Converters for Electric Vehicle Battery Management and Energy Recovery Systems

Abstract

The increased usage of electric vehicles (EVs) has escalated the demand of effective power management systems that guarantee ideal usage of batteries, efficient power restoration and unsympathetic performance with contemporary mobility requirements. The core of this task is the two-way DC-DC converter, which makes it possible not only to transfer power between the traction battery and the auxiliary loads but also during regenerative braking to recover energy. In this paper advanced model-based control and modeling are developed to understand the analysis of a bidirectional DC to DC converter used in EV battery management systems and energy recovery systems. To include dynamic characteristics based on operating modes, that is, during buck (charging), boost (discharging) and regenerative braking, a state-space averaged model is obtained. A two-loop control system where sliding mode control is applied to the current control loop and proportional-integral regulation is applied to the voltage loop is suggested to compensate all the disturbances and the ability to control the state-of-charge (SOC) with high precision. Simulation outcomes under the New European Driving Cycle (NEDC) indicate that the converter has a high efficiency of 95% peak efficiency, rapid transient behavior with a settling time that is less than 5 ms and effective SOC control to within safe operating regions, able to recover up to 23.5% of braking energy. The quality of efficiency, stability, and battery protection of the proposed strategy is also proven in comparing it to other available control methods. The results identify bidirectional DC-DC converters as a key to future EV battery management, higher energy efficiency, driving range, and future vehicle-to-grid capability.