Integrated Control of Battery and Ultra Capacitor in a EV’S With Regenerative Breaking

Abstract

This chapter proposes the centralized control of battery-powered electric vehicles as per reference torque cycle. A nonlinear control structure ensures the stable behavior of a motor in all operating modes of the vehicle. A bi-directional DC-DC converter provides an estimated power as per the requirement to load. This significantly improves battery energy utilization and regulation using ultra- capacitor-aided vehicles with regenerative braking. A 24V, 100Ahr battery, and 63F-30V ultracapacitor are sources connected through a 1kW bi-directional converter. It is driven by a gate pulse generated by a controller named Spartan6-LX9. The output of the converter is connected to a 1hp DC motor. An entire system has been verified using a battery with an ultracapacitor and the battery alone. It is proposed to improve voltage regulation and compensate for battery voltage sag, followed by SOC retention improvement. During deceleration regenerative mode, the vehicle enables power flow reversing from load power to source power, which stores the resultant braking energy into an ultra-capacitor. The speed and torque of the motor were estimated based on the driving cycle, and the same was controlled by reference load voltage and current by the RST control strategy. The proposed circuit has been simulated using Simulink and experimentally validated.