PERFORMANCE EVALUATION OF AN ELECTRIC VEHICLE INTEGRATED WITH REGENERATIVE BRAKING SYSTEM USING PI CONTROLLER

Abstract

Battery electric vehicles (BEVs) without regenerative braking mechanisms often suffer major drawbacks of limited driving range. Although extensive research works exist in electric vehicles integrated with regenerative braking, the performance evaluation of an electric ambulance, in the context of aerodynamic as well as energy recovery assessment from a complete vehicle modeling perspective based on the difference between the controlled dynamic speed and the drive cycle reference speed is not well reported. To compensate for the problem mentioned above, this paper aims to evaluate the performance of an electric ambulance (EA), integrated with a regenerative braking system (RBS) in comparison to an EA without a regenerative braking system (No RBS), in terms of aerodynamic drag coefficient values, state of charge (SOC), endurance efficiency, statistical correlation and mean absolute error (MAE) using proportional-integral (PI) controller. The SOLIDWORKS and SOLIDWORKS Flow Simulator were used to develop the EA CAD model and conduct aerodynamic analysis. MATLAB Simulink was used to model the EA complete EA system. The EA drive system was evaluated using three drive cycles (UDDS, FTP, and US06). The EA had an aerodynamic coefficient of 0.29. From the perspective of energy recycling, the EV-RBS yielded an extended drive range and appreciable gain in state of charge compared to EV-No RBS on the mentioned drive cycles. Generally, as the deceleration frequency increases from one drive cycle to another, the energy recycling increases, and the range increases correspondingly. In addition, the PI controller, which relied on speed error as a means of regulating the controlled speed, was found to be efficient, as the controlled speed was highly correlated to the reference speed. Overall, very low mean absolute errors in the vehicle speed were observed for the drive cycles considered.