Modelling of energy recovery in electric vehicles for various braking scenarios on changing road surfaces

Abstract

Due to great braking energy losses caused by traffic jams, changing velocity, and frequent start-stop modes, recovery of braking energy has become a top priority. In this paper, the universal braking system is described that operates at various driving scenarios including smooth braking and emergency antilock braking on different road surfaces and integrates both the friction and the electric braking strengths. The vehicle model reflects multiple factors, such as air resistance, road slope, and variable friction. The refined tire model recognizes changing road surfaces at different velocities. In the motor and battery model, the state of charge and electric current/voltage restrictions of the hybrid energy storage are taken into account. Braking torque generated by the Sugeno’s fuzzy logic controller established in the Simulink environment is allocated between friction and electric brakes. Often cited torque oscillations at low vehicle velocities have found their description, being reduced and evenly distributed throughout the braking process with the help of torque stabilisation loop. The outcomes of this study can be considered in the design of braking systems for electric vehicles with superior energy recovery capacity.