Energy Management Strategy with Regenerative-Breaking Recovery of Mixed Storage Systems for Electric Vehicles

Abstract

The present paper addresses the energy management (EM) strategy between batteries and ultracapacitors (UCs) in a dual-propulsion urban electric vehicle (EV). The use of two propulsion machines proves advantageous for high-performance EVs facing spatial constraints. Allocating load power requirements among the propulsion machines and energy storage components poses a significant challenge in this design. In this paper, the control strategy presents managing the energy flow between the converters and the two brushless DC motors (BLDCs) motors via the DC link in order to maintain the energy demand of the EV coming from the dynamics of the latter. For this, power control is carried out by a management algorithm. This management is based on the power requested/generated by the two machines (BLDCs), the state of charge of the batteries (SOCBat) and the state of charge of the ultracapacitors (SOCUC). The bidirectional DC-DC converter is controlled with current to ensure the functioning of the motor or the generator of the vehicle. We also integrate the controls of the DC bus and BLDC. Additionally, the recovered energy during braking is stored in the battery or in the UC depending on the operating conditions.