Control strategy optimization and test for parallel hybrid electric vehicles

An efficiency model for parallel hybrid electric vehicles is set up, based on the engine efficiency map, motor/generator efficiency map and battery efficiency map. The efficiency of hybrid powertrain is defined as the wheels output power divided by the total output power from engine fuel tank and/or equivalent fuel tank of battery. An optimization control strategy is proposed to decrease the fuel consumption of vehicles. The main optimization target is to maximize the overall efficiency of hybrid electric vehicles at the charging and discharging mode, and the effect of regenerative braking and battery state of charge are also considered in the optimization model. The optimal engine torque and motor/generator torque are obtained with the different battery state of charge, engine/motor/generator speed and wheel driving power. A test bench for the hybrid powertrain was built. And the control tests of engine starting, motor assisting, battery charging and regenerative braking were carried out based on the rapid control prototyping (RCP) technology of the real time simulation system of dSPACE. The actual control effects of the control algorithm for hybrid powertrain and the validity of simulation model are verified.