Research On Strategy Of Energy Management For Parallel Hydraulic Hybrid Vehicle Based On MPC

Hydraulic hybrid technology is an important branch of hybrid.It can recycle and reuseof vehicle braking energy in the process through the pump/motor, particularly adapted tothe frequent starts and stops of the urban condition.Parallel hydraulic hybrid vehicles(PHHV) have two power sources.Energy distribution between power sources relates towhether the hydraulic hybrid vehicle energy saving and emission reduction.The use of highperformance energy management strategies to achieve distribution power source of energyis more important.The traditional rules of energy management strategy is too simple and not beenoptimized, the result is not ideal.The calculation of the instantaneous optimization methodis too large.Global optimization rule needs to predict the future with the road in advance,does not apply to real-time control of the rapidly changing conditions.For this reason, studythe model predictive control (MPC), effectively combine the local optimization and rollingoptimization for power management in the case of reducing the computational load.Based on the MATLAB/Simulink platform, establish PHHV backward simulationmodel on theoretical theory modelling. The model includes the calculation model of powerdemand, transmission model, engine model, accumulator and hydraulic pump/motor modeletc.Based on the model predictive control (MPC) theory, design the MPC controller. Itsinputs are the accumulator charge state SOC and instantaneous engine fuel mass flow ratem f, output is the engine power demand proportion, the objective function is theminimum fuel consumption.The simulation results show that: MPC controller is good for energy distribution oftwo power source in the PHHV vehicle based on the UDDS driving cycle proc ess.Theconsumption fuel oil for MPC energy management strategy is0.5987gal, enhances the fueloil efficiency16%, reduces5%oil consumption compared to the rule method energymanagement strategy.The oil consumption reduces along with the accumulatorprepressurization pressure increases gradually,and the improvement of pre-compressionstress is beneficial to improve fuel economy.But the pre-pressure is greater, the greater theleakage energy.In a certain range, increasing the displacement of hydraulic pump/motorwill improve fuel economy, but beyond this range, the displacement will not affect the fueleconomy.Therefore,it is important to select the appropriate hydraulic unit parametersaccording to the actual situation.