Research On Energy Management Control Strategy Of Hybrid Wheel Loader

The wheel loader have an irreplaceable position in construction machinery because of its wide operation range.However,its high fuel consumption and serious emissions lead to serious energy and environmental problems.The fuel consumption and emissions can be reduced by improving the capacity of loader’s braking energy recovery and reuse.In order to improve the capacity of recovering and reusing braking energy,the configuration for fuel-electric-hydraulic hybrid system of wheel loader and energy management control strategy are proposed.The main content and results are as follows.(1)The configuration for fuel-electric-hydraulic hybrid system of wheel loader is proposed.Based on the typical operation mode of the wheel loader,the composition,advantages and disadvantages of the power system for electric drive loader are analyzed.In order to improve the braking energy recovery capacity and dynamic performance of the electric drive loader,as well as reduce its fuel consumption,the configuration for fuelelectric-hydraulic hybrid system of wheel loader is proposed.A hydraulic pump/motor and a accumulator are connected in parallel to the front axle of the electric drive loader.(2)The energy management control strategy is built.The working conditions of the loader drive motor and hydraulic system of fuel-electric-hydraulic hybrid system are analyzed under the V-type working mode.The wheel loader is started by the hydraulic system to avoid motor blockage and improve the dynamic performance when the loader speed is low or the resistance is high.The braking energy is recovered by the hydraulic braking system when the loader speed is low or the super capacitor SOC value is high.The braking energy is recovered by the electric braking system and the hydraulic braking system when the braking intensity is high.The energy management control strategy can improve the dynamic performance and the ability of braking energy recovery of the fuelelectric-hydraulic hybrid wheel loader,and reduce fuel consumption.(3)The simulation models of wheel loader hybrid system and control system are built.A simulation model of the fuel-electric-hydraulic hybrid system is built according to the composition of a loader.A control system model is built according to the energy management control strategy.Besides,A joint simulation model of fuel-electric-hydraulic hybrid wheel loader based on the AMESim&Matlab/Simulink platform is built.(4)Simulation and analysis under multiple working modes are completed.According to the typical working modes of the wheel loader,a variety of working modes are designed.And the joint simulation of fuel-electric-hydraulic hybrid wheel loader under different modes is completed and analyzed.The simulation results show that the energy management control strategy can effectively recover the braking energy of the fuelelectric-hydraulic hybrid wheel loader,and use the energy when the loader starts.Compared with the electric drive loader,the braking energy recovery capability and fuel economy of the fuel-electric-hydraulic hybrid wheel loader are improved.