| Considering the energy consumption and specific performance requirements of mining trucks,a coaxial power-split hybrid powertrain system(CPSS)is proposed in this paper,which is composed of two sets of planetary gears,and a clutch.However,one-mode structural cannot always guarantee the motor operate in high-efficiency region,and the planetary gear set is still complex and quite expensive.And so a novel multi-mode transmission system(MMTS),which is composed of one planetary gear set,and a parallel transmission structure,is proposed.Due to the presence of the clutch may cause additional power loss of the hydraulic system and increase system complexity,therefore,a novel uninterrupted multi-speed transmission(UMST)is proposed,and the optimal shift control strategy and energy management strategy are studied.All in all,the key novel contributions include the following:A hybrid vehicle model based on a rule-based control strategy is established to evaluate the fuel economy.The simulation results indicate that the proposed CPSS is superior to the Toyota Hybrid System(THS)and the conventional mechanical vehicle system.To evaluate the fuel economy accurately,dynamic programming(DP)is used to calculate the global optimum solution.Compared to the conventional mechanical vehicle system and THS,the proposed MMTS can improve the fuel economy by 10.08%and 3.42%under the giving driving cycle,respectively.The combination of the power-split device and three-speed lay-shaft transmission can realize uninterrupted gear shifting with the proposed shift strategy,which benefits from the proposed adjunct function by adequately compensating the torque hole.Due to the "dimension curse" of DP,a real-time control strategy is designed in this paper.The simulation results demonstrate that the proposed uninterrupted multi-speed transmission with DP and real-time control strategy can improve fuel efficiency by 11.63%and 8.51%compared with conventional automated manual transmission system,respectively.In order to achieve fast torque coordination while guaranteeing the driving comfort performance,the torque profiles of the power split device and the traction motor are optimized by Linear-quadratic regulator(LQR)algorithm.A modified Gaussian distribution function is proposed to punish shift times due to the impact of the road slope.As efficiency-oriented energy control strategy would result in frequent gear shifts,to achieve a desirable tradeoff between the overall efficiency and the shift stability,multi-objective genetic algorithm(MGA)is integrated to optimize the overall performance.The simulation results reveal that the proposed improved real-time control strategy(IRTCS)with MGA can reduce shift frequency by 70.78%to improve the drivability,only sacrificing 4.86%of overall efficiency compared to that of DP.In this paper an integrated system,which includes an uninterrupted dual input transmission and hybrid energy storage system,is proposed to improve energy efficiency and extend battery lifespan.Given the limitations of dynamic programming in practice,a real-time optimal control strategy is designed to evaluate the power loss and battery capacity degradation.To achieve a desirable trade-off between battery degradation,energy consumption,and acquisition cost,a mixed-integer multi-objective genetic algorithm is implemented to optimize the parameters of the hybrid energy storage system.The simulation results reveal that the proposed integrated system shows the potential of saving 15.85%-20.82%of the energy consumption in typical driving cycles and more than 22.61%-31.11%Life-cycle cost compared with the single-ratio transmission-based battery electric vehicles.The selected Pareto front can further enhance Life-cycle cost from 26.53%to 28.13%in the HWFET cycle.Given that both fuel consumption and transport time influence transport costs of mining trucks,an energy management strategy(EMS)based on velocity optimisation is proposed and illustrated on a series hybrid electric mining truck in this study.Compared to the results under the known driving speed cycle,the proposed EMS can enhance fuel economy by 26.59%under the guarantee of same transport time,or transport time can be reduced by 42.4%without sacrificing the fuel consumption.Therefore,the proposed velocity optimisation strategy can reduce transport costs for mining enterprises significantly. |
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