Design And Optimization On The Control System For Auxiliary Power Unit Of Extended-Range Electric Vehicle

The Extended-Range Electric Vehicle(EREV)is a feasible and provisional solution for the problem of short driving range of electric vehicles.It is especially suitable for the city bus with fixed traffic conditions to play the advantages of energy saving and environmental protection.Based on the characteristics of urban traffic conditions,this paper designs the Auxiliary Power Unit(APU)to provide better power with economical oil.A generator and an engine of are selected after screening and matching.Based on the results of selection,the simulation with ADVISOR software is carried out,which verifies that the selection results meet the design requirements.And the APU model based on the power flow has been set up in the Simulink environment.In order to further develop EREV's energy-saving advantage,this paper compares three kinds of energy management strategies by stimulation,which are based on the fixed rules,and combines the advantages of the three to achieve an advanced energy management strategy.To realize the strategy,this paper designs two APU control strategies and selects the constant speed control strategy finally by simulation and comparison.Meanwhile,engine speed control-generator torque control coordinated control scheme is determined.Engine speed control is relatively complex.Therefore,this paper designs the fuzzy control and PID control.Fuzzy control process is too complex to adjust to the best control state,but PID tuning process is very simple.As the simulation results show that the control effect of PID is quite similar to that of fuzzy control,this paper prefers the PID control,which is relatively easy to be implemented.To verify the reasonability of the control strategy and the feasibility of the speed PID control,the paper constructs an experiment bench.After testing on site,it sets the KP,Ki values and the control cycle of PID control and explores the influence of conditions of factors on the result of PID control.What's more,the APU control strategy of fixed speed adjusting torque is proved to be feasible after being carried out on the test bench.