Electric Energy Management Of Fuel Vehicles Based On The Super Capacitor And The Solar Panel

In China, the vast majority of autos are fuel vehicles, in which, almost all of them uses lead-acid battery. Since there is still a long distance from fuel vehicles to electric vehicles and lead-acid battery follows lots of shortcomings, such as limited life, heavy metal pollution, low efficiency of starting up at low temperature, electric apparatus perform poorly and so on, this kind of battery should be replaced as quickly as possible. The super capacitor exactly overcomes the disadvantages from the above battery. Therefore, on the one hand, the battery will be tried be replaced by super capacitor in the dissertation. On the other hand, the super capacitor will be connected to a solar panel to avoid loss of capacity.At-20℃, only traditional battery and super capacitor are tested separately as a auto’s auxiliary energy supply. The result shows that super capacitor can start up the starter successfully in 2 seconds, but the battery cannot in 5 seconds. Then the capacity of the super capacitor should be 1750 F after an analysis. And the solar panel’s output voltage should be bigger than 8V to avoid the auxiliary energy decreasing.Established the solar panel’s model in the Simulink and implemented a perturbation and observation method based duty circle in the MATLAB to achieve MPPT. The result shows that in general, the output voltage is higher than the super capacitor’s rated voltage 8V, which proves this subsystem had been designed successfully.In order to stabilize the bulbar voltage and avoid the over discharge, determined the procedure that starting based on the bulbar’s voltage change and terminating based on the super capacitor’s voltage. All exact parameters of the bidirectional DC-DC converter were calculated in order to keep it in CCM. The transfer functions of the buck and the boost model were deduced separately. Then designed compensators to keep constant current charge when bucking and achieve the bulbar voltage stability with a enough current. In the end, make several simulations of all the model and process in the MATLAB, which proves the reliability of the system. The dissertation provides a new idea for the design of fuel vehicle’s auxiliary energy.