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Investigationand Development Of Ultracapacitor Charge-discharge System Of Solar Electric Vehicle

Posted on:2011-06-18Degree:MasterType:Thesis
Country:ChinaCandidate:X Y WangFull Text:PDF
GTID:2132360308464427Subject:Vehicle Engineering
Abstract/Summary:PDF Full Text Request
Since 20th century, the automotive industry has got a great development, but at the same time it makes energy source shortage and environment pollution arising worse and worse. To solve these problems, researching and applying innovative sources in the field of automobile are attracting people's attention, such as photovoltaic and ultracapacitors. In this paper, a hybrid power system of electric vehicle (EV) based on photovoltaic cells-ultracapacitors-batteries were designed.Firstly, this paper makes an introduction and comparison to the three power component's application in EV. A hybrid system composed of batteries and ultracapacitors could combine the high power density of ultracapacitors and the high energy of convenient batteries. Aimed at improving the the performances of vehicle start-up /climbing and reducing the time of surge current discharging, the structure of hybrid power system is proposed. In this system, BOOST convertor was proposed as the Maximum Power Point Tracker (MPPT), Current Dual Quadrant DC/DC Convertor was choosed as the connection between ultracapacitor and DC bus. This paper designed the control system and the software.Secondly , hardware circuit parameters of BOOST convertor and some assistant circuits were designed ,such as IGBT module drive and snubber circuit, signal sampling and conditioning circuits of voltage, current and temperature signal, assistant power source and so on. Then, this paper proposes a novel control strategy called subsection self-adaptive algorithm to improve the tack efficiency. Next, according to analyzing the characteristic of ultracapacitor, dual quadrant DC/DC convertor were designed for the ultracapacitor used in experiments, the overall control strategy was designed based on current restriction control strategy.Finally, simulations and experiments were done to validate the designed system. From three comparative MPPT experiments, we can conclude that the MPP tracker designed with subsection self-adaptive algorithm is more efficient, the output PV power has improved by 4%-18%. And, the charge and discharge experiments of ultracapacitor show that, with dual quadrant DC/DC convertor, the charge efficiency from PV cells to ultracapacitor and discharge efficiency of ultracapacitor has also improved. Lastly, the performance experiments of EV start-up indicats that using a photovoltaic cells-ultracapacitors-batteries hybrid power system can stabilize the battery voltage, reduce surge current discharging time of battery, improve the start-up performance of vehicle, all of these have marked signification to extend the cycle life, increase the usable capacity of the battery and improve the driving range of vehicle.
Keywords/Search Tags:Solar energy, MPPT (maximum power point tracking), Ultracapacitor, DC/DC Convertor
PDF Full Text Request
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