Modeling and simulation of power flow in an electric scooter for energy storage through regenerative braking using ultracapacitors and lithium-ion batteries
Abstract
For electric vehicles to become practical, battery life and vehicle driving range must be improved. Battery life is reduced by both large current flow and frequent charging or discharging. Ultracapacitors' ability to accept numerous charging and discharging cycles with good efficiency make them desirable for use in electric vehicles. Since ultracapacitors cannot store nearly the amount of energy as a battery, they must be used in combination with batteries. The use of ultracapacitors along with batteries and DC-DC converters allow energy storage during regenerative breaking of the vehicle. Energy stored in this way can be used later during acceleration of the vehicle. Using ultracapacitors in conjunction with batteries prolongs battery life and extents the range of the vehicle. In this thesis, flow of power to and from an electric scooter during acceleration and deceleration is simulated using Simulink®. Simulation results show how the current demand is shared by the battery and the ultracapacitor during acceleration as well as give an idea of how the energy is fed back to the ultracapacitor during deceleration. Boost or buck-boost converters are activated during the process depending on the flow of power. A control mechanism for these converters is developed and simulated. Simulation results show how the energy delivery/storage is affected by the state of charge of the ultracapacitor. A BLDC motor is also simulated based on the motor parameters of the scooter. Results obtained from these simulations will enable the implementation of a regenerative braking system that uses ultracapacitors for the electric scooter.
Degree
M.S.E.
Advisors
Kozel, Purdue University.
Subject Area
Electrical engineering|Energy
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