Abstract:
The increase in the combustion of fossil fuels to meet the growing demand for energy
is one of the main causes for the increase in the concentration of carbon dioxide (CO2)
in the atmosphere. In an attempt to slow this growing environmental pollution, the vast
majority of the world’s nations have committed to reduce emissions of CO2 and other
greenhouse gases. With this in mind, the transition from combustion vehicles to electric
vehicles (EVs) is seen by many authors as one of the most promising developments for
reducing greenhouse gas emissions and improving air quality. However, the biggest obstacle
to the popularization of this type of vehicle is the time needed to recharge its batteries,
during a trip for example. Having said all these paradigms, this dissertation presents the
development of a three-phase fast charger for electric vehicle batteries. Nominally this
charger is designed to deliver up to 50 [kW] and 100 [A] nominal to the battery. The first
charging stage consists of an AC/DC converter coupled to an LCL filter and connected to
the power grid at 220 [V] Phase-Phase. The second stage consists of a DC/DC interleaved
converter, which is connected to the DC bus at 500 [V]. The charger is coupled to the
battery in order to validate charging through the CC-CV method (Constant Current -
Constant Voltage). The operation of the converter and its control technique are validated
through simulations in the Matlab software, using the Simulink tool. Then, the charger
is built using the AC/DC first stage and its operation is demonstrated using a bank of
batteries. The control strategy is implemented in the DSP TMS320F28379D from Texas
Instruments, using the software Code Composer. Satisfactory results were obtained in the
battery charging control although the practical implementation is done on a small scale,
the control system can be easily used at higher powers, just with adjustments in the control
gains. The importance of compensating the dead-times that appear in the practical part is
highlighted.