The Control Strategy of Flywheel Battery for Electric Vehicles

Electric vehicles (EVs) are the ideal road transportation tool to mitigate air pollution and carbon dioxide emissions. However the current energy sources are not qualified for EVs on energy density, power density and cycle life. Flywheel battery is a new concept battery for storing energy in mechanical form, it offers some attractive advantages as compared to chemical battery for EVs, such as high energy and power density, long cycle life and reduction of maintenance. Considered the high energy density of battery(Lead-acid) and the high power density of flywheel battery this paper proposed a complex energy sources for EVs based on battery and flywheel battery. Established the model of flywheel battery and proposed the charging and discharging control strategies of it. During the charging process combined Fuzzy-PI controller was used, and at the discharging process, the pulse width modulation (PWM) technique was used to control the output voltage and power of flywheel battery to meet the driving motor's requirement. The results showed that the flywheel battery had good charge and discharge dynamic response.