Battery-super capacitor hybrid power system for pedal-assisted electric bicycles considering energy and exercise efficiency

Abstract

Pedal-assisted electric bicycles have been developed in recent years to support people in both transportation and in exercising with the appropriate intensity. The battery efficiency is strongly affected by the bicycle operating conditions, including weight, speed, slope, cadence, and gear ratio. The pace of the exercise— cadence and torque—can also be controlled by manipulating the motor power and gear ratio. In this context, a control strategy for the motor power and gear ratio was introduced to maximize the battery and exercise efficiency. In this study, we attempt to enhance the cadence control efficacy by adopting a battery-super capacitor hybrid power system. Besides, the re-charging module was included to harvest energy from the motor when the bicycle is running downhill. With this module, the travel distance now can be extended. Our simulation show that the hybrid power system can enhance the battery efficiency by extending the short-term power capacity and reducing gear ratio changes. © 2019, Institute of Advanced Scientific Research, Inc. All rights reserved.