Research on Constant Current Control of Regenerative Braking in Hybrid Energy Storage Electric Bicycle

Abstract

Electric vehicle has gradually become a hot research topic due to the energy crisis and environmental pollution problems. But the traffic is becoming much more crowed because of the sharp increase in the number of private cars, for this reason, the electric bicycle has been more and more popular owing to the convenience of it, especially the electric bicycle is easier than vehicle to park, but the mileage short problem of electric bicycle is always the main factor to influence the development of electric bicycle, moreover, electric bicycles are chiefly used under urban conditions which have frequent start and stop process, so single energy source electric bicycle can not be very good to adapt to these driving conditions. So far, there is little research about the application of the super capacitor and regenerative braking system of the electric bicycle. In this paper, regenerative braking system of hybrid energy storage electric bicycle is the research object, the mathematical model of regenerative braking system of hybrid energy storage electric bicycle has been established, regenerative braking system of hybrid energy storage consists of the brushless dc motor, Buck - Boost DC-DC converter, super capacitor and controller. In order to validate the regenerative braking system model, the regenerative braking simulation test system has been designed and developed, the equivalent small power brushless dc wheel motor drive system is used to simulate the drive system of electric bicycle. The mathematical model of regenerative braking system is calculated and experimental verified, the results show that the established mathematical model is accurate and effective. In order to maintain small braking torque fluctuation range during the braking process, constant current control strategy has been employed to control the armature current. As simulation result and experiment data shows, the hybrid energy storage system can effectively absorb the regenerative braking energy. Stable braking torque can be implemented and higher energy recovery efficiency has been realized in the process by adopting the constant current control strategy.