Eddy Current Braking-An Auxiliary Brake in Electric Vehicles

Abstract

Braking systemsare critical in any vehicles, including electric vehicles. But, the excessive use of friction brakes results in decreased braking performance and system degradation. Regenerative braking which is widely used in EVs to recover kinetic energy during deceleration, converting it into electrical energy for storage. However, this system becomes inefficient when the battery is fully charged (90-100 %) and unable to store additional energy. Moreover, regenerative braking may not provide sufficient braking force at certain speeds, requiring traditional friction brakes, which leads to increased wear and maintenance. One alternative solution is to use eddy current braking (ECB). Due to the uncertain characteristics of ECB in low speed range integration of eddy current braking as an auxiliary to regenerative braking in electric vehicles (EVs) is suggested. Unlike regenerative braking, eddy current brakes are independent of the battery’s state of charge and offer consistent performance. Real-time speed feedback from a sensor enables dynamic adjustment of the braking force, ensuring effective braking at varying speeds. Experimental results validate the theoretical model, demonstrating efficient braking performance with minimal energy loss. The proposed system provides a non-contact, maintenance-free alternative to mechanical braking, enhancing braking efficiency and safety in EV applications. Additionally, a comparative analysis is conducted between the ECB system and existing braking mechanisms in two-wheelers, evaluating factors such as energy efficiency, braking force, and maintenance requirements. This system aims to design, simulate, and test an integrated system, improving braking efficiency, enhancing safety, and reducing mechanical wear across various operating conditions.

Introduction

Braking systems are vital for vehicle safety, especially in challenging terrains like hills. Traditional mechanical brakes rely on friction, which causes wear, noise, maintenance issues, and reduced efficiency due to overheating (brake fading). Electric vehicles (EVs) commonly use regenerative braking, which recovers energy but is less effective at high speeds, necessitating a supplementary braking method.

This study proposes an Eddy Current Braking (ECB) system as an auxiliary brake for EVs. ECB uses electromagnetic induction to create braking forces without mechanical contact, reducing wear and maintenance. The system features a DC-excited coil near a rotating metallic disc on the vehicle shaft. When current flows through the coil, it induces eddy currents in the disc, generating opposing magnetic fields that slow the vehicle.

A proportional-integral (PI) controller regulates the coil’s excitation current via a buck converter, adjusting braking force dynamically based on vehicle speed to optimize performance.

The experimental setup uses an aluminum disc for its favorable balance of conductivity, weight, cost, and corrosion resistance compared to copper. Key design considerations include coil parameters (number of turns, wire gauge, core material) to maximize magnetic field strength and braking force.

The system’s closed-loop control uses sensors to monitor speed and current, allowing real-time adjustments for efficient braking with minimal power loss. Overall, the ECB system aims to enhance EV braking by providing reliable, wear-free deceleration that complements regenerative braking, improving safety and energy efficiency.

Conclusion

An improved braking system strategy to be implemented in electric two-wheelers is presented in this work. Braking force is formed using the principle of electromagnetic induction, thereby generating the sufficient eddy current which opposes the wheel rotation. Excitation current is estimated using the controller circuit which gets input from the speed sensors and current sensors mounted on the disc. Conventional braking systems produce fixed force for different speeds. In ECB’s the road conditions are also taken into consideration. The PWM technique based control provides better braking performance. Cumulative drive performance is stable and suitable for designing in an Electric two-Wheeler.

References

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Copyright

Copyright © 2025 Afna ., Aiswarya C R, Neha Elizabeth Sabu, Surjith S, Kavitha Issac, Reenu George. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.