Regenerative Braking Systems in Electric Vehicles

The role of electric vehicles in transitioning to eco-friendly and sustainable transportation systems is increasingly growing. In this context, regenerative braking is a key technology that converts the vehicle’s kinetic energy into electrical energy and feeds it back into the battery.

Rising environmental concerns and the problems caused by dependence on fossil fuels have made alternative and environmentally friendly mobility solutions necessary. Electric vehicles stand out with their advantages of zero emissions and low energy consumption. In the development of this technology, recovering kinetic energy in an efficient manner is critical for improving energy efficiency and extending driving range. Regenerative braking converts the kinetic energy generated during deceleration into electrical energy and transfers it to the battery. This process not only conserves energy but also optimizes the performance of braking systems.

Regenerative Braking System

Regenerative braking is based on the principle that, in electric vehicles, the motor operates in reverse to convert the vehicle’s kinetic energy into electrical energy and feed it back into the battery. When the brake pedal is pressed, the vehicle’s motor functions as a generator, transforming kinetic energy into electrical energy.

Normal driving condition

• Electric vehicles operate under normal conditions by drawing energy from the battery to propel the vehicle forward.

Braking moment

• During braking, the motor operates in reverse to convert kinetic energy into electrical energy, which is then fed back into the battery.

Thanks to this principle, especially during downhill descents or in stop-and-go traffic:

• Energy recovery is achieved,
• The load on mechanical braking systems is reduced,
• Fuel efficiency improves and emissions decrease.

Braking Systems in Electric and Hybrid Vehicles

In electric and hybrid vehicles, braking strategies are achieved through the integration of regenerative and mechanical braking systems. In this context, three control strategies stand out:

Series Braking – Optimal Pedal Feel

In the Series braking system, the distribution of braking forces between front and rear wheels is arranged to provide the driver with an optimal braking feel. When a command is applied to the brake pedal:

• Under low deceleration demands, only regenerative braking is activated,
• If the required braking force exceeds the available regenerative capacity, additional mechanical braking is engaged.

This approach prioritizes safety during sudden braking while maximizing energy recovery performance.

Series Braking – Optimal Energy Recovery

The goal of this strategy is to convert as much kinetic energy as possible into electrical energy and feed it back into the battery. The system’s operating principle can be summarized as follows:

• The commanded deceleration rate is limited according to road adhesion coefficients.
• Regenerative braking is prioritized to meet the required braking force;
• When necessary, mechanical braking supplements the braking force to complete the demand.

This approach optimizes energy recovery while ensuring safe braking.

Parallel Braking System

In the parallel braking system, regenerative and mechanical braking are applied simultaneously. In this system:

• Traditional mechanical braking distributes braking force between front and rear wheels at fixed ratios.
• Regenerative braking provides additional braking force primarily on the front wheels, especially at low speeds, to contribute to total braking power.
• Under high deceleration, regenerative braking is disabled due to motor speed limitations, and mechanical braking takes full effect.

This arrangement plays a critical role in maintaining braking balance and safety.

With the increasing adoption of electric vehicles and growing environmental concerns, together, regenerative braking systems are coming to the forefront. The primary objective of regenerative braking is to convert the vehicle’s kinetic energy into electrical energy and recover it in the battery, thereby enhancing energy efficiency. Through the integration of appropriate control strategies, regenerative braking systems can be optimized for both energy recovery efficiency and driving comfort. These approaches will lead to significant advancements in future electric vehicle technologies in terms of sustainability and performance.