New booster motor design supports safer brake-by-wire systems for intelligent electric vehicles

Brake-by-wire systems are becoming a core technology for intelligent electric vehicles, but their performance depends heavily on a compact, reliable and responsive booster motor. A study in Green Energy and Intelligent Transportation presents a structured design method for the booster motor used in brake-by-wire systems, combining motor selection, electrical and mechanical design, simulation optimization and prototype verification.

Unlike conventional vacuum-assisted braking, brake-by-wire systems use electronic control and motor-driven actuation to generate and coordinate braking force. This architecture can improve braking response and support braking energy recovery, especially in electric and intelligent vehicles. It also introduces demanding engineering requirements: the booster motor must respond quickly, operate safely under continuous braking conditions, fit into limited chassis space and provide reliable assistance at automotive low voltage.

The researchers first analyzed the mainstream structures of brake-by-wire systems and the practical challenges faced by assisted motors. They compared different motor types and structures, including induction motors, permanent magnet motors and switched reluctance motors, then identified a brushless DC motor scheme suitable for booster motor characteristics. The design emphasizes high efficiency, power density, responsiveness, controllability and compatibility with the vehicle's 12 V power supply.

The study then detailed both the mechanical and electrical structures of the proposed booster motor system. The mechanical design includes components such as the shaft, motor shell, stator, rotor, fixed mount and driver board. The electrical design uses a microcontroller, three-phase MOS bridge drive circuit, Hall position sensing, displacement sensing, current and voltage sampling, and CAN communication to support motor control, diagnostics and vehicle-level integration.

To refine the design, the authors combined electromagnetic design calculation with simulation analysis using Ansys Electronics Desktop and Matlab. They designed a brushless DC motor with a rated power of 300 W and a rated torque of 1 N*m, then used finite element simulation and control analysis to optimize motor drive performance. According to the paper, the resulting optimization scheme met the required motor performance and parameter targets.

The work also reports the actual design of a booster motor system and discusses functional-safety issues observed through simulation and experiment. This makes the contribution more than a theoretical comparison of motor types: it offers an engineering pathway for designing the key actuator that links brake-by-wire control commands to reliable braking force.

For intelligent electric vehicles, such design work matters because braking is tied directly to both safety and energy efficiency. A well-designed booster motor can help braking systems respond quickly, coordinate hydraulic braking with regenerative braking and improve the adaptability of braking force under different driving conditions. While further in-depth study and broader validation remain necessary, the proposed method provides a useful reference for developing safer, more efficient brake-by-wire hardware.

Reference

Author:

Bumin Meng a, Zhengzhao Zhou a, Congyue Zhang b, Feifan Yang a

Title of original paper:

A design method for booster motor of brake-by-wire system based on intelligent electric vehicle

Article link:

https://www.sciencedirect.com/science/article/pii/S2773153723000464

Journal:

Green Energy and Intelligent Transportation

DOI:

10.1016/j.geits.2023.100110

Affiliations:

a The School of Automation and Electronic Information, Xiangtan University, Xiangtan 411105, China

b School of Mechanical Engineering, Xiangtan University, Xiangtan 411105, China

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GREEN ENERGY AND INTELLIGENT TRANSPORTATION