What are the latest trends and innovations in electric power steering motor technology and applications?

1 Motor types and characteristics

EPS motors can be classified into two main types: brushed and brushless. Brushed motors use carbon brushes and commutators to switch the current direction in the coils, while brushless motors use electronic controllers and sensors to achieve the same effect. Brushless motors have several advantages over brushed motors, such as higher efficiency, reliability, durability, and noise reduction. However, they also require more complex and costly control systems and sensors. Both types of motors can be further divided into subtypes based on their shape, size, winding, and magnet configuration, such as axial, radial, inner rotor, outer rotor, slotless, slotted, permanent magnet, or wound field.

2 Motor control and feedback

EPS motors need to be controlled precisely and accurately to provide the optimal steering assistance to the driver, depending on the speed, torque, and angle of the steering wheel. This requires a sophisticated control system that can monitor and adjust the voltage, current, and frequency of the motor, as well as the feedback signals from the sensors. The sensors can measure the position, speed, torque, and temperature of the motor, as well as the steering angle, steering force, and vehicle speed. The control system can use different algorithms and strategies to optimize the performance, efficiency, and safety of the EPS system, such as pulse width modulation (PWM), field oriented control (FOC), or adaptive control.

3 Motor integration and placement

EPS motors can be integrated and placed in different locations within the EPS system, depending on the design and layout of the vehicle. The most common types of EPS systems are column-assist (C-EPS), pinion-assist (P-EPS), and rack-assist (R-EPS). C-EPS systems place the motor on the steering column, P-EPS systems place the motor on the steering pinion, and R-EPS systems place the motor on the steering rack. Each type of system has its own advantages and disadvantages, such as weight distribution, packaging space, steering feel, and cost. Some newer types of EPS systems are also emerging, such as belt-drive (B-EPS) and dual-pinion (DP-EPS) systems, which offer more flexibility and scalability for different vehicle models and segments.

4 Motor trends and innovations

EPS motors are constantly evolving to meet the challenges and opportunities of the automotive industry and consumer expectations. Currently, EPS motors are becoming more compact, lightweight, and powerful, leading to improved fuel economy, performance, and handling, as well as reduced emissions and noise. Factors contributing to this trend include advanced materials, such as rare-earth magnets and high-strength steel; motor geometry optimization; winding and cooling optimization; and control techniques like sensorless control, predictive control, and artificial intelligence. Additionally, EPS motors are becoming more integrated with other vehicle components and systems, such as the steering column or electric powertrain, enhancing functionality and safety while reducing complexity and cost. Further, EPS motors are becoming increasingly customizable to driver preferences and needs in order to improve comfort and convenience. Examples of this trend include variable assistance levels, steering modes, feedback settings, haptic feedback such as vibration or sound, and learning/adaptation of driver behavior.

5 Here’s what else to consider

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