New Conti Sensor for Greater Efficiency in Electric Cars

The technology company Continental is expanding its sensor portfolio for the rapidly growing electric mobility market with the introduction of a new sensor. The inductive high-speed e-motor rotational position sensor (eRPS) captures the precise position of the rotor in an electric synchronous motor. This aims to increase efficiency and enable smoother operation.

Standard solution for almost all electric cars

Existing solutions for rotational measurement often rely on the resolver principle (a rotating electrical transformer), a complicated system that must be specially adapted for each type of synchronous motor. The eRPS, on the other hand, is a standardized component that is suitable for any motor regardless of the number of pole pairs. This new sensor can be easily transferred from one motor to another, making it an attractive option for electric vehicles. Compared to existing resolver sensors, the eRPS is more compact, 40 percent lighter, and significantly more robust. Production is scheduled to start at the end of 2025.

“The increasing electrification of vehicles is leading to more synchronous motors. This ranges from large and powerful motors such as traction motors to smaller ones like electric pumps. Our standardized eRPS technology offers a wide range of applications in electric vehicles,” said Laurent Fabre, head of the Passive Safety and Sensorics segment at Continental. “Measurement accuracy, compact dimensions, and the all-in-one sensor concept, which combines several functions, contribute to a high degree of integration in the vehicle.”

Small Sensor for More Compact Motors

The eRPS was specifically developed for the control of synchronous motors, where the rotor rotates at the same speed as the rotating field in the machine. To achieve maximum efficiency of the motor, the motor control must know the exact position of the rotor, which makes this sensor design an essential component of synchronous motor applications. While the resolver is a comparatively massive sensor, the eRPS is very flat and supports compact motor designs with a short length. The sensor design is based on the eddy current principle and is optimized to increase robustness with respect to mechanical tolerances. Advanced integrated circuits are used for signal processing.

Redundancy for Maximum Safety

These were developed in accordance with ISO 26262 for functional safety in the automotive industry to achieve ASIL C. Optionally, two integrated circuits can be embedded in the eRPS to ensure redundancy, which is an essential component of the overall system's functional safety.

Development based on the Conti Brake-by-Wire concept

Although the traction motor of an electric or hybrid vehicle is a prominent application case, there are other synchronous motors in electrified vehicles. For example, dry braking systems are also electrically actuated and require position sensors. In the development of the eRPS, Continental drew on existing knowledge and experience with inductive measurement methods. For instance, the Brake-by-Wire brake system MK C2 uses an inductive motor position sensor and was the basis for the development of sensor concepts with increased speed and accuracy, as is the case with the eRPS.