Continental has developed a new sensor technology that directly measures the temperature inside permanently excited synchronous motors in electric vehicles (EVs), marking the first time this data is captured on the rotor itself.
The eRTS sensor technology offers a precise alternative to algorithm-based temperature projection in permanent magnet synchronous EV motors.
The e-Motor Rotor Temperature Sensor (eRTS) improves measurement precision by reducing the tolerance range from 15° C (typical for software-based estimation) to just 3° C.
This enables manufacturers to optimize motor performance and reduce the use of rare-earth elements, which are typically added to enhance thermal stability.
The eRTS is part of a broader portfolio from Continental’s E-Mobility Sensors (EMS) product center, focused on supporting thermal, current, and torque sensing technologies for EV systems.
Addressing heat and rare-earth dependency
EV rotors operate under demanding thermal conditions, often reaching up to 150° C. Conventional systems estimate rotor temperature indirectly, using stator measurements, current data, and ambient conditions.
To account for wide tolerance bands, manufacturers rely on rare-earth materials to protect magnets against demagnetization at higher temperatures.
By enabling more accurate measurements, the eRTS helps narrow the required tolerance range. This may reduce the amount of rare earths needed and also opens opportunities to improve motor efficiency by safely pushing performance boundaries.
Technical architecture
The eRTS consists of two components:
- Mote element: A wireless sensor mounted near the magnet inside the rotor
- Transducer element: Located externally on the chassis and wired to the ECU
The transducer powers the mote and receives its measurement data. Communication and power transfer between the components are achieved using Piezo-based ultrasound, eliminating the need for onboard rotor wiring or batteries.
This rotor-level temperature sensing system aims to enhance EV motor control strategies, enable more sustainable material use, and increase design flexibility for future electric drivetrains.
Filed Under: Technology News