Automotive supplier Continental has developed an innovative sensor technology that directly measures the temperature inside the rotor of permanently excited synchronous motors (PSM), aiming to enhance electric motor performance, reduce costs, and improve sustainability.
The new electric motor rotor temperature sensor (eRTS) achieves a temperature measurement accuracy with a tolerance of just three degrees Celsius, a significant improvement over the 15-degree margin of error typical of existing software-based temperature simulations, Continental said. The sensor consists of two parts: a small unit called the ‘Mote’ embedded near the rotor magnets and an external ‘Transducer’ that transmits data to the inverter controller.
More precise temperature data from the rotor enables automakers to optimize the use of rare earth materials, which are critical for heat-resistant magnets but costly and environmentally sensitive to source. Accurate rotor temperatures allow for more targeted cooling system control and precise dosing of rare earths during motor development, potentially boosting motor power without compromising durability.
“Permanent magnets in rotors can reach temperatures up to 150 degrees Celsius under full load, risking demagnetization and loss of function if overheated,” Continental explained. Previously, temperatures were estimated indirectly using stator sensors and environmental variables, but the new sensor provides direct, real-time measurements.
Bin Huo, Head of Continental’s Passive Safety and Sensorics division, said, “With less resource consumption and lower costs, eRTS sensor technology is advantageous to current solutions. This innovation confirms the value of focused investment in our product center, and we plan to expand our EV sensor portfolio further.”
Christoph Busch, Head of the E-Mobility Sensors Product Centre, highlighted the sustainability impact: “Reducing rare earth use contributes to a more sustainable supply chain as electric vehicle adoption accelerates. Combined with other sensor technologies like the e-Motor Rotor Position Sensor, eRTS can form a system solution that delivers cost and effort savings for manufacturers.”
Continental’s breakthrough underscores the increasing importance of precise sensor technologies in advancing electric vehicle efficiency and supporting the industry’s sustainability goals.