German automotive supplier Continental has introduced a revolutionary sensor technology designed to measure temperature directly on the rotor of permanently excited synchronous motors (PMSMs)—a first in the electric vehicle (EV) industry. The innovation, known as the e-Motor Rotor Temperature Sensor (eRTS), is poised to make electric motors more powerful, cost-effective, and environmentally sustainable.
This advancement marks a significant leap forward in EV motor technology. Unlike current systems that estimate rotor temperature through indirect methods like stator sensors, current flow, and environmental data, the eRTS provides direct, real-time temperature readings on the rotor itself. This dramatically reduces the tolerance range from 15°C (59°F) to just 3°C (37.4°F), allowing for far greater accuracy and efficiency in motor design and operation.
Continental emphasizes that this precision unlocks new possibilities for resource optimization, particularly in the use of rare earth elements. These materials are traditionally added in greater amounts to boost the heat resistance of magnets, compensating for the wide error margin in conventional temperature monitoring. With the eRTS, manufacturers can reduce reliance on rare earths, cutting material costs and contributing to a more sustainable supply chain—a critical step as EV production scales globally.
“With less resource consumption and lower costs, eRTS sensor technology is advantageous to current solutions,” said Bin Huo, head of Continental Automotive’s Passive Safety and Sensorics segment. “This innovation shows that investing resources and focusing expertise in our product center were the right decision. We will continue to successively expand our EV sensor portfolio.”
PMSMs are a staple in electric vehicles due to their high efficiency, strong torque at low speeds, and quiet, smooth operation. However, their rotors can reach temperatures of up to 150°C (302°F), making accurate temperature control critical to avoid magnet demagnetization. Until now, manufacturers had to err on the side of caution, overcompensating with expensive materials to handle potential overheating.
By narrowing the tolerance range, the eRTS allows engineers to push motor performance boundaries more confidently. It also enables more innovative and optimized motor designs, helping reduce EV production costs while enhancing power output and longevity.
Christoph Busch, head of Continental’s E-Mobility Sensors product center, noted that this new sensor aligns with the company’s goal of improving efficiency and sustainability in EVs. He highlighted that eRTS not only reduces material consumption but can also be integrated with other Continental innovations, like the e-Motor Rotor Position Sensor, to create a complete system solution. This combined approach offers cost-saving synergies and greater design flexibility for EV manufacturers.
As the number of EVs on the road continues to grow, innovations like eRTS represent a critical step toward scaling electric mobility responsibly, improving both performance and sustainability in future vehicle platforms.
By Impact Lab
