Fiber optic sensors are better suited than traditional thermocouples for temperature sensing in electric vehicles. Thermocouples are too slow, susceptible to electrical and magnetic interference, and cannot withstand the higher voltages used in electric vehicles. Fiber optic sensors can accurately measure temperature at voltages over 1000V and currents over 700A used in electric vehicles. They are also unaffected by electrical and magnetic fields, faster responding, and can be installed in small spaces. Fiber optic sensors allow for more accurate thermal profiling of electric vehicle components like motors, batteries, and power electronics during testing.

1. RM Fiber Optic Solutions for Emobility Segment

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RM Fiber Optic Solutions for Emobility Segment
Electric Cars Electric Vans Electric Trucks Electric Buses Electric Off-Road Veh Railways
Aeroplanes Drones Electric Boats Electric Ships Charging Stations Charging Centers
Emobility

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 Electric vehicles are going to 1000V+, 700A+ for cars and 2400V+, 1000A+ for trucks
 Traditional thermocouples are too slow and significant limitation above 200V
 Thermocouple output is in millivolts and gets affected by Electric and Magnetic fields
 Safety Risk from Thermocouples: Risk of short circuit at higher voltages, Corrosion etc.
 Thermocouples are Non-Linear: Sensors are non-linear, require complex compensation
 Thermocouples are large: not suitable to fit into tiny spaces on PCBs, Power Electronics, Charging Points
 Slower Response: Thermocouples are not fast enough for accurate thermal profiling
 Variation from Batch to Batch: Impact accuracy and repeatability of testing
 Susceptible to High Voltage and Magnetic Fields
 Thermocouples are not suitable for Explosive Environments
 Thermocouples are not suitable with longer signal cables
Why Fiber Optics Now?

4. E-Mobility Applications
Battery Simulation Battery Test Stands Motor Testing Power Train Testing
Power Electronics Li-ion Battery packs Power Cables Fast Chargers
Sensing Solutions for:
Leading Temperature, Pressure, Vibration, Partial discharge sensing solutions for E-Mobility
segments that are undergoing major design transformations with EV’s.
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Emobility Components Tested with Fiber Optic Sensors
Battery and BMS
EV Motors
Power Electronics
HV Cables,
Terminations and
Joints
Charging Plug

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Fiber Optic Temperature Solutions: EV Motors
Permanent Magnet Synchronous
Motors (PMSM)
Induction Motors Switched Reluctance MotorsDC Motors
Series and Brushless
Series Motors (PMDC)
Brushless DC (BLDC)
Radial Flux PMSM Squirrel Cage
Slip Ring
SRM-Motor
SRM - MotorAxial Flux PSMS
• Solution for all kinds of EV Motors and Drivetrains

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Fiber Optic Temperature Solutions: EV Motors
Why Temperature Testing and Monitoring in EV
Motors?
1. ~30%-40% of all failures in Induction Motors are related
to Winding Insulation Breakdown
2. High Temperature is mainly responsible for degradation
of Winding Insulation
• Winding Insulation Breakdown results into significant
thermal stress – Start of a Vicious Cycle
3. Higher Power Density of EV/HEV Motor drive systems
further increases the risk of Thermal Stress
4. EV/HEV Motors are susceptible to aging effects due to
high motor loads encountered in
• Harsh Environments: Steep Terrains, High Payload, High
Ambient Temperature
• Rapid accelerations and breaking
Effective Countermeasures in Practice
1. Design Optimization and Stress Testing at Product
Development Stage
• Accurate Motor Thermal Profiling
• Precise localization of weak points in insulation system
• Maximize Cooling System Efficiency
2. Identify the Performance Limits of Motor accurately
3. Accurate analytics for remaining design life and
identification of incipient failure conditions
4. Effective machine thermal control and Protection
5. Design Refinement / Optimization based on filed data