LEM has announced the launch of its new Single Monitoring Unit (SMU) sensor family, designed to enhance the performance of Full Hybrid Electric Vehicles (FHEVs), Plug-in Hybrid Electric Vehicles (PHEVs), and Battery Electric Vehicles (BEVs).
The modular SMU family aims to meet the needs of automotive battery management system (BMS) designers seeking to maximize the driving range of electric vehicles. The SMU continuously monitors vehicle parameters such as battery performance and safety systems, identifies anomalies, and supports diagnostics to improve vehicle efficiency and ensure regulatory compliance.
The design of the high-performance sensor addresses the need for minimal component size, allowing EVs to weigh less and travel further on a single charge. The compact SMU measures 29.1mm (H) x 35.5mm (W) x 49.9mm (L), with a busbar thickness compatible with 2mm to 3mm. The integrated busbar not only reduces size and improves accuracy but is also designed to accommodate various busbar dimensions.
The SMU uses Hall effect technology in an open-loop configuration, incorporating the latest LEM9 Application-Specific Integrated Circuit (ASIC). This ASIC, designed by LEM, adds intelligence at the Battery Disconnect Unit (BDU) level, enabling the measurement of environmental factors while ensuring accurate sensor performance.
Key features of the SMU include:
+ Improved accuracy through software algorithms that correct or adjust measurement data for mechanical stress-induced distortions or errors.
+ Achieving 1% accuracy up to 1300A and <1.7% up to 1500A, ideal for BMS applications.
+ Digital calibration providing end-to-end (E2E) protection and improved offset/sensitivity calibration.
+ Diagnostic warnings for under- or over-voltage.
+ A dedicated safe state mode to prevent malfunction due to sensitivity and offset drift, temperature measurement errors, or memory errors (RAM, FLASH, EEPROM, ROM).
+ An internal microcontroller with a built-in algorithm to correct magnetic offset, ensuring accurate and reliable sensor readings.
+ High isolation levels to withstand voltage differences greater than 800 V, enhancing safety and preventing electrical interference or damage.
The company reports that the new SMU family is compliant with functional safety conditions, meeting the stringent Automotive Safety Integrity Level (ASIL) requirements of the ISO 26262 standard for functional safety in vehicles. The first version to enter the market is ASIL B ready, with the potential to extend to ASIL C. ASIL B applies to systems with moderate safety risks, balancing safety with practicality in automotive design. The SMU family incorporates all necessary safety mechanisms and design processes to address risks associated with safety-critical automotive applications.
Source
