Automotive Current Sensors: Applications & Products
LEM is a key player in the new generation of automobiles, using its know-how acquired over 40 years to develop the specific technologies to measure battery and motor-phase currents that allow the car industry to meet the ever-increasing requirements in energy efficiency. The following pages give you an introduction into LEM’s technology for automotive applications.
Automotive Battery Management
LEM works with all the major car manufacturers and Tier-1 suppliers in the world and supplies galvanically-isolated electronic transducers that measure electrical parameters in battery-management and motor-control applications.
Main applications for Automotive Battery Management
LEM Automotive is specialized in developing and manufacturing current transducers for battery management and motor drive applications in cars, buses and trucks. By controlling the current in energy-intensive applications, LEM participates in the global effort to reduce overall energy consumption.
Typical applications for automotive transducers include:
Conventional battery management
Car makers have been focusing their attention on reducing fuel consumption for several years. Currently, the main focus is to reduce fuel usage by managing the charging of the main battery. Early progress in energy management has now shifted focus and is heavily concerned with power management. This includes managing the battery, the combination of additional functions of the battery’s state of health and safety features, such as auto-disconnect. Secondary functions have been reduced and the size of the alternator has been optimized thus instantly reducing global electrical consumption.
Hall-effect sensors ( HAB, HABT, HAG, HAH1) and Smart Shunt (SSVT) are the product of choice for this application.
Generator current monitoring
The need for higher energy in cars is increasing. Generators are required to provide more current to the vehicle loads and batteries, yet to be more efficient, the current needs to be controlled. The HAB and HAG current sensor families are best suited to provide the BMS (Battery Monitoring System) with the proper current information. Depending on the size of the car, this current can flow from 60A (conventional car) up to 240A (service cars and trucks).
Battery management for hybrid and EV markets
The production of electric car and hybrid vehicles is increasing. Both types of vehicle need high current capability batteries to run the 50kW or more motors and these use high voltage systems. The current sensors for these batteries need to be isolated.
Flux Gate Sensors (CAB, CAB-SF) and Hall-effect sensors (HAH1, HSN, HST, DHAB) are the product of choice for this application.
Automotive Motor Control
LEM Automotive is specialized in developing and manufacturing electronics transducers that measure electrical parameters in battery-management, motor-control applications, DC/DC converters and on-board chargers. LEM Automotive works with all the major car, bus, trucks manufacturers and Tier-1 suppliers in the world.
Main Applications for Motor Control and Energy Converter
By controlling the current in energy-intensive applications, LEM participates in the global effort to reduce overall energy consumption.
Typical Applications for Automotive Transducers include:
Applications of Auto Motor Control
Electric and hybrid vehicle motor converter
Production of electric and hybrid vehicles is increasing. Both have power motors (50kW or more) and use 3 to 6 phase inverters to drive the traction and generator motors precisely and reliably. The trend is to opt for high frequency and smooth wave forms, which is fuelling demand for fast current sensors. There are two distinct market needs:
For standard products such as HC5/HC6, HAH1, HAH3 family and HCx family.
For a full custom solution which fits with the mechatronic approach (HAH3, HAH2 dedicated shape)
If you would like further information regarding electric hybrid vehicle motor converters, please do not hesitate to contact our technical staff, who will be happy to advise you about LEM’s standard and custom solutions in this field.
Other motor inverters
There is a huge volume of various motors that require current sensing. Typical applications include power steering, brake by wire, active suspension and electric compressors with currents that can vary from 20A up to 200A. LEM provides a whole range of products to cover these applications within the HC2 family. We are currently working on innovative standard and custom solutions that are due to be launched in the coming months.
DC/DC power converters
Environmentally friendly cars and trucks require different levels of voltage; most loads run under 12V or 24V while the traction motors need a much higher voltage. There is a need to build efficient step-up and step-down converters in the car to make these different voltages available. The tendency is to have high frequency resonant converters which need fast current transducers.
The HC5, HC6 and HAH1DRW or HAM (high frequency bandwidth up to 300kHz) families can handle the speed needed to meet these requirements.
One of the biggest challenges of the 21st century will be to decarbonized the traditional transportation accountable for over 25% of global CO2 emissions. Decarbonization must be done without sacrificing the interconnectedness we’ve come to expect from modernity. With a fleet of 157 mil of EVs expected in 2030, the charging infrastructure needs to proceed in parallel, and sometimes anticipate that of the EV stock. LEM actively contributes to the deployment of electric vehicle charging stations, by supplying very high technology sensors and meters making the charging stations more reliable, safer, more affordable, and smarter.
Current Sensors for Power Module
Current control loop for Power modules
LEM provides a wide range of current sensors for power module converters, transforming the Alternative Current to a Direct Current. Power converters are placed in stacks to increase the power of DC fast charging stations, up to 400kW. In average eight converters are present. In each power module, current sensors are necessary to ensure the control loop function which regulate the stability and the power of inverters.
DC Meter for EV Chargers
The new DC Billing Meter (DCBM) from LEM is a smart and compact billing solution that will help electric vehicle charging stations take advantage of the benefits of DC charging. Offering a power measurement range from 25kW to 600kW, the DCBM is a legal and certified meter that provides accurate billing of DC chargers.
To reduce this charging time to only a few minutes, charger manufacturers convert the AC into a direct current (DC) outside the car, bypassing the On-Board-Charger (OBC) and supplying the battery pack of the electric vehicle directly. This method can boost charging power up to 400 kilowatts. However, this conversion stage generates power losses, which do not have to be paid for by the end user, the EV’s owner. Thus, an electric meter is placed after the conversion stage to monitor and bill the exact energy transferred to the electric vehicle.
LEM products meet all quality requirements for the automotive industry and comply with RoHS specifications. All our production and development centers are certified with ISO TS-16949 (in Switzerland and in China). Based on our deep knowledge of applications and current measurement technologies, LEM develops both catalog and customized products which can be perfectly tailored to meet your needs in terms of performance, space requirement and cost.