LEM releases a first-of-its-kind high-voltage battery sensor that combines shunt and Hall effect technologies

Novel Hybrid Supervising Unit optimises EV battery management systems at low cost

For the first time on the market, LEM has put together shunt and open-loop Hall effect technologies in a single part, called Hybrid Supervising Unit (HSU), to meet the challenges of small footprint, low cost and highest safety level in EV battery management systems.

The EV’s high-voltage BMS plays three key roles: it manages the battery’s state of charge and state of health, keeps the system and end user safe, and performs cell balancing as part of the battery optimisation process. For higher safety levels, system engineers typically use two separate devices, a shunt to measure 2000A and a current sensor fully isolated for measurements to 2000A.

Now LEM has combined the capabilities and performance of both technologies into a single unit, integrating it into the BDU. The signals from each section – the shunt and the current sensor – are then collected by the BMS.

At BDU level, the HSU allows:

· Minimal footprint, weight and cost (BOM).

· Minimised integration effort for faster time to market; and

· Easy system upgrade, without impacting the mechanical layout while improving safety.

At the BMS level, the HSU enables system developers to easily reach the ASIL D safety level required for EVs.

The shunt’s resistance is very low at 25µΩ, and the Hall part is galvanically isolated, with accuracy of 2% at 500A and 5% at 2000A. Signal communication lines are separated (shunt signal and analogue or digital bus for the Hall part), and there’s NTC (Negative Temperature Compensation) signal for shunt temperature compensation.

The current measuring range is up to ±2000A at 10s for both parts, as is the wide operating temperature range of −40°C to +125°C.

The HSU is the only component on the market with two technologies fitted into a standard shunt footprint (84 x 36 x 3mm). It is a plug-and-play unit, allowing easy mounting. LEM will initially offer the HSU00 part, with HSU01 to follow in June this year. The two are suitable for the two most common BDU busbar sizes: 84 x 36 x 3mm (HSU00) and 84 x 20 x 3mm (HSU01).

LEM plans to expand its HSU lineup, by introducing new technologies, for example combining a shunt with a coreless Hall-effect part. The goal is to continue to shrink the devices’ size and cost yet improve their performance.

CDT family for best-in-class Residual Current Monitoring.

It has been designed to achieve best in class performances, measuring and detecting as low as 5 mA DC or AC leakage.

Sensor family is suitable for various AC charging applications:

• AC wallbox
• ICCPD (charging cable)
• None isolated On Board Charger (OBC)
• V2G: Vehicle to Grid
• V2L: Vehicle to Load

The CDT sensor family give you the choice of having single or three-phase versions as well as safety version in the same housing and provide fast digital tripping output when leakage current is detected.

LEM reinforces its leadership in the high-precision segment with two new products, completing its IN family of current sensors

LEM continues to improve and innovate its existing IN product family of current sensors, and adds two new members to its IN family of current sensors.

The IN 1500-S current sensor is specifically designed for high performance and precision in 1500A nominal current applications, while the IN 1000-SHF current sensor is suitable for applications requiring very wide bandwidth. The new products are the latest additions to the highly successful IN family of high-precision sensors, known for their high reliability in applications such as MRI, calibration units, power meters, and energy measurement.

With IN 1500-S, the IN family for current sensing now boasts eight devices, and it is LEM’s most advanced high-precision range of current sensors yet, underpinned by LEM’s closed-loop current transducers that use a highly-accurate zero-flux detectors based on LEM’s fluxgate technology. The current sensors achieve ultra-high precision current measurements for DC, AC and pulsed currents.

Using fluxgate technology in transducers for precise current measurement is not new; however, it has limitations linked to a ripple that stems from the excitation voltage. LEM’s innovation takes fluxgate current transducers to previously unachieved performance levels through digital technology, gaining not only a major reduction of the ripple from the fluxgate driving signal but significantly improving the device’s immunity to temperature effects, interference and supply voltage variation. In addition, LEM has used FPGAs for faster start-up, and the devices are also UL/UR certified for the Americas.

The IN family already boasts the IN 100-S, IN 200-S, IN 400-S, IN 500-S, IN 1000-S, IN 1200-S and IN 2000-S devices, for nominal currents of 100A, 200A, 400A, 500A, 1000A, 1200A and 2000A, respectively. Part IN 1500-S for 1500A now completes the lineup. All of them have a D-Sub 9-pin male interface connector, and large apertures for various sizes of cables and busbars. Their metal housing improves immunity to external interference and improves power dissipation. A status signal indicates the transducer’s state and an LED indicator confirms normal operation.

Their other main characteristics, including that of the new IN 1500-S device, are:

• Best-in-class accuracy, with excellent linearity (to ±0.0002%) and minimum electrical offset;
• Broad frequency bandwidth: up to 2MHz @ ±3dB;
• Overcurrent and protection embedded in the design;
• Extended operating temperature range, between -40°C and +85°C, except IN 1500-S which operates between -40°C and +50°C;
• Extremely high stability: up to 0.1ppm/month.

The second device LEM is launching now is the IN 1000-SHF, bringing a breakthrough in current measurement. IN 1000-SHF pushes the bandwidth to 2.5MHz (at ±3dB), with a delay time of just under 1ns (at 10% of nominal current) – that’s a thousand times quicker than the IN 1000-S model and over five times the bandwidth. Electrical offset is improved by a factor of two, to ±5ppm at +25°C, temperature drift by a factor of three, to ±0.1ppm/K over its full operating temperature range, and the peak-to-peak noise level is under 0.218ppm – more than 82 times better than the standard IN 1000-S model. Current output is 1A at Ip = 1000A.

Its operating temperature range is -40°C to +85°C, and like with the IN 1500-S, an external LED shows its normal operation and there’s an additional output to show the state of the transducer. It is offered in a compact package, suitable for flat or vertical panel mounting.

With these characteristics, and its extreme accuracy, this makes in IN 1000-SHF a unique offering on the market.

All LEM IN devices are suitable for a wide range of industrial, laboratory and medical applications, which require high-precision sensors, including:

• Feedback elements in high-performance gradient amplifiers for MRI;
• Feedback elements in high-precision, high-stability power supplies, in power analysers and oscilloscopes;
• Calibration units;
• Energy measurement;
• Feedback element for power meters (e.g. EV test benches) and T&M equipment; and
• Medical equipment like various scanners.

The first Integrated Current Sensor with Sigma Delta Bitstream output

• Replaces shunt and digital isolator for reduced cost and footprint
• Produces Sigma Delta bitstream for clean easy to use signal
• Offers efficient performance for servo drives, robotics and other high precision applications

Main Features

• Sigma Digital bitstream output with 10 MHz clock in or out
• High resolution with an effective number of bits (ENOB) 11 to 13 bits
• Different output modes: Single ended CMOS, Differential RS422, LVDS
• Fast internal OCD of 2 µs

FRS and FL, the first eco-friendly current sensors for the renewable energy industry

Based on Open Loop Coreless Integral (OLCI) technology

• Measure DC currents from 2 kA up to 42 kA without surge current limitations
• Fast response time, 1 MHz bandwidth
• 80% less weight
• 85% less energy consumption
• 100% recyclable/recoverable material at end of life

FRS

• Measures 1,000 to 3,000 A
• Supports primary busbar aperture of 104 x 22 mm

Capable of measuring high DC currents from 2kA up to 42kA without surge current limitations, the Open Loop Coreless Integral (OLCI) sensors feature a large aperture for accurate measuring of high currents on large busbars, with up to 1MHz bandwidth for high frequency applications. They are also significantly lighter (80%) and more cost effective than open loop or closed loop current transducers operating within the same current measuring range.