Companies co-design new current sensor for high-power automotive applications

LEM states that the transition to a decarbonised economy is accelerating fast, and the demand for innovative technologies is growing to support the large-scale adoption of EVs. The lightweight and compact design of power electronic components is key to facilitating efficient design and increasing the driving range of EVs – adding value to Tier 1 supplier/OEM system engineers and consumers.

After working closely together for several years, LEM and Semikron Danfoss have designed a new concept called Nano that merges the capabilities of LEM’s range of current sensors with Semikron Danfoss’s DCM half-bridge power module platform for high-power automotive applications. The collaboration produces a core-based sensor that is 60% smaller than anything previously available without compromising performance.

“The Nano current sensor is a great example of how LEM is able to work hand-in-hand with industry specialists to tackle customers’ system challenges and create innovative current sensing solutions that deliver optimal performance levels. This project was a significant challenge, and the beauty of its success lies in the perfect collaboration with Semikron Danfoss. Both teams have been able to work almost like one single team. We have been able to push the boundaries because we created a synergy from our different expertise.” says Damien Coutellier, senior electronics engineer and Nano project manager at LEM.

The newly developed sensor makes integrating the sensing function into the power module completely feasible, minimising component footprint, simplifying assembly, and keeping costs down. It is ideal for EV traction inverters with the DCM platform and compatible with other Semikron Danfoss power module platforms. The innovative idea behind the Nano concept was to design a core-based current sensor that could fit into the unused space between the top side of the power module and the gate driver board.

This allows the footprint of the current sensor to overlap with the footprint of the power module. As a result, the Nano current sensor only takes up additional space in the inverter. Also, no further components are needed to fixate the sensor mechanically and connect it electrically to the driver board. This delivers the highest level of integration that a core-based current sensor can achieve. The Nano current sensor is mounted on the DCMTM power module, which uses the latest generation of 750V and 1200V SiC MOSFETs and has a rated current of 200A to 1000A.

Characteristics of the DCM platform signify that the new device satisfies insulation coordination necessities for 800V batteries per IEC 60664-1. At the same time, superior mechanical robustness, high-temperature stability and protection from humidity and vibrations allow inverters to deliver stable and reliable performance in various environments.

“By working hand-in-hand with LEM, Semikron Danfoss was able to develop a unique solution that combined the best of both worlds – our expertise in power electronics with LEM’s current sensing and metrology knowledge. As a result, this plug-and-play solution will save our customers a great deal of time and effort because they will no longer have to worry about the current sensor footprint, assembly, validation, testing or even performance – they are all taken care of in a single package,” says Thomas Zöls, senior electrical engineers at Semikron Danfoss.