Power Electronics Europe Issue 4 - November 2022

24 AUTOMOTIVE CURRENT SENSORS www.lem.com Issue 4 2022 Power Electronics Europe www.power-mag.com measurement over the widest range of applications. The sensors are part of the company’s portfolio that are designed specifically for use with EV traction inverters. This allows customers to select highly reliable off-the-shelf products for their inverter requirements which enables EV component manufacturers to achieve a rapid time-to-market turnaround. When looking at solving customers’ problems that existing current sensors could not tackle, the R&D department at LEM came up with a solution in the form of the HSTDR single-phase current sensor with integrated busbar, that is considerably smaller than any traditional current sensor with an opening hole. Designed for DC- Link voltage measurement and 3-phase current measurement, but also for DC/DC converters, the HSTDR’s small footprint offers a greater flexibility to designers working within the constrained space availability of a traction inverter box. The HSTDR also offers protection against external fields and high SNR thanks to its magnetic core with a small air gap (Figures 1 and 2). Busbars tend to be isolated from the magnetic core in traditional designs but LEM’s approach of having the core located directly on the busbar, which has a restriction, means the core can be much more compact. Typical current sensors with an opening hole tend to require a large aperture for sliding on to busbars that can be of a complicated design (resulting in a large sensor), whereas there are no limitations on where to fit sensors with integrated busbars. This makes it possible to minimize the aperture of the magnetic core – and therefore reduce the overall size of the core by up to 40 % – while increasing the current measuring range by 60 % compared to the previous generation HSNDR. This again offers superior flexibility to EV component designers because the sensor is capable of being Figure 1: HSTDR single-phase current sensor with integrated busbar Figure 2: HSTDR single-phase current sensor for 1500 A that incorporates core, busbar and sensing element in a single package Figure 3: HSTDR 1000 A single-phase current sensor