Multiaxial Coreless Current Sensor for Electric Vehicle Inverters

The development addresses precision and packaging constraints in hybrid and electric vehicle (HEV/EV) powertrains. The integrated component provides a multiaxial coreless sensing approach designed specifically for high-voltage traction inverter motor control.

Multiaxial Sensing Architecture and Mechanical Displacement Tolerance
Traditional current monitoring in electric powertrains presents an architectural compromise. Core-based implementations, such as ferromagnetic C-cores, maintain high precision and noise immunity but add significant mass and physical volume to the inverter module. Conventional single-axis coreless alternatives reduce system weight but exhibit susceptibility to displacement errors caused by operational mechanical vibration and magnetic crosstalk.

The dual-axis architecture measures magnetic flux densities along both the horizontal and vertical axes simultaneously. Integrated algorithmic processing resolves positional shifts, delivering up to a twentyfold improvement in measurement accuracy compared to single-axis implementations. Under mechanical displacement conditions, the device maintains a measurement error of less than 1% at 0.4 mm of relative movement and achieves 0.25% error at 0.1 mm.

Inverter Efficiency and Busbar Integration
In 800V powertrain architectures, torque control precision directly determines motor phase efficiency and drive dynamics. Tight current measurement reduces torque ripple, minimizing acoustic noise and thermal energy loss while refining control loops across varying load conditions.

Furthermore, differential coreless implementations typically demand mechanical busbar modifications—such as slots, notches, or perforations—to generate measurable differential magnetic fields. These geometric alterations disrupt current distribution and degrade thermal dissipation across high-current paths. The multiaxial sensor monitors direct magnetic fields over unmodified, solid busbars, simplifying mechanical design, streamlining thermal management, and maximizing board space within the inverter housing.

Additional Context: Technical Specifications and Competitive Benchmarking
Conventional coreless current sensing in automotive drivetrains relies on differential Hall elements (such as Allegro MicroSystems ACS37002 or Melexis MLX91220 series) or external flux concentrators. Standard differential sensors reject uniform stray fields but remain sensitive to orthogonal cross-axis displacement and z-axis positional variations relative to the busbar. In contrast, multiaxial sensing decouples spatial movement from magnetic field amplitude using vector components (B_x, B_z), allowing direct calculation of true current without requiring localized magnetic field alteration. This technical approach preserves busbar continuous ampacity ratings while matching the coreless footprint scale.

Edited by Evgeny Churilov, Induportals Media - Adapted by AI.

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