Hall-effect position sensors target e-motors

TDK Corp. has introduced the Micronas HAL 302x family of 2D Hall-effect position sensors for stray-field motor position sensing, delivering high angular accuracy performance in challenging mechanical and electrical conditions. They also address the need for ISO 26262 ASIL-C safety compliance in automotive and industrial applications.

The initial products released are the HAL 3020 and HAL 3021, featuring differential and single-ended sine and cosine analog outputs for standard angle calculation by an external microcontroller/ECU. The HAL 3020 targets cost-effective applications like electric pumps or electric valves. In these applications, the sensor can be combined with TDK’s Micronas embedded motor controller portfolio for more precise and safe motor control. The HAL 3021 suits more demanding high-speed sensing applications like electric power steering, e-motors (e-axle), electric brake booster and electromechanical braking (EMB).

Other applications include brushless DC and permanent-magnet synchronous motor commutation, clutch and transmission actuators and starter/generator systems.

The HAL 302x sensors can measure a full 360° rotational angle by evaluating vertical magnetic-field components (BZ), said TDK. The HAL 3020 uses an array of three horizontal Hall plates, while the HAL 3021 uses six. Both sensors suppress external DC and AC magnetic stray fields according to ISO 11452-8.

“By suppressing harmonic disturbances in the stimulation signals through device-internal calculations, a simple and cost-efficient two-pole ferrite magnet in an on-axis (end-of-shaft) configuration is sufficient to measure the absolute angular position,” said TDK.

As a result of the inherent stray-field robustness, it eliminates the need for magnetic shielding and the use of stronger target magnets, the company said. It also provides greater flexibility in the design and production of electric motors used in hybrid and electric vehicles.

The HAL 3021 is said to offer best-in-class robustness against static and dynamic mechanical misalignments, such as off-axis displacement, airgap variation and tilt to ensure reliable and efficient field-oriented control of motors over their lifetime. “To lower the load of the ECU, the sensor can compensate on-chip for the main sensor- and system-level non-idealities, like sine and cosine amplitude mismatch, offset errors, (absolute) 0-angle, and orthogonality errors,” said TDK.

The HAL 302x family is defined as Safety Element out of Context (SEooC) ASIL-C ready according to ISO 26262, supporting system level integration up to ASIL D. The sensor integrates a variety of safety monitoring functions to increase diagnostic coverage and simplify the external safety supervision on the ECU side. It operates over the junction temperature range from –40°C to 170°C.

Other features include a wide customer programmable magnetic-field range between 5 and 250 mT to adjust for different mechanical requirements and magnetic fields, a voltage range from 3 V to 5.5 V, overvoltage and reverse voltage protection, and a fast response and high output bandwidth for applications up to 150,000 rpm.

Samples of the HAL 3020 and HAL 3021 are available now. They are packaged in an eight-pin SOIC8 SMD package. Volume production is planned for the first half of 2024.