Hall-effect position sensor family for high-speed e-motor applications

TDK Corporation has introduced the Micronas fast 2D Hall-effect position sensor family HAL 302x, meeting the demand for stray-field robust motor position sensing and ISO 26262-compliant developments in automotive and industrial applications. This new sensor family initially comprises two members, HAL 3020 and HAL 3021, and provides differential and single-ended sine and cosine analog outputs for standard angle calculation by an external microcontroller/ECU. HAL 3020 is the correct choice for cost-effective applications such as electric pumps or electric valves. For those types of applications, the sensor can readily be combined with the company’s Micronas embedded motor controller portfolio for precise and safe motor control. HAL 3021 is ideal for demanding high-speed sensing applications such as electric power steering, e-motors (e-axle), electric brake boosters and electromechanical braking.

These sensors can measure a complete 360° rotational angle by evaluating vertical magnetic-field components (BZ). While HAL 3020 employs an array of three horizontal Hall plates, HAL 3021 employs six. These sensors can suppress external DC and AC magnetic stray fields (ISO 11452-8). By suppressing harmonic disturbances in the stimulation signals via device-internal calculations, a simple and cost-efficient two-pole ferrite magnet in an on-axis (end-of-shaft) configuration is enough to measure the absolute angular position. The requirement for expensive magnetic shielding and stronger target magnets is removed thanks to the inherent stray-field robustness. This gives more flexibility in designing and producing next-generation electric motors to be employed in HEV and EVs.

A key strength of HAL 3021 is that the device provides best-in-class robustness against static and dynamic mechanical misalignments, covering off-axis displacement, airgap variation and tilt. This provides highly reliable and efficient field-oriented control of motors over their lifetime. To lower the load of the ECU, the sensor may compensate on-chip for the main sensor- and system-level non-idealities, such as sine and cosine amplitude mismatch, offset errors, (absolute) 0-angle, and orthogonality errors.

The sensor is defined as SEooC ASIL C ready according to ISO 26262, supporting system-level integration up to ASIL D. The sensor combines multiple safety monitoring functions, which help to improve diagnostic coverage and ease the external safety supervision on the ECU side. It functions in the junction temperature range from –40C to +170C. The sensor is offered in the small eight-pin SOIC8 SMD package.

Main application areas include BLDC and PMSM commutation in a safety-relevant environment, electric brake booster, EMB, clutch and transmission actuators, electric pumps, and electric valves.

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