Magnetic position sensors accurate for high speed rotors - Embedded.com

Magnetic position sensors accurate for high speed rotors

A new series of magnetic position sensors from ams feature extremely accurate angle measurements of rotors spinning at high speed. The new “47 series” position sensors include the AS5047D , AS5147 and AS5247 with DAEC (Dynamic Angle Error Compensation), a technology developed by ams that eliminates the measurement error attributable to propagation delay.

  • The AS5047D is targeted for industrial applications including robots and encoder modules.
  • The AS5147 is an AEC-Q100 qualified part for automotive applications such as electronic power steering and pumps.
  • The dual-die AS5247 (also AEC-Q100 qualified) is designed for automotive applications requiring  the highest level of functional safety compliance. 

All three parts are specified with a maximum ±0.17° angle error (excluding integral non-linearity). This precision measurement performance is the result of implementing DAEC, an algorithm which performs error compensation internally and responds automatically to changes in the speed of rotation.

In high-speed brushless DC (BLDC) motors and permanent magnet synchronous motors (PMSM) the sensor’s high accuracy enables better execution of the commutation scheme, resulting in higher torque and efficiency, lower torque ripple and smoother operation.

All three devices provide absolute position measurements as a digital PWM output, and UVW outputs for use in field-oriented commutation schemes. They also provide an incremental ABI output equivalent to the output of an optical encoder. This means  an AS5047D IC can replace an optical encoder without requiring the user to change the software interface in the host system’s microcontroller or DSP.

The 47 Series devices offer high 14-bit resolution (to 0.022°) in their digital SPI output, and maximum resolution of 2,000 steps per revolution in decimal mode and 2,048 steps per revolution in binary ABI mode.

The AS5047D, AS5147 and AS5247 will be displayed in the ams booth (stand 909) at the Sensors Expo, Chicago, 24-26 June 2014.

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