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Inductive rotor position sensor with four inductive coils

**Library:**Simscape / Electrical / Sensors & Transducers

The Inductive Rotor Position Sensor block uses the theory of eddy current losses to obtain the rotor position. It consists of four planar coils and a target trace that detect the rotor position. The target trace is shaped in a sinusoidal way and made from conductive material. The distance between the four planar coils is equivalent to 90 degrees of one cycle.

The voltages between the elements of the sensor are described by the equations:

$${v}_{x}={V}_{x0}+{A}_{x}\mathrm{cos}(N\theta )+K\mathrm{sin}(\theta )$$

$${v}_{y}={V}_{y0}+{A}_{y}\mathrm{cos}(N\theta -\frac{\pi}{2}+\beta )+K\mathrm{sin}(\theta )$$

where:

*v*is the cosine voltage._{x}*v*is the sine voltage._{y}*A*and_{x}*A*are the voltage amplitudes for the_{y}*x*and*y*axes that reflect the sensitivity mismatch.*V*and_{x0}*V*are the voltage offsets for the_{y0}*x*and*y*axes.*N*is the number of pole pairs.*θ*is the mechanical position.*β*is the quadrature error.*K*is the tumbling factor.

The block uses this equation to decode the angle:

$${\theta}_{out}=\mathrm{arctan}\left(\frac{{v}_{y}}{{v}_{x}}\right).$$

This figure shows the effects of the tumbling factor:

Use the **Variables** settings to specify the priority and initial target
values for the block variables before simulation. For more information, see Set Priority and Initial Target for Block Variables.