Inductive Rotor Position Sensor

Inductive rotor position sensor with four inductive coils

Since R2020a

• 

Libraries:
Simscape / Electrical / Sensors & Transducers

Description

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.

Equations

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

$$v_x=V_{x0}+A_x\cos (N\theta )+K\sin (\theta )$$

$$v_y=V_{y0}+A_y\cos (N\theta -\frac{\pi }{2}+\beta )+K\sin (\theta )$$

where:

• v_x is the cosine voltage.

• v_y is the sine voltage.

• A_x and A_y are the voltage amplitudes for the x and y axes that reflect the sensitivity mismatch.

• V_x0 and V_y0 are the voltage offsets for the 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:

$${\theta }_{out}=\arctan \left(\frac{v_y}{v_x}\right).$$

This figure shows the effects of the tumbling factor:

Variables

To set the priority and initial target values for the block variables before simulation, use the Initial Targets section in the block dialog box or Property Inspector. For more information, see Set Priority and Initial Target for Block Variables.

Nominal values provide a way to specify the expected magnitude of a variable in a model. Using system scaling based on nominal values increases the simulation robustness. You can specify nominal values using different sources, including the Nominal Values section in the block dialog box or Property Inspector. For more information, see System Scaling by Nominal Values.

Ports

Conserving

R — Rotational velocity for sensor positive probe

mechanical rotational

Mechanical rotational conserving port associated with the sensor positive probe.

C — Rotational velocity for the sensor negative probe

mechanical rotational

Mechanical rotational conserving port associated with the sensor negative (reference) probe.

yp — y-axis positive terminal

electrical

Electrical conserving port associated with the y-axis positive terminal.

Dependencies

To enable this port, set Output interface to Electrical connections.

yn — y-axis negative terminal

electrical

Electrical conserving port associated with the y-axis negative terminal.

Dependencies

To enable this port, set Output interface to Electrical connections.

xp — x-axis positive terminal

electrical

Electrical conserving port associated with the x-axis positive terminal.

Dependencies

To enable this port, set Output interface to Electrical connections.

xn — x-axis negative terminal

electrical

Electrical conserving port associated with the x-axis negative terminal.

Dependencies

To enable this port, set Output interface to Electrical connections.

Output

Angle — Rotational angle

physical signal

Rotational angle of the magnetic field in the x-y plane, returned as a physical signal.

Dependencies

To enable this port, set Output interface to Decoded angular position.

Parameters

Number of pole pairs — Number of pole pairs

2 (default) | scalar

Number of pole pairs.

X-axis voltage amplitude — x-axis voltage

2.5 V (default) | scalar

x-axis voltage amplitude.

Y-axis voltage amplitude — y-axis voltage

2.5 V (default) | scalar

y-axis voltage amplitude.

X-axis voltage offset — x-axis voltage offset

0 V (default) | scalar

Potential difference in the electric current flow through the electric conductor in the absence of external magnetic field on the x-axis.

Y-axis voltage offset — y-axis voltage offset

0 V (default) | scalar

Potential difference in the electric current flow through the electric conductor in the absence of external magnetic field on the y-axis.

Quadrature error — Quadrature error

0 deg (default) | scalar

Amount of quadrature error. Quadrature switching can decrease offset errors.

Tumbling coefficient — Tumbling coefficient

0 (default) | scalar

Tumbling coefficient, in degrees.

Output interface — Interface for decoded information

Electrical connections (default) | Decoded angular position

Port interface for the decoded information, specified as either Electrical connections or Decoded angular position.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2020a