ACIM Torque Estimator

Estimate electromechanical torque and power

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• Motor Control Blockset / Controls / Control Reference

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Description

The ACIM Torque Estimator block generates electromechanical torque and power estimates for an induction motor. The block outputs the mathematically computed electromechanical torque for constant motor parameters. To measure an accurate torque value, we recommend that you use a physical sensor.

The block accepts feedback values of d- and q-axis stator current and mechanical speed as inputs.

Equations

If you select Per-Unit (PU) in the Input units parameter, the block converts the inputs to SI units before performing any computation. After calculating the output, the block converts the output back to per unit values.

These equations describe the computation of electromechanical torque and power estimates by the block.

$T_e=\frac{3}{2}p\left(\frac{L_m}{L_r}\right){\lambda }_{rd}{i}_{sq}$

$P_{\text{e}}=T_e\cdot {\omega }_{\text{m}}$

For detailed set of equations and assumptions, see Mathematical Model of Induction Motor.

where:

• $$p$$ is the number of pole pairs available in the motor.

• $L_m$ is the magnetizing inductance of the motor (Henry).

• $L_r$ is the rotor inductance (Henry).

• ${\lambda }_{rd}$ is the d-axis flux linkage of the rotor (Weber).

• $i_{sq}$ is the stator q-axis current (Amperes).

• $${\omega }_m$$ is the mechanical speed of the rotor (Radians/ sec).

Ports

Input

Isd — D-axis stator current

scalar

Stator current along the d-axis of the rotating dq reference frame.

Data Types: single | double | fixed point

Isq — Q-axis stator current

scalar

Stator current along the q-axis of the rotating dq reference frame.

Data Types: single | double | fixed point

ωm — Mechanical speed of rotor

scalar

Mechanical speed of the rotor.

Data Types: single | double | fixed point

Output

Te — Electromechanical torque

scalar

Electromechanical torque of the rotor.

Data Types: single | double | fixed point

Pe — Electromechanical power

scalar

Electromechanical power of the rotor.

Data Types: single | double | fixed point

Parameters

Number of pole pairs — Number of pole pairs available in motor

2 (default) | scalar

Number of pole pairs available in the induction motor.

Stator leakage inductance (H) — Leakage inductance of stator winding

6.81e-3 (default) | scalar

Inductance due to leakage flux linked to the stator winding (in Henry).

Rotor leakage inductance (H) — Leakage inductance of rotor winding

6.81e-3 (default) | scalar

Inductance due to leakage flux linked to the rotor winding (in Henry).

Magnetizing Inductance (H) — Magnetizing inductance of induction motor

30e-3 (default) | scalar

Inductance due to the magnetizing flux (in Henry)..

Rated Flux (Wb) — Rated flux of motor

38.2e-3 (default) | scalar

Rated flux of the induction motor (in Weber).

Input units — Unit of input values

Per-Unit (PU) (default) | SI Units

Unit of the input values.

Base Voltage (V) — Base voltage for per-unit system

24/sqrt(3) (default) | scalar

Base voltage (in Volts) for per-unit system.

Dependencies

To enable this parameter, set Input units to Per-Unit (PU).

Base Current (A) — Base current for per-unit system

5.3611 (default) | scalar

Base current (in Amperes) for per-unit system.

Dependencies

To enable this parameter, set Input units to Per-Unit (PU).

Base Speed (rpm) — Base speed for per-unit system

1500 (default) | scalar

Base speed (in rpm) for per-unit system.

Dependencies

To enable this parameter, set Input units to Per-Unit (PU).

Base torque (Nm) — Base torque for per-unit system

0.50072 (default) | scalar

Base torque (in Nm) for per-unit system. See Per-Unit System page for more details.

This parameter is not configurable and uses a value that is internally computed using other parameters.

Dependencies

To display this parameter, set Input units to Per-Unit (PU).

Base power (W) — Base power for per-unit system

111.4284 (default) | scalar

Base power (in W) for per-unit system. See Per-Unit System page for more details.

This parameter is not configurable and uses a value that is internally computed using other parameters.

Dependencies

To display this parameter, set Input units to Per-Unit (PU).

Model Examples

Field-Oriented Control of Induction Motor Using Speed Sensor

Implements the field-oriented control (FOC) technique to control the speed of a three-phase AC induction motor (ACIM). The FOC algorithm requires rotor speed feedback, which is obtained in this example by using a quadrature encoder sensor. For details about FOC, see Field-Oriented Control (FOC).

Extended Capabilities

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

Fixed-Point Conversion
Design and simulate fixed-point systems using Fixed-Point Designer™.