ACIM Torque Estimator

Estimate electromechanical torque and power

Since R2020b

• 

Libraries:
Motor Control Blockset / Controls / Control Reference
Motor Control Blockset HDL Support / Controls / Control Reference

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).

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).

• Open Model

Ports

Input

I_sd — D-axis stator current

scalar

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

Data Types: single | double | fixed point

I_sq — Q-axis stator current

scalar

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

Data Types: single | double | fixed point

ω_m — Mechanical speed of rotor

scalar

Mechanical speed of the rotor.

Data Types: single | double | fixed point

Output

T_e — Electromechanical torque

scalar

Electromechanical torque of the rotor.

Data Types: single | double | fixed point

P_e — 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.

Motor parameter input method — Type of motor parameters

Linear model with lumped parameters (default) | Non-linear model with D,Q-flux linkage LUTs

Since R2025a

Motor parameters that the block uses to generate power and torque estimates. Set the parameter to one of these values:

• Linear model with lumped parameters — Generate torque and power estimates using lumped circuit values for the machine inductances L_s ,L_r ,L_m , and the rated flux.

• Non-linear model with D,Q-flux linkage LUTs — Generate torque and power estimates using d-axis and q-axis flux linkage lookup tables.

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).

Dependencies

To enable this parameter, set the Motor parameter input method parameter to Linear model with lumped parameters.

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).

Dependencies

To enable this parameter, set the Motor parameter input method parameter to Linear model with lumped parameters.

Magnetizing Inductance (H) — Magnetizing inductance of induction motor

30e-3 (default) | scalar

Inductance due to the magnetizing flux (in Henry).

Dependencies

To enable this parameter, set the Motor parameter input method parameter to Linear model with lumped parameters.

Rated Flux (Wb) — Rated flux of motor

38.2e-3 (default) | scalar

Rated flux of the induction motor (in Weber).

Dependencies

To enable this parameter, set the Motor parameter input method parameter to Linear model with lumped parameters.

D-axis current breakpoint vector, id (A) — d-axis current lookup vector

[0, 150, 350, 500] (default) | vector

Since R2025a

The d-axis current lookup vector to use in the flux-linkage lookup tables (in percentage). The vector can have any number of elements.

Dependencies

To enable this parameter, set the Motor parameter input method parameter to Non-linear model with D,Q-flux linkage LUTs.

Q-axis current breakpoint vector, id (A) — q-axis current lookup vector

[0, 250, 500] (default) | vector

Since R2025a

The q-axis current lookup vector to use in the flux-linkage lookup tables (in percentage). The vector can have any number of elements.

Dependencies

To enable this parameter, set the Motor parameter input method parameter to Non-linear model with D,Q-flux linkage LUTs.

D-axis flux linkage LUT, FluxD (id,iq) (Wb) — Reference d-axis flux linkage lookup data

4.4e-2 * repmat([0, 150, 350, 500]', 1, 3) (default) | vector

Since R2025a

The d-axis flux linkage lookup table data (in weber).

Dependencies

To enable this parameter, set the Motor parameter input method parameter to Non-linear model with D,Q-flux linkage LUTs.

Q-axis flux linkage LUT, FluxD (id,iq) (Wb) — Reference q-axis flux linkage lookup data

2.1e-3 * repmat([0, 250, 500], 4, 1) (default) | vector

Since R2025a

The q-axis flux linkage lookup table data (in weber).

Dependencies

To enable this parameter, set the Motor parameter input method parameter to Non-linear model with D,Q-flux linkage LUTs.

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).

Extended Capabilities

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

HDL Code Generation

Generate VHDL, Verilog and SystemVerilog code for FPGA and ASIC designs using HDL Coder™.

HDL Coder™ provides additional configuration options that affect HDL implementation and synthesized logic.

HDL Architecture

This block has one default HDL architecture.

HDL Block Properties

ConstrainedOutputPipeline	Number of registers to place at the outputs by moving existing delays within your design. Distributed pipelining does not redistribute these registers. The default is 0. For more details, see ConstrainedOutputPipeline (HDL Coder).
InputPipeline	Number of input pipeline stages to insert in the generated code. Distributed pipelining and constrained output pipelining can move these registers. The default is 0. For more details, see InputPipeline (HDL Coder).
OutputPipeline	Number of output pipeline stages to insert in the generated code. Distributed pipelining and constrained output pipelining can move these registers. The default is 0. For more details, see OutputPipeline (HDL Coder).
SharingFactor	Number of functionally equivalent resources to map to a single shared resource. The default is 0. See also Resource Sharing (HDL Coder).

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

Version History

Introduced in R2020b

R2025a: Compute power and torque estimates using new block parameters

The Block Parameters dialog box now includes parameters that enable you to compute power and torque estimates from flux linkage lookup table data.