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RrL Estimator

Estimate rotor resistance (Rr), magnetizing inductance (Lm), stator leakage inductance (Lls), and rotor leakage inductance (Llr) of AC induction motor (ACIM)

Since R2023a

Libraries:
Motor Control Blockset / Parameter Estimation / ACIM Parameter Estimation

Description

The RrL Estimator block computes the rotor resistance (Rr), magnetizing inductance (Lm), stator leakage inductance (Lls), and rotor leakage inductance (Llr) of an AC induction motor using the phase currents, DC voltage across the motor, and the test configuration elements.

To estimate these values, the block injects the following three signals across the motor phases:

  • First low-frequency signal (of varying voltage)

  • Second low-frequency signal (of varying voltage)

  • High-frequency signal (of fixed voltage)

Using the given initial voltage and the step size, the block performs a voltage sweep on the first and second low-frequency signals until the resulting motor phase current becomes equal to 50 percent of the motor rated current. At this point, the block measures the phase difference between the injected voltage (of the low-frequency signals) and the resulting current response to estimate Rr, Lm, Lls, and Llr.

Ports

Input

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The three-phase current response of the motor measured by the current sensors.

Note

Providing phase-c current input is optional. The block functionality is not impacted if you do not provide the phase-c current input.

Data Types: single

DC bus voltage that you provide to the inverter.

Data Types: single

Signal that either starts or stops the estimation process:

  • 1 (rising edge of a pulse) — This signal initiates the estimation process.

  • 0 (falling edge of a pulse) — This signal immediately stops the estimation process. If you interrupt the estimation process abruptly before completion, the block does not compute or output the Rr, Lm, Lls, and Llr values.

Data Types: Boolean

This table summarizes the expected configuration elements in the bus signal input.

CategoryConfiguration elementUnits

Elements for motor and inverter hardware

Number of pole pairs

-

Rated frequency

Hz

Nominal motor current

A

Nominal voltage

V

Maximum measurable inverter current

A

Board resistance

ohm

Current sense gain

A/ADC Count

Voltage sense gain

V/ADC Count

Elements for estimating magnetizing current Id0

Measurement time

seconds

Open-loop ramp time

seconds

Elements for estimating motor resistance (Rs)

Estimation time

seconds

Vd reference voltage 1

PU voltage

Vd reference voltage 2

PU voltage

Elements for estimating rotor resistance (Rr), magnetizing inductance (Lm), stator leakage inductance (Lls), and rotor leakage inductance (Llr)

Frequency 1 as a ratio of rated frequency

PU frequency

Frequency 2 as a ratio of rated frequency

PU frequency

High frequency for Lm

Hz

Start voltage for voltage sweep

PU voltage

Voltage step for voltage sweep

PU voltage

High-frequency injection voltage

PU voltage

Elements for estimating motor inertia (J) and friction constant (B)

Closed-loop speed duration

seconds

Closed-loop speed

RPM

Iq Reference current for FOC

PU current

Proportional gain

-

Integral gain

-

Lower speed limit for inertia estimation

RPM

-

Parameter estimation sample time

seconds

You can connect this input port to the Config output port of the ACIM Parameter Estimation Configurator block.

Data Types: single

Output

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Stator reference voltage components along the a, b, and c axes of the abc reference frame.

Data Types: single

Estimated rotor resistance of the induction motor (in Ohms).

Data Types: single

Estimated magnetizing inductance of the induction motor (in Henry).

Data Types: single

Estimated stator leakage inductance of the induction motor (in Henry).

Data Types: single

Estimated rotor leakage inductance of the induction motor (in Henry).

Data Types: single

Debug signals that the block provides for examination. The bus includes these debug signals.

Debug signalDescriptionUnits

Id

D-axis current

Amperes

InjFreq

Frequency that the block currently injects

Hertz

status

0Did not complete estimation

-

1Estimation completed successfully

-

Vd

D-axis voltage

Volts

Data Types: single

Extended Capabilities

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

Version History

Introduced in R2023a