RrL Estimator

Estimate rotor resistance (R_r), magnetizing inductance (L_m), stator leakage inductance (L_ls), and rotor leakage inductance (L_lr) 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 (R_r), magnetizing inductance (L_m), stator leakage inductance (L_ls), and rotor leakage inductance (L_lr) 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 R_r, L_m, L_ls, and L_lr.

Examples

Estimate Induction Motor Parameters Using Parameter Estimation Blocks

Uses the parameter estimation blocks provided by Motor Control Blockset™ to estimate these parameters of an AC induction motor (ACIM):

• Open Model

Ports

Input

Iabc — Three-phase current response

scalar

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

Vdc — DC link voltage

scalar

DC bus voltage that you provide to the inverter.

Data Types: single

StartStop — Control signal for L_d estimation

logical

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 R_r, L_m, L_ls, and L_lr values.

Data Types: Boolean

Config — Bus signal input

bus

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

Category	Configuration element			Units
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

Vabc — a, b, and c-axis stator reference voltage components

scalar

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

Data Types: single

Rr — Estimated rotor resistance

scalar

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

Data Types: single

Lm — Estimated magnetizing inductance

scalar

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

Data Types: single

Lls — Estimated stator leakage inductance

scalar

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

Data Types: single

Llr — Estimated rotor leakage inductance

scalar

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

Data Types: single

Log — Debug signals

bus

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

Debug signal			Description	Units
Id			D-axis current	Amperes
InjFreq			Frequency that the block currently injects	Hertz
status		0	Did not complete estimation	-
		1	Estimation 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