# ACIM Mechanical Parameter Estimator

Estimate rotor inertia and viscous damping of AC induction motor (ACIM)

*Since R2023a*

**Libraries:**

Motor Control Blockset /
Parameter Estimation /
ACIM Parameter Estimation

## Description

The ACIM Mechanical Parameter Estimator block uses the phase currents and voltages, DC voltage across the motor, motor speed, magnetizing current, rotor and complete motor resistances, magnetizing and stator leakage inductances, as well as the other test configuration elements to compute the following mechanical parameters of an induction motor:

Rotor inertia (

*J*)Viscous damping (

*B*)

The block runs the motor using closed-loop field-oriented control (FOC) with a limited
speed. While running the motor, the block also runs the tests to estimate viscous damping
(*B*). After a preconfigured duration, the block concludes these tests to
compute *B*, and then triggers coast-down by shutting down all six inverter
switches. The coast-down results in a gradual decline in the motor speed, which eventually
reaches zero. The block measures the time taken by the motor to reach a speed of zero and uses
it to calculate the rotor inertia (*J*).

## Examples

## Ports

### Input

### Output

## Extended Capabilities

## Version History

**Introduced in R2023a**