Rotor-Stator Electromagnetic Radial Force and

Shaft Deformation for a Hermetic Compressor

Flávio J. H. Kalluf

Marcos G. Dropa de Bortoli

Whirlpool / Embraco – Unidade Compresores

DESCRIPTION AND MOTIVATIONS

DESCRIPTION

EVALUATION OF A INTEGRATED (MAGNETIC-STRUCTURAL-THERMIC) SIMULATION OF A HERMETIC COMPRESSOR FOR REFRIGERATION

MOTIVATIONS

- THE MAGNETIC SOLUTIONS ARE USUALLY STAND-ALONE;

- THE SIMULATION PROGRAMS ARE NORMALLY IN VARIOUS DIFFERENT LANGUAGES, WHICH DIFFICULTS THE INTEGRATION;

- THE INTEGRATION MAKES THE ANALYSIS FASTER AND RELIABLE;

- THE LAST VERSIONS OF ANSYS WORKBENCH ALLOWS THE INTEGRATION OF MAGNETIC AND MECHANICAL SIMULATIONS.

INSIDE THE COMPRESSOR

VARIABLE-SPEED COMPRESSOR STATOR / ROTOR

The variable-speed compressors are the state-of-the-art motors for refrigeration

compressors, and requires an electronic control.

INSIDE THE COMPRESSOR

HEAT

RADIAL FORCE

The heat and the radial force are not usually calculated by the standard motor

simulation programs

RADIAL FORCE

PERFECTLY CENTERED

FORCES ARE BALANCED RESULTANT FORCE=0

RADIALLY DISPLACED

FORCES ARE UNBALANCED RESULTANT FORCE>0

An additional negative effect of the radial misalignment is the higher flux density

in one side of the stator, which can reduce the motor efficiency.

Higher

flux density

CURRENT SIMULATION METHOD

2D FEA SIMULATION

DEFORMATION ANALISYS

THERMAL ANALISYS

ANALYTICAL SIMULATION

PROPOSED SIMULATION METHOD

3D FEA SIMULATION (MAXWELL)

ANALYTICAL SIMULATION (RMxprt)

THERMAL ANALISYS (ANSYS MECHANICAL)

PROJECT SCHEMATIC

Input

ELECTROMAGNETIC

- Geometry - Eccentricity - Current

Output - Radial Force - Electrical Power

Input

STRUCTURAL

- Geometry - Radial Force

Output - Deformation

Input

THERMAL

- Geometry - Electrical Power

Output - Temperature

MAXWELL – RADIAL FORCE / POWER

RADIAL FORCE CURRENT DENSITY

ANSYS STRUCTURAL - DEFORMATION

RADIAL FORCE

DEFORMATION

ANSYS THERMAL - TEMPERATURE

CURRENT DENSITY

modeFRONTIER INTEGRATION

CONCLUSIONS AND NEXT STEPS

CONCLUSIONS

- The use of a multiphysics platform can increase the speed and precision of motor simulation;

- The integration of magnetic-structural-thermal simulations can be used by the optimization software (workbench node )

NEXT STEPS

-Use the integration for dynamic/transient simulation;

- Evaluate the multiphysics optimization in terms of speed and precision;

-Model the compressor internal temperature / influence of the shell;

- Close the force-deformation-force loop in the magnetic/structural simulation;

-Compare the obtained results with experimental data.