Electric Motor Component

Description

The electric motor duty cycle defines the load cycle that the motor would experience during its operation. This temperature-driven cycle determines if the motor is suitable for its task or requires additional cooling or other changes.

A duty cycle defines a motor’s operational load, including the start/stop frequency, braking, and load variations.

The Flow Simulator electric motor component is designed for integrated duty cycle analysis with Altair's FluxMotor, streamlining user input and results processing. It requires FluxMotor and is not for standalone use.

Quick Guide for the Electric Motor Component in the User Interface

The Electric Motor Component (EMC) is available under the “COMPONENTS” section in Element Library. The dotted lines from the component show which thermal nodes are associated with it for duty cycle analysis.
Figure 1.


  1. An EMC does not have a chamber association. You can drag-and-drop it from the Element Library.
    Figure 2.


  2. Use Browse to select a loss file for the duty cycle. The Loss File Full Path is automatically filled.
  3. The Losses section defines the set of thermal nodes associated with each part of an Electric Motor, which contribute to the losses in the duty cycle. This topic refers to each part of the Electric Motor as a Loss type. “Loss” refers to inefficiencies in the electric motor that result in heat generation. The heat generated is applied to the thermal nodes in the Flow Simulator model.
    Figure 3.


For example, if you select Losess > Winding, the following dialog is displayed:
Figure 4.


Use this dialog to define which nodes are designated as "Winding" in the Electric Motor they are analyzing.
  1. Use Select from View to select the thermal nodes manually from the model or give a range of Thermal Node IDs using "+". If you use “+”, then the following dialog is displayed:
    Figure 5.


    From the Object Selection dialog, Thermal Node is the only available option.

    Use "," to select the item ID or use "-" to define a range.

  2. Use Add Tnode to individually define the Thermal Node IDs.
  3. Loss Scale defines the geometric dependance of the loss that has been calculated in each node of any part of the electric motor. This must be user-provided. The default is 1.

Electric Motor Component Inputs

Electric Motor Component (EMC) inputs.
Table 1. Element-specific Input Variables
Index UI Name (.flo label) Description
1 Duty Cycle

(DUTY_CYCLE)

 TRUE: Turns on the Duty Cycle calculation.

FALSE: Turns off the Duty Cycle calculation. Use this mode for post-processing, which is planned for a future release,

Default: TRUE
2 Loss File Name

(DUTY_CYCLE_FILE_NAME)

 Use Browse to select the loss file for the Duty Cycle Calculation.

Displays the loss file name.
3 Loss File Full Path

(DUTY_CYCLE_FILE_FULL_PATH)

 Automatically populated. This displays the full path to the loss file for the duty cycle calculation.
4 DUTY_CYCLE_FILE_REL_PATH Only in the .flo file; automatically populated. This path is used first when Flow Simulator loads the loss file for the duty cycle calculation. If it fails to load, the full path is used.
5 Losses

(Not in the .flo file)

 This section lists all parts of the electric motor, which participate in the loss calculation in duty cycle:
  • Magnet
  • Winding
  • Stator
  • Rotor
  • Bearing
6 Losses > Magnet > Tnode Id

(MAGNET_NODES)

 Use this to define which nodes are designated as “Magnet“ in the electric motor they are analyzing.
7 Losses > Magnet > Loss_Scales

(MAGNET_LENGTH_SCALES)

 Defines the geometric dependance of the “Magnet” loss that has been calculated in each node of any part of the electric motor.

Default: 1.0.
8 Losses > Winding > Tnode Id

(WINDING_NODES)

 Use this to define which nodes are designated as “Winding“ in the electric motor they are analyzing.
9 Losses > Winding > Loss_Scales

(WINDING_LENGTH_SCALES)

 Defines the geometric dependance of the “Winding” loss that has been calculated in each node of any part of the electric motor.

Default: 1.0.
10 Losses > Stator > Tnode Id

(STATOR_NODES)

 Use this to define which nodes are designated as “Stator“ in the electric motor they are analyzing.
11 Losses > Stator > Loss_Scales

(STATOR_LENGTH_SCALES)

 Defines the geometric dependance of the “Stator” loss that has been calculated in each node of any part of the electric motor.

Default: 1.0.
12 Losses > Rotor > Tnode Id

(ROTOR_NODES)

 Use this to define which nodes are designated as “Rotor “ in the electric motor they are analyzing.
13 Losses > Rotor > Loss_Scales

(ROTOR_LENGTH_SCALES)

 Defines the geometric dependance of the “Rotor” loss that has been calculated in each node of any part of the electric motor.

Default: 1.0.
14 Losses > Bearing > Tnode Id

(BEARING_NODES)

 Use this to define which nodes are designated as “Bearing“ in the electric motor they are analyzing.
15 Losses > Bearing > Loss_Scales

(BEARING_LENGTH_SCALES)

 Defines the geometric dependance of the “Bearing” loss that has been calculated in each node of any part of the electric motor.

Default: 1.0.

Electric Motor Component Duty Cycle Calculations

Loss File
The Loss file contains tables of losses for each part (loss type) of the electric motor that is being analyzed. FluxMotor creates the file as part of the duty cycle analysis.
Figure 6.


For each loss type (for example, Stator), tables of losses are provided for various temperature levels (°C). These temperature levels range from the minimum to maximum temperature that the motor is expected to experience during the duty cycle. The image above shows only a part of the table of a loss type.
The first row of the table contains the motor torque. Unit: Nm.
The first column of the table contains the motor speed. Unit: RPM.
The rest of the table includes losses corresponding to the speed and torque defined at that temperature level. Unit: W.
Figure 7.


In FluxMotor, losses are depicted as area graphs for each temperature level. These are converted to tables in the loss data file to be interpreted by the Electric Motor Component in Flow Simulator for the duty cycle analysis.
The NANs in the loss file mean that no data is available for those torque and speed values. This is displayed as the white section of the area graph for each temperature level in FluxMotor.
Duty Cycle Operational Load Definition
The operational load for the duty cycle is defined as a Mission in Flow Simulator. Use Solver > Analysis Setup > Cycle/Mission:
Figure 8.


The operational load for the duty cycle is defined with TIME, the TORQUE, and rotor1 (SPEED) for the transient analysis.
The mission parameters TIME and TORQUE are required to be named for Flow Simulator to recognize them as key operational load parameters.
The SPEED operational load column can be user-defined (rotor1 in this case). This is specified in Solver > Analysis Setup > Reference Conditions under Transient Engine Cycle Input > Shaft #1 Rotor Speed (RPM) as shown below:
Figure 9.


The mission table contains a “Mission Number”, which is selected in Solver > Analysis Setup > Transient Run Control Parameters > Active Transient Mission ID.
Figure 10.


Calculate Losses
The calculation requires two steps:
  1. Each time step:

    For each loss type (Magnet, Stator, and so on), a table of interpolated loss values is created for each temperature level for the speed and torque given in the mission table, corresponding to that time step using bilinear interpolation. This is created at the start of each time step and is used for all internal thermal iterations of that time step.

  2. For each internal thermal iteration:
    • Find the average temperature for magnet nodes and winding nodes from the thermal analysis of the motor.
    • Use the table of interpolated loss values, created at the start of the time step, to perform bilinear interpolation for the average magnet and winding temperature for each loss type.
    • Multiply the geometric dependance of the nodes (as defined in Loss Scale for a loss type) to the loss calculated for each loss type. This provides the individual losses to be applied to each node of a loss type (Magnet, Stator, and so on).
    • Apply the losses to each node for further thermal analysis.

Electric Motor Component Outputs

The following table contains details about the component output variables.
Name Description Units
ELECTRIC MOTOR COMPONENT The component ID. (number)
SPEED The speed calculated using interpolation for the current Time as provided in the mission table. Revolutions/minute
TORQUE The torque calculated using interpolation for the current Time as provided in the mission table. Ft-lb, N-m
AVERAGE MAGNET TEMPERATURE The calculated Magnet temperature averaged over all Magnet nodes for the current time step. °K, °F
AVERAGE WINDING TEMPERATURE The calculated Winding temperature averaged over all the Winding nodes for the current time step. °K, °F
LOSS The name of the loss type for the results. The subsequent results are for this loss type, until we see a different Loss type listed.

All five Loss types are listed in each EMC result section.

 No units

Character string
TNODE This column of the result table specifies the thermal node IDs, which were defined for each loss type.

Displayed under the LOSS section for each loss type and is defined for all five loss types.

 number
TT This column of the result table specifies the temperature reached by each thermal node during the current time step.

Displayed under the LOSS section for each loss type and is defined for the five loss types.

 °K, °F
NODAL_HEAT This column of the result table specifies the loss calculated in each thermal node in the current time step.

Displayed under the LOSS section for each loss type and is defined for the five loss types.

 BTU/s, W
AVG TEMPERATURE The temperature averaged over all nodes for every loss type for the current time step.

Displayed under the LOSS section for each loss type and is defined for the five loss types.

 °K, °F
TOTAL LOSS The sum of losses in each node of a loss type. This displays the total loss from a given part, such as Magnet, Stator, and so on, of an electric motor.

Displayed under the LOSS section for each loss type and is defined for the five loss types.

 BTU/s, W