Ansys Motor-CAD: Lab Module Efficiency Maps, Duty Cycle, and Operating Points
Hello everyone, David Giglio here with Ozen Engineering, Inc. In this video, I will show you how to use ANSYS MotorCAD to develop efficiency maps, apply duty cycles to realistically model motor operation, and examine the operating points on the efficiency maps. We will also explore other maps and review open circuit and short circuit results.
Getting Started
- Navigate to the installation folder where MotorCAD is installed.
- Go to the tutorials folder, select the BPM design traction folder, and open the lab efficiency map project. This project has all the settings applied.
Configuration
- Notice that the AC loss model is set to the hybrid method. In the electromagnetic physics module's losses tab, the hybrid FEA AC winding loss is selected.
- In the lab physics module, with everything set up, the model is built. In the calculations tab, settings for drive, losses, temperature, etc., are applied.
- Windage losses are applied using automatic calculation. Bearing losses or custom losses are not included.
Efficiency Map and Duty Cycle
- In the electromagnetic tab, select the efficiency map and define the speed and current definitions for the parametric sweep.
- Select the smooth map option.
- In the duty cycle tab, choose the automotive drive cycle for highway motor operation. The MotorCAD help manual provides definitions for different automotive drive cycles.
- For highway conditions in the US region, typical speeds are under 60 miles per hour.
- Apply the selected drive cycle to the model, which includes vehicle model information such as math, rolling resistance, coefficient, speed, and air density.
Calculating Performance
- Go back to the electromagnetic tab and calculate e-magnetic performance to generate the efficiency map.
- Overlay the operating points for the duty cycle on the efficiency map.
- To generate the duty cycle, return to the duty cycle tab and calculate it. This will show the variation of shaft torque versus time, illustrating motor acceleration and deceleration.
- Input speed and torque to determine stator phase current and other output quantities.
- Select lab e-magnetic coupling and transfer the operating point to the magnetic model. Once solved, these operating points are transferred to the e-magnetic model.
Short Circuit and Open Circuit Tests
Short Circuit Test
- Go to the calibration tab and perform a short circuit test by clicking calculate test performance.
- The green curve represents the stator current, and the blue curve represents the braking torque.
- As the rotor spins, the magnets induce currents in the stator windings, increasing short circuit currents with speed until they level off.
- The stator current changes due to the non-linearity of the stator material's inductance.
- The braking torque is produced by the opposing magnetic field generated in the stator winding under short circuit conditions.
Open Circuit Test
- Select the open circuit option and run calculate test performance.
- The green curve shows back EMF versus speed, building up linearly as the rotor rotates.
- The blue curve represents drag torque, a mechanical resistive torque opposing motion.
- Initially, more shaft torque is needed to overcome resistive forces and get the rotor in motion. Once in motion, less torque is needed to increase speed.
Efficiency Map Analysis
- The efficiency map displays shaft torque along the y-axis, speed along the x-axis, and efficiency along the z-axis, represented by a color legend.
- Use the drop-down menu for the z-axis to select different quantities, such as stator copper losses or iron losses.
- In the tools tab, select saturation and loss maps to view different x and y quantities and outputs along the z-axis.
Contact us to learn about our organizational capabilities and request a demonstration to see how we can assist with your engineering projects. Ozen Engineering, Inc. is an ANSYS Elite channel partner, providing training, consulting services, and ANSYS software packages.
Thank you very much for watching. Please like, subscribe, and share this video.
Hello everyone, David Giglio here with Ozen Engineering. In this video, I will show you how to use ANSYS MotorCAD to develop efficiency maps and apply duty cycles to realistically model motor operation, looking at the operating points on the efficiency maps.
We will also look at other maps and open/short circuit results. In this example, go to the installation folder where MotorCAD is installed, navigate to the tutorials folder, select the BPM design traction folder, and open the lab efficiency map project. This project has all the settings applied.
Notice that the AC loss model is selected as the hybrid method. In the electromagnetic physics module, losses tab, the hybrid FEA AC winding loss is selected. With everything set up in the lab physics module, the model is built.
Then, in the calculations tab, these settings are applied for the drive, losses, temperature, etc., and windage losses are applied using automatic calculation. Bearing losses or custom losses are not included.
In the electromagnetic tab, select the efficiency map and define the speed and current definitions for the parametric sweep for these quantities. Select a smooth map, and in the duty cycle tab, we have selected the automotive drive cycle for highway motor operation.
In the model with the selected drive cycle applied, this has the vehicle model information for the math, rolling resistance, coefficient, and speed. Air density, etc., is included to model the mechanical properties of the vehicle.
Now, go back to electromagnetic calculate, and the efficiency map will be generated. We are showing the operating points for the duty cycle overlaid on the efficiency map. To generate the duty cycle, go back to the duty cycle tab, calculate duty cycle, and it'll show the duty cycle.
This shows the variation of the shaft torque versus time. The motor is accelerating and decelerating over time. To perform a short circuit test, click calculate test performance, and we'll get a curve showing the stator current and braking torque.
As the rotor spins, the magnets on the rotor induce currents on the stator windings that are short-circuited. With increasing speed, the short circuit increases and eventually levels off to a steady value.
The braking torque is produced because of the field generated in the stator winding under the short circuit, opposing the changing flux due to the rotor magnets. This results in a braking effect on the rotor.
In the open circuit selection, run calculate test performance, and we will get a curve showing the back EMF versus speed. As the rotor rotates, the EMF builds up linearly. The blue curve here is the drag torque, a mechanical resistive torque opposing the motion.
Initially, the rate of change of torque with respect to speed is higher. After a certain region, it takes less shaft torque to make a given change in speed. In the efficiency map, shaft torque along the y-axis and speed along the x-axis are the inputs.
The output is efficiency shown along the z-axis. By selecting the drop-down menu for the z-axis, we can select a different quantity to show along this z-axis, such as stator copper losses AC or iron losses of the stator.
On the tools tab, select saturation and loss maps, and we can also select the saturation and loss maps. Contact us to learn about our organization's capabilities and request a demonstration. Ozen Engineering Inc.
is an ANSYS Elite channel partner and provides training to use ANSYS tools, offers consulting services, and sells ANSYS software packages. Thank you very much. Like this video, like it, subscribe and share. Thank you very much.
