Ansys Motor-CAD: LAB Torque Speed Curves

Hello everyone, David Giglio here with Ozen Engineering. In this video, I will show you how to use ANSYS Motor-CAD to develop torque-speed curves and analyze how the losses of the motor affect the power output at high speeds. In this example, we go to the drive where ANSYS Motor-CAD is installed.

We go to the tutorials folder and select the BPM design traction folder. Inside here, there is an IPM traction lab torque speed project. We open this and then we see this model appear. There are three tabs that we will be using: model build, calculation, and electromagnetic.

In the model build tab, there is a sub-tab model options. We need to set up a saturation model and a loss model. The saturation model has three model types: 1. Fixed inductance type: uses the values of Ld, Lq, and the neutral flux of air gap to calculate electromagnetic performance.

These are assumed to be fixed and not changed with current magnitude or angle. 2. Saturation model single step: built of the D and Q axis flux linkages and how they vary with current magnitude and angle.

These are evaluated at a single rotor position and the D and Q flux linkages are assumed to be invariant of rotor position. 3. Saturation model full cycle: built of the D and Q flux linkages and how they vary with current magnitude and angle.

These are evaluated at average across a number of full electrical cycles. The number of electrical cycles and points per cycle is the same as those used for the torque calculation defined in the emagnetic model.

Under input data settings calculations, the loss model model types include: 1. Neglect model type: iron, magnet, sleeve, and banding losses are neglected in this model type. Copper losses are calculated using only the DC phase resistance.

This option is recommended only for initial machine sizing and design optimization as the accuracy is low. 2. Exhaust valve loss: the loss model model types include the exhaust valve loss. In this example, we are using the saturation model single step and model resolution course with 15 points.

We will select the neglect model type for the loss. Next, we go to the calculation tab and set the DC bus voltage to 720, maximum modulation index set to one, using a motor operating mode maximum torque per amp control strategy.

In the electromagnetic tab, we have the maximum torque per speed curve as our calculation type. We choose the speed of 15,000 rpm with a step size of 500 rpm and it's starting at 0 rpm. This is a maximum RMS current.

Select build model and once we have this model built, we go to electromagnetic, calculate electromagnetic performance. We will then have the torque-speed curve where we can select what curves to choose by going to graph settings plus selection.

We have selected shaft torque and shaft power for the white axis. We can then select the current speed curve and then we can select the phase advanced angle over here.

By controlling the phase advance angle, we can reduce the torque so that as torque is reduced, speed is increased and the back EMF is decreasing. The current is decreasing and the power is decreasing, the product of the speed and the torque achieves the constant power.

We can go back to graph settings and go to instead of shaft torque and power, we can unselect this and select the voltage RMS and phase advanced angle over here. In this example, only the DC losses of the windings are considered, all other losses are neglected.

We saw that the power output was very practically constant. Now, we're gonna run an example of including all the losses. We have opened up an example with the AC winding losses and windage losses considered to compare with the previous example where the only DC losses were considered.

Go to model, emagnetic, input data, losses, and select hybrid FEA. Then go back to model, lab, and update the saturation model type to full cycle and update the loss model type to FEA map. Select AC loss model hybrid method and update the model resolution to custom with the settings shown here.

Then in calculation, we have changed the maximum modulation index to 0. 97. Everything else is the same for the operating mode motor, control strategy, maximum torque per amp. And in the windage tab, we have this automatic calculation for the windage loss model. Now go to the Electromagnetic tab.

We have the same calculation type, maximum torque speed curve selected, the same speed definition, and the same current definition as well. Select calculate electromagnetic performance. Within a few seconds, get the results. And then we calculate the performance.

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