PWM Generators

This example allows users to explore the FPGA-based PWM Generators and understand the effects of each configuration parameter on the generated signals. Four PWM generators are mapped to the switches of a pass-through circuit model, and the measured signals are displayed in VeriStand through the waveform engine.

The example is available as two separate VeriStand projects, one providing support for the PXIe-7868R FPGA card and the other for the PXIe-7891 FPGA card. Both projects demonstrate the same concepts and behave almost identically.

Example Directory	<Public Documents>\National Instruments\<NI VeriStand 20xx>\Examples\OPAL-RT\Power Electronics Add-On\PWM Generators
Project Path	<Machine Sensors>\Project\<NI PXIe-XXXX>\PWM Generators.nivsprj
Reference Documentation	PWM Generators

Opening and Deploying the Example

To avoid modifying the original example, make a local copy of the Example Directory shown above.
Open VeriStand and Browse to the VeriStand Project (.nivsprj) file at the Project Path in the copied directory.
Click Configure... to open the system definition file.
Enter the IP Address of the Real Time target in the Controller page.
If permissions are configured on the Real Time target, enter the credentials in the Username and Password fields.
Save and close the system definition file.
Click Operate >> Deploy.

Open the VeriStand Screen (.nivsscr) files and manipulate the parameters in the blue boxes to observe the resulting output signals. The configuration information displayed in grey is for informational purposes only; these parameters can only be modified from the system definition file while the project is undeployed.

Observing PWM Signals

Open Main.nivsscr and observe the signals on the three graphs. In this example, all four PWM Generators are operating at Frequency of 100Hz and a Duty Cycle of 50% by default.

Phase Shift Graph: Displays the effects of a 30° Phase Shift applied to PWM Generator 1 compared to PWM Generator 0 (with no phase shift).
Wave Mode Graph: Compares a Symmetric PWM waveform to an Asymmetric waveform.
Dead Time Graph: Shows PWM Generator 3 and its complement, configured with a Dead Time of 0.001 seconds.

Change the PWM Duty Cycles of any of the four generators and observe the effects on the respective waveforms. To modify any of the other PWM parameters displayed in grey, undeploy the simulation and edit the parameters in the system definition file on the PWM Generators page.