PWM-Generator System Overview
(this page is under construction)
The PWM-Generator Add-On for EVAL boards simplifies setup and testing by providing all PWM signals required to stimulate 3-phase B6 inverter topologies. The Generator is based on an STM32L432KCU6 Nucleo32 development board and is fully controlled via USB from a host running a Windows 10 OS. A small GUI application on the host controls all functions of the PWM-Generator.
Output Signals & Pin-Out
Proposed Level Shifter Interposer Board
In cases where Eval-Boards expect 5V logic (TTL) input signals, level-shifting from 3.3V logic of the PWM Generator is required. This could be achieved by a level-shifter interposing board. In order to facilitate usage and minimize p.c.b. real estate, such a level-shifter board could also accommodate the PWM-Generator in a piggy-back fashion.
A GENPRES (generator present) signal is provided to the host eval board which can be modified by the host in order to disable the PWM-Generator’s outputs.
Physical Dimensions for EVAL-Board Integration
Computer running Windows 10
First, install the ADI
PWM generator software. This will also copy the firmware for the STM32L432 NUCLEO on your computer, which will then be transferred to the NUCLEO in a later step. Do not start the application yet. The installation directory is C:\Analog Devices\SoftwareModules\PwmGenerator-Rel1.0.0
Install the STM32CubeProgrammer. Connect the STM32L432 NUCLEO board to your computer. The red LED on the NUCLEO board will light up. Open the STM32CubeProgrammer app:
On the right hand pane, make sure that the connection type is set to ST-LINK, then click “Connect”. The log window should report a successful connection as “Data read successfully” (the data displayed in the data window may be different). Note that the NUCLEO LED is flashing in red/green.
3. Install the PWM generator firmware on the NUCLEO board: click on the “Open file” tab and open the firmware “adi_pwm_gen.hex” in
Now, click on the “Download” button to download the firmware onto the NUCLEO. Click OK to confirm the completion of the download process. Your STM32L432 NUCLEO is now ready to run as a PWM generator. Close the STM32CubeProgrammer.
Using the PWM Generator
1. Start the PWM generator software (PGS) pwm_gen_gui.exe in
2.Select the correct COM port in the drop-down list. The PGS will immediately connect to the NUCLEO board:
3.Now you can set the PWM parameters according to your requirements:
PWM Frequency: Carrier frequency ouf the PWM outputs (1kHz .. 250 kHz
PWM Deadtime: Deadtime of signal transitions between associated high-side and low-side PWM outputs.
Modulation Frequency: Modulation frequency applies to all six output channels. A modulation frequency of 0 Hz allows for static testing at a fixed (“frozen”) modulation depth, set by
Modulation Amplitude: Sets the peak modulation depth on all PWM channels. A modulation of 0 sets all PWM outputs to fixed 50 % duty cycle, a modulation amplitude of 1 sets the PWM outputs vary between 100 % and 0% duty cycle according to the Modulation Frequency setting.
Modulation type: Lets you choose from either pure sine modulation or sine + 3rd harmonic modulation (actually, a space modulation pattern is implemented). Oscillograms show typical PWM-generator waveforms after 1kOhm / 100 nF low-pass filter on each output.
Finally, click on “Apply” to send the changes to the PWM generator, which will then take immediate effect. You can then “Save” and “Load” these settings for later use.