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Add PWM Driver Block

Step 4 of 7 in Add Hardware Drivers to Simulation Model and Deploy to Target Hardware

In the Simulink® Library Browser, add the ePWM block from C2000™ Microcontroller Blockset > F2837xD.

Configure the ePWM1, ePWM2, and ePWM3 blocks for generating the PWM pulse. In the ePWM block parameters dialog box, specify the pulse width modulation (PWM) counter period register value calculated from CPU frequency and PWM frequency. For center-aligned PWM, divide the computed value by 2.

PWM counter period = CPU clock frequency / PWM frequency / 2

For more details, see the TMS320f28379d processor ePWM peripheral.

In the F2837x/07x/004x/38x ePWM block parameters dialog box, update these settings to configure PWM1 to generate PWM pulses in the target hardware.

Tab and Parameter in ePWM BlockSettings

General > Module

ePWM1

General > Timer Period

Enter the PWM period value in the CPU clock cycle

  • PWM counter period = CPU clock frequency / PWM frequency / 2

  • For LaunchPad 28379D, clock frequency is 200 MHz. For PWM frequency of 20 kHz,

    PWM counter period = 200e6 / 20e3 / 2;

    PWM counter period = 5000

Counter Compare > Specify CMPA via

Input port

Counter Compare > CMPA initial value

Enter the PWM counter period/ 2 (2500)

Counter Compare > Specify CMPB via

Input port

Counter Compare > CMPB initial value

Enter the PWM counter period/ 2 (2500)

Deadband unit > Use deadband for ePWM1A

on

Deadband unit > Use deadband for ePWM1B

on

Deadband unit > Deadband polarity

Active high complementary (AHC)

Deadband unit > Deadband Rising edge (RED) period (0~16383)

15

Deadband unit > Deadband Falling edge (FED) period (0~16383)

15

Event Trigger > Enable ADC start of conversion for module A check box (only for PWM1)

on

Event Trigger > Start of conversion for module A event selection (only for PWM1)

Counter equals to period (CTR=PRD)

Rename the block as ePWM1.

In the F2837x/07x/004x/38x ePWM block parameters dialog box, update the settings to configure PWM2 and PWM3 to generate PWM pulses in the target hardware. PWM2 and PWM3 are synchronized with PWM1. Follow ePWM1 configurations (other than Event Trigger) and add these configurations.

Tab and Parameter in ePWM BlockSettings

General > Module

ePWM2

General > Timer Period

Enter the PWM period value in the CPU clock cycle

  • PWM counter period = CPU clock frequency / PWM frequency / 2

  • For LaunchPad 28379D, clock frequency is 200 MHz. For PWM frequency of 20 kHz,

    PWM counter period = 200e6 / 20e3 / 2;

    PWM counter period = 5000

General > Synchronization action

Set counter to phase value specified via dialog

General > Counting direction after phase synchronization

Count up after sync

General > Phase offset value (TBPHS)

0

Counter Compare > Specify CMPA via

Input port

Counter Compare > CMPA initial value

Enter the PWM counter period/ 2 (2500)

Counter Compare > Specify CMPB via

Input port

Counter Compare > CMPB initial value

Enter the PWM counter period/ 2 (2500)

Deadband unit > Use deadband for ePWM1A

on

Deadband unit > Use deadband for ePWM1B

on

Deadband unit > Deadband polarity

Active high complementary (AHC)

Deadband unit > Deadband Rising edge (RED) period (0~16383)

15

Deadband unit > Deadband Falling edge (FED) period (0~16383)

15

Rename the blocks as ePWM2 and ePWM3.

The range varies from 0 to PWM_counter_period. PWM outputs when PWM up-counter matches CMPA and PWM down-counter matches CMPB. By default, the system inputs a duty cycle of 50% by selecting PWM counter period / 2.

On the Event Trigger tab of PWM1 module, configure the ADC start of conversion event to begin when the PWM counter equals the PWM period.

Synchronize the ePWM2 and ePWM3 blocks with the ePWM1 block by setting the synchronization timing to the moment when the PWM counter equals to zero in the ePWM2 and ePWM3 blocks.

The ePWM blocks expect the duty cycle value to range from 0 to the PWM counter period value (5000). The Control_System subsystem outputs the PWM in the range -1 to 1. The model needs to scale the output to 0 to 5000 (PWM counter period value).

For simulation, add a variant source/sink to the hardware driver block for simulation and code generation.

Add Hardware Drivers to Simulation Model and Deploy to Target Hardware
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