C2000 ePWM Developer’s Guide
Abstract
The enhanced pulse width modulator (ePWM) peripheral is a key element in controlling many of the power electronic systems found in both industrial and automotive applications. C2000™ real-time microcontrollers offer many differentiated features within the ePWM peripheral that allow for advanced control techniques. This application note focuses on an application use-case described within the introduction, demonstrating each of the features of the ePWM along with how to use SysConfig system configuration tool to set-up and program the desired outputs. SysConfig is a tool that exists integrated in Code Composer Studio™ (CCS) or as a standalone program that allows you to generate C header and code files using a graphical user interface (GUI). This application note was done using the TMS320F28388D device. However, the content in this application note is applicable to all devices with a Type-4 ePWM module. For more information on peripheral types, see the C2000 Real-Time Control MCU Peripherals Guide.
Trademarks
C2000™ and Code Composer Studio™ are trademarks of Texas Instruments.
All trademarks are the property of their respective owners.
1 Introduction
The ePWM module is separated into submodules, each with their own functionality. #FIG_RDT_LRW_WTB shows how the submodules are connected to each other. Throughout this application report, each of the different submodules is explained in detail.
Figure 1-1 Block Diagram for the ePWM ModuleThe application use-case that is discussed throughout this application report has the following criteria:
Use-Case
- Output frequency of 400 kHz for EPWM1/2/3
- Phase shift of 120° for EPWM2 with respect to EPWM1
- Phase shift of 240° for EPWM3 with respect to EPWM1
- Duty cycle of 45% for EPWM1/2/3
- Active high complementary signal pairs with 200 nsec of rising/falling edge delay for EPWM1/2/3
- Cycle-by-Cycle trip zone protection through comparator signal on EPWM2
- One-Shot trip protection through general-purpose input/output (GPIO) on EPWM3
- Interrupt generation every time the time-base counter equals zero on EPWM1
- Global loading to support asynchronous updates of action qualifier settings
- Link CMPA/CMPB of EPWM1 to EPWM2 and EPWM3
2 SysConfig
As mentioned in the abstract, this application report utilizes SysConfig in order to configure the ePWM module along with the other required components. Within SysConfig, each submodule of the ePWM module has its own grouping, including a Global Load and HRPWM grouping. If more general information about SysConfig is required, see the items listed in GUID-647B8A38-4C5C-4DC7-84EB-98340DDE5560.html#GUID-647B8A38-4C5C-4DC7-84EB-98340DDE5560.
Aside from being able to configure each of the submodules, the ePWM modules also have a "Global Parameters" section at the very top. These settings are used to enable information/warnings as well as affect how the code is being generated from the ePWM module.