SPRACY3 June   2021 TMS320F280023C , TMS320F280025C , TMS320F280025C-Q1 , TMS320F280040C-Q1 , TMS320F280041C , TMS320F280041C-Q1 , TMS320F280048C-Q1 , TMS320F280049C , TMS320F280049C-Q1 , TMS320F28076 , TMS320F28379D , TMS320F28379D-Q1 , TMS320F28379S , TMS320F28386D , TMS320F28386D-Q1 , TMS320F28386S , TMS320F28386S-Q1 , TMS320F28388D , TMS320F28388S , TMS320F28P650DH , TMS320F28P650DK , TMS320F28P650SH , TMS320F28P650SK , TMS320F28P659DK-Q1

 

  1.   Trademarks
  2. 1Introduction
  3. 2Design Overview
  4. 3CLB Implementation
    1. 3.1 CLB Input Selection
    2. 3.2 Counter and FSM Configuration
    3. 3.3 CLB Output
    4. 3.4 Completed Design
  5. 4Normal Operation With CBC Protection Configuration
    1. 4.1 CBC Protection Configuration
    2. 4.2 Swapping EPWM Configurations During Zero Cross Point
  6. 5Other Considerations
    1. 5.1 Trip Sourced From CMPSS
    2. 5.2 Extend to 3 Phase Inverter
      1. 5.2.1 Input Selection
      2. 5.2.2 Output Selection
    3. 5.3 Achieve 2 Level Protection Scheme
  7. 6Test Results
  8. 7References

2 Design Overview

Figure 2-1 shows the expected EPWM protection results with CLB during positive cycle and negative operation.

In the given example, EPWM1A/2B/1B/2A are used for S1/2/3/4 control, respectively. The trip signal is simulated and generated with an EPWM output, EPWM8A here, for the validation of different trip conditions, including trip sustaining within or across one EPWM cycle.

Taking positive cycle operation as example, shown in 'A' of Figure 2-1, whenever the trip event occurs, EPWM1A and EPWM1B, which are configured with cycle-by-cycle tripping (CBC) action, are shut down immediately, while EPWM2B will be forced low after a delay t2. Besides, when the trip event disappears, EPWM2B will turn high immediately, which is also aligned with the basic recover requirement. The CLB signal is the key internal signal for the delayed trip feature, and EPWM1B and EPWM2B are actually the result of the AND logic of the initial EPWM output (EPWM1B’ and EPWM2B’) and CLB signal.

Figure 2-1 Expected EPWM Protection Logic With CLB