Hello! I am currently building a PLECS model of a single-phase cascaded H-bridge rectifier for hardware-in-the-loop simulation on the RTbox3.The controller part, as shown in Figure 1, is loaded into the DSP controller connected to the RTbox3. The main circuit part is shown in Figure 2.
Figure 1
Figure 2
Therefore, how should I construct the SPWM output in the controller part to achieve phase-shifted carrier control for a four-stage single-phase cascaded H-bridge rectifier?
Which TI MCU are you using? Have you encountered any specific issues or feel like you’re not seeing the expected results?
Constructing phase shifted PWM is quite straightforward, for example with a fixed 90 degree shift between phases and 0.25 duty cycle is configured as below and produces the expected PWM outputs.
simple_phase_shift_pwm.plecs (19.4 KB)
The 28069 has some restrictions on how the PWM carriers can be synchronized. PWM1 can only trigger PWM2, PWM2 can trigger PWM3, and so on. However, it seems that the implementation is overly restrictive and cannot allow synchronization beyond ePWM3. I will report this to the TSP developers.
If you have other more modern TI C2000 devices available the model should work - this issue is specific to the 28069.
"Thank you for your support. Could you please recommend some TI C2000 MCU devices?
I’m not sure what’s available in your region. The more modern devices would be the F28P55X, F28P65X, and F29H85X. If you’re a) not optimizing a BOM but rather using the device mostly for control prototyping and b) using the LaunchPad form factor, then I would recommend the LaunchXL F29H85 as the most capable C2000 LaunchPad TI offers at this time and is at a very competitive price-point below the price of the LAUNCHXL-F28069M on TI’s website).
OK, I get it, Thanks for your guidance
