Thank you very much for your detailed explanation. Your comments have helped me better understand the limitations of my current PWM implementation.
I understand that the explicit triangular carrier comparison and Boolean gate signals may introduce duty-cycle quantization and prevent the use of sub-cycle averaging.
However, my current experimental setup does not permit additional physical connections between the RT-BOX digital output and digital input ports.
I have previously tested the Half Bridge modules in Sub-cycle average mode by directly applying duty-cycle reference signals. Although this significantly improved the voltage waveforms before the grid-inductance step, the oscillatory response after the step was different from that of the original high-accuracy switched model.
This is particularly important because my research focuses on stability analysis. The system should remain stable when the external grid inductance is 2 mH and exhibit an oscillation around 800 Hz when it increases to 5 mH.
The original PWM implementation also includes a 100 μs delay.
Could you please advise on the following points?
-
When directly applying duty-cycle signals to the Half Bridge modules in Sub-cycle average mode, how should the original PWM sampling behavior and 100 μs delay be represented?
-
Is the direct duty-cycle average model expected to reproduce the same small-signal stability characteristics as the original switched model, particularly near an LCL resonance?
-
Is there any alternative supported approach that provides sub-cycle PWM accuracy entirely within RT-BOX 1, without external digital loopback wiring?
My goal is to preserve the original control parameters and stability characteristics while improving the real-time simulation accuracy.
Thank you again for your assistance.