Hello,
I am currently testing the rectification behavior of a Half-Bridge MMC model in PLECS.
I am using the same circuit configuration and parameters in both PLECS Standalone and RT Box, but I am observing different results between the two environments.
The test is performed without any closed-loop control. A three-phase AC voltage is applied to the MMC, and the natural rectification behavior is evaluated by monitoring the DC-link voltage.
The test sequence is very simple. When Grid_en is changed from 0 to 1, the three-phase AC grid voltage is ramped from 0 V to 10 × sqrt(2) kV.
In PLECS Standalone, the MMC shows the expected rectification behavior, and the DC-link voltage settles at approximately 10 × sqrt(2) kV.
However, when the same model is executed on the RT Box, the DC-link voltage rises above 10 × sqrt(2) kV and continues to increase instead of settling.
The purpose of this test is simply to verify the basic natural rectification behavior of the MMC. To isolate the issue as much as possible, I have removed the control functions and additional circuits that could potentially affect the result. Despite this, I have not been able to identify the reason for the difference between PLECS Standalone and RT Box.
Could you please advise on the following?
- What could cause the natural rectification behavior of the same Half-Bridge MMC model to differ between PLECS Standalone and RT Box?
- Are there any specific modeling considerations or settings required when performing this type of MMC rectification test on the RT Box?
- Is there a recommended way to resolve this issue?
I have attached the PLECS model used for the test for your reference.
Thank you.
MMC_Rectifying.plecs (163.2 KB)