Synchronous Machine compatibility issues with 3 level PWM rectifier

I'm working on a ship distribution model with medium voltage DC distribution. As part of this, I need a synchronous steam turbine generator (4160 V, 36 MVA) with a PWM rectifier capable of a controlled 5kV DC output. I have a working steam turbine generator, and a PWM rectifier (slightly modified from the power_3levelVSC example in Simulink). The steam generator works fine when coupled to an AC load or even a 3-arm bridge rectifier. The PWM rectifier works great when coupled with an infinite source.

The file can be downloaded here: Model Download

Unfortunately, when the steam turbine is connected to the PWM rectifier, it causes extreme distortion of the AC side. This causes an unreasonable DC output (Ramping up past 25kV DC). Is there any way to modify my model to fix this? I copied a picture of my project:

Answer 1

[Sabin]

There seems to be some integration issues. Two systems can work well in isolation but can give wrong results when you put together if they are not configured properly. It seems there are a few potential issues. One is the conversion from SI to per unit in the controller. The transformer is configured to 30e6 VA nominal power and voltage phase to phase 4160Vrms primary and 2400Vrms secondary. The AC measurement is done on primary side. However, in the DC Regulator the Nominal Voltage phase to phase is set to 600 V and nominal power to 500e3 VA. Secondly, the controllers may need retuning. As it is the controllers are saturated and therefore getting the wrong results.