Tuning multiple cascaded PI controllers in a model

Hello

I have a model shown in the picture below containing three parallel dc sources connected to a single resistive load through 3 boost converters.Each converter is controlled with a pi voltage controller and a pi current controller.The current controller output is sent to a 5khz pwm generator:

I have trouble with tuning my pi controllers with the workflow described here .I use the option identify new plant but for example i get these data for voltage controller1 which can't work properly to tune PI parameters:

I don't know to start tuning with which of the 6 controllers I have in my model.Does it affect the tuning process?What did I do wrong that I can't tune my controllers with this work flow?

I attach my model here to see if you can help me.Thanks in advance.