1. PID autotuner can only work for the plants which are linearized or which can be linearized. to work with autotuner the Matlab first linearizes the plant and then finds the PID gain values but in the case of Power converter, it results in zero linearization because of the discontinuities such as MOSFET blocks and PWM logic and hence it can not autotune the PID.

To solve this issue use simulation input/output data to estimate a transfer function of the system and then tune the response.

Let's consider a boost convertor which is set to fluctuate the output voltage between 50 and 55 with a closed-loop PI controller. 

In the above image, the logic of the converter and it's initial values of the PI are clear, as this is not a stunned PI controller the output on the right of the image can be seen, which is not close to 50 and 55. 

In order to get the desired output, this PI controller needs to be tunned with the method of simulation input/output data -

- First step Identifying new plant by giving an input to the system and observing the error -

Through applying this step we obtain plant identification data and based on this identified data we can modify our new plant furthermore as per the understanding of the original plant by adding a pole or zero or other settings.(as shown below)

Once the plant has been fully identified we can use the auto estimate option to get the design of the controller and further tune the controller as per our requirements and obtain the values of the PID gains. (shown below)-

Once the desired controller design is set the values of the PID are exported back to the PID block. and again the result is observed with new values. - 

In the above image it can be seen with new PID values now the result is as desired. 

2. In real-world application all the signals are continuous so when a power converter is used the input control signal as well as the output of the power converter are continuous signals. But while designing a controller for a microprocessor the control has to be in the digital domain so that it can be implemented. this creates a difference between the signal nature and to eliminate this difference ADC OR DAC blocks are used. 

when the output from the power converter is coming out it is also fed into the digital controller (closed-loop control) but an ADC block is required to eliminate the signal nature difference between both the components similarly when the output from the controller goes to the power convertor it is of digital nature and needs to be converted into continuous signal hence a DAC is required. 

3. organizational chart of people working at the powertrain manufacturing company -