Question about loop analysis of boost converter(CPM)

[boxxang]

cpm boost converter

Hello. Everyone.
I am designing a current mode boost converter.
The Input voltage is from 1.5 to 2V, and output is 3v Fixed.
and Switching Frequency is 1MHz, and load current is 200mA.
Only 3 external components are allowed to use on board.
So, I can use inductor(2.2uH), Input capacitor(2.2uF), output Capacitor(2.2uF)
and I cannot change a value of external components.
For designing a boost converter, I am studying about transfer fuction of boost converter.

I understood in the book that current mode is more stable than voltage mode,
because large damping factor in current mode make the transfer function one pole system. (471 page in Fundamental of Power electronics)

So, I understood basically Quality factor(Q) of transfer function of current mode switching regulator is very small.

But, If I caculate the Q of boost converter(as specification I mentioned above),
It is not small. ( I used a equation in the book ,page 470 Fundamental of ---)
It is about 1.86, so It looks like quadratic pole system.

If there is anyone who tell me why this situation is occurred, please reply to my topic. ( I wonder if there is a way I can decrease Q value )
And In these case, let me know how I can compensate these system.

thanks in advance.

 

[ytliang]

boost cpm

I believe those equations are for CCM operation. Are you sure you are operating under CCM instead of DCM?

 

[boxxang]

boost converter analysis transfer

Yes, right.
I'd like to make the converter operate in CCM not DCM.