I think you face problem for  selecting the ∆Vo, ∆I other parameter you know beforehand, ∆Vo can be selected  how much ripple can be allow  e.g. allow  10% of V0 or 1% of V0 like so.  for  ∆I also it can be defined as 1% of Iin or 10 % of Iin.

Please find the attachment.

Basically 3 points to consider :

1. switching frequency -- its trade off between capacitor,Inductor value.

2. Ripple voltage & Inductor ripple current

3. Input voltage & output voltage specifically.

Please find the attachment.

In my experience, usually, we will do a superficial design calculation and find approximate C,L values. later we consider the C,L values values which are available in market and which are very close to your calculations. once we have C,L values from market, we can again do re-calculate to achiever highest Output voltage by adjusting Frequency, Ripple, etc.

So please consider the below design as reference, they will not be final in real system design.

As described earlier, the ripple voltage and current are set by the developer. It is as per the requirement of your system. Sensitive equipments are protected by keeping lower values of ripple voltage and current. For the duty cycle, it is usually kept close to 0.5 but again this depends upon your requirements and control strategy that you are implementing for your converter. Keep in mind that a very low duty cycle has a negative effect as the MOSFET will be turned on for a very short time and in that short time it will have to deliver the same amount of power that it can deliver with d=0.5. In other words, the VI characteristics play a critical role in deciding the working of the switch in terms of power dissipation and safe operation.

Please refer to these articles:

https://www.researchgate.net/publication/309716325_Designing_And_Simulating_Of_Micro-controller_Based_on_PWM_Solar_Charge_Controller

https://www.researchgate.net/publication/315692275_Maximum_Power_Point_Tracking_Control_of_PV_Electronic_System_using_Neural_Network

Article ‫ Designing And Simulating Of Micro-controller Based on PWM ...

Conference Paper Maximum Power Point Tracking Control of PV Electronic System...

Thank you all for your answer