Output Voltage & Output Current Relationship in Buck Converter

[QutabBaig]

Hi

[In context of determining Maximum Power Point Tracking (MPPT) for charging 12 V, 3 Ah battery using 24 V solar panels]

I m designing a buck converter to track Maximum power point of PV panel for charging 12 V battery.

I need to know what is the relationship between output current & output voltage of buck converter? Do they follow the principle of Input Power = Output Power?

When we lower the output voltage using PWM, is the current suppose to rise in response to that?

A reference from some very reliable source or experimental results preferably Research Paper will be appreciated which should say that 'current rises when voltage at buck output is decreased'. Or any mathematical/graphical proof.

Thank you in advance

 

[BradtheRad]

Recent discussion about a similar topic:

https://www.edaboard.com/threads/326815/

The basic buck converter will not give you more current out of the inductor than goes into the inductor. However if you add a choke and capacitor at the input, you can draw a continual current from your PV panel (which is the maximum optimum usage). Then you send current pulses, at higher amplitude, to your battery. (A simulation of this is shown in the above thread.)

 

[D.A.(Tony)Stewart]

Keep in mind there are two requirements in MPT regulator.
1. Source voltage regulation, Vmp using series LC buck regulator near 80% of PV open cct. voltage Voc. Hunting for max VI makes small improvement.
2. Load profile for battery with Current limit and Voltage limit.
3. Vmp drops slightly with solar power. so may be 80+/-5% over Solar power range.