Doubt regarding battery and boost converter

I have little doubt about supercapacitor and the boost converter.I have tried a simulink ,where supercapacitor supplies a variable load for few seconds through a boost converter.While running the simulation, supercapacitor voltage drops.But even when the SC voltahge drops,load terminal voltage remains constant.How is it possible?actually load terminal voltage should also drop isn't it?but for me it remains constant.Can anyone please explain it?

[SHALINI R]

Its supercapacitor, not battery

[Sabin]

A model would help us understand better the problem.