Nothing energy from the second pulse will be stored, unless it's voltage is greater than the voltage already at the capacitor. So the only way to harvest energy from the second pulse is to either make it larger, or make the cap voltage from the first pulse lower than the second.
You might try using an inductor circuit like a buck converter.
The cathode of two diodes is connected to the inductor, and should be schottky.Code:-------D1----------L1----------- | | D2 C1 | | gnd gnd
No guarantees, but this might give you some improvement.
Please give me some explanation about this circuit?