I am working on a DC-DC converter for a DC microgrid. In MATLAB simulation for reducing the ripple content, 48 Volt DC bus gets stable with a very large capacitor ranging from 35 F to 40 Farad. is it suitable to use such a high capacitance value capacitor? your suggestions and feed back will be highly appreciated . Thanks
Go through this website, you may find it useful for your case.
https://www.specterengineering.com/blog/2019/9/7/dc-link-capacitor-selection-for-your-inverter
Hi, Qudrat Ullah
This paper may help you:
https://www.cde.com/resources/technical-papers/Selecting-and-applying-DC-Link-bus-capacitors-for-inverter-applications-09-30-20a-1.pdf
Absolutely not! Your values of 30F are quite astronomical! You CAN get super capacitors around 4F but they tend to be low voltage and will be VERY expensive. Typical long life ceramic capacitors used in DC-DC applications have values around 10uF. I would look very critically at redesigning your system, or seeing if there is something wrong with it. Capacitors are really only used for current ripple at high frequencies.
If it is not possible you COULD consider using a battery bank instead, Lithium Titanate battery technology could give you a similar high charge discharge rate.
If you can explain a little more about your system I might be able to give you some more pointers.
The appropriate answer: it depends.
The basic considerations:
- What's the energy source and what is the source's behavior over time?
- What's the (nominal, maximal) output power ?
A rule of thumb (basically derived from DC powered from the 50 Hz grid through a transformer) would be 1000 µF per A load current. Anything beyond that is not really reasonable unless your power input is AC of a very low frequency.
With the remaining ripple you have to live. If you need a lower-ripple supply, consider some buck or boost DC/DC converter separating the low-ripple output from the DC rail.
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