Rectifier and smoothing capacitor design tool. - Page 1
Forum section: electronics / general

author: geggi1
author_rank: Frequent Contributor
timestamp: June 23, 2023, 11:24:27 am
content: Hi all!I'm looking for a design tool to help me designing a high current rectifier.The system is a 12 pulse rectifier with smoothing capacitors.Design current is 1700-1500A at 145V

author: trobbins
author_rank: Frequent Contributor
timestamp: June 23, 2023, 12:49:44 pm
content: You can make your own tool using something like MS Excel, and using the many reference books on-line. That's what I did 20 years ago, but it preferably integrates the SCR's and diodes and heatsinking you can access, and the type of transformers and chokes you can access, and what contoller/driver you can use, and what protection parts and settings are needed, and uses your experience on what the appropriate rectifier configuration would be for starters. You would need to confirm the ripple requirement, and what the operating environment would be. There is a lot to go into a commercial product, so hopefully you are not thinking of starting from scratch, as it took me quite a while and that was having access to more than 50 years of experience and projects for assistance.

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: June 23, 2023, 12:57:00 pm
content: Hi geggi1,its mainly for valve-rectifiers, but you can even model your own rectifier-diode:http://www.duncanamps.com/psud2/index.html

author: f4eru
author_rank: Super Contributor
timestamp: June 23, 2023, 01:24:04 pm
content: At that kind of high power, you'll probably run into Power factor problems with your electricity company, or with your generator.Why not get a proper sync rectifier ?Some motor inverters can be reconfigured as PFC inverters, or even regen inverter, for example @ omron :https://industrial.omron.eu/en/products/a1000https://industrial.omron.eu/en/products/q2ahttps://industrial.omron.eu/en/products/rx2

author: Siwastaja
author_rank: Super Contributor
timestamp: June 23, 2023, 01:35:27 pm
content: What's wrong with SPICE?

author: TimFox
author_rank: Super Contributor
timestamp: June 23, 2023, 01:59:12 pm
content: I believe PSUD2 is a user interface with a SPICE engine.I find it useful, so long as one estimates the no-load transformer voltage and effective secondary resistance (transformer manufacturers quote secondary voltage at rated load current).Specifically, it directly gives filter capacitor currents, rectifier voltage and current, DC voltages, and ripple voltages for either resistive load or current load on the DC output.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 23, 2023, 05:54:46 pm
content: Quote from: f4eru on June 23, 2023, 01:24:04 pmThey appear already aware of that -- notice "12 pulse".A 6-pulse rectifier already has quite good power factor, though poor current THD. 12-pulse rectifiers are not uncommon at such power levels for this reason.A passive harmonic filter might be quite reasonable to address the remainder, if needed?At the low voltage, I'd be more concerned about loss; PN junction diodes will lose about a volt. A FWCT connection will be desirable (so, 6 taps per transformer * 2 transformers (to get the delta-wye 30° phase shift), with 12 diodes, into one common DC rail), which should be in the 99% efficiency range, for the rectifier alone at least, less transformers and related components of course. I would think a cap-input filter is not necessary, but perhaps a hybrid LC filter (where both reactances are significant for various harmonics) might be used to tune the current THD further; an LC filter can be used to further smooth the DC output if needed.Tim