Scope/Equipment Recommendation for Power Electronics (PE) Person  - Page 1
Forum section: electronics / testgear

author: Vancouver_Kid
author_rank: Newbie
timestamp: December 01, 2024, 09:04:01 pm
content: Hi All,I'm a PE who's starting to slowly build up my lab. I'm wanting a scope that is suited for PE applications (AC-DC or DC-DC). I'm not really familiar with all the scope brands out there so, with me giving some requirements/specifications I'm hoping the community can help suggest some options given:$1000 CAD top endI work with fundenmental frequencies of less than 500kHzWould like bode plotA high point count FFT (given the price range/class)Ability to get some power analysis tools12-bit ADCSerial/standard communication protocols, I2C, SPI, UART, USB, RS232/485, low speed stuff. No mipi buses here...I would like to be able to capture SiC/GaN transition times, but, that may be asking too much given the price limitation. Thoughts?Waveform capture rate, memory depth, sampling rate, I don't know what would be considered best in class these days given the price range but seeing some options would be greatSome suggestions for high voltage diff probes given the frequenciesThe stuff I work on will most likely be 450VDC or less, that number is being driven by PFC output spec'sWhat rogowski coils are people using for TO220's (between the legs)? orMy own research for scopes led to here:https://siglentna.com/digital-oscilloscopes/sds800x-hd-digital-storage-oscilloscope/It is very enticing to see the SDS804X HD and how it can be upgraded to the 200MHz version, although even when reading the instructions, I'm a bit confused. For $614 CAD and upgrading to a 200MHz version, the closest Rigol competitor I think would be the DHO924, but that's closer to $950 CAD. Would love to hear more of your opinions between the two given what I'm looking for and also the application. Features I haven't mentioned, etc.Looking forward to the help and chatting about some options.Cheers

author: tautech
author_rank: Super Contributor
timestamp: December 01, 2024, 10:59:48 pm
content: Quote from: Vancouver_Kid on December 01, 2024, 09:04:01 pmSound choice.A little on the PA option here:https://www.eevblog.com/forum/testgear/sds804x-hd-vs-sds814x-hd/msg5385836/#msg5385836

author: Martin72
author_rank: Super Contributor
timestamp: December 01, 2024, 11:03:32 pm
content: Hi,If screen size is not important, the SDS800 series would be perfect for you.Siglent's Bodeplot is very well implemented across all model series, and power analysis is also offered.For the PA, a differential probe and a suitable current clamp are still required.

author: Vancouver_Kid
author_rank: Newbie
timestamp: December 02, 2024, 12:12:01 am
content: Quote from: tautech on December 01, 2024, 10:59:48 pmHi, okay good to know I was on the right track. Those two scope brands are ones I'm familiar with, and then there's the more premium brands at work we all most likely use.What about these guys: GW Instek, Micsig, OwonI've seen/used some Micsig stuff and for PE's it can be helpful when you make the source the internal battery rather than wall plug, but I haven't really been able to narrow something down within my budget. Know of any models?GW instek and Owon I see pop up, but never met anyone who uses them so I have zero insight into whether there okay or not. Thoughts?

author: nctnico
author_rank: Super Contributor
timestamp: December 02, 2024, 12:20:58 am
content: GW Instek and Micsig make good equipment but not for bottom of the barrel prices. Typically their equipment just works as expected out of the box without needing endless firmware updates.Yokogawa seems to focus a lot on oscilloscopes for power electronics. But again, way outside your budget.Owon OTOH is a bottom the barrel brand which might be dissapointing. Oscilloscopes require complex firmware and need quite an investment in developing time & money to get it right.

author: tautech
author_rank: Super Contributor
timestamp: December 02, 2024, 12:26:51 am
content: Quote from: Vancouver_Kid on December 02, 2024, 12:12:01 amThat's the issue but with all the features you need SDS800X HD has the same as the higher priced Siglent models all the way to the 6 GHz SDS7000A.They share the same GUI which makes SDS800X HD models attractive as a cheap sounding board before investing in the $ $ models with more features.Don't underestimate these cheap little platforms.....

author: Vancouver_Kid
author_rank: Newbie
timestamp: December 03, 2024, 04:26:33 pm
content: Quote from: tautech on December 02, 2024, 12:26:51 amCould you use such a scope for doing pre-compliance say for FCC part 15B, for instance? You wouldn't be able to visualize anything related to quasi-peak, right? Is the AVG the same AVG on a spectrum analyzer? I've never really used FFT's on scopes before, so I don't know much about how they compare to an actual benchtop spectrum analyzer. Would be great if you could speak about whether you could get away with doing some pre-compliance work, say conducted EMI from a LISN? The lack of a 50ohm input I imagine would be an issue..

author: Smokey
author_rank: Super Contributor
timestamp: December 03, 2024, 06:00:29 pm
content: Quote from: Vancouver_Kid on December 01, 2024, 09:04:01 pmJust a heads up, "PE" is usually used to mean "Professional Engineer" as in the license.https://en.wikipedia.org/wiki/Regulation_and_licensure_in_engineeringI've never heard a power guy call himself a PE to refer to "power electronics person" (and I'm sort of a power electronics guy).

author: tautech
author_rank: Super Contributor
timestamp: December 03, 2024, 07:28:59 pm
content: Quote from: Vancouver_Kid on December 03, 2024, 04:26:33 pmNo.25 MHz max for SAG1021I.It doesn't pair with FFT like a TG in a SA.Many questions of how FFT works can be found in this thread:https://www.eevblog.com/forum/testgear/sds800x-hd-review-demonstration-thread/

author: Martin72
author_rank: Super Contributor
timestamp: December 03, 2024, 09:51:55 pm
content: Quote from: Vancouver_Kid on December 02, 2024, 12:12:01 amIf you couldn't spend much money, 10...15 years ago the cheap China brands were the only alternative to the well-known professional brands.Mention should be made of Hantek, Uni-T, Liliput Owon, Rigol, Siglent, GW Instek.At that time, they were a bit of a grab bag; sometimes the product was good, sometimes not, or mostly not.Time has passed and some have developed into respectable manufacturers.Others, on the other hand, are still providers of grab bags, presumably because they only resell and do not develop anything themselves.Personally, I would give Hantek, Owon and Uni-T a wide berth when it comes to oscilloscopes.Rigol and Siglent are now well-known manufacturers that, in addition to high-priced products, have not forgotten their “roots” and still offer affordable oscilloscopes.Whereby siglent has a clear advantage in terms of professionalism and support, even with the cheaper models.I think GW instek is an interesting brand.I only know them for frequency generators and milliohm meters, so I can't form an opinion about their scopes.The same applies to Micsig, a relatively young brand.I only know them for their probes and current clamps.That still works for them a bit like a grab bag.I can't say anything about their scopes, because, as with GW instek, I haven't been able to test any yet, and I don't say anything about them.

author: 1audio
author_rank: Frequent Contributor
timestamp: December 04, 2024, 03:17:26 am
content: If you are talking about power as in motor controls, variable speed drives etc. then you need something that will be safe to use around those. I would recomend a Tek THS720P or similar which can be had for a pretty reasonable pricehttps://www.ebay.com/itm/276708270659?_skw=ths720&itmmeta=01JE7TM4DXWT12V3NW1PRA3JSW&hash=item406d192243:g:L6oAAOSwWldjQpaO&itmprp=enc%3AAQAJAAAA4HoV3kP08IDx%2BKZ9MfhVJKkQqxdekFV%2F7Vnw4WxJ44ysTqN4zLskY6VzOFzgic8bmbLZCRq7RI9f3X71InPay62VQYlIMKpVjGPsp4gT9888VCKs3rcTDVm3MvD9yt83g6y1l79G6wHDnXTBsNjy2DXaQIgRROOzi1%2F0Hqnu9%2BAQpHzeHjlVIdSw1KvFjq00hkdqwthOOtCusUvSIVH8o5rMgFcL0ocmA8dxBfELu1KCZP2NHeMbjeTg5Qk%2Ferselh9yeb2PZLUlZjhytcEhm8D6iP32B7PduYRjKq%2FcTKCQ%7Ctkp%3ABFBMjsfQ-vFk.They have fully isolated inputs that you can hang on various phases safely and the P variant has other features useful for AC power like harmonic analysis. There is a thred here on how to convert a 720A to a 720P.LISN's are expensive even on eBay. More than a decent scope. Maybe you can build one but I'm not sure how to validate a DIY LISN. Precompliance involves a lot of stuff to check. Its facinating and interesting to do the measurements but probably not cost effective to get all the stuff. And time consuming if from eBay and hamfests.