Guru
Joined: 13/10/2014
Location: AustraliaPosts: 1846
| Posted: 02:17am 26 Dec 2022 |
Thanks for that tip, I've decided to try them, hopefully I'll have the same experience. Just ordered the HY devices. Most main stream CAP suppliers are out of Stock, however earlier today I found some on RS - took 2 hours of trolling though all of them to find some in stock. So I have spares to play with and destroy on a test inverter.
Now I can blow Caps and FETS up like the Pros.
Also, thanks to all for the reply's
I tend to keep questions simple and details short so I sometimes comes across a little vague.
Soft start: Obviously inverters need an initial soft start due to the inrush current of the caps. I automated that with this HF inverter and that will be carried across to the new inverter.
The HF inverter also soft starts the AC output, not what I want, however, instead of modifying it and switching that off, I again made a controller so that the Load is not connected to the inverter until it's fully running. That will also be carried across as it's external to any inverter.
Fully understand the reasons to soft start the Toriod itself.
I hate giving background info, but in this case it might help with my questions. I've worked with High Current AC, DC and Very High Current LV DC, high power RF and worked in industrial electronics most of my life, including industrial micro-controller programming, forgotten a lot of it as in, use it or loose it.
The soft start question came up because there were discussions of specifically purchasing Manual AC ramp-up devices (manual soft start) for heavy induction loads in some discussion on these LF inverters, and that seemed to be a strange path to take.
My current Solar system started out as a basic emergency supply to keep a small fridge freezer going and run a mains pressure water pump when needed. There were not many low cost 48v inverters around at the time so I went with 24V, when looking for a low cost solar charger I made sure it could handle 48V as well. I have 4 of these, I'm able to split battery banks and controllers should one part of the system fail (redundancy - I can see whats coming - My eyes are open).
This 24v system will soon to be rewired for 48V - when I get the inverter running. I have 26kW of battery, so short term Load current is not a problem. Like most people, our average load is around 300w to 600 watts, with short periods of 1kW or 2kW. But I need to start that 3HP Dust Extractor.
While 2.5Hp might be easy for most inverters, it's not when there are things like 60Kg of large diameter flywheel on the end of the shaft. The HP rating is not an indication of the stall current and the time that current is needed to bring up the rotational speed for the current to drop off. The 3HP extractor draws low current once it's spinning, but takes over 55A @ 240V to get that lump of steel hanging off the shaft moving.
I love the idea of making it impossible for the the HI/LO side to conduct out of sequence and having dead time incorporated in the circuit. Using galvanic isolation between the control and Power PCB and bridge drive via 2 opto couplers "Warp" style parallel inverse driven to ensure each side cannot be commanded upper and lower on at the same time. This I believe was used / partly designed by wiseguy
So I'm still a few weeks from starting on the transformers and I also note that the thoughts on winding turns and ratio has shifted a little (or is that settled / converged) as more understanding of feeding and caring for your Toriod has evolved.
There is such great real world testing and effort put in by members of this Forum (and across other forums as well) and there is only so much information one can take in after weeks of reading every word of these, some fault finding posts are almost like a mystery novel, I was compelled to read to the end and find out "who done it".
Again thanks for any input, I find as I get older there are occasional senior moments, (the drugs will do that to you) fortunately got off those as fast as I could, much to the dismay of the Doctors - Well, tough, get over it.
Mike.
Edited 2022-12-26 13:13 by KeepIS