DC-AC board PCB review - Page 1
Forum section: electronics / projects

author: analityk
author_rank: Regular Contributor
timestamp: January 13, 2025, 10:03:16 am
content: Hi all,im working on my own domestic project, for educational (my education) purpose and i will show you my board. I know there is some more experienced power engineeres and you can give me some valuable feedback. In future i want relese all of my works in open source (free, not for fee) project (hw and sw) so there is some reason why your feedback is important.Some comments for project:this PCB will be part of induction heater system, it will delivery AC currents for resonant transformer. My goal is reach to 15 A drawing from source and maybe in far future work up to 400 V DC, but overal power will be close to 1 kW;desired frequency is between 100 and 200 kHz, ZVS;Q1 to Q5 is point to discusion, today in my prototype system i have C3M0120090D but in 8 A rms drawing from source (at 60 V) there is some serious power looses, i gues due to 0.12 ohm channel resistance (and there is two in series because it is full bridge configuration) and there is Last Time Buy status for this SiCs. I think about C3M0025065D;DC-DC brick for turn on/off transistor like here is tested by me and it work well (especially for two back to back mosfets using to high inrush current DC load);Sincerely

author: shabaz
author_rank: Frequent Contributor
timestamp: January 13, 2025, 11:58:55 am
content: I'm not a power engineer so please don't trust my comments entirely, but personally, I would change things. Here's some comments/questions, consider them like check-boxes to rule in/out for yourself:Where's all the driver circuitry? That's a key component of the system and it's missing.What happens if a connector is accidentally disconnected or works loose? Will the inputs be floating?Why is this not a 4-layer board? You've got little loops for paths for all the gate inputs.Are you sure the internal diodes are sufficient?Maybe it would be good to consider additional smaller capacitance, say several ceramics in parallel, rather than just use those large electrolytics.

author: analityk
author_rank: Regular Contributor
timestamp: January 13, 2025, 12:40:20 pm
content: 1. The driver circuit will be localised close to this board and connected by cables and goldpins. I want to have all controll electronic on one board and power side on this one. Currently mosfet drivers are as far as 2-3 inch from mosfets. In new design this distance can be reduced.Spliting power and controll board is always good idea in my opinion. Ofc there are some limits, i think about using HEMT transistor and it seems to be imposible to drive them in this manner.2. I can not see room for improvement by 4 or 6 layer design. Rather i should convert some track to pad and remove soldermask from them but again i think this board are no so demandig. But here my point of view can be wrong.3. I do not understand question about internal diodes. SiC internal diodes are good enough for achive zvs but there is also task for controller to watch on currents in circuit and set up right frequency. Also leakage inductance value is important.4. This is good adivce...

author: analityk
author_rank: Regular Contributor
timestamp: January 13, 2025, 01:05:53 pm
content: I placed 2 x FG23C0G2J104JRT00 -> 100 nF, 630 V, C0G caps instead of one hole for mounting.Add photo with actual state, it work.