Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
I figured it out, my deadtime was set too high. I had it past the maximum set in the datasheet that why it was giving funny results at higher voltages.
Also I measured the upper gate signal on the oscilloscope and I'm getting a signal that has a duty ratio of about 3% three times in a cycle
---------- Post added at 02:30 ---------- Previous post was at 02:29 ----------
hence my output current waveform decreases as soon as I reach 50+ V...
cannot at the moment will post later today. At one point the PWM pin on the PIC stopped working when I pushed the system up to 230 V
---------- Post added at 23:05 ---------- Previous post was at 23:02 ----------
could possibly be a fault with my bootstrap circuit. but i built it with the...
good day everyone
I'm having a problem not exactly sure what the cause is but I suspect its ground plane noise. I'm using a PIC to generate a PWM signal to my power circuit at about 60 kHz. Whenever I push the input voltage past 50 - 60 V the system doesnt switch properly. up until 50 V it...
Thanks. So I'll try removing the snubber caps tomorrow and check if it's stable. Anything else I should check incase removing those snubber caps don't make any difference? Should I increase my deadtime between the gate signals just to be safe?
Ok Thanks. Think it will be better to just remove them from my circuit. Also, from my switch current and voltage waveforms how will I be able to see if I'm getting ZVS/ZCS? And what size cap should I use as my filter?
I've added the circuit diagram in pdf. The resonant capacitors are 680nF, input capacitor is 2.2uF, snubber capacitor is 47nF, the inductance is 22uH and the resistance is around 2 ohms (according to my calculations). when i set the switching frequency to 28kHz at around 50V the output current...
Thanks for the quick reply mtwieg, the igbts do get a bit hot but I have them on a massive heatsink. I set the deadtime to about 4us incase the igbts are slow. The cap is just to filter the transients so I dont get huge spikes over my igbts.
---------- Post added at 12:23 ---------- Previous...
Good Day Everyone
I'm making a half bridge resonant inverter, I'm using the AC line voltage which is rectified and filtered with a 2.2uF cap. The problem is, whenever I push the AC voltage above 100V (I'm using a variac to control the voltage) it seems as if the IGBTs cross conduct causing a...
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
