Warning: Creating default object from empty value in /homepages/11/d132647312/htdocs/Amfone/mkportal/include/SMF/smf_out.php on line 47
Board for Nigel's PWM Power Circuit




 
The AM Forum
September 19, 2019, 09:54:29 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: Board for Nigel's PWM Power Circuit  (Read 328 times)
0 Members and 1 Guest are viewing this topic.
N4LTA
Contributing
Member
*
Offline Offline

Posts: 764


« on: August 18, 2019, 04:44:21 PM »

I built a board using Nigel's PWM modulator circuit. I haven't soldered in the power FETs as I have ordered some better FETs per Nigels comments. ( IRFB4227 FETs)

The PWM Modulator will use a 160 volt power supply with the power transformer rated at 1500 KVA

Hope to start testing this week as soon as I get a PWM generator up and running. I have some 1/8" copper bar to mount the FETS on as a spreader for the heat sink. I really don't expect much heat.

N4LTA


* pwm pwr board1.jpg (82.98 KB, 640x480 - viewed 58 times.)

* pwmpwr2.jpg (91.64 KB, 640x480 - viewed 49 times.)
Logged
vk3alk
Member

Offline Offline

Posts: 60


« Reply #1 on: August 18, 2019, 11:27:43 PM »

Hi Hugh

All looks good...... Smiley
Thought I would reply as there was none on your last post a few days ago....
My only advise would be to use a low ESR capacitor in the charge pump area .... pins 6 & 5....nothing but squarewaves there...
This might be interesting reading
https://www.avnet.com/wps/portal/abacus/resources/engineers-insight/article/understanding-esr-in-electrolytic-capacitors/
Also for the fast diode use a known one say from mouser / digikey
Avoid ones from China as a while ago now the ones I ordered were fakes and it blow up destroying extra components....etc:

For the heatsink the photo attached could give you some ideas...its not a PWM but a switcher .....

Only some thoughts thats all.....


Wayne

PS:  found it important to ground the heatsink assembly from my experience anyway.....





* P1030130.JPG (500.92 KB, 1600x1200 - viewed 40 times.)
Logged
N4LTA
Contributing
Member
*
Offline Offline

Posts: 764


« Reply #2 on: August 19, 2019, 10:02:32 AM »

Wayne,

Thanks for the advice. The FRED is a uN4007 from Newark so I should be OK there.

Not sure how good the cap is in the charge pump area. I have some better quality tantalum capacitors. I may change that one.

Appreciate the help.

Pat
N4LTA





Logged
vk3alk
Member

Offline Offline

Posts: 60


« Reply #3 on: August 19, 2019, 06:25:38 PM »

Hi Hugh...

I would stick to a new 100uF low ESR electrolytic capacitor......

That area of the circuit is important as the top FET does most of the work and needs to be hard ON and OFF if you get what I mean...
uF4007 will be Ok but I now use the BYV26C diode...
They have the same specs but are physically bigger.....will post a photo of both .....

Have now attached photo showing the difference between them....


Wayne


* uF4007 BYV26C.JPG (478.08 KB, 1600x1200 - viewed 27 times.)
Logged
N4LTA
Contributing
Member
*
Offline Offline

Posts: 764


« Reply #4 on: August 19, 2019, 08:55:21 PM »

I ordered a couple of low ESR Caps today along with a few of the AVX caps mentioned in the article you suggested.

I am also looking for a typical class D output transformer circuit. I have built them with transmission line type transformers for low frequency but would rather
use conventional transformers.

Some photos on this website (Nigels)  have dual windings but the actual connection is difficult to see. The enamelled winding tie together on one end but the other end is difficult to see.

Same for the plastic insulated winding. I have not seen these shown in any schematic. Can someone describe it or sketch a diagram?




Pat
N4LTA
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.045 seconds with 18 queries.