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eonscom
03-04-2019, 06:16 AM
Hi
I am going to make smps to apply to vacuum tube amplifiers.
So far, the sg3525 and ir2110 have been used to produce more than 450V 1A, but there are many defects.
I want to hear advice from an expert.

eonscom
03-04-2019, 03:54 PM
This is the schematic I made.
Check if there is a problem with the circuit.

eonscom
03-04-2019, 04:14 PM
The problem seems to be that the high frequency is distorted by the fine noise coming out of the output
6890

Silvio
03-04-2019, 08:18 PM
This is the schematic I made.
Check if there is a problem with the circuit.

Do you intend to regulate the output voltage?
Did you check the dead time on the gates?
What current draw is there on the HV output?
What is the value of the output inductor?

eonscom
03-05-2019, 04:28 AM
The output voltage only applies to rectified
I am looking for a way to adjust the voltage

There is enough dead time.
I applied a 100 ohm resistor and there was no problem when viewed on a scope

Not HV
It is the power to heat HT tube heater
Without vacuuming the tube heater power to dc
Directly apply high-frequency power to heat

It was manually wound on the ring core
I do not know exactly what Henry is.
See photos
68916892

Silvio
03-05-2019, 06:20 AM
If your maximum current lies on the tube heaters then you can sample the output voltage there. You can rectify the voltage only for sample. you can still feed the heater AC.

The output inductor value is chosen according to the current it is going to handle. If the current is small then the value of the inductor rises.

A feedback loop can be done with the heater voltage and regulate the pulse width to stabilize the output voltage.

Something about the circuit. I see no snubber on the primary of the transformer. How pure are your wave forms at load?

eonscom
03-11-2019, 08:19 AM
The problem is the transformer.
Bifilar winding of coil to rectify by center tap method
I changed the end and made the final.
Even though there is no load, the coil gets hot.
I do not know what went wrong.

Applied Trans: ETD49
Primary: 0.45mm X 5 - 22 TURN
Secondary: 0.32mm X 2 X 2 - 70 TURN : 450 V expected

Silvio
03-11-2019, 11:32 PM
Be very careful when winding the secondary. Do not forget that a square wave tend to have a lot of harmonics and also tend to generate spikes. Spikes can also lead to high voltages and can be multiplied in the secondary windings by the turns ratio. (high voltage can arc and destroy the insulation and thus having shorted turns)
In your case this must be the cause of the secondary winding heating up.

Turns ratio look good and at 220vac you should have around 490v on the secondary when smoothed with the output capacitor. ( if you have spikes in the primary this can rise to over a 1000v)

I suggest:-

1) You insert a snubber across the primary winding this will suppress any spikes as the mosfet switches off.

2) Post a scope shot of the waveform across the primary winding.

3) Read this blog post and download the PDF. You will learn about winding practices.
The link is here http://www.diysmps.com/forums/entry.php?143-Transformer-winding-practices-for-smps

4) Rewind your transformer in the way explained by the PDF file.

5) It will help a lot if you leave some space on the bobbin cheeks with the winding. Put a layer of Maylar tape between each winding layer.

6) Take measurement of the input current and let me know what is it, If you have a watt meter it is better.

MicrosiM
03-12-2019, 10:16 AM
Generating that number of output voltages with that PCB is a huge challenge.

I also don't understand your idea behind the variable output voltages, i don't see a regulator.

I think more work is needed to achieve your goal

eonscom
03-13-2019, 07:43 AM
The current image smps is rectified to about 315v and is used as the B + voltage of the tube amplifier
HER 508 4 diodes are used by bridge rectification.

Applied Trans: ETD49
Primary: 0.85mm X 1 - 40 TURN
Secondary: 0.32mm X 3 - 86 TURN : 315 V

When applied to the above specifications, the output waveform has a lot of ringing and noise.

I am making a new transformer to apply the center tap method.

Excellent -SMPS Transfomer Tool Data
6896

Silvio
03-13-2019, 10:53 PM
The current image smps is rectified to about 315v and is used as the B + voltage of the tube amplifier
HER 508 4 diodes are used by bridge rectification.

Applied Trans: ETD49
Primary: 0.85mm X 1 - 40 TURN
Secondary: 0.32mm X 3 - 86 TURN : 315 V

When applied to the above specifications, the output waveform has a lot of ringing and noise.

I am making a new transformer to apply the center tap method.

Excellent -SMPS Transfomer Tool Data
6896

Probe the primary winding. and see if the ringing is present at the primary. If it is there then you have to put a 470pf cap in series with a 3 watt 47 ohm resistor across the primary to suppress spikes and ringing.

The pictures you posted of the tool data is too small to see it. Take picture with mobile or camera of computer screen and upload that.

The primary of the transformer turns seems a little too much. I do not know your switching frequency and also the core material. Please give the details and I will help you out with your calculation.

1 core material
2 switching frequency
3 input ac voltage at your house
4 heater voltage and current
5 Max plate DC voltage
6 Bias maximum DC voltage

eonscom
03-14-2019, 05:59 AM
1 core material

-I do not know the exact specifications.
But size is the same (etd49)


2 switching frequency

- 50kHz (variable) 30~80Khz

3 input ac voltage at your house

AC 215 V

4 heater voltage and current

300B : 5V 1.5A X 2EA : #18 WIRE 2TURN (6.7V Down by resistance)
6SN7 : 6.3V 0.5A X 2EA : #18 WIRE 2 TURN

50KHz AC DIRECT HEATING

5 Max plate DC voltage

MAX : 420V

6 Bias maximum DC voltage

MAX : 90V

Silvio
03-14-2019, 10:05 AM
Hi Eonscom, I have made some calculations for you. As for the core material I chose N27 which is not so high permeability as the core you are using is not known.

Here are the results

Note 1)
Wire size is 0.5mm This wire can handle the frequency of 60Khz. If you make thicker wire it will be in vain as the current tend to travel on the outer skin at high frequencies and the extra thickness will not be used. However you can use multiple wires together (twisted or side by side) In your case 3 wires by 0.5mm for the primary. Choose the best fit for a single layer. Either 3 wires side by side or 3 wires twisted together.

Note 2)
See if you can sandwich the secondary windings between the primary. Make half primary turns then secondary turns then half primary on top. Leave the heater windings for last on the very top. That is on top of the last primary winding. the heater windings are not so important.

Note 3)
Try to cover the whole bobin with each layer of winding. Leave 3mm margin space at the ends of the bobbin for safety. Use mylar tape this tape is high temperature and very thin. Use 3 layer of this tape to isolate the primary winding from the secondary. Use one layer of tape between each secondary winding layer so that you can see better what you are doing.

Note 4)
The voltages used are made such as the amplitude of the rectified and smoothed voltage will rise to the peak. If you notice the 2nd picture you will see what Mean. Please also note that the voltage will sag down with load as the smps is not regulated.

Switching frequency 60Khz

Primary turns 22 turns (3 wires X 0.5mm)

Plate secondary voltage turns 65. (0.5mm x 1) ( peak voltage 427v at 215vac input)

bluetooth aux 15-0-15 3+3 turns (0.5mm X 1) use 2 wires together and start from center tap. put ends on each side on pins.

Bias voltage 13 turns (0.3 x1) Peak voltage 85v at 215vac input

Heater voltage 2 turns (6.3v) 0.5mm X 1

Heater voltage 2 turns (5v) 0.5 mm X 2

Silvio
03-14-2019, 01:42 PM
Hi Eonscom,
One last note if you want to make adjustment just calculate that you have 7 volts per turn. 155v / 22 turns pri =7v per turn

eonscom
03-14-2019, 02:40 PM
Thank you for your quick reply.
The above specs were first attempted and have problems.
Currently in production
The problem is trying to apply the center tap method rather than the bridge rectification method

Primary: (0.45x5) x 22 turn
Secondary: # 18wirre 1 turn: Normal output waveform (6.73V)
It is confirmed to be normal for testing

There is no problem in applying 420V winding to 80 turns
Further winding of 80turn will cause the coil to heat up even though there is no load
test: # 18 Wire 1turn: Output Waveform Distortion (5.8V)

6898
6899

eonscom
03-14-2019, 02:58 PM
Re-upload your photo
6900

Silvio
03-15-2019, 06:36 AM
Thank you for your quick reply.
The above specs were first attempted and have problems.
Currently in production
The problem is trying to apply the center tap method rather than the bridge rectification method

Primary: (0.45x5) x 22 turn
Secondary: # 18wirre 1 turn: Normal output waveform (6.73V)
It is confirmed to be normal for testing

There is no problem in applying 420V winding to 80 turns
Further winding of 80turn will cause the coil to heat up even though there is no load
test: # 18 Wire 1turn: Output Waveform Distortion (5.8V)

6898
6899

Regarding rectification well the bridge requires one winding while center tap requires two windings.

One tip for you if you want to make a center tap winding.
wind two wires at the same time. You start at the center tap. you finish with two wires each wire will be a separate winding.
This method will help to have balance windings with equal voltages.

I do not recommend that you make center tap winding for the high voltage side, It is the way you are winding it. Leave margin space at the ends like 4mm on each side and put a layer of tape between each layer of winding. Do not use masking tape it is not good for this work.

Remember that square wave tend to have spikes and easily breaks insulation at high voltage.

The distortion in the waveform is intermittent and not constant. try to twist the ends of the one turn loop and measure again

Silvio
03-15-2019, 06:50 AM
Re-upload your photo
6900

May I ask where are you going to take the sample voltage for the regulation of the output voltage?
I see you opted yes for regulation in Excellent IT software

Remember that the software is suggesting the inductor value. This value will grow with minimum current for each winding. the lower the higher the inductance. If the plate voltage has a constant load then it will be right to put the right current in the software. Please note that if you are not regulating the output you do not need the inductor or it could be very small.

The snubber resistor you are using is too high. Try like 100 ohms at least, or lower. It could be down to 10 ohms

read this article about snubber. download the pdf.

http://www.diysmps.com/forums/entry.php?147-Calculation-of-snubber-components-and-driver-gate-resistors

eonscom
05-14-2019, 04:16 AM
I tried it. However, when I switched on, the protective 100W bulb turned on because of the overcurrent.
I have wound several windings, but more than 400v (only 64 turn) is not a problem with single windings.
If you turn 128 times in center tap mode, the coil is very hot even if there is no load.

eonscom
05-14-2019, 04:38 AM
I've tried a few, but the best way is
The windings are divided into two areas.

Silvio
05-14-2019, 04:59 AM
Have you tried winding the 64 turn in bifilar fashion? Are you using a layer of tape between each winding. Are you leaving 4mm margin space at the bobbin cheeks? I think your winding is arching and shorting out due to the high voltage.

Are you using a snubber in the primary? any spikes in the primary will be amplified in the secondary winding and the voltage here may rise more than a 1000v. If your insulation is not correct the secondary winding may arc and short out.

When trying out the transformer put a small load on the output. This will help control any excess voltage spikes generating very high voltages. Try to never start the transformer with the secondary high voltage open.

Lastly use new enameled copper wire. see that it is in good condition. Use mylar tape for insulation and not something else.

Good luck

eonscom
05-14-2019, 06:32 AM
I did not know if I needed to put a small load on the high voltage secondary test.
I would like to adjust one more output voltage.
We expected the output voltage to change when the input voltage of PWM changed, but it did not change much
I want to know how to change the secondary voltage.

Silvio
05-15-2019, 12:23 AM
If you are opting for regulation keep in mind that this is done in the primary winding. If you have more than one secondary than all the secondary voltages vary together. Having such a high output voltage it would be some what difficult in a way to control from the high to the low voltage as the margin of error will be quite large due to that the control voltage will be more or less 2.5v and the output being around 400v.

I guess you have to choose another winding with a lower voltage to do this. You will have to use an output inductor with the winding that is being sensed. This is important otherwise it will not regulate properly. You must also have a minimum load with the output when using regulation.

If you are expecting the output to change you must load it a little so that the excess charge on the capacitors will fall down accordingly. If you are still getting a higher voltage than needed than you have to adjust the winding turns. You can use the formula

155v / primary turns = volt per turn. Here you will be close to the wanted voltage.

Regards

eonscom
05-16-2019, 04:37 PM
I am trying to adjust the secondary voltage.
Even in normal smps, there is VR for fine tuning
Try to vary the voltage by about 10 to 20%

eonscom
05-17-2019, 08:06 AM
This is an OTL tube amp.
The secondary voltage is 150V, -150V.
Change this voltage.
Adjusting the voltage of the sg3525 no1 pin changes the PWM pulse width.

When the pulse width changes, the voltage must also change accordingly, but it does not change much.
I want to know how the voltage is controlled.

694369456944

Silvio
05-18-2019, 05:57 AM
I can see you make a nice job there. I would rather see some oscilloscope shots showing how the pulse width is changing.
The voltage is controlled by changing the pulse width. However the output must be loaded to see the voltage change. A narrow pulse will give a low voltage and a wider pulse will give higher voltage.

We like to see a schematic of your setup to see what you actually did. You can draw it up by hand and take a photo of it.

eonscom
05-29-2019, 09:08 AM
GATE Pulse PWM control by varying width
The output voltage is almost unchanged.

Yellow is GATE PULSE
Light blue is output

Silvio
05-29-2019, 07:46 PM
Do you have a load on the output? Without it the output voltage never changes.

eonscom
05-30-2019, 02:49 PM
connect Load does not change the voltage

The voltage changes only when the waveform begins to distort

Silvio
05-30-2019, 08:42 PM
The output voltage will change with a narrow pulse width if it is loaded enough. It seems that the output is still holding the peak voltage by the output capacitor. Remember that every time the transistors switch the primary winding it is always the full voltage. If the output is loaded correctly then the voltage should get lower with a narrow pulse. I hope your feedback is sensing the voltage you are measuring.

One other option for you is to increase the inductance of the output inductor if the load is very small. You can also reduce the value of the output capacitor.

PS We never saw your schematic diagram please post it if you want help as I am blind folded what you actually did.

eonscom
05-31-2019, 05:17 PM
first time i upload Schematic

Silvio
06-03-2019, 08:19 PM
I see the schematic now, well there is no true feedback and the output is not sensed for voltage. You only have a means of changing the pulse width with a preset. As the load changes so does the pulse width need to change to maintain regulation of the output voltage. In your case the output is not sensed.

Regarding your circuit you said that the waveform tend to change when the voltage on the output starts going down. First of all you must check the waveform on the output of the IR2110 and not the output of the sg3525. The input of the IR2110 is logic and if the waveform on the sg3525 is disturbed a little the output waveform will still be nice and square. What is arriving at the gates is most important.

If you want to find a compromise with your circuit you must load the heater output and also mimic the plate load otherwise there will be no change in output voltage. I already told you, you must have a load on the output. Do not try without it. You can try to load with 2 or 3 bulbs of 15w/220v in series to load the output. This will load the output to around 5w to 8w. Your output inductor must be around 300uH on each leg. The windings must be one opposing the other which means one is wound clockwise and the other anticlockwise if they are on the same former. If on separate former it does not matter which way you wind them.

I hope this helps

6961