signal generator for ultrasonic welding

[meliharicii]

hi guys. i making ultrasonic welding machine. but my problem about signal generator. how is the make signal generator? i need the output 20kHz and  2000w. can you help me?
thanks

[LaserSteve]

Probably much easier to buy a recent Bronson Driver  on EBay and repair it.  You do need some sensing on the transducer end for system protection and tuning.

STEVE

[meliharicii]

20kHz and 2000W tell some of the information needed but not all.
(a) What is the voltage and current that is required at the output of the power supply?
(b) What is the waveform that is required at the output of the power suppy?  Are you trying to create a pure sine wave at 20kHz?
(c) Does the voltage and/or current (and power) at the output of the power supply have to be adjustable over a wide range?  What if you need only a much smaller amount of power than 2000W for a certain task?  Or will it almost always be using 2000W on or off for your needs?

Anyway for a power supply in that general power class a typical thing to do would be to:
(a) take AC mains voltage (e.g. 220VAC or whatever in your location)
(b) Run the AC mains voltage through a power factor correction module / circuit that generate enough power at DC in a voltage range such as near 380VDC.
(c) Take the approximately 380VDC voltage coming out of the PFC and apply it to a capacitor bank that can hold sufficient energy for your power supply and which filters / stabilizes the voltage somewhat.
(d) Have an protectively electrically isolated full bridge type DC-to-AC inverter circuit that takes the 380VDC range input voltage and generates a 20kHz sine wave (if that is what you want) at the voltage and current you require at the output.  There are standard full bridge type inverter circuits that perform this function.  The key parts are the bridge driving MOSFET circuit and a suitable transformer to change the voltage from the primary to the secondary.
(e) You will also need some appropriate amounts of filtering at the AC output of the inverter for EMI and spectral purity reasons, and whatever kinds of feedback / overload protection that may be required.

If you wished to operate the device off of a lower voltage such as the 48VDC output of another power supply instead of 380VDC from the AC mains then that could be done in a similar way.

i got it.
i need output 20khz sinus walve and nearly 2kW power.
have you got any circuit this subject?

[meliharicii]

Probably much easier to buy a recent Bronson Driver  on EBay and repair it.  You do need some sensing on the transducer end for system protection and tuning.

STEVE

thank you. can you send me link about bronson driver?

[richnormand]

You mean Branson ultrasonic welder stuff?

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR3.TRC2.A0.H0.Xbranson+ultrasonic+welder.TRS0&_nkw=branson+ultrasonic+welder&_sacat=0

[meliharicii]

You mean Branson ultrasonic welder stuff?

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR3.TRC2.A0.H0.Xbranson+ultrasonic+welder.TRS0&_nkw=branson+ultrasonic+welder&_sacat=0

thank you. but this is so expensive. already i want to make myself. this is so important for me. my problem about signal generator. i using icl8038
integrated.

[danadak]

The critical part of the design is NOT the sinewave generator, its the
2 KW inverter. This is a major design in terms of magnetics, layout,
timing, safe area of components. If you have never done any power
design before this a very challenging design to tackle.

I had the pleasure of calling on 3 very senior EEs that designed plasma
cutting and welding equipment over many years. Each visit was generally
a humbling experience.

There are ap notes at Ixsys, IR, ST, etc.. on high power inverters,
that would be a starting point.

Good luck.

Regards, Dana.

[Marco]

He can't afford not to be in resonance, the circuit needs to be resonant by design ... having to tune it all the time would be silly.

That said, it all seems a bit optimistic.

[meliharicii]

how is the make signal generator? i need the output 20kHz and  2000w.

thats no signal generator you are asking, thats the welding stuff itself. signal generator easy to build using some transistor or opamp oscillator https://en.wikipedia.org/wiki/Electronic_oscillator. but then how much voltage output you want? 2KW can be 200V * 10A, or 10V * 200A.

i got it. Output voltage and current very low. i have 20kHz sine wawe. but i dont have enough power.

[mikeselectricstuff]

It is highly unlikely you will be able to build one for less than you can buy something used unless you price your time extremely cheaply.
Ultrasonic transducers are complex loads, and will be far from trivial to drive.

[Marco]

i got it. Output voltage and current very low. i have 20kHz sine wawe. but i dont have enough power.

You'd need a full bridge driver at around 250V bus voltage to get 2 kW out of a 20 Ohm at resonance transducer ... assuming you drive it very near the resonant frequency (as I said, the system needs to be resonant by design).

PS. are these transducers meant to be driven with the rectified mains as the bus voltage, so with 100 Hz modulation, and no PFC/isolation? It seems to end up nearly correct power wise.

[meliharicii]

i got it. Output voltage and current very low. i have 20kHz sine wawe. but i dont have enough power.

You'd need a full bridge driver at around 250V bus voltage to get 2 kW out of a 20 Ohm at resonance transducer ... assuming you drive it very near the resonant frequency (as I said, the system needs to be resonant by design).

PS. are these transducers meant to be driven with the rectified mains as the bus voltage, so with 100 Hz modulation, and no PFC/isolation? It seems to end up nearly correct power wise.

did you mean this?

[mikeselectricstuff]

Sorry but if you don't understand why that would not be remotely suitable you have zero chance of making a 2kW supply work. Just go buy something, seriously.

[yli130]

Hi,

Did you make one finally?