Got a stupid idea, has anyone tried using a function generator or sine wave generator set to 50 or 60Hz, (powered by 12V battery, either DIY or off the shelf), pass through MOSFET for higher current, and step up transformer (eg. 12V to 110/230V) to achieve a pure sive wave DC-AC inverter, 110/230V...approx 1 to 3Arms?
Yes , a lot !
That have been done also with tube on 1940...1960 !!
Nothing new , nothing remain to be discovered ...
Be aware!
This might be the lousiest way of powering audio equipment.
Noise is the problem, a DC/AC inverter creates thousands of times more noise than you will ever find in your wall outlet.
So if it isn´t for use far out in gods nature, try something else.
This might be the lousiest way of powering audio equipment.
Noise is the problem, a DC/AC inverter creates thousands of times more noise than you will ever find in your wall outlet.
So if it isn´t for use far out in gods nature, try something else.
I looked into it years ago and decided it was a total waste of time. Just use a car amplifier.
Kurt, what he wants to do won't have a noise problem as he's trying to use a low frequency sine wave not SMPS.
Kurt, what he wants to do won't have a noise problem as he's trying to use a low frequency sine wave not SMPS.
yeah...i guess it's 50/60Hz supply, shouldn't have noise problem....isn't it?
And, possibly a project for 300Vac power supply for tube
richie00boy....why you said it's a waste of time?
And, possibly a project for 300Vac power supply for tube
richie00boy....why you said it's a waste of time?
Because you need a huge transformer and big powerful stage to drive it, together costing at least as much as another amplifier. If your aim is to run an amplifier, it's far better easier and cheaper to just use an automotive amplifier.
Yes it can be done !
Frequency Generator(XR2206) + Class D Amp(Naturally it's mosfet based) + Output boost Trafo = Pure sine wave (Green energy except for trafo losses)
Frequency Generator(XR2206) + Class D Amp(Naturally it's mosfet based) + Output boost Trafo = Pure sine wave (Green energy except for trafo losses)
this configuration is very old, u will find most of the UPS systems in INDIA using such configuration in inverter stage, the transformer is normal 50Hz type..uses mosfets / IGBT output stage...IR2110 in each arm in a bridge configuration
have seen such a circuit in some old radio magazine...two mosfets driving a center tapped transf..the mosfets r buffered and phase inversed by quad op amps (LM324) the osc stage is a function generator XR22** i don't remember the number.
Power inverters can be clasified as to how close the output is to a true sine wave. Most inverters simply output a square wave. Others do a stairstep. Some do a pure sine wave. But a better way to make a good sine wave is the "class D" amp. This can be over 90% efficient. Also the function generator has one big problem: How to keep it running at exactly 60Hz. With the class-D idea you can use a digital "function generator" driven by a crystal controlled oscillator. But I think you have it right. All power inverters are just a function generator driving an amp. It's just that you picked a very in-efficient kind of amp
WHY do you need this? If the point is to feed a transformer that wants mains power on the primary then you can save a LOT of parts, power and money and do the conversion in just one step.
For example lets say you have 12VDC and need 400 VDC for a B+ supply on a tube amp. The cheapest way is to "chop" the 12 VDC at high frequency, above the audio range and send that to a 12:400 transformer. You will find that (1) you can use a very much smaller transformer for 50KHz then you'd need for 60Hz and (2) The caps and choke on the filter after the rectifier can be much smaller. And of course (3) there could be no 60Hz "hum".
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Hola Y'all....
I have been cogitating on a similar vein, looking to build a whole house UPS.
That being said most ups do not supply a pure sine wave more approximating a truncated sine which is ok for most small appliances however as I understand is not good for refridgerator compressors and the like . I think a scalable precision power inverter could be DIY but would require more brains than I can Contribute.
Any constructive thoughts are welcome.
Regards, Elwood
I have been cogitating on a similar vein, looking to build a whole house UPS.
That being said most ups do not supply a pure sine wave more approximating a truncated sine which is ok for most small appliances however as I understand is not good for refridgerator compressors and the like . I think a scalable precision power inverter could be DIY but would require more brains than I can Contribute.
Any constructive thoughts are welcome.
Regards, Elwood
I remember reading that a sine wave is not always optimal for motors, the optimal waveform depending on the motor itself as well as the characteristics of the load. The algorithms for controlling motors can be very complex.
If you want to learn more about motor control inverters, study EV inverters. They're probably the biggest inverters you'll come across.
For electronics (anything that rectifies the incoming AC to DC), a filtered square wave would be more optimal than a sine wave since the input capacitors would have a slightly higher average voltage and much lower peak currents. Most (but not all) will also run on DC.
Resistive loads (heating elements and halogen/incandescent lamps) only care about the RMS voltage. That's why they are very well suited to phase angle control.
Of course, if your load consists of several different types, you'll need to compromise.
If you want to learn more about motor control inverters, study EV inverters. They're probably the biggest inverters you'll come across.
For electronics (anything that rectifies the incoming AC to DC), a filtered square wave would be more optimal than a sine wave since the input capacitors would have a slightly higher average voltage and much lower peak currents. Most (but not all) will also run on DC.
Resistive loads (heating elements and halogen/incandescent lamps) only care about the RMS voltage. That's why they are very well suited to phase angle control.
Of course, if your load consists of several different types, you'll need to compromise.
The way to go is NOT to build a whole home pure sine wave system. Build a DC distribution system first. That is a small DC pannel with some big fuses or circuit breakers. Then each DC branch circuit drives one AC inverter. This is more complex but over all lower cost and will make you battery bank last longer because you will be able to match the inverter to the load.
systems like this a common on larger boats. A common set-up would be to have a DC bus and then a few (two) battery banks that can be switched on on or off the bus and a few charging systems that can also be switched on or off. and then of course some number of DC loads that can be switched on or off from a breaker panel. Some of those loads might be AC inverters. More complex systems would have more then one DC bus, but you are building a house not a ship.
The problem is that if you size an AC inverter for the worse case (lots of watts with a pure sine wave output) then most of the time it will be running in a very in-efficient way. It is best to run closer to the design point. If you do this they can be very efficient. You may find that only one load needs sine wave power and you can use much cheaper square wave inverters for most of your load.
For example I used a big and cheap AC inverter run off a 200 amp 12 DV branch to run things like a hand held hair drier and microwave and a small Sine wave inverter for things like an iPod charger. Many cheap power cubes do not like square wave power but hair dryers and light bulbs don't care.
In a whole house system you can save a few thousand dollars using the above method, money that can be put back into a larger battery bank or larger charging system.
One more thing. If you really are going to power an entire house from 12VDC seriously concider a second lighting system usiong 12V lights. The best ones now are LEDs. The battery power will go farther and the money saved on a large power inverter will pay for the LEDS
There are many people who live full time on 12V and almost none of them do it by converting the 12VDC to 120VAC and feeding that into the main AC pannel. "Grid tie" solar power system do it that way but by definition "grid tie" system are not off grid and can not serve the "UPS" function.
It is possible to build a combination grid tie inverter/UPS. That is, it will work as a grid tie inverter and a UPS at the same time. I have a friend who has built a grid interactive inverter. It is a UPS that can use alternative energy to partially offload the grid of the load, but it cannot supply power to the mains. Which means that if the alternative energy source (a hybrid bicycle in this case) cannot supply enough power to run the load by itself, it will use grid power to supply the remainder without resorting to batteries. The batteries are only used if the grid power is unavailable. (His final implementation just forces the 12v-180v DC/DC converter to start operating to hold the battery voltage to about 14.4v if an external source starts charging it beyond that voltage. The mains powered charger only charges to 13.8v.)
By replacing the input rectifier with a synchronized rectifier/inverter, it should be possible to make it into a combination grid tie inverter/UPS.
DC power distribution is also common in data centers, but not with 12v. The most common voltages are 48v and 370v. Most small networking equipment runs from 48v and the servers run from 370v without any modifications. 12v DC power distribution is occasionally used for small networks, though.
By replacing the input rectifier with a synchronized rectifier/inverter, it should be possible to make it into a combination grid tie inverter/UPS.
DC power distribution is also common in data centers, but not with 12v. The most common voltages are 48v and 370v. Most small networking equipment runs from 48v and the servers run from 370v without any modifications. 12v DC power distribution is occasionally used for small networks, though.
You don't need an inverter or DC/DC converter for that. Simply connect the iPod to the 12v supply with some simple protection circuits. The standby loss of an inverter and charger will probably be a lot more power than what the iPod actually uses. (Mine uses less than 10mA from a 12v supply when playing music. A small inverter easily uses a few hundred mA of standby load.)
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