[SOLVED] High Frequency Transformer based inverter

[francis29]

As far as i know all commercially available sine wave inverters in the market right now are bulky low frequency
transformer based. Is there any manufacturer that makes high frequency transformer based inverter??
Low frequency tx based--- Battery>>dc bus12V>>Hbridge(sine pwm)>>low freq transformer>>230v pure sine wave.
High frequency tx based--- Battery>>pushpull(high freq tx)>>dc bus 400V>>Hbridge(sine pwm)>>filter>>230v pure sine wave.

 

[brushhead]

The output transformer makes it impossible for DC current to appear at the output if the modulation goes haywire for a start? Sine filtering will also add mass in the form of the filter inductors.

 

[FvM]

As far as i know all commercially available sine wave inverters in the market right now are bulky low frequency transformer based.

No, no. There are many converters with high frequency DC/DC converter and pwm output stage on the market.

 

[francis29]

can you please suggest some brands below 3KVA??

 

[FvM]

Most "true sine wave inverters" you found at Ebay and elsewhere are clearly lacking a low frequency transformer according to size and weight. In case of doubt all types with "brick" form factor.

https://www.amazon.com/Sunforce-11240-Inverter-Remote-Control/dp/B000WGNNUQ
https://www.theinverterstore.com/12-volt-pure-sine-inverters.html

I can't suggest a particular type because I don't use it.

 

[francis29]

I couldn't find any in indian market. How to find out whether it is high freq tx based or low freq tx based??

 

[nikhilmahasvar]

There are couple of manufacturers in India who makes HF transformer based Sine wave UPS's but so far none of them could get good market share due to poor reliability and the complication in servicing.

The only advantage with HF transformer based design is The efficiency and size. But it may not be suitable for the Indian power conditions unless it is designed so very well.

Damages due to lightning is also very high comparatively.

 

[francis29]

Efficiency,size,weight wise how much they differ??
Is it not allowed to say the name of who those manufactures are??
If it is not allowed its okey.

 

[Warpspeed]

One basic problem with high frequency high voltage H bridge inverters is they are very fragile and easily prone to blowing up.

The heavy bulky transformer inverters are far more robust, and will handle short term overloads much more readily.

The high frequency type might suit a mobile application where it is only powering one specific load, and is unlikely to see any overload abuse.

If this is for general home use, I strongly recommend you stick with the big old heavy clunky transformer inverter. It will run refrigerators and flourescent lights with ease and just occasionally harmlessly blow the occasional fuse.

 

[smijesh]

Is it not allowed to say the name of who those manufactures are??

Su Kam Having high frequency inverter but it is not popular in India due to reliability. Company is situated in Gurgon India
Is it not allowed to say the name of who those manufactures are??
**broken link removed**

Efficiency,size,weight wise how much they differ??
You cant expect size reduction of 1/3 when going with high frequency transformer based inverter. In this method the transformer size may reduce to 1/3 and efficiency(Transformer) may increase(70% to 95%) compared to low frequency transformer. but filtering stage will introduce in high frequency based inverter. Battery,Inverter circuit, control and protection circuit will decide the size of the inverter

 

[FvM]

If this is for general home use, I strongly recommend you stick with the big old heavy clunky transformer inverter. It will run refrigerators and flourescent lights with ease and just occasionally harmlessly blow the occasional fuse.

50 Hz transformer inverters can be made by backyard small business without much electronic skills and still have good life expectancy.

But you should also consider that high voltage inverters are made in x 100 million quantity for variable frequency drives and quite a lot for grid tied solar power. They can be designed reliably and fully overload protected these days.

 

[francis29]

Yeah that's true. But most countries asks for isolation i think. So some kind of transformer in the circuit is necessary right??

 

[Warpspeed]

5
But you should also consider that high voltage inverters are made in x 100 million quantity for variable frequency drives and quite a lot for grid tied solar power. They can be designed reliably and fully overload protected these days.

This is very true, but the inverter designer knows that with a motor drive or a grid tie inverter pretty much what the operating conditions are going to be. So many Hp motor, or so many Kw grid tie. Its possible to design suitable protection that will work well within reasonable limits that can be thoroughly tested.

The designer of a "general purpose" inverter for home use has absolutely no way of controlling what some really dumb users will plug into it.

Some guy will buy a 500 watt inverter, will hook it up to the battery in his car and plug in a 150 amp stick welder.
When the inverter inevitably goes *BANG* its because the guy that designed it was an idiot, and the inverter was crap, and he wants it fixed under warranty, or his money back.

A great many people believe owning an inverter is exactly like being hooked up to the grid.
You can just connect absolutely anything at all to it and it will work just fine.

 

[francis29]

cost wise which one is good??

 

[Warpspeed]

Cheapest will always be a poorly designed high frequency inverter.
Large transformers always use a lot of copper and steel which is expensive.

 

[nikhilmahasvar]

High frequency Inverter gives good efficiency with moderate cost. But if you want to get good efficiency in transformer based models it will be very costly.
How ever reliability will be definitely at a risk in Indian power conditions unless the HF model is designed very well but then the cost goes high.