INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Grid tie Inverters Design Query

Grid tie Inverters Design Query

(OP)
Dear All,

I am currently working on a design of Grid Tie Inverter where the source of power is from a Lead acid battery. The inverter converts the DC to AC and will feed it the Grid.

In low power range of less than 200W boost converter are used to step up the DC and then convert this voltage to AC.
But my design has a minimum power of 1000W (1KW) and higher (3KW, 5KW etc) designs are in pipeline. The Mains voltage is 230V

My doubt here is that can this be achieved with boost convertor or its better to use a transformer where the low voltage AC can be stepped up to high voltage AC. I have this query cos i have seen some 5KW Grid Tie inverter which are sleek and lightweight, so i doubt if the design is transformer based.

Thanks
Regards
Gokkul

RE: Grid tie Inverters Design Query

Why not conduct some 'market research'? ...Where you purchase some existing/competitors' products and open them up for examination and analysis. Along the way, one might gather up patent pending/number notices leading to more technical information (from the patents, available online) and perhaps learn about requirements for licensing or patents to work around.

If the product procurement Ts&Cs includes a legal notice that attempts to ban 'reverse engineering', then double check with your lawyer. Perhaps buying 2nd hand would leave such Ts&Cs behind.

You could also search the USPTO.gov website for applicable keywords.

RE: Grid tie Inverters Design Query

(OP)
Thanks for the guidance, but this option is my plan B. initially i wanted to get some info on the design from the forum if it did not work then plan B is reverse engineering :).

Thanks
Regards
Gokkul

RE: Grid tie Inverters Design Query

One sometimes-useful Project Management technique is the simultaneous execution of parallel options. It can push right decisiom points allowing immediate progress, eliminate risks and compress schedule; often for miniscule investments of effort and money.

In other words, if a project team is considering Plans A, B, C, etc., then begin execution of the long leadtime, low investment activities of all the even-slightly-likely Plans at once.


Hopefully someone with directly applicable grid-tie inverter experience will join in eventually. Good luck.

RE: Grid tie Inverters Design Query

This is a thoroughly researched area and you'll find plenty of material on the pros and cons of the various approaches. Last I heard, the transformerless topologies were winning out in terms of efficiency, weight and volume, provided that the lack of isolation didn't pose a problem. Given your power source is a battery, isolation is probably not a big deal.

At your power range a boost stage is not unreasonable. It'd be worth trying to specify your battery voltage as high as possible to minimise losses in the boost stage. 5kW from 300V batteries is probably fine. As your battery voltage falls, the advantages of a transformerless design start to diminish.

Here's a good start for a comparison of transformer/transformerless topologies:

http://ieeexplore.ieee.org/iel5/41/5662271/0506731...

RE: Grid tie Inverters Design Query

(OP)

Quote (LiteYear)

At your power range a boost stage is not unreasonable. It'd be worth trying to specify your battery voltage as high as possible to minimise losses in the boost stage. 5kW from 300V batteries is probably fine. As your battery voltage falls, the advantages of a transformerless design start to diminish.

You read my mind :).

My doubt exactly that if the battery voltage is too low then a inductor based system will be complex. I will look into the problem and try to design the system so that the battery voltage remains high enough for minimum boost of voltage.

Thanks for the feedback.

Thanks
Regards
Gokkul

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close