I'm doing an industrial project, i need to step down the high voltage of 2kV to 5V, is it possible to step down to around 5V without transformer, is there any other alternatives? please suggest me :)
closed as unclear what you're asking by Olin Lathrop, laptop2d, DoxyLover, Bimpelrekkie, jonk Nov 1 '17 at 20:50
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If all you need is to get a sample the voltage with an ADC (I saw your comment in Peter Green answer), just make a voltage divider.
Hook some 1/2W high ohm resistors in series between 2kV and ground, trying to make each one see at most 500V, and a last resistor proportional to the 5V you want. Something like this:
Vcc --- 20MΩ --- 20MΩ --- 20MΩ --- 20MΩ --x-- 200kΩ --x-- GND
The first four resistors are of high value because too low resistors will load your 2kV source, drawing a big current which may cause voltage drop and overheating on the resistors. And you want to use several of them (four), instead of just a big one, because each resistor has a voltage limit. Above that, voltage may arc from a lead to another, creating unwanted fireworks.
This network will draw a low current: about 25µA. The last resistor is where you will hook your ADC (note the x), and it´s calculated this way: 5 * 80000000 / 2000 = 200kΩ. This resistor will have about 5V of the total 2kV. The remaining 1995V will be distributed between the 20MΩ resistors. If you want to be on the safe side, decrease the 200kΩ a little, to have less voltage on it, preventing accidents by overvoltages on your ADC.
You need to answer a few questions.
- Do you need isolation?
- How much power do you need?
- What efficiency and/or power factor do you need?
If you need isolation that pretty much pushes you into using a transformer somewhere in the design though it may make more sense for it to be a high-frequency transformer in some kind of switched-mode converter.
If you don't need isolation then other approaches become possible. For example a buck converter or for small ammounts of power a capacitive dropper.
2kV components are bulky. That's because of the insulation needed, but more important, because no one bothers with 2kV when he doesn't need 2MW. Even 200kW stuff would be done at 690V, to allow 1kV insulation and a wider and cheaper selection of components.
So … if you want something small at 2kV, you have to build most of the components yourself. Sometimes a series connection of low-voltage components will help (e.g. 1N4007 goes up to 1kV) but most times, you are out of luck.
So winding a 2kV->690V transformer yourself will solve a lot of headaches. You will still hardly come down to the size of a cell phone charger. These are incredibly tiny.