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  • Author Author: station240
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Why I don't own a benchtop PSU, for my solar projects

station240

As my areas of interest are power electronics, SMPS, solar power and related areas of Microcontrollers and opamps, any form of PSU I use for testing has to be suitable.

 

But most of the electronics can be powered from simple fixed voltage supplies.

3.3V MCU.

5V logic/modules.

12V relays.

+/-15V opamps and current sensors.

So I have a box of mains powered PSU modules I can use as is.

 

What does need a variable supply to test is the main DC bus (~400V) of SMPS and solar related inverters. Find whatvoltage range the circuits function, I've already found some work at far lower voltages than their label says.

Then you need to simulate a solar panel/array, but these days of 60 cell (40V max), 72 cell (50V max), 96 cell (64V max), even a single panel would require higher voltages than the average bench PSU.

Plus real solar panels have varying V/A curves, which you need to simulate to test MPPT functions, that means a programmable PSU or one with inbuilt solar simulator.

 

So you bog standard 0-30V benchtop PSU is almost entirely useless to me.

 

What I would like turns out to be a rare, and hard to obtain 'high voltage' supply, which are not only not mass produced, but often only in higher power ratings.

Some day I'll just build me own 0-400V DC supply, after a lot of careful planning.

  • in reply to rsc

    I used High voltage in quote marks for a reason, I only need 0-400V, or maybe as far as 600V.

    The technical term for <1KV supplies is Low Voltage, a term I refuse to use as it implies low risk which isn't the case.

     

    Microwave HV components are lethal, not something I have to worry about, as I haven't gotten a Microwave with a working HV section.

    Actually I do have a variac, but how can you software control a big heavy rotating contact ?

  • With a variac and a transformer from a microwave oven, you can get 0-3000VAC.  Add a couple of microwave diodes and a HV cap, and you have your HV DC power supply.

    Scott

  • Back in my tech school days we always had a 0-400 v DC power supply around to power the tube circuits we built. They were about the size of a toaster with a substantial transformer and basic rectification and filtering.

     

    That said, you can always test your basic components at lower voltages and then just connect them together for scale. Solar cell devices have a fairly predictable output and the products are very consistent.

     

    DAB