Industrial switching power supply

[xieliwei]

Hi all,

I'm designing a motor controller board for consumer and industrial usage and have some doubts about the power supply aspect. I'm trying to see if I can integrate the power supply into the board's design to simplify assembly and stock-keeping. The problem is, the product will be running off common household mains (110-240VAC) as well as industrial voltages up to 600VAC. Handling household mains is not a problem as I can use off the shelf components or modules, but once I include industrial voltage ranges in my search, nothing suitable comes up.

My board (sans motor) will consume less than 10W of power at 12V. Is there a sensible way to include a cheap on-board switching supply that accepts 110-600VAC? Industrial voltages are three phase, but I figured I can run off two out of the three delta lines since an unbalance of 10W shouldn't have much effect on the system. Is this a good idea?

One idea I came across is to use a multi-tap transformer at the rectification stage of the switching supply to step the voltage down to something the switcher can handle. Is this idea feasible?

 

[ronsimpson]

The wider the input range the harder it is to design a switcher. 110-600vac That means low voltage 110 which is 100 or maybe 90V and also high 600 which is 660 or more.

600vac when rectified and filtered becomes 840 volts DC. You will need 2kv diodes and 1kv capacitors. Your silicon needs to exceed 1kv and there is not much there. I made a 440 supply recently and the price was too high. We found that most industrial locations have a small transformer that knocks the line down to 110/220 for driving instruments.

 

[xieliwei]

Thank you for the insight! I also realised PCB design will be a pain with the need to have 1kV clearance. I guess the best way to deal with this is like you said, to have a small transformer.

This leads me to two more questions:
1. Is there a way to auto-detect line voltage and switch to the required winding automatically? Did some searching but couldn't come up with anything like that.

2. Transformer selection. It seems like transformers for 600V, regardless of how low its load ratings are, are quite big, somewhere the size of a tennis ball. Is there a way around that?