Paralleling Power Supply Units Made Easy ???

Salvo wrote:
Phil, if you understand feedback theory then you know there's absolutely nothing to worry about. Both supplies have adequate phase & gain margin.

You will never, ever see instability. Guaranteed!

As for saying "When paralleling 2 supplies that are not designed to be paralleled together, you are effectively injecting a dynamic disturbance into each supply's independent feedback control loop.", that's BS. Adequate phase and gain margin will reject any dynamic disturbance. Plain and simple. This is as basic as it gets in feedback theory.

Sal

Quick review:

Gain and phase margins are determined using the open loop, loop gain, and are typically determined at one frequency only.

To determine if noise or a disturbance can create an issue, the noise would need to be modeled, or physically injected, at the output node and a new open loop gain/phase response would need to be determined.

The designed loop may very well handle any of these disturbances, or a whole new dynamic at a new frequency may be created that was not anticipated and instability could occur.

You cannot say for sure that there is absolutely no issues when paralleling supplies without much more information about said supplies - my caution comments...

Are you sure these cheap Chinese supplies are designed to such wide gain/phase margins?

Why do power supplies that are designed to be operated in parallel mode have a single loop, or master/slave, control loop design?

I have no idea if any supply will play nice when paralleled and would never make a claim that it would without some serious testing just to be sure...

But, hey you must be correct since you can guarantee there are no issues...

Ken