What's the advantage of paralleling the DC Bus Voltages of some drives ?

[phatcreators]

What's the advantage of paralleling the DC Bus Voltages of some drives ?

 

[FvM]

E.g. energy recuperation. A motor inverter can feed energy back to the DC bus, but not the mains supply. The energy can be consumed by another motor in a shared DC bus or must be absorbed by a breaking resistor circuit.

 

[pico]

It depends on the need of the application. Some application needs more reliable operation, so it make a parallel supply for redundancy.

 

[phatcreators]

don't you think its because of the fact that if any one's power supply (DC Bus voltages are failed) then the other's power supply will make up the operation without any break ?

 

[FvM]

Depends on which failure mechanism you assume more likely, supply failure or failure of DC bus and inverter stage short. In the latter case, the parallel circuit will reduce reliability rather than improving it.

I don't think that higher reliablility is a premier purpose of the parallel circuit.

 

[pico]

Depends on which failure mechanism you assume more likely, supply failure or failure of DC bus and inverter stage short. In the latter case, the parallel circuit will reduce reliability rather than improving it.

I don't think that higher reliablility is a premier purpose of the parallel circuit.

Parallel always make higher reliability. It does not just only connect wires in parallel it will have protection system (At least has a diode in serys), so if any one fail wil not effect the whole.

 

[phatcreators]

so why don't we always use this protective technique ?

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Is it the protective technique for DC Bus Voltages or for what ?

in my view if DC Bus voltages are failed of any drive then it won't be generating the output (U,V & W) ???? what do you think & say ?

 

[FvM]

Parallel always make higher reliability. It does not just only connect wires in parallel it will have protection system (At least has a diode in serys), so if any one fail wil not effect the whole.

I see, that you didn't actually analyze (or at least not understand) the operation of the circuit under discussion. There's no way to protect it against bus shorts by series diodes. So a short of one bus capacitor or output stage will stop all connected drives.

That isn't a particular problem, because machine operation depends on availability of all drives. For the same reason, you would ususally generate an emergency stop if any of the supplying circuit breakers trips, presumed it's monitored by the machine PLC.

 

[phatcreators]

i was referring to pico's answers because he used to keep saying it protective technique

 

[FvM]

i was referring to pico's answers

I know, I was referring to it, too.

 

[pico]

i was referring to pico's answers because he used to keep saying it protective technique

If each supply has a diode in sery. when any of the supply fail it will not effect other supply to the load.

 

[phatcreators]

so FvM kindly argue with Pico & argue with his answers ..... why its not protective technique ?

 

[FvM]

For the intended purpose of DC-bus parallel operation, refer to chapter 10 in the Lenze 9300 series system manual.

http://src.lenze.com/lenze-bibliothek/en/_start.htm

 

[pico]

Oh, I see. It's my miss understanding as the case of another topic.

https://www.edaboard.com/threads/263422/