Efficiency
Active losses of a converter are
1) The thyristor losses ∆ РT.
2) The transformer losses
∆РTr = ∆РSt+ ∆РCop,
where ∆РSt - steel losses;
∆РCop - Cop-losses in windings.
3) The reactors losses ∆РR (anodic, smoothing and current-balancing).
4) Losses in the auxiliary equipment (a control and regulation system, cooling system) ∆PAux.
∆РSt and ∆РAux are constant and are not load-depending.
For middle-and high-voltage sets
where m - number of thyristors in the circuit,
∆UT - a voltage drop on the thyristor.
More precisely if to take into account current-voltage diagrams of the thyristor
where kf - the form factor.
Then, for low-voltage rectifiers
Primary windings of the transformer losses
where n1 - number of primary windings,
R1 - resistance of a primary winding.
Secondary windings losses the transformer
where n2 - number of secondary windings;
R2 - resistance of secondary windings.
Reactor losses
where ∆РSmR – the smoothing reactor losses,
∆РCBR - the current-balancing reactor losses,
∆РAR - the anodic reactor losses.
The core of reactors losses, as a rule, do not take into account.
Thus, at Ld≈∞
At Ld <∞ it is necessary to add a addendum into a denominator
For converters of low power
where η Th – thyristor block efficiency,
η Tr - transformer efficiency,
η f – filter efficiency.
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