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External characteristics

Figure 2.3

I - a rectifier conditions;

II - inverter condition;

ΔU_x has the as same sing as a no-load voltage.

As

then in case

δ=0 will be β=γ.

The range of a modification β is limited by an angle δ, allowable by the given type of a thyristor.

β_min = δ₀ + γ,

when δ₀ - classification parameter for the given type of a thyristor.

Usually δ₀ = 0.2 degree at f _c= 50 Hz.

Principle of operation for more complex inverter’s schemes is one and the same. Consequently, all circuits of the rectifying may be used for a current inverting. For this purpose it is necessary to change a sign opposite - EMF and a commutation delay angle to make more than 90 degrees.

All equations of dependences I_d = f(α, γ, X_а) and an external characteristics U_dα =f(I_d) of rectifiers are fair to dependent inverters if to replace on α to π-β.

Then for the considered scheme

The same one is for other circuits of rectifying and inverting.

The dependentinverters are widely applied for an electrical haulage, for the electric drive to braking DC for current recuperation to a supply network, for the electric drive of an alternating current by the rectifier cascade scheme, for systems of DC power lines etc.

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