What is a saturable inductor ?
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A saturable inductor is an inductor which is designed to saturate. This kind of inductor is particularly used in snubber circuits. In [1] a typical B-H curve is shown that forms the two properties of the saturable inductor as shown in Fig.1.
First property : There is a finite time required for the core to saturate. This is governed by the Faraday's law. This implies that the the core has high permeability and hence high inductance and therefore the rate of change of current is low.
Second property : Once in saturation the core permeability decreases towards Uo. This means that the rate of change of current will increase but the core stored energy does not increase significantly.
Reference:
[1] Finney, S.J., Tooth, D.J., Flethcer, J.E. and Williams, B.W., 1999. The application of saturable turn-on snubbers to IGBT bridge-leg circuits. Power Electronics, IEEE Transactions on, 14(6), pp.1101-1110.
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| Fig.1 : B-H curve for saturable core |
First property : There is a finite time required for the core to saturate. This is governed by the Faraday's law. This implies that the the core has high permeability and hence high inductance and therefore the rate of change of current is low.
Second property : Once in saturation the core permeability decreases towards Uo. This means that the rate of change of current will increase but the core stored energy does not increase significantly.
Reference:
[1] Finney, S.J., Tooth, D.J., Flethcer, J.E. and Williams, B.W., 1999. The application of saturable turn-on snubbers to IGBT bridge-leg circuits. Power Electronics, IEEE Transactions on, 14(6), pp.1101-1110.
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