We Mean Inductor Or Inductance

Note that in the previous section, we said nothing explicitly about what the inductance was — we just talked about the size of the inductor. We know that in theory, we can put almost any number of turns on a given core, and get almost any inductance. So inductance and size of inductor are not necessarily related. However, we will now see that in power conversion they often do turn out to be so, though rather indirectly. 

Since we are assuming our application conditions are fixed, the load current and input/output voltages are also fixed. Therefore, Idc is fixed too. The only way we can cause r to decrease under these circumstances is to make AI smaller. However, AI is 

However, we must not forget that if, for example, we increase the load current (i.e. a change in application conditions), we will clearly need to move to a larger inductor (with greater energy-handling capability). But simultaneously, we will need to decrease the inductance. That s because Idc will increase, and so to keep to the optimum value of r, we will need to increase AI in the same proportion as the increase in Idc- And to do this, we have to decrease, rather than increase, L. 

Therefore the general statement that a large inductance is equivalent to a large inductor only applies to a given application. 

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