Characterization of variable inductors using finite element analysis

A Review of Tunable Inductors for Power Electronics: Techniques and Applications

“…There are three main approaches utilized to control the relative permeability of magnetic cores: 1) current-controlled approach, and it is the most popular one that utilizes an external DC bias current to adjust the relative permeability of the magnetic core; 2) liquid-controlled approach, and it is the less popular approach that employs MEMS technology in conjunction with liquid fluids to alter the relative permeability of the medium, which represents the magnetic core in that case; 3) voltage-controlled approach, still-evolving technology that employs an external DC bias voltage to adjust the relative permeability of the magnetic core. The first technique is DC current bias, also known as actively current-controlled variable inductors, and is the most frequently utilized in power electronic converters, as discussed in [16], [20], [21], [22], [70], [71] , [72], [73], [74], [75], [76], [77] and [78]. While, the second and third approaches are less popular in power electronic applications.…”

Performance enhancement of powertrain DC–DC converter using variable inductor

“…To quantify these concepts, it is important to include the impact of ripple current in influencing the copper and core losses. The detailed analytical expressions that relate this explanation are presented in [14]. The levels of current ripple also influence the switching losses.…”

“…In this case, Q v ðsÞ will be the product of ( 14) and the inverse of (9) excluding the NMPZ. When the NMPZ is eliminated, the relative degree of ( 9) is 1, hence F Q ðsÞ can be selected in the same way as (14) with values of α different from (14), and Q v ðsÞ will be as shown in (16):…”

“…The inductance variation of the VI is derived from the linkage flux information using the procedures presented in detail in [14]. The characteristics curves obtained in this section are used in the model of the power inductor to explore the features of the VI for improving the performance of powertrain DC–DC converters.…”

“…The detailed modelling and characterisation of a small-scale VI for its potential importance in enhancing current-handling capability is explored in [8,14]. The detailed characterisation reveals the need for a suitable strategy that determines the suitable levels of auxiliary winding current to exploit the prominent merits of the current-controlled device.…”