A Presentation of Magnetic Components

Magnetic components have been utilized in various power electronic devices for decades. It is used for electric power regulation, transmission, and cooling. To enhance performance, designers are continuously looking for novel materials, topologies, and methods.

In history, magnetic design was regarded more as art than science. Because the design was primarily based on experimental and error approaches, empirical formulas, and rules. Moreover, the design process has been standardized in many efforts to improve its reliability and repeatability.

Read about the design of the magnetic component known as the inductor and the main concepts and design principles in particular.

The Inductor History

The inductor was designed utilizing test procedures and error approaches such as Hanna curves in 1927. More dependable design techniques were subsequently established, such as the area-product method and core geometrical constant methods.

An equivalent magnetic circuit is modeled, and the relationship between different components is investigated to assess these approaches.

Electrical, mechanical, and thermal considerations affect the design of inducers. The design of an inductor generally includes the following steps:

• Selection of core material
• Selection of the core form
• Choice of core size
• Selection of winding wire

For power converter conversion systems with switched modes, inductors usually work in the linear area. As the dynamics of the closing loop are regulated by the capacity and inductivity values, the value of inductance is meant to be modest. In addition, the circuit inductance value controls the operating mode. This refers to the design of a considerable inductivity value to prevent discontinuous driving operation.

Likewise, the inductance with higher loads should be minimal and vice versa to provide maximum dynamic performance. These are all critical design criteria that cannot be compromised. Non-linear inducers are used rather than linear inducers. It shows a non-linear characteristic example of the inductor.

Components and concepts of the inductor key

Magnetic wire refers mainly to an enamel-coated wire of copper covered with isolation material layers. A range of magnetic wire forms are used for windings, including square or circular cross-sections, rectangle foil, or even Litz wire.

Isolation is used to prevent short circuits or failures on the bare copper wire surface. A magnetic core is used to limit and steer magnetic fields, and the shape and magnetic material are selected based on the needs of the intended use.

Critical material selection is determined by:

• Important harmonics of the operational frequency
• Responsible permeability
• The magnetic density peak value
• The maximum magnetic flux density amplitude is determined based on the growth in temperature limitations
• Selection of the iron-powdered and ferrite materials based on design restrictions

The choice of the core is regulated by:

• core size
• core shape
• core volume
• winding window considerations
• air gap

The choice of a winding driver must be determined by:

• conductor shape
• conductor size
• insulation
• number of layers
• number of turns per layer