Characteristics

1

Magnetization Curves

  The magnetic material is composed of the ferromagnetic or ferromagnetic matter. Under the action of external magnetic field H, there must be corresponding magnetization intensity M or magnetic induction intensity B, and their variation curves with the magnetic field intensity H is called magnetization curve (M ~ H or B ~ H curve).

  The magnetization curve is nonlinear in general and has 2 characteristics: magnetic saturation phenomenon and magnetic hysteresis. When the magnetic field intensity H is large enough, the magnetization intensity M reaches a certain saturation value Ms, and when H continues to increase, Ms remained unchanged. When the M value of materials reaches saturation and the external magnetic field H is reduced to zero, the M does not become zero, but changes along the MsMr curve. The working state of the material is equivalent to a point on the M - H curve or B - H curve, which is often referred to as the working point. 

2

Magnetic parameters of
soft Magnetic Assembly

  Saturation magnetic induction intensity Bs: its size depends on the composition of the material, and its corresponding physical state is the neat arrangement of the magnetic vectors within the material.

  The remanence Br: it is the characteristic parameter of hysteresis loop and, which the value of B when H backs to 0.
  Squareness Ratio: Br / Bs
  Coercivity Hc: it is the amount of magnetization that indicates the difficulty level of material magnetization, depending on the compositions and defects of the material (impurities, stress, etc.).
  Magnetic Permeability μ: it is the ratio of B to H at any point on the hysteresis loop, which is closely related to the working state of the device.
  Initial permeability μi, maximum permeability μm, differential permeability μd, amplitude permeability μa, effective permeability μe, and pulse permeability μp.
  Curie Temperature Tc: the magnetization intensity of ferromagnetic materials decreases with the increase of temperature. When reached a certain temperature, the spontaneous magnetization disappears and becomes paramagnetic, and the critical temperature is the Curie temperature. And it determines the upper limit temperature of the magnetic device
  Loss P: hysteresis loss Ph and eddy current loss Pe P = Ph + Pe = af + bf2+ c Pe∝ f2 t2 / , ρ declines, and the method to reduce the hysteresis loss Ph is to reduce the coercive force Hc. The method to reduce the eddy current loss Pe is to thin the thickness of magnetic materials T and improve the resistivity ρ of materials. The relationship between the loss of the magnetic core and the temperature rise of the magnetic core in free static air is: the total power dissipation (mw) / superficial area (cm2).
3

The conversion between
the magnetic
parameters of soft
Magnetic Assembly
and the electrical
parameters of the
devices

  The conversion between the magnetic parameters of soft magnetic materials and the electrical parameters of the devices

  When designing the soft magnetic devices, the voltage and current characteristics of the device must be determined according to the requirements of the circuit. The voltage and current characteristics of the device are closely related to the shape of the magnetic core and the magnetization state. The designer must be familiar with the magnetization process of the material and master the conversion relationship between the magnetic parameters of materials and the electrical parameters of devices. The design of soft magnetic devices usually consists of three steps: correctly select the magnetic material; reasonably determine the shape and size of the magnetic core; according to the requirements of magnetic parameters, simulate the working condition of the magnetic core can acquire the corresponding electrical parameters.


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