What kind of magnetic ring material is fe si

1. Magnetization curve of magnetic materials

Magnetic materials are composed of ferromagnetic materials or ferromagnetic materials. Under the action of external magnetic field H, there must be corresponding magnetization M or magnetic induction B, and their change curve with magnetic field H is called magnetization curve (M-H or B-H curve). The magnetization curve is generally nonlinear and has two characteristics: magnetic saturation and magnetic hysteresis. That is, when the magnetic field strength H is large enough, the magnetization M reaches a certain saturation value Ms, and continues to increase H, Ms remains unchanged; And when the M value of the material reaches saturation and the external magnetic field H decreases to zero, M does not return to zero, but changes along the MsMr curve. The working state of a 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. Common magnetic properties parameters of soft magnetic materials

Saturated magnetic induction intensity Bs: Its magnitude depends on the composition of the material, and its corresponding physical state is the orderly arrangement of magnetization vectors inside the material.

Residual magnetic induction intensity Br: is a characteristic parameter on the hysteresis loop, the B value when H returns to 0.

Rectangle ratio: Br/Bs

Coercive force Hc: refers to the degree of difficulty in magnetization of a material, which depends on its composition and defects (impurities, stress, etc.).

Magnetic permeability: refers to the ratio of B to H corresponding to any point on the hysteresis loop, which is closely related to the operating state of the device.

Initial permeability i, maximum permeability m, differential permeability d, amplitude permeability a, effective permeability e, and pulse permeability p.

Curie temperature Tc: the magnetization of ferromagnetic materials decreases with the increase of temperature. When it reaches a certain temperature, the spontaneous magnetization disappears and changes into paramagnetism. The critical temperature is the Curie temperature. It determines the upper limit temperature for the operation of magnetic devices.

Loss P: Hysteresis loss Ph and eddy current loss Pe P=Ph+Pe=af+bf2+c Pe Å f2 t2/, reduced,

The method of hysteresis loss Ph is to reduce the coercive force Hc; The method to reduce eddy current loss Pe is to reduce the thickness t of magnetic materials and increase their electrical resistivity. The relationship between the loss of the magnetic core in free still air and the temperature rise of the magnetic core is:

Total power dissipation (mW)/surface area (cm2)

3. Conversion between the magnetic parameters of soft magnetic materials and the electrical parameters of devices

When designing soft magnetic devices, the first step is to determine the voltage current characteristics of the device based on the circuit requirements. The voltage current characteristics of the device are closely related to the geometric shape and magnetization state of the magnetic core. The designer must be familiar with the magnetization process of the material and grasp the conversion relationship between the magnetic parameters of the material and the electrical parameters of the device. Designing soft magnetic devices usually involves three steps: selecting magnetic materials correctly; Reasonably determine the geometric shape and size of the magnetic core; According to the magnetic parameter requirements, simulate the working state of the magnetic core to obtain the corresponding electrical parameters.