The choice of coil magnetic material will determine the high power wireless charging system. Since the surface temperature rise of the low-power wireless charging system is not obvious, the physical properties such as the magnetic permeability and the resistivity are not prominent regardless of the type of magnetic material selected. However, when designing a high-power wireless charging coil, The effect of the system temperature on the characteristics of the coil, and the frequency band to which each magnet is applied, as this will significantly affect the efficiency of the wireless charging coils .
In general, the wireless charging coil composition can be roughly divided into four parts, namely by the aluminum composition of the heat, ferrite magnetic components, protective film (PET) and wire (Coil); in the choice of wire, Taking into account the thickness of each material, impedance, winding accuracy; magnetic components should be selected to consider the permeability, magnetic saturation characteristics, resistivity and applicable frequency and other factors, which will affect the efficiency of wireless charging power transmission system which performed.
However, in fact, in the design of low-power wireless charging coils manufacturer the relative permeability and resistivity of manganese zinc with nickel-zinc is almost the same, unless the system for a long time under continuous operation, resulting in a significant increase in system temperature will be generated Some very small gap; therefore, low-power wireless charging coil design for the selection of the material is not if the choice of wire-like preoccupied.
But if more than 15 watts of wireless charging system, the magnetic surface temperature rise will be more obvious, which will make the magnetic material resistivity, permeability and other physical properties more prominent, so the choice of the material must be considered The effect of temperature on the physical properties of the magnetic material. In view of this, Wang Shiwei said that in the design of high-power wireless charging coil, it should be selected low magnetic permeability, but the higher resistivity of the magnetic material; as long as the use of impedance starting point is higher than 1MHz of the magnetic material, high power wireless charging system Resulting in high-frequency noise that can easily be eliminated, so that high-power wireless charging system efficiency and then upgrade.
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