2025-02-10 
828The frequency characteristics of inductors are mainly influenced by three factors
A、 The main impact of magnetic core material loss is that it causes the Q value to exhibit a negative slope after reaching its maximum value.
B、 Dielectric loss is also a factor that affects, especially in the high frequency range.
C、 The third influencing factor is the self resonant effect of distributed capacitance and inductance.
The self resonant frequency has a negative impact on the performance of inductors. The self resonant frequency is determined by the distributed capacitance and self inductance, and the distributed capacitance is determined by the winding method. Minimizing distributed capacitance is a very important consideration in wire winding design. For the winding of a ring-shaped magnetic powder core, its effective capacitance is parallel to the inductance, and this distributed capacitance is the sum of the capacitance between lines, layers, and between the winding itself and the magnetic powder core.
Good winding design techniques aim to minimize the voltage between turns and minimize distributed capacitance, such as dividing the winding into several groups or using winding bars to effectively reduce electrical capacity. In winding and internal segmented connection techniques, it is advisable to avoid placing the input and output terminals too close to each other, as there is potential energy between the two parts, which distributes the effective capacitance value of the sensitive word. At the same time, humidity indicators and insulation constants of potting and packaging materials will also increase the distributed capacitance value.
For precision wound magnetic cores, high time stability and good temperature repeatability are required. So, during its temperature cycle, the winding stress must be released. When the magnetic particle core is wound, the coil must be subjected to as many temperature cycles as possible from the room to 125 ℃. This temperature cycle is not only to release stress, but also to remove humidity. When the temperature cycle is completed, the inductance of the inductor must be post adjusted.
After winding, the magnetic core must be kept dry and soaked, sealed or sealed as soon as possible. The sealing compound material should be carefully selected to avoid some materials shrinking over time and temperature, which may affect stability. Adding some padding material outside the magnetic core after winding can improve this effect.
For design engineers, understanding the conditions under which thermal aging causes an increase in magnetic core loss is crucial. At high frequencies, eddy current loss is the main loss, while at low frequencies, magnetic leakage loss is the main loss. And the proportion of various forms of loss in the total loss will also be affected by the magnetic flux density. The eddy current part of the magnetic core loss is affected by high temperature thermal aging.
By using an open air gap in a ferrite core, the effective magnetic permeability of the core can be reduced, thereby reducing the working magnetic flux density. However, this air gap can cause serious localized air gap losses, especially significant when the frequency is higher than 100KHz. In many cases, air gap losses exceed core losses. Due to the uniform distribution of air gaps in magnetic powder cores, such localized air gap losses are basically non-existent.
Chenzhou Gaohong Electronic Technology Co., Ltd
Dongguan Gaolu Electronics Co., Ltd
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