Design of Iron Powder Core Filter Inductor 2

In the past, electronic devices such as those using electronic tubes often had high voltage and low current rectified outputs. However, today's electronic devices that use transistors and integrated circuits mostly have low voltage and high current. Due to the direct proportionality between DC magnetization force and current magnitude, it is even more important to pay attention to the impact of DC magnetization on inductance. This requires that the filtering inductor must be adapted to high current conditions. Therefore, what kind of material should be chosen for the magnetic core. How to design a filter coil well, reduce the influence of DC magnetization, and prevent magnetic core saturation, has become a problem worthy of attention.diode

Regarding the characteristics of constant magnetic permeability or constant inductance

The rectifier filter inductor operates under high DC current conditions, and the smaller the change in inductance value caused by changes in operating current, the better. That is to say, it is required that the DC magnetization of the magnetic core has a relatively small impact, that is, it has some kind of constant magnetic permeability. Due to the influence of DC magnetization, the inductance tends to saturate, and the inductance decreases as the operating current increases. According to everyone's consensus, the so-called constant magnetic permeability characteristic, also known as constant inductance characteristic, refers to the inductance of an inductor within a certain range of DC magnetization force, which is not less than half of the initial inductance. By mastering this characteristic, we can achieve different percentage requirements by selecting different magnetic cores and specifications.diode