Comparison of the characteristics of commonly used soft magnetic cores

1. Comparison of the characteristics of magnetic powder core and ferrite:

MPP magnetic core: using ampere turns of 200, 50Hz~1kHz, e: 125~500; 1 ~ 10kHz； e ：125 ~ 200； 100kHz：e： 10 ~ 125

HF magnetic core: with an ampere turn count of 500, it can be used on larger power sources and is not easily saturated under larger magnetic fields, ensuring the minimum DC drift of the inductance, e: 20~125

Iron powder core: With an ampere turn count of 800, it can not be saturated under high magnetization fields and ensure the best AC/DC superposition stability of inductance value. Stable frequency characteristics within 200kHz; But with high frequency loss, it is suitable for use below 10kHz.

FeSiAlF magnetic core: used instead of iron powder core, with a frequency of over 8kHz. The DC bias capability is between MPP and HF.

Ferrite: Low saturation magnetic density (5000Gs), minimum DC bias capability

3. Comparison of characteristics of silicon steel, permalloy and amorphous alloy:

Silicon steel and FeSiAl materials have high saturation magnetic induction values Bs, but their effective magnetic permeability values are low, especially in the high-frequency range;

Permalloy has high initial permeability, low coercivity and loss, and its magnetic properties are stable, but Bs is not high enough. When the frequency is greater than 20kHz, the loss and effective permeability are not ideal, the price is expensive, and processing and heat treatment are complex;

Cobalt based amorphous alloys have high magnetic permeability, low Hc, low losses over a wide frequency range, a saturation magnetostriction coefficient close to zero, and are not sensitive to stress. However, their Bs value is low and they are expensive;

Iron based amorphous alloys have high Bs values and low prices, but their effective magnetic permeability values are relatively low.

The magnetic permeability and Hc value of nanocrystalline alloy are close to those of crystalline high permalloy and cobalt based amorphous, and the saturation magnetic induction Bs is equivalent to that of medium nickel permalloy. With simple heat treatment process, nanocrystalline alloy is an ideal low-cost high-performance soft magnetic material; Although the Bs value of nanocrystalline alloys is lower than that of iron based amorphous and silicon steel, their high-frequency losses under high magnetic induction are much lower, and they have better corrosion resistance and magnetic stability. Compared with ferrite, nanocrystalline alloys have a working magnetic inductance of 2 to 3 times higher with lower losses at frequencies below 50kHz, and the magnetic core volume can be more than twice smaller.