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What Are Soft Magnetic Materials and What They Are Used For?

What Are Soft Magnetic Materials and What They Are Used For?

Issue Time:2021-01-10
Soft magnetic materials and their related devices (inductors, transformers, and electrical machines) are often overlooked; however, they play a key role in the conversion of energy throughout our world. Conversion of electrical power includes the bidirectional flow of energy between sources, storage, and the electrical grid and is accomplished via the use of power electronics. Electrical machines (motors and generators) transform mechanical energy into electrical energy and vice versa.

Soft magnetic materials are key to the efficient operation of the next generation of power electronics and electrical machines (motors and generators). Many new materials have been introduced since Michael Faraday’s discovery of magnetic induction, when iron was the only option. 
Soft Magnets can be classified by several standards, Below, we categorize by the material features and its application.

Classification by material characteristics
Low frequency (50Hz ~ 60Hz mains): silicon steel, Fe-Ni alloy, etc
Medium frequency (400Hz ~ 20KHz): amorphous, nanocrystalline, ultra-thin silicon steel, etc.a
High frequency (100KHz ~): soft magnetic ferrite, magnetic powder core (Fe-Si, Sendust, HF, Iron Powder, etc.)

Classification by application field
Inductor (reactor)
Magnetic shielding

Amorphous core and device
Active Power Filter and Reactive Control

Where are all soft magnetic devices used?

Electromagnetism is not divided into homes, and soft magnetic devices are used in most places where electricity is used.
The most commonly used place: power supply system, for example, is as follows

1. USB interface voltage 5V, mains 220V
2. Apple mobile phone charger, 220V: 5V uses 1 transformer +1 inductor
3. Android phones are similar in structure after disassembly, using 1 transformer +1 inductor,
4. Adapter

The most commonly used place: power supply system, for example, is as follows

1. Medium frequency induction heating power supply
2. Large magnetic devices in intermediate frequency power supply include:
3. Main Transformer
4. Reactor

The so-called power supply system does not refer to a simple power supply.

Where frequency, voltage and current conversion is required, it may be covered. For example, photovoltaic power generation voltage is generally 18/27/30/36/48 V DC, and photovoltaic inverter is required if conversion is required to 220V AC, which can be used as commercial power.

In a Magnetic Element in Photovoltaic Inverter, you'll find

1 transformer
1 common-mode inductor
2 differential mode inductors
1 filter magnetic ring

What is frequency and current conversion?

Simple transformers cannot realize AC/DC conversion and frequency conversion. With the rise of power electronics industry represented by new energy industry, more and more industries begin to use inverter circuits.

Adapter Requires Converted 
Current - Rectifier

Inverter requires conversion
Current - Inversion

Current-Inverter for Electric Vehicles to Be Converted

Current Conversion Required for Intermediate Frequency Induction Heating-Frequency Conversion

Soft Magnetic Applications Everywhere

Starting from eating:
The working principle of induction cooker is electromagnetic induction heating, which is equivalent to a small medium frequency induction heating power supply.
Automotive Electronics
Not only are there a large number of soft magnetic devices on board, but charging piles also require a large number of magnetic powder core inductors.
Medical treatment:
Nuclear magnetic resonance power supply requires at least 2 high-frequency reactors and a high-frequency tffransformer.
Transmission and distribution
Power grid distribution requires a large number of transformers, and power quality improvement requires a large number of reactors.
Wind power Generation
high frequency transformers and reactors are required.
Mobile phones, communication power supplies, computers, wireless charging, etc. require a large number of soft magnetic devices.
Household appliances
variable frequency air conditioner, water heater leakage protection switch, household electricity meter transformer, etc.
Industrial field
Inverter welding machine, ion sputtering power supply, medium frequency induction heating power supply, etc. need a large number of amorphous devices.

A typical application: power quality management, active filtering and reactive power compensation equipment as in the pictures below.

Worldwid well-known soft magnetic devices manufacturers?

ABB: Power Transformer
Siemens Hangzhou Factory: High Voltage Transformer, Sales 2 Billion
Japan TDK: From iron core products to transformer inductors, acquired Zhuhai APCOS Japan Honda Village: various inductors and transformers
South Korea SAMSUNG: Inductors, Magnetic Beads
Hitachi Metals: Inductors
Taiwan's Special Motor: reactors and transformers have now developed into many fields such as Yanshen product inverters.
Toshiba Toshiba, Japan: Early involvement in nanocrystalline magnetic rings