Market: Analysis of the Electronic Transformer Industry and New Directions in Technological Development

On the path of technological innovation, it is essential to always keep the ultimate goal in mind. For Electronic Transformers in power supplies, just like any other commercial product, any technological advancement must achieve specific functions under given usage conditions while striving for thebest cost-performance ratio.  Currently, power supply products are generally characterized by "lightweight, slim, compact, and small," evolving toward miniaturization and portability. Electronic transformers must adapt to the requirements of power supply products as used by customers regarding size and weight. Meanwhile, the prices of raw materials for electronic transformers (core materials and conductive materials) have risen. Therefore, reducing size and weight, as well as lowering costs, have become the primary directions for the development of electronic transformers in recent years.

Silicon steel is a widely used iron core material in electronic transformers in power supplies. To reduce the amount of iron core used in electronic transformers, it is necessary to increase the working magnetic flux density (working magnetic flux density) of silicon steel. The working magnetic density of silicon steel is determined by both the saturation magnetic flux density and the loss. Because efficiency is an important performance indicator of electronic transformers, many power products now require standby losses in order to save energy. The iron core loss of electronic transformers is the main component of standby loss, therefore, strict requirements are put forward for the efficiency or loss of electronic transformers.

In recent years, the prices of oriented and non oriented cold-rolled silicon steel have increased. Compared with R-type, CD type, and EI type cores, wound ring cores can save more than 20% of the cost of core materials due to their lower material consumption, expanding the scope of use of electronic transformers. The wound ring iron core can fully utilize the performance of oriented cold-rolled silicon steel, and compared with non oriented cold-rolled, the working magnetic density is much higher. Unlike R-type, CD type, and EI type iron cores, which can fully utilize silicon steel materials without corner waste, the material utilization rate can reach over 98%.

As a major category of power frequency transformers, using iron core materials with high working magnetic density can reduce the number of coil turns and copper usage without reducing the iron core cross-section and volume. In the current situation where copper prices are much higher than iron core materials, it may be a better design improvement solution.

Currently, various aluminum wires for electronic transformers in power supplies are being developed domestically. Some companies have developed copper-clad aluminum wires, with copper wire on the outer layer, accounting for 15% of the area and a total weight of 3.63g/cm3. Considering the surface effect and proximity effect, the resistivity of this copper-clad aluminum wire is much lower than that of pure aluminum wire, and the cost increase is not much. It is a composite material that fully utilizes the effects of copper and aluminum.

Another noteworthy development trend in recent years is the use of 180 polyester imine QZY enameled wire and 220 polyimide QZY enameled wire with high temperature index and heat resistance level. The allowable current density of the wire increases, the wire diameter decreases, the amount of copper used decreases, the iron core window area decreases, and the amount of iron used also decreases, which can reduce the overall cost. Especially for high-frequency and low-power Power Transformers that require small volume, using enameled wire with better heat resistance can better demonstrate technical and economic benefits.

The AC voltage conversion technology included in power technology and power electronics technology is a "pure" electronic transformer that can also convert low voltage into high voltage for boost conversion, or convert high voltage into voltage for buck conversion. Its main method is to use power electronics technology to increase the conversion frequency, thereby reducing the volume of transformers and inductors in the circuit, rather than eliminating them. Previously, the method of combining power electronic circuits with electronic transformers did not receive sufficient attention. In recent years, with the increasing demand for reducing input and output harmonics, improving grid efficiency factor, and achieving "green transformation" in the power system, research on "power electronic transformers" has been carried out both domestically and internationally, leading to a research and development boom.

Research on how to use power electronics technology to transform and control electricity, replacing traditional electromagnetic Distribution Transformers with power electronic transformers. There are now various circuit forms such as single-phase transformation and three-phase transformation.This type of power electronic transformer can be used not only in high-voltage and high current power fields, but also in high-voltage or low-voltage and low current fields, such as some high-voltage power generators and low-power voltage regulating power supplies.

There are over 2000 units engaged in research, development, and production of electronic transformers in China, including state-owned, private, and foreign-funded enterprises. The world's largest electronic transformer manufacturer, Pusi Corporation of the United States, and the world's largest soft magnetic ferrite manufacturer, TDK Corporation of Japan, both have production bases in China. Many advanced electronic transformer technologies, production processes, and products from around the world are gathered together in China. Faced with such a diverse platform, there is great potential for technical exchange.