In the past 30 years, almost all kinds of electronic products are developing in the direction of high frequency, high efficiency, low loss and high cost performance, making the living space of traditional EI and C type magnetic core electronic transformers narrower and smaller. Therefore, in the case of the traditional electronic transformer production in China, it is necessary to increase the pace of its replacement in the spirit of reform and innovation, otherwise, the electronic transformer industry in the mainland will be in the position of "working" for a long time.
In a sense, China's electronic transformer industry is experiencing three levels of renewal:
The first level is the innovation of the three-dimensional transformer to the planar transformer, the volume weight of the planar transformer is reduced by 80% than the traditional type, and the product series of 5W-20kW/20kHz ~ 2MHz has been formed, and the typical value of its efficiency can reach 98%.
The second level of renewal is the mass production of chip transformers. The height of the chip transformer is further reduced, and the flattening is basically achieved. They are suitable for the requirements of low-voltage and high-current power supplies with currents above 100A. Its structure generally uses a primary winding multiple core instead of the traditional one core multiple winding.
The third level update is the successful development and design of thin film transformer. Due to the use of thin film structure, the low height is better realized, generally less than 1mm, and the operating frequency exceeds 1MHz, up to 10 MHz ~ 100MHz. Thin film transformer can be manufactured by integrated circuit process, so the cost is not higher than the chip transformer, thin film transformer is the development direction of the widely used DC switching power transformer.
From the perspective of use, the design of electronic products is more and more personalized and diversified, and there are many categories, varieties and models. The design and manufacture of electronic transformer must adapt to this trend and principle. At present, the design and manufacture of electronic transformers must pay attention to the following requirements:
1, structural design, the general trend is small, thin and light, suitable for SMT installation requirements. For electronic transformer designers, small, thin and light is the most difficult of the three passive components. In order to meet the requirements of miniaturization indicators, the preferred measure is to increase the working frequency of the power supply, and the current working frequency is more than 20kHz ~ 100MHz. The choice of high operating frequency, followed by the increase of high-frequency loss and electromagnetic noise, which requires the use of new high-end magnetic materials and anti-electromagnetic interference devices to overcome, which will complicate the design of electronic transformers and power supplies.
2, electronic transformer design should put the work efficiency and production efficiency in an important position. Improving the working efficiency and production efficiency of electronic transformers is the specific implementation of environmental protection and energy saving. In the design of electronic transformers, the required working efficiency is: the efficiency of low-power DC switching power supply below 100W is >85%; The working efficiency of medium and high power DC switching power supply should be greater than 90%. The loss of electronic transformers and inductors accounts for about 15% of the power supply, so the working efficiency of electronic transformers is required to be >95% ~ 98%. The no-load loss and no-load current of the electronic transformer are the main factors of the standby loss of electronic equipment, therefore, the no-load loss of the electronic transformer is required to be less than 2%. The design to improve the working efficiency of electronic transformers must also solve the problem of less heat and fast heat dissipation.
3, like any other product, cost is an issue that electronic transformer design must face. In addition to adapting to the requirements of modern electronic equipment in terms of low loss, small size, high efficiency, stability and reliability, low price is a necessary condition for market competition. To reduce the cost of transformers, design is the foundation. The use of raw materials and structural form play a leading role in the cost of design, process equipment and process design, online test equipment and route design, etc., should be based on the lowest cost.
4, in the case that some materials have risen in price and remain at a high price, find some lower-priced materials to replace, such as replacing copper wires with copper-clad aluminum wires.
