The Best High Frequency Transformer Manufacturer in China

FKS CoilS is one of the major manufacturers specializing in the development, production, sales, and processing of high-frequency transformers. The production and management team has more than 15 years of experience in the high-frequency electronic transformer industry. The main products are: Power Transformers, SMD Inductors, Inductors, Instrument /Current, Switching Transformers, Toroidal Power Transformers, Audio Balun, Balanced Isolation, Telecom/Datacom and so on.

Mainly used in: electronic power supply, industrial control, test and measurement, avionics, medical, military, characteristic and educational products.

FKS CoilS mold development and design capacity is more than 25 sets per month, combined with professional R&D strength, high-quality product quality, high-quality management team, providing customers with a monthly production capacity of more than 50 million.

Definition of High Frequency Transformer

High-frequency transformer is a power transformer whose operating frequency exceeds intermediate frequency (10kHz). It is mainly used as a high-frequency switching power transformer in high-frequency switching power supplies, and is also used as a high-frequency inverter in high-frequency inverter power supplies and high-frequency inverter welding machines. power transformer. According to the working frequency, it can be divided into several grades: 10kHz-50kHz, 50kHz-100kHz, 100kHz-500kHz, 500kHz-1MHz, and above 10MHz.

High-frequency transformer is the most important component of switching power supply. There are many topologies in switching power supplies. For example, a half-bridge power conversion circuit, when working, two switching transistors are turned on in turn to generate a high-frequency pulse wave of 100kHz, and then the voltage is transformed through a high-frequency transformer to output alternating current, and the ratio of turns of each winding coil of the high-frequency transformer is determined. the output voltage. The most conspicuous in a typical half-bridge transformer circuit are three high-frequency transformers: main transformer, drive transformer and auxiliary transformer (standby transformer). Each transformer has its own measurement standard in national regulations, such as the main transformer, As long as it is a power supply above 200W, the core diameter (height) must not be less than 35mm. As for the auxiliary transformer, when the power supply does not exceed 300W, its magnetic core diameter is enough to reach 16mm.

Working Principle

A transformer is a device that transforms AC voltage, current, and impedance. When an AC current passes through the primary coil, an AC magnetic flux is generated in the iron core (or magnetic core), which induces a voltage (or current) in the secondary coil.

The transformer consists of an iron core (or magnetic core) and a coil. The coil has two or more windings. The winding connected to the power supply is called the primary coil, and the remaining windings are called the secondary coil.

Design Principle

When designing a high-frequency transformer, the leakage inductance and distributed capacitance of the transformer must be minimized, because the high-frequency transformer in the switching power supply transmits a high-frequency pulse square wave signal. During the transient process of transmission, leakage inductance and distributed capacitance will cause surge current and peak voltage, as well as top oscillation, resulting in increased loss. Usually the leakage inductance of the transformer is controlled as 1% to 3% of the primary inductance.

Leakage inductance of the primary coil - The leakage inductance of the transformer is caused by the incomplete coupling of the magnetic flux between the primary coil and the secondary coil, between layers, and between turns.

Distributed capacitance--the capacitance formed between the turns of the transformer winding, between the upper and lower layers of the same winding, between different windings, and between the winding and the shielding layer is called distributed capacitance.

Primary winding--the primary winding should be placed in the innermost layer, so that the wire length of each turn of the primary winding of the transformer can be the shortest, so that the entire winding wire is the least, which effectively reduces the distribution of the primary winding itself capacitance.

Secondary winding - After the primary winding is wound, (3-5) layers of insulating pads should be added and then the secondary winding should be wound. In this way, the capacitance of the distributed capacitance between the primary winding and the secondary winding can be reduced, and the insulation strength between the primary and secondary windings can be increased, meeting the requirements of insulation withstand voltage.

Bias winding - whether the bias winding is wound between the primary and secondary, or wound on the outermost layer, is related to whether the adjustment of the switching power supply is based on the secondary voltage or the primary voltage.

Usage

High-frequency transformer is a power transformer whose operating frequency exceeds intermediate frequency (10kHz). It is mainly used as a high-frequency switching power transformer in high-frequency switching power supplies, and is also used as a high-frequency inverter in high-frequency inverter power supplies and high-frequency inverter welding machines. power transformer. According to the working frequency, it can be divided into several grades: 10kHz-50kHz, 50kHz-100kHz, 100kHz-500kHz, 500kHz-1MHz, and above 1MHz. When the transmission power is relatively large, the power device generally adopts IGBT, because the IGBT has the off-current tailing phenomenon, so the operating frequency is relatively low; when the transmission power is relatively small, MOSFET can be used, and the operating frequency is relatively high.