High-frequency Transformers: Considerations for Custom Design

The expanding demand for electronic devices is driving the need for more high-frequency transformers. SITONG has been designing and manufacturing these products since the company was founded. Our experience includes high-frequency transformers constructed from a variety of different materials, manufactured to our customers' precise specifications, and consistently delivered on time.

Transformer Design Considerations

Although they work on the same principle, the fundamental difference between high frequency transformers and standard transformers is their voltage capacity. Unlike typical 50 or 60 Hz line voltage transformers, high frequency transformers can withstand much higher voltage frequencies, typically from 20 kHz to over 1 MHz.

High voltage transformers offer many advantages, such as: highly customizable, smaller designs, less material, high power density. However, in addition to these benefits, skin and proximity effects must be carefully managed to create effective high frequency transformers.

EE High Frequency Transformer

- Leeds Wire

Leeds wire bundles thin copper wires into braided or stranded configurations to minimize skin effect by forcing current to flow more evenly throughout the wire. The design of a Leeds wire and the uniform current it provides also minimizes interference from other nearby conductors.

- Air Gap

It is also important to reduce the amount and size of the gap in the transformer core. The air gap allows the magnetic field to expand, causing proximity effects by interfering with the nearest transformer. Tape and clever structural design help minimize air gap problems and minimize proximity effects.

- Core Material

When selecting a high frequency transformer design, the transformer datasheets provide excellent tables to help you select the right core based on your calculations. Despite the presence of a hollow core, the most typical core for a high frequency transformer will consist of a powdered ferrite substance called ferrite.

Ferrite cores combat many of the undesirable effects that plague high frequency transformers. They have very low core losses and minimal eddy current losses. When selecting a core, it is also possible to start with a core weight or core volume based on the transmitted power and switching frequency, and then select the most suitable core in this manner.

- Cooling

Small, dense transformers require continuous cooling to prevent the system from overheating. Designing small transformers with cooling plates or fans has become a necessity for a variety of applications. Transformers can also be encapsulated in thermally conductive materials to dissipate unwanted heat.

- Turning

Once a suitable core has been selected, the designer can calculate the number of primary turns of the transformer. Since the term "high frequency" spans a variety of frequency levels, and specific applications may or may not need to accommodate certain ranges. Knowing the number of turns determines the flux density present in the core. With all of these factors, topologies can be selected and designs can be shaped.

- Output Type

When selecting an output, you will have both alternating current (AC) and direct current (DC) options. While AC is usually given in RMS values, you will need to discuss the type of DC rectification with your designer.

There are several types of high voltage power transformers, so consult your designer to find out how a high voltage transformer can meet the specific requirements of your application.

EPC Flyback Transformer

Applications

The small size of high frequency transformers makes them valuable in a variety of large or small applications. Common applications include, but are not limited to

Consumer electronics

Medical equipment

Renewable energy

Robotics

Motor drives

Ozone Devices

Battery chargers

UPS

Rail

Select SITONG

Requirements for transformers can vary widely and standard solutions may not be suitable for all applications. SITONG offers the ability to design custom high frequency transformers in the range up to 500 kHz.However, frequency is not the only factor to consider when customizing a transformer.

Our team is equipped with a full suite of state-of-the-art equipment to design and manufacture any type of standard or high frequency transformer required by our customers. For more information or to request a quote, please contact us today.