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High Frequency Transformer The Design Principle And Use

May 27, 2017

  High Frequency Transformer High-frequency transformer is the operating frequency of more than IF (10kHz) power transformer, mainly used for high-frequency switching power supply for high-frequency switching power supply transformers, but also for high-frequency inverter and high-frequency inverter welding machine for high-frequency reverse Variable power transformer. According to the operating frequency level can be divided into several grades: 10kHz ~ 50kHz, 50kHz-100kHz, 100kHz ~ 500kHz, 500kHz ~ 1MHz, 10MHz or more.

  High Frequency Transformer Transformer is the exchange of AC voltage, current and impedance of the device, when the primary coil with AC current, the core (or core) will produce AC flux, so that the secondary coil induced voltage (or current).

  Transformer consists of iron core (or core) and coil, the coil has two or more than the winding, which connected to the power supply winding called the primary coil, the rest of the winding called secondary coil.

  High-frequency transformer is the operating frequency of more than IF (10kHz) power transformer, mainly used for high-frequency switching power supply for high-frequency switching power supply transformers, but also for high-frequency inverter and high-frequency inverter welding machine for high-frequency reverse Variable power transformer. According to the working frequency level, can be divided into several grades: 10kHz ~ 50kHz, 50kHz-100kHz, 100kHz ~ 500kHz, 500kHz ~ 1MHz, 1MHz or more. Transmission power is relatively large, the power devices generally use IGBT, IGBT due to the existence of off-current phenomenon, so the operating frequency is relatively low; transmission power is relatively small, you can use MOSFET, the operating frequency is relatively high.

  High Frequency Transformer In the design of high-frequency transformers, the leakage inductance and distributed capacitance of the transformer must be minimized because the high-frequency transformer in the switching power supply transmits the high-frequency pulse square wave signal. In the transmission of the transient process, the leakage inductance and distributed capacitance will cause inrush current and peak voltage, and the top of the oscillation, resulting in increased wear and tear. Usually the transformer leakage inductance, control for the primary inductance of 1% to 3%.

The leakage inductance of the primary coil - the leakage inductance of the transformer is due to the primary coil and the secondary coil, between the layer and the layer, between the turns and the flux is not fully coupled between the resulting.

Distribution capacitor ---- Transformer winding between the turns, the same winding between the lower, between the different windings, between the winding and the formation of the capacitor called the distributed capacitance.

The primary winding - the primary winding should be placed in the innermost layer, which minimizes the length of each turn of the primary winding of the transformer, thus minimizing the use of the entire winding, which effectively reduces the distribution of the primary winding itself capacitance.

Secondary winding ---- primary winding around, to add around (3 ~ 5) layer of insulation pads and then winding the secondary winding. This reduces the capacitance of the distributed capacitance between the primary and secondary windings, and increases the dielectric strength between the primary and the secondary, meeting the insulation withstand voltage requirements.

Bias winding - bias winding around the primary and secondary, or around the outermost layer, and the switching power supply is adjusted according to the secondary voltage or the primary voltage