High Frequency Transformer Copper Loss Of The Coil
High Frequency Transformer Copper loss of the coil
The DC loss of the high frequency transformer is caused by the copper loss of the coil. To improve efficiency, should try to choose the thicker wire, and take the current density J = 4 ~ 10A / mm2.
The AC loss of the high frequency transformer is caused by the skin effect of the high frequency current and the loss of the core. High-frequency current through the wire always tends to flow from the surface, which will reduce the effective flow of the wire area, and the equivalent impedance of the wire is much higher than the copper resistance. High-frequency current on the penetration of the conductor and the switching frequency of the square root is inversely proportional to reduce the AC copper impedance, wire radius must not exceed the high frequency current up to 2 times the depth. Available wire diameter and switching frequency of the curve. For example, when f = 100kHz, the wire diameter is theoretically desirable φ0.4mm. But to reduce the skin effect, more fine wire and more than around, rather than a thick wire around the system. In the design of high-frequency transformer to minimize leakage inductance. The greater the leakage inductance, the higher the peak voltage amplitude, the greater the loss of the drain clamp circuit, which is necessarily reduced power efficiency. A high-frequency transformer that conforms to the insulation and safety standards, the leakage inductance should be 1% to 3% of the primary inductance of the secondary open circuit. Three-core high-voltage transformer is commonly used in electronic products, electronic equipment, is used to low-frequency low-voltage low-frequency high-voltage electromagnetic induction equipment. When the primary winding through the alternating current, the transformer produces alternating magnetic field, through the alternating magnetic field induction, the secondary winding also produces alternating magnetic field and produce alternating electromotive force, the secondary winding voltage and secondary winding turns The relationship between the voltage and the number of turns is proportional to the high pressure of the main role is to convert low voltage into the required high voltage insulation in the production process is particularly important, many manufacturers of product quality is not reflected in the insulation processing, Good insulation is the most important high-voltage transformer production. Transformer voltage regulator system with on-load voltage and no load regulator two. On-load voltage regulator is: the transformer can be adjusted in the operation of the transformer tap position, thus changing the transformer ratio, in order to achieve the purpose of regulation. There are two ways of adjusting the voltage regulator and the neutral point in the on-load tap-changer, that is, the difference between the transformer tap end on the high winding end or the neutral side of the high voltage winding. The tap can reduce the insulation level of the transformer tap at the neutral point, with significant superiority, but requires that the neutral point of the transformer must be directly grounded during operation.
On-load voltage regulator and no load regulation, on-load tap-changer is in the case of load, transform the transformer tap, in order to achieve the purpose of regulating the voltage. No excitation voltage regulator, not the transformer without the second load, but the transformer side are off with the power grid, in the transformer without excitation under the circumstances of the winding transformer tap. On-load voltage regulator and no-load regulator, on-load regulator is generally 19 files, each file 1.25%, no load regulator each file is generally 1.5% or 2.5%. No load regulator to stop the transformer, no load.
Transformer non-excitation tap-changer of the rated voltage range is narrow, less adjustment level. The rated voltage range is expressed as ± 5% or ± 2 × 2.5% of the rated voltage of the transformer.
General large-scale power transformers are used on-load tap-changer, small distribution transformers are generally no load.