The structure of the power transformer
A power transformer is a device that changes 50Hz or 60Hz alternating current to direct current. It is commonly used in the power supply of electronic devices.
1. Classification of power transformers:
According to the use can be divided into: rectifier transformer and voltage regulator transformer; According to the voltage level can be divided into: single phase, three phase and polyphase transformer; According to the cooling method, there are dry transformer and oil immersed power transformer.
2, the structure of the power transformer:
(1) Rectifier:
It is a circuit element with an output voltage of 0V (negative). It consists of an input terminal, an output terminal and an intermediate tap. Its function is to convert 220VAC AC into DC voltage. The main component of the rectifier is the diode (D1), which adjusts the output current through the current control electrode resistance.
(2) Filter:
The circuit element that acts as a filter between the rectifier and the load is called the filter (F). It is composed of capacitor C1, inductor L1 and resistor R2. Its main function is to reduce the influence of pulsating current on electrical equipment and prevent the generation of harmonic interference. Due to the existence of a large number of harmonic components in the power grid, for example, the sine wave with power frequency of 50Hz contains the fundamental wave component about 100 times/second, the frequency of the square wave of 50Hz is about 40000HZ, the frequency of the sine wave of 100khz is more than 200000HZ, the frequency of the sine wave of 1000khz is about 50000 times/second, and so on.
(3) Inverter:
Is to convert direct current into mains power conversion device called inverter (PFC). It is used to convert the DC electric energy provided by the battery into AC electric energy for the load.
(4) Power factor correction:
The power factor is the ratio of the output power to its rated output power. It is generally believed that the generator has good economy when the power factor is greater than 0.95. Currently, 0.85 ~ is commonly used
