Difference between rectifier transformer and power transformer
Writer： Hengfeng you electric Time：2023-05-09 views：times
Converter is the general name of rectifier, countercurrent and frequency conversion. Rectifier is the most widely used one. The characteristic of rectifier equipment is to output the input AC into DC after rectification and filtering. Rectifier transformer is the power transformer of rectifier equipment. Most industrial rectifier DC power supplies are obtained by rectifier transformer and rectifier equipment.
What is a power transformer
Power transformer generally refers to the transformer that supplies power to the electric drive system. Most of the transformers in the power grid are power transformers.
Difference between rectifier transformer and power transformer
1、 Functional difference
Functions of rectifier transformer:
1）. Is to supply appropriate voltage to the rectifier system;
2）. It is to reduce the pollution of power grid caused by waveform distortion caused by rectifier system.
The output of rectifier transformer is still AC, which only provides power for rectifier equipment. Usually, the primary side is connected into a star shape and the secondary side is connected into an angle shape to suppress high-order harmonics. The secondary side is connected into an angle and the neutral point is not grounded. When the rectifier equipment is grounded at one point, it will not cause equipment damage. The grounding fault alarm signal will be sent out through the grounding detection equipment. 1、 Shielding isolation is added between the secondary.
Rectifier transformers are mainly used in electrolysis, smelting, excitation, transmission, cascade speed regulation, electrostatic dust removal and high-frequency welding. The structure is a little different. In order to make the waveform smooth, some rectifier transformers for electrolysis are made into six phase output, and a six phase rectifier bridge is added outside to get a relatively smooth waveform. According to the current waveform characteristics and anti harmonic requirements of silicon controlled rectifier circuit for smelting and high-frequency welding, the eddy current loss in rectifier transformer winding and stray loss in structural parts are optimized for some data and processes. In fact, the general structure is also similar.
The power transformer is usually Y / y connected neutral grounding (providing single-phase power supply). If it is used for rectifier equipment, the rectifier equipment will be damaged in case of grounding fault. Moreover, its ability to suppress high-order harmonics generated by rectifier equipment is also poor.
2、 Different uses
The transformer used as the power supply of rectifier is called rectifier transformer. Most of the rectifier DC power supply used in industry is obtained by the rectifier equipment composed of rectifier transformer and rectifier in AC power grid. In today's highly modern society, its great use can be seen directly or indirectly in almost every field. Power transformer is mainly used for power system, daily lighting and factory power.
The main purposes of rectifier transformer are as follows:
1）. Electrochemical industry;
2）. DC power supply for traction;
3）. DC power supply for transmission;
4）. DC power supply for DC transmission;
5）. DC power supply for electroplating or machining;
6）. DC power supply for excitation;
7）. DC power supply for charging;
8）. DC power supply for electrostatic precipitator;
3、 Output voltage difference
1) Differences in address:
Due to the close combination with rectifier, the output voltage of rectifier transformer is called valve side voltage. Its name comes from the unidirectional conductivity of diodes.
2) Differences in calculation methods:
The calculation method of the output current is different from that of the rectifier circuit, and the calculation method of the output current is also very different from that of the transformer.
4、 Differences in design and manufacturing
Due to the difference between rectifier transformer and power transformer in use, it is also very different from power transformer in design and manufacturing: considering the working condition of rectifier transformer, rectifier transformer has achieved low current density and magnetic flux density; The impedance is also slightly larger. In terms of winding structure, the valve side sometimes requires two windings to supply forward and reverse transmission or forward transmission and reverse braking respectively. When braking, the converter is in the inverter working state; If the transformer has harmonic requirements, a shielding layer with grounding terminal shall be placed between the windings; Strengthen the pressing plate and brace, increase the oil passage and other measures to improve the short-circuit resistance of the winding; In addition, in terms of heat dissipation, there is usually a greater margin than that considered in the design and manufacture of power transformers.
