Working Principle of Rectifier Transformer

In the chemical industry with the most application of rectifier, high-power rectifier devices have low secondary voltage and high current, so they are similar to electric furnace transformer in many aspects, that is, the structure characteristic points mentioned above, rectifier transformer also has. The biggest characteristic of rectifier transformer is that the secondary current is not sinusoidal AC. Because of the unidirectional conduction characteristic of the following rectifier elements, each phase line is no longer at the same time with load current but with soft current conduction. The pulsating current in one direction is transformed into direct current through the filter device. The secondary voltage of rectifier transformer is not only related to the capacity connection group, such as the commonly used three-phase bridge rectifier circuit. The secondary voltage and current of the rectifier transformer with double inversion and balanced reactor are different for the same DC output voltage and current. Therefore, the parameter calculation of the rectifier transformer is based on the rectifier circuit, and the general parameter calculation is from the secondary side to the primary side.

Because the rectifier winding current is non-sinusoidal and contains many high-order harmonics, in order to reduce the harmonic pollution to the power grid, in order to improve the power factor, it is necessary to increase the pulse wave number of rectifier equipment, which can be solved by phase-shifting method. The purpose of phase shifting is to make a phase shift between the same terminal voltage of the secondary winding of rectifier transformer.