Rectifier transformers are used to convert alternating current (AC) to direct current (DC) in various applications, such as industrial power supplies, traction systems, and electrochemical processes. The process of rectification involves changing the direction of current flow in the circuit, and transformers are used to step down or step up the voltage level of the AC power supply.

One of the challenges of rectifier transformers is the generation of harmonics in the output voltage waveform. Harmonics are the multiples of the fundamental frequency and can cause unwanted effects such as increased losses, electromagnetic interference, and distortion of the waveform. To reduce the harmonic content in the output voltage, a technique called pulse rectification can be used.

In pulse rectification, the input AC voltage is split into multiple phases, and each phase is rectified separately using a diode bridge. By using multiple phases, the waveform of the output DC voltage can be made smoother, with less harmonic content. The number of phases used in the rectification process is called the pulse number, and it is determined by the number of diode bridges used in the circuit.

The most common pulse numbers used in rectifier transformers are 6-pulse, 12-pulse, and 24-pulse. The 12-pulse and 24-pulse configurations are achieved by using two and four sets of diode bridges, respectively, and they offer improved waveform quality compared to the 6-pulse configuration.

In a 12-pulse rectifier, the input voltage is split into two phases, each of which is rectified by a diode bridge. The two phases are out of phase by 30 degrees, and this helps to reduce the harmonic content in the output voltage. In a 24-pulse rectifier, the input voltage is split into four phases, with each phase rectified by a separate diode bridge. The phases are arranged such that the current from each phase is shifted by 15 degrees from the adjacent phase, resulting in even lower harmonic content in the output voltage.

In conclusion, rectifier transformers are essential components in many power systems, and the use of pulse rectification can help to improve the quality of the output voltage waveform. The choice of pulse number depends on the specific application and the level of harmonic content that is acceptable. The 12-pulse and 24-pulse configurations are commonly used for their improved waveform quality compared to the 6-pulse configuration, and they are particularly useful in applications where low harmonic distortion is important.

LuShan, est. 1975,  is a Chinese professional manufacturer specializing in power transformers and reactors for 48 years. Leading products are single-phase transformer, three-phase transformers, DC inductors, AC reactors, filtering reactor, expoxy resin high-voltage transformer and intermediate, high-frequency products. Our transformers and reactors are widely used in 10 application areas: rapid transit, construction machinery, renewable energy, intelligent manufacturing, medical equipment, coal mine explosion prevention , excitation system, vacuum sintering, central air conditioning.

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