The rectifier bridge generally has a sufficiently large inductive load, so there is no current discontinuity in the rectifier bridge. Generally, when the rectifier bridge is applied, a smoothing reactor is often connected to its load end, so its load can be regarded as a constant current source. Multiple groups of three-phase rectifier bridges are connected to each other, so that the harmonics generated by the rectifier bridge circuits cancel each other out. According to the type of rectifier transformer, it can be divided into traditional multi-pulse transformer rectifier and self-coupling multi-pulse transformer rectifier. The traditional multi-pulse transformer rectifier uses an isolation transformer to isolate the input voltage and output voltage, but the equivalent capacity of the rectifier transformer is large and the volume is huge.