Multipulse Diode Rectifiers

This chapter focuses on the separate‐type multipulse rectifiers, where each of its six‐pulse rectifiers feeds a separate DC load. The main feature of the multipulse rectifier lies in its ability to reduce the line current harmonic distortion. This is achieved by the phase‐shifting transformer, through which some of the low‐order harmonic currents generated by the six‐pulse rectifiers are canceled in the transformer primary winding. The multipulse rectifier has a number of other features. It normally does not require any load commutated (LC) filters or power factor compensators, which leads to the elimination of possible LC resonances. The multipulse diode rectifiers can be classified into two types: series‐type multipulse rectifiers, where all the six‐pulse rectifiers are connected in series on their DC side and separate‐type multipulse rectifiers, where each of the six‐pulse rectifiers feeds a separate DC load.