Analysis of Harmonic Cancellation Performance of a Shunt Phase-Shift Transformer Rectifier

A 12-pulse rectifier has been widely used for harmonic mitigation in a large-scale power system. Recently, a shunt phase-shift transformer rectifier was proposed and already has been utilized in a marine transportation. For a power system equipped with multiple generators, the shunt phase-shift transformer front-end selectively eliminates 5^th and 7^th harmonic component with more than 75% size reduction over the conventional 12-pulse rectifier. However, a shunt phase-shift transformer rectifier requires additional source inductors to eliminate the undesired harmonics and the relationship between the source impedance and harmonic elimination has not been verified. This paper evaluates the effect of the line inductor on a harmonic cancellation performance of the shunt phase-shift transformer. An equivalent circuit analysis and a mathematical derivation of the shunt phase-shift transformer rectifier are provided and the relationship between the source impedance and harmonic cancellation is mathematically derived. The computer simulation and experimental test results from proto type hardware verify the equivalent model and the mathematical analysis.