Three phase passive bridge rectifier with low distortion input current and boosted DC output voltage

This paper presents a new combined design of a passive series LC filter with a 3-phase diode bridge rectifier using three capacitors at the input of the bridge rectifier to boost the dc output voltage without the need for active switching devices. Therefore the rectifier can be use for machine drives without requiring machine de-rating or overmodulation techniques. The input inductor/capacitor filter works to reduce the harmonics current even if the applied ac voltage is already distorted, while the bridge capacitors improve the input power factor. This configuration minimizes the 5^th and 7^th current harmonics without increasing higher order harmonics, resulting in a total harmonic distortion of less than 2%. At medium and high power levels the rectifier operates at nearly unity power factor. In the paper a comparison is made between a number of three phase diode bridge rectifier topologies with passive networks, and it is shown that the new design outperforms other circuits in all aspects. The operation of the new three phase diode bridge rectifier topology is illustrated by simulation results, which are confirmed by experimental data.