Diode Bridge Rectifier with Improved Power Quality Using Capacitive Network

Widely distributed single-phase power electronic rectifier loads are increasing source of harmonics in power distribution system. These harmonics have many well known adverse impacts on the power system. So it is necessary to improve the power quality of the rectifiers. This paper presents a novel single phase rectifier in which capacitors are used in parallel with diodes in one leg of the rectifier. A general analytical model of the proposed topology is obtained. The closed form expressions for the rectifier waveforms helps in parameter selection that leads to optimal performance in terms of input current THD. A comparative study of different topologies of rectifiers are done in terms of input voltage, current waveform distortion, output dc voltage ripple, and desired target for dc output voltage. The proposed topology reduces the total harmonic distortion from 145 percent in normal rectifier to 63 percent while maintaining voltage ripple less then 0.3 percent. The proposed topology keeps dc bus ripple small while simultaneously providing better THD. The passive components considered for improving harmonic injection are 2 small capacitors. The additional cost required for the proposed rectifier is low, the proposed rectifier also has a higher efficiency than the other commonly used topologies