A Novel 36-pulse Rectifier with a Delta-Configured Pulse-Doubler Circuit

To enhance the harmonic suppression capability of the traditional 18-pulse rectifier, a Delta-configured pulse doubler circuit (DC-PDC) is proposed, and a new 36-pulse rectifier with DC-PDC is presented in this paper. The DC-PDC consists of three dual-tapped converters and is installed on the DC side of the rectifier. The positive output terminals of three rectifier bridges serve as the input to the DC-PDC, and the output of the DC-PDC is connected to the load to supply power. The unique structure and connection method of the DC-PDC enable six auxiliary diodes to conduct cyclically, thereby increasing the output states of the rectifier bridges. This effect, in turn, increases the pulse number of the rectifier from 18 to 36, reducing the total harmonic distortion of the input current from 7.1% to 2.4%. The proposed scheme requires only a purely passive DC-PDC with a low KVA rating (7.35% Pd). It offers advantages, such as a simple circuit structure, easy implementation, high reliability and low cost. A 1.5 kW prototype was built to verify the theoretical analysis.