T-Connected Multi-Pulse AC-DC Converters for Power Quality Improvement

This book presents the design and analysis of T-Connected autotransformer based multipulse ac-dc converters which supplies a direct torque controlled motor drive in order to improve power quality conditions at the point of common coupling. A T-connected autotransformer is designed to supply the rectifiers. This autotransformer makes use of only two single-phase transformers, resulting in reduced volume, weight, and the cost of the drive as compared with polygon structure. The design procedure of magnetics is in a way such that makes it suitable for retrofit applications where a six-pulse diode bridge rectifier is being utilized.The aforementioned structure improves power quality criteria at ac mains and makes them consistent with the IEEE-519 standard requirements for varying loads. Furthermore, near unity power factor is obtained for a wide range of DTCIMD load operation. A comparison is made between 6-pulse, 28-pulse, 30-pulse, and 36-pulse converters from view point of power quality indices. Results show that the THD of input current is less than 5% for the 28-pulse topology and less than 3% for the 30-pulse topology and less than 4% for the 36-pulse topology at variable loads.

Autorentext

Rohollah. Abdollahi was born in Qom, Iran, in 1983. He received the M.Sc. degree in power electronics and electrical machines from Iran University of Science and Technology, Tehran, Iran, in 2011. He joined the Qom Branch, Islamic Azad University, Qom, Iran.He is the author of more than 20 journal and 5 conference papers and 8 Patents.