Article

An Improved Power-Quality 30-Pulse AC–DC for Varying Loads

Dept. of Electr. Eng., Indian Inst. of Technol., New Delhi
IEEE Transactions on Power Delivery (Impact Factor: 1.73). 05/2007; 22(2):1179 - 1187. DOI: 10.1109/TPWRD.2007.893615
Source: IEEE Xplore

ABSTRACT

This paper presents the design and analysis of a novel 30-pulse ac-dc converter for harmonic mitigation under varying loads. The proposed 30-pulse ac-dc converter is based on a polygon-connected autotransformer with reduced magnetics. The proposed ac-dc converter is able to eliminate lower than 29th order harmonics in the ac supply current. The resulting supply current is near sinusoidal in shape with low total harmonic distortion and a nearly unity power factor. Moreover, the design of an autotransformer is modified to make it suitable for retrofit applications, where presently a 6-pulse diode bridge rectifier is used. To validate the proposed approach, various power-quality indices are presented under varying loads. The proposed ac-dc converter is found to be suitable for retrofit applications with a large load variation and where harmonic reduction is more stringent. The laboratory prototype of the proposed autotransformer-based 30-pulse ac-dc converter is developed and test results are presented which validate the developed design procedure and the simulation models of this ac-dc converter

11 Followers
 · 
90 Reads
  • Source
    • "Accordingly, 30-pulse autotransformer based AC-DC converter and 36-pulse configuration have been presented in [22] and [23], respectively. Current THD varies between 2.63% and 3.71% (for light loads) for the 30-pulse converter and between 2.038% and 3.748% for the 36-pulse converter schematics. "
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents a pulse doubling technique in a 36-pulse ac-dc converter which supplies direct torque-controlled motor drives (DTCIMD's) in order to have better power quality conditions at the point of common coupling. The proposed technique increases the number of rectification pulses without significant changes in the installations and yields in harmonic reduction in both ac and dc sides. The 36-pulse rectified output voltage is accomplished via two paralleled eighteen-pulse ac-dc converters each of them consisting of nine-phase diode bridge rectifier. A transformer is designed to supply the rectifiers. 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. Independent operation of paralleled diode-bridge rectifiers, i.e. dc-ripple re-injection methodology, requires a Zero Sequence Blocking Transformer (ZSBT). Finally, a tapped interphase reactor is connected at the output of ZSBT to double the pulse numbers of output voltage up to 72 pulses. 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 operation. A comparison is made between 6-pulse, 36-pulse, and proposed converters from view point of power quality indices. Results show that input current total harmonic distortion (THD) is less than 3% for the proposed topology at variable loads.
    Full-text · Article · Feb 2012 · Archiwum Elektrotechniki
  • Source
    • "Accordingly, 30-pulse autotransformer based AC-DC converter and 36-pulse configuration have been presented in [24] and [25], respectively which Current THD is less than 5% for varying loads. The need of 30 and 36 diodes in the presented topologies of [24] and [25] respectively, is not economical. The Polygon-Connected Autotransformer-Based 40- pulse [26] was designed for VCIMD's loads which Current THD is less than 5% for varying loads. "
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents a pulse doubling technique in a 20-pulse ac-dc converter which supplies direct torque controlled motor drives (DTCIMD’s) in order to have better power quality conditions at the point of common coupling. The proposed technique increases the number of rectification pulses without significant changes in the installations and yields in harmonic reduction in both ac and dc sides.The 20-pulse rectified output voltage is accomplished via two paralleled ten-pulse ac-dc converters each of them consisting of five-phase diode bridgerectifier. A transformer is designed to supply the rectifiers. The design procedure of magnetics is in a way such that makes it suitable forretrofit applications where a six-pulse diode bridge rectifier is being utilized. Independent operation of paralleled diode-bridge rectifiers, i.e. dc-ripple re-injection methodology, requires a Zero Sequence Blocking Transformer (ZSBT). Finally, a tapped interphase reactor is connected at the output of ZSBT to double the pulse numbers of output voltage up to 40 pulses. 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 fora wide range of DTCIMD operation. A comparison is made between 6-pulse, 20-pulse, and proposed converters from view point of power quality indices. Results show that input current total harmonic distortion (THD) is less than 5% for the proposed topology at various loads.
    Full-text · Article · Jan 2012 · Przeglad Elektrotechniczny
  • [Show abstract] [Hide abstract]
    ABSTRACT: Three-phase multipulse AC-DC converters (MPC) are developed for improving power quality to reduce harmonics in AC mains and ripples in DC output. This paper deals with the multipulse AC-DC converter configurations, state of art, their performance, power quality aspects, components selection considerations, latest trends, future developments, and potential applications. It is targeted to provide broad perspective on multipulse converter technology to the researchers, engineers, and designers dealing with them. A classified list of more than 250 research publications on the subject is also given for quick reference.
    No preview · Article · Feb 2008 · IEEE Transactions on Power Electronics
Show more