Predictive current control based multi-pulse flexible-topology thyristor AC/DC converter and its application in wind energy conversion system

As the harmonic distortion has become a main concern due to the various nonlinear loads such as uncontrolled/controlled rectifiers being used in industry. The existing multi-pulse thyristor AC/DC converter usually has to operate in a narrow voltage range so as to obtain high power factor and low harmonic injection. This paper proposes a novel multi-pulse flexible-topology thyristor AC/DC converter (MPFTTC) that keeps low total harmonic distortion (THD) and high power factor at the point of common coupling (PCC) over a wide voltage range. Detailed analyses are carried out, including the illustration of the topology-switching mechanism which drives the MPFTTC from one operating mode to the other. In order to achieve fast current control, the predictive current control strategy is presented. A promising application of the proposed MPFTTC in the wind energy conversion system (WECS) is presented, and the control strategy of the WECS is also discussed. At the end of this paper, simulation and experiment of the laboratory prototype verify the feasibility of the MPFTTC as well as the control algorithm.