Natural frame-based strategy for vienna-type rectifier with light unbalanced input voltages

When the Vienna-type rectifier works at unbalanced input operation conditions, the dc-link voltage ripples and the dc component of the reactive power will be introduced. Therefore a novel control scheme based on natural frame is proposed. The fundamental positive-/negative-sequence voltage components are derived by applying an early developed direct decoupled synchronisation method. A natural abc frame-based current control loop, which considerably reduces total algorithm complexity and also helps to reduce the reactive components size and total loss in comparison with the traditional dual current control schemes, is proposed based on the mathematical modelling of Vienna rectifier under unbalanced input conditions. In addition, the static operation region of the Vienna-type rectifiers is analysed and derived. Finally, the experimental results are given to verify the effectiveness of the proposed control scheme and the conclusion. Performance comparison between the traditional controller and proposed controller is demonstrated by the experimental results.