Virtual flux model predictive direct power control (VF-MPDPC) of afe rectifier with new current prediction method and negative sequence elimination

Abstract

In this paper a simple method is presented in order to control a three-phase active front end (AFE) rectifier under both balanced and unbalanced network voltage conditions which consists in virtual flux based model predictive direct power control (VF-MPDPC) with a new approach on the current and power prediction. A new approach for current prediction in the unbalanced condition is proposed. The prediction procedure of the proposed method is simpler than that of the previous methods. Moreover, the influence of the negative sequence component of the grid voltage on the calculated virtual flux is compensated by using a band stop filter in orthogonal coordination. This leads to low THD of the input currents and also the unity power factor is achieved even in the network malfunction condition. Also, the method makes it possible to use the simplified balanced condition equations in the network unbalanced condition. The proposed method is verified by simulations.