Voltage sensorless model predictive control for AC/DC matrix converters

Abstract

This paper proposes a virtual-flux-based model predictive control (VF-MPC) scheme to remove the grid voltage sensor and enhance the grid current performance for AC/DC matrix converter under unbalanced grid voltages. By modelling the power flow in terms of the virtual flux (VF) and its 90° lagging signal, the grid current reference and grid voltage are obtained simply without the extraction of the VF positive and negative sequence components. Furthermore, the number of current vectors is increased from 9 to 39 vectors by generating 30 virtual current vectors to minimise the grid current tracking error. Especially, to reduce the computational burden due to the increased number of current vectors, we introduce a simple sector detection algorithm, which can effectively reduce the number of candidate current vectors from 39 to 8. The proposed VF-MPC scheme is compared with previous MPC schemes, and the control effectiveness is verified by simulation and experimental results.