Model Predictive Direct Power Control for grid-connected converters

Abstract

This paper presents a Model Predictive Direct Power Control (MPDPC) scheme for the control of three-phase grid-connected Voltage Source Converters (VSCs). MPDPC builds on the well-known Direct Power Control (DPC) scheme by utilising a state-space model of the system to predict the future behaviour of the system. MPDPC achieves optimal performance by minimising the switching losses or switching frequency of the converter while regulating the output real and reactive powers. The scheme presented here utilises the Virtual Flux (VF) estimation technique which enables accurate estimation of the output real and reactive power without the use of line-voltage sensors. Through simulation, it is shown that at a fixed level of current distortion, MPDPC is capable of outperforming Pulse Width Modulation (PWM) in terms of switching losses.