FPGA Predictvie Control for Single-Phase Active NPC Grid Inverters with Multi-Sampling Technique

Abstract

This paper presents an FPGA predictive control scheme for the active T-type neutral-point-clamped (AT-NPC) inverter in applications to grid inverters. Predictive control technique benefits from its fast response but also suffers with its high sensitivity to measurement noises and parameter uncertainties. To overcome the sensitivity problem of predictive controller, a multi-sampling strategy is developed to get its instantaneous average value and at the same to minimize possible sampling errors during the sampling process. The proposed control scheme can combine advantages of digital control with flexibility and accuracy and analog control with fast response. The designed predictive controller has been realized using a mixed-signal FPGA SmartFusion r A2F500 from Microsemi. Experimental verification is carried out with a 3kW single-phase AT-NPC grid inverter. Experimental results show that the proposed control scheme can achieve both fast dynamic responses and high quality current regulation with THD close to its theoretical limits.