Voltage source back-to-back power converters are widely used in grid-tied applications. This paper presents a Quasi-Centralized Direct Model Predictive Control (QC-DMPC) scheme for back-to-back converter control without a DC-link outer-loop controller. Furthermore, the QC-DMPC is experimentally compared with a conventional Proportional-Integration (PI) DC-link controller based DMPC (PI-DMPC) scheme. For the QC-DMPC scheme, the DC-link voltage is directly controlled by a grid side predictive controller using a dynamic reference generation concept and load side power estimation. For the PIDMPC scheme, the DC-link voltage is controlled by an external PI controller. Both schemes are implemented on a Field Programmable Gate Array (FPGA) based platform. Effectiveness of the proposed QC-DMPC is verified by both simulation and experimental data. Moreover, FPGA implementation issues (resource usage and timing information), DC-link control performance and robustness to parameter variation of the two DMPC schemes are compared in detail. The results emphasize that the QC-DMPC may outperform the PI-DMPC scheme in normal operation but with a slightly higher usage of FPGA resources. However, PIDMPC scheme is more robust when parameter variations are considered.     «

Voltage source back-to-back power converters are widely used in grid-tied applications. This paper presents a Quasi-Centralized Direct Model Predictive Control (QC-DMPC) scheme for back-to-back converter control without a DC-link outer-loop controller. Furthermore, the QC-DMPC is experimentally compared with a conventional Proportional-Integration (PI) DC-link controller based DMPC (PI-DMPC) scheme. For the QC-DMPC scheme, the DC-link voltage is directly controlled by a grid side predictive cont...     »