CCS-MPC with Long Predictive Horizon for Grid-Connected Current Source Converter

Abstract

Model predictive control (MPC) with a long predictive horizon can offer significant benefits, especially for a power converter with high-order filters, such as virtual-impedance based active damping loop that can be eliminated. In this article, the continuous-control-set model predictive control (CCS-MPC) with a long prediction horizon is investigated for the grid-connected current-source converter (CSC). The cost function in multi-variable form is designed, which ensures power command tracking and LC filter resonance suppression simultaneously. The optimized control law is generated by a modulator to obtain a constant switching frequency. The single MPC loop can replace conventional multiloop control with reduced complexity and simplified tuning process. Simulation and experimental results show that the long horizon MPC for CSC can achieve satisfactory performance as well as improved robustness for the variation of system parameters.