Passivity-Based Partial Sequential Model Predictive Control of T-Type Grid-Connected Converters With Dynamic Damping Injection

Abstract

LCL-filter interfaced three-level T-type converters (LCL-3LT <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> C) have been widely used in low-voltage applications due to their elevated power quality. However, there exist several problems. To begin with, the performance of the finite-control-set model predictive control (FCS-MPC) controlled 3LT2C relies on an accurate system model and measurement. Consequently, output performances will be influenced when model parameter mismatches, grid impedance variation, and the dead-time of power devices occur. In addition, the robustness of the FCS-MPC controller may also encounter challenges under disturbances and noise. Further, LCL-filter has the resonance problems in the grid currents, which may endanger the system stability. To solve these problems, a passivity-based (PB) partial sequential MPC (PSMPC) with dynamic-damping (DD) injection (DDPB-PSMPC method), which outperforms FCS-MPC and ensures the asymptotic stability, is proposed. First, the passive output voltage based on the Euler-Lagrange (EL) model is obtained using dynamic damping injection. Second, by embedding passive output voltage into MPC, a passivity-based PSMPC robust controller is designed to enhance its anti-disturbance abilities and achieve resonance suppression. Finally, to avoid the time-consuming of weighting factor selection, a PSMPC that allocates non-conflicting objectives in the same layer is introduced. Experimental results on 10-kW prototype demonstrates its excellent performance over existing techniques.