Gradient-Based Predictive Pulse Pattern Control With Active Neutral Point Potential Balancing for Medium-Voltage Induction Motor Drives

This paper presents a control method for medium-voltage (MV) drive systems consisting of a three-level neutral-point-clamped (NPC) inverter and an induction machine. The proposed approach aims to achieve stator current reference tracking and balancing of the neutral point (NP) potential in one computational stage, without the help of additional control loops. To this end, a model predictive control (MPC) algorithm, designed as a multiple-input multiple-output (MIMO) controller, manipulates optimized pulse patterns (OPPs) in real time. As a result, minimal current harmonic distortions are produced, while the NP potential is kept balanced both during steady-state and transient operating conditions. The effectiveness of the proposed control approach is validated in a real-time system by simulating the MV drive of interest in a hardware-in-the-loop (HIL) setting.