Predictive Current Control with Selection Vector Table Scheme for 3L-NPC Inverter

Abstract

The predictive current control (PCC) strategy has been widely applied to three-level neutral-point-clamped (3L-NPC) inverters to regulate the load current and balance the capacitor voltage. However, evaluating all 27 switching states in each sampling period imposes a significant computational burden. At the same time, current quality is sensitive to selection of weighting factors when multiple control objectives are simultaneously considered. To overcome these limitations, this paper proposes two methods, namely predictive current control with vector selection Table I (PCCT1) and vector selection Table II (PCCT2), in which only a subset of pre-selected switching states is employed for prediction and optimisation, thereby eliminating the need for weighting factor tuning in the cost function. As a result, computational complexity is significantly reduced and system stability is enhanced. The proposed PCCT methods demonstrate superior performance compared to conventional PCC under various operating conditions, ensuring accurate current tracking and consistent capacitor voltage balancing.