Averaged Modeling and SRF-Based Closed-Loop Control of Single-Phase ANPC Inverter

This article presents a dynamic averaged model of active neutral point clamped inverter (ANPCI). The proposed model helps in significant reduction of computational resources required for system-level studies in various applications which employ ANPCI as main power conversion stage. The average model derived in this article can consider the effect of various nonidealities in ANPCI, and also its capacitor voltage-balancing issues. The model is also modular in nature, i.e., it can be extended for an N-level ANPCI. PSCAD/EMTDC simulations and experiments are performed for steady-state and transient conditions to show that the averaged model developed in this article accurately predicts the steady-state and dynamic waveforms of ANPCI in both open-loop and closed-loop operations, even for large simulation time-steps. For the closed-loop operation, synchronous reference frame
$dq$
-based controller is developed and implemented in a digital signal processor. In addition, the strength of the model is demonstrated by comparing the simulation waveforms and computational times required for simulating an ANPCI-based solar PV system using switching circuit model and the proposed averaged model.