Model predictive control of neutral-point clamped inverter with harmonic spectrum shaping

This paper proposes a variable sampling frequency model predictive control (VSF-MPC) to achieve fixed-switching frequency operation for a neutral-point clamped (NPC) inverter. The proposed control technique simultaneously considers load current control, balancing of DC-link capacitor voltages, mitigation of common-mode voltage, and elimination of even-order and inter-harmonics in the load current harmonic spectrum, while maintaining fixed-switching frequency operation. The challenges associated with weighting factor design are also addressed. Through the simulation and experimental tests on an NPC inverter, it has been demonstrated that the proposed method preserves high dynamic response nature of MPC, and predefined harmonic spectrum characteristic of classical space vector modulation.