Model Predictive Control of a Modified Nested Neutral-Point Clamped Inverter

In this article, a modified nested neutral-point clamped (MNNPC) inverter with a five-level (5L) operation is proposed. The 5L-MNNPC inverter has a smaller number of flying capacitors (FCs) and has redundancy switching states, which allows better controllability of the FCs voltage compared with the existing 5L-NNPC topologies. In the proposed MNNPC inverter, each FC voltage should be maintained at one-fourth of the net dc-bus voltage to produce a 5L output voltage waveform. The proposed topology’s structure and its operation are discussed and analyzed thoroughly. Also, a model predictive control (MPC) approach is introduced to control the proposed 5L-MNNPC inverter’s ac currents and FC voltages. The sampled-data models are developed to implement the MPC method for the proposed inverter. On the basis of the multi-objective cost function, the optimal switching state will be determined from the assessment of all available switching states. The MATLAB simulation studies are presented to demonstrate the proposed 5L-MNNPC inverter’s functionality and its performance.