Model Predictive Current Control of a 4-Level Negev Rectifier

In this paper, the design and implementation of a model predictive current controller for a nested (T-Type) 4-level Negev rectifier is presented. This power converter is a modification of the Vienna rectifier that allows the generation of three partial DC link voltages, while maintaining a unity power factor at the utility grid side. This topology is intended to be a grid interface for supplying partial DC voltages to multilevel inverters, eliminating the need of voltage balancing control in the inverter’s side. The mathematical model of this converter is also presented and based on it, the model predictive controller is developed. To evaluate/compare the controller’s performance, a time division multiplexed on-off controller is also implemented in MATLAB/Simulink. Simulation results show the performance of both control strategies considering different operating conditions, in which, the proposed controller produces better total harmonic distortion levels in grid currents and voltage ripple in partial DC voltages.