PROJECT TITLE :

Finite States Model Predictive Control for Fault Tolerant Operation of Three-Phase Bidirectional AC/DC Converter Under Unbalanced Grid Voltages - 2017

ABSTRACT:

The bidirectional ac/dc converter is widely used to appreciate the ability conversion between ac and dc microgrid, but the faults of switch devices and unbalanced grid voltages may lead to the decline of power quality and have an effect on normal operation of the converter. The four-switch 3-section (FSTP) fault-tolerant structure is reconstructed from a six-switch 3-part structure with switch device fault. In order to scale back harmonic currents and output power fluctuations underneath unbalanced grid voltages, finite states model predictive direct power management (MPDPC) with power compensation method is proposed for FSTP structure and predictive power model of the bidirectional FSTP ac/dc converter is established. The ability compensation values are expressed by grid voltages and their quadrature signals that lagging ninety electrical degrees within the aß stationary coordinate system. Compared with the traditional methodology, section-locked loop, pulse width modulation, and complex positive-/negative-sequence extraction of grid voltage are not required. Ripples of active power or reactive power under unbalanced grid voltages are eliminated. The proposed fault-tolerant MPDPC with power compensation method ensures the continual and reliable operation of the bidirectional ac/dc converter with high power quality. Simulation and experimental results are presented to validate the proposed control strategy beneath symmetrical unbalanced grid voltages with switch device faults.