High-frequency isolated hybrid distribution transformer based on model predictive control

With the increasing proportion of new sources/load in distribution substations, the problems of poor power quality such as high/low voltage, harmonic amplification, and three-phase imbalance at distribution terminal and insufficient capacity of power frequency transformers to support the increasing load demand are becoming more prominent. In order to maximize the development of distribution substations, this paper proposes a high-frequency isolated hybrid distribution transformer, which has functions of comprehensive power quality control and AC/DC hybrid distribution, and can meet the high-quality power supply and friendly connection requirements of new sources/load for distribution terminal users. Firstly, the topology structure of the high-frequency isolated hybrid distribution transformer is introduced and the mathematical model is derived. Then, based on the characteristics of the topology structure, continuous-set model predictive control (CCS-MPC) strategy and delayed MPC control strategy are designed to calculate the optimal duty cycle and achieve output with fixed switching frequency and switching sequence, reducing the optimization computation. Finally, a 10kV/0.4kV full power level high-frequency isolated hybrid distribution transformer system is built using MATLAB/Simulink simulation software to verify the effectiveness of the proposed topology structure in comprehensive power quality control.