Experimental validation of a Low-Voltage Back-to-Back Converter Control Strategy

The study extensively examined a low-voltage back-to-back converter: a three-phase grid-connected converter and a residential inverter connected to its DC side. The paper comprehensively analyzes their control schemes in the dq axes. A PI controller maintains the DC-bus voltage and balances power flow in a closed-loop system. Additionally, a PI-based closed-loop current control has been utilized to regulate the output current of the inverters. The SRF-PLL is employed for grid voltage synchronization. The DC-bus voltage and the inner current controller are designed using the pole-zero elimination approach and frequency response analysis. The proposed technique aims to achieve equilibrium in the grid currents and point-of-common-coupling voltages while regulating the power fed or absorbed from the grid. So, the system ensures balanced V
dc
voltage, minimizes oscillation in power exchange, and achieves power control. The performance of the suggested method has been validated by simulations in MATLAB/SIMULINK software. Additionally, various laboratory experiment results are presented.