Decoupled Vector Control of Grid Side Converter with Less Number of Sensors under imbalanced Grid Conditions

In this paper, decoupled double synchronous reference frame (DDSRF) theory is implemented by the help of one dc voltage, two ac voltage and two ac current sensors. These sensors are sufficient for the control of grid side converter (GSC) during balanced as well as imbalanced grid conditions in the three phase three wire system. Since, estimation of unknown voltage and current could be assumed correct as there is no path for the flowing of zero sequence current, while two line to line connected voltage sensors have the information of voltage imbalance during imbalanced grid conditions. Therefore, third phase voltage and current could be estimated by making the sum of two sensed quantities and one unknown variable equals to zero. In this paper, it is verified experimentally for the decoupled vector control of GSC, where, the positive and negative sequence voltages are decoupled through DDSRF while currents are decoupled through enhanced DDSRF methods in the respective dq-axes. It is implemented experimentally using TI-2407A DSP controller.