Implementation of High-Precision Quadrature Control for Single-Stage SECS

In this paper, a high precision quadrature control for a single-stage solar energy conversion system (SECS) is presented with power quality improvement capabilities. The SECS uses a voltage source converter (VSC) which performs multifunctions. It harvests maximum energy from the solar photovoltaic (SPV) string and it integrates the extracted energy to the grid. In addition, it utilizes a SPV feed-forward loop to improve the dynamic response and reduces the burden on the proportional-integral controller by regulating dc bus voltage. To control the switching sequences of VSC, a high precision quadrature control is used which extracts the fundamental current from the contaminated load current. The mathematical formulation of quadrature control is corroborated by the experimental results of SECS under different operating conditions.