Nonadaptive CDSC Based Control of a Single Phase PV System Tied to Distribution Grid

Abstract

The nonadaptive cascaded delayed signal cancellation (CDSC) based control algorithm is proposed for a double stage photovoltaic (PV) system tied to the distribution grid. The proposed control algorithm uses five αβDSC operators in cascade with delay factors of 8, 16, 32, 64, and 128 to filter out double frequency oscillation, to ensure a 90° phase difference between it’s α- axis and β-axis outputs, and mitigates all odd harmonics under both nominal and off-nominal frequencies to ensure accurate fundamental component of load current tracking. This control has good DC offset rejection. This control technique extracts active component of load current, to generate sinusoidal reference grid current. The PV system to DSTATCOM (Distribution Static Compensator) mode, and DSTATCOM to PV system operation, besides injecting active power to the grid, is demonstrated through test results. The total harmonic distortion (THD) in grid current is attained within the compliance of distribution grid code as imposed by the IEEE-929 and 519 PQ (Power Quality) standards.