A UVT based control for single-stage grid interfaced SPV system with improved power quality

This paper presents a single stage grid connected SPV (Solar Photo-Voltaic) energy conversion system with a simple unit vector based control which also ensures improved power quality at PCC (Point of common coupling). The SPV energy conversion system compensates for linear and nonlinear loads which are connected at PCC, with the objectives of MPPT (Maximum Power Point Tracking), balancing of grid currents, harmonics mitigation and correction in power factor to unity. The UVT (Unit Vector Transform) is used to estimate fundamental active power component of load currents which along with PV power feed-forward loop and a DC-link PI (Proportional-Integral) voltage controller is used to estimate the peak value of reference grid currents. The feed-forward loop improves the dynamic response of the system with reduced settling time. The proposed grid connected SECS (Solar Energy Conversion System) is implemented using a DSP (Digital Signal Processor) and its performance is verified simulated and test results under various operating conditions.