Control of Solar PV System for Power Quality Improvement in AC Network and Islanded Operation

Abstract

The harmonics currents drawn by the nonlinear loads distort the point of common coupling (PCC) voltages. It affects the performance of the solar PV system (SPVS) and other sensitive loads, connected at the same PCC. Moreover, it increases the line losses in the AC network. Hence, this paper presents an adaptive filter-based control algorithm for the SPVS to improve the power quality (PQ) in the AC network as par the IEEE standard 519 and to reduce its line losses. The presented adaptive filter algorithm effectively filters out the harmonics from the sensed voltages and currents and reduces the DC offset caused by the sensor circuitry. Moreover, in this paper, an adaptive DC-link control approach is presented to regulate the DC link voltage of the SPVS, which ensures that the modulation index remains less than 1. Hence, the harmonics currents injected by the SPVS at the PCC, are reduced. Moreover, the SPVS separates itself from the AC network to uphold the IEEE std. 1547, if any abnormality occurs in the AC network voltages. In this condition, it feeds power to the loads by changing its mode of operation to the islanded mode. Hence, the energy generated by the SPVS is effectively utilized and its payback period reduces. A Simulation study is carried out in various dynamics conditions to uphold the performance of the presented control algorithm.