A MMC Based Three-Phase Wind Energy Inverter (WEI) With Flexible AC Transmission System

A Power quality problem is an occurrence of nonstandard voltage, current or frequency that results in a failure or a misoperation of end user equipments. Utility distribution networks, sensitive industrial loads and critical commercial operations suffer from various types of outages and service interruptions which can cost significant financial losses. With the increase in load demand, the Renewable Energy Sources (RES) are increasingly connected in the distribution systems which utilizes power electronic Converters/Inverters. This paper presents a single-stage, three-phase grid connected solar photovoltaic (SPV) system. The proposed system is dual purpose, as it not only feeds extracted solar energy into the grid but it also helps in improving power quality in the distribution system. The presented system serves the purpose of maximum power point tracking (MPPT), feeding SPV energy to the grid, harmonics mitigation of loads connected at point of common coupling (PCC) and balancing the grid currents. The SPV system uses a three-phase voltage source converter (VSC) for performing all these functions. An improved linear sinusoidal tracer (ILST)-based control algorithm is proposed for control of VSC. In the proposed system, a variable dc link voltage is used for MPPT. An instantaneous compensation technique is used incorporating changes in PV power for fast dynamic response. The SPV system is first simulated in MATLAB along with Simulink and simpower system toolboxes.