Harmonic Minimization in a Modified Cascaded Multilevel Inverter for Islanded Microgrid using two Switching Techniques

Abstract

IntrouctionEver increasing in the energy demand, fossil fuels exhausting nature and growing prices, environmental problems caused like CO2 emissions from conventional power plants have made more research to be carried out on renewable energy based distributed power generation systems. Various renewable energy sources are available among them the wind and photovoltaic are very promising and popular around the globe. Microgrid can be framed with intelligent control using both renewable sources wind and solar with energy storage. These type of microgrids at a remote location can help to depend less on the power grids. Microgrid fed from renewable energy resources is discussed in [1][2][3]. These papers are not including the performance of system parameters such as power quality, efficiency of the system, under various operating conditions. The place is very much important for the availability of the renewable resources for continuous generation of electricity supply. It is very much required that the system must be used at optimum point to harness maximum energy and in turn reduce the cost price. Multilevel inverters are attracting the industries due to their ability to produce smooth sinusoidal output voltage waveforms with lower switching frequency. It has spread in the research areas for studying higher voltages and power applications [4] due to the lower switching losses, higher effciecncy and EMI inference. Multilevel inverters are available for both high switching and low switching configurations. With high switching means lower efficiency

Power Quality Assessment of Voltage Positive Feedback Based Islanding Detection Algorithm

“…The sliding mode controller schematic diagram for GCPVS with string inverter is illustrated in Fig. 2 (2) where K pf controls the disturbance size; and ΔV PCC is the PCC voltage deviation. When the grid is lost, the active power mismatch leads to a V PCC variation and the applied feedback drifts ref away from its MPP setting.…”

“…With respect to the considerable penetration of GCPVSs in distribution networks, the inverter's current control loop, which is responsible for DC to AC power conversion, is one of the major sources of harmonics. While this power quality degradation is negligible concerning the new switching patterns [2]- [4], active islanding detection methods (IDMs) are recently known as a new source of current harmonics [5].…”