POWER QUALITY IMPROVEMENT WITH REDUCED NO OF COMPONENTS FOR STAND ALONE APPLICATIONS
Abstract : Voltage regulation is a main key factor for stable power system. Recent years the electronics equipment growth is rapidly increase. These electronics devices are voltage sensitive devices.
To maintain the grid system voltage equal or near to nominal level, the DVR plays major roll.
The 31 level inverter is proposed in this study to reduce number of switches and maintain constant voltage profile with low current distortion.
The objective of the existing system is to study the system behavior, which allows the renewable energy sources for mitigating voltage disturbances.
This exertion explains the built-in photovoltaic based dynamic voltage restorer (DVR) for alleviation of voltage hang down and engorge mitigation.
The cascaded H-bridge multilevel inverter is used for exchange of real and reactive power to the sensitive load from PV system.
The need of multilevel converter is to give a high output power from medium voltage source. Sources like batteries, super capacitors, solar panel are medium voltage sources.
In cascaded MLI structure, dc sources can be added or subtracted which can increase the number of output levels.
But it needed separate H-bridge according to the increase in output voltage levels. So the number of switching devices required is more.
The switching losses are more, efficiency is reduced, and expense and complexity is increased.
In this paper we propose a high efficiency grid-tied photovoltaic system using a hybrid multilevel inverter.
POD modulation technique is proposed.
The proposed MLI can achieve high efficiency and low harmonics and it can reduce the voltage stress on the power switches and also reduces the no of switches.
In addition to reducing voltage dip and engorge, DVR can also ensure of ephemeral in voltage, line voltage harmonics mitigation and fault current margins.
The main concept of this inverter is to use diodes and provides the multiple voltage levels through the different phases to the capacitor banks which are in series. A diode transfers a limited amount of voltage, thereby reducing the stress on other electrical devices.
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