S Ambica sony

Bio: S Ambica sony is an academic researcher from VIT University. The author has contributed to research in topics: Total harmonic distortion & Clamping. The author has an hindex of 1, co-authored 1 publications receiving 1 citations.

Transformerless full bridge neutral point clamped inverter topology for renewable energy sources

Abstract: Transformerless inverters are becoming popular, especially in the field of renewable energy systems because of their compactness in size and higher efficiency. However these topologies are suffering from leakage currents and they can be reduced by clamping the neutral point during freewheeling modes. Two types of basic switching cells are introduced to build the proposed topology. They are positive neutral point clamping cell and negative neutral point clamping cell. Using these two cells proposed topology is clearly explained. In this paper unipolar sinusoidal pulse width modulation (UPSPWM) which is already existing and modified unipolar sinusoidal pulse width modulation (MUPSPWM) which is proposed to these topologies for getting an improved result. These two types used for creating switching pulse pattern for all topologies and then obtained results are compared in respect of THD. Existing topologies like OH5 and full bridge dc bypass (FB-DCBP) are also simulated with both PWM techniques and their results are compared to proposed topology in respect of total harmonic distortion (T.H.D) and number of switches. Results showing in this paper are validated by simulating with MATLAB.

A performance comparison of transformer-less grid tied PV system using diode clamped and neutral point shorted inverters

Abstract: Grid tied photovoltaic (PV) system is an operation mode of PV system working together with utility power supply to provide power to the power load. Conventionally, transformer is used together with the power inverter. The power transformer works as galvanic insolation amongst PV system and power grid. It works also to raise the voltage of power inverter. However, use of transformer will add system complexity, price, weight and size of the entire system. Transformer-less system is an alternative to make the system simpler and more practical in use. The paper discusses performance of transformer-less grid tied PV systems using diode clamped and neutral point shorted inverters. Effects of transformer elimination to the feat of the grid tied PV system especially harmonics content and leakage current of PV system were examined and analyzed. The performance was also compared with the traditional system using H-bridge inverter. The leakage currents did not flow in the system applying diode clamped inverter, and neutral point shorted inverter. In case of harmonics content, the diode clamped inverter injected less harmonics components than the neutral point shorted inverter. The neutral point shorted provides a simpler inverter circuit in the transformerless systems. Normal 0 false false false MS X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman",serif;}