Showing papers by "C.V. Nayar published in 2007"

A grid current-controlling shunt active power filter

Abstract: In this paper, the implementation of a three-phase shunt active power filter is presented. The filter is essentially three independent single-phase current-controlled voltage source inverters (CC-VSI) with a common DC bus. The CC- VSI is operated to directly control the AC grid current to be sinusoidal and in phase with the grid voltage. The APF consists of a current control loop, which uses polarized ramptime current control and a voltage control loop, which employs a simple Proportional Integral control. The experimental results indicate that the active filter is able to handle predominantly the harmonics, as well as the unbalance and reactive power, so that the grid currents are sinusoidal, in phase with the grid voltages and symmetrical.

Analysis and design of a solar charge controller using cuk converter

Abstract: This paper presents a scheme for transferring power from the photovoltaic (PV) modules to a battery using a solar charge controller based on a Cuk dc/dc converter. The converter is configured in parallel power transfer mode (PPT) to achieve higher efficiency. PWM control with maximum power point tracking algorithm is used to extract maximum power from the PV modules. Mathematical modelling and field test results using multi crystalline photovoltaic modules have been carried out to verify the effectiveness of the device.

Modelling, simulation and testing of grid connected small scale wind systems

Abstract: This paper will show the theory, simulation and application of maximum power point tracking for small scale wind turbines. The theoretical section of this paper will cover modelling of the wind turbine, the and the power electronic converters (the full-bridge DC/DC converter and the grid connected current controlled voltage source inverter (CCVSI)). It is shown that by controlling the duty ratio of the DC/DC converter, the wind turbine generator is operated at the maximum power point. This is achieved without measuring the wind speed using a look up table where the power output vs the shaft speed is recorded. In order to keep the output current waveform sinusoidal at varying wind speeds, the DC link voltage of the CCVSI is kept constant. This system meets the utility requirements such as galvanic isolation, anti-islanding protection and protection of the wind turbine at high wind speeds.

A Low Voltage Electronic Ballast Designed For Hybrid Wind-Solar Power Systems

Abstract: This paper describes the development of an illumination system for open and/or isolated areas like gardens, sidewalks, outdoor lighting for residences and rural areas, demonstration plants on Universities, et cetera. The proposed system is based on a 70 W electronic ballast (EB) for high- pressure sodium (HPS) lamps designed to operate from a low voltage automotive lead-acid battery charged by a hybrid wind- solar power system. A new design criteria for a push-pull EB based on the rated current RMS of the lamp is presented. The paper also includes technical issues faced in building the prototype such as transformer losses generated by skin effect, transformer winding isolation and the effect of high MOSFET drain source current.

Development of sustainable power and water supply for remote areas and disaster response and reconstruction in Indonesia

Abstract: This paper presents a finalist project proposal in the Mondialogo Engineering Award 2007 that was constructed through international cooperation between two student groups from Curtin University of Technology, Australia and Gadjah Mada University, Indonesia. The project proposes a development of sustainable power and water supply, by mean of mini-grid hybrid power system with reverse osmosis desalination plant as a deferrable load, for remote areas and disaster response and reconstruction in Indonesia. As a result of recent disasters that have hit Indonesia, many people have lost their access to a reliable power and water supply. Additionally, there are many remote areas and islands that still have no appropriate electricity supply due to geographical conditions that hinder the development of an electricity grid connection because of economic reasons. This paper describes concept of system design process, intercultural dialogue between two student groups from different countries, preliminary site visits on the disaster locations in Yogyakarta, Indonesia, and previous experimental results on 5 kVA mini-grid hybrid power conditioner system, a reverse osmosis desalination plant rated at 5.5 kWh/day, and the upgrading of PV arrays for solar water pumping system (SPWS) rated at 375 W, all are performed at Curtin University of Technology. Through this project, students from Australia and Indonesia collaborated to participate in attaining The United Nations' Millennium Development Goals, especially on eradicating extreme poverty and hunger, ensuring environmental sustainability, and developing a global partnership for development.