Stand-alone Power Generation System Research Articles

Maximum power throughput in the multiphase brushless DC generator

An advanced control technique for maximum power throughput of the multiphase brushless DC (BLDC) generator is presented. In a generator of given rating the weight and size of the system affect the fuel consumption of the generation system directly, especially in vehicle applications. Therefore maximum power density is one of the most important issues in a stand-alone power generation system. A BLDC generator itself has high power density from the machine point of view and additional increases by special control means can be expected. Conventional rectification methods cannot achieve the maximum power possible because of nonoptimal current waveforms. An optimal control scheme to maximise power density and minimise machine size and weight in a multiphase, nonsinusoidal power supply system is proposed, incorporated into a control system, and verified by simulation and experimental work.

Real Time Simulation Scheme for Stand-Alone Wind Power Generation Systems

The cost effective researches and developments on the WPGS under various conditions considering sort of wind turbines, generators, and load capacities have been expecting. For that purpose, a novel simulation method based on the real-time digital simulator (RTDS) is proposed in this work for the real time simulation of stand-alone Wind Power Generation Systems (WPGS) under the real weather conditions. A standalone WPGS, especially, is simulated by Simulation method for WPGS using Real Weather conditions (SWRW). A model that can be used to represent any type of wind turbines in power system simulations is presented. The characteristic equation of a wind turbine is implemented in the RTDS, and the real data of weather conditions are interfaced to the RTDS for the purpose of real time simulation of stand-alone WPGS. The outcomes of the simulation demonstrate the effectiveness of the proposed simulation scheme. The results show that the cost effective verifying for the efficiency and stability of the WPGS is possible.

Fuel Cell Operation with Oxygen Enrichment

AbstractExperimental results on the performance of a Ballard 5 kW proton exchange membrane fuel cell stack for different oxygen contents in the oxidant are presented. A description of the experimental setup is given. Polarization, power, and efficiency curves as a function of the current density, for different oxygen concentrations are presented. This detailed characterization of the fuel cell stack behavior is required in order to evaluate the effects of oxygen enrichment on the net power output of the stack. This investigation is done in the framework of a project on stand‐alone power generation systems using renewable energy sources, and based on hydrogen production and storage. An electrolyzer, powered by the excess electrical energy from renewable energy sources, produces hydrogen. The stored hydrogen could then be used to feed an energy conversion device, such as a fuel cell stack, which acts as a secondary power source in periods of high demand. Therefore, a second objective is to evaluate the possibility of using the oxygen produced by the electrolyzer for the enrichment. Other oxygen enrichment techniques such as membrane gas separation and pressure swing adsorption are also discussed. Net available power and system efficiency are used as comparison factors.

Dynamics and stability of a wind stand-alone power system

A simulation and digital computer model of a wind stand-alone power generation system, including wind turbine generator pitch control and a Superconducting Magnetic Energy Storage (SMES) unit, is developed for dynamic and stability evaluation. The effect of introducing the SMES unit for improvement of stability and system dynamic response is studied. The wind turbine generator pitch control gain is optimized by actual integration of squared errors in the response. The frequency deviation due to load perturbation is reduced using the SMES unit. Analysis of system stability has been explored using an eigenvalue sensitivity technique. The response of the power system with optimal gain setting to random load changes due to the random nature of the wind has then been studied.

Optimal sizing of stand-alone photovoltaic solar power systems

We examine simple yet accurate analytic procedures for designing optimal stand-alone photovoltaic power generation systems. Solar electricity systems can represent a cost-effective alternative to high cost, conventional, diesel-fired generators, particularly in developing countries where most of the population lives in rural and isolated areas. However, the lack of simple but accurate analytic design tools currently results in either (a) significant, wasteful oversizing or (b) extremely high design costs for one-of-a-kind projects. The analytic solutions discussed here can bring the price of stand-alone photovoltaic systems to economic viabilty at today's hardware and fuel prices, and can also enable local designers in developing countries to design these systems economically and on their own. The analytic models are based on the theory of stochastic processes, and stem from analyses originally developed for analogous water reservoir, queueing and insurance risk problems.