Autonomous operation of wind-battery hybrid power system with maximum power extraction capability

The hybrid operation of a remote area power system consisting of a Doubly Fed Induction Generator (DFIG) based wind turbine, a battery storage unit and a dummy load is investigated in this paper. The battery storage unit operates as a source or load, depending on the wind power output and loading conditions of the system. The battery storage is connected to the AC side of the wind energy system through a three phase inverter to supply both active and reactive power. A dummy load is also incorporated into the AC side of the system. The design criteria of the controllers for each component (ie. DFIG, battery storage system and dummy load) and an approach for control coordination of the entire system are presented in this paper. The suitability of the proposed control coordination strategy and individual system controllers are tested in relation to the system voltage, frequency and DC link stability of the DFIG under variable wind and changing load conditions. The maximum power extraction capability from wind is also achieved throughout the operation

Tidal energy in Australia – Assessing resource and feasibility to Australia’s future energy mix

This paper presents an overview and progress of a recently commenced three year project funded by the Australian Renewable Energy National Agency led by the Australian Maritime College, (University of Tasmania), in partnership with CSIRO and University of Queensland. The project has a strong industry support (OpenHydro Ltd, Atlantis Resources Limited, MAKO Tidal Turbines Ltd, Spiral Energy Corporation Ltd and BioPower Systems Ltd) and aims at assessing the technical and economic feasibility of tidal energy in Australia, based on the best understanding of resource achievable. The project consists of three interlinked components to support the emerging tidal energy sector. Component 1 will deliver a National Australian high-resolution tidal resource assessment; in Component 2, case studies at two promising locations for energy extraction will be carried out; lastly, Component 3 will deliver technological and economic feasibility assessment for tidal energy integration to Australia’s electricity infrastructure. The outcomes of this project will provide considerable benefit to the emerging tidal energy industry, the strategic-level decision makers of the Australian energy sector, and the management of Australian marine resources by helping them to understand the resource, risks and opportunities available

Optimisation of component sizes for a hybrid remote area power supply system

In this paper, an optimisation model for determination of the optimal sizes of various system components, including wind, diesel and energy storage, has been developed to obtain a reliable and cost-effective wind-diesel hybrid remote area power supply (RAPS) system. A linear programming based cost minimisation algorithm has been formulated for determination of optimal sizes of various components in a RAPS system with consideration of continually varying wind and system load. The system constraints, including power balance for both under-generation and over-generation scenarios, have been considered in the optimisation formulation. Optimisation model to minimize the total cost of the system based on hourly net present cost for both a one-day period and one-week period have been developed with allowance for unserved load during low wind conditions

Enhanced reactive power support of a PMSG based wind turbine for a remote area power system

Due to the intermittent nature of wind, a wind turbine generator alone cannot supply all the active and reactive power required by the load at all times in a standalone environment. As a close relationship exists between reactive power and voltage magnitude, reactive power support is the mean used to maintain the desired voltage profile, both during normal and contingency conditions. In this paper, a synchronous condenser is integrated into the AC bus of a wind turbine generator based hybrid Remote Area Power Supply (RAPS) system where a Permanent Magnet Synchronous Generator (PMSG) is used to satisfy the active power load demand of the system. In this regard, the reactive power provision from the wind turbine generator is maintained to be zero. A battery storage is used to stabilise the DC link of the converter/inverter arrangement

Rotor position and speed estimation of a variable structure direct-torque-controlled IPM synchronous motor drive at very low speeds including standstill

The performance of a speed sensorless variable structure direct-torque-controlled interior permanent magnet synchronous motor drive at very low speeds including standstill is investigated in this paper. The rotor position and speed are estimated using a high-frequency (HF) signal injection algorithm at low speeds and a sliding observer at medium to high speeds. The changeover between these two algorithms is performed using a weighting function which smoothly hands over the estimated rotor position information for stator flux and torque estimation purposes. Experiments were performed to test the effectiveness of the proposed HF signal injection algorithm, and results show that the sensorless drive is capable of accurately estimating the position and speed at very low speeds including standstill. The implementation of the changeover algorithm to switch between the two observers at low and high speeds has enabled sensorless operation of the drive from zero to base speed

Power generation in isolated and regional communities: application of a doubly-fed induction generator based wind turbine

The application of a doubly fed induction generator (DFIG) as a suitable generating scheme in a remote or isolated communities is presented in this paper. Remote area power supply (RAPS) system, a dummy load and its controller with energy storage system (ESS) are identified as the key components. The dummy load is used to absorb the power associated with over generation. The battery storage system is used as a storage buffer which could absorb or release the power into the RAPS system when required. It is also used as a secondary control for the DC link voltage of the back-back converter of the DFIG. The hybrid operation of the DFIG, dummy load, ESS and main load is discussed in relation to the system voltage,frequency and DC link stability. The entire hybrid model has been developed using the SimPowerSystem tool box in MATLAB

Progressio

Due to the uncertainties associated with wind profiles, the load side voltage and frequency control of a wind dominated Remote Area Power Supply (RAPS) system is a challenging task. The performance of such a wind dominated hybrid RAPS system consisting of a diesel generator, fuel cell system, dump load and mains load is investigated in this paper. Integrating a fuel cell into the RAPS system enables the diesel usage to be kept at its minium level while avoiding operation of the diesel generator at low load factor. The diesel generator is used to provide the reactive power requirement of the system throughout the operation and to provide active power whenever necessary. The excess power that arises during over generation scenarios such as high wind and low load conditions are handled through the dump load. To achieve acceptable voltage and frequency regulation, individual controllers have been designed and developed for each system component. In addition, a strategy for control coordination has been established among all the system modules. The entire system was modelled using SimpowerSystem toolbox in MATLAB and the suitability of the system is investigated in relation to its voltage and frequency regulation capability under changing wind and variable load conditions

Unesco heute : Zeitschrift der Deutschen Unesco-Kommission

A novel Remote Area Power Supply (RAPS) system consisting of a Doubly Fed Induction Generator (DFIG) wind turbine generator, synchronous diesel generator system, battery storage system and a dump load is considered in this paper. A control coordination strategy is formulated with a view to regulate the system voltage and frequency within acceptable limits while extracting the maximum power available from the wind. The battery storage unit is used to provide a smooth state transition from Wind-Only (WO) to Wind-Diesel (WD) mode while enabling the DFIG to operate in its maximum power point tracking mode of operation. The dump load is used to absorb the excess energy which cannot be utilised through the battery storage system. The entire RAPS system has been modelled using SimPowerSystem toolbox in MATLAB

Hydrogen energy storage for a permanent magnet wind turbine generator based autonomous hybrid power system

The Performance of a novel hybrid Remote Area Power Supply (RAPS) system consisting of a Permanent Magnet Synchronous Generator (PMSG), fuel cell system, electrolyser and synchronous condenser is investigated in this paper. The fuel cell system is used to provide power during under-generation scenarios whereas the electrolyser absorbs excess power during over-generation conditions. A synchronous condenser is incorporated into the RAPS system to provide better reactive power and inertial support. Individual controllers for each system module have been developed and implemented. A control coordination methodology is established with a view to regulate the active and reactive power balance of the RAPS system while extracting maximum power from wind for optimal operation of the RAPS system. The entire system was modelled using SimpowerSystem block set in MATLAB and through simulation studies, it has been demonstrated that the proposed RAPS system is able to regulate the voltage and frequency within acceptable limits throughout its operation even during wind speed and load changes

Revue internationale des services de santé des forces armées : organe du Comité International de Médecine et de Pharmacie Militaires ; trimestrielle

A novel hybrid Remote Area Power Supply (RAPS) system consisting of a Doubly Fed Induction Generator (DFIG) based wind turbine and a battery Energy Storage System (ESS) is investigated in this paper. The proposed RAPS system also consists of a dummy load and its controller. The battery energy storage system is used as a buffer which is connected to the DC link of the DFIG. The dummy load which is connected to the AC side of the system is used to absorb the energy associated with over generation, a situation which cannot be handled through the battery system. Control coordination of the dummy load and battery storage system helps maintain the system instantaneous power balance thus ensuring the regulation of the system frequency. The suitability of the proposed RAPS system is assessed in terms of the bandwidth of voltage regulation capability. Small signal model analysis although simpler to perform, is undertaken with a view to compare some of the corresponding results with those obtained using detailed models. Detailed modular simulation of the system is discussed in relation to the system voltage, frequency, DC link stability of the doubly fed induction generator and power sharing among different system components. The model of the entire system has been developed using SimPowerSystem toolbox in MATLAB