This research paper has aimed to provide an insight into developing a control strategy for a standalone wind energy conversion System (SWECS) intended to power a DC load. The System mainly consists of the wind turbine (WT), generator, power electronics devices, battery bank, and its charging control circuit along with pitch angle control of wind turbine. Charging of battery is attained through tip-speed ratio (TSR) MPPT logic. DC-DC converter acts as a charge controller which charges the battery in a controlled way. Pitch angle control mechanism generates appropriate pitch angle command to dampen the rotational speed of the wind turbine. It limits the turbine output power, generator speed and rectifier output voltage during high wind speed ensuring electrical and mechanical safety of the wind turbine. The three-phase self-excited induction generator (SEIG) coupled with a wind turbine is used to produce electrical power. It is connected to load via the AC-DC-DC converter to obtain regulated voltage at the load side. The efficacy of control logic developed for proposed wind energy conversion System is tested in MATLAB/Simulink platform varying wind and load profile.

This paper presents nonlinear frequency control characteristic for a dispatchable source to reduce fuel consumption in a standalone AC power System. Power management used in grid is local. The proposed frequency characteristics that are employed for the sources are designed based on grid model. To have robust frequency control characteristics, uncertainty in grid model that consists of load model and line impedance parameters uncertainties are considered. In other word, the parameters of the proposed frequency characteristics are computed with existing uncertainty in grid model. The frequency characteristics are designed as piecewise linear characteristics between two load levels in the grid. By solving an off-line optimization problem, the parameters of proposed frequency characteristics are obtained. Simulation results shows performance of the proposed frequency characteristics that caused reduction in fuel consumption and robustness respect to grid model uncertainty.

In this paper, a framework for multi-objective optimization of a hybrid photovoltaic/diesel generator (PV/DG) System has been presented. This study follows the design of the PV/DG System at the lowest cost, lowest emission and highest reliability. The total net present cost (TNPC), CO2 emissions and the loss of power supply probability (LPSP) are selected as the problem objectives. This System has been designed in three scenarios: 1-without considering uncertainty and operating reserve, 2-with considering uncertainties of the System and 3-with considering uncertainties of the System and using DG as operating reserve. In order to effectively solve this problem, multi-objective version of crow search algorithm (MO-CSA) has been developed and the results are compared with the results obtained by well-known non-dominated sorting genetic algorithm II (NSGA-II). The coding of the problem has been done in MATLAB environment and the Pareto fronts have been compared. Simulation results indicate that combination of DG and PV is a promising alternative for supplying the electrical demand of Stand-Alone areas. Moreover, the results obtained by MO-CSA outperform the results obtained by NSGA-II.

Introduction: Metastatic involvement of the spine may present with pathologic fractures, deformity, neurologic deficit due to vertebral canal compromise, and pain. Pain is usually managed with non-steroidal anti-inflammatory agents, corticosteroid injections, calcitonin, etc. Since the introduction of percutaneous vertebroplasty in 1984, it has proven as an effective armamentarium in the management of painful metastatic spine lesions. Herein, we present a case of breast cancer with osteolytic C2 metastasis, forwhom trans-oral vertebroplasty without posterior fusion resulted in long-standing pain control and maintenance of normal motions and stability. Case Presentation: A41-year-oldwoman, aknowncase of breast cancer with severe neck pain for three months, was admitted due to an osteolytic lesion in C2. The pain was incapacitating and resistant to conservative measures. Standalone transoral vertebroplasty resulted in pain control and a three-year follow-up showed durable control of pain. After positioning the patient and insertion of Dingman mouth gag, the oropharynx was prepped and injected with epinephrine/lidocaine solution. Under biplanar fluoroscopic guidance, a needle was introduced into the C2 body through the oropharynx. The lytic lesion was filled with about 2 cc of PMMA cement. The VAS score decreased from 10 prior to operation to 5 immediately after recovery from general anesthesia and improved to 2 after six months. At a 36-month follow-up visit, the VAS score was 0, normal cervical motions were preserved, and lateral neutral and dynamic cervical X-rays disclosed stability. Conclusions: Standalone transoral vertebroplasty can be safely practiced as an effective treatment for painful osteolytic metastases of C2 with normal dynamics.

The switched reluctance motor is a singly excited, doubly salient machine which can be used in the generation mode by selecting the proper firing angles of the phases. Due to its robustness, it has the potential and the ability to become one of the generators to be used in the harsh environment. This paper briefly discusses the energy conversion by a switched reluctance generator (SRG) when two switches per phase converter circuit and discrete position sensors are employed. It is well known fact that, as the generator’s speed increases by a prime mover and the shape of the current waveform changes in such a way that limits the production of generating voltage. At high speeds, it is possible for the phase current never reaches the desired value to produce enough back-EMF for sufficient voltage generation, therefore, the output power falls off. In order to remedy this problem, the phase turn on angle is advanced in a way that the phase commutation begins sooner. Since one of the advantages of this type of generator is its variable speed then, the amount of advancing for the turn on angle should be accomplished automatically to obtain the desired output voltage according to the speed of the generator, meaning, as the generator speed increases so should the turn on angle and vice versa. In this respect, this paper introduces an electronic circuit in conjunction with time reshaping of the command pulses obtained from position sensors and the drive converter to achieve this task for a desired output voltage when a SRG feeding a resistive load. To evaluate the generator performance, two types of analysis, namely numerical technique and experimental studies have been utilized on a 6 by 4, 30 V, SRG. In the numerical analysis, due to the highly non-linear nature of the motor, a three dimensional finite element analysis is employed to calculate some of motor parameters and then using these parameter, current shape and magnitude are computed, whereas in the experimental study, a proto-type generator and its circuitries have been built and tested using two-switch per phase converter. A linear analysis of the current waveform for the generator under different advancements of the turn on angle has been performed numerically and experimentally and the results are presented.

This paper deals with standalone small power generation employing three self-excited induction generators under varying speeds feeding an isolated load. The proposed System utilizes three-level cascaded H-bridge inverter for the three generators. The control scheme has the capability of regulating the output voltage for balanced operation of a three-phase isolated load under variable speed. The proposed control can be implemented using DSPACE 1104, and the experimental results are presented to demonstrate the effectiveness of the proposed controller for an isolated generating System.

Introduction: Evaluation of hospital information System (HIS) is a complex endeavor, in which all human, technical and organizational aspects should be considered. This study aimed to develop indicators for HIS evaluation.Methods: Present qualitative study was carried out through a cross-sectional method in 2012 in Kerman province, using Delphi technique. Given the objectives of this study, three independent phases were performed including literature review, providing draft indicators for HIS evaluation and reaching consensus. Required data were obtained through interviews and designed forms. Twenty-three experts composed the study population in interview and reaching consensus phases. Validity and reliability were confirmed through content validity and test-retest method, respectively. Data were analyzed using descriptive statistics.Results: Final set of indicators for HIS evaluation consisted of ninety-one indicators under 8 main topics, i.e. technical quality, software quality, architecture and interface quality, vendor quality, after-sale services quality, workflow support quality, support department, outcome quality and HIS cost.Conclusion: Given the complexity of information System evaluation, all human, technical and organizational aspects have to be taken into account in any evaluation. Proposed indicators provide the possibility of comprehensive evaluation of HIS.