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The paper has as first objective the overview of the active distribution networks for the future, their viability with existing equipment and components. The presented applications are intended for industrial-type networks with local power generation in view of their efficient integration into an intelligent distribution network. The main scientific goal of the paper is to test the stability issues...
Based on previous research experience proved by simulated and experimental results a comparative discussion about advantages and disadvantages of using Vector Control or Direct Torque Control for PM-SM drives is presented.
This paper analyzes a new architecture of the AC/DC type power supply for data centers. The source cumulates the following functions: three-phase current rectification, transformation of voltage parameters and DC voltage stabilization. The source ensures the reactive power compensation and does not distort the currents in the power three-phase network. The transfer of power from the alternating current...
Equipped with outdated installations from the nineteen-fifties and nineteen-sixties, Chisinau CHP-1, operates with an electrical efficiency below 20%. However its decommissioning encounters several problems, related to the shortage of power generation in the republic, and to the difficulty of ensuring the thermal load during the summer time. A reasonable solution would be to disassemble the medium...
Solution to the problem of maintaining the efficiency and stability of the developing industry is subject to quick and sudden changes in the globalizing business environment has recently been of priority in the scientific research. In the dynamic background of the institutional and innovative transformation in Russia activities of industrial enterprises are subject to risks of resource deterioration,...
In this work, the characteristics of a Si-solar cell (PV) model is studied. The proposed modelis a four layer system with an ultra-thin film of Fe-InGaAsPlaid above Silicon (Si) substrate and covered by AlON layer that is exposed to air directly. The efficiency is measured by the reflectance power (R) and transmittance power (T). R and T are derived by using the transfer matrix method for both TE...
Dua\ output hybrid converter supplying DC and AC loads simultaneously are gaining interest due to their compact size. This is due to single stage conversion that results in cost saving and offers decoupled control of both AC and DC output. Though hybrid converter derived from boost was reported, they were unable to supply lower DC output. The hybrid converter proposed in this paper is able to supply...
This paper studies the influence of three volute geometries of a single-stage centrifugal compressor, using the same vaned diffuser and impeller, the only differences are given by the volute geometry: cross section area and volute tongue. The objective of this research is to determine which of parameters has a major impact on the compressor and how much are the operating range and overall performance...
Given the great potential of biomass in Romania, companies that use endothermic processes have the possibility switching from fossil fuel to a cheaper and more available alternative. Furthermore, through cogeneration they can reduce costs, by producing electricity for own consumption. While wooden biomass has an inferior low heat caloric value, organic fluids can be used to harvest the heat, where...
Three GaN-based buck switching power stage architectures are implemented using discrete GaN High Electron Mobility (HEMTs) devices and compared with respect to efficiency, switching speed (2 to 10MHz), and power conversion ratio for medium-power applications. The three presented power stage architectures are: a single-stage buck, a multi-phase buck with 2 phases, and a stacked interleaved configuration...
This paper presents aspects of the technical evolution in micro-networks efficiency with respect to the power quality and system availability. Different potential approaches for market using are shown. The environmental and economic effects of the micro-networks depends of their implementing phases, like design, commissioning and testing. It can be a lot different than the normal main grid, depending...
Energy balance of electromechanical converter of a multi-module structure with a common hollow massive rotor has been considered. Design capacity for the motor module is chosen based on the sum of thermal and mechanical output. For the brake module operating in the mode of opposition circuit only thermal mechanical output can be chosen. These capacities are determined by preliminary thermal and hydrodynamic...
In this article, is described a design of concept an hybrid solar generating module based on high-efficiency silicon solar cells with mirror concentrator of solar radiation and solar cells cooling system for build up a high-performance solar energy station. The necessity of this work based on experimentally established influence of the working temperature and solar radiation power on the efficiency...
The main goal of the research is development and practical implementation of new methods for processing large amount of data in building automation, which will allow acquiring, storing and interpreting data about the urban environment as well as modelling its processes using high performance computation and next generation smart sensor infrastructure. This will ensure automatic or semi-automatic high...
High frequency is an effective method to improve transmission efficiency of inductively coupled power transfer (ICPT) system. However, it is hard for the high capacity semiconductor device to meet the high frequency need. In this paper, a novel multiple-frequency inductively power transfer system is proposed. By adopting a novel multiple-frequency topology of inverter, the transfer frequency of the...
For LCL type grid-tied three-phase inverters, a model predictive controller is proposed. Through the controller, system performance indexes, i.e., current tracking, inductor loss, switching loss can be combined and then optimized. Since the controller is a constrained nonlinear problem, an on-line algorithm is presented which is based on branching and bounding method. Finally, through Matlab simulation...
In this paper, loss equivalent models of power electronic elements are built to discuss the power loss and efficiency of power electronic systems in real-time simulation. Based on element's dynamic characteristic and loss theory, loss equivalent models which include power switch, inductor and capacitor are established. A real-time simulation circuit of boost converter is tested and compared with the...
An optimization method is proposed for the geometric parameters of an convergent nozzle ejector in the anode gas recirculation system in PEM fuel cell in this paper. The mathematical model of ejector is established by employing the hydrodynamics, thermodynamic principles and chemical constraints. An optimization method is applied based on hybrid fish swarm algorithm to optimize the geometry parameters...
Energy efficiency in communications of all types is of growing importance to society. All efficiency loss is due to power dissipation in the electronic circuitry used to implement the communication standard. Selection of the modulation adopted by a standards working group has a dominant role in how much of the energy efficiency available from electronic technologies and circuit structures can be made...
Magnetic coupled resonant wireless power transmission technology has broad prospects for development; this paper takes this as the object of study. Based on the traditional wireless power transmission system, a new three-winding system is proposed. Firstly, the transmission efficiency expressions of two systems and the factors influencing the efficiency are derived. Secondly, based on the chaotic...
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