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This paper proposes a novel method of suppressing inrush currents of squirrel-cage induction machines using matrix converters in wind power generation systems. In the proposed method, the output side of the matrix converter behaves as a resistor for the source current and the input side of the matrix converter compensates reactive power of the squirrel-cage induction machine. Digital computer simulation...
In this paper, an experimental application focused on energy quality observation is developed and power factor correction for the electrical power systems is simulated. The required parameters are obtained from the system by electronic cards and then transferred to the computer. As the controller a (DAQ) Data acquisition card is used and also a user-friendly interface is prepared for computing and...
This paper presents an analysis of characteristics of choke-input-type diode rectifier circuit on three-phase rectangular-voltage-fed distribution system. The validity of the analysis has been confirmed by experiments using the 2.4 kW prototype.
The purpose of this paper is to present a novel digital control boundary current mode ac-dc converter. The ac-dc converter is widely used as power factor correction. The ac-dc converter that operates in a boundary current mode has the some advantages. It has capability to achieve low current distortion. The unity power factor is theoretically obtained by the boundary current mode control. In the proposed...
This paper presents a simple control strategy for a variable speed wind energy conversion system with a permanent magnet synchronous generator (PMSG). PMSG is connected to the grid through a switch mode rectifier and a voltage source inverter. The grid should be supplied by certain levels of powers for certain times from wind energy system according to a certain schedule. Batteries bank is connected...
In this paper, a novel single-stage parallel topology power circuit is presented. It can be used in LED street lights for widely power range, from 80 W to 300 W. This topology contains two control methods. One is the constant-voltage feedback, and the other is the constant-current feedback. With this design, this power circuit can provide LED a stable constant current. Besides good stability in linear...
The paper presents the results of studying the specific problems that occurred during the exploitation of two 42 MVA bulb generators. The work focuses particularly on two groups of problems which were more pronounced on only one of the two hydropower units, and these are increased vibrations of the hydropower unit and electromechanical oscillations in the stationary and transition states, which significantly...
As the penetration of electric vehicles increases the number of chargers for these vehicles are also increasing and therefore, will increase the electric energy grid consumption. To integrate these needs with the green energy, the use of electric chargers with a solar photovoltaic installation makes perfect sense. However, these charges can also be used for the support of the reactive power compensation...
This paper presents a real time operation of tap changing transformers and converters interfaced with distributed generators (DGs) in unbalanced three-phase distribution systems. The unbalanced three-phase power flow equations are solved using Newton Raphson method, and the three phase elements models are considered. Since the renewable energies are attracting worldwide attention, the DGs considered...
This research is aimed to present technical loss analysis in Vientiane capital. Electricité du Laos (EDL), the state enterprise company that is responsible for transmission and distribution of electricity in Lao People's Democratic Republic (Lao PDR). The purposes of this research studies are technical line losses and reduce power losses of distribution in Vientiane capital by using CYMDIST program...
We propose a novel active islanding prevention method for large penetration of photovoltaic (PV) systems by detecting the harmonic impedance change, and have developed the simulation models for PV inverters which have new active methods by using PSCAD/EMTDC. We also study the performance of islanding detection functions in non detection zone (NDZ) by simulation analysis and clarify the effectiveness...
Since the Great East Japan Earthquake, many people had been worried about power shortages in Japan. There has been more focus to installation of Renewable Energy Sources (RES). In Japan, PV system introduction is promoted by national policy of the government in 2012. However, the large amount of distributed generator causes voltage deviation beyond the statutory range in distribution system. Furthermore,...
Battery energy storage systems (BESS) become increasingly more important due to the impact of volatile energy sources on the power supply and present a good solution for buffering the power imbalances in the electric grid. Particularly with regard to a future scenario with electrical energy, means have to be taken to ensure a stable and reliable power supply. Redundant BESS allow normal operation,...
An example of circuit design is presented on new concept 2-kVA ac voltage/current regulator with resistive load or inductive load. Any load power-factor is acceptable on inductive load. For output control and input PFC (power-factor correction), new devices “Variable Capacitance Devices” can be utilized. Small dc-dc converters are excellent high-speed driver for these devices.
In this paper, application of Fuzzy-PI control for the voltage source converter based permanent magnet synchronous wind generator is proposed in order to improve Fault Ride Through (FRT) capability of wind farm including fixed speed induction generators. The membership of fuzzy logic controller is designed based on the bode diagram analysis to achieve a good stability performance of the controller...
In recent years, amount of renewable energy facilities using wind turbine generator and photovoltaic power system have been increased due to natural environment and resource depletion. Moreover, all electrification apartment houses or residences and electric vehicles have been increased. However, due to the fluctuating power from renewable energy sources and loads, fluctuations of grid frequency and...
In tandem with the penetration of PHV as well as EV, contact-less power supply system in parking towers have become important subjects. In parking towers, EV and PHV are charged on the traveling pallets, supply power is to be transmitted from the building to travelling pallets. In this paper, high-frequency link AC-AC converter for contact-less power supply system in parking tower is newly proposed...
Photovoltaic (PV) generation technologies, often deemed a viable solution for reducing greenhouse gases and decreasing electricity demand, have become increasingly prevalent in their deployment. Particular progress in their implementation has been evidenced in residential areas characterized by rooftop-mounted PV arrays. Aside from the known advantages provided by residential PV generation, one noteworthy...
This paper studies the impact of large-scale PV generation, up to 50% penetration level, on distribution system voltage regulation and voltage stability. The system voltage profiles are computed using power-flow calculations with load variation of a 24-hour time scale. The voltage stability is examined at different times of the day using a developed continuation power-flow method with demand as continuation...
This paper proposes an optimum PWM method which reduces switching losses of a three-level NPC inverter most effectively by the two-phase modulation method. It selects the optimum one which minimizes a new switching (SW) loss estimation based on reduction effects in switching times considering phase currents among multiple reduction patterns. The proposed method was experimentally verified to select...
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