จำนวน Repository ( 26 )

Bidirectional resonant converter using duty cycle voltage control for CCTV solar energy
Bidirectional resonant converter using duty cycle voltage control for CCTV solar energy

This paper proposes the bidirectional resonant converter with duty cycle voltage control using for CCTV with solar energy. The converter designed at 20 KHz for 20 W with 92.85 % of efficiency is operated at zero voltage switch mode for reducing the losses of converter. The modes of operation divide in two modes for operating bidirectional current. The first part is buck mode which has 5 volt at the output voltage and second is boost mode which has 8 volt at the output voltage. The two operation modes of converter will be discussed in this paper.

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การประเมินคุณภาพไฟฟ้าในระบบจำหน่ายที่จ่ายไฟให้พื้นที่นิคมอุตสาหกรรม
การประเมินคุณภาพไฟฟ้าในระบบจำหน่ายที่จ่ายไฟให้พื้นที่นิคมอุตสาหกรรม

This paper presents an assessment of the quality of electricity transmission and distribution system to supply power to the industrial area. The objective is to analyze the power quality that customer in the industrial area need high level. By analyzing the power quality of Provincial Electricity Authority (PEA) in transmission system 115 kV distribution system 22 kV and 400/230 volt in Rojana industrial park from power quality meters. The study concluded that the phenomenon occurs continuously consist of RMS voltage power frequency voltage unbalance short term flicker long term flicker Harmonic meet the standards applied to all. The phenomenon occurs temporary consist of transient voltage dip voltage swell interruption in the conclusion the power quality problems caused by voltage dip most especially with loads which are sensitive to voltage. From the moment the measurement showed that the voltage dip on transmission system 115 kV maximum of 19 times. The voltage dip that occur including three voltage level of 30 times there are events that do not pass SEMI F47 standard 12 times or 40%.

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Wind turbine simulator based on constant Volts/Hertz control   three phase induction motor drives
Wind turbine simulator based on constant Volts/Hertz control three phase induction motor drives

This article presents the application of the constant Volts per Hertz control to control a three phase induction motor has torque and speed characteristics similar to wind turbine. Due to this method is not complicated and does not require the parameters of motor. As a result the accuracy of control is independent of variation of the parameters of motor. Furthermore the equation for compensate the difference between the moment of inertia of wind turbine and motor which is consistent with the mentioned control method is proposed. In order to make the dynamic responses of the wind turbine simulator similar to the wind turbine and to overcome the problems of noise amplification from differentiation that leads to instability of the system. The simulation results in Matlab/Simulink program show that the proposed wind turbine simulator can imitate the wind turbine accurately both in dynamic and steady state conditions

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Design of cmos voltage reference circuit
Design of cmos voltage reference circuit

This paper presents a CMOS voltage reference design which is widely used in electronic circuits both analog and digital circuits. In the conventional a CMOS voltage reference circuit design composed of several MOS transistors and complicated circuits the output voltage cannot be adjusted to any levels. Therefore in this paper proposed the CMOS voltage reference circuit design technique based on a new current combination circuit which it was reduced number of MOS transistors and the proposed circuit is able to operate without complex startup circuit. The performance of the proposed circuit is confirmed through PSPICE simulation results the circuit can be operated with supply voltage varies from 2V to 4V the output voltage reference is about 231 2mV at wide temperature range of -80 to 120 it has very low temperature coefficient of about 37.65 ppm/ and a total power dissipation of 7.37 W

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Grounding system analysis for reduce voltage sag in distribution system
Grounding system analysis for reduce voltage sag in distribution system

The fault in a power distribution system disturbs the power dispatch under normal conditions therefore decreases the quality of the electric power. The single line to ground fault is an asymmetric fault that may have a high percentage chance to happen. The kind of fault changes power and voltage dramatically. The size of the phase voltage decreases which affect the economic damage of the system. This paper presents an analysis of grounding systems to reduce voltage drop in a power distribution system by using the technical analysis system in case of one phase to ground fault. The objective is to minimize voltage drop for users using the simulation with single line to ground fault in distribution system voltage level at 22 kV PEA’s test system. The simulation utilizes the EMTDC-PSCAD program. The results show that the grounding method can reduce the voltage drop and reduce the damage of the economic system

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