• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2004.11a
• /
• pp.220-224
• /
• 2004

The present paper deals with the numerical study to analyze the self-starting performance of impulse turbine in a reciprocating air flow generated by sinusoidal motion of wave inside oscillating water column. Result was compared to that of Wells turbine, well-known wave energy conversion device, and showed that the impulse turbine has a superior self-starting ability. More detailed parametric study was performed to demonstrate the effects of moment of inertia of rotor, loading torque, tip clearance and angle of guide vane.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.9
• /
• pp.1119-1124
• /
• 2018

So far BESS(Battery Energy storage system) has been widely applied to power systems rapidly. Usually it has been used to regulate the renewable energy output and to adjust the power system frequency. In 2013, EPRI has reported a study of utilizing BESS to replace two black start generators of American Electric Power(AEP) that will be demolished. If the BESS can be used as a self-starting generator, it is possible to shorten the long-distance primary transmission line and shorten the restoration time because BESS is capable of the high-speed start and there is no restriction on the installation position. This paper presents a possibility of using BESS as a self-starting generator by using PSCAD/EMTDC in Korean power systems. Herein, the process to estimated the required capacity of BESS is also presented.

• Korean Journal of Optics and Photonics
• /
• v.8 no.5
• /
• pp.357-361
• /
• 1997

We report the operation of a self-starting phase conjugate laser(PCL) oscillator which compensates intracavity phase distortion. The self-starting PCL in the population inverted Nd:YAG gain media produced an output energy of 200 mJ in a 20 ns single-longitudinal-mode pulse at 10Hz. And it showed well-defined Gaussian spatial profile.

• Proceedings of the KIEE Conference
• /
• 1998.07f
• /
• pp.1987-1989
• /
• 1998

A single phase induction motor is predominant in fractional horsepower rating and is widely used in home and industrial equipment. For example, these motors provide the motive power to washing machines, fans, refrigerators, etc. In this paper has presented the design and implementation of a microcontroller software - based self - starting SPIM. The control algorithm used in the experimentation employed simple control strategies which enabled a single chip programmable microcontroller to execute both the self - starting and self - detecting control of SPIM with relatively simplified hardware.

• Proceedings of the KIPE Conference
• /
• 2007.07a
• /
• pp.226-228
• /
• 2007

SRM drive systems are designed to meet operating standards such as low cost, constant torque independent of rotor position, a desired operating speed range, high efficiency, and high performance. In applications using small motors, low cost and high performance with self-starting capabilities are highly desired. This paper discusses a novel two phase SRM (TPSRM) that has high performance characteristics with self-starting capability, low manufacturing cost with a two phase inverter and simple magnetic structure, and high efficiency. The principle of operation, analysis, and simulation for design are presented. The machine design is verified using finite element analysis (FEA) software. Analysis and simulation results are given to validate the TPSRM design.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.6
• /
• pp.2268-2275
• /
• 2018

This paper presents a high-efficiency low-power permanent magnet (PM) generator for the power supply of the generator exciter. In the conventional generator system, the power for the exciter is fed by the generator output power or an emergency battery for the starting. The proposed low-power PM generator can generate the proper power and voltage to excite the exciter field winding. According to the starting of the generator, the designed PM generator can supply the constant voltage to the Automatic Voltage Regulator (AVR), then it can be used to control of exciter field current for the generator. Because of the designed PM generator which is placed inside the conventional generator system, the emergency battery and Potential Transducer(PT) for AVR can be removed. Thus, the total efficiency can be improved. The proposed generator system is tested in the practical system. And the efficiency characteristic is analyzed.

• Journal of Energy Engineering
• /
• v.29 no.1
• /
• pp.34-43
• /
• 2020

A study has been done for self-starting torque of vertical axis wind turbine blade. It is especially concentrated to evaluate the torque coefficient before starting rotation. Two different aerofoils(AMI903 and AMI904) are proposed to benchmark the possible best blade(supercritical airfoil) for self-starting performance. Torque coefficients in the tangential direction of rotation are given with respect to the angle of attack in terms of drag coefficient and lift coefficient. Torque coefficient shows that the effect of Reynolds number is minimal. The thicker blade(AMI904) between two different proposed airfoils has bigger torque coefficient, which is attributed to lower lift coefficient and higher drag coefficient.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.5 no.4
• /
• pp.13-20
• /
• 2006

The inherent problem of a Darrieus wind turbine is its inability to self-start. Usually, a motor is used to provide angular acceleration until lift forces are produced in the airfoil blades or up until the turbine can already sustain its speed on its own. This paper describes a method of improving the self-starting of an H-type Darrieus vertical axis wind turbine (VAWT) by incorporating a helical Savonius turbine thus utilizing a drag-lift combination. The effect of each turbine in the combination relative to each other is investigated by testing a prototype windmill consisting of three NACA 0015 airfoil blades combined with a Savonius rotor with a helix angle of 180 degrees and whose swept area equals 30% of the entire turbine.

• 유체기계공업학회:학술대회논문집
• /
• 2003.12a
• /
• pp.3-12
• /
• 2003

This paper reviews the present state of the art on the self-rectifying air turbines, which could be used for wave energy conversion. The overall performances of the turbines under irregular wave conditions, which typically occur in the sea, have been evaluated numerically and compared from the viewpoints of the starting and running characteristics. The types of turbine included in the paper are as follows: (a) Wells turbine with guide vanes (WTGV); (b) turbine with self-pitch-controlled blades (TSCB); (c) biplane Wells turbine with guide vanes (BWGV); (d) impulse turbine with self-pitch-controlled guide vanes (ISGV) and (e) impulse turbine with fixed guide vanes (IFGV). As a result, under irregular wave conditions it is found that the running and starting characteristics of the impulse type turbines could be superior to those of the Wells turbine. Moreover, the authors have explained the mechanism of hysteretic behavior of the Wells turbine and the necessity of links for improvement of the performance of ISGV.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.813-814
• /
• 2006

The squirrel case induction motor has widely used in the driving of the blowers but it is low efficiency and hard to control. So, the damper is used for the control of a flow and it cause to low the driving efficiency. Our laboratory has proposed the single-phase SRM(switched reluctance motor) for driving blowers. It has salient pole structure and can be reduced a number of semiconductors than three-phase SRM. But it can not be starting by itself and has heavier torque ripple than three-phase SRM. For self-starting the single-phase SRM is required the starting device which place the rotor at the rising inductance slope. On this paper, the electromagnet starting device is designed to generate the starting torque and to fix the rotating direction of the single-phase SRM which is fabricaed to use a blower.