• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.215-216
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• 2005

Nowadays, mobility as well as basic performances has been the important performance index of hard disk drive, It makes a system unstable to satisfy mobility, huge storage capacity and high transfer rate. Shock and vibration analysis has been important because hard disk drive could be exposed by external shock and vibration. The probability of this situation has been increasing. In this research, each component and the whole system of 2.5in HDD are made to a finite element model. Results of finite element analysis are compared with the results of experimental modal analysis. Shock analysis is executed for 2.5in hard disk drive.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2006.06a
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• pp.77-80
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• 2006

This paper based on spiral vector, three phase induction motor is described a detailed modeling by a phase segment methode. Based on this model, A torque control and the equation of regenerative power for the induction motor drive, based on the field acceleration method(FAM), is presented. The speed control system is designed to be applied voltage source inverters that is easy the current type feedback of power regeneration for motor drive. The ability of shaving power to be measured power regeneration has been investigated in speed acceleration and reduction. And it is change of stator resistance that the voltage commands include error, the ripple of exited voltage and torque occur from the results. The experimental tests verify the performance of the proposed regenerative drive for FAM, proving that good behavior of the drive is achieved in the transient and steady-state operating conditions.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2646-2648
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• 2002

This paper deals with a comparative evaluation of the reliability of control rod drive mechanisms including their driving methods for nuclear power plants. Basically there exist two types of electromagnetic-jack-type drive mechanisms in commercial use that are called as Control Rod Drive Mechanism and Control Element Drive Mechanism. Each type has corresponding drive sequence to make the movements of insertion and withdrawal. A state-space model is derived for each model graphically. Then the evaluation of the reliability is carried out on the programming tool called SHARPE. The evaluation does not give any meaningful numerical values for the reliability but just shows a relative degree to each other in view of reliability.

• Nuclear Engineering and Technology
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• v.31 no.1
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• pp.1-8
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• 1999

In this paper, we propose a new type of power control system for the rod drive coil of the CEDM of the PWR NPP in order to supply more reliable DC power The electrical modelling of the controlled rod drive coil was done by referring related documentations. The design of the proposed system is based on this electric81 model satisfying the existing specification. A high power DC-DC converter scheme is adopted utilizing the SMPS technique in the design of the proposed system. In order to show the effectiveness of the proposed system, an experimental system with the capability of 3.2 K Watt was set up for a rod with four cores and some computer simulations and experimentations were carried out. The result shows a very similar tracking performance with that of the existing system to the driving command. As a result of this, the proposed method can be applied to the power control system for the rod drive coil of the CEDM of the PWR NPP.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.3
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• pp.526-533
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• 1990

The dynamic stability of a single cam drive mechanism is investigated by an analytical approach. The nonlinear differential equation describing the motion of a single cam drive mechanism is linearized with respect to the imput power angle, and results a linear parametric differential equation. The instability region is examined by applying the harmonic balance method to linearized parametric equation having periodicity. Through the dynamic stability analysis of a single cam drive mechanism, it is observed that the parametric resonances exist and the instability regions tend to become wide as increasing the drive speed and follower mass.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.991-997
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• 2003

A flow field around a disc in an optical disc drive is invested using numerical methods. The high-speed rotating disc induces a strong flow field around the disc, which causes the pressure distribution on the surfaces of the disc. The pressure difference between the upper and the lower surfaces causes the deformation of the disc. In the first part of this study, flow fields around a rotating disc and a stationary wall are investigated using a similarity solution method, in order to identify the effect of the distance between the disc and the wall on the pressure distribution on the surfaces of the disc. In the second part, flow field in a slim-type optical disc drive is studied using a commercial code in order to consider the effect of the vortices generated by the local geometry of the drive.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.592-597
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• 2003

To solve a problem of micro drive due to small size and portability, it is necessary to understand and to investigate micro drive widely ,deeply. So, we performed modal analysis of suspension of micro drive, and load/unload experiment for Input current to VCM coil and disk speed. To determine the effect of ramp profile, curve fitting of lateral speed is performed with equation of speed. The results indicate that small load/unload speeds decrease the number of head/disk contacts, and during unloading process, low disk speed increase the number of head/disk contacts.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.3 no.3
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• pp.206-214
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• 1991

Flow field in a hard disk drive has been predicted numerically. Theoretical model was constructed based on a commercially available hard disk drive with 40 Mega byte capacity. Since the gap between disk tip and shroud is not homogeneous in real hard disk drive, three kinds of gap size have been tested as computational model. The discussion has been made on the circumferential velocity, radial velocity, and pressure fields. As a result, the average shear stress on the disk surface was reduced as the gap size decreased. This means that the shroud should be designed compactly to reduce power consumption of the spindle motor.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.83-86
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• 2005

This paper proposed a hydraulic pump system which uses a variable SR drive and constant capacity pump. The base and maximum speed, torque are determined from displacement capacity of the pump and maximum pressure. The drive system is set to have a minimum power consumption having hydraulic preset pressure, which is operated within a maximum capacity and maximum preset pressure. This is achieved by controlling motor speed and power with feedback signal of pressure of the hydraulic pump. A 2.2kw, 12/8-pole SR motor and DSP based digital controller are designed and prototype drive system is manufactured. The proposed variable speed SR drive system is simulated and tested with experimental set-up. The test results show that the system has some good features such as high efficiency and high response characteristics.

• Journal of Power Electronics
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• v.2 no.1
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• pp.19-24
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• 2002

The torque of SRM depends on a phase current and the inductance of the motor. But the inductance is saturated nonlinearly according to the position and current. To drive the motor effectively, the control scheme should take into account the nonlinear characteristics of the magnetic material. This paper proposes an optimal control scheme for high efficiency drive of SRM by adjusting both the turn-on and turn-off angle. The high efficiency drive points are simulated and searched by using GA-Neural Network The switching angles are nonlinearly varied with rotor speed and load.