• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.124-128
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• 2002

This Paper propose a novel sensorless drive system for the trapezoidal brushless DC motor in Bow speed region. The inverter DC input voltage is controlled by step-down converter for low speed operation. A indirect rotor position sensing technique based on a detailed analysis of the terminal voltage characterisrics is proposed in this paper. A sensorless drive system is implemented using a TMS320F240 for the main process and IPM(Intelligent Power Module) for the inverter.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1791-1801
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• 2016

This paper considers a carrier based signal injection method for use in the three shunt sensing inverter (TSSI) for sensorless motor control. It also analyzes the loss according to the injection axis of the voltage signal. To remove both the phase current and rotor position sensors, a sensorless method and a phase current reconstruction method can be simultaneously considered. However, an interaction between the two methods can be incurred when both methods inject voltage signals simultaneously. In this paper, a signal injection based sensorless method with the 120° OFF Discontinuous PWM (DPWM) is implemented in a TSSI to avoid this interaction problem. Since one leg does not have a switching event for one sampling period in the 120° OFF DPWM, the switching loss is altered according to the injection axis. The switching loss in the d-axis injection case can be up to 32% larger than that in the q-axis injection case. Other losses according to the injection axis are also analyzed.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.2
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• pp.63-68
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• 1999

This pper describes a digital sensorless drive of permanent magnet brushless DC motors. In order to detect in real time the rotor positions of which Emf becomes zero, terminal voltages are sampled during PWM duty cycle. This method generates detection error in indirect sensed position, which is the harmonic component of PWM frequency. In this paper, the drive adopted Butterworth low pass filter for rejection of the sensing error and for accurate estimation of commutation time. Analytical design process of the digital filter is proposed and the experimental results show that the performance of the proposed sensorless drive is superior to that of the sensorless drives without filterint.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.15-17
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• 2002

자기 베어링을 구동하는 코일은 회전축의 위치 정보를 가지고 있다 따라서 코일의 인덕턴스를 알 수 있으면 위치 센서를 쓰지 않고도 회전축의 위치를 알아낼 수 있다. 본 논문에서는 코일에 고주파 신호를 주입하여 인덕턴스를 알아내고, 이를 통해 회전축의 위치를 추정하는 방법을 제안하고. 실험을 통해 이를 검증한다.

• Journal of Ship and Ocean Technology
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• v.8 no.1
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• pp.10-30
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• 2004

High-fidelity RANS simulations are presented for a ducted marine propulsor, including verification ＆ validation (V＆V) using available experimental fluid dynamics (EFD) data. CFDSHIP-IOWA is used with $\textsc{k}-\omega$ turbulence model and extensions for relative rotating coordinate system and Chimera overset grids. The mesh interpolation code PEGASUS is used for the exchange of the flow information between the overset grids. Intervals V＆V for thrust, torque, and profile averaged radial velocity just downstream of rotor tip are reasonable in comparison with previous results. Flow pattern displays interaction and merging of tip-leakage and trailing edge vortices. In interaction region, multiple peaks and vorticity are smaller, whereas in merging region, better agreement with EFD. Tip-leakage vortex core position, size, circulation, and cavitation patterns for $\sigma=5$ also show a good agreement with EFD, although vortex core size is larger and circulation in interaction region is smaller.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.71-74
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• 2012

Generally, tone noise is generated at the rotary wing and helicopter. BVI(Blade-Vortex Interaction) noise is one of the helicopter's tone noise. The BVI noise is governed by tip-vortex characteristics such as vortex size, strength and trajectory. To avoid BVI, many methods have been developed and proposed. In this paper, rotating blade with active tab was numerically investigated to reduce BVI noise. For flow and noise simulation, the lifting surface approach and the acoustic analogy were used. Using numerical methods, the noise directivity and maximum noise position were predicted.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.119-122
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• 2001

본 논문은 브러시리스 DC 모터 드라이브에서 위치센서를 제거하기 위해, 측정한 상전압 및 상전류로부터 쇄교자속과 쇄교자속의 미분간에 의해 속도를 구하고 이를 이용하여 위치를 추정하는 새로운 센서리스 구동방식을 제안한다 이러한 센서리스 구동알고리즘은 ${\alpha}-{\beta}$ 기준축을 이용하여 구현하였다. 구동시스템을 구현하기 위한 제어기는 고속연산이 가능하면서도 저가인 고정소수점 연산 DSP인 TMS320F241을 채택하였다. 제안된 알고리즘은 그 원리가 간단하고 우수한 제어특성을 나타냄으로써 실제적인 브러시리스 DC 전동기의 센서리스 구동을 위한 훌륭한 대안이 될 수 있을 것이다.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.135-137
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• 2001

In slotless synchronous motor for precise position and speed control, eccentricity of rotor mass cause torque ripple, speed ripple and harmonics of back emf. This paper deals with magnetic field and characteristic analysis for ring type slotless synchronous motor by using analytical method. And then, speed and back emf harmonics are analysed.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.138-140
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• 1994

The torque production of SRM is dependent on the variation of inductance which is related to rotor position angle. So the realization of high efficiency SRM is achieved by design of optimal inductance profile appropriate for magnetic capacity of motor. This can be obtained by optimal design of winding number of stator. This paper suggests the design standard of winding number of stator for high efficiency. And this paper shows the experimental results of driving performance of SRM.

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.568-570
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• 1997

In this paper, we develope the micro-stepping driver circuit for 5-phase step motor having pentagon type winding and improve the position control performance of the rotor, $0.45^{\circ}$, $0.028125^{\circ}$, $0.0140625^{\circ}$ per step.