• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.439-442
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• 2000

An adaptive nonlinear control of a brushless direct drive motor(BLDDM) is proposed. Comparing to the traditional PMSM the direct drive motor has smaller number of per pole and per phase slots to provide higher torque in low speed. This generic construction generates flux harmonics and finally results in unwanted torque harmonics. To control the speed a feedback linearization method is applied by choosing the $i_{ds}$ and $\omega_{m}$ as the output variables. The control of the flux harmonics is provided by using a flux observer with MRAC technique. As shown in the simula-tion results the proposed nonlinear speed controller has a good speed response in the steady state and robust to the flux variation

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.10
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• pp.555-561
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• 1999

This paper proposes a new compensation algorithm for stator resistance that is crucial for improving the direct vector control performance of an induction motor. This algorithm is based on the flux estimator that is derived from the stator voltage equation. Since a flux estimator is dependent on the stator resistance, a flux error originates from the variation of the stator resistance. This parameter mismatch in the estimator thereafter affects the flux and torque response. Accordingly, a new compensator has been designed to offset this degradation in the responses. The proposed compensator is very simple to implement and does not require any modifications to the motor model or any special interruptions of the controller. The value of the stator resistance is attained in real time through measuring the terminal voltage and current. The effectiveness of the proposed scheme has been confirmed through both simulation and experimentation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.65-68
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• 2001

In the vector control methods of induction motor, the stator current is divided into the flux and torque component current. By controlling these components respectively, the methods control independently flux and torque as in the DC motor and improve the control effects. To apply the vector control methods, the position of the rotor current is identified. The indirect vector control use the parameters of the machine to identify the position of rotor flux. But due to the temperature rise during machine operation, the variation of rotor resistance degrades the vector control. To solve the problem, the q-axis is aligned to reference frame without phase difference by comparing the real flux component with the reference flux component. Then to compensate the slip, PI controller is used. The proposed method keeps a constant slip by compensating the gain of direct slip frequency when the rotor resistance of induction motor varies. To prove the validations of the proposed algorithm in the paper, computer simulations is executed.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.236-248
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• 2017

A direct stator flux vector control scheme in discrete-time domain is proposed in this paper for the interior permanent magnet synchronous motor (IPMSM) drive to remove the proportional-integral (PI) controller from the direct torque control (DTC) scheme applied to IPMSM and to obtain faster dynamic response and lower torque ripple output. The output of speed outer loop is used as the desired torque angle instead of the desired torque in the proposed scheme. The desired stator flux vector in dq coordinate is calculated with a given amplitude. The state-space equations in discrete-time for IPMSM are established, the actual stator flux vector is estimated in deadbeat manner by a full-order state observer, and then the closed-loop control is achieved by the pole placement. The stator flux error vector is utilized to calculate the reference stator voltage vector. Extracting the angle position and amplitude from the estimated stator flux vector and estimating the output torque are eliminated for the direct feedback control of the stator flux vector. The proposed scheme is comparatively investigated with a PI-SVM DTC scheme by experiment results. Experimental results show the feasibility and advantages of the proposed control scheme.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.2
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• pp.91-102
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• 1999

The paper describes a robust adaptive control algorithm for induction motor drive without speed sensor at low speed range. The control algorithm use only current sensors in a space vector pulse width modulation within loop control with rotor speed estimation and voltage source inverter. On-line rotor speed estimation is based on utilizing parallel model reference adaptive control system. MRAC of the modified flux model for flux and rotor speed estimator uses dual-adaptation mechanism, ${\omega}_r$ and ${\omega}_e$ scheme. The estimated flux components in the model can be compensated from the effects of offset errors on pure integrals. It can be compensated to the parameter variations and torque fluctuation with speed estimation in less then 10 rad/sec. In a simulation, the proposed induction motor control algorithm without speed sensor at very low speed range are shown to operate very well in spite of variable rotor time constant and fluctuating load without change the controller parameters. The suggested control strategy and estimation method have been validated by simulation study, and it proposed the designed system for the implementation using TI320C31 DSP/ASIC controller.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.2
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• pp.126-131
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• 2014

This paper discusses stability of new simplified sensorless vector control systems of induction motors (IM). The simplified sensorless systems estimate the flux angle by using the output voltage of d-axis PI current controller to achieve the q-axis flux zero. Two simplified sensorless systems are studied. The difference of two systems is the presence or absence of a q-axis PI current controller. The systems stability is compared by deriving linear state equations and showing root loci and unstable regions. Furthermore, transient responses and experiment results make clear the stability of the proposed system.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.476-478
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• 1996

This paper is on speed control of induction motor using space vector PWM. Indirect vector control which controls independantly flux and torque current component in order to drive induction motor, is applied for driving motor. Voltage sourced inverter with space vector PWM is used to generate the practically perfect sinusoidal flux density in induction motor. The appropriateness of speed control is proven by appling IP(Integral-proportional) controller which is known to have a good speed response and still to have less overshoot than the now used PI(Proportional-Integral) controller.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.179-181
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• 2004

This paper is proposed an adaptive fuzzy-neural network(A-FNN) controller based on the vector controlled induction motor drive system. The hybrid combination of fuzzy control and neural network will produce a powerful representation flexibility and numerical processing capability. Also, this paper is proposed speed estimation of induction motor using A closed-loop state observer. The rotor position is calculated through the stator flux position and an estimated flux value of rotation reference frame. A closed-loop state observer is implemented to compute the speed feedback signal. The results of analysis prove that the proposed control system has strong robustness to rotor parameter variation, and has good steady-state accuracy and transitory response.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.752_753
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• 2009

This paper deals with controller design and dynamic simulation of hybrid magnetic bearing. The flux density at air-gap is obtained from system modeling which considers permanent magnet and electro magnet. The vertical force is derived yb that flux density using maxwell's stress tensor.

• Journal of Welding and Joining
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• v.13 no.4
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• pp.24-29
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• 1995

전자제품의 고기능화에 따라 Controller의 중요성은 점점 증대되고 있다. 따라서 Controller(이하 PCB라 칭함)의 제조 공정에서 납땜 관련 Board 재료, Flux, Flux 탄화 연기 등은 식물의 고사 현상등 지구환경을 위협하고 있다. 특히, 자동차 매연이나 도장 또는 PCB 납땜시 SOX, NOX, 탄화수소계등이 휘발하게 되며 아황산 가스 나 질소 산화물이 대기중에서 물과 반응하여 황산 또는 질산으로 변하여 PH 5.6이하 의 산성비를 내리게 한다. 이 산성비는 삼림피해 어류감소 등 생태계를 파괴하고 콘 크리트 철재등 건축 자재물을 부사시킨다. 또한 바람에 의해 인접국가에도 막대한 피해를 주고 있다. 특히 폐가전제품의 PCB 접합부에 산성비가 접촉되면 Pb 이온이 용출되어 토양 및 수질오염, 인체피해 등 심각한 영향을 미치게 된다. 최근 이와관련 세계 각국의 규제 움직임이 활발해지고 있어, 본 논문은 전자기기 제품의 심장인 PCB 와 관계된 환경오염 대상물질의 규제동향과 심각성 및 이에 대한 환경피해 Mechanism 을 분석하여 실장기술에 있어서 총체적인 환경대응 방안을 모색하고자 한다.