• 제어로봇시스템학회논문지
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• 제6권5호
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• pp.367-375
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• 2000

It is proposed that the rotor time constant and inductance are compensated at the same time in the indirect vector control method of an induction motor. The proposed scheme compensates the rotor time constant using the difference between the Q-axis real stator current and estimated current that is calculated from the terminal voltage and current, and compensates inductance by using the difference between the D-axis real stator flux and estimated stator flux in the synchronous rotating reference frame. Although the rotor time constant and inductance vary at once, the proposed method compensates the rotor time constant and inductance with accuracy. In addition to, two variables can be compensated not only at the steady state condition, but also at the transient state, where the torque varies in a rectangular pulse waveform. Therefore, the performance of vector control is greatly improved as verified by experiment.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권6호
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• pp.254-261
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• 2003

This study investigates magnetic circuit design of the Single-phase Line-start Permanent Magnet Synchronous Motor (LSPM) to develop the characteristics in steady state. In this paper, the saliency ratio, that is the ratio of q-axial inductance to d-axial inductance, and the inductance difference between q-axial inductance and d-axial inductance are increased. Design factor is selected permanent magnet position and rotor diameter. The analysis method of the synchronous motor on d-/q- axis coordinates is used for the positive component and the equivalent circuit of the induction motor is applied for the negative component analysis. Back-emf and d-q- axial inductance is analyzed by using 2 dimensional Finite Element Method (FEM). Characteristic analysis results with variation of design factor are reflected magnetic circuit design of LSPM. The characteristics of design model are compared with the characteristic of initial model.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.311-313
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• 1996

In case of field weakening region, the dynamic behavior of the speed controller depends on the rotor flux level. In this region, the flux is decreased inversely proportional to the rotor speed. As the rotor flux is decreased, as the magnetizing inductance is increased. In this paper, the effect of this increased magnetizing inductance to the performance of vector control is illustrated. The stationary reference frame torque not including the magnetizing inductance is calculated by stationary stator flux, and the rotating reference frame torque including the magnetizing inductance is calculated by rotating rotor flux. If the magnetizing inductance value is constant, two torque values are same regardless of the flux-component current. However, if the magnetizing inductance is varied, those two values are different. The paper presents the new tuning scheme of the magnetizing inductance using the difference between the stationary and rotating torque. Computer simulation demonstrates the efficacy of the proposed scheme.

• 한국정보전자통신기술학회논문지
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• 제13권5호
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• pp.353-358
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• 2020

일반적인 나선형 인덕터의 경우에 비대칭 구조를 가짐에 따라 포트의 방향에 영향을 받게 된다. 본 논문에서는 단층이면서 대칭 구조를 가질 수 있는 나선형 인덕터를 제안하고 시뮬레이션 및 주파수 특성을 분석하였다. 일반적인 나선형 인덕터는 포트의 기준에 따라 주파수-인덕턴스 특성, 주파수-품질계수 특성, 자기공진주파수가 큰 차이를 보이는 반면에, 제안된 대칭 나선형 인덕터는 포트에 변함없이 2.7nH의 인덕턴스, 약 7.86의 품질계수, 약 14.1GHz의 자기공진주파수를 가진다. 이는 기존 일반적인 나선형 인덕터가 포트에 따라 큰 차이를 갖는 것과 비교하여 포트의 방향에 대한 영향이 적은 것을 확인할 수 있었다. 다만, 코일의 점유 면적에 비하여 상호 인덕턴스가 줄어들어 낮은 인덕턴스를 가지며, 인덕턴스 증가보다 코일의 저항이 더 증가하여 품질계수 또한 낮아짐을 확인할 수 있었다. 향후에는 2층 대칭 나선형 구조를 통하여 인덕턴스와 품질계수를 향상시킬 수 있을 것으로 기대된다.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.230-235
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• 2017

When the characteristics of a linear induction motor (LIM) are analyzed using finite element analysis (FEA), it is desirable to set the voltage source as an input. If the voltage source is set as an input in FEA, the leakage inductance and primary resistance of the equivalent circuit must be entered by direct calculation, and the magnetizing inductance and secondary reaction effects are directly considered in FEA. Exact calculation is necessary because the primary winding resistance and leakage inductance directly entered will have a significant effect on the LIM output. Therefore, in this study, we accurately calculated the primary leakage inductance and analyzed the resulting LIM characteristics. We calculated the leakage inductance using an analytical equation and FEA, and we confirmed the accuracy by comparing the results with the value experimentally calculated using a manufactured model. We also analyzed the instrument performance and thrust of the LIM as a function of the difference in the leakage inductance. Finally, we present the conclusions on the precise analysis based on the calculation of the leakage inductance.

• Journal of Magnetics
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• 제16권1호
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• pp.74-76
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• 2011

Interior permanent-magnet synchronous motors (IPMSMs) produce both magnetic and reluctance torques. The reluctance torque is due to the difference between the d- and q-axis inductances based on the geometric rotor structure. The steady-state performance analysis and precise control of the IPMSMs greatly depend on the accurate determination of the parameters. The three essential parameters of the IPMSMs are the armature flux linkage of the permanent magnet, the d-axis inductance, and the q-axis inductance. In the basic design step of an IPMSM, the inductance parameters are very important for determining the motor characteristics, such as the input voltage, torque, and efficiency. Thus, it is very important to accurately estimate the values of the motor inductances. The inductance parameters of IPMSMs have nonlinear characteristics along the magnet size because the iron core is saturated by the magnet and armature reaction fluxes. In this study, the inductance parameters were calculated using both the magnetic-equivalent-circuit method and the finite-element method (FEM). Then the calculated parameters were compensated by the saturation coefficient function, which was also calculated via the magnetic-equivalent-circuit method and FEM.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권6호
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• pp.263-272
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• 2001

The paper presents the design of a segmented type synchronous reluctance motor(SynRM) to increase its torque and power factor. The main feature of a segmented type synchronous reluctance motor is the flux barrier. Thus, the design process to find optimum value of various geometric parameters including flux barrier will be explained. Optimum value of each parameter is found where the d, q inductance difference and saliency ratio are maximized because these inductance characteristics are related to torque and power factor. Finite Element Analysis will be used to simulate motor characteristics. Analysis results of redesigned SynRM show higher saliency ratio over 10 and improved value of maximum power factor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.783-784
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• 2006

In case of a difference exist between the experimental value and estimated value of back-emf, there can be a difference of turn number or residual flux density of permanent maget of the motor. In order to presume the turn number, the average length for each coil is used to calculate the resistance. However in producing the motor, doc to the tension of coil, the outer diameter of coil becomes smaller, and then the resistance estimated by average length for each coil is not correct. Therefore in this paper, through the comparison of experiment value and estimated value of inductance, a method of presuming the turn number and PM's residual flux density of an IPM motor is presented. The inductance of IPM motor changes with the rotor position, therefore the rotor part is taken out and then the inductance in open circuit condition is measured. In the analytical calculation, 3D FEM(Finite Element Method) is used, which can consider the leakage flux of end turns in frinzing effect.

• Journal of Power Electronics
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• 제4권2호
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• pp.87-95
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• 2004

A new fast-response high-current clamp DC-DC converter circuit design is presented that will meet the requirements and features of the new generation of microprocessors and digital systems. The clamp in the proposed converter amplifies the current in case of severe load changes and is able to produce high slew rate of output current and capability to keep constant the output voltage. This proposed high-current clamp technique is theoretically loss less, low cost and easy to implement with simple control scheme. This is modified from a basic buck topology by replacing the output inductor with two magnetically coupled inductors. Inductors are difference in inductance, one has large inductance and other has small inductance. The inductor with small inductance will take over the output inductor during fast load transient. It speedup the output current slew rate and reduce the output voltage drop in the case of heavy burden load changes.

• 한국전자파학회논문지
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• 제23권6호
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• pp.669-681
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• 2012

본 논문에서는 헬리컬 코일을 이용하는 공진형 무선 전력 전송 시스템에서 새로운 상호 인덕턴스 계산식을 이용한 해석적 계산을 제안한다. 상호 인덕턴스 계산 과정 중에 중요한 변수의 look-up table을 수식화 하였다. 송 수신이 대칭인 구조에서 두 헬리컬 코일 간의 거리를 53 mm부터 500 mm까지 10 mm 간격으로 거리를 증가시키며, 공진 주파수와 삽입 손실에 대한 계산 결과와 실험 결과를 비교하였다. 실험 결과와 계산 결과의 공진 주파는 평균적으로 5.63 %의 차이를 보였다. 삽입 손실은 실험 결과와 290 mm에서 0.33 dB의 가장 작은 차이를 보였고, 평균적으로 2.25 dB의 차이를 보였다. 발룬을 사용하지 않았을 때의 실험 결과가 계산 결과와 더 근접한 결과를 보이는 것을 확인했다.