• 전기학회논문지
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• 제61권1호
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• pp.34-40
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• 2012

Flux linkage of phase windings or phase inductance is an important parameter in determining the behavior of a switched reluctance motor (SRM) [1-8]. Therefore, the accurate prediction of inductance at aligned and unaligned rotor positions makes a significant contribution to the design of an SRM and its analytical approach is not straightforward due to nonlinear flux distribution. Although several different approaches using a finite element analysis (FEA) or curve-fitting tool have been employed to compute phase inductance [2-5], they are not suitable for a simple design procedure because the FEA necessitates a large amount of time in both modeling and solving with complexity for every motor design, and the curve-fitting requires the data of flux linkage from either an experimental test or an FEA simulation. In this paper, phase inductance at aligned and unaligned rotor positions is estimated by means of numerical method and magnetic equivalent circuit as well, and the proposed approach is analytically verified in terms of the accuracy of estimated inductance compared to inductance computed by an FEA simulation.

• 전기학회논문지
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• 제61권12호
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• pp.1836-1842
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• 2012

Torque is proportional to the rate of change of inductance in a switched reluctance motor (SRM), and hence, phase inductance is an important parameter in determining the behavior of an SRM. Therefore, the accurate prediction of inductance with respect to rotor position makes a significant contribution to designing an SRM and its analytical approach is not straightforward due to nonlinear flux distribution. Although several different approaches using a finite element analysis (FEA) or curve-fitting tool have been employed to compute phase inductance [2-5], they are not suitable for a simple design procedure because the FEA necessitates a large amount of time in both modeling and solving with complexity for every motor design, and the curve-fitting requires the data of flux linkage from either an experimental test or an FEA simulation. In this paper, phase inductance is predicted by means of a permeance method, and the proposed approach is analytically verified in terms of the accuracy of estimated inductance compared to inductance obtained by FEA.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.22-25
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• 2001

In this paper, a fuzzy advance angle control method is described to drive an industrial low voltage SRM (Switched Reluctance Motor) for 10kW forklift truck. SRM has a highly non-linear characteristic that is due to change the rotor and stator. And low voltage SRM is designed that its phase resistance and phase inductance is very low to inject high current into the phase windings. In this reason, the proper current control is necessary to drive the low voltage SRM efficiently. SRM has positive torque at increasing inductance region and negative torque at decreasing inductance region. Due to this reason, the current has to be built up in the increasing phase inductance part as soon as possible. Therefore, the phase switch must be turned on before the phase inductance increases, and this angle is called as the advance angle. Also, the phase current has to be dropped before the phase inductance decreases. Fuzzy logic is a flexible and general-purposed method of implementing non-linear functions and as such it is useful in control applications. Consequently, we designed a fuzzy advance angle controller to control the phase current appropriately.

• Journal of Magnetics
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• 제17권3호
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• pp.196-199
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• 2012

This paper presents the analytical calculation of winding inductance for a single-phase brushless DC machine based on the magnetic circuit concept. The machine is used in the low power range of applications, such as ventilation fans, due to its simplicity and low cost. Since flux linkage is proportional to inductance, the calculation of winding inductance is of central importance. By comparison with experimental and analytical values, it is shown that proposed analytical expression is able to effectively predict the winding inductance of single-phase brushless DC machines at the design stage.

• Journal of Power Electronics
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• 제13권2호
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• pp.264-274
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• 2013

A new sensorless position estimation method for switched reluctance motor (SRM) drives is presented in this paper. This method uses the change of the slope of the phase inductance to detect the aligned position. Since the aligned positions for successive electrical cycle of each phase are apart by a fixed mechanical angle $45^{\circ}$ in the case of 12/8 SRM, the speed of the machine can be calculated to estimate the rotor position. Since no prior knowledge of motor parameters is required, the method is easy for implementation without adding any additional hardware or memory. In order to verify the validity of this technique, effects such as changes in the advanced angle and phase lacking faults are examined. In addition, an inductance threshold based sensorless starting scheme is also proposed. Experimental results demonstrate the validity of the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.31-33
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• 1996

A SRM develops its torque according to the inductance variation as the rotor position and the phase current. The variation of the inductance and the phase current plays an important role in output characteristics. Predicting and calculating the inductance is invaluable in the study of SRM. This paper suggests the estimation method of inductance as variation of phase current and rotor position considering magnetic saturation of motor core. This method is also applied to full-pitched winding SRM.

• 전력전자학회논문지
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• 제3권3호
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• pp.256-262
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• 1998

SRM의 토오크는 상전류의 제곱과 인덕턴스 기울기에 비례한다. 그러나 SRM의 인덕턴스는 자기회로의 포화현상을 회전자위치각과 상전류에 따라 비선형적으로 변화하여 순시적으로 원하는 토오크를 제어하기 어렵다. 본 논문에서는 비선형 해석에 우수한 성능을 보이는 신경회로망을 이용하여 인덕턴스를 모델링하는 방법을 도입하여 인덕턴스의 변화를 관측하였다. 그리고 이를 이용하여 맥동토오크를 해석하였으며 맥동토오크를 저감하는 전압, 전류조건을 시뮬레이션하였다.

• Journal of Power Electronics
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• 제14권6호
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• pp.1243-1253
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• 2014

The phase inductance of a switch reluctance motor (SRM) is significantly nonlinear. With different saturation conditions, the phase inductance shape is clearly changed. This study focuses on the relationship between coefficient and current in an inductance model with ignored harmonics above the order of 3. A position estimation method based on the variable coefficient inductance model is proposed in this paper. A four-quadrant sensorless control system of the SRM drive is constructed based on the relationship between variable coefficient inductance and rotor position. The proposed algorithms are implemented in an experimental SRM test setup. Experimental results show that the proposed method estimates position accurately in operating two/four-quadrants. The entire system also has good static and dynamic performance.

• 대한전기학회논문지
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• 제34권7호
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• pp.267-275
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• 1985

The finite element method for calculating single phase transformer inductance is presented in this paper. There are three basic definitions of saturated transormer inductance. The set of nonlinear finite element equations is solved by the Newton-Raphson method which assures nearly quadratic convergence of the iteration process. The effect of perturbation of currents of this transformer is used to calculate the saturated winding inductance. This approach is used to calculate the apparent, effective and incremental inductance of single phase transformer. The apparent inductance is in good agreement with resting result. The approach enabled one to study the variation of winding inductance according to the saturation levels in the core at any operating point.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권6호
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• pp.287-293
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• 1999

A new excitation method of switched reluctance motor drive is described in this paper. This excitation method produces reluctance torque by mutual action between two phases as well as conventional self reluctance torque due to two phase excitation at a time. In other words, the change of self inductance and mutual inductance are used to produce torque. This paper suggests the operational principle, the mechanism of torque product of switched reluctance motor with two phase excitation. The acoustic noise characteristics of two phase excitation method are described against that of conventional excitation method. The energy conversion ratio is increased because the next phase is excited following one phase excited at the two phase excitation method. Acoustic noise is lower than that of conventional SRM because one of the next two phase is excited already when torque develope.