• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.1
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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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.

• Proceedings of the KIEE Conference
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• 2001.11c
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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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• v.17 no.3
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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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• v.13 no.2
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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.

• Proceedings of the KIEE Conference
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• 1996.07a
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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.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.3
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• pp.256-262
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• 1998

The torque of SRM depends on phase current and the derivative of inductance. But the inductance of SRM is nonlinearly changed according to rotor position angle and phase current because of saturation in magnetic circuit, and it is difficult to control the desired torque. This paper proposes inductance modeling method using ANN(Artificial Neural Network) that is used to simulate the inductance which is nonlinearly varied with rotor position and current. The torque ripple is analyzed and input voltage and current condition to reduce torque ripple is simulated by inductance model.

• Journal of Power Electronics
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• v.14 no.6
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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.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.7
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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.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.6
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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.