• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1167-1171
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• 1992

A predictive current control in the synchronous reference frame with the back EMF estimation using the previous voltages and currents is proposed. To reduce the torque ripple produced by harmonics in the air gap flux, the q-axis current is compensated using the estimated torque constant. The effectiveness of the proposed control is compared to the conventional control scheme through the simulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.1
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• pp.37-42
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• 2013

This paper deals with Wound Rotor Synchronous Motor (WRSM) purposely designed for Integrated Starter and Generator (ISG) installed in 42V automotive electrical system. Not only design objective and specifications of WRSM, but its adaptive design to minimize torque ripple and back-EMF Total Harmonics Distortion (THD) are considered. Furthermore, design characteristics of designed prototype have been investigated numerically in terms of torque, back EMF, loss, and efficiency, which are verified by performance comparison with Interior Permanent Magnet Synchronous Machine based on Finite Element Analysis (FEA).

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.985-986
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• 2011

This paper deals with d-q axis equivalent circuit analysis of IPMSM(Interior Permanent Magnet Synchronous Motors) considering voltage harmonics. In the field weakening region, as the current vector angle increased, back-emf contains large harmonics, therefore, significant underestimation of voltage or overestimation of speed can be occurred from the conventional d-q axis equivalent circuit analysis. In order to consider the effects of voltage harmonics, a harmonic coefficient is introduced and verified by experiments.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.27-29
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• 2005

This paper studies particularly applicable method for sensorless Permanent Magnet Brushless DC(PMBLDC) Motor drive system. The waveform of the motor internal voltages (or back emf) contains a fundamental and higher order frequency harmonics. Therefore the third harmonics. component is extracted from the stator phase voltage. The resulting third harmonic signal keeps a constant phase relationship with the rotor flux for any motor speed and load condition. In addition, a simple starting method and a speed estimation approach are also proposed.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.67-69
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• 2002

This paper present increasing of Power density of slotless PMLSM by inserting core between phase winding. PM width is changed and PM is divided into two part to reduce and eliminate high order space harmonics affecting torque ripple. Flux density, back EMF, inductance, thrust, normal and detent force are computed by 2D FEM, and analysis values are compared with each other.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.12
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• pp.718-724
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• 2004

This study investigates the design factors of Interior Permanent Magnet Synchronous Motor(IPMSM) which is applied to Hybrid electric vehicle as a driving power. Recently, there are many studies of IPMSM for application to Hybrid Electric Vehicle, because IPMSM has characteristics of high torque, high power density and high efficiency which come from reluctance torque due to difference of inductance as well as magnet torque. This study analyzes the inductance and design characteristics of IPMSM by using finite element method and focuses on design and analysis of IPMSM which can operates with high efficiency at low speed range. For this embodiment, magnet shape is changed from conventional block type to arc type without any change of outline dimension of motor and this change of magnet shape makes it possible to increase back EMF and sinusoidal waveform. Analysis results are verified by test of improved and embodied motor. As a test result , increased back EMF and sharply decrease of harmonics are secured and through this contribution of reduced fuel consumption of Hybrid electric vehicle is expected.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.1
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• pp.66-74
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• 2012

This paper propose a improved direct torque control(DTC) system for improving operation of five-phase squirrel-cage induction motor(IM). A five-phase IM drives present unique characteristics due to the additional degrees of freedom and also drives possess many others advantage compared with the traditional three-phase motor drive system, such as reducing a amplitude of torque pulsation and increasing the reliability. In order to maximize the torque per ampere, the proposed motor has concentrated windings and the produced back-electromotive force(EMF) is almost trapezoidal, and the motor is supplied with the combined sinusoidal plus third harmonic of currents, there is necessary to controlled 3rd harmonic current. Also a DTC method is advantageous when it is applied to the five-phase IM, because the five-phase inverter provides 32 space vectors in comparison to 8 space voltage vectors into the three-phase inverter drive system. For presenting the superior performance of the proposed DTC, experimental results of speed control are presented using a 32-bit fixed point TMS320F2812 DSP with 1.5[hp] IM.

• Journal of Electrical Engineering and Technology
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• v.11 no.4
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• pp.878-888
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• 2016

Cogging torque has a negative impact on the operation of permanent magnet machines by increasing torque ripple, speed ripple, acoustic noise and vibration. In this paper Magnet Shifting Method has been used as a tool to reduce the cogging torque in inset Line Start Permanent Magnet Synchronous Motor (LSPMSM). It has been shown that Magnet Shifting Method can effectively eliminate several lower-order harmonics of cogging torque. In order to implement the method, first the expression of cogging torque is studied based on the Fourier analysis. An analytical expression is then introduced based on Permanent Magnet Shifting to reduce cogging torque of LSPMS motors. The method is applied to some existing machine designs and their performances are obtained using Finite Element Analysis (FEA). The effect of magnet shifting on pole mmf (magneto motive force) distribution in air gap is discussed. The side effects of magnet shifting on back-EMF, core losses and torque profile distortion are taken into account in this investigation. Finally the experimental results on two prototypes 24 slot 4 pole inset LSPMS motors have been used to validate the theoretical analysis.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.10
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• pp.494-500
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• 2001

This paper presents the shape optimization to minimize the BEMF(Back Electro-Motive Force) harmonics of PM type synchronous generators. RSM(Response Surface Methodology) is well adapted to make analytical model for a complex problem considering a lot of interaction of design variables. In this paper, RSM is used to find the optimal solution. The 2D-Finite Element Method is used to obtain the observer data of the BEMF and SQP(Sequential Quadratic Problem method) is used to solve the constrained nonlinear optimization problem.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.57-59
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• 2001

This paper presents the shape optimization to minimize the BEMF(Back Electro-Motive Force) harmonics of PM type synchronous generators. RSM(Response Surface Methodology) is used to find the optimal solution. We used the 2D-Finite Element Method to obtain the observed data of the BEMF and SQP(Sequential Quadratic Problem method) is used to solve the constrained nonlinear optimization problem.