• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.4
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• pp.367-375
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• 2013

The mechanical vibration of a PM synchronous motor at low speeds due to the back emf harmonics may be serious problems in some application such as MDPS(Motor driven power steering), electric vehicles. In this paper, torque ripple reduction for an interior PM synchronous motor including back emf harmonics is proposed. The dq flux linkage harmonics of the permanent magnet are estimated on real time by using the dq currents of the real system and the model of the MRAS observer. Based on the estimated flux linkage harmonics, the dq harmonic currents for reducing the torque ripples are compensated on the dq reference currents. The estimation of the flux linkage harmonics by the MRAS observer and the torque ripple reduction of the proposed algorithm was verified by the simulation and experiment.

• Journal of Power Electronics
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• v.17 no.5
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• pp.1223-1230
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• 2017

The back emf harmonics of a permanent magnet (PM) synchronous motor is a major source of torque ripple. For torque control applications including column fitted MDPS (motor driven power steering) systems, it is essential to reduce the mechanical vibrations due to torque ripples at low speeds. In this paper, a torque ripple reduction algorithm for interior PM synchronous motors is proposed. The harmonic currents that cancel the $6^{th}$ order torque harmonic are added to the nominal dq currents for MTPA (maximum torque per ampere) operation. The compensated harmonic currents are derived from flux linkage harmonics based on a FFT analysis of the back emf harmonics. Simulation and experimental results verify that the $6^{th}$ order torque harmonic and THD of the torque ripple are reduced by compensating the dq harmonic currents.

• Journal of Electrical Engineering and Technology
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• v.10 no.2
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• pp.539-544
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• 2015

FEA was used to analyze inductance and torque of IPMSM. Torque and inductance are analyzed on the dq-axis. It was shown that Ld and Lq have harmonic components, and magnitude as well as phase of the harmonics varies according to the current values. This paper shows the relationship between these inductance harmonics and the 6th harmonic component of torque.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.205-207
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• 1994

This paper presents an analyzing method of the distortion factor of the output voltage in generator on the basis of the stator coil flux linkage calculation. In the simulation, 2 dimensional finite clement method is used considering the rotor movement. As an application of the proposed method, we calculated the harmonics of air gap flux and the output voltage in the 150KW class synchronous generator.

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.13-16
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• 1996

A new instantaneous torque control technique is presented for a high performance control of a permanent magnet synchronous motor. Using the model reference adaptive system technique, the linkage flux of the motor is estimated and the torque is instantaneously controlled by the proposed torque controller combining with a variable structure control and space vector PWM. The proposed torque control provides the advantage of reducing the torque pulsation caused by the flux harmonics. This control strategy is applied to the high torque PM synchronous motor drives for direct drive systems and is implemented by using a software of the DSP TMS320C30. The experiments are carried out for this system and the results well demonstrate the effectiveness of the proposed control.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.254-260
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• 2013

This paper deals with electromagnetic characteristics of IPMSM (Interior Permanent Magnet Synchronous motor) caused by field weakening current control. In order to extend operation speed, field weakening current control is generally used in IPMSM operation. During field weakening, distorted linkage fluxes are resulted by saturation of core material. Therefore, distorted input voltage waveform is required for sinusoidal current input. As the current vector angle increases for field weakening, distortion of linkage flux and back-emf becomes significant. This situation is analyzed by 2-dimensional finite element analysis and verified by experiment. With the results, it is concluded that motor parameters, such as linkage flux by permanent magnet, phase resistance, d-q axis inductance, are insufficient for estimating required voltage for given speed especially in field weakening and additional considerations for increased harmonics of voltage are required.

• Journal of the Korean Magnetics Society
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• v.5 no.2
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• pp.103-108
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• 1995

We propose an analyzing method of the harmonics of output voltage in salient pole syochronous generator. In simulation, 2-D finite elerrent method is used for calculating the stator coil flux linkage considering the rotor movement. As an application of the proposed method, we calculated the harrronics of output voltage in the 150 kw class syochromus generator and compared it with the experirrental result.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.3
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• pp.65-78
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• 2013

To analyze influences under open fault conditions in switching devices, an integrated simulation and condition monitoring scheme for a permanent magnet synchronous generator (PMSG) based variable speed grid-connected wind turbine system are presented. Among various faults in power electronics components, the open fault in switching devices may arise when the switches are destructed by an accidental over current, or a fuse for short protection is blown out. Under such a faulty condition, the grid-side inverter as well as the generator-side converter does not operate normally, producing an increase of current harmonics, and a reduction in output and efficiency. As an effective way for a condition monitoring of generation system by online basis without requiring any diagnostic apparatus, the estimation schemes for generated voltage, flux linkage, and stator resistance are proposed and the validity of the proposed scheme is proved through comparative simulations.