• Proceedings of the KSR Conference
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.336-343
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• 2000

This paper proposes the failsafe control logic. which has applied to the voting on the TMR system by using FPGA The self-detection circuit is also designed for detecting a characteristic of fault at TMR system. The fault producing in the self-detection system is largely classified among an intermittent fault, a transient fault and a permanent fault. If it is happened to the permanent fault, the system can be failed. Therefore, it is designed the logic circuit which is not transferred the permanent fault to the system after shut off output. The control logic of the Fail Safe proposed in the paper is required for a circuit integrate of device to minimize the failure happened. Therefore, it makes to design FPGA with modeling of VHDL. The circuit of the Fail Safe of TMR system is able to apply to nuclear system, rail-way system, aerospace and aircraft system which is required for high reliability.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1566-1574
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• 2017

When the inter-turn short circuit (ITSC) fault occurs, the distortion of the magnetic field is serious. The motor loss variations of each part are obvious, and the motor temperature field is also affected. In order to obtain the influence of the ITSC fault on the motor temperature distribution, firstly, the normal and the fault finite element models of the permanent magnet synchronous motor (PMSM) were established. The magnetic density distribution and the eddy current density distribution were analyzed, and the mechanism of loss change was revealed. The effects of different forms and degrees of the fault on the loss were obtained. Based on the loss analysis, the motor temperature field calculation model was established, and the motor temperature change considering the loop current was analyzed. The influence of the fault on the motor temperature distribution was revealed. The sensitivity factors that limit the motor continuous operation were obtained. Finally, the correctness of the simulation was verified by experiments. The conclusions obtained are of great significance for the fault and high temperature demagnetization of the permanent magnet analysis.

• Proceedings of the KIEE Conference
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1366-1368
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• 1999

With conventional single pole auto-reclosure (SPAR), unsuccessful reclosure using a fixed dead time in the case of transient fault, or reclosure onto a permanent fault. may aggravate the potential damage to the system and equipment. In this respect, the research is needed to implement SPAR effectively. In this paper, we present a wavelet transform approach to detect and discriminate between transient fault and permanent fault in transmission lines.

• Journal of Electrical Engineering and Technology
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• 제13권4호
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• pp.1614-1622
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• 2018

The research related to fault diagnosis in permanent magnet synchronous motors (PMSMs) has attracted considerable attention in recent years because various faults such as permanent magnet demagnetization and short-circuited turns can occur and result in unexpected failure of motor related system. Several conventional current and back electromotive force (BEMF) analysis techniques were proposed to detect certain faults in PMSMs; however, they generally deal with a single fault only. On the contrary, cases of multiple faults are common in PMSMs. We propose a fault diagnosis method for PMSMs with single and multiple combined faults. Our method uses three phase BEMF voltages based on the fast Fourier transform (FFT), support vector machine(SVM), and visualization tools for identifying fault types and severities in PMSMs. Principal component analysis (PCA) and t-distributed stochastic neighbor embedding (t-SNE) are used to visualize the high-dimensional data into two-dimensional space. Experimental results show good visualization performance and high classification accuracy to identify fault types and severities for single and multiple faults in PMSMs.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제67권3호
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• pp.365-373
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• 2018

In this paper, inter-turn fault diagnosis of the interior permanent magnet synchronous motor (IPMSM) is performed in offline state by linking the finite element analysis (FEA) tool and control simulation tool. In order to diagnose the inter-turn fault, it is important to select the current value to determine the fault. First, the basic principles for inter-turn fault diagnosis of IPMSM are explained and co-analysis model for fault diagnosis is constructed. Further, in order to select the appropriate high frequency voltage, the change of the current value to be judged as failure was analyzed at various voltage and frequency conditions, and the change of the current value according to the number of the failed windings was analyzed. Finally, the current value to be judged as failure is selected.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제66권2호
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• pp.394-401
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• 2017

Fault diagnosis is important due to the increasing demand of using interior permanent magnet synchronous machines (IPMSMs). In particular, an interturn fault is one of the most frequent electrical faults in IPMSMs. This paper proposes a fault indicator for diagnosis of interturn faults in IPMSMs. The fault indicator is developed by negative-sequence impedance. The effectiveness of the fault indicator to diagnose interturn faults was verified through various fault conditions.

• Journal of Power Electronics
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• 제13권6호
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• pp.985-990
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• 2013

This paper proposes a novel fault diagnosis scheme using parameter estimation of the stator resistance, especially in the case of the open-phase faults of PMSM drives. The stator resistance of PMSMs can be estimated by the recursive least square (RLS) algorithm in real time. Fault diagnosis is achieved by analyzing the estimated stator resistance of each phase according to the fault condition. The proposed fault diagnosis scheme is implemented without any extra devices. Moreover, the estimated parameter information can be used to improve the control performance. The feasibility of the proposed fault diagnosis scheme is verified by simulation and experimental results.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제66권3호
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• pp.568-574
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• 2017

This paper proposes a demagnetization fault diagnosis method for interior permanent magnet synchronous motors(IPMSMs). In particular, a demagnetization fault is one of the most frequent electrical faults in IPMSMs. This paper proposes an estimation method for permanent magnet flux. The method is based on linear interpolation. The effectiveness of the proposed method for diagnose demagnetization faults is verified through various operating conditions by finite element simulation.

• Proceedings of the KIEE Conference
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1130-1132
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• 1999

This paper presents the feature extraction of fault current related to the multi-shot reclosing scheme in the power distribution system. Fourier transform is used to extract the feature of the fault current waveform in the case of the temporary fault and the permanent fault. After the waveform is analyzed using Fourier transform, the magnitude spectrum and the relative variation of THD are calculated. These results are that the relative variation of THD is great in the temporary fault and is little in the permanent fault.

• The Transactions of the Korean Institute of Power Electronics
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• 제20권4호
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• pp.305-312
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• 2015

In this study, inter-turn short fault models of interior permanent magnet synchronous motors (IPMSM) are developed by adding saliency modeling to surface-mounted permanent magnet motor models. The saliency model is obtained using the deformed flux models based on both fault-winding flux information and inductance variations caused by cross-flux linkages that depend on the distribution of the same phase windings. By assuming the balanced three-phase current injection, we obtain the positive and negative sequence voltages and the fault current in the positive and the negative synchronous reference frames. The output torque model is developed by adding the magnet and the reluctance torque, which are derived from the developed models. To verify the proposed IPMSM model with an inter-turn short fault, finite element method-based simulation and experimental measurement results are presented.