• Journal of IKEEE
• /
• v.26 no.2
• /
• pp.265-270
• /
• 2022

This paper proposes the detection algorithm for switch open fault of asymmetric 6-phase PMSM based on stationary reference frame dq-axis currents. In this paper, target motor has an asymmetric structure in which two upper three windings have an electrical phase difference of 30° and a neutral point is separated. As a result, dual 3-phase PWM inverters and the detection techniques due to open failures of switch are definitely required. In this paper, the dual dq-axis current control method is used for driving the asymmetric 6-phase PMSM and the open fault switch should be detected by using variable all pass filter and low pass filter in order to detect the current amplitude. The effectiveness and usefulness of the proposed method is verified by several experiments.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.20 no.2
• /
• pp.56-66
• /
• 2016

Robustness is essential for model based FDI (Fault Detection and Isolation) and it is inevitable to have modeling errors and sensor signal noises during the process of FDI. This study suggests an improved method by applying NARX (Nonlinear Auto Regressive eXogenous) model and Kalman estimator in order to cope with problems caused by linear model errors and sensor signal noises in the process of fault diagnoses. Fault decision is made by the probability of the trend of gradually accumulated errors applying Fuzzy logic, which are robust to instantaneous sensor signal noises. Reliability of fault diagnosis is verified under various fault simulations.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.756-757
• /
• 2011

보호장치는 전력계통에 고장이 발생할 경우 신속 정확 하게 고장을 검출하여 고장부분을 계통으로부터 분리시킴으로써 각종 설비의 손상을 막고 정전구간을 최소화 하여 계통의 안정화를 향상시키는 장치이다. 현재 한전 및 발전사 뿐만아니라 수자원공사의 수도사업장에서도는 원격감시 제어를 통한 무인화와 함께 디지털보호계전기가 설치 운영되고 있다. 디지털 보호계전기는 기존의 기계식 보호계전기가 수행하는 보호기능보다 우수한 성능이 입증되었으며 최근 반도체 기술의 비약적 발전과 보호 알고리즘의 지속적인 개발로 보호계전기의 디지털화가 가속되고 있고 더욱 개선된 고성능, 다기능의 보호계전기 또는 IED가 산업현장에 적용되는 추세에 있다. 본 논문에서는 과전압 보호계전기와 부족전압 보호계전기의 기능 및 동작특성에 대하여 연구하였다.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.17 no.1
• /
• pp.59-70
• /
• 2022

In this paper, we proposed an active fault tolerant control (AFTC) method for the position control of a quadrotor with complete loss of effectiveness of one motor. We obtained the dynamics of a quadrotor using Lagrangian equation without small angle assumption. For detecting the fault on a motor, we designed a fault detection module, which consists of the fault detection and diagnosis (FDD) module and the fault detection and isolation (FDI) module. For the FDD module, we designed a nonlinear observer that observes the states of a quadrotor based on the obtained dynamics. Using the observed states of a quadrotor, we designed residual signals and set the appropriate threshold values of residual signals to detect the fault. Also, we designed an FDI module to identify the fault location using the designed additional conditions. To make a quadrotor track the desired path after detecting the fault of a motor, we designed a fault tolerant controller based on the multiple sliding surface control (MSSC) technique. Finally, through simulations, we verified the effectiveness of the proposed AFTC method for a quadrotor with complete loss of effectiveness of one motor.

• Journal of Institute of Control, Robotics and Systems
• /
• v.10 no.1
• /
• pp.1-9
• /
• 2004

Inertial navigation system with hardware redundancy must use FDI(Fault Detection and Isolation) method to remove the influence of faulty sensors. Until now, several FDI methods such as PSA(Parity Space Approach), GLT(Generalized Likelihood ratio Test) and OPT(Optimal Parity vector Test) method are generally used. However, because these FDI methods only consider the situation that the system has one faulty sensor, these methods cannot be directly adapted for the system with two faulty sensors. To solve this problem, in this paper, PSA method is analyzed and based on this result, new FDI method called EPSA is proposed to consider a detection and an isolation of two faulty sensors in inertial navigation system.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.13 no.6
• /
• pp.562-567
• /
• 2020

In this paper, this is a study on the correction of protection relays to monitor temporary power facilities for storage tanks especially transformers to block and protect faults such as insulation breakdown. When an abnormality such as a short circuit or a ground fault occurs in the power system, it is important to detect this quickly cut off the device and equipment in which the fault occurred and separate it from the power system to correct the protection relay so that it does not interfere with power supply. In addition the fault current calculation that accurately applies the fault type and the cause of the fault for protection cooperation will be the most important factor in the correction of the protection relay. For protection coordination a study was conducted on the method of coordination for protection of power facility protection for storage tanks such as over current relay, ground over current relay, under voltage relay, and ground over voltage relay applied to temporary.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.2
• /
• pp.169-179
• /
• 2010

Satisfying the same probability of loss of control and essentially two fail operative performance with a triplex computer architecture requires a lot of modification of the conventional redundancy management design techniques, previously employed in quadruplex digital flight control computer. T-50 FCS for triplex redundancy management design applied an advanced digital flight control architecture with an I/O controller which is functionally independent of the digital computer to achieve the same reliability and special failure analysis and isolation schemes for fail operational goals with a triplex configuration. The analysis results indicated that the triplex flight control system is to satisfy the safety requirement utilizing the advanced flight control techniques and the system performance of the implemented flight control system was verified by failure mode effect test.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.22 no.5
• /
• pp.13-21
• /
• 2018

Technology trends of onboard and ground health management system software for aircraft gas turbine engines are surveyed. The software has changed from ground based software for fault detection and identification to a model based health identification technology for onboard software. This advanced algorithm is currently under development in a technically advanced country while domestic research is on the birth stage. This paper suggested that the optimal development plan of the software considering current technology state.

• Journal of Institute of Control, Robotics and Systems
• /
• v.10 no.11
• /
• pp.1037-1043
• /
• 2004

In this paper, a new fault detection and isolation algorithm fur inertial sensor system is proposed. To identify the inertial sensor fault, single antenna GPS receiver is used as an effective redundancy source. To use GPS receiver as redundancy for the inertial sensors, the algorithm to estimate the attitude and acceleration using single antenna GPS receiver is adopted. By using Doppler shift of carrier phase signal and kinetic characteristics of aircraft, attitude information of aircraft can be obtained at the coordinated flight condition. Based on this idea, fault diagnosis algorithm for inertial sensors using single antenna GPS based attitude is proposed. For more effective FDI, decision variables considering the aircraft maneuver are proposed. The effectiveness of the proposed algorithm is verified through the numerical simulations.

• Journal of Institute of Control, Robotics and Systems
• /
• v.17 no.10
• /
• pp.960-966
• /
• 2011

In this paper, an $\mathfrak{H}$_/$\mathfrak{H}_{\infty}$ fault detection and isolation (FDI) observer design problem is investigated for discrete-time delayed systems. To that end, a bank consisting of the sensor's number of observers is introduced. Each residual should be sensitive to a certain partial group of faults, but robust against the disturbance as far as possible. We formulate this multiobjective FDI problem as $\mathfrak{H}$_/$\mathfrak{H}_{\infty}$ observers design problem. Sufficient design condition is expressed as iterative linear matrix inequalities. The fault is then detected and isolated by evaluating the residuals through an FDI decision logic. A computer simulation is provided for verification of the proposed technique.