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The early detection of incipient faults is desirable in mission-critical applications such as shipboard propulsion drives. This paper presents an online condition-monitoring approach for detecting early stage faults in IGBTs. The proposed algorithm extracts important device features (i.e. on-state resistance, gate charge, etc.) and compares them to healthy values recorded over a range of operating...
This paper presents a newly developed algorithm for evaluating the health of an induction machine. The proposed algorithm is based on spectrum analysis of an impedance calculated using measured stator current and voltage signals. The main idea is to calculate the frequency spectrum of the impedance for each power phase and compare specific differences between phases. Experimental investigations show...
This paper proposes a novel on-board condition monitoring of the aging of solder layers in IGBTs for electric vehicle applications. The diagnostic technique makes use of the chip itself as a temperature sensor while current sensors are already in place for control purposes. An auxiliary power supply unit which can be created from the 12V battery and an in situ data-logger circuit is developed for...
This article describes observations about power MOSFET failures and degradation experienced during accelerated testing involving high temperature and high humidity stresses. The examined power MOSFETs were operated in commercial variable speed drives in flyback transformer topology as power switches. Known power MOSFET failure mechanisms are summarized and electrical stresses typical for the flyback...
Electrical machine condition monitoring is of particular important to factory efficiency and worker safety. A variety of signal analysis techniques exists for machine status diagnosis. This paper deals with remote diagnosis of electrical systems. Herein, we developed a remote monitoring system based on the Internet technology. The use of such system gives many advantages including minimum intervention...
Discontinuous conduction mode (DCM) boost power factor correction (PFC) converters have the advantages of zero-current turn-on for the boost-switch and no reverse recovery stress on boost-diode. When the converter switching frequency is constant, it has better EMI performance as well. In the proposed study, a novel approach is introduced. By using the new technique, IC'less PFC solution with less...
The aim of the present paper is to compare and evaluate different diagnostic means for the identification of the broken bar fault in delta connected double-cage induction motors. The work is carried out with FEM. The motors are studied at nominal load as well as under low load operation. The traditionally used diagnostic means such as: the current, torque and apparent power waveforms' spectrums are...
Even if the asynchronous machine is widely used in industrial process under speed variable, we have to monitor the process which is composed of an inverter and a motor in an enclosed space. Thus, the stator current is not accessible and the AC supply line current is only available to monitor the system in comparison to a motor connected directly to the power supply. In this paper, we focus our attention...
This paper discusses the use of an optimal wavelets approach for broken rotor bars diagnosis. In this paper, discrete wavelet coefficients (DWT) of stator current in a specific frequency band are derived and analyzed. Wavelets db8, db9, db10, sym7 and sym8 are compared to select a most optimal one. This approach facilitates the detection and diagnosis of broken rotor bar occurrence or even number...
This paper presents a new diagnosis approach for quantitative rotor faults evaluation in three-phase wound rotor induction machines. In the considered application, the rotor windings are supplied by a static converter for the control of active and reactive power flows exchanged between the machine and the electrical grid. Under speed or fault-varying conditions, the typical rotor fault frequency components,...
Early fault diagnosis and condition monitoring can reduce the consequential damage and breakdown maintenance, prolong the machine life and increase the performance of industrial systems. This paper describes a real fault detection problem of a high-power (3.2 MW) induction motor driving pumps in a heating plant. Steady-state vibration signals were collected and some characteristic low- and high- frequency...
On-line diagnosis of induction motors faults requires special, high speed hardware, such as DSP or FPGAs. Practical implementation of diagnosis algorithms in such a device must take into account the limited amount of memory available for storing sampled data, and for performing spectral analysis using the FFT. Another practical problem is the need to filter the mains component, whose leakage can hide...
This paper explores the efficiency of Spectral Kurtosis (SK) in the area of electrical machines diagnosis. In the literature, Spectral Kurtosis is mainly presented as a tool used to detect non-stationary components in a signal. However, classical use of SK is unsuitable for detection of new stationary components or slow evolutions in a spectrum. In order to detect different types of faults, three...
This paper presents a technique of induction motor's efficiency monitoring based on air-gap power and rotor loss estimation by Kalman filtering. A simplified model of three phase induction motor, with equivalent circuit of five elements, has been tested by the proposed technique with varying load torque and power to represent practical operations. Good agreement between the simulation and experimental...
This paper introduces a new way to extract the fault components of a signal by means of a new proposed filter based on the Sampling Theorem and the properties of Discrete Fourier Transform. The proposed method is able to extract fault components either in steady-state or in transient conditions. This paper also proposes a new way to compute the energy of a signal in the frequency domain by means of...
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