scholarly journals Detection of Inter-Turn Faults in Multi-Phase Ferrite-PM Assisted Synchronous Reluctance Machines

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2733 ◽  
Author(s):  
Carlos Candelo-Zuluaga ◽  
Jordi-Roger Riba ◽  
Carlos López-Torres ◽  
Antoni Garcia
Keyword(s):  
Early Stage ◽  
Short Circuit ◽  
Operating Conditions ◽  
Spectral Content ◽  
Stator Current ◽  
Zero Sequence ◽  
Motor Current Signature Analysis ◽  
Diagnosis Method ◽  
Multi Phase ◽  
Zero Sequence Voltage

Inter-turn winding faults in five-phase ferrite-permanent magnet-assisted synchronous reluctance motors (fPMa-SynRMs) can lead to catastrophic consequences if not detected in a timely manner, since they can quickly progress into more severe short-circuit faults, such as coil-to-coil, phase-to-ground or phase-to-phase faults. This paper analyzes the feasibility of detecting such harmful faults in their early stage, with only one short-circuited turn, since there is a lack of works related to this topic in multi-phase fPMa-SynRMs. Two methods are tested for this purpose, the analysis of the spectral content of the zero-sequence voltage component (ZSVC) and the analysis of the stator current spectra, also known as motor current signature analysis (MCSA), which is a well-known fault diagnosis method. This paper compares the performance and sensitivity of both methods under different operating conditions. It is proven that inter-turn faults can be detected in the early stage, with the ZSVC providing more sensitivity than the MCSA method. It is also proven that the working conditions have little effect on the sensitivity of both methods. To conclude, this paper proposes two inter-turn fault indicators and the threshold values to detect such faults in the early stage, which are calculated from the spectral information of the ZSVC and the line currents.

scholarly journals Analysis of Effective Three-Level Neutral Point Clamped Converter System for the Bipolar LVDC Distribution

Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 691 ◽  
Author(s):  
Ju-Yong Kim ◽  
Ho-Sung Kim ◽  
Ju-Won Baek ◽  
Dong-Keun Jeong
Keyword(s):  
Distribution System ◽  
Low Voltage ◽  
Balance Control ◽  
Short Circuit ◽  
Renewable Energy Sources ◽  
Neutral Point ◽  
Extreme Load ◽  
Zero Sequence ◽  
Zero Sequence Voltage ◽  
Short Circuit Condition

Low-voltage direct current (LVDC) distribution has attracted attention due to increased DC loads, the popularization of electric vehicles, energy storage systems (ESS), and renewable energy sources such as photovoltaic (PV). This paper studies a ±750 V bipolar DC distribution system and applies a 3-level neutral-point clamped (NPC) AC/DC converter for LVDC distribution. However, the 3-level NPC converter is fundamental in the neutral-point (NP) imbalance problem. This paper discusses the NP balance control method using zero-sequence voltage among various solutions to solve NP imbalance. However, since the zero-sequence voltage for NP balance control is limited, the NP voltage cannot be controlled to be balanced when extreme load differences occur. To maintain microgrid stability with bipolar LVDC distribution, it is necessary to control the NP voltage balance, even in an imbalance of extreme load. In addition, due to the bipolar LVDC distribution, the pole where a short-circuit condition occurs limits the short current until the circuit breaker operates, and a pole without a short-circuit condition must supply a stable voltage. Since the conventional 3-level NPC AC/DC converter alone cannot satisfy both functions, an additional DC/DC converter is proposed, analyzed, and verified. This paper is about a 3-level NPC AC/DC converter system for LVDC distribution. It can be used for the imbalance and short-circuit condition in bipolar LVDC distribution through the prototype of the 300 kW 3-level NPC AC/DC converter system and experimented and verified in various conditions.

scholarly journals Motor Current Signature Analysis-Based Permanent Magnet Synchronous Motor Demagnetization Characterization and Detection

Machines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 35
Author(s):  
Manel Krichen ◽  
Elhoussin Elbouchikhi ◽  
Naourez Benhadj ◽  
Mohamed Chaieb ◽  
Mohamed Benbouzid ◽  
...  
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnets ◽  
Early Stage ◽  
Permanent Magnet Synchronous Motor ◽  
Cost Effective ◽  
Operating Conditions ◽  
Signature Analysis ◽  
Motor Current ◽  
Motor Current Signature Analysis ◽  
Current Signature

Neodymium-boron (NdFeB) permanent magnets (PMs) have been widely studied in the past years since they became the material of choice in permanent magnet synchronous machines (PMSMs). Although NdFeB PMs have a better energy density than other types of magnets and are cost-effective, their magnetization is very sensitive to the PMSM operating conditions, in particular temperature, where the irreversible demagnetization degree increases over time. Therefore, it is important to characterize and diagnose demagnetization at an early stage. In this context, this paper proposes a two-step analysis study dealing with both uniform and partial demagnetization. A 2D finite element method-based (FEM) approach is used for demagnetization characterization, and then a PMSM motor current signature analysis (MCSA) approach, based on fast Fourier transform (FFT), is considered where fault cases harmonics are considered as faults indices to detect demagnetization. In some situations, the proposed two-step approach achieved results that clearly allow distinguishing and characterizing demagnetization. Indeed, a local demagnetization introduces specific sub-harmonics while a uniform demagnetization leads to the current amplitude increase for a given torque.

Magnetic Field Finite Element Analysis of Generator with Rotor Inter-Turn Short-Circuit Fault

2014 ◽  
Vol 707 ◽  
pp. 343-347
Author(s):  
Yong Gang Li ◽  
Bing Han
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Magnetic Flux ◽  
Flux Density ◽  
Early Stage ◽  
Short Circuit ◽  
Air Gap ◽  
Operating Conditions ◽  
Magnetic Flux Density ◽  
Short Circuit Fault

Rotor inter-turn short-circuit is a common fault in generator and it is a research hotspot to identify the fault at its early stage. Considering the disadvantage of circuit analytical method, this paper establishes a 2D transient finite element electromagnetic-circuit coupling model, and calculates the magnetic field at normal and fault situations through the powerful post-processing function of ANSOFT, then magnetic flux density cloud pictures and air-gap magnetic flux density curves of different operating conditions are got. Using MATLAB to analyze and deal with the air-gap flux density cures, we can get the differences of faults in different levels and different positions, which provide a basis for further study of rotor inter-turn short-circuit fault.

scholarly journals Three-Level Unidirectional Rectifiers under Non-Unity Power Factor Operation and Unbalanced Split DC-Link Loading: Analytical and Experimental Assessment

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5280
Author(s):  
Davide Cittanti ◽  
Matteo Gregorio ◽  
Eugenio Bossotto ◽  
Fabio Mandrile ◽  
Radu Bojoi
Keyword(s):  
Power Factor ◽  
Point Charge ◽  
Operating Conditions ◽  
Input Current ◽  
Modulation Index ◽  
Complete Analysis ◽  
Unity Power Factor ◽  
Phase Current ◽  
Zero Sequence ◽  
Zero Sequence Voltage

Three-phase three-level unidirectional rectifiers are among the most adopted topologies for general active rectification, achieving an excellent compromise between cost, complexity and overall performance. The unidirectional nature of these rectifiers negatively affects their operation, e.g., distorting the input currents around the zero-crossings, limiting the maximum converter-side displacement power factor, reducing the split DC-link mid-point current capability and limiting the converter ability to compensate the low-frequency DC-link mid-point voltage oscillation. In particular, the rectifier operation under non-unity power factor and/or under constant zero-sequence voltage injection (i.e., when unbalanced split DC-link loading occurs) typically yields large and uncontrolled input current distortion, effectively limiting the acceptable operating region of the converter. Although high bandwidth current control loops and enhanced phase current sampling strategies may improve the rectifier input current distortion, especially at light load, these approaches lose effectiveness when significant phase-shift between voltage and current is required and/or a constant zero-sequence voltage must be injected. Therefore, this paper proposes a complete analysis and performance assessment of three-level unidirectional rectifiers under non-unity power factor operation and unbalanced split DC-link loading. First, the theoretical operating limits of the converter in terms of zero-sequence voltage, modulation index, power factor angle, maximum DC-link mid-point current and minimum DC-link mid-point charge ripple are derived. Leveraging the derived zero-sequence voltage limits, a unified carrier-based pulse-width modulation (PWM) approach enabling the undistorted operation of the rectifier in all feasible operating conditions is thus proposed. Moreover, novel analytical expressions defining the maximum rectifier mid-point current capability and the minimum peak-to-peak DC-link mid-point charge ripple as functions of both modulation index and power factor angle are derived, the latter enabling a straightforward sizing of the split DC-link capacitors. The theoretical analysis is verified on a 30 kW, 20 kHz T-type rectifier prototype, designed for electric vehicle ultra-fast battery charging. The input phase current distortion, the maximum mid-point current capability and the minimum mid-point charge ripple are experimentally assessed across all rectifier operating points, showing excellent performance and accurate agreement with the analytical predictions.

Vibration Fault Diagnosis Method Based on Compositive Characteristics of Rotor Vibration and Stator Current

2007 ◽  
Author(s):  
Shuting Wan ◽  
Yonggang Li
Keyword(s):  
Fault Diagnosis ◽  
Short Circuit ◽  
Air Gap ◽  
Vibration Characteristics ◽  
Rotor Vibration ◽  
Stator Current ◽  
Dynamic Eccentricity ◽  
Diagnosis Method ◽  
Current Characteristics ◽  
Rotor Winding

Rotor vibration characteristics are first analyzed, when the rotor winding inter-turn short circuit fault, the air-gap dynamic eccentricity fault, the air-gap static eccentricity fault and the imbalance fault occurs. Next, the generator stator current characteristics on the faults also were analyzed, the results show that the faults can’t be diagnosed based only on rotor vibration characteristics or stator current characteristics. But considering the differences of compositive characteristics of the rotor vibration and stator current caused by different rotor faults, a new method of generator vibration fault diagnosis, based on compositive characteristics, is developed. Finally, the rotor vibration and stator current of a type SDF-9 generator is measured in the laboratory to verify the theoretical analysis presented above.

Detecting of Multi Phase Inter Turn Short Circuit in the Five Permanent Magnet Synchronous Motor

2016 ◽  
Vol 17 (5) ◽  
pp. 583-595 ◽  
Author(s):  
N. Yassa ◽  
M. Rachek ◽  
A. Djerdir ◽  
M. Becherif
Keyword(s):  
Permanent Magnet ◽  
Short Circuit ◽  
Permanent Magnet Synchronous Motor ◽  
Induction Machine ◽  
State Equations ◽  
Power Spectral ◽  
Fault Severity ◽  
Diagnosis Method ◽  
Multi Phase ◽  
Short Circuit Fault

Abstract This paper proposes a general model of five phase permanent magnet synchronous machine (PMSM) which is capable of representing the multiphase Inter Turn Short Circuit (ITSC) occurring in several phase simultaneously this model is based on a coupled magnetic circuit approach leading to a differential equations system goveming the induction machine behavior. The obtained time-differential state equations system is implemented under Matlab environment and numerically solved using the fourth order Rung-Kutta method with variable step time corrected at each rotor displacement through the electromagnetic torque. Also, Fast Fourier Transform and (FFT) analysis is performed to the phase current signal to detect the frequency spectrum, Power Spectral Density (PSD) is chosen as a classification method. Its efficiency depends on its ability to discriminate between various faults generating the same range of harmonics in the stator current spectrum and on its ability to evaluate the fault severity. So, in order to improve the efficiency of these diagnosis methods, one needs a relatively accurate model to simulate the five-phase PMSM in the case of inter-tum short circuit fault helping to predict performances andor to extract fault signature in the machine main quantities. Simulation work has been carried out using MATLAB to verify the performance of the proposed detection/diagnosis method.

scholarly journals Linear Method for Diagnosis of Inter-Turn Short Circuits in 3-Phase Induction Motors

2019 ◽  
Vol 9 (22) ◽  
pp. 4822 ◽  
Author(s):  
Yeong-Jin Goh ◽  
On Kim
Keyword(s):  
Steady State ◽  
Induction Motor ◽  
Early Stage ◽  
Short Circuit ◽  
Linear Method ◽  
Linear Separation ◽  
Synchronous Reference Frame ◽  
Steady State Current ◽  
Diagnosis Method ◽  
Current Change

When a turn-to-turn short fault occurs in an induction motor, it will be accompanied by vibration and heating, which will have adverse effects on the entire power system. Thus, turn-to-turn short fault diagnosis of the stator is required, and major accidents can be prevented if an inter-turn short circuit (ITSC), which is the early stage of a turn-to-turn short, can be detected. This study reinterprets Park’s vector approach using Direct-Quadrature(D-Q) transformation for the linear separation of ITSCs and proposes an ITSC diagnosis method by defining the magnetic flux linkage pulsation and current change in the event of a turn-to-turn short. It is difficult to diagnose because the turn-to-turn short current change in an ITSC is considerably different from the induction motor loss. Hence, it was found through analysis that when the current change is considered through an analysis of the relationship between inductance and the winding number, the ITSC current becomes slightly smaller than the steady-state current. This was verified using the D-Q synchronous reference frame over time. We proposed a linear separation of the ITSC diagnosis from the steady state by considering the minimum values of the pulsating current as feature points.

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