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Detection of broken bars in frequency converter fed induction motor using Park's vector approach
Abstract
This paper presents the experimental study of induction motor broken rotor bars diagnostics. Fault tests are performed on a machine with 3 broken bars, driven through a frequency converter. Park's vector approach is used as an analyzing tool to detect the broken rotor bars. Park's vector patterns in case of stator current and voltage are investigated. Results of the tests and discussion are presented. Necessity for further study is pointed out.
... Additionally, the inherent nonlinearities introduced by the PWM control strategy can affect the accuracy of fault detection algorithms designed for linear systems. Moreover, the inverter operation can mask or distort faultrelated characteristics in the motor's electrical and mechanical responses, making it difficult to fault identification [9]- [11]. Therefore, carefully considering and developing specialized fault diagnostics techniques are necessary to monitor and diagnose faults in PWM-based inverter-fed induction motors effectively. ...
... This situation will generate significant financial loss and should be avoided to the maximum extent. Hence, early detection of faults with appropriate condition monitoring and diagnostic techniques within the motor is always required in terms of all means of time and money [1][2][3]. ...
Due to their efficiency and control capabilities, induction motors fed with inverters have become prevalent in various industrial applications. However, ensuring the reliable operation of the motor and diagnosing faults on time are crucial for preventing unexpected failures and minimizing downtime. This paper systematically analyzes condition monitoring and practical diagnostic techniques for inverter-fed motor drive systems. This study encompasses a thorough evaluation of different methods used for condition monitoring and diagnostics of induction motors, with the most crucial faults in their stator, rotor, bearings, eccentricity, shaft currents, and partial discharges. It also includes an assessment of their applicability. The presented analysis includes a focus on the challenges associated with inverter-fed systems, such as high-frequency harmonics, common-mode voltages causing the bearing currents, and high voltage gradients (dv/dt) due to fast switching frequency, which can impact the motor operation, as well as its faults analysis. Furthermore, this research explores the usefulness and efficiency of various available diagnostic methods, such as motor current signature analysis and other useful analyses using advanced signal processing techniques. This study aims to present findings that provide valuable insights for developing comprehensive condition monitoring strategies, and practical diagnostic techniques that enable proactive maintenance, enhanced system performance, and improved operational reliability of inverter-fed motor drive systems.
... Although, on the basis of the calculated main electromagnetic harmonics, this effect is rather weak. At the same time, the other studies show that, detection of broken rotor bars of SCIM could be done by using Park's vector approach [2], that means it is possible to improve one-phase EEC by providing a proper reference frame transformation. ...
... The world today is moving towards smart grids and distributed electricity generation. This is a challenge for traditionally centralized systems, because instead of the big generation units, many smaller units distributed all around the system are starting to emerge (Vaimann et al., 2012). On the other hand, wider usage of renewable energy sources and efficient use of electricity can be the way to solve most of the problems in electricity generation today. ...
The paper analyzes the reasonability of using an off-grid hybrid power supply system or in other words a local grid for sparsely populated areas as well as the necessary components selection and price development of such system. Typical consumers are selected and all estimations and calculations are based on them. Consumer profiles are set and analyzed as well as different elements of the local power supply grid and the possibility of connecting to the traditional grid. Estonian example is used in this paper as the country lies relatively north and has some remote areas, where local power supply grids can be implemented. All prices in the paper are derived from the Estonian example. Necessity of further study is proposed.
... The world today is moving towards smart grids and distributed electricity generation. This is a challenge for traditionally centralized systems, because instead of the big generation units, many smaller units distributed all around the system are starting to emerge [1]. On the other hand wider usage of renewable energy sources and efficient use of electricity can be the way to solve most of the problems in electricity generation today. ...
This paper analyses the reasonability of using an offgrid hybrid power supply system or a local grid for sparsely populated areas. Two typical consumers are selected and all estimations and calculations are based on the two. Consumer profiles are set and analyzed as well as different elements of the local power supply grid and the possibility
of connecting to the traditional grid. Estonian example is used in this paper as the country lies relatively north and has some remote areas, where local power supply grids can be implemented. All prices in the paper are derived from the Estonian example. Necessity of further study is proposed.
The Park’s Vector Approach (PVA), together with its variations, has been one of the most widespread diagnostic methods for electrical machines and drives. Regarding the broken rotor bars fault diagnosis in induction motors, the common practice is to rely on the width increase of the Park’s Vector (PV) ring and then apply some more sophisticated signal processing methods. It is shown in this paper that this method can be unreliable and is strongly dependent on the magnetic poles and rotor slot numbers. To overcome this constraint, the novel Filtered Park’s/Extended Park’s Vector Approach (FPVA/FEPVA) is introduced. The investigation is carried out with FEM simulations and experimental testing. The results prove to satisfyingly coincide, whereas the proposed advanced FPVA method is desirably reliable.
This paper presents the experimental study of three-phase squirrel cage induction motor broken rotor bars diagnostics. Tests have been performed with two different machines, one through a frequency converter and the other supplied directly from grid. This comparison has been presented, as the use of frequency converters changes the traditional current spectrum of the machine and hence the diagnostic of such machines
becomes more difficult. Necessity for further study on the behavior of the frequency converter in the weak grid is pointed out.
This paper presents the experimental study of induction generator broken rotor bars diagnostics. As induction generators are often used in renewable energy applications,
such as wind and hydro power plants where they are also equipped with frequency converters, diagnostics of such machines is becoming more important. Tests are performed with an induction machine with a healthy rotor and a rotor with three broken bars, supplied through a frequency converter. Park’s vector approach is used as an analyzing tool to detect the broken rotor bars. Park’s vector pattern using stator current and voltage is investigated. Results of the tests and discussion of the results are presented. The necessity for further study is pointed out.
During the past few decades there has been a continually increasing interest and investigation into fault detection and diagnostics of induction motors. There are various
different diagnostic approaches and methods to detect faults in induction motors. Attention should be paid to the fact that as induction motors are often used in critical duty drives, it is essential not to disturb the working cycle of the motor in any way while performing the needed diagnostic procedures. The needed measurements have to be carried out with the motor remaining in its normal operating mode, as changing of the working cycle can mean safety risks and economic losses in some applications where induction motors are used. This paper gives an overview of the sensorless diagnostic possibilities of three-phase squirrel-cage induction motors with broken rotor bars via the analysis of stator current.
Due to their rugged build, simplicity and cost effective performance,
induction motors are used in a vast number of industries, where they
play a significant role in responsible operations, where faults and
downtimes are either not desirable or even unthinkable. As different
faults can affect the performance of the induction motors, among them
broken rotor bars, it is important to have a certain condition
monitoring or diagnostic system that is guarding the state of the motor.
This paper deals with induction motor broken rotor bars detection, using
Clarke vector approach.
Induction motors have nowadays been more frequently used with frequency converters. The use of frequency converters affects the behavior of the machine and makes fault diagnosis more complicated. One of the widely used diagnostic methods is motor current signature analysis (MCSA). This method is based on measurement of sidebands in the stator current spectrum. Those sidebands are usually located close to the main supply frequency. Frequency converter causes supply frequency to slightly vary in time and, as a result, some additional harmonics in the current spectrum are induced and sidebands are reduced. Those harmonics can be easily misinterpreted as the sidebands caused by the rotor faults. Although the rotor faults in the case of frequency converter supply are not so often, precaution is still necessary. In this paper the experimental results of fault diagnosis carried out using standard supply and using frequency converter have been compared and presented. All tests were performed on 22 kW, 380 V, 1470 r/min induction motor. The current spectra are given for the motor with two broken bars with both types of supply.
Induction Machines in the Industry. Topology and Operation of Induction Machines Materials and Losses. Windings and their mmfs. No-Load Field Distribution. Equivalent Circuit Parameters. Steady-State Performance Calculations. On-Load Saturation and Frequency Effects on Circuit Parameters. Skewing and Inter-Bar Rotor Currents. Space Harmonics in Airgap Field. Core and Winding Fundamental and Harmonic Losses. Thermal Modeling. Space Phasor Models for Transients and Variable-Speed Operation. Design Specifications. Preoptimization Design Methods and Case Studies. Design Optimization Methods. Design Optimization Case Studies for Constant Frequency Operation. Design Optimization Case Studies for Variable Frequency Variable Speed Operation. Design of Induction Generators. Design of High-Speed Induction Motors Linear Induction Motors. Ultra-High Frequency Effects of Power Electronics Tests on Induction Machines. Induction Motor Monitoring. Single-Phase Induction Motors.
The subject of online detection of airgap eccentricity in
three-phase induction motors is discussed, and a noninvasive approach,
based on the computer-aided monitoring of the stator current Park's
vector, is introduced. Experimental results, obtained by using a special
fault producing test rig, demonstrate the effectiveness of the proposed
technique, for detecting the presence of airgap eccentricity in
operating three-phase induction machines