H. H. Hanafy

Using 2D finite element analysis in the calculation of current and force distributions for induction motors with broken bars

In this paper an ABC transient model of the three phase induction motor is developed that depends on self and mutual inductances calculation based on accurate finite element analysis (FEA). This model can represent both healthy and faulty motor conditions. The rotor broken bars faults are studied thoroughly including their effects on the rotor bar currents distribution, the forces exerted on the rotor bars, the motor speed and motor torque. It was observed that broken bar faults will cause fluctuations in the motor speed and torque. It was found that the non-uniform distribution of the rotor bar currents will lead to non-uniform radial forces affecting the bars. This will increase the mechanical stresses on the rotor shaft.

Performance analysis of wound rotor induction motor subjected to rotor windings asymmetry

The aim of this paper is to analyze the performance of 3-phase wound rotor induction motor (WRIM) under rotor windings asymmetry. The behavior of WRIM were simulated under healthy and asymmetry conditions. With the aid of simulation results, variation of motor speed, electromagnetic torque, stator and rotor currents have been analyzed. To validate the simulation results a series of experiments were conducted for healthy and asymmetry rotor circuit. The results proved that for the asymmetry rotor windings conditions the stator and rotor current increase while the motor speed decrease and the ripples of speed and electromagnetic torque increase. The paper proved that the performance of the motor in the asymmetry rotor case is directly affected by the connection of rotor windings.

Low voltage ride-through technique for PMSG wind turbine systems using interval type-2 fuzzy logic control

This paper proposes a low voltage ride through (LVRT) scheme for the permanent magnet synchronous generator (PMSG) variable speed wind energy conversion system (WECS) at the grid faults to follow the requirements defined by the grid codes. The dc-link voltage is controlled by the machine-side converter instead of the grid-side converter. Taking into consideration the nonlinear relationship between the generator speed and the dc-link voltage, the machine-side converter controller is designed using interval type-2 fuzzy logic control (IT2-FLC). To validate the proposed control strategy, simulation results for 1.5-MW PMSG-based WECS are carried out by MATLAB-SIMULINK.

Analysis and force calculations for induction motors with broken bars using ABC frame model combined with 2D finite element method

In this paper, an ABC transient model of the three-phase induction motor is developed that depends on self and mutual inductance calculations based on accurate finite element analysis (FEA). This model can represent both healthy and faulty motor conditions. The rotor broken bars faults are studied thoroughly including their effects on the rotor bar currents distribution, the forces exerted on the rotor bars, the motor speed and motor torque. It was observed that broken bar faults will cause fluctuations in the motor speed and torque. It was found that the non-uniform distribution of the rotor bar currents will lead to non-uniform radial forces affecting the bars. This will increase the mechanical stresses on the rotor shaft.

A combined technique for rotor broken bar diagnosis in VSD equipped with vibration reducers

Broken rotor bar is a common fault in squirrel cage induction motors. Rotor failures due to that fault now account for a moderate percentage of total induction motor failures. This paper will deal with detection of broken rotor bar of induction motor supplied from variable speed drive (VSD) equipped with AC reactor and sine-wave shaping filter on the output side. The experimental results show that the instantaneous power spectrum analysis method is only effective when the motor is supplied from sinusoidal supply, in contrast for the demonstrated VSD. The instantaneous power spectrums of the healthy rotor case and the broken bar rotor cases is processed with mean absolute difference (MAD) approach algorithm to investigate the dissimilarity between them. The results show that this combined technique is highly effective in the diagnosis of broken rotor bar fault in case of the demonstrated VSD.

Steady state performance of a proposed connection for dual voltage operation of permanent capacitor motor

The purpose of this paper is to evaluate the steady state performance of a proposed connection of permanent capacitor motor (PCM) for dual voltage operation. The performance of the proposed connection is compared with the performance of the normal motor connection. The proposed connection has been tested using a dynamometer to experimentally verify the results of the theory and simulation results. Good agreement between the simulated and the experimental results has been obtained.