Ghaleb Hoblos

Impact of Pole and Slot Combination on Vibrations and Noise of Electromagnetic Origins in Permanent Magnet Synchronous Motors

In low- to medium-power-rated brushless machines, noise of electromagnetic origin is generally prevailing over mechanical and aerodynamic sources. The appropriate combination of pole and slot of a permanent magnet synchronous motor is one of the keys to its performances among which stands noise reduction. This paper investigates configurations regarding this aspect for distributed overlapping and single-layer concentrated nonoverlapping winding configurations. Chosen combinations are 8 poles 48 slots (8p48s), 8p72s, 46p48s and 50p48s. The air-gap flux density is obtained by 2-D finite element analysis (FEA), allowing to compute the electromagnetic pressure. It then serves as input of mechanical and acoustical 3-D FEA models of the stator with carter.

Power electronics interface configurations for hybrid energy storage in hybrid electric vehicles

This paper presents a study of different converter topologies used in the design of hybrid electric vehicle drive trains with emphasis on the power electronic interface for a battery/ultracapacitor hybrid energy storage pack. Each of the topologies proposed in literature has its own advantages and disadvantages, thus choosing an appropriate topology depends greatly on the specified application, design and operation requirements. Several aspects have to be considered to obtain a reliable comparison among different power converter topologies.

Modeling, design and fault analysis of bidirectional DC-DC converter for hybrid electric vehicles

This paper presents modeling, design and analysis of a bidirectional half-bridge DC/DC converter suitable for power electronic interface between the main energy storage system and the electric traction drive in hybrid electric vehicles. A hybrid energy storage system composed of a battery unit and an ultracapacitor pack is considered. A parallel dc-linked multi-input converter with a half-bridge bidirectional DC/DC cell topology is chosen to link the battery/ultracapacitor storage unit with the dc-link. The paper focuses on modeling the proposed converter for both dynamic and steady state analysis. Averaging and linearization techniques are applied to obtain the averaged state space models and small signal models of the converter in both boost and buck operation modes. A criterion for sizing the converter passive components based on the imposed design specifications and constraints is illustrated. Simulation results of the buck-boost converter during normal functioning and under faulty conditions are presented. In particular, short-circuit faults and open-circuit faults of diodes and transistors are analyzed.

Study on power converters used in hybrid vehicles with monitoring and diagnostics techniques

With the extensive use of power converters in modern hybrid vehicles, rises the need for efficient methods of condition monitoring and fault diagnosis to ensure the reliability of the automotive electrical power system. This paper is a technical review that studies power electronic devices and converters used in hybrid electric vehicles with a description of possible faults and a highlight on the recent progress of condition monitoring and fault diagnosis methods used in electric drive systems.

Impact of pole and slot combination on noise and vibrations of flux-switching PM machines

Flux-Switching machines (FSM) have been gaining attention during the last decade. Their electromagnetic behavior has been extensively studied for various topologies, i.e. U-core and E-core, simple (wound field or PM) and hybrid excitations FSM machines. Even though noise and vibrations of electromagnetic origins can be important drawbacks, depending on the application, only few studies are analyzing these aspects. As a result, this paper aims at understanding the sound power level of U-core flux-switching permanent magnet (FSPM) machines whose rotors have different number of poles. The stator of the extensively studied 12/10 stator/rotor pole FSPM machine (12s10rp) serves as a basis for investigating 12s11rp, 12s13rp and 12s14rp configurations. Electromagnetic pressure is calculated from the Maxwell stress tensor where the magnetic flux density is obtained with 2-D finite element analysis (FEA). It then serves as input of a mechanical and acoustical 3-D FEA model of the stator with carter.

Feature extraction for vibration-based fault detection in Permanent Magnet Synchronous Motors

This paper presents a study of different time and frequency indicators, extracted from vibration signals of a Permanent Magnet Synchronous Machine (PMSM), for fault detection and diagnosis purpose. First, a multi-physical model of the machine, able to generate the vibration displacement under different operating conditions, is simulated. Then, a brief state-of-the-art on the most encountered machine faults, with their electromagnetic and mechanical signatures, is presented. In this study, both rotor eccentricity and Permanent Magnet (PM) demagnetization faults are considered and introduced in the model by changing some of its parameters. After that, time- and frequency-domains signal processing techniques are applied to extract crucial features sets, related to healthy and faulty cases, from vibration signals. The evolution of these indicators with respect to faults degrees is analyzed to select proper criteria for each one, which can be effectively used latter in fault detection and diagnosis applications.

Piecewise switched Kalman filtering for sensor fault diagnosis in a DC/DC power converter

With the extensive use of power electronics in modern HEVs comes the need for efficient methods of condition monitoring and fault diagnosis to ensure the reliability of the electrical power system. This paper addresses sensor faults in a DC/DC power converter system interfacing the main energy storage unit and the AC drive in a hybrid electric vehicle. A residual-based fault diagnosis system that detects and localizes sensor faults in the examined system is designed. The proposed scheme extends the classic Kalman-based detection filter commonly used in linear time-invariant systems to a piecewise switched filter suitable for switched linear systems as those encountered in power electronics. Residuals of measured signals are generated by employing a bank of switched Kalman filters on a stochastic model of the converter. The generalized likelihood ratio test is then used as a statistical change detection method to evaluate the residuals and generate a detection function which is compared with a decision threshold to detect the occurrence of a sensor fault.

Decision on prognosis approaches of Hybrid Electric Vehicles' electrical machines

Hybrid Electric Vehicles (HEV) are becoming widely spread due to the predicted lack of fuel in addition to the pollution caused by the conventional vehicles. To overcome pollution and since it is expected that the lack of fuel will more increase, it is assessed that the production and use of HEVs will increase in the coming years. The main concern of HEVs is their reliability and availability; hence, assuring the health and proper operation of HEVs is a mission. Due to the importance of electrical machines health state in HEVs, this paper will present a survey on the available prognostic techniques that may be applied to assure an optimal and convenient operation of electrical machines in hybrid electric vehicle.

Multiphysical modeling for fault detection in Permanent Magnet Synchronous Motors

The aim of this paper is to present an analytical multiphysical model of Permanent Magnet Synchronous Motors (PMSMs) dedicated to fault detection purpose. The electromagnetic aspect is based on the analytical calculation of the Maxwell pressure in the air-gap. An existing mechanical approach is improved to compute natural frequencies of the machine taking into account its different parts. A better agreement has been obtained between analytical results and those issued from a Finite Element Analysis (FEA) applied to two different stator structures. The dynamic displacement signal of the stator is finally estimated in the space-time domain. Different operating modes of the machine can be simulated by changing some model parameters. In this paper, the rotor eccentricity fault is investigated and detected by the analysis of the vibration signal. Therefore, the proposed multiphysical model could provide healthy and faulty characteristics and could be suitably used for fault detection and diagnosis tasks.

Numerical versus analytical techniques for healthy and faulty surface permanent magnet machine

Hybrid electric vehicles are native revolution in the field of green and renewable energy. One of the important aspect of this system is the electric machine in the hybrid electric vehicle (HEV). The permanent magnet machine (PMM) being the most used in such application, this paper aim to model a small scale surface permanent magnet machine of power rate 7 kW. The modeling will be conducted using numerical (Finite Element Method) and analytical techniques where a comparison between the results generated by the two techniques will be presented. This will be done for two cases: once when the machine is at its health state and once when a crack occurs in the magnet. The paper will show the advantage of numerical method over the analytical method in terms of simplicity and accuracy.