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A dominant spatial airgap force order-based reference current profiling scheme is proposed in this work for noise, vibration and harshness (NVH) mitigation in Switched Reluctance Machines (SRM). The current profile optimization strategy is coupled with a fast vibration prediction method. Extensive simulations and experimentations are done on an 18 slot/12 pole SRM to verify the proposed strategy. Worst case noise scenario for the 18 slot/12 pole SRM is determined through experimental run-up test under constant torque condition. The proposed current shaping strategy is applied at the operating point experiencing worst case noise and significant NVH reduction is obtained through simulation and experimentation. Experimental results show a peak noise reduction of 14.24 dBA compared to a conventional square wave based current reference.

Noise, vibration, and harshness (NVH) in electric machines are mainly of electromagnetic and structural origin. This research focuses on isolating the structural and electromagnetic impacts on NVH performance, in a fractional slot concentrated winding (FSCW) permanent magnet synchronous machine (PMSM), brought by variation of different design parameters. A modification to the unit force response method is proposed for easier implementation in this work and is termed as lumped unit force response method. The modified method is experimentally verified before subsequent application for sensitivity analysis of various design parameters on NVH performance of a 12-slot/10-pole (12s10p) surface mounted PMSM. Separation of electromagnetic and structural impacts of different design parameters aids decision making during NVH performance optimization. Taguchi orthogonal array based mean and variance analysis are used during the sensitivity analysis in this work.

Phase current shaping is a common approach to reduce the radial force ripple and thus improve the noise, vibration, and harshness (NVH) performance of the switched reluctance machine (SRM). However, this method is reliant on the accuracy of the position and the current sensors. This paper presents an analytical approach to model the effect of position and current sensor errors on radial force ripple SRM and its impact on the NVH performance of the machine. As a phase current shaping method, current harmonics injection is chosen to analyze the sensor errors on its performance. Initially, the radial force is modelled using the Fourier series expansion. Then, position and current sensor errors in the SRM drive system are included in the analytical modelling. The harmonic orders of the radial force ripple are analyzed and simulated for different sensor errors. NVH performance of SRM is analyzed to show the effects of different sensor errors on the current profiling methods. Simulation and experimental results are provided to verify the proposed method of analysis.

This research focuses on wide speed range noise, vibration and harshness (NVH) performance comparison and optimization of different fractional slot concentrated winding permanent magnet synchronous machines (PMSM) for automotive application through a unit force response-based method of vibration prediction called vibration synthesis. Process verification is done for vibration synthesis through extensive testing of a 12 slot 10 pole (12s10p) PMSM before subsequent application for comparison of different PMSM designs. Most of the NVH comparison work available in the literature focus on single operating speed-based performance evaluation which is the drawback this work aims to remove. Different slot/pole combinations of PMSMs are compared in this work in regard to their NVH performances. Electromagnetic and/or mechanical impacts brought by one structural NVH performance improvement method is analyzed in detail using unit force response method, and subsequently, vibration synthesis is used to compare the NVH performances over the entire speed range of interest. This will offer a better understanding of different design modifications done for NVH performance improvement in electric machines.

Apart from performance requirements like efficiency and thermal stability of electrical drives, NVH-criteria (noise vibration harshness) such as low acoustic noise emissions and vibrations are very important in vehicle applications. In this study, we present a method to reduce a 3D structural model with boundary conditions which consider the mounting of the machine and combine it with a 2D-FEA analysis to determine the spatial force harmonics. In addition, the zero-sequence currents of delta-connected machine are considered and their impact on the forces is discussed. Moreover, the simulation results are compared to experimental data. Through the boundary conditions of the 3D-modal analysis, torsional mode shapes are regarded for the first time in a not strictly FEM-based approach. As this process is a multi-physics approach, each step starting with the electromagnetic force calculation, the 3D-modal analysis and the analytical surface deflection calculation is introduced and explained.

Summary & ConclusionsThe development of an engine-cooling module (ECM) for an European carmaker faced a major blocking point. The stalemate concerned the design of the suspension rubbers separating the engine-cooling radiator (the ECM carrier) from the chassis. The development of an engine-cooling module (ECM) for an European carmaker faced a major blocking point. The stalemate concerned the design of the suspension rubbers separating the engine-cooling radiator (the ECM carrier) from the chassis. From the one hand, the damping rubbers had to be soft, in order to be compliant with noise, vibration & harshness (NVH) criteria – acoustic noise and vibration transmitted to the cabin. On the other hand, their softness would provoke such high amplitude response during shaker tests that the module carrier (the radiator) would fail at the early stage of vibration testing – a leakage was observed after 10 hours of the targeted 90 hours duration. New rubbers, designed for durability purposes, would fail to meet the NVH criteria. The project development team went through a double-faced dilemma: how to design rubbers with an acceptable trade-off between NVH and durability of the engine-cooling radiator, and how to find a quick and efficient way to validate the design in order to be compliant with vibration validation tests. Together with the customer, our company (automotive tier-1 supplier) established an iterative design optimization of the damping rubbers, based on the simultaneous feedback from the acoustic response and the durability predictions. The goal was to develop a strategy permitting a quick an effective criteria for damage estimation for each design proposed.

Machine learning algorithms are nothing but programs in computes that try to forecast the decisions based on data driven assignment. In diagnosis of cancer the goal is to trained algorithm of machine learning that awards the appearance levels from cancer patient, can precisely predict what type and harshness of cancer they have. Breast cancer is the most delicate and deadly among all of the diseases in medicine. In this paper breast cancer classification is implemented using Find-S and Candidate elimination algorithm. These algorithms are used for the breast cancer detection. Navie Bayes Classifier is used for classification of breast cancer.

Since permanent magnet synchronous motor (PMSM) is the key component of electric vehicle (EV) propulsion system, the noise, vibration and harshness (NVH) behavior of PMSMs is essential to the riding amenity of EVs. The noise performances of PMSMs are mainly caused by the electromagnetic forces and can be amplified by the mechanical structure. Therefore, in this paper, the electromagnetic forces are comprehensively studied in terms of time and spatial harmonic distributions with the employment of 2D finite element analysis (FEA) and Fourier transformation (FFT) under different operating conditions. Then, in order to improve the noise performance, an optimal design of the rotor is proposed to minimize the radial electromagnetic force. Finally, the effectiveness of the optimal rotor design is verified by both anechoic chamber test and real vehicle test.

The automobile industry is actively developing hybrid electric vehicle (HEV) or electric vehicle (EV) with electric motors to overcome the limitations of conventional internal combustion engine cars. This has the advantage of significantly improving the fuel economy of existing internal combustion engine cars, but it can be annoying to the driver by creating a whine noise in the new frequency range. This paper proposed a new design concept based on the electromagnetic shape optimization to improve the noise, vibration and harshness (NVH) performance. The new design was optimized using the response surface methodology (RSM). As a result, NVH have been improved dramatically as well as the motor efficiency with the virtual slot technology. The motor was prototyped and confirms the cogging torque reduction. Moreover, the whine noise level was satisfied beyond the goal. The design has been patented to obtain the technical excellence.

Traffic accidents can affect sufferers in several ways, from light physical wounds to mortality. Even, in some areas, an accident could also cause significant material goods cost. Instantaneous rescue is critical because the harshness of those undesirable properties extremely be determined by how fast police or officer of other related institutions know, react and reach the location of the accident. In this study, a system is built to detect, find location and identify the shortest path to reach the location of an accident. There are three main parts of the system, including an accelerometer, GPS receiver and a GPRS module which are connected to a microcontroller, a program in a web srver implementing K-Nearest Neighbor to search for the shortest path from a police station to the location of accidents, and a program installed in the police stations to show the shortest path in a form of a map. By implementing this system, response time to a traffic accident is potentially reduced and the fatality of injuries is decreased.

Automotive air conditioning compressor bracket connects the compressor and engine, and make its long-term vibration in the bad environment, which will cause the compressor can't work smoothly, safely and reliably, therefore the design rationality of automotive air conditioning compressor bracket, directly affects the performance of air conditioning, in turn, affects the vehicle harshness (NVH) performance. So analyze the vibration performance of air conditioner compressor in the design phase is particularly important. This article analyzed the modal of the air conditioning compressor bracket based on the finite element method, and carried out the structure optimization for the bracket, and finally anticipated effect has realized for the mode improve.

This paper presents a critical review of control strategies for switched reluctance motor employed in electric vehicle. The survey is carried out on various control strategies namely average torque control, instantaneous torque, torque sharing and direct instantaneous torque control. The purpose of the survey is to identify the capability of control strategies in terms of speed and torque of SRM for electric vehicle application. The preliminary observation from the study is that, SRM have high torque ripples and it is severe during commutation between the adjacent phases. Further, it also leads to high acoustic noise, vibration and harshness of the electric vehicle system. In view of this, there is need to develop an appropriate control method to overcome the said problems of SRM drive employed in EVs.

In the highly competitive global automotive market and with the taste of customer becoming more refined, the need to develop high quality products and achieve product excellence in all areas to obtain market leadership is critical. Buzz, squeak and rattle (BSR) is the automotive industry term for the audible engineering challenges faced by all vehicle and component engineers. Minimizing BSR is of paramount importance when designing vehicle components and whole vehicle assemblies. Focus on BSR issues for an automobile interior component design have rapidly increased due to customer's expectation for high quality vehicles. Also, due to advances in the reduction of vehicle interior and exterior noise, engine mounts have recently been brought to the forefront to meet the vehicle interior sound level targets. Engine mounts serve two principal functions in a vehicle, vibration isolation and engine support. The objective of this paper to experimentally analyze the impact of conventional engine mount design on the rattle and whistling noise audible from the engine mounts when the vehicle is subjected to rough road conditions and pot holes at slow speeds. The test methodology demonstrates how to simulate and co-relate the actual vehicle level noise on a BSR 4 poster test rig. A design change is proposed to abate the rattle noise from engine mounts considering the numerous variables involved and without affecting the critical NVH (Noise, Vibration and Harshness) and durability performance parameters. The level of noise reduction achieved is quantified through the substantial reduction in BSR demerit score which in turn reflects the improvement in perceived quality of the vehicle, increased customer satisfaction index and improved JD power (JDP) ratings

With the development of electric vehicles, more and more attentions have been put on understanding and attenuating the noise, vibration, and harshness (NVH) of traction machines. NVH in machines are mainly caused by the electromagnetic force, which is complex vector functions of both time and space, and models are desired for accurately evaluating its characteristics. In this paper, analytical models for estimating the air gap flux density and electromagnetic force in interior permanent magnet synchronous machine (IPMSM) with distributed windings are established. The effects of stator slots and rotor saliency are taken into consideration to ensure the validity of the model. Temporal and spatial harmonic distributions of electromagnetic force are studied separately. The electromagnetic force of a 44 kW 8-pole/48-slot IPMSM is evaluated using 2-D finite element analysis (FEA) and 2-D fast Fourier transformation (FFT) method. The simulation results agree well with that predicted from the analytical model. The relationship between mode numbers and temporal harmonics is identified. In addition, it is found that tooth harmonics and rotor harmonics have strong influences on the amplitude of electromagnetic force.

This work addresses an efficient and highly reliable Noise-Vibration-Harshness simulation and analysis framework for electrical induction drives in E-mobility applications. Based on a combined nonlinear analytic and Finite-Element modeling structure in spatial frequency space the entire operational Noise-Vibration-Harshness-simulation is embedded in one simulation environment and can be performed with high richness of detail in comparison to usual simulation approaches. By using modal and Fourier-based decompositions of physical quantities the operation point dependent behavior is described by order-reduced order models. This allows an effective connection to various E-drive and control topologies to simulate the Noise-Vibration-Harshness-behavior for arbitrary operation cycles efficiently. The modeling approach is applied to a squirrel-cage three-phase induction machine. Simulation results as acoustic run-up spectrograms are shown and operational deflections at critical speeds are visualized. Electromagnetic and structural mechanic individual noise contributions are extracted as well as correlations between physical domains are derived. The high reliability of the simulation results is proven by a good correlation to real world measurements.

One of the primary advantages of electric vehicle (EV) is to easily incorporate a regenerative braking system where the lost KE during braking is restored into the vehicle energy storage. But, due to limited energy storage, inadequate charging station and long charging time, the braking energy regeneration is required to be maximized to enhance the EV range. Since driving harshness has a great influence on the regeneration efficiency, an optimal driving strategy during deceleration of an EV is determined here by solving a multi-objective optimization problem (MOOP). The MOOP is solved based on three primary conflicting objectives, namely minimization of deceleration duration, maximization of regenerative braking energy and minimization of jerk. Optimization results are presented for a representative speed change in different driving cycles. After analysing the Pareto-fronts, a zone of optimal driving is identified. During deceleration, driver selects a solution (driving strategy) from the zone based on higher level information such as safe distance to avoid accident, etc.

As government regulations force stringent automobile emission standards with graceful degradation under various hardware faults and operating environments, accurate feedback control of the engine air-to-fuel ratio has become a key enabler. We present an overview of the automotive three-way catalyst (TWC) control system and discuss challenges associated with development and implementation of a successful feedback controller, including plant and sensor nonlinearities - in use, as well as regulatory On-Board-Diagnostics induced faults, bandwidth restrictions, and constraints such as drivability and noise, vibration, and harshness (NVH) considerations. To meet these goals, we modify the conventional mid-ranging control structure for accurate control of the TWC subsystem while simultaneously adhering to drivability and NVH constraints. Vehicle test results are shown exhibiting the controller's capabilities with and without induced faults.

To improve the fuel economy and range of an electric vehicle, as much as energy regeneration during braking is important. It was observed that driving harshness has a great impact on the regeneration efficiency during vehicle deceleration. On the other hand, to reduce the trip time as well as to avoid accident, the deceleration duration needs to be kept short. By realizing these conflicting objectives, in the present work an optimal deceleration is find out for a speed change using a genetic algorithm. The concerned multi-objective optimization problem (MOOP) was solved based on two approaches: considering a constant deceleration, and variable decelerations during braking. Comparative results of both the approaches are presented for a representative speed change in four driving cycles. Results of both approaches in solving the MOOP including under certain constraints, such as a desired comfort journey and maintaining a safe braking distance, suggest that multiple decelerations should be used during planned braking, where as either a constant or multiple deceleration may be taken during braking for high comfort journey and under emergency braking demand.

This paper presents a comparison of soft and hard chopping on an 8/6 SRM in terms of noise, vibration and harshness. Transient-state measurements are used to plot speed-frequency signatures of current, vibration and acoustic noise of the SRM for different load torques. With this technique speed-related frequencies can be distinguished from resonance frequencies, and therefore, more information can be extracted from the plots. The results show that hard chopping increases the loudness of acoustic noise compared to soft chopping, with a frequency shift to higher values. This however leads to an attenuation of the vibration and noise amplitudes at the most critical resonance of the SRM, situated at a relatively low frequency., info:eu-repo/semantics/published

Fractional Slot Concentrated Winding (FSCW) Interior Permanent Magnet (IPM) synchronous motors are nowadays an attractive solution in automotive applications due to their important advantages in terms of high performance and manufacturing simplicity. Among the different topologies, the spoke type is an effective configuration when high torque density is required. On the other hand, the motor performance are heavily related to the selected slot-pole combination. This is a critical issue when there are high constraints in terms of torque quality, flux weakening performance and noise/vibration/harshness. This paper deals with the design and analysis of FSCW IPM spoke type motors, comparing eight optimal slot-pole combinations. Two different low cost PM typologies are considered. Design and optimization procedures, based upon a finite element analysis, are presented. The torque density, torque quality, electromechanical performance and deformation of the machines are compared, highlighting the advantages and the differences among the solutions.

In underwater wireless communication networks, a large number of nodes are deployed in different forms to cover small or large areas of interest for various practical applications. The proper accomplishment of those applications depends on the number of active nodes at any time of instant. But due to the harshness of underwater environment such as high absorption, reflections, refractions, dispersion, the number of active node can vary over time. However, node estimation has become difficult using existing terrestrial protocols. A technique was performed for node estimation considering equal receive power of the signals where the receivers receive equal amount of power. But sometimes it becomes hard to achieve equal receive power at receivers due to the distance-dependent attenuations. So we propose a node estimation technique considering the effect of dispersion coefficient which is the main factor of the distance-dependent attenuation. In this method, we will consider White Gaussian signal as transmitted signal where all the transmitted signals from the nodes will be considered as of equal strength.

Due to the harshness of underwater environment, size estimation of underwater network is difficult using conventional protocol techniques. A statistical signal processing approach of size estimation is proposed for this purpose using cross-correlation of Gaussian signals, which is effective for any environment networks. Limited bandwidth of underwater communications channel poses constraint on using Gaussian signal, which has infinite bandwidth. The aim of this paper is to investigate the effect of this limited bandwidth in cross-correlation based underwater network size estimation using Gaussian signals with finite bandwidth.

Designing new communication protocols on the powerline network requires knowledge of the nature of the channel and the error pattern on real scenarios. This paper presents 3 main outcomes: (i) a simplified methodology for fast characterization of the narrowband powerline channel on scenarios with varying degrees of harshness, without requiring the use of expensive hardware equipment and not strictly defined measurement boundary conditions. (ii) A detailed analysis of the obtained results using the proposed methodology, comparing the results with those obtained using other more complex methods, and a study of the Self-Similar characteristic of the error sequence. (iii) On the basis of the measurements obtained for different scenarios, we propose a simplified narrowband PLC channel model for generating realistic error patterns in discrete event simulation environments.

Commercial off the shelf processors are becoming mandatory in space applications to satisfy the ever-growing demand for on-board computing power. As a result, architecture able to withstand the harshness of the space environment are needed to cope with the errors that may affect such processors, which are not specifically designed for being used in space. Beside design and implementation costs, validation of the obtained architecture is a very cost- and time-consuming operation. In this paper we propose an architecture to quickly develop dependable embedded systems using time redundancy. The main novelty of the approach lies in the usage of a hyper visor for implementing seamlessly time redundancy, consistency checking, temporal and spatial segregation of programs that are needed to guarantee a safe execution of the application software. The proposed architecture needs to be validated only once then, provided that the same hyper visor is available for different hardware platforms, it can be deployed without the need for re-validation. We describe a prototypical implementation of the approach and we provide experimental data that assess the effectiveness of the approach.

This paper introduces unusual vibration and noise test of the transmission in NVH road testing system. It analyses test data in detail by using dynamic signal analysis software. By analysis, we know that the vibration signal and noise signal measured in road testing system exactly match the actual vibration and noise signal of the transmission, which shows that it is feasible to carry on vibration and noise test (NVH test) in this system.

NVH (noise, vibration and harshness) characteristics of modern vehicle are becoming more and more serious especially large power diesel engine. Various isolators are designed for engines as their mount systems’ isolation components. The study used two kinds of different isolator such as rubber isolator and metal-net isolator as a large power diesel engine's mount. Study and experiments were made. The static test showed that metal-net isolator has larger damping and can suppress impulse and resonance vibration effectively. The engine’s frame vibration comparison tests were also made on their control efficiency and vibration transfer rate. The signals were processed by means of MATLAB. The results indicated that the vibration transfer rate of the metal-net isolator is lower than that of the rubber isolator. The metal-net isolator has advantages over rubber isolator and can be used as diesel engine's mount component .

The simulation method to design car interior trims based on NVH performance is introduced in this paper. An SEA (statistical energy analysis) model with all the parameters was built based on a domestic car. The inputs of interior noise were got by the combination method of roads testing and other simulations. The sound pressure levels in the engine bay and at driver?s ear in some running conditions were measured. And the inputs to auto-body from engine mounts were also measured. The aerodynamic pressure and suspensions inputs to panels in high speed were simulated. The accuracy of this model was validated by the results of software. Then, the simulation expressed that the interior high noise of a car can be reduced by adding the sound insulation and absorption in interior trims design. The research of this paper covered all the effects of aerodynamics, engine inputs and the suspensions inputs together. The interior trims design is very significant to improve the NVH (noise vibration & harshness) performance using SEA simulation. And the research of this paper can be used to direct the application of trims materials in car interior trims design.

Throttle holes area of telescopic shock absorber influence the ride comfort, driving harshness and the other parameters design. For the non-linearity relation of the design area of throttle holes with the design velocity, there is no any accurate and reliable method for throttle hole area design of telescopic shock absorber. In this paper, analyzed the various damping factors affecting design, it was established that the mathematics model of throttle hole area by single velocity value. Studied the method of optimization design, the target function of curve fitting optimization design for throttle hole was constructed. A practical design example of throttle holes area with this method is given, and the designed result was compared with that by single velocity, and shown on the blueprint of telescopic shock absorber manufactory. The performance test was conducted for the telescopic shock absorber developed with the new design methods in laboratory, and the test results were compared with the design target value. The experiment results show that the design method of curve fitting optimization for the area of throttle hole is correct, the designed values is reliable.

Under the excitation of the engine and road surface, the vibration energy of the exhaust system which will result in the vibration of the body and produce the structure noise transfers to the body from the hanger. This will seriously affect the noise, vibration and harshness (NVH) performance of the vehicle. Average driving degree of freedom (DOF) displacement (ADDOFD) is applied to select hanger locations of the automotive exhaust system in this paper. The numerical model of the normal modal analysis of the exhaust system has been studied; several numerical models have been analyzed with the test correlation technology; and the accurate numerical model has been found. Exhaust systempsilas free-free mode and sum of its eigenvectors are offered using MSC.Nastran. Hanger locations are recommended at the position where the ADDOFD is relatively lower. Then static analysis and dynamic analysis of the exhaust system are done, and finally hanger locations of the exhaust system are selected. When the reasonable hanger positions have been decided, the vibration level of the body and the internal noise would have been decreased. This method can effectively select better NVH performance hanger locations in the earlier vehicle development process.

The throttle holes area of telescope damper influence the vehicle ride comfort, driving harshness and other parameters design. As the no-linearity relation between the design area of throttle holes and design velocity, there is no any accurate and reliable method for throttle holes area design. The paper analyzed various damping components which impact the design and established the mathematics model of throttle holes area based on single velocity, studied the optimum design methods and established the target function of curve fitting optimization for throttle holes area. A practical design example with the new method was given, and compared the design result with that by single velocity and that of the blueprint of factory. The performance test was conducted in laboratory, and compared the test results with the design target values. The experiment results show that the curve fitting optimization design method for the area of throttle holes is correct, the designed value is reliable, and it has important reference value for valves parameters design of telescope damper.

We introduce the - strikes-out algorithm, a simple steady-state genetic algorithm for competitive coevolution. The algorithm can be summarised as follows: Run competitions between randomly chosen individuals, keep track of the number of defeats for each individual, and remove any individual which has been defeated times. Naive application of the algorithm in 2-population problems leads to severe disengagement. We find that disengagement can be eliminated (for all tasks involving real-valued continuous scores) by determining ‘ victories’ and ‘ defeats’ between fellow members of the same species, using competitions against a single member of the opposing species as a point of comparison. We apply our algorithm to the “ box-grabbing” problem for artificial 3D creatures introduced by Sims. We compare our algorithm with Sims’ original Last Elite Opponent algorithm, and describe (and explain) different results obtained with two different implementations differing mainly by the harshness of their selection regimes.

Despite the efforts of highly qualified engineers, designers and technicians; many motor driven devices have unacceptable levels of noise, vibration and harshness. This paper is applicable to large industrial exhaust fans, domestic vacuum cleaners, industrial pumps and compressors, and a host of other applications.

The ever increasing demands regarding reduction of noise, vibration and harshness (NVH) of machinery, power tools, household devices and rotating components in automotive applications require improved balancing accuracy and reduced balancing tolerances, among other manufacturing and design criteria, like reduction of audible bearing noise or air borne noise. This is true for rotors in various industrial applications like turbo machinery, and especially important for small armature electric motors, used in automotive applications. NVH requirements in the automotive industry are pushing the limits of technology. In recognising this need, we realized new technology and new techniques needed to be developed.

When buying a new induction motor, the purchaser must decide on what amount and type of testing needs to be conducted to be assured that the motor will perform as required for their application. Various tests are available to verify performance and integrity, and the value of these tests depends on the application, user's experiences, motor size/voltage, etc. Many of these tests are not standard, and may add to the motor cost without adding significant value to the purchaser. Furthermore, while some of these tests may help ascertain a motor's reliability and performance, the testing may be harsh on the motor, degrading the integrity of the motor in the process. By determining which tests are truly required, both from a cost and a harshness perspective, an optimized motor test can be purchased. Also, alternate test procedures may exist which may yield similar information, but without the stress imposed by more traditional test methods and/or specifications. This paper explores the various tests available for induction motors, along with an analysis of the stress on the motor and value of information derived.

When new motors are purchased, various tests are conducted to verify their performance and integrity. Many of these tests are not standard, and may add to the motor cost without adding significant value to the purchaser. Furthermore, while some of these tests may help ascertain a motor's reliability and performance, the testing may be harsh on the motor, degrading the integrity of the motor in the process. The value of the tests depends on the application, users experiences, motor size/voltage, etc. By determining which tests are truly required, both from a cost and a harshness perspective, an optimized motor test can be purchased. Additionally, alternate test procedures may exist which may yield similar information, but without the stress imposed by more traditional test methods/specifications. This paper explores the tests available for various induction motors along with an analysis of the stress on the motor and value of information derived.

The paper describes a new signal processing technique for understanding the dynamics of time-varying signals in vehicles: hyperstate analysis. Vehicle noise and vibration are examples of randomly-varying transient or non-stationary signals that are not effectively analyzed with classical spectral analysis techniques. By the use of nested hidden Markov models, hyperstate analysis explicitly identifies transient and nonstationary behavior on many time scales for better signal discrimination. It uses a probability-based framework that allows for automated, objective classification of noisy signals. The technique is applied to engine starting sequences from different types of vehicles. This work demonstrates that hyperstate analysis discerns similarities and differences in randomly-varying signals of this type, and can perform effective automatic, objective classification and signal decomposition for NVH (noise, vibration, and harshness) studies.

Modeling of automotive Permanent Magnet Synchronous Machines (PMSM) electric drives for Noise, Vibration and Harshness (NVH) assessment involves modeling different components such as electrical machine, power electronics and controller. The usage of transistors for machine control affects the NVH performance, especially within the switching frequency range. Traditionally the method to include power electronics models is to use co-simulation to couple a circuit simulator with an electromagnetic Finite Element (FE) model. However, this approach is computationally expensive. To overcome this limitation, the electromagnetic behavior of the machine can be approximated by using reduced order models. This work compares the co-simulation approach with the system-level model in terms of high frequency NHV behavior. The comparison provides results in terms of time and accuracy.