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This paper presents a novel control strategy to significantly reduce the high-frequency transformer loss in a modular solid-state transformer (SST) based converter system. The modular SST design is based on an ac–dc power-electronic building block comprised of an H-bridge at the ac input and a bidirectional soft-switching isolated dc–dc converter with a medium-voltage insulated high-frequency transformer. The ac terminals of input H-bridges are connected in series and directly coupled to the medium-voltage ac line, while the output dc terminals are all connected in parallel at a low voltage. The key innovation described in this paper, without sacrificing the output performance, is the control scheme that reduces core and winding losses associated with the dc–dc resonant stage by turning off the selected dc–dc converters in synchronism with the line voltage. The prototype for the test described in this paper is based on a modular SST where each module is rated at 50 kVA, with a 200 kHz transformer using 1.7 kV silicon carbide discrete mosfets, but the described control concepts are more broadly applicable to similar topologies. [ABSTRACT FROM AUTHOR]

This paper presents an in-run mode-matching method for MEMS gyroscopes based on the power symmetry between the sideband signals in the sense mode. The method takes advantage of the power symmetry of both the noise and the Coriolis response within the upper sideband (USB) and the lower sideband (LSB) of the driving frequency. The power difference is taken as a mismatch detection and is fed to the mode-matching controller, which regulates the tuning electrodes. During the matching control, the history of the estimated mode order is recorded to adaptively tune the controller gain, speeding up the tracking process and reducing the steady ripples. The experiments exhibited that the frequency loop could converge to the steady-state within a reasonable time and with 0.28Hz peak-peak fluctuation. By the mode-matching, the scale factor of the gyroscope under test was boosted by ten times; the angle random walk was enhanced from 8.13deg/h/sqrt(Hz) to 1.99deg/h/sqrt(Hz); the bias instability was improved from 2.09deg/h to 1.12deg/h. The method proposed in this paper can be implemented with a general platform that MEMS gyroscopes usually utilize. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) are emerging as an alternative transportation system owing to a reduction in depleting lubricates usage and greenhouse gas emissions. This paper presents a technical review of each and every sub-system and its feasible control of battery EV (BEV) propulsion units. The study includes the possible combination of electrical machines (EMs), storage system, and power electronic converters and their associated control strategies. The primary unit, i.e., EM, is the heart of the EV, which is used to drive the vehicle at the desired speed as well as to restore the regenerative braking (RB) energy that is generated to enhance the overall system reliability. To electrify the transportation sector, it is necessary to include new options of power electronic converter topologies and their associated control strategies for numerous reasons, which include extracting maximum power from sources in case the EV is powered from renewable energy resources, boosting the energy storage capability for longer electric range, managing power flow from the source to battery or battery to vehicle or vehicle to battery, and regulating the speed of the vehicle and braking control. Based on the survey, the suitable combination of sub-systems and their control for three and four-wheeler EVs are summarized in this paper. [ABSTRACT FROM AUTHOR]

From many years in order to maximize the working productivity of the industrial equipment, the control and data acquisition systems have always been available for modernized industrial architecture. However, to increase the reliability of the plant/process, these systems have always tended to be expensive on small and medium scale purposes. Similarly, electric drives find many applications in industries as well as household purposes. Also, for a greater productivity of electric drives, control becomes necessary and will always benefit the end user. This paper presents a microcontrollerbased control and data acquisition system for electric DC drives that is low cost, modular, and can be installed in stages determined by budget constraints or process requirements. The presented system includes a supervisory desktop computer with specifically developed Data Acquisition software. Arduino UNO Microcontroller Development Board is used for drive speed and directional control using Pulse Width Modulation (PWM) technique. Data transfer from desktop to controller and controller to desktop is done using the Serial Port Connectivity (SPC) of the microcontroller. Microsoft Visual Studio is used to develop the necessary GUI Software System. VB.NET is used as the backend programming language for drive control and data acquisition. The data acquired can be stored into Microsoft Excel Workbook for further analysis and the speed v/s voltage characteristics can be saved as an image file. [ABSTRACT FROM AUTHOR]

In the direct drive motion system, there are obvious feedback harmonics caused by the various disturbances, which have important influence on the thrust characteristics of the permanent magnet synchronous linear motor (PMSLM). This paper presents the influence of the feedback harmonics on the detent force for the direct drive motion system. Firstly, the Maxwell's equation and the Schwarz–Christoffel (SC) mapping‐based method are used to accurately establish the magnetic field model in the air‐gap considering the slotting effect and end effect. Then, based on the control model of the motion system, the drive current caused by the feedback harmonics are calculated considering the non‐linearity of the drive circuit. The detent force of PMSLM is analytically represented and analyzed. Finally, the validity of the theoretical analysis is verified by the finite‐element method (FEM) and experiments. The results shown that the feedback harmonics will be coupled with the detent force and intensify the couplings among different sources of the thrust harmonics, which will lead to new coupled thrust harmonics, deteriorating the dynamic precision of the direct drive motion system. [ABSTRACT FROM AUTHOR]

Frustration is an unpleasant emotion prevalent in several target applications of affective computing, such as human-machine interaction, learning, (online) customer interaction, and gaming. One idea to redeem this issue is to recognize frustration to offer help or mitigation in real-time, e.g., by a personal assistant. However, the recognition of frustration is not limited to these applied contexts but can also inform emotion research in general. This paper presents a dataset of 43 participants who experienced frustration in driving-related situations in a simulator. The data set contains a continuous subjective label, hand-annotated face and body expressions, facial landmark coordinates of two cameras, and the participants’ age and sex information. In addition, a descriptive analysis and description of the data's characteristics are provided together with a Graph Convolution Network based model to recognize frustration. Allowing for a tolerance of 10%, the model could correctly identify frustration with a similarity of 79.4 % and a variance of 7.7 %. This work is valuable for researchers of the affective computing community because it provides realistic data with an in-depth description of its characteristics and a benchmark model for automated frustration recognition. Our FRUST-dataset is publicly available under: https://ts.dlr.de/data-lake/frust-dataset/dataset.zip. [ABSTRACT FROM AUTHOR]

This paper investigates the stray magnetic and electric fields of a multifunctional power converter operation while connected to a system involving an induction motor. The impacts of the switching techniques on the radiated fields of the converter were studied for the purpose of electromagnetic interference (EMI) evaluation and fault detection. This was achieved through the inspection of the magnetic and electric fields. Two of the most commonly used switching techniques were implemented through a hardware-in-the-loop system studied in terms of the stray. Various fault and failure conditions were applied to the converter to monitor the converter condition through the stray field observations. A coil and a rod antenna were connected to an EMI receiver to capture the fields. The fields were employed in further analyses. The harmonics and interharmonics of the stray fields were studied in detail for system monitoring purposes. The importance of this paper is to enable the evaluation of the optimum switching pattern for lower EMI field levels from the converter and for condition monitoring and fault diagnosis purposes. [ABSTRACT FROM AUTHOR]

Conventional model predictive control (MPC) for three-level active neutral point clamped converter (ANPC) utilizes weighting factors to achieve the optimal control of multiple control objectives in a single cost function. However, the selection of these weighting factors has an impact on the performance of the controlled objectives significantly. Tuning of weighting factors is usually tedious and lacks theoretical background. Moreover, the predictive and evaluation process for multiple objectives optimization have to be carried out by enumerating all admissible switching states within one loop. To simplify the complexity of this process and eliminate the effect of weighting factors, this paper proposes a cascaded predictive control scheme for a 3L-ANPC inverter fed induction machine (IM) drive. With the proposed approach, three separate cost functions for three control objectives, stator flux vector, neutral point voltage and device loss distribution are evaluated in a cascaded way, so that the optimization of these control objectives is performed independently. A 3L-ANPC inverter driven IM drive is studied in this paper to verify the effectiveness of the proposed algorithm. Experimental results in different operating conditions confirm that the proposed method achieves satisfactory steady-state and transient performances comparable to the conventional predictive control approach. The weighting factors used in the conventional method are eliminated and the computational effort is reduced by 68% compared to the conventional method without any sacrifice in the drive performance. [ABSTRACT FROM AUTHOR]

This paper urges that if we wish to give social intelligence to our agents, it pays to look at how we acquired our social intelligence ourselves. We are born with drives and motives that are innate and deeply social. Next, as children we are socialized to acquire norms and values and to understand rituals large and small. These social elements are the core of our being. We capture them in the acronym GRASP: Groups, Rituals, Affiliation, Status, Power. As a consequence, economic rationality or logical reasoning do not suffice when it comes to social intelligence. Basic features of our social behaviour, of the kind that one sees early in the lives of children, need to be prominent. These include fear, love, and aggression. They extend to the combination of these drives with basic social clues from the environment such as big and small, good and bad, as well as culture-specific specializations of these. This will make agents respond differentially to inferred attributes such as gender, age, group membership. This level of universality in social intelligence should receive our full attention. The general insights gained can then be re-used in myriad implementations to specific modelling issues. [ABSTRACT FROM AUTHOR]

Synchronous induction coilgun (SICG) has attracted more and more attention due to its advantages of simple manufacturing and no physical contact between armature and barrel. The armature, as an important component of SICG, will directly affect the launch speed and energy conversion efficiency. According to the distribution characteristics of eddy current and electromagnetic force, a new structural armature is proposed in this paper. The proposed inner conical armature is characterized by the maximum thickness at the tail end and the minimum thickness at the front end, with a gradual decrease in the thickness along the axial direction. The simulation results reveal that the proposed armature not only increases the mutual inductance between the armature and the drive coil but also enhances the electromagnetic force and weakens the armature capture effect. The experimental results verify that, compared with a traditional armature weighing 56.5 g, the new structure armature weighing 58.0 g enables higher muzzle velocities using the same set of pulsed power supply and drive coil, providing higher efficiency. [ABSTRACT FROM AUTHOR]

This article presents an optimal model predictive flux control (MPFC) for a two-level inverter fed induction motor. Integrating discrete SVM into FCS-MPFC enhances the performance of the IM drive. However, conventional DSVM-MPFC requires to enumerate and evaluate a higher number of virtual vectors in the prediction loop. In this paper, a high-efficient and low complexity voltage selection method is proposed to reduce the number of candidate voltage vectors from 38 to 15 without any suboptimality. Both steady-state and transient performances of the proposed method remain the same as the 38-vector based conventional DSVM-MPFC, producing the same cost-function values in all operating conditions. Furthermore, an online switching frequency reduction technique is proposed to achieve a minimum commutation per inverter vector change within each sampling cycle and between adjacent cycles. By appropriately arranging the sequence of real voltage vectors in each sampling cycle, a lower average switching frequency is achieved. The proposed switching frequency reduction method decreases the switching losses without compromising the performance of DSVM-MPFC as only the applied sequences of the real voltage vectors are optimized. Experimental studies are conducted to verify the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

This paper presents an adaptive fixed-time convergent continuous controller designed to solve a stock management problem with the objective to drive stock and supply chain levels at the reference values, subject to loss rate disturbances whose bounds are unknown. The only measurable state of the supply chain is the inventory retailer stock level, whereas the supply line inventory level should be estimated. The designed controller includes a fixed-time convergent differentiator, an adaptive fixed-time convergent disturbance observer, and a fixed-time convergent regulator. The adaptive fixed-time convergent observer is used to estimate a disturbance without excessively increasing the controller gains. The controller design is validated in a case study of stock management. The calculated upper estimate for the total settling (convergence) time and the obtained simulation results confirm the fixed-time convergence and the robustness of the designed controller. [ABSTRACT FROM AUTHOR]

Solid state drives (SSDs) have been widely deployed in personal computers, data centers, and cloud storages. In order to improve performance, SSDs are usually constructed with a number of channels with each channel connecting to a number of nand flash chips, each flash chip consisting of multiple dies and each die containing multiple planes. Based on this parallel architecture, I/O requests are potentially able to access parallel units simultaneously. Despite the rich parallelism offered by the parallel architecture, recent studies show that the utilization of flash parallel units is seriously low. This paper shows that the low parallel unit utilization is highly caused by the access conflict among I/O requests. In this paper, we propose parallel issue queueing (PIQ), a novel I/O scheduler at the host systems. PIQ groups I/O requests without conflicts into the same batch and I/O requests with conflicts into different batches. Hence, the multiple I/O requests in one batch can be fulfilled simultaneously by exploiting the rich parallelism of SSDs. Extensive experimental results show that PIQ delivers significant performance improvement especially for the applications which have heavy access conflicts. [ABSTRACT FROM PUBLISHER]

This paper presents yaw and pitch micro-electromechanical system gyroscopes embedding four active nanoelectromechanical (NEMS) piezoresistive gauges each, two of which are used for differential sensing of the Coriolis motion, and two of which are innovatively used to sense the drive motion and thus to close the drive oscillation loop. After presenting the devices design, this paper discusses the advantages of this particular implementation in terms of operating voltages, electrical equivalent model, and temperature behavior of the scale factor. In operation with voltages lower than 1.8 V without voltage boosting, the devices show sub mdps/ \surd Hz noise density within areas of about 1 mm2 per device at 0.2-mbar package pressure. Under temperature sweeps, a 3.7-fold better immunity of the scale factor stability is obtained, compared with a similar gyroscope embedding combs (and not NEMS) for drive detection. [2017-0050] [ABSTRACT FROM PUBLISHER]

Once upon a time, there was a cement kiln with a 5500-HP induced draft (ID) fan powered by a wound rotor induction motor. The process controlled the airflow with an inlet damper operating in 35% open range. The plant wished for a more energy efficient means of controlling airflow and power demand for this fan. This paper reviews the options and decision processes that made this wish come true. A novel method was used to reduce the power consumed and control the fan's speed based on a lower airflow demand. The solution was implemented with participation from the utility, the energy saving consultants, and the equipment suppliers. This paper also covers the challenges presented by the ID Fan wound rotor motor design, the plant operational situation, and the technology selected to solve the problem. Details of the wound rotor motor speed control will be discussed and its application reviewed. The significant energy savings and process improvements are covered as well. [ABSTRACT FROM PUBLISHER]

The paper provides an overview of the designs of cogwheels contained in modern literature, patents, and inventor certificates. Structures are described that make it possible to ensure the dismantling of wheels, reduce contact stresses, and increase the durability and bearing capacity of the wheels. [ABSTRACT FROM AUTHOR]

LSM-tree based Key-value (KV) stores greatly fit the needs of write-intensive applications with its efficient data store and retrieval operations to datasets. To accommodate ever-growing datasets, shingled magnetic recording (SMR) drives have become a popular option to provide large storage capacity for KV stores at low cost. SMR drives achieve high storage density via overlapping tracks on the disk surface. However, the overlapped track layout induces the sequential-write constraint and prevents KV stores from storing and rearranging KV pairs efficiently. In this paper, we present KVSTL, a KV store aware Shingled Translation Layer (STL), to preserve the merits of existing KV stores, while exploiting the high storage density of SMR drives. KVSTL is proposed as an application support to hide the management complexity of SMR drives and facilitates the management of SMR drives via passing only the “level” and “invalidation” information of LSM-tree based KV stores onto SMR drives. The proposed KVSTL achieves its performance enhancement via managing key-value pairs with level awareness and enabling efficient storage space management with the invalidation information. The results show that KVSTL can reduce the written data amount for 69.45 percent on average and the latency for up to 62.72 percent when compared with SMR-based LevelDB. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic makes wearing masks mandatory in supermarkets, pharmacies, public transport, etc. Existing facial recognition systems encounter severe performance degradation as the masks occlude key facial regions. Recently, simulation-based methods are proposed to generate masked faces from unmasked faces. However, among simulated faces, there are low-quality samples with negative occlusion, which leads to ambiguous or absent facial features. In this paper, we propose a consistent sub-decision network to obtain sub-decisions that correspond to different facial regions and constrain sub-decisions by weighted bidirectional KL divergence to make the network concentrate on the upper faces without occlusion. In addition, we perform knowledge distillation to drive the masked face embeddings towards an approximation of the original data distribution to mitigate the information loss. Experiments show that the proposed method performs better than the baseline on public masked face recognition datasets, i.e., RMFD, MFR2, and MLFW. [ABSTRACT FROM AUTHOR]

Induction coil launcher (ICL) is an electromagnetic accelerator that uses Lorentz force to accelerate a projectile with a conducting armature. In this paper, the effects of the height and starting position of the armature on the performance of the ICL were analyzed. Launching experiments were conducted to verify the analysis results. The speed of the projectile converged to a saturated value as the armature height increased. We found that there exists an optimal starting position of the armature for the highest speed. The concept of inductance gradient was adopted to explain the analysis results. It was possible to predict the acceleration characteristics and to estimate the optimal starting position using this concept. Results show that the armature height should be longer than the drive coil height ( \textH\mathrm {coil}) , and the bottom of the armature should be positioned between (1/4)H\mathrm {coil} and (1/2)H\mathrm {coil} at the start to obtain the highest speed. The experimental results showed good agreement with the simulation analysis results. [ABSTRACT FROM AUTHOR]

Solid-state drives (SSDs) based on NAND flash are making deep inroads into data centers as well as the consumer market. In 2016, manufacturers shipped more than 130 million units totaling around 50 Exabytes of storage capacity. As the amount of data stored on solid state drives keeps increasing, it is important to understand the reliability characteristics of these devices. For a long time, our knowledge about flash reliability was derived from controlled experiments in lab environments under synthetic workloads, often using methods for accelerated testing. However, within the last two years, three large-scale field studies have been published that report on the failure behavior of flash devices in production environments subjected to real workloads and operating conditions. The goal of this paper is to provide an overview of what we have learned about flash reliability in production, and where appropriate contrasting it with prior studies performing controlled experiments. [ABSTRACT FROM PUBLISHER]

In this paper, it is mainly aimed to study the working condition when there exists multiple armatures in launch tubes in the process of hyper velocity launching of the electromagnetic coil launcher. On the basis of understanding the single stage induction coil launch principle, this article expounds the working process of this kind of condition, and based on the circuit principle, an electrical and mechanical model for continuous emission of electromagnetic coil launcher with multiple armatures is set up. Through systematic description to the launcher equivalent circuit and the control equation, thrust equation and equation of motion, it further expounds the mechanism of the launcher. Dynamic simulation and structural design of electromagnetic coil launcher is conducted based on established parameters. Finally, the results of theoretic analysis and simulation design were further verified by the experiment, and the results of this paper are achieved. [ABSTRACT FROM PUBLISHER]

Electric submersible pumps (ESP) are used in a wide-range of applications from onshore to complex offshore, deep water, or subsea applications. Premature failures are undesired as they result in repair or replacement costs, but worse- downtime. This paper presents the challenges faced by the authors at an onshore oil field. The site experienced several ESP failures after drilling and operating 10% of the planned 300 wells. The authors were tasked to determine if power quality was a contributing factor in the premature failures and recommend a solution to prevent future occurrences. In addition to the failures, the oil field operator was concerned with the harmonic currents that would be generated once all 300 wells were online. The oil field is in an industrial area where large amounts of harmonic currents would increase voltage distortion to neighboring establishments and possibly lead to process disruption or equipment failure. [ABSTRACT FROM PUBLISHER]

A cam-based shear force-actuated electromechanical valve drive system offering variable valve timing in internal combustion engines was previously proposed and demonstrated. To transform this concept into a competitive commercial product, several major challenges need to addressed, including the reduction of power consumption, transition time, and size. As shown in this paper, by using nonlinear system modeling, optimizing cam design, and exploring different control strategies, the power consumption has been reduced from 140 to 49 W (65%), the transition time has been decreased from 3.3 to 2.7 ms (18%), and the actuator torque requirement has been cut from 1.33 to 0.30 N·m (77%). [ABSTRACT FROM PUBLISHER]

When an emergency happens to electric vehicles, the voltage of the dc-bus capacitor, which is an important part of the permanent magnet synchronous machine (PMSM) drive system, requires to be reduced as quickly as possible. Recently, a new idea of directly using the windings to discharge the capacitor has come forth. This paper proposes a physical energy flow model (EFM) to explain explicitly the winding-based discharge mechanism first. In the EFM, the performance characteristics of the classical winding-based discharge scheme are evaluated, but it is found that the discharge time will not be qualified when the machine rotor inertia is large and the system safe current is small. In order to reject intense voltage surge, a current control algorithm is proposed to bleed the capacitor voltage. Moreover, the proposed current control method shortens the discharge period to below 3 s for the system studied. The proposed discharge algorithm is verified by the experiment that is conducted on a three-phase PMSM drive system. [ABSTRACT FROM AUTHOR]

This paper proposes a variable structure speed controller (VSSC) that guarantees the robust transient performance against the external disturbances and parameter uncertainties of an interior permanent magnet synchronous motor (IPMSM) drive. Unlike the conventional VSSC applied to the IPMSMs, the proposed nonlinear compensating control term not only assures the robustness against the system uncertainties, but also implements the maximum torque per ampere technique. Furthermore, the convergence and stability of the proposed VSSC are fully proven through the Lyapunov theory by introducing reasonable bounded uncertainties which determine a feasible range for the system dynamics. The effectiveness of the proposed scheme is investigated through the simulation using MATLAB/Simulink and experiment using a prototype IPMSM drive system with a TI TMS320F28335 DSP. Finally, the proposed VSSC can ensure faster and more robust transient response than the conventional proportional-integral speed controller under the dynamic load conditions including the uncertainties. [ABSTRACT FROM AUTHOR]

Incipient faults in electrical drives can corrupt overall performance of high-speed trains; however, they are difficult to discover because of their slight fault symptoms. By sufficiently exploiting the distribution information of incipient faults, this paper presents the reason why incipient faults cannot be detected by the existing fault detection and diagnosis (FDD) methods. Under principal component analysis (PCA) framework, we propose a new data-driven FDD method, which is named probability-relevant PCA (PRPCA), for electrical drives in high-speed trains. The salient strengths of the PRPCA-based FDD method are: 1) it can greatly improve the fault detectability; it is suitable for non-Gaussian electrical drives; 2) based on the improved fault detectability, it can achieve accurate fault diagnosis via support vector machine; and 3) it can be easily applied to electrical drives even if neither physical models or parameters nor expert knowledge of drive systems is given; and it is of highly computational efficiency that can meet requirements on the real-time FDD. A set of experiments on a dSPACE platform-based traction system of the CRH2A-type high-speed train are carried out to demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Growing demand for key-value store applications is building a strong momentum for the commercialization of key-value hard disk drives. To achieve better performance, flash-based solid state drive is the next ideal candidate for commercialization in the foreseeable future. However, the existing fixed-sized management strategies of flash-based devices would potentially result in low storage space utilization when managing variable-sized key-value data. In addition, the low storage space utilization would further lead to the degradation of device performance, due to low invalid data space reclamation efficiency. The space utilization issue motivates this paper to propose a key-value flash translation layer design to improve storage space utilization as well as the performance of the key-value solid state drives. A series of experiments was conducted to evaluate the proposed design, and the experiment results of space utilization and device performance are very encouraging. [ABSTRACT FROM AUTHOR]

This paper presents a new and very simple strategy for torque and flux control of ac machines. The method is based on model predictive control and uses one cost function for the torque and a separate cost function for the flux. This strategy introduces a drastic simplification, achieving a very fast dynamic behavior in the controlled machines. Experimental results obtained with an induction machine confirm the drive's very good performance. [ABSTRACT FROM AUTHOR]

This paper deals with the identification of mechanical backlash in drives. The development of a reliably working identification method is intended. The method presented in this paper is considered to be a necessary step toward the development of more complex diagnosis tools and condition monitoring systems that are demanded today in the area of servodrives. The main idea for identifying backlash is explained. Measurement results clearly point out the efficiency of the identification strategy proposed in this paper. Thus, the results of the identification can be utilized for the tuning of the controller or for the diagnostics of the actual state of the drive. [ABSTRACT FROM AUTHOR]

This paper deals with the measurement of the frequency response of the mechanical part of a drive for the parameter identification of a plant. The system is stimulated by pseudorandom binary signals. The measurement of the frequency response is part of a system identification procedure being carried out during an automatic commissioning of the drive. For the calculation of the frequency response of the mechanics, the Welch-method is applied for spectral analysis. The Welch-method is known from the fields of communications and measurement engineering. This paper addresses the application of this powerful method for the identification of electrical drives. Investigations have pointed out that the pure utilization of conventional identification strategies does not yield satisfying experimental results. Experimental results presented in this paper point out clearly the efficiency and flexibility of the proposed Welch-method. This paper contains many practical aspects and realization details that are important for their implementation on industrial systems. Although in principle, commercial software tools can be utilized for identifying the parameters of the plant, this paper addresses the implementation of the necessary identification algorithms on the embedded control electronics of the drives. The utilization of the Levenberg-Marquardt-algorithm yields excellent results for the identified parameters on the basis of the measured frequency response data. [ABSTRACT FROM AUTHOR]

Motivation and emotions have been area of interest for philosophers, psychologists and neuroscientist. Researchers and scientists want to have human like intelligent robots which are self-aware and self-motivated. Motivational robots are autonomous and intelligent which can set goals and then take actions to achieve their goals independently. Moreover, intelligence in robots is not possible without autonomy and autonomy is incorporated in robots through motivation. Nowadays, attention is being paid to build robots which have computational and energy autonomy. In Literature, various motivational architectures have been presented but none seems to focus on the development of human inspired motivation in robots comprehensively. These architectures try to achieve mere functional motivation in limited way, some considered only time for the regulation of drives, others failed to incorporate physiological and psychological aspects of human motivation. To the best of our knowledge, no architecture is truly based on the physiology and psychology of humans has been considered in the literature. To solve this problem, this paper proposes a motivational architecture for autonomous robots to make them independent in deciding the goals and taking actions. The proposed architecture is primarily based on physiology and psychology of human motivation through basic human drives (hunger, thirst and sleep), emotions and glucose-insulin theories. The whole process of drives regulation is based on stimulation and satiation. The intensity of the drives and the emotional states help in setting the goal and accordingly a suitable action is taken to meet the particular goal. Empirical results show that glucose and insulin have direct relationship with basic drives and emotions in the process of intrinsic motivation generation. The proposed architecture has applications in industry, education and autonomous robots. The proposed motivational architecture has significant advantages over several state-of-the-art architectures in terms of autonomy through intrinsic motivation. [ABSTRACT FROM AUTHOR]

Future transportation challenges include a considerable reduction in pollutant emissions at a time when significant increase in demand is predicted. One of the enabling solutions is the electrification of transport systems as this should lead to improved operability, fuel savings, emission reduction, and maintenance. While state-of-the-art technology has demonstrable benefits there needs to be considerable advancement to meet future transportation affordability and emission targets. Primarily, electrical drives need an improved power density, an increased reliability, and a reduced specific cost. For this reason, integrated modular motor drives (IMMDs) present an attractive solution. Modularity leads to redundancy and easier integration. This paper presents a novel speed-drooped control system applied to motors fed by modular paralleled converters. This control technique allows precise speed regulation and power sharing among different segments showing improved fault tolerance and reliability. The design procedure and the power sharing dynamic have been presented and analyzed by means of MATLAB/Simulink and validated in a 3-kW experimental rig, showing good agreement with the expected performances. [ABSTRACT FROM PUBLISHER]

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New technology in digital excitation control provides a method to balance thyristor currents in parallel power rectifier bridges that provide current to a synchronous generator field. Balancing current between parallel bridges feeding a common load has traditionally been accomplished by using current balancing transformers in each bridge or adding inductance in series with the thyristors or silicon controlled rectifiers (SCRs). This paper introduces active current balance, a new technique that modifies the average current in parallel leg thyristors to facilitate current balance between the bridges. This is accomplished by periodically inhibiting the firing of thyristors that carry more than the average current. The thyristors that are fired carry more current during this interval, increasing their average current. The thyristors that are not fired do not carry current during this interval and thus their average current is reduced. Using this technique (referred to in this article as "skip firing"), the average current in parallel legs can be adjusted through feedback and control to equalize the average thyristor current loading. Additional feedback and control parameters are proposed, such as heatsink temperatures, which can be measured and utilized to program the "skip firing," in order to balance thyristor heat-sink temperatures. [ABSTRACT FROM PUBLISHER]

In this paper, the usability of the classical Harmonic Balancing method (cHB) to calculate the weakly nonlinear motion of phase- and amplitude controlled MEMS resonators is demonstrated. A polynomial mechanical stiffness description and linearized electrostatic effects are considered, which allow determining the Jacobian analytically. The effects of amplitude and phase control are taken into account by applying boundary conditions in the iteration process. With a customized cHB, it is possible to efficiently simulate the behavior of a MEMS gyroscope undergoing nonlinear resonance with higher parasitic modes. The presented results of a virtual model compare very well with solutions obtained with the Shooting method. Furthermore, we compare the measurement of a drive frequency discontinuity, taken from a different prototype, with the prediction from our linear extrapolated model and from a model with artificially fitted parameters. The cHB approach yields an order of magnitude speed-up in comparison to the transient simulation method. Besides some restrictions, customized cHB methods are interesting candidates for fast system-type simulation considering the MEMS-ASIC interface. [2021-0028] [ABSTRACT FROM AUTHOR]

A drive-system-based modeling approach for electromagnetically excited noise-vibration-harshness (NVH) simulation of a disc rotor permanent-magnetic axial-flux synchronous motor is introduced. The electric motor type requires a 3-D finite-element (FE)-based modeling for electrodynamics and magnetomechanical coupling. The methodic focus relies on orthogonal 3-D Fourier-representations for structural modal displacements and for magnetic force densities. The application of Galerkin-projection based on a supermesh construction between source FE meshes to equidistant 3-D grids is hereby required. A significant data reduction for model parametrization is achieved and a low-rank domain coupling matrix, including a high technical interpretability, is derived. Thus efficient NVH simulations of operation cycles including inverter and control influences can be performed within an order-reduced formulation. This paper is the first to derive a fully 3-D FE-based NVH analysis workflow for electric machines under realistic operating conditions for a routine industrial applicability. The high validity of the methodology is proven by a good agreement to real world measurements. [ABSTRACT FROM AUTHOR]

In this paper, we revisit an add-on output feedback controller that achieves output regulation and disturbance rejection. By add-on controller, we mean an additional controller, which runs harmonically with a preinstalled controller that has been in operation for the plant. When the disturbance attenuation performance of the preinstalled controller is not satisfactory, the add-on controller can be used to eliminate the disturbance. Some advantages of the proposed add-on controller include that it can be designed without much information about the preinstalled controller and it can be plugged in the feedback loop any time in operation without causing unnecessary transient response. In particular, we propose an adaptive add-on controller, which can eliminate sinusoidal disturbances of unknown frequencies. Both simulation and experimental results of the track-following control for optical disc drive systems confirm the effectiveness of the proposed method. [ABSTRACT FROM PUBLISHER]

The uniqueness of the electrical environment (asynchronous connection to power system, variable frequency operation, and harmonics) on the output of adjustable-speed drives (ASDs) requires special consideration to be given to the motor protection. The Working Group has investigated and addressed these concerns. This paper announces the report on the findings of this activity and the recommendations made to the motor protection engineer. The full report can be found at xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink"www.pes-psrc.org under Published Reports. [ABSTRACT FROM PUBLISHER]

The effect of redundancy on the aging of an efficient maximum distance separable (MDS) parity-protected distributed storage system that consists of MDS-parity protected array of storage units is explored. In light of the experimental evidences and survey data, this paper develops generalized expressions for the reliability of array storage systems based on more realistic time to failure distributions such as Weibull. For instance, a distributed disk array system is considered in which the array components are disseminated across the network and are subject to independent failure rates. Based on such, generalized closed-form hazard rate expressions are derived. These expressions are extended to estimate the asymptotical reliability behavior of large-scale storage networks equipped with MDS parity-based protection. Unlike previous studies, a generic hazard rate function is assumed, a generic MDS code for parity generation is used, and an evaluation of the implications of adjustable redundancy level for an efficient distributed storage system is presented. Results of this paper are applicable to any erasure correction code as long as it is accompanied with a suitable structure and an appropriate encoding/decoding algorithm such that the MDS property is maintained. [ABSTRACT FROM PUBLISHER]

This paper presents design and digital implementation of a fuzzy controller for achieving improved performance of Brushless dc (BLDC) servomotor drive. The performance of fuzzy and PID controller-based BLDC servomotor drives is investigated under different operating conditions such as change in reference speed, parameter variations, load disturbance, etc. BLDC servomotors are used in aerospace, instrumentation systems, space vehicles, electric vehicles, robotics, and industrial control applications. In such applications, conventional controllers like P, PI, and PID are being used with the BLDC servomotor drive control systems to achieve satisfactory transient and steady-state responses. However, the major problem associated with the conventional PID controller is that the tuned gain parameters obtained for such BLDC servomotor drive control systems do not yield better transient and steady-state responses under different operating conditions such as parameter variations, load disturbances, etc. In this paper, design and implementation of fuzzy controller is presented and its performance is compared with PID controller to show its capability to track the error and usefulness of fuzzy controller in control applications. [ABSTRACT FROM PUBLISHER]

Permanent-magnet-assisted synchronous reluctance (PMSynRel) machines are generally well suited for sensorless operation at all speeds since the rotor topology possesses a magnetic saliency. However, magnetic saturation can result in a vanishing differential saliency which renders sensorless control at certain operating points difficult (or even impossible) at low speed. In this paper, an optimization procedure, based on results from finite-element (FEM)-based simulations, is proposed. As output, current reference trajectories are obtained in which copper losses are kept at minimum, while the capability for sensorless control is still maintained. The results from the FEM-based simulations are in good agreement with the corresponding experimental results. For the experimental prototype in consideration, the torque limit when operating sensorless at low speed is increased substantially from below 45% to around 95% of its rated value with only slightly increased copper losses. Additionally, the impact of position-dependent harmonics on the magnetic cross saturation (affecting the steady-state position estimation error) is found to be substantial. This highlights that this spatial variation should be taken into consideration for accurate prediction of performance during sensorless operation even if the winding of the machine is of the conventional distributed type. [ABSTRACT FROM PUBLISHER]

This paper reviews the reliability of solid-state drives (SSDs) based on NAND Flash memory from the perspectives of failure mechanisms, design mitigations, qualification methods, and field failure rates. NAND reliability is dominated by gradual memory-cell degradation in late life and defects such as interconnect shorts earlier in life. Design mitigations exist for these mechanisms. Qualification methods standardized in JEDEC JESD218 are designed to evaluate the mechanisms and mitigations, over a full drive lifetime, in the laboratory. Full-lifetime qualification provides confidence in the long-term reliability of SSDs that cannot be achieved by the early-life qualifications performed on hard disk drives. If NAND mechanisms are sufficiently suppressed, field reliability will be dominated by non-NAND mechanisms such as firmware bugs, power-loss events, radiation-induced soft errors, and failures in non-NAND components. A wide range of design validation and qualification tests are necessary to evaluate these non-NAND mechanisms. Published field reliability statistics indicate that SSDs are more reliable on average than HDDs, but they are not immune to failure, and there is wide variation among models. The NAND and non-NAND mechanisms are illustrated through new case studies of SSD internal qualification and field reliability data. [ABSTRACT FROM PUBLISHER]

NAND Flash memories have changed and keep changing our lives. In the past two decades, NAND-based systems, in the form of Flash cards and USB keys, have replaced films and floppy disks. But disruption did not stop there. Today, NAND is really ubiquitous, as it plays the role of storage element inside smartphones and tablets; even further, it is now expanding its reach because solid-state drives (SSDs), i.e., drives built with several NAND devices, are replacing hard disk drives (HDDs) in more and more applications. To fuel this continuous evolution, NAND has to remain very aggressive in terms of cost per bit. When approaching 10-nm technologies, planar NAND is running out of steam: industry and academia have worked hard on finding a solution to this problem for more than a decade. Three-dimensional integration turned out to be the most promising alternative, and it is now eventually reaching the market. This paper is about 3-D NAND Flash memories and the related integration challenges. Charge trap and floating gate 3-D technologies will be discussed with the aid of several bird’s-eye views. Advanced layout techniques will thoroughly be analyzed. Finally, future scaling trends will be presented. [ABSTRACT FROM PUBLISHER]

In the past decade, flash memory has been in the spotlight across a variety of research communities from circuits to computer systems, and significant progress has been accomplished. This has enabled flash memory to become increasingly pervasive across the entire information technology infrastructure, from consumer electronics to cloud and supercomputing. This paper aims to provide a comprehensive survey on the important advancements and milestones in the domains across flash translation layer (FTL), operating systems, and applications. As the storage device hardware has been quickly commoditized, software becomes increasingly important to tap the potential of flash memory to its full extent. Therefore, a comprehensive survey with a focus on software aspects will be very valuable to the research community and industry. It is our hope that this survey paper will serve as a good reference for system practitioners and researchers. [ABSTRACT FROM PUBLISHER]

This paper reviews the recent historical trends of the NAND Flash technology, highlighting the evolution of its main parameters and explaining what allowed it to become not only the most important integrated solution for nonvolatile storage of high volumes of data but also a strong rival eroding the market share of hard-disk drives. The scaling trend followed by planar arrays will be discussed with close attention, along with the major physical constraints impacting the performance and the reliability of modern deca-nanometer technologies. This will make clear why the development of further planar nodes with feature size below ~15 nm, representing today’s state of the art, can be considered less favorable than turning all the efforts toward the integration of 3-D arrays. The most promising 3-D architectures will then be reviewed, discussing their benefits and issues and addressing the impact of the change of the integration paradigm from the standpoint of the major NAND applications. [ABSTRACT FROM PUBLISHER]

The world of legal responsibility, liability, and safety is driving the industry to have equipment built to an increasing number of standards. End users and specifiers often require adjustable-speed drives (ASDs) to be in compliance with many standards like the International Electrotechnical Commission (IEC), National Electrical Manufacturers Association (NEMA), American National Standards Institute, Canadian Standards Association, Underwriters Laboratory, etc. This is done to insure that they are protected in buying products that are built to high standards. Depending on the specifier, European and/or North American standards may be referenced and required to be met. However, what is required to meet these standards is often not understood. Sometimes, the details of the standards are in conflict with each other. This paper will attempt to compare major areas of the existing standards for similarity and differences. European IEC standards will be compared to the most applicable North American standards. The goal of this paper will be to help the readers better understand what the standards mean to their plants and how they can then include standards in their specifications that will best meet their requirement, yet do so in a cost-effective manner. [ABSTRACT FROM AUTHOR]

The majority of current robotic joints are primarily actuated by rotational mechanisms. These electrical drives have substantially different features than the features found in human muscular systems. This paper presents a cost-effective solution to the backlash of a phenomenon known to cause positioning errors and other undesirable dynamic effects in drives. These errors are particularly pronounced when relatively major changes appear in the pre-load conditions of the motor such as in the case of a robotic leg or arm with a high degree of freedom. Current solutions require an accurate time-varying model of drives that is not available in the majority of practical cases. Therefore, in this paper a digitally controlled mechanical solution is proposed which is inspired by the human flexor–extensor mechanism. The idea is to construct an antagonistic actuator pair analogous to the flexor and extensor muscles. In order to obtain good control performance even in the low-speed range, permanent magnet stepper motors were chosen as actuators that are commutated in a digitally closed-loop fashion. The operation of the controlled structure has been verified in a real experimental environment where measurements showed good results and match with previous simulations. [ABSTRACT FROM PUBLISHER]

This paper proposes a method that allows the operation with direct torque control under incipient faults of the power switching devices in single dc-link dual inverters. Once the fault onset of the switching device is detected, the troubled devices are put under trigger suppression to regain operation. The proposed control algorithm makes use of additional states, termed opportunistic states, to maintain control of the induction machine. Simulations and experimental results confirm the capabilities of the technique for up to six devices under trigger suppression. [ABSTRACT FROM AUTHOR]