Toomas Vaimann

Toomas Vaimann
Tallinn University of Technology | TTU · Department of Electrical Power Engineering and Mechatronics

PhD

About

246
Publications
104,922
Reads
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1,537
Citations
Citations since 2016
195 Research Items
1430 Citations
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Introduction
Toomas Vaimann currently works at the Department of Electrical Engineering and Mechatronics, Tallinn University of Technology. His main research interest is condition monitoring, diagnostics and prognostics of electrical machine faults.
Additional affiliations
September 2019 - present
ITMO University
Position
  • Professor
September 2015 - present
Tallinn University of Technology
Position
  • Senior Researcher
February 2015 - April 2017
Aalto University
Position
  • Researcher

Publications

Publications (246)
Article
Full-text available
The hairpin winding configuration has been attracting attention as a solution to increase the power density of electric vehicle motors by enhancing the slot-filling factor. However, this winding configuration brings high AC losses during high-speed operation and we require new approaches to tackle this challenge. This paper considers reducing AC lo...
Conference Paper
In the electric automotive industry, manufacturers usually do not declare the electrical parameters of electric vehicle (EV) motors. In advanced control systems, accurate knowledge of motor parameters is essential in order to achieve high dynamic performance. Conventional tests for parameter estimation might be risky not only to the motor windings...
Chapter
Internet of Things (IoT) has become the need of the hour with the recent advancement in technology. The emergence of new technologies has helped to communicate between different machines and it has become easier to interact with them. This has helped with the reduction of maintenance costs and the time needed to fix the machine. Furthermore, it is...
Conference Paper
Cartesian robot is a complex industrial robot, which is designed to work in hard and dangerous human conditions. This kind of robot has some control modes that help transform it for different tasks, such as movement details, 3D-printing, accuracy cutting processes, and others. Hirata cartesian robot is chosen for research in the paper. Additional v...
Article
Full-text available
In order to define the best design structure of the synchronous reluctance motor (SynRM) rotor, optimization must be carried out, implying the selection of the best alternative for each specific criterion. The optimization of an electrical machine is a complicated work involving meeting different criteria requirements while dealing with a range of...
Conference Paper
Nowadays, electrical machines and drive systems are used in numerous domestic and industrial applications. Due to this fact, unexpected failures can lead to fatal consequences and are to be prevented. As the world is moving towards Industry 4.0 standards, sophisticated technologies and timely fault detection are becoming more popular. Using cloud c...
Conference Paper
Cartesian robots framework is a complex mechanical structure that consists of gearboxes, joints, and moving parts. The main problem with this structure is the impossibility to monitor any faults in mechanical parts that have occurred during work operations. An example of such a system, the Hirata cartesian robot, is described in the paper. The faul...
Conference Paper
Electrical machines play an essential role in numerous industrial applications. Modern energy systems, including wind turbines or electric vehicles, are prone to damage and failures. In those devices, unexpected failures often mean economic loss, environmental problems, and danger to human life in the worst case. For developing a system that is abl...
Chapter
Full-text available
Nowadays, most domestic and industrial fields are moving toward Industry 4.0 standards and integration with information technology. To decrease shutdown costs and minimize downtime, manufacturers switch their production to predictive maintenance. Algorithms based on machine learning can be used to make predictions and detect timely potential faults...
Conference Paper
Nowadays, electrical machines are used in various applications and industrial branches, where unexpected damages are undesired and to be prevented. The world is moving towards Industry 4.0 standards, and sophisticated technologies are becoming more customary. Big data of machines’ working conditions can be stored remotely using cloud computation. T...
Conference Paper
-Increasing power densities in electrical machines create a demand for more powerful thermal solutions, which additive manufacturing can provide. However, the material properties of additively manufactured objects are unknown. In this paper, the anisotropic thermal conductivities of aluminum alloy (AlSi10Mg) and high-silicon steel (Fe-3.7%w.t.Si) s...
Article
Full-text available
In this article, a forward uncertainty propagation method is presented for a 2-D finite-element (FE) model in an induction machine. This method is applied to quantify the uncertainty of input parameters, for example, dimensions and material properties, and demonstrate their variability effect on harmonics related to the broken rotor bar (BRB) fault...
Conference Paper
The past decade has seen the development of additive manufacturing (AM) of functional electromagnetic components into a promising new area of research. The combination of previously unseen rapid prototyping capacity, coupled with its unparalleled design freedom, is bound to yield novel, previously unfeasible component designs. Several challenges re...
Conference Paper
This paper presents the basic design procedure for producing synchronous machines through conventional manufacturing techniques. The design procedure is explicitly adapted for synchronous reluctance machines with the proposed modifications, but individual portions can also be modified further for other machine types. The proposed changes in the des...
Article
Full-text available
The paper discusses problems that occur in robotic arm control. The specific problems arise due to the wear of various types of gears (in the presented case, belt gear and worm gear). It is important to note that such errors need to be diagnosed in time, and the way of their elimination has to be determined, which should be resource-intensive and c...
Article
-With growing interest in green technologies and sustainable transport, hybrid and pure electric powertrains are attracting a lot of attention. According to demanded metrics such as lightweight and high-power density motors, these offer clear motivation to develop advanced thermal management methods and integrate them with conventional cooling appr...
Article
Full-text available
Grid-powered pumping plants are widespread electromechanical systems commonly set in motion by electrical machines. The productivity of these electromechanical systems varies substantially according to the shift of the location of the working point on the H-Q plane, which is determined with the help of mutual positions of the characteristics of the...
Article
Full-text available
Additive manufacturing (AM) is considered the enabling technology for topology optimized components, with its unparalleled, almost free-form design freedom. Over the past decade, AM of electromagnetic materials has evolved into a promising new area of research. Considerable efforts have also been invested by the electrical machine (EM) research com...
Article
Full-text available
Over the past decade, additive manufacturing (AM) of functional electromagnetic components has grown into a promising new area of research. Not only does AM allow for unparalleled in-house prototyping speed and flexibility, but it also introduces a completely new set of design rules for obtaining optimized component shapes. Up to date, relatively f...
Article
This article proposes a hybrid analytical modelling procedure for the performance parameter estimation of synchronous reluctance machine, including its operation in the region of magnetic saturation. The proposed model better estimated the torque profile through improved translation and stepped transition of rotor flux barriers. The non-linear oper...
Article
Full-text available
This paper presents an analytical modelling technique based on modified winding function and co‐energy analysis, for characterisation of synchronous reluctance machines, in conjunction with a hybrid algorithm for mapping of the machine's operating point on BH curve and the corresponding performance parameters in non‐linear magnetic condition. The m...
Article
Full-text available
Additive manufacturing (AM) is a key technology for advancing many fields, including electrical machines. It offers unparalleled design freedom together with low material waste and fast prototyping, which is why it has become to focus of many researchers. For electrical machines, AM allows the production of designs with optimized mechanical, electr...
Article
Full-text available
Metal additive manufacturing (AM) technology is maturing. Although currently slower and less reliable than traditional production methods, AM systems shine when producing parts with unconventional topologies or in small quantities. Like countless other research communities, the electrical machine (EM) research community has shifted considerable eff...
Article
Full-text available
Renewables have passed the peak of the inflated expectation hype cycle for emerging technologies, but interest in the design of new energy conversion devices is still high due to widespread distributed energy systems for private households. Magnus effect-based wind turbine combines mechanical and electronic engineering that provides a broader wind...
Article
Full-text available
The concept of Digital Twin is creating and maintaining a digital representation of the real physical entity and supporting its performance utilizing simulation and optimization tools, which are fed with the real data obtained from the physical equipment. Development and implementation of the Digital Twin technology are one of the main challenges f...
Conference Paper
The paper presents the basic calculations, guidelines and procedures to determine the initial design parameters of a synchronous machine. This study aims to seek the adaptability of previously established design procedures for the continuously evolving design freedoms offered by additive manufacturing. An algorithm to implement this procedure has a...
Conference Paper
Bearing failures make the greatest proportion of damages affecting electrical machines. At the same time, there are various types of the bearing failures but the most common are related to damages caused by shaft currents in the machines leading to problems in industry. In this case, diagnostics and timely prediction of potential faults are importa...
Conference Paper
Condition monitoring of any electromechanical equipment is an essential tool to extend lifetime of the device and provide reliable work of the whole system. Due to friction mechanical subsystem is usually the weakest part of electromechanical equipment that. Early-stage diagnosis of that type of faults may save the equipment from serious failures....
Conference Paper
This paper presents a method for experimentally determining the thermal conductivity of additively manufactured specimens. Selective laser melting was used to fabricate two metal rods-one from an aluminum alloy (AlSi10Mg) and the other from silicon steel (Fe-3.7%w.t.Si) powder. For measuring the thermal conductivity, an experimental setup is design...
Article
Full-text available
Electrical machines are to face different challenging factors during operation, such as high unexpected or excessive loads, unusual properties of the working environment, or intense fluctuations in rotation speed. Therefore, maintenance questions and predicting the accuracy of an equipment’s condition have great importance. This study is based on t...
Poster
A hybrid model containing offline and online calculation procedures, for synchronous reluctance motor is presented in this paper. Via this modeling procedure, the initial design parameters of a synchronous reluctance motor can be obtained iteratively, with only a fraction of time involved as compared to the commercial finite-element-method based de...
Article
Full-text available
The significant progress in the electric automotive industry brought a higher need for new technological innovations. Digital Twin (DT) is one of the hottest trends of the fourth industrial revolution. It allows representing physical assets under various operating conditions in a low-cost and zero-risk environment. DTs are used in many different fi...
Article
Full-text available
This article presents an intelligent and accurate framework for fault diagnosis of induction motors using light gradient boosting machine (LightGBM). The proposed framework offers promising generalization ability when the testing data contains new unseen operating conditions unavailable during the training process. After the acquisition of vibratio...
Article
A discrete winding function analysis (DWFA) based approach for the modelling of skewed rotor cage-type induction motor with minimal simulation time is presented in this paper. The rotor slot skew has a significant attenuating impact on principal slotting harmonics (PSH) or rotor slotting harmonics (RSH). These harmonics can play a significant role...
Conference Paper
This paper investigates the hairpin winding configuration as a solution to increase the power density of electric vehicle motors by enhancing the slot filling factor. Moreover, the paper presents various manufacturing techniques of this winding and describes it in detail. Further, it provides a novel additive manufacturing method as an alternative...
Conference Paper
This paper presents an analytical thermal model of a synchronous reluctance motor to predict the temperature of its different parts using Motor-CAD. This software is commercial software, which develops the 3-D lumped parameter thermal network. The synchronous reluctance machine is used to validate the proposed approach. A test rig using a TEFC sync...
Article
Full-text available
Nowadays, electrical machines and drive systems are playing an essential role in different applications. Eventually, various failures occur in long-term continuous operation. Due to the increased influence of such devices on industry, industrial branches, as well as ordinary human life, condition monitoring and timely fault diagnostics have gained...
Conference Paper
This paper presents the calculation of the AC loss factor of a hairpin winding configuration using an analytical approach. For this purpose, the layer conductor model is developed to evaluate the AC loss factor. Moreover, the numerical model was created, and the collected numerical data was used to successfully validate the proposed analytical meth...
Conference Paper
This paper presents a comprehensive analysis of bearing fault impact on the vibration of brushless DC motors. This type motors are gaining heightened popularity because of their compact size, low cost, high torque, better control, and easy maintenance. They are becoming increasingly popular in low power applications such as electric scooters and ro...
Article
Full-text available
Motor-drive systems have the most significant share in industrial energy consumption, which requires a deep study in every aspect of the field. This paper presents a synchronous reluctance motor (SynRM) drive system based on Plecs RT box 1. The system's design provides the opportunity for the open-loop and closed-loop control of the motor and a cha...
Conference Paper
-This paper presents a comprehensive study of various bearing faults in electric scooter based brushless direct current motors. These motors are becoming increasingly popular because of their compact size, easy control, low cost, and high torque. Their applications are increasing particularly in the fields of low power electric vehicles and robots,...
Article
Full-text available
The growing need for intelligent machines, the outreach for more efficient use of the machines in industry, and the development of Industry 4 [...]
Article
Full-text available
This paper presents a case study on the development of the Attitude Determination and Control System (ADCS) of Tallinn University of Technology (TalTech) student CubeSat satellites (TTU100 satellite project). To determine the satellite’s attitude in orbit and its rotational speed, the satellites are equipped with sun sensors, magnetometers, and g...
Article
Full-text available
This paper presents the analytical calculation of the heat transfer coefficient of a complex housing shape of a Totally Enclosed Fan-Cooled (TEFC) industrial machine when it works below 20% of its nominal speed or close to stall. Therefore, passive cooling is dominant, and most of the heat is extracted by the combination of natural convection and r...
Article
Full-text available
Variable applications and methodologies are used in the Digital Twin technology. Digital Twin as a trending technology is also a general topic of many industry-oriented research projects. To develop and implement a novel technology, a detailed study of any single part of a system is required. This paper presents a development case study of the para...
Article
Full-text available
Additive manufacturing of ferromagnetic materials for electrical machine applications is maturing. In this work, a full E-type transformer core is printed, characterized, and compared in terms of performance with a conventional Goss textured core. For facilitating a modular winding and eddy current loss reduction, the 3D printed core is assembled f...
Conference Paper
The paper deals with diagnostic possibilities of induction motor bearing currents. As one of the most common electrical machine mechanical faults, failures in bearings have been the diagnostic interest for a long time. With the ever-growing amount of motors running with variable speed drives, the problems regarding bearing currents and related dama...
Conference Paper
This paper describes possibilities for reduction of bearing currents in induction motors. Growing usage of motors running with variable speed drives, the problems of bearing currents and related damages have become a significant issue in industry. Bearing currents cause a higher portion of faults in induction machines. Therefore, the maintenance qu...
Conference Paper
This paper presents the basic experimental procedures and calculations for determining the equivalent-circuit parameters of a small-scale commercial synchronous generator. The tests performed, are based on IEEE guide for synchronous generator test procedures and the IEC standards.