Ants Kallaste

• Doctor of Philosophy
• Professor at Tallinn University of Technology

With the continuous development of Artificial Intelligence (AI), designing accurate algorithms that provide diagnostics and maintenance of energy technologies is a challenging task in the energy transition domain. This research work focuses on the implementation of Transformer models for charge diagnostics and algorithm design of Battery Energy Sto...

Additive manufacturing has enabled the use of advanced geometries such as lattice-structures in heatsinks. This study investigates the thermal performance of various advanced heatsink designs in the context of cooling the windings of an axial flux motor using active air cooling. Physical samples of the heatsinks are additively manufactured from an...

In the context of rising power densities in electrical machines, additive manufacturing presents an opportunity to develop more powerful thermal solutions. However, the physical properties of objects manufactured using this process remain unclear. This research examines the directional thermal and electrical conductivities of aluminum alloy (AlSi10...

Additive manufacturing (AM) enables the creation of parts with exceptional geometric versatility, creating new possibilities for developing non-symmetrical electrical machines (EM) with compact structures, reduced mass density, high torque, better power density, and minimal material waste during fabrication. This review highlights the current state...

The various types of high-voltage instrument transformers (HVITs) play a highly significant role in the power system. They are necessary for routine operations such as control and monitoring, protection, and metering. However, HVITs remain vulnerable to defects due to high voltage or current based electric, magnetic, and thermal stresses. The defec...

The industrial revolution has opened up more paths with the integration of information technology with industrial applications. Similarly, most industrial processes can be streamlined by combining the Internet of Things (IoT) and artificial intelligence. Artificial intelligence has a significant role in this development, whether it is related to re...

This paper introduces a sophisticated approach for identifying and categorizing broken rotor bars in direct torque-controlled (DTC) induction motors. DTC is implemented in industrial drive systems as a suitable control method to preserve torque control performance, which sometimes shows its impact on fault-representing frequencies. This is because...

The detection of faults during an operational process constitutes a crucial objective within the framework of developing a control system to monitor the structure of industrial mechanisms. Even minor faults can give rise to significant consequences that require swift resolution. This research investigates the impact of overtension in the tooth belt...

Bearing failures in electrical machines pose significant challenges, attracting attention in diagnostic research. The widespread adoption of variable-speed drives across various motor applications has increased the effects of bearing currents, necessitating thorough exploration in both academic and industrial contexts. The paper contributes valuabl...

This study introduces an innovative approach to diagnostics, employing a unique combination of techniques including a stratified group K-fold cross-validation method and a sparse stacked autoencoder (SSAE) alongside LightGBM. By examining signatures derived from motor current, voltage, speed, and torque, the framework aims to effectively detect and...

Servomotors have found widespread application in many areas, such as manufacturing, robotics, automation, and others. Thus, the control of servomotors is divided into various principles and methods, leading to a high diversity of control systems. This article provides an overview of types of servomotors and their basic principles and control method...

Bearing failures in electrical machines present significant challenges, drawing attention in diagnostic research. The widespread use of variable-speed drives in various motor applications has intensified the impact of bearing currents, requiring comprehensive exploration in academic and industrial settings. This paper thoroughly investigates the is...

A Battery Energy Storage System (BESS) plays an important role in achieving energy transition and climate change mitigation, with charging management applications being a crucial topic to improve the build, design, and operation of renewable technologies. With the continuous development of Artificial Intelligence (AI), implementing accurate algorit...

The Internet of Things has emerged as one of the most important components for fault diagnostics in industrial applications. The emergence of the digital twin has further enhanced the capability to develop and implement industrial applications more easily to simulate industrial environments. This article describes an alternate method to generate da...

The reliable operation of power transmission networks depends on the timely detection and localization of faults. Fault classification and localization in electricity transmission networks can be challenging because of the complicated and dynamic nature of the system. In recent years, a variety of machine learning (ML) and deep learning algorithms...

This article explores the transformative potential of digital twin (DT) technology in the automotive sector, focusing on its applications in enhancing propulsion drive systems. DT technology, a virtual representation of physical objects, has gained momentum due to its real-time monitoring and analysis capabilities. Within the automotive industry, w...

Keywords: Electrical power systems, Support vector machines, Random Forest, Machine learning, Wavelet transform, Transmission lines fault, Electrical power quality, Short circuit, Classification of faults, Localization of faults, Decision trees, Ensemble learning, K-nearest neighbors.

Electrical machines are prone to various faults and require constant monitoring to ensure safe and dependable functioning. A potential fault in electrical machinery results in unscheduled downtime, necessitating the prompt assessment of any abnormal circumstances in rotating electrical machines. This paper provides an in-depth analysis as well as t...

Digital twins (DTs) have been implemented in various applications, including wind turbine generators (WTGs). They are used to create virtual replicas of physical turbines, which can be used to monitor and optimize their performance. By simulating the behavior of physical turbines in real time, DTs enable operators to predict potential failures and...

Due to their efficiency and control capabilities, induction motors fed with inverters have become prevalent in various industrial applications. However, ensuring the reliable operation of the motor and diagnosing faults on time are crucial for preventing unexpected failures and minimizing downtime. This paper systematically analyzes condition monit...

This research work implements an initial methodology for the assessment of Battery Energy Storage Systems (BESSs) based on Remaining Useful Lifetime (RUL), and its main contribution is the modeling and estimation of Health and Charge indicators through regression algorithms and binary classifiers during the battery’s operation. Linear Regression, R...

Additive manufacturing (AM) or 3D printing has opened up new opportunities for researchers in the field of electrical machines, as it allows for more flexibility in design and faster prototyping, which can lead to more efficient and cost-effective production. An overview of the primary AM techniques utilized for designing electrical machines is pre...

An algorithm to improve the resolution of the frequency spectrum by detecting the number of complete cycles, removing any fractional components of the signal, signal discontinuities, and interpolating the signal for fault diagnostics of electrical machines using low-power data acquisition cards is proposed in this paper. Smart sensor-based low-powe...

Nowadays, going beyond the 2D conventionally laminated structures is essential for improving the functionality of an electrical machine during the design process. Additive manufacturing (AM) offers unmatched 3D freedom for processing metal-based materials optimized for weight and cost effectiveness. Using this technology, new families of electrical...

Abstract The demand for energy is a relevant topic in the field of science and engineering, which has been discussed throughout the last years due to the challenges of climate change and environmental concerns around the world. Currently, electric vehicles (EVs) offer a source of mobility that emphasises the use of energy storage devices to reduce...

For several decades, the design and manufacture of electrical machines has been considered a technically mature area and, as a result, research and development in the area has been extremely limited, even though this is a crucial technology in the application of electrical energy. Electrical machines are used in over 80% of the world’s energy conve...

Electrical machines are prone to faults and failures and demand incessant monitoring for their confined and reliable operations. A failure in electrical machines may cause unexpected interruptions and require a timely inspection of abnormal conditions in rotating electric machines. This article aims to summarize an up-to-date overview of all types...

Industrial revolution 4.0 has enabled the advent of new technological advancements, including the introduction of information technology with physical devices. The implementation of information technology in industrial applications has helped streamline industrial processes and make them more cost-efficient. This combination of information technolo...

This paper presents a practical thermal model of a synchronous generator for high-power applications. This model couples the lumped parameter thermal network and coolant network together to utilize the impact of the coolant’s temperature rising over the machine. Furthermore, the advanced multi-planes technique provides a more precise and higher res...

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...

The issue of switched reluctance motor (SRM) torque ripple has received close attention in the last decade. One of the most promising methods for addressing the torque ripple problem is topology optimization (TO). Two main challenges of the TO method are the high computational burden and manufacturing constraints. This paper proposes a new three-st...

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...

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...

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...

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...

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...

-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...

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...

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...

The main issue of the switched reluctance motor (SRM) is its noise and vibration caused by high torque ripples on the rotor’s shaft. Many methods have been developed for improving the torque characteristic of the SRM. For example, design optimization is one of the promising approaches to the noise and vibration reduction of the SRM. Particularly, t...

-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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...