Z. Raud - Academia.edu (original) (raw)
Papers by Z. Raud
Modelling and simulation provide effective way to acquire engineering experience. An active appro... more Modelling and simulation provide effective way to acquire engineering experience. An active approach to modelling and simulation proposed in the paper involves, beside the compulsory part directed by the traditional step-by-step instructions, the new optional part basing on the human's habits to design thus stimulating the efforts towards success in active learning. Computer exercises as a part of engineering curriculum incorporate a set of effective activities. In addition to the knowledge acquired in theoretical training, the described educational arrangement helps to develop problem solutions, computation skills, and experimentation performance along with enhancement of practical experience and qualification.
This paper describes the design considerations of an experimental setup for research and explorin... more This paper describes the design considerations of an experimental setup for research and exploring the drives of batteryfed electric vehicles. Effective setup composition and its components are discussed. With experimental setup described in this paper, durability and functional tests can be procured to the customers. Multiple experiments are performed in the form of steady-state system exploring, acceleration programs, multi-step tests (speed control, torque control), load collectives or close-to-reality driving tests (driving simulation). Main focus of the functional testing is on the measurements of power and energy efficiency and investigations in driving simulation mode, which are used for application purposes. In order to enable the examination of the drive trains beyond standard modes of operation, different other parameters can be studied also.
Renewable Energy and Power Quality Journal, 2021
A neural network-based control system is offered, which ensures high quality blended braking of t... more A neural network-based control system is offered, which ensures high quality blended braking of the green energy vehicles in both the intensive and the gradual deceleration scenarios, with energy recovery at the changing road pavement. In this study, a neural network controller provides the torque gradient control without a tire model resulting in returning maximal energy to the hybrid energy source during the braking process. To meet the conflicting requirements of different braking modes and road surfaces, an allocation algorithm determines how to distribute the driver’s torque request between the friction and electrical brakes. Simulation demonstrates effectiveness of the proposed braking system. Model states and inputs are used as a guidance to learn a coupled two-layer neural network capable to capture various dynamic behaviours that could not be included in the simplified physics-based model. An experimental part of the research proves the model and simulation validity.
Modelling, Identification, and Control, 2010
The paper introduces an effective toolbox to design and study mechatronic systems suitable for en... more The paper introduces an effective toolbox to design and study mechatronic systems suitable for engineers, researchers, and students. The described package eDrive includes the database of motors, power converters, gears and other mechanical components, the object-oriented simulation software, the signal generation module, the controller design module, as well as the suitable visual interface. The system provides dc and ac mechatronic systems development, tuning, and investigation with current, speed, and position adjustment in open loop and closed-loop modes.
2014 55th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON), 2014
A remote environment proposed in the paper enables the study electrical drives via the Web. The a... more A remote environment proposed in the paper enables the study electrical drives via the Web. The active learning concept of the distance education and the set of Internet-based laboratory works open the possibility to learn Basic and Advanced Courses of Electrical Drive providing a lot of benefits for both the learners and the faculty. The remote labs for the bachelor and master students are presented. Reporting and assessment procedures along with the analysis of the results obtained are discussed.
Power losses of electric drives depend to a large extent on the switching frequency, currents, an... more Power losses of electric drives depend to a large extent on the switching frequency, currents, and supply voltage of the power semiconductor inverter. As these three parameters affect the motor torque and speed, they must be considered in the synthesis of the algorithms provided in the inverter adjustment. This paper presents the simulation and experimental study on a space vector modulation (SVM) inverter that supplies the alternating current (ac) electric drive with low switching losses. A new toolkit to explore different modulation techniques is described. Some methods of the load-dependent control over ac electric drive inverters are examined through simulation and experimentation. The benefits of the new discontinuous SVM algorithms upon the well-known control techniques are discussed.
Despite of popularity and multiple attractive features, a single‐phase induction motor (SPIM) sti... more Despite of popularity and multiple attractive features, a single‐phase induction motor (SPIM) still not used in the vehicular applications because of starting problems, low‐ speed operation complexity, and other control drawbacks. The aim of this work is to realize the stable torque‐speed characteristics of the low‐power capacitor‐run SPIM in wide range of speeds. The SPIM behavior at the variable‐ frequency operation was explored in the paper and some methods were proposed to improve the motor characteristics. To overcome the prominent shortcomings and to meet the vehicle requirements, some novelties were designed in the SPIM control arrangements.
The paper presents a study of the concept mapping informational technology for instruction in Ele... more The paper presents a study of the concept mapping informational technology for instruction in Electronics. As the first step of the ontology design, the authors have developed an effective descriptive model in the form of educational thesauri. Then, to represent the knowledge structure for meaningful education, concept mapping was introduced as graphic ontology for Electronics. Concept maps help students to see what they acquired from the class and support in making connections between new and prior concepts. This technique reinforces knowledge integration by providing students with an activity that promotes such integration. Also, it supports assessment procedures providing an explicit and overt representation of learners' knowledge, informative, and reflective feedbacks tailored to learners' individual characteristics and needs.
ABSTRACT Abstract – The paper explores the responses of battery e-vehicle drives to the changeabl... more ABSTRACT Abstract – The paper explores the responses of battery e-vehicle drives to the changeable control signals. The drive behavior was studied in the laboratory test bench. The set of test cycles prepared in the frame of the ABB control arrangement was applied to the system evaluation and assessment. The study describes the major driving modes, such as the constant-speed cruising, speeding up and breaking, typical parking regimes, uphill and downhill motion, travelling up the gradient, and taking a turn. The proposed methodology helps to measure the static and dynamic quality of the propulsion and to recommend approaches for the regulator tuning, control looping, sensor allocation, and feedback arrangements.
Education Research International, 2015
The paper describes how to employ the concept mapping technology in engineering education in the ... more The paper describes how to employ the concept mapping technology in engineering education in the field of Electronics. The overall knowledge domain ontology in the field is shown. It is underlined that the concept maps serve as a suitable tool to support instructors in promoting students’ comprehension of the studying material and in improving their understanding of new concepts. Introduction of an original educational thesaurus is proposed. Such a thesaurus helps learners to see what they have acquired from the lessons. It supports them in making connections between new and prior concepts and reinforces knowledge integration by such a promotion. The developed concept maps are regarded as a valuable instrument of many assessment procedures. They represent learners’ knowledge providing informative and reflective feedbacks tailored to learners’ personal styles and requests.
2014 IEEE 23rd International Symposium on Industrial Electronics (ISIE), 2014
ABSTRACT The analysis of the promoted innovative setups and practices of educational systems reve... more ABSTRACT The analysis of the promoted innovative setups and practices of educational systems revealed the necessity to develop an active learning approach. On-lecture assessment methods developed in the active learning context and introduced into Electronics, Power Electronics, and Electrical Drives promote ultimately students' progress increasing the quality of learning. To motivate students, specific self-assessment modules were prepared in the scope of the institutional learning content management system. They encourage the students to acquire the methods, skills, and experience related to the real power electronics and drives equipment in a manner that is very close to the way they are being used in industry. This approach helps the teachers to interact with students and to utilize their practical experience and knowledge to improve course applicability and attraction.
This paper gives an overview of an advanced course of power electronics for master students by in... more This paper gives an overview of an advanced course of power electronics for master students by introducing new laboratory equipment to be used in the study process. In addition, this equipment can be used in student research projects and training courses.
Different simulation instruments to study power electronics of motor drive are described. For eac... more Different simulation instruments to study power electronics of motor drive are described. For each educational level, the specific approach and soft tool is proposed. The simulation instruments have been examined and compared in learning environment of Tallinn Technical University.
The paper presents the concept of the distance laboratory developed in Tallinn University of Tech... more The paper presents the concept of the distance laboratory developed in Tallinn University of Technology. Advantages of e-learning, the proposed architecture, association with traditional learning, and description of a laboratory work are given.
The paper presents the topology and functioning of the model-based laboratory system to study the... more The paper presents the topology and functioning of the model-based laboratory system to study the power electronic converters structure and execution and to evaluate their different duty modes of operation. Detailed description of the models of ac/dc, dc/ac, ac/ac and dc/dc virtual power converters and their auxiliary circuits are given. Learning possibilities and restrictions of the described software are analysed.
The paper outlines a project-based collaborative learning methodology developed for graduate cour... more The paper outlines a project-based collaborative learning methodology developed for graduate courses on Electrical Drives and Power Electronics in Tallinn University of Technology. An underlying principle of the described environment is the coursework arrangement directed to designing optimal application-specific drives with power electronic converters based on the active learning approach. The role of advanced computer-aided design tools is also identified and shown. To illustrate the effectiveness of this method, the industry-relevant course projects performed in the curriculum are presented in detail. An important result found is that all students acquired knowledge and skills to design more complex and sophisticated electromechanical systems.
Basing on a study of promoted innovative set-ups and practices in the industrial European SMEs, t... more Basing on a study of promoted innovative set-ups and practices in the industrial European SMEs, this paper describes a novel approach to curricula organisation that aims to facilitate and improve the quality and efficiency of in-service training, on-the-job training, and undergoing training provided in a workplace environment of electronic engineering. The purpose is to ground an educational model suitable for planning optimal training trajectories in the framework of the curricula arrangement in the context of SMEs. The focus concerns reevaluation of the curriculum design along with the strengthen role of e-learning basing on the conceptual models and structures.
ABSTRACT Ì Based on a study of promoted innovative set-ups and practices of European enterprises,... more ABSTRACT Ì Based on a study of promoted innovative set-ups and practices of European enterprises, this paper describes a novel approach to curricula organisation that aims to facilitate and improve the quality and efficiency of in-service training, on-the- job training, and undergoing training provided in a workplace environment of power electronic engineering. The purpose is to ground an educational model suitable for planning optimal training trajectories in the industry context. Effective instruments are given to build the most appropriate professional thesauri for the company staff and to find an institution capable of providing training in such thesauri. Unlike the traditional environment, the proposed flexible curriculum has an exclusively dynamic nature. Any time when the professional level is raised, the curriculum may be changed simultaneously along with its background conceptual matrix. Thus, new disciplines are introduced, the contents of the corresponding disciplines refreshed, and the borders between the disciplines shifted fluently. This promotes designing the teaching modules in highly interdisciplinary areas and in the areas with specific needs.
ABSTRACT Power losses of the motor drive depend to a large extent on the switching frequency, cur... more ABSTRACT Power losses of the motor drive depend to a large extent on the switching frequency, currents, and supply voltage of the power inverter. As these three parameters affect the motor torque and speed, they must be considered in the synthesis of the inverter adjustment algorithms. In this paper, a new toolbox for exploring the modulation techniques is described. Some methods of the load-dependent control of motor drive inverters are discussed and examined by simulation and experimentation. The developed control systems improve economic indicators of induction motor drives.
Modelling and simulation provide effective way to acquire engineering experience. An active appro... more Modelling and simulation provide effective way to acquire engineering experience. An active approach to modelling and simulation proposed in the paper involves, beside the compulsory part directed by the traditional step-by-step instructions, the new optional part basing on the human's habits to design thus stimulating the efforts towards success in active learning. Computer exercises as a part of engineering curriculum incorporate a set of effective activities. In addition to the knowledge acquired in theoretical training, the described educational arrangement helps to develop problem solutions, computation skills, and experimentation performance along with enhancement of practical experience and qualification.
This paper describes the design considerations of an experimental setup for research and explorin... more This paper describes the design considerations of an experimental setup for research and exploring the drives of batteryfed electric vehicles. Effective setup composition and its components are discussed. With experimental setup described in this paper, durability and functional tests can be procured to the customers. Multiple experiments are performed in the form of steady-state system exploring, acceleration programs, multi-step tests (speed control, torque control), load collectives or close-to-reality driving tests (driving simulation). Main focus of the functional testing is on the measurements of power and energy efficiency and investigations in driving simulation mode, which are used for application purposes. In order to enable the examination of the drive trains beyond standard modes of operation, different other parameters can be studied also.
Renewable Energy and Power Quality Journal, 2021
A neural network-based control system is offered, which ensures high quality blended braking of t... more A neural network-based control system is offered, which ensures high quality blended braking of the green energy vehicles in both the intensive and the gradual deceleration scenarios, with energy recovery at the changing road pavement. In this study, a neural network controller provides the torque gradient control without a tire model resulting in returning maximal energy to the hybrid energy source during the braking process. To meet the conflicting requirements of different braking modes and road surfaces, an allocation algorithm determines how to distribute the driver’s torque request between the friction and electrical brakes. Simulation demonstrates effectiveness of the proposed braking system. Model states and inputs are used as a guidance to learn a coupled two-layer neural network capable to capture various dynamic behaviours that could not be included in the simplified physics-based model. An experimental part of the research proves the model and simulation validity.
Modelling, Identification, and Control, 2010
The paper introduces an effective toolbox to design and study mechatronic systems suitable for en... more The paper introduces an effective toolbox to design and study mechatronic systems suitable for engineers, researchers, and students. The described package eDrive includes the database of motors, power converters, gears and other mechanical components, the object-oriented simulation software, the signal generation module, the controller design module, as well as the suitable visual interface. The system provides dc and ac mechatronic systems development, tuning, and investigation with current, speed, and position adjustment in open loop and closed-loop modes.
2014 55th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON), 2014
A remote environment proposed in the paper enables the study electrical drives via the Web. The a... more A remote environment proposed in the paper enables the study electrical drives via the Web. The active learning concept of the distance education and the set of Internet-based laboratory works open the possibility to learn Basic and Advanced Courses of Electrical Drive providing a lot of benefits for both the learners and the faculty. The remote labs for the bachelor and master students are presented. Reporting and assessment procedures along with the analysis of the results obtained are discussed.
Power losses of electric drives depend to a large extent on the switching frequency, currents, an... more Power losses of electric drives depend to a large extent on the switching frequency, currents, and supply voltage of the power semiconductor inverter. As these three parameters affect the motor torque and speed, they must be considered in the synthesis of the algorithms provided in the inverter adjustment. This paper presents the simulation and experimental study on a space vector modulation (SVM) inverter that supplies the alternating current (ac) electric drive with low switching losses. A new toolkit to explore different modulation techniques is described. Some methods of the load-dependent control over ac electric drive inverters are examined through simulation and experimentation. The benefits of the new discontinuous SVM algorithms upon the well-known control techniques are discussed.
Despite of popularity and multiple attractive features, a single‐phase induction motor (SPIM) sti... more Despite of popularity and multiple attractive features, a single‐phase induction motor (SPIM) still not used in the vehicular applications because of starting problems, low‐ speed operation complexity, and other control drawbacks. The aim of this work is to realize the stable torque‐speed characteristics of the low‐power capacitor‐run SPIM in wide range of speeds. The SPIM behavior at the variable‐ frequency operation was explored in the paper and some methods were proposed to improve the motor characteristics. To overcome the prominent shortcomings and to meet the vehicle requirements, some novelties were designed in the SPIM control arrangements.
The paper presents a study of the concept mapping informational technology for instruction in Ele... more The paper presents a study of the concept mapping informational technology for instruction in Electronics. As the first step of the ontology design, the authors have developed an effective descriptive model in the form of educational thesauri. Then, to represent the knowledge structure for meaningful education, concept mapping was introduced as graphic ontology for Electronics. Concept maps help students to see what they acquired from the class and support in making connections between new and prior concepts. This technique reinforces knowledge integration by providing students with an activity that promotes such integration. Also, it supports assessment procedures providing an explicit and overt representation of learners' knowledge, informative, and reflective feedbacks tailored to learners' individual characteristics and needs.
ABSTRACT Abstract – The paper explores the responses of battery e-vehicle drives to the changeabl... more ABSTRACT Abstract – The paper explores the responses of battery e-vehicle drives to the changeable control signals. The drive behavior was studied in the laboratory test bench. The set of test cycles prepared in the frame of the ABB control arrangement was applied to the system evaluation and assessment. The study describes the major driving modes, such as the constant-speed cruising, speeding up and breaking, typical parking regimes, uphill and downhill motion, travelling up the gradient, and taking a turn. The proposed methodology helps to measure the static and dynamic quality of the propulsion and to recommend approaches for the regulator tuning, control looping, sensor allocation, and feedback arrangements.
Education Research International, 2015
The paper describes how to employ the concept mapping technology in engineering education in the ... more The paper describes how to employ the concept mapping technology in engineering education in the field of Electronics. The overall knowledge domain ontology in the field is shown. It is underlined that the concept maps serve as a suitable tool to support instructors in promoting students’ comprehension of the studying material and in improving their understanding of new concepts. Introduction of an original educational thesaurus is proposed. Such a thesaurus helps learners to see what they have acquired from the lessons. It supports them in making connections between new and prior concepts and reinforces knowledge integration by such a promotion. The developed concept maps are regarded as a valuable instrument of many assessment procedures. They represent learners’ knowledge providing informative and reflective feedbacks tailored to learners’ personal styles and requests.
2014 IEEE 23rd International Symposium on Industrial Electronics (ISIE), 2014
ABSTRACT The analysis of the promoted innovative setups and practices of educational systems reve... more ABSTRACT The analysis of the promoted innovative setups and practices of educational systems revealed the necessity to develop an active learning approach. On-lecture assessment methods developed in the active learning context and introduced into Electronics, Power Electronics, and Electrical Drives promote ultimately students' progress increasing the quality of learning. To motivate students, specific self-assessment modules were prepared in the scope of the institutional learning content management system. They encourage the students to acquire the methods, skills, and experience related to the real power electronics and drives equipment in a manner that is very close to the way they are being used in industry. This approach helps the teachers to interact with students and to utilize their practical experience and knowledge to improve course applicability and attraction.
This paper gives an overview of an advanced course of power electronics for master students by in... more This paper gives an overview of an advanced course of power electronics for master students by introducing new laboratory equipment to be used in the study process. In addition, this equipment can be used in student research projects and training courses.
Different simulation instruments to study power electronics of motor drive are described. For eac... more Different simulation instruments to study power electronics of motor drive are described. For each educational level, the specific approach and soft tool is proposed. The simulation instruments have been examined and compared in learning environment of Tallinn Technical University.
The paper presents the concept of the distance laboratory developed in Tallinn University of Tech... more The paper presents the concept of the distance laboratory developed in Tallinn University of Technology. Advantages of e-learning, the proposed architecture, association with traditional learning, and description of a laboratory work are given.
The paper presents the topology and functioning of the model-based laboratory system to study the... more The paper presents the topology and functioning of the model-based laboratory system to study the power electronic converters structure and execution and to evaluate their different duty modes of operation. Detailed description of the models of ac/dc, dc/ac, ac/ac and dc/dc virtual power converters and their auxiliary circuits are given. Learning possibilities and restrictions of the described software are analysed.
The paper outlines a project-based collaborative learning methodology developed for graduate cour... more The paper outlines a project-based collaborative learning methodology developed for graduate courses on Electrical Drives and Power Electronics in Tallinn University of Technology. An underlying principle of the described environment is the coursework arrangement directed to designing optimal application-specific drives with power electronic converters based on the active learning approach. The role of advanced computer-aided design tools is also identified and shown. To illustrate the effectiveness of this method, the industry-relevant course projects performed in the curriculum are presented in detail. An important result found is that all students acquired knowledge and skills to design more complex and sophisticated electromechanical systems.
Basing on a study of promoted innovative set-ups and practices in the industrial European SMEs, t... more Basing on a study of promoted innovative set-ups and practices in the industrial European SMEs, this paper describes a novel approach to curricula organisation that aims to facilitate and improve the quality and efficiency of in-service training, on-the-job training, and undergoing training provided in a workplace environment of electronic engineering. The purpose is to ground an educational model suitable for planning optimal training trajectories in the framework of the curricula arrangement in the context of SMEs. The focus concerns reevaluation of the curriculum design along with the strengthen role of e-learning basing on the conceptual models and structures.
ABSTRACT Ì Based on a study of promoted innovative set-ups and practices of European enterprises,... more ABSTRACT Ì Based on a study of promoted innovative set-ups and practices of European enterprises, this paper describes a novel approach to curricula organisation that aims to facilitate and improve the quality and efficiency of in-service training, on-the- job training, and undergoing training provided in a workplace environment of power electronic engineering. The purpose is to ground an educational model suitable for planning optimal training trajectories in the industry context. Effective instruments are given to build the most appropriate professional thesauri for the company staff and to find an institution capable of providing training in such thesauri. Unlike the traditional environment, the proposed flexible curriculum has an exclusively dynamic nature. Any time when the professional level is raised, the curriculum may be changed simultaneously along with its background conceptual matrix. Thus, new disciplines are introduced, the contents of the corresponding disciplines refreshed, and the borders between the disciplines shifted fluently. This promotes designing the teaching modules in highly interdisciplinary areas and in the areas with specific needs.
ABSTRACT Power losses of the motor drive depend to a large extent on the switching frequency, cur... more ABSTRACT Power losses of the motor drive depend to a large extent on the switching frequency, currents, and supply voltage of the power inverter. As these three parameters affect the motor torque and speed, they must be considered in the synthesis of the inverter adjustment algorithms. In this paper, a new toolbox for exploring the modulation techniques is described. Some methods of the load-dependent control of motor drive inverters are discussed and examined by simulation and experimentation. The developed control systems improve economic indicators of induction motor drives.