ELECTRICAL MACHINE GROUP
Electrical Machine Group (EMG) is a research group within the Department of Electrical Power Engineering and Mechatronics in Tallinn University of Technology (TTÜ), Estonia, specialized in electrical machines and drives. The group carries out R&D as well as study programs in the fields of interest and consists of various specialists of this scientific area.
Main research fields
The research in the field has been carried out during more than 10 years. R&D has been carried out mainly for low and medium power radial flux machines (1-150 kVA). Both inner and outer rotor construction using different magnetic materials (NdFeB, SmCo, ferrite) have been investigated. Knowhow of this research field has been utilized in the development a 3 MVA ring-shaped generator used in wind turbines. Further studies of this field are also dedicated to the investigation of high speed (6000 rpm) permanent magnet machines that can be used as generators or motors in Unmanned Aerial Vehicles (UAVs).
The investigation towards the prediction and diagnosis of different electrical machine faults is been carried out in the EMG. Mainly induction machine rotor and stator faults (broken bars, eccentricity, stator short-circuits) have been the subject of the study. Some attention have been paid also to the diagnostics of faults in synchronous machines.
Along with the more traditional diagnostic approaches, several novel and emerging technologies in the field are being investigated. Some of the approaches involved are:
- Usage of mobile phones and other similar devices for simple pre-diagnostics of electrical machines,
- Usage of cloud computing environments and IoT (Internet of Things) solutions for diagnostics in the view of Industry 4.0,
- Implementation of inverse problem theory in the field of electrical machine diagnostics to further enhance the early stage recognition of the faults and improve the overall precision of detection.
The aim of the research is to design materials with comparable or even better magnetic properties to materials commercially available today but with reduced cost and impact on the environment. The main topics of the research include development permanent magnet alloys with controlled composition and microstructure; development of magnets with improved performance at high operation temperatures (up to 150°C); prototyping of several new grades of permanent magnets with reduced content of Nd and Dy providing alternatives to those of manufactured by conventional compositions and methods.
Research of novel permanent magnet materials is being carried out in cooperation with the department of material technology in TTÜ and several industrial partners. The main task for EMG in this research is the design of new materials and grades for wind generators, assessment and specification of the material properties etc.
In this research building of novel optimization procedure, which accounts for the whole life-cycle of the motor-drive and includes the different phases of the ecodesign and their environmental impacts is proposed. Such a procedure will result in life-cycle energy and resource efficient designs and contribute to the protection of environment. The research itself includes building of different simulation tools, survey among the stakeholders and extensive use of distributed computation to achieve a sustainable design of a selected range and type of motor-drives. The practical implementation of the developed design and optimization methodology will be realized on 10 kVA permanent magnet assisted synchronous reluctance machine.
Additive manufacturing, also known as 3D printing, is opening up new ground for innovations in low-volume production due to faster and cheaper prototyping, reduced lead time and shorter supply chains. It is a relatively new technology, which enables the tool-free production of components and entire assemblies directly from a CAD file. Today, the technology is still not widely used in industrial production, but it is gaining more and more popularity. There is a need for principles how to design electrical machine so that it would be suitable for 3D printing.
Project target is an electrical machines for wind turbine applications. Wind energy is the most cost-effective climate change mitigation technology. The main goal of the project is to perform Life Cycle Analysis to determinate a quantity of raw materials of different electrical machines used for wind applications. The lifecycle assessment implies important procedures that can help reduce electrical machine impact on the environment, thus being an instrument for assessment of the influence exerted by particular products on the environment – from cradle to grave – beginning with acquisition of the materials followed by manufacturing, transporting, marketing, use and recycling.
In hand with optimized predictive maintenance and condition monitoring approaches, it helps to lower the price of renewable energy generation, empowering the further alternative energy use instead of burning fossil fuels.
Electrical Machine Group is located in the TTÜ campus in Tallinn, Estonia. There are a fully equipped electrical machines study laboratory and scientific laboratory for the use of the group. Scientific laboratory of electrical machines is in a continuous development. Currently, electrical machines in the power range of 45-50 kW can be tested in the facilities. Thermal conditions of the machines can also be monitored and cooling tests of wind generators can be performed using a wind tunnel. Experimental assessment of losses and thermal processes of electrical machines are also possible to perform. There is a full setup for different electrical machines diagnostic tests with a large number of same series machines as well as converters and possibility of inflicting almost any electromechanic fault. All of the measurements can be recorded simultaneously and control algorithms can be tested using special build converters and real time target machine.