The Laboratory of Electrical Drives Technology at the Department of Electrical Engineering has participated in various research projects, some of which are here presented in brief.
High-speed electrical machines
The research on high-speed electric machines has produced a number of prototype applications and has now also generated significant entrepreneurship. The Switch Electrical Machines (formerly Rotatek), a part of The Switch, manufactures high-speed electrical motors based on our innovations. One dissertation is in progress on the subject.
Control of torque vibrations in electrically driven machine systems (SaMeKo)
Simulation methods to model the vibrations in complex electrically driven machine systems are developed in collaboration with Metso, ABB, the Finnish Funding Agency for Technology and Innovation (TEKES), and LUT. The topic is multidisciplinary and extremely challenging; the power electronic converter, electric motor, control algorithms and mechanical systems have to be simulated simultaneously in a coupled electromechanical simulation model.
Inverter Supply Unit (ISU)
The aim of the Inverter Supply Unit (ISU) project is to develop a power electronic converter for connecting electric motor drives to the grid in such a way that the factors disturbing the voltage quality in conventional drives can be almost completely eliminated. In the future, an ISU can be applied to multiple targets, such as wind power plants and local energy generation in isolated areas. One dissertation has been published on the subject and another one is in progress. The project is carried out in collaboration with ABB, which has already commercialised some of the control methods developed at LUT.
Permanent magnet synchronous machines (PMSM) and drives
The cooperation with ABB continues with the development of new permanent magnet synchronous machines and their control algorithms. This will enable for instance a gearless, direct drive of paper machines (see the ABB ACS 600 catalogue). The development of PMSMs is employing a number of post-graduate students at the Laboratory. By this project, the Laboratory of Electrical Drives Technology contributes to creating new motor control methods.
Development of synchronous motor drives in cooperation with ABB
This project is among the largest projects of the Laboratory. Five dissertations and numerous other theses and papers have been published within the project. Further, a new industrial product has been developed for ABB (ACS6000SD). The key control algorithms were developed in the Laboratory of Electrical Drives Technology.
Energy efficiency of induction motors
Electric motors consume most of the electricity needed in the industry. Therefore, the efficiency of the electric motors is a major environmental factor. The project “Energy efficiency of induction motors” was launched in the early 1990s. First, the losses of a 4 kW induction motor were reduced to half. While at the beginning of the project the efficiency of a commercial 4 kW induction motor was 85.5 %, the efficiency of the new prototype reached 91 %. Impressed by these results, Motiva (an impartial service organisation promoting a market for renewable energy sources and efficient energy use) arranged an international competition for the manufacturers of electric machines to improve the efficiency of the motors. The machines submitted to the efficiency competition were measured in the Laboratory of Electrical Drives Technology at LUT. The winners were two machines manufactured by ABB. The topic has been investigated within the EU, and the Laboratory of Electrical Drives has had a chance to influence the new efficiency standards set for induction motors in industry.
Control of switched reluctance (SR) motors in car industry
The project was carried out in cooperation with Robert Bosch GmBH. A switched reluctance (SR) motor is economical to produce, yet it is difficult to achieve smooth torque production by control electronics. Smooth torque is needed for example in the power steering of a car to prevent the steering wheel from vibrating.
Development of induction heating for industrial use
The research project “Teollisuuden induktiokuumennusjärjestelmät” (Induction heating systems for industrial use) was launched at Lappeenranta University of Technology in autumn 1996. The key target of the project has been to enhance the Finnish know-how on induction heating and thus to promote the use of induction heating in industrial applications.
The targets of the project were to increase the energy efficiency, to improve the performance of an induction heating power source and to develop the control of the induction heating process. In the project, a transistor-based controllable induction heating power source was developed and the control properties of a commercial induction heating power source were improved. Further, a survey of the use of induction heating in the Finnish industry was carried out.