Projects / Programmes
Electric Power Converters and Controlled Drives
January 1, 2009
- December 31, 2013
| Code |
Science |
Field |
Subfield |
| 2.12.00 |
Engineering sciences and technologies |
Electric devices |
|
| 2.10.00 |
Engineering sciences and technologies |
Manufacturing technologies and systems |
|
| 2.03.00 |
Engineering sciences and technologies |
Energy engineering |
|
| Code |
Science |
Field |
| 2.02 |
Engineering and Technology |
Electrical engineering, Electronic engineering, Information engineering |
soft-magnetic composites, permanent magnets, special electrical machines, renewable energy sources, automotive industry, phase-shifting transformer, rectifier transformer, monitoring & diagnostics of electrical drives, linear induction motor, linear synchronous motor, linear electrical drives, electromagnetic field, solid-state power converters, magnetic components, EMC, microprocessor, fuel cells, active power filters, hybrid vehicles
Researchers (22)
Organisations (1)
Abstract
Challenges and related research:
Alternative energy sources (wind, solar, fuel cells...):
- New topologies and control principles in solid-state power converters (special requirements: efficiency, high dynamics, EMC)
- Fuel cells with polymer membrane
Ecology (reduced polutant emissions, energy saving)
- Solid-state power converters (special requirements: efficiency, high dynamics, EMC)
- Converters for separation of heavy metals from galvanic waste water
- Construction of high-efficient electrical machines
Hybrid and electric vehicles
- Solid-state power converters (special requirements: efficiency, high dynamics, EMC)
- Integrated starter-generator, optionally as an additional motor in HV
Transition from 14 V to 42 V supply in vehicles
- Solid-state power converters (special requirements: efficiency, high dynamics, EMC)
- Integrated starter-generator, optionally as an additional motor in HV
Soft magnetic composites, permanent magnets
- Integrated starter-generator, optionally as an additional motor in HV
- Other special electrical machines
Biomedicine and health
- Solid-state power converters (special requirements: efficiency, high dynamics, EMC) for electroporation of cells (i.e. electrochemoterapy, genetic ingeneering)
Electromagnetic compatibility (EMC)
- Solid-state power converters (special requirements: efficiency, high dynamics, EMC)
- New triggering methods for solid-state switches in power converters (DTC in AC motors, DCC in active power filters)
- Commutation transients in commutators: optimal commutator construction
Introduction of electric power market
- Power flow control in electric power systems: phase-shifting transformer
- Power line communication: transformers
- Power transformers: optimal solutions considering losses, local overheating, overvoltage transients and forces on windings
- Portable precision power source for calibration of electric energy meters
High-performance electrical drives
- Diagnostics of AC drives - expert system development
- High-dynamic linear motor drives (induction linear motors, synchronous linear motors)
- field modelling (finite elements)
- various control methods (v/f, FOC, ...)
- optimal current supply for linear motors (solid-state power converter)
- machine-tools, elevators, vehicles
Significance for science
Research study on possibilities for reduction of higher harmonics in the output voltage of synchronous generators that are used for power transformers testing resulted in a new approach in the field of high-voltage technology. A particular advantage of the proposed method is the use of low-voltage components, since the active filter is inserted close to the neutral point of the three-phase windings of the generator. A new control method that enables noise reduction and overall system efficiency increase for switched reluctance generators (SRG) was developed. This is of great importance when SRG is used in wind power stations and mobile applications. The study of the hybrid filter has been designed as a feasibility study of a compact filter for DC power supply systems, which ended with in-depth review of the two most suitable topologies and with three different prototypes build. The proposed solution increases the filter attenuation in the low-frequency range for 15 dB by reducing the energy imbalance that occurs in power flow between the voltage source and the load at high dynamics. For a leading manufacturer of industrial current and voltage meters MBS-AG (Germany), we carried out R&D on a prototype of precision current source for calibration of compensated current meters. It is based on the performance of the hybrid amplifier, which successfully combines the features (efficiency and low distortion) of commercially available linear power amplifier and specifically developed switching power converter - amplifier. Due to high requirements in terms of achieving the accuracy and repeatability of measurements, a special attention was paid to the innovative design of the clamping joke. Based on the theoretical study of usability and the development of the manufacturing process using soft magnetic composite materials, we have set a new milestone in the creation of three-dimensional structures as building blocks of electrical machines. Based on the finite element analysis, we designed and optimized the structure of an electric machine with three-dimensionally guided magnetic flux. Within the research of soft magnetic composite materials we developed a mathematical hysteresis model which allows us to better understand the electromagnetic phenomena at both microscopic as well as macroscopic level. Influence of manufacturing imperfections in the process of mass production of permanent magnet synchronous motors on the level of cogging torque was investigated and a new approach for determination of additional harmonic components in torque spectrum which are not present in the case of a perfect manufactured motor was developed and proposed. This enables the precise definition of tolerances for permanent magnets' anomalies so that the amount of motors exceeding the required cogging torque is successfully minimized. Research in the field of rotating electrical machines diagnostics have resulted in new methods of early detection of faults, which enable automated online supervision during the lifetime period of machine operation. For synchronous generators a precise analysis of short circuits in excitation windings was carried out, whereas in case of induction motors we focused on rotor cage faults, which are difficult to detect at an early stage of propagation, especially in sophisticated closed loop drives. To enable a detailed insight in the energy capacity of the planned small hydropower plant we developed an innovative computer model. It takes into account hydrological data, technical characteristics, optimization algorithm for water-flow distribution between two turbines and finally restrictions imposed in water-flow utilization in order to ensure a modified environmental flow, or in an extreme case, standstill at the time of high waters. The model enables the determination of optimal area of the hydro power potential, and consequently the optimal plant capacity.
Significance for the country
The results of the research programme group are also prototypes of new devices, new control methods for devices in the field of mechatronics, improvements of manufacturing processes and implementation studies. Most of the work was done in collaboration with Slovenian companies, which have the objective to maintain or to improve their position in the global market. Here, in particular, companies supplying demanding assemblies for the automotive industry are to be exposed. In the cooperation with Slovenian industry, we designed and developed the tools for serial production of electric machine with three-dimensional guided magnetic flux. These tools enable the production of electrical machines with very high torque density and with miniaturization of its overall size. During the production of soft magnetic composite prototype samples, we used our own raw materials as well as those that are commercially available. Electric machines based on soft magnetic composite material are easier to manufacture and material consumption is lower compared to the classical production. So developed and manufactured electric machine prototypes are brought already to the marketing stages at the Slovenian company Kolektor. The proposed approach for elimination of higher harmonics in the output voltage of synchronous generators has been developed in collaboration with the key producer of power transformers in Slovenia. Based on promising experimental results, the introduction of the solution into company's production process would represent a significant competitive advantage in the global market. Our research work in the field of soft-magnetic material measurements resulted in an improved measuring process that was crucial for our industrial partner to preserve and to acquire new clients at home and abroad. In the area of power transformers, we have developed a new transformer circuit model allowing the determination of surge voltage distribution along the windings. On the basis of the model, the determination of the safety features of the transformer against harmful surges (lightning and switching maneuvers) is enabled. Thus, the protection of power transformer is more reliable and financially more convenient. New approach to cogging torque analysis is fully used by Slovenian producer of permanent magnet synchronous motors for automotive industry. Research results have increased the quality of mass-produced motors and reduced the percentage of samples which did not fulfill the stringent demands of the market. Developed diagnostic systems for on-line condition monitoring of synchronous generators and induction motor drives are installed in several thermal and hydro power plants and supervise their operational states in order to prevent unexpected faults during their life time, thus increasing their reliability. In the past hydro power potential of Slovenian watercourses with ultra-low heads were not exploited for electrical energy production due to insufficient profitability. Research results confirm that by using appropriate modern technology (Archimedes screw and inverter controlled induction generator) such renewable energy potential could be interesting for potential investors.
Most important scientific results
Annual report
2009,
2010,
2011,
2012,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2009,
2010,
2011,
2012,
final report,
complete report on dLib.si
