Five phases and no permanent magnets. Scientists from GdańskTech created a new type of generator | Faculty of Electrical and Control Engineering at the Gdańsk University of Technology

A team of scientists from the Faculty of Electrical and Control Engineering, led by PhD Roland Ryndzionek composed of: PhD Krzysztof Blecharz, PhD Filip Kutt, PhD Grzegorz Kostro and PhD Michał Michna, developed a prototype of a new five-phase generator. It is a multi-phase induction generator for use in a wind, water or gas power plant. It can also be used by the army and can be used, for example, in tanks or armored cars. Innovative in the prototype is the use of a five-phase control winding.

- Generators with a three-phase control winding are widely available on the market, but there are no machines with a five-phase control winding. We are pioneers in this field - emphasizes Grzegorz Kostro - So far, such a prototype has not been developed, because the problem is to develop such a control winding that will not be coupled with the power winding directly, but through a shorted rotor winding, and to attach a dedicated control system to it. We did it.

AC machines, such as a generator, need a rotating magnetic field to function properly. The condition for the generation of this type of magnetic field in a stationary system is an appropriate distribution of the windings in the space (where there are at least 2 phases). Loss of power in the case of two-phase or three-phase windings in one of the phases immediately disqualifies the operation of the entire system, as it is then impossible to obtain a rotating magnetic field. - Five phases in the control winding mean that the generator can continue to work when one of the winding phases is damaged, or when one branch of the inverter is damaged. This results in increased generator reliability and ensures greater safety, adds Filip Kutt.

- Our generator, thanks to five phases, will still work in an emergency, with a slightly reduced efficiency, at the level of 10-15 percent, but still so much that the device that it powers would not stop working until the defect is repaired - explains Michał Michna - It should be noted that we are the only team that undertook the construction of such a prototype in Poland. We have also not met with such research in the world.

The team has already prepared a prototype of a five-phase brush generator and is currently working on a brushless model.

Reliable and eco-friendly
- Currently, we are facing an energy crisis, and one of the possibilities of diversifying energy sources is obtaining it as often as possible from ecological sources, for example through wind farms. Our generator not only gives a greater guarantee of reliability, but is also ecological. We do not use permanent magnets, commonly used in other devices of this type, for its construction. The problem is obtaining them on a mass scale, because the magnet market has been completely monopolized by China. Thanks to our idea, we can become independent from Asian markets. Devices without permanent magnets are extremely desirable, so we are sure that our generator will arouse interest, especially on the European market, says Roland Ryndzionek.

- To take full advantage of the properties and capabilities of the developed model of a multi-phase generator, it is necessary to use a dedicated power electronic converter solution, which is not available on the market. The solution proposed by our team is modern not only in terms of generator design, but also in terms of the applied topology of the bidirectional voltage converter. The internal configuration of the converter uses DC voltage intermediate circuits to connect a standard three-phase inverter from the supply network side and a five-phase inverter from the generator rotor side. The converter model developed and constructed in this way enables the implementation of the latest solutions of generator power control algorithms in normal operation and in the event of failure of the five-phase inverter transistors. Works in the field of applied power electronics solutions and the development of control systems are an additional challenge for us - emphasizes Krzysztof Blecharz.

The solution proposed by scientists from GUT is modern not only in terms of the generator design, but also in terms of the applied topology of the bidirectional voltage converter. The internal configuration of the converter uses DC voltage intermediate circuits to connect a standard three-phase inverter from the supply network side and a five-phase inverter from the generator rotor side. The converter model developed and constructed in this way enables the implementation of the latest solutions of generator power control algorithms in normal operation and in the event of failure of the five-phase inverter transistors. Works in the field of power electronics solutions and the development of