Operation Of Permanent Magnet Synchronous Generator Research Articles

Application of electromagnetic continuous variable transmission in hydraulic turbines to increase stability of an off-grid power system

In the context of climate change, today's adoption of renewable energy sources in isolated power systems is becoming an increasingly more significant issue. Micro-hydro power plants are emerging as a mature balancing technology and a great alternative to large hydropower plants as they do not encounter population displacement and many environmental problems. It is worth noting that hydroelectric power plants combined with various sources require improvement in control laws and algorithms. Strong disturbing impacts, namely transient processes, in an isolated electric power system cause an appreciable decrease in dynamic stability. This paper presents research conducted to ensure synchronous parallel operation of permanent-magnet generators used in micro-hydroelectric power plants in an isolated power system with a controllable flexible coupling between turbine and generator. The importance of this study lies in the issue of electromechanical compatibility to be achieved in parallel operation of generators that have different parameters of time constant of mechanical inertia of rotors of electrical machines. This paper provides an overview of possible solutions to the identified problem. A concept based on a controllable flexible coupling between generator and turbine is proposed as a promising avenue to solve this problem. The mathematical models are presented along with the laws and algorithms developed for automatic control of the generator speed. Oscillograms of simulation and physical modeling presented in the final part of the paper show parallel operation of permanent-magnet synchronous generators in an isolated electric power system for various electrical distances of three-phase short circuit points.

Methods to reduce cogging torque of permanent magnet synchronous generator used in wind power plants

This paper presents five latest methods and explains the last- new one with intention to reduce the cogging torque of permanent magnet synchronous generators (PMSG). The PMSGs are widely used in wind power plants (WPP) as one of the renewable power generation. One of the international goals is to expand the use of renewable energy sources. The main disadvantage of PMSG is the influence of magnetic interaction between the magnets and the teeth on the operation of PMSG, thus many scientists have been researching the possibilities to reduce the cogging torque. The magnetic field modelling software is used to obtain the values of PMSG cogging torque. The calculations in this software are based on finite element analysis. A methodology is created to obtain the 3D results from the 2D modelled magnetic field. The achieved results allowed to submit a patent. The new proposed method is researched allowing to receive the first results of PMSG optimal design, thus expanding the lower boundary of operating wind speed for WPP. DOI: http://dx.doi.org/10.5755/j01.eie.23.1.12714

Unity Power Factor Control of a Direct-Driven Permanent Magnet Synchronous Wind-Power Generator Based on Three-Level Converter

Direct-driven permanent magnet synchronous generator (PMSG) has become an important research subject besides the double-fed induction generator. With the increasing of unit capacity, the study of topology of high power converters based on multi-level converter is attracting more and more attention. The study of vector control of the direct-driven permanent magnet synchronous wind turbines based on three-level converter is carried out in this paper. Based on the maximum wind-energy capture control of the PMSG, the unity power factor operation of PMSG is realized by controlling the d-axis current to zero in the generator-side converter. A detailed comparative study of two-level system and three-level system is conducted. The simulation results verify the validity of this algorithm.