Krzysztof Makowski

Analysis of self-excitation and performance characteristics of a single-phase self-excited induction generator by field-circuit method

Purpose – The purpose of this paper is to present analysis of an influence of rotor slots opening on self-excitation process, terminal voltage and performance characteristics of the single-phase self-excited induction generator (SPSEIG). Design/methodology/approach – The paper presents field analysis of the self-excitation problem in the SPSEIG and performance characteristics on the base of two-dimensional field-circuit model of the generator. Findings – The carried out field computations of the tested SPSEIG with closed rotor slots showed that only an initial voltage across the excitation capacitor of about nominal value (230 V) causes successful self-excitation of the generator. It was also proved that the suitable opening of the rotor slots, beside remnant flux density in the rotor core, facilitates self-excitation in the generator. Since in working applications initially charging of the capacitor to almost nominal voltage may cause a problem, therefore employment of semi-closed rotor slots in the SPSE...

Optimization of a single-phase capacitor induction motor by applying a surrogate field-circuit model

Purpose – The purpose of this paper is to present optimization of a single-phase capacitor induction motor with respect to efficiency and starting torque by using surrogate field-circuit model for steady-state. As variables, dimensions of the rotor slots and capacitor capacitance were assumed, whereas outputs were the motor performance characteristics. Searching for a motor design of maximum starting torque or maximum efficiency were objectives of the optimization. To verify design solutions, rated load and locked rotor tests of the optimized motors were performed by computer simulation which confirmed better performance parameters of the optimized motors. Design/methodology/approach – The paper presents optimization procedure of a single-phase capacitor induction motor by applying response surface methodology for surrogate 2D field-circuit model of the motor. For solving the problem a single-objective and bi-objective approach were applied. Findings – The carried out calculations showed that obtained new...

Improving performance of a single-phase self-excited induction generator by modification of an excitation winding

The paper deals with single-phase induction machine operating as a self-excited induction generator which may be used to generate electrical energy from non-conventional energy sources. Performance characteristics of the self-excited generator with capacitor connected to the both stator windings under load operating conditions are computed by field-circuit method. By changing number of turns and size of wires of the auxiliary stator winding, considerable improvement of performance characteristics of the generator were obtained with respect to no-load voltage and under load condition. Furthermore, an influence of corresponding changes in the excitation stator winding on voltage magnitude induced in excitation winding, winding currents and output power of the generator for two capacitor topology in the main stator winding have been presented. The obtained simulation results may be useful in designing the self-excited induction generator on the base of single phase capacitor induction motors. Streszczenie. Artykuł przedstawia jednofazową maszynę indukcyjną pracującą jako samowzbudny generator indukcyjny, który może być wykorzystany do wytwarzania energii elektrycznej z niekonwencjonalnych źródeł energii. Charakterystyki pracy samowzbudnego generatora indukcyjnego z kondensatorem podłączonym do obu uzwojeń stojana wyznaczone zostały za pomocą modelu polowo-obwodowego przy obciążeniu rezystancyjnym. Przez zmianę liczby zwojów i rozmiaru (średnicy) drutu uzwojenia pomocniczego stojana uzyskano znaczną poprawę charakterystyk generatora ze względu na wartość napięcia i prądu w uzwojeniu wzbudzenia generatora. Prezentowane wyniki uzyskane z symulacji mogą być wykorzystane w projektowaniu samowzbudnych generatorów indukcyjnych na bazie konstrukcji jednofazowych silników indukcyjnych. (Poprawa charakterystyk pracy samowzbudnego jednofazowego generatora indukcyjnego przez modyfikację uzwojenia wzbudzenia).

Field-circuit analysis and measurements of a single-phase self-excited induction generator

Abstract The paper deals with a single-phase induction machine operating as a stand-alone self-excited single-phase induction generator for generation of electrical energy from renewable energy sources. By changing number of turns and size of wires in the auxiliary stator winding, an improvement of performance characteristics of the generator were obtained as regards no-load and load voltage of the stator windings as well as stator winding currents of the generator. Field-circuit simulation models of the generator were developed using Flux2D software package for the generator with shunt capacitor in the main stator winding. The obtained results have been validated experimentally at the laboratory setup using the single-phase capacitor induction motor of 1.1 kW rated power and 230 V voltage as a base model of the generator.

The employment of a single-phase capacitor induction motor for stand-alone generating operation

The paper presents a two-dimensional field-circuit model of a two-winding, single-phase induction machine operating as single-phase, self-excited induction generator. The model takes remnant magnetism and magnetization characteristics of the stator and rotor core i