Six-phase Self-excited Induction Generator Research Articles

Performance analysis of stand-alone six-phase induction generator using heuristic algorithms

The paper exhibits the performance analysis of six-phase self-excited induction generator for stand-alone wind energy generation system. The analysis is based essentially on solving the nonlinear equivalent circuit of the SP-SEIG, which is to find the per-unit frequency F and the magnetizing reactance Xm minimizing the determinant of the nodal admittance matrix Y instead of solving two non-linear equations with two unknowns. Hence, the equation-solving problem is converted to an optimization problem. The obtained minimum yields the adequate magnetizing reactance and frequency which will be used subsequently to compute the self-excitation process requirements in terms of the prime mover speed, the excitation capacitance and the load impedance on the one hand and to predict the generator steady state performance parameters on the other. In this work, the analysis is performed using three different global search algorithms, the genetic algorithm (GA), the particle swarm optimization (PSO) technique and the Taguchi optimization method (TM). A study of some simulation results is carried out using MatLab to compare between these three algorithms in terms of accuracy and guaranteed convergence in finding the minimum of the admittance.

Generalized model for investigating the attributes of a six-phase self-excited induction generator over a three-phase variant

Generalized model for investigating the attributes of a six-phase self-excited induction generator over a three-phase variant

Stability assessment of isolated six-phase induction generator feeding static loads

This paper presents the stability analysis of a six-phase self-excited induction generator (SP-SEIG) based on the eigenvalue stability criteria for its linearized model. This demonstrates the small signal stability behavior during steady-state operating conditions. The eigenvalue approach also establishes an opportunity to correlate eigenvalues with machine parameters. The investigation in this paper reveals that the eigenvalues are dependent upon the machine parameters, and the most critical parameter is the variation in magnetizing inductance (Lm) . The eigenvalues are varied in accordance with the machine variables and give focus to the stabilization of the SP-SEIG. A particular voltage build-up phenomenon is also experimentally verified to validate the proposed analytical approach in this paper.

Modeling and Analysis of Six-phase Self-excited Induction Generator Using Mixed Stator Current and Magnetizing Flux as State-space Variables

A simple two-axis (d-q) model of a saturated six-phase self-excited induction generator, aimed at a stand-alone renewable energy generation, is analyzed using mixed stator current and magnetizing flux as state-space variables. This new set of orthogonal transformation (dq0) is characterized with a four-saturation-element solely in-built system matrix. Selection of this model using proposed mixed variables is justified by its simplicity. Performance equations for the given machine use the magnetizing inductance (Lm) at steady state and the dynamic inductance (L). In view of simplifying the analysis, the effects of common mutual leakage inductance (Llm) and cross-saturation coupling (Lldq) across the d-q-axis of each stator have been pretermitted. The mathematical model presented herein has been verified by simulation results using a fourth-order Runge-Kutta subroutine. Analytical results were also validated by experimental results and were found to be in good agreement.

Wind-driven stand-alone six-phase self-excited induction generator transients under different loading conditions

This paper present the transient performance of an isolated six-phase self-excited induction generator (SPSEIG) driven by a fixed-pitch wind turbine. The approach is based on a wind-turbine model, SPSEIG model and detailed transient behaviour of an SPSEIG for stand-alone power generation, when subjected to sudden switching of balanced/unbalanced R, RL and RLC load for both three-phase winding sets. The computer model has been developed in an arbitrary reference frame. In the d–q axis model, the effects of common mutual leakage inductance between the two three-phase winding sets have been included. The simulation results show a good performance from the system under different loading conditions. While the interaction between the two windings is inevitable and variation of load at one winding set changes the operating conditions at the other winding, the situation is still satisfactory for a wide range of rural resistive loads.

Optimisation of voltage and frequency regulation in an isolated wind-driven six-phase self-excited induction generator

This paper presents a constant voltage operation of a Six-Phase Self-Excited Induction Generator (SPSEIG) driven by a fixed speed wind turbine using an Ant colony optimisation (ACO) technique to predict the behaviour of a the machine. In this paper, an attempt has been made to estimate the excitation capacitance requirements of a SPSEIG for maintaining rated terminal voltage and frequency. The range of capacitance variation required for maintaining constant terminal voltage while supplying a load of variable magnitude is evaluated. Analytical approaches, suitable for all the configurations of shunt capacitances such as variable excitation capacitance connected across (i) single three-phase winding set only and (ii) both the three-phase winding sets of an SPSEIG for operation as a simple shunt on no load and pure resistive load, are presented. The mathematical model developed is based on loop impedance method using graph theory. It is shown that the proposed technique is very effective and useful for making the SPSEIG feasible for remote areas with wind potential. The proposed approach is tested and compared with Genetic Algorithm (GA) and Fmincon technique.

Performance analysis of a simple shunt and series compensated six-phase self-excited induction generator for stand-alone renewable energy generation

This paper describes a new generalized and efficient model for performance analysis of a six-phase self-excited induction generator (SPSEIG) with three capacitor excitation topologies; simple shunt, short shunt and long shunt. Mathematical model of SPSEIG is formulated using nodal admittance method based on graph theory. Attention is focused on the influence of the different capacitor connections on the generator overload and output power capabilities. The generator voltage with simple shunt excitation connection collapses when it is overloaded while with either the short shunt or long shunt excitation connection; generator is able to sustain the load at a lower operating voltage and larger load current. The matrix equation developed by nodal admittance method is solved by Genetic Algorithm (GA) technique to predetermine the steady-state performance of SPSEIG. The experimental and theoretical results are found to be in good agreement.

Steady-state Modeling and Analysis of Six-phase Self-excited Induction Generator for Renewable Energy Generation

This article presents the steady-state modeling and analysis of a six-phase self-excited induction generator for stand-alone renewable generation. The basis of the analysis is the nodal admittance method based on graph theory as applied to the equivalent circuit. The proposed steady-state generalized model of a six-phase self-excited induction generator dispenses with the tedious work of segregating real and imaginary components of the complex impedance of the induction generator for deriving the specific models for each operating mode. Graph theory based matrix equations are easier to modify in order to account for specific effects such as uncompensated and compensated operation. The resulting equations have excellent symmetry, which makes the analysis very easy, fast, and accurate. The matrix equations developed by the nodal admittance method are solved by a genetic algorithm to determine the steady-state performance of a six-phase self-excited induction generator. The analytical results are found to be in good agreement with experimental results.

A self‐excited six‐phase induction generator for stand‐alone renewable energy generation: experimental analysis

AbstractMulti‐phase AC machines are nowadays widely considered as potentially viable solutions for numerous variable‐speed drive applications. With an increased emphasis on renewable electric energy generation, where interfacing with the grid typically takes place by means of power electronic converters, or if the generators are used for stand‐alone applications, the advantages of multi‐phase machines that make them viable for drive applications can also be effectively exploited in generating applications. This paper discusses behavior of a six‐phase self‐excited induction generator (SPSEIG) configured to operate as a stand‐alone electric energy source in conjunction with a hydro power plant. A purely experimental treatment is provided with the emphasis placed on operating regimes that illustrate the advantages of using a SPSEIG. In particular, it is shown that the SPSEIG can operate with a single three‐phase capacitor bank, so that the loss of excitation or fault at one winding does not lead to the system shutdown. The generator can also supply two separate three‐phase loads, which represents an additional advantage. Last but not least, outputs of the two three‐phase windings can be used to supply a single three‐phase load through an interconnecting six‐phase to three‐phase transformer, in which case failure of one three‐phase winding does not lead to the system shutdown and the load can be still supplied from the remaining healthy winding. Experimental results include study of self‐excitation transients, loading transients with independent three‐phase resistive and resistive–inductive load at each of the two three‐phase winding sets, and measured steady state characteristics for various load and /or capacitor bank configurations. Copyright © 2009 John Wiley & Sons, Ltd.

Modeling and experimental analysis of a self-excited six-phase induction generator for stand-alone renewable energy generation

This paper presents a simple d– q model of a saturated multi-phase (six-phase) self-excited induction generator (SP-SEIG). Performance equations for this machine are given which utilize the saturated magnetizing inductance L m=( λ m/ i m) and its derivative (d L m/d i m) rather than dynamic inductance L=(d λ m/d i m). In the analytical model, the effects of common mutual leakage inductance between the two three-phase winding sets have been included. A detailed experimental investigation about the voltage build-up, collapse of voltage, and various performance including loading and unloading characteristic, power capability and reliability of six-phase self-excited induction generator is also presented in the paper. Experimental results are recorded: (a) with capacitor bank connected across both the three-phase winding sets, and (b) with capacitor bank connected across only one three-phase winding set. Loading and unloading transients are recorded with independent three-phase resistive loads at each of the two three-phase winding sets, and measured steady-state characteristics for various load and/or capacitor bank configurations. Experimentations were also carried out to judge the performance of the SP-SEIG when three-phase load was connected via an interposed Y− Δ/ Y six-phase to three-phase transformer.

Analysis of a Saturated Multi-Phase (Six-Phase) Self-Excited Induction Generator

The present paper is concerned with the application of the equations of a saturated smooth air-gap machine to the analysis of the transient behavior of a multi-phase (six-phase) self-excited induction generator (SEIG). In the analytical model (d-q axis model), the effects of common mutual leakage inductance between the two three-phase winding sets have been included. A detailed experimental investigation of self-excitation process, loss of excitation and re-excitation, switching-in of pure resistive load without, and with series compensation (short shunt) is also included in this paper.