Polyphase Synchronous Machine Research Articles

Vectorial Formalism of Polyphase Synchronous Machine With Permanents Magnets

Abstract- This paper presents a mathematical model that transforms the real machine to fictitious machines and our goal is to simulate these and see the behavior of these machines in load. The polyphase machines are developed mainly in the field of variable speed drives of high power because increasing the number of phases on the one hand allows to reduce the dimensions of the components in power modulators energy and secondly to improve the operating safety. By a vector approach (vector space), it is possible to find a set of single-phase machine and / or two-phase fictitious equivalent to polyphase synchronous machine. These fictitious machines are coupled electrically and mechanically but decoupled magnetically. This approach leads to introduce the concept of the equivalent machine (multimachine multiconverter system MMS) which aims to analyze systems composed of multiple machines (or multiple converters) in electric drives. A first classification multimachine multiconverter system follows naturally from MMS formalism. We present an example of a pentaphase (polyphase) synchronous machine for a simulation and study the behavior of the machine load. Keywords: Polyphase machines, multimachine concept, vector space, eigenvectors, eigenvalues, pentaphase machine.

A Vectorial modeling for the Permanent Magnet Synchronous Machine (polyphase) based on multimachine approach

Our goal in this article is to present a model based on the Vectorial modelling associated with the multimachine concept. And we finish this work by a simulation to understand the behavior of the machine pentaphase (polyphase) in normal mode. The polyphase machines are developed mainly in the field of variable speed drives of high power because increasing the number of phases on the one hand allows to reduce the dimensions of the components in power modulators energy and secondly to improve the operating safety. By a vector approach (vector space), it is possible to find a set of single-phase machine and / or two-phase fictitious equivalent to polyphase synchronous machine. These fictitious machines are coupled electrically and mechanically but decoupled magnetically. This approach leads to introduce the concept of the equivalent machine (multimachine multiconverter system MMS) which aims to analyze systems composed of multiple machines (or multiple converters) in electric drives. A first classification multimachine multiconverter system follows naturally from MMS formalism. We present an example of a pentaphase synchronous machine.

Vectorial formalism for analysis and design of polyphase synchronous machines

A vectorial formalism for analysis and design of polyphase synchronous machines without reluctance and saturation effects is described. We prove the equivalence of such a machine with a set of magnetically independent machines, which are electrically and mechanically coupled. Specific problems of polyphase machines can thus be favorably analyzed with this concept. Rules of conception and constraints on electric supply can be deduced. Moreover the vectorial approach, which generalizes the complex phasor method, can also be used to control n -leg voltage source inverters. This methodology is applied to 3-phase and 6-phase synchronous machines.

Theorems of Torque Coefficients on Stability of Induction and Reluctance Machines

Theoretical work has been developed for investigating the performance of the damping and synchronizing torque coefficients for polyphase induction machines and synchronous reluctance machines. Six theorems are analytically formulated and proved. These are used as a new study in machine stability courses and are found to be useful for engineering education.

Simulating electric machine performance

This paper presents details of a computer program EMSP (Electric Machine Simula tion Program), which provides the capabil ity to simulate the steady state and dynamic performance of five fundamental devices: the transformer; the dc machine; the polyphase induction machine; the polyphase synchronous machine; and the single phase induction machine. A power factor correction analysis is also provided. EMSP constructs its machine simulation models from approximating functions derived from ANSI/IEEE/NEMA standards, from the author's own expertise, from information provided in manufacturer's application guides, and from user-provided data.

DC Standstill Torque Used to Measire Lq of Reluctance and Synchronous Machines

An experimental method for measuring the quadrature axis inductance (Lq) of polyphase synchronous machines is developed. It is based on a measurement of developed torque with the rotor at standstill and with the stator winding supplied with dc currents. While applicable to all synchronous machines, it is developed and explained for reluctance motors primarily. Special techniques are used to minimize measurement errors due to hysteresis and due to air gap permeance harmonics. Detailed results are presented for one reluctance motor which has a highly variable Lq, and correlation with other methods is found to be quite good. The effects of saturation are observed, and Lq is found to depend on quadrature axis current in the tested motor, with direct axis current having a slight effect on Lq at larger currents.

A Novel Project: The Design and Construction of a Helical-Pole Polyphase Synchronous Machine

This paper describes the design and assembly of a novel prototype three-phase synchronous machine constructed as a closely-sponsored undergraduate student project. The machine is significantly different from its more traditional counterparts in that the rotor and stator pole configurations are each in the form of a full-pitch helix, rather than parallel to the axis of rotation. A primary objective of this paper is to illustrate that a construction and design project such as this can be of special attractiveness and value to students in a university having relatively limited laboratory facilities for power-systems research. In addition, the scope of the traditional polyphase synchronous machine is enlarged in an innovative way. The novel features of this prototype machine are described and the design and construction sequences leading to its completion are outlined. The value of such an innovative project to the student, his faculty sponsor, and the department are assessed.

On the Determination of Constants and the Calculation of Asynchronous Starting Characteristics of Polyphase Synchronous Machines with Damper Winding

On the Determination of Constants and the Calculation of Asynchronous Starting Characteristics of Polyphase Synchronous Machines with Damper Winding

Torgues due to Time Harmonics of Salient Pole Type Polyphase Synchronous Machine with A. C. Field-Winding

Torgues due to Time Harmonics of Salient Pole Type Polyphase Synchronous Machine with A. C. Field-Winding

An Analysis of the Salient Pole Type Polyphase Synchronous Machine with Damper Winding when Ripple Voltage is Given to the Field Winding

An Analysis of the Salient Pole Type Polyphase Synchronous Machine with Damper Winding when Ripple Voltage is Given to the Field Winding

Equivalent Circuits for Cylindrical-Rotor, Reluctance, and Salient-Rotor Synchronous Machines

This paper presents a unified approach to the steady-state analysis of polyphase synchr-onous machines of three major types: cylindrical rotor, reluctance, and salient rotor. The major magnetic parameters of the machines are derived. Single-phaseequivalentcircuits are developed for each of the machine types. These equivalent circuits may be incorporated directly into the single-phase network representing a power system.

Switching Transients in Single-Phase Induction Motors [includes discussion

The subject of transients in polyphase induction motors and synchronous machines has been studied in very great detail by several investigators, but no published literature exists dealing exclusively with the analysis of the problem of transients in single-phase induction motors. This particular problem has been studied in this paper by applying the Laplace transform. The results of actual computation of the currents and developed electrical torque are compared with the data obtained by setting up the integro-differential equations of the machine on an electronic differential analyzer. It is shown that if the motor is switched on to the supply when the potential passes through its zero value, there is a pulsating fundamental frequency torque superimposed on the average steady-state unidirectional torque. If, on the other hand, the switch is closed when the applied potential passes through its maximum value, the developed electrical torque settles down to its final steady-state value during the first cycle of the supply voltage.

Synchronous machines with unsymmetrical loading

It is pointed out in the paper that the performance of polyphase synchronous machines with balanced loading can be predetermined reasonably satisfactorily by several well-known methods, but that very little attention has been given to the calculation of performance with unsymmetrical loading, when normal values of saturation apply.The paper outlines a simple analysis of a synchronous machine for the latter conditions—i.e. when carrying unbalanced currents of normal magnitude. It is shown how the standard methods, used for performance calculations with balanced operation, may be adapted for unbalanced conditions.The test results confirm the validity of the suggested technique.

Variable armature leakage reactance in salient-pole synchronous machines

The electrical performance characteristics of a polyphase synchronous machine, that is, its voltage-current relations under load, depend essentially upon the nature and the extent of the magnetomotive forces of the armature currents. Broadly speaking, the effect of these magnetomotive forces is two-fold; i. e., (a) they oppose and distort the field magnetomotive force and (b) they create leakage fields linked with the armature conductors. The first influence is known as the armature reaction, and the second as the armature reactance. More specifically, in a machine with salient poles, the armature reaction may be resolved for purposes of computation into the direct reaction (along the center lines of the poles) and the transverse reaction, midway between the poles. In polyphase machines of usual proportions, the armature leakage reactance, x, usually plays a secondary role, and for most purposes is assumed to be constant and independent of the power factor of the load. The vector of the reactive drop, Ix, is simply drawn in a leading time quadrature with the current I. However, in machines with considerable armature reactance, or where higher accuracy is required, the assumption of a constant x leads to noticeable discrepancies between the computed and observed data. This is of particular importance in problems which involve hunting, instability, etc., and in which the torque (or displacement) angle must be predicted. This angle depends to a considerable degree upon the leakage reactance of the machine. It has been previously proposed by others to use two distinct values of leakage reactance, one when the leakage paths around a group or belt of armature slots are closed through the center of a pole face (maximum reactance), and the other when such slots are midway between the poles (minimum reactance). However, no account has been taken apparently of a gradual change in the reactance between the two extreme positions, nor have the results been properly correlated with the rest of the factors which enter in the performance of the machine. In the present paper, the leakage inductance is assumed to consist of two parts, one of which is constant (the average inductance), and the other, varying harmonically at a double frequency, reaches a maximum opposite the centers of the poles. A magnetic linkage equation is written, and its derivative with respect to the time angle is taken to obtain the induced voltage. The result shows that the foregoing assumption leads to two reactive drops, one, the usual average Ix drop and another a supplementary drop, leading Ix by an angle 2 ψ, where ψ is the internal phase angle at which the machine is operating. These quantities are introduced in the usual Blondel diagrams for the generator and the motor, and the relationships among the various quantities are established both graphically and analytically.

Variable Armature Leakage Reactance in Salient-Pole Synchronous Machines

The electrical performance characteristics of a polyphase synchronous machine, that is, its voltage-current relations under load, depend essentially upon the nature and the extent of the magnetomotive forces of the armature currents. Broadly speaking, the effect of these magnetomotive forces is two-fold; i. e., (a) they oppose and distort the field magnetomotive force and (b) they create leakage fields linked with the armature conductors. The first influence is known as the armature reaction, and the second as the armature reactance. More specifically, in a machine with salient poles, the armature reaction may be resolved for purposes of computation into the direct reaction (along the center lines of the poles) and the transverse reaction, midway between the poles. In polyphase machines of usual proportions, the armature leakage reactance, x, usually plays a secondary role, and for most purposes is assumed to be constant and independent of the power factor of the load. The vector of the reactive drop, Ix, is simply drawn in a leading time quadrature with the current I. However, in machines with considerable armature reactance, or where higher accuracy is required, the assumption of a constant x leads to noticeable discrepancies between the computed and observed data. This is of particular importance in problems which involve hunting, instability, etc., and in which the torque (or displacement) angle must be predicted. This angle depends to a considerable degree upon the leakage reactance of the machine.