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The presence of forced oscillations occurring in a Wells Turbine driven grid-connected induction generator enables one to seek a solution by considering the analogy between the dynamics of the Wells Turbine driven systems with those associated with diesel-engine driven generators or electric motors driving reciprocating compressors, where also such forced oscillations occur, although there they occur in synchronism with shaft-position or speed. This difference is taken into account and the hunting network theory, which has hitherto been applied to the dynamic analysis of motors driving reciprocating compressors, is here applied to analyse the dynamics of a Wells Turbine driven grid-connected induction generator. The method enables the generator current, power and slip to be predicted from a knowledge of the shaft-torque harmonics. The result is compared with that obtained through d-q analysis.

This paper presents dynamic performances of an isolated self-excited induction generator (SEIG) under different power-factor loading conditions. Both simulated results based on computer simulations and experimental tests based on a laboratory 1.1 kW induction motor driven by a dc motor are clearly compared. Characteristics of both terminal voltage and magnetizing reactance of the studied SEIG subject to sudden connection and disconnection of various power-factor loads are investigated. Key words: induction generator, self excitation, loading conditions, dynamic analyses.

Dynamic analysis of a single-phase induction motor is studied using PSPICE software. The machine dynamics are presented by a set of nonlinear time-varying differential equations. The equations which define the motor operation are represented in an orthogonal system. The electric circuit presenting this set of equations is determined and solved by PSPICE software for simulation of the motor. The simulation results are compared with those obtained by EMTP and the experiment. Good agreements are observed for both cases. Key Words: Single-phase induction motor, transient operation, PSPICE application

The behavior of large induction motors during transient as well as steady state running conditions is of significant interest to the power industry. A variety of analytical predictive tools are employed to aid the design and predict their operation under transient and steady state conditions. One of the most powerful methods for investigating the transient behavior of induction machines is a coupled time stepping finite element analysis which can combine electromagnetic fields, circuits and mechanical systems [1, 6]. Due to the complexity of the finite element induction machine model and the resulting large number of describing equations, the computation time required for such programs to solve practical problems becomes a major limitation. This becomes even more of a concern when different design options or operating scenarios are evaluated. This paper presents a strategy to reduce the required running time in order to make a parametric study of induction machines such as the assessment of different design options feasible. This is accomplished by reducing the number of finite element equations that must be solved while maintaining the same level of accuracy of solutions. Keywords Induction Machines, Finite Elements, Transient Response, Computer Models, Model Reduction, Kron's Reduction

The starting of an induction machine at constant voltage and frequency is studied. A new method of order reduction and decoupling is given. It leads to approximate analytical expressions which describe with accuracy the dangerous torque oscillations.

This paper presents a mathematical modeling that uses the concept of harmonic inductances to derive voltage and torque equations of a three-phase induction machine using a, b, c and A, B, C formulation. Phase currents and electromagnetic torque are obtained by numerical integration of equations considering any supply voltage waveform. Two cases were studied - operation of induction motor supplied with sinusoidal waveform, and operation of an induction motor supplied by a three-phase inverter. Keywords: harmonics, induction motor, three-phase model