Babak Asghari

Experimental Validation of a Geometrical Nonlinear Permeance Network Based Real-Time Induction Machine Model

Real-time digital simulation of electrical machines and drives is a cost-effective approach in evaluating the true behavior of newly designed machines and controllers before applying them in a real system. Although many studies exist regarding the optimized models of power electronic drives and digital controllers for real-time simulation, the real-time models of electrical machines are still limited to the lumped parameter electric circuit models. This is mainly due to the complexity of a detailed electrical machine model which makes it computationally expensive. This paper presents the modeling, real-time implementation, finite element analysis, and experimental validation of a nonlinear geometrical permeance network based induction machine model. A nonlinear permeance network model (PNM) is developed for the real-time simulation of a 3-hp squirrel cage induction machine with closed rotor slots. Several studies both under open-loop and closed-loop control conditions are conducted, and the results obtained from the offline and real-time simulations and the experiment are compared with each other to show the effectiveness of the proposed PNM model.

Interfacing Techniques for Electromagnetic Field and Circuit Simulation Programs IEEE Task Force on Interfacing Techniques for Simulation Tools

Interfacing of disparate simulation programs is increasingly undertaken to gain a deeper understanding of their functionality and exploit their merits for modeling complex systems. In this paper, techniques for interfacing field and circuit equations of low-frequency electromagnetic apparatus are reviewed, analyzed, and classified into two main categories of direct and indirect methods according to the coupling method. Each category includes a vast array of techniques employing different methods for circuit modeling. The field analysis is restricted to 2-D finite-element method, which is a widely used numerical technique for modeling magnetic behavior of power apparatus. The main features and problems associated with each technique are summarized. Methods for coupling of mechanical equations are addressed in a separate section. A comprehensive list of references is also included at the end of this paper to provide further information to the readers.

Novel Transmission Line Modeling Method for Nonlinear Permeance Network Based Simulation of Induction Machines

This paper studies different iterative solution methods for nonlinear permeance network based machine models. A new transmission line modeling (TLM) algorithm for efficient solution of permeance network models (PNM) of induction machines is proposed. In this method, the TLM algorithm is used to decouple the nonlinear magnetic equations. The decoupled nonlinear equations are then solved by a look-up table method owing to the repetitive nature of equations across the geometry of the machine. It is shown that the proposed method offers significant speed-up compared to the conventional Newton-Raphson method. Simulation results for dynamic and steady-state conditions of a closed rotor slot induction motor are compared with experimental test results as well as finite element analysis to evaluate the performance of the proposed algorithm.

Real-Time Nonlinear Transient Simulation Based on Optimized Transmission Line Modeling

This paper proposes an optimized transmission line modeling (TLM) method for the real-time transient simulation of systems with multiple nonlinearities. The proposed method allows the simulation to be carried out with larger time-steps while maintaining the accuracy. A detailed case study of a nonlinear bridge circuit is presented to illustrate the advantages of the optimized TLM method in comparison with other methods. The new formulation is then implemented in real-time for the transient simulation of the nonlinear bridge. Real-time simulation results are validated by comparing them with experimental measurements. A second case study includes a power system with several surge arresters which is also simulated in real-time by the aid of the optimized TLM method and verified using offline simulation.

Experimental validation of a geometrical nonlinear permeance network based real-time induction machine model

Real-time digital simulation of electrical machines and drives is a cost-effective approach to evaluate the true behavior of newly designed machines and controllers before applying them in a real system. Although many studies exist regarding the optimized models of power electronic drives and digital controllers for real-time simulation, the real-time models of electrical machines are still limited to the lumped parameter electric circuit models. This is mainly due to the complexity of a detailed electrical machine model which makes it computationally expensive. This paper presents the modeling, real-time implementation, finite element analysis, and experimental validation of a nonlinear geometrical permeance network based induction machine model. A nonlinear permeance network model (PNM) is developed for the real-time simulation of a 3 hp squirrel cage induction machine (SCIM) with closed rotor slots. Several studies both under open-loop and closed-loop control conditions are conducted and the results obtained from the off-line and realtime simulations and the experiment are compared with each other to show the effectiveness of the proposed PNM model.

Novel transmission line modeling method for nonlinear permeance network based simulation of induction machines

This paper studies different iterative solution methods for nonlinear permeance network based machine models. A new transmission line modeling (TLM) algorithm for efficient solution of permeance network models (PNM) of induction machines is proposed. In this method the TLM algorithm is used to decouple the nonlinear magnetic equations. The decoupled nonlinear equations are then solved by a look-up table method owing to the repetitive nature of equations across the geometry of the machine. It is shown that the proposed method offers significant speed-up compared to the conventional Newton-Raphson method. Simulation results for dynamic and steady-state conditions of a closed rotor slot induction motor are compared with experimental test results as well as finite element analysis to evaluate the performance of the proposed algorithm.

Real-time nonlinear transient simulation based on optimized transmission line modeling

This paper proposes an optimized transmission line modeling (TLM) method for the real-time transient simulation of systems with multiple nonlinearities. The proposed method allows the simulation to be carried out with larger time-steps while maintaining the accuracy. A detailed case study of a nonlinear bridge circuit is presented to illustrate the advantages of the optimized TLM method in comparison with other methods. The new formulation is then implemented in real-time for the transient simulation of the nonlinear bridge. Real-time simulation results are validated by comparing them with experimental measurements. A second case study includes a power system with several surge arresters which is also simulated in real-time by the aid of the optimized TLM method and verified using offline simulation.