8/19/2019 A Unified Method for Modeling and Simulation of Three Phase Induction Motor Drives http://slidepdf.com/reader/full/a-unified-method-for-modeling-and-simulation-of-three-phase-induction-motor 1/5 A UNIFIED METHOD FOR MODELING AND SIMULATION OF THREE PHASE INDUCTION MOTOR DRIVES H. Maqbahi, A. Ba-razzouk, J Xu, A. Cheriti and V. Rajagopalan Chaire de recherche industrielle Hydro-QuCbecNQTR Dtpartement de genie Clectrique et gtnie informatique Universitk du QuCbec 2 Trois-Rivi res C.P. 500, Trois-Rivikres, PQ, G9A 5H7, CANADA E-mail: macbahi@uqtr.uquebec.ca ABSTRACT : This paper presents a new approach for modeling and simulating the dynamic behavior of a large, interconnected, nonlinear, time-varying physical system consisting of a three-phase induction motor drive. An example of a vector-controlled induction motor shows that the proposed method is very accurate and very fast. The proposed simulation method and algorithm are expected to overcome some of the disadvantages of the existing methods. Simulation results are presented to illustrate the capabilities and flexibility of the simulation technique. A comparative evaluation with PSIM results is also provided to confirm the simplicity and the accuracy of the proposed unified method. 1. INTRODUCTION The design and performance analysis of many power systems require computer simulation since prototype testing has become almost impossible due to high costs. If the circuit incorporates a number of semi-conductor switches, machines and feedback control, computer simulation is the only viable solution for testing a design. In the literature [l], numerous digital computer simulation studies of induction motors fed from power electronic converters have been reported. Majority of these studies neglect the power electronic topology, and the converter is modeled as an ideal source wt zero impedance. Current research is directed towards developing simulation methods, which can efficiently and accurately describe the behavior of the circuit without complexity in problem formulation or long computation. An alternative way for formulating the dynamic drive analysis was suggested [2], using: first a simplified dq transformation so that the stator variables are in the actual abc phase quantities, second the semiconductor switches are modeled as binary inductors, a low value during the conduction, and infinite otherwise. Additionally, this analysis has been based on a state space formulation of the circuit equations. This, in it self, poses several difficulties, when considering the development of a general- purpose software [3]. Despite the fact that a variety of state-space based formulations have been described in the literature, it is not particularly well suited for implementation within a general simulation package. An alternative way for formulating the dynamic drive analysis is suggested [4] using Transmission- Line Modeling (TLM) technique. The induction motor is presented in dq frame. Furthermore, the authors have decoupled the system by introducing small inductors between the inverter and the motor section. The disadvantage of this approach is the introduction of additional elements, i.e., the number of nodes and branches increases. Furthermore, the link of transmission line must be large in order to reduce the errors when performing the decoupling of the system [5]. However, from a simulation and control perspective, only the actual phase variables are needed. Consequently, in control schemes and in simulating real power networks we are forced to transform back current and voltage variables to the phase reference frame. The main goal of this paper is to present a new dynamic model for three-phase induction motors using a new unified method. This method is based on the discrete-time machine model. In our approach, we will directly use the phase variables to simulate electrical machine dynamics. The solution presented in this paper will be used for implementation on a parallel computer and will be given in a next paper. This paper will demonstrate that it is feasible to simulate a vector-controlled induction motor drive with the proposed method used along with the commercially available software: MATLAB- SIMULINK [6]. 2. BASICS OF DISCRETE-TIME MODELING Before considering the simultaneous solution of the whole network as presented in next section, the basic numerical equations for individual power systems components shall be first reviewed. From the numerical integration point of view, the differential equation characterizing a capacitor or inductor can be approximated by a resistive circuit in series or in parallel with the integration algorithm [7]. This formulation can be called Discrete Time Modeling @TM) . 0-7803-5957-7/00/ 10.00000 EEE 345
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A Unified Method for Modeling and Simulation of Three Phase Induction Motor Drives
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8/19/2019 A Unified Method for Modeling and Simulation of Three Phase Induction Motor Drives