Modeling and Simulation of VSI Fed Induction Motor Drive in Matlab/Simulink

Abstract

The theory of reference frames and switching functions are effective in analyzing the performance of the induction motor fed from VSI (Voltage Source Inverter). In this work, mathematical model of Adjustable Speed Drive (ASD) is developed by taking synchronous reference frame equations for induction motor, switching function concept for VSI and non-switching concept for diode bridge rectifier. Simulation model of induction machine is implemented using dq0 axis transformations of the stator and rotor variables in the arbitrary reference frame. The corresponding equations are given in the beginning and then the developed model is implemented using MATLAB/Simulink. In this work, the proposed model is implemented using basic function blocks. The performance of induction motor is analysed for different frequencies. The developed model is tested for the steady state behavior of machine drive. The proposed mathematical model is validated by the simulation results. Keyword: Converters INTRODUCTIONIn many industrial applications Adjustable speed drives (ASD) are most commonly seen workhorses. In order to supply the motor with variable AC voltage or AC current with variable frequency Variable Frequency Drives (VFD) are employed. ASDs are used in pumping applications, in sugar cane industries, conveyor applications etc. The common VFD consists of a three phase diode bridge rectifier, dc link and a pulse width modulated inverter. It is necessary to develop a model for VFD for power system dynamic studies. In literature, for the three phase diode bridge rectifier dq impedance model is employed [1]. State-space averaging method is used for modeling a three phase four wire diode bridge rectifier [2]. Dynamic average value modeling methods are utilized for conventional three phase diode bridge rectifier and are validated [3]. This can capture the steady-state and transient characteristics of the diode bridge rectifier. An approximate switching function of the diode bridge rectifier is used in order to obtain the estimating function for the fundamental current harmonics [4].This method is proven to be effective in finding out the input current harmonic content. A switching function model for voltage source inverter is derived and also it is validated using MATLAB/Simulink [5].Modulation function theory is effectively utilized for deriving the Pulse Width Modulated (PWM) inverter which makes use of the Iterative Harmonic and Interharmonics Analysis (IHIA) [6]. Space vector pulse width modulation method is employed for inverter and the method is validated using MATLAB/Simulink [7]. A three phase boost dc-ac converter is used to supply the induction motor [8]. AC output voltage that is greater than the input dc voltage is obtained without the need of additional boost converter.

Determination of the Harmonic Losses in an Induction Motor Fed by an Inverter

“…Based on the theory of the transfer function of the VSI, the DC input voltage g to the inverter and the output currents (X d , X p , X ) are independent variables, while the input current g and the output line voltages (q dp , q p , q d ) are dependent variables. These variables are related as [20]:…”

“…In modern semiconducting techniques, the switching frequency and modulation index of PWM variable speed drives can be allowed to be further increased and eliminate all harmonics below the switching frequency. Although this technique can increase the machine performance and reduce noise emissions, the machine harmonic losses cannot be reduced considerably by increasing the switching frequency above 10kHz [15][16][17][18][19][20][21][22][23][24]. To model the harmonic losses of the induction machines with different power ratings, a complete equivalent circuit including all harmonic loss components was first presented in [5].…”

Modeling and simulation of a 3-ф induction motor based on two types of WFA

“…The self any two stator phases L aa , L bb , L cc have been calculated based on WFM as given in (14). Where the motor inductances formulas can be written as [25][26][27]:…”

Mathematical Modelling and Computer Simulation Assist in Designing Non-traditional Types of Precipitators and Separators

“…Marton [1][2][3] and Dţmura [4][5][6] focused on a particular shape, given by the geometry of a particle. In their calculations, they did not take full account of all the factors affecting the motion of particles in the electric [7][8][9][10][11][12][13][14]. The research method of mathematical modelling and computer simulation has proven to become a powerful approach for understanding the complexity of a physical, biological, chemical system [15][16][17][18].…”