Simulation and Analysis of SVPWM Based 2-Level and 3-Level Inverters for Direct Torque of Induction Motor

In this paper, new scheme of direct torque control of induction motor for electric vehicles is proposed and the results of an investigation into suitable torque control schemes are also presented. The electric vehicle drive consists of rewound induction motors and a three-level IGBT inverter. The schemes investigated are Field Oriented Control, Direct Torque Control (DTC), and DTC using Space Vector Modulation. The results of Matlab - Simulink simulations and a comparison between the control schemes are presented. It is found that the DTC using Space Vector Modulation scheme is best for this application.

For industrial applications, variation in the output voltage of inverter is often required.

This is mainly for

Overcoming the variation in dc input voltage.

Maintaining the v/f ratio of induction motor constant.

Compensating for regulation of inverters.

Here space vector control for voltage control of multi level inverters which are gaining lot of importance in industry.

This paper is to acquire the knowledge on space vector control of PWM, its various advantages and to have complete idea on the operation of Multi level inverters, then employ space vector approach to PWM to control the output voltage of multi level inverters. This paper presents the implementation of a high-performance direct torque control (DTC) of induction machines drive.

DTC has two major problems, namely, high torque ripple and variable switching frequency. DTC is a control method that embeds a motor and inverter together and controls them together in an optimal manner. The new torque and flux controllers with constant switching frequency and low torque and flux ripples for direct torque control induction machine drives are presented. The core of these proposed controllers is based on the comparison between the compensated error signals with high frequency triangular waveforms, thus does not require complex calculation to generate the inverter switching signals. The controllers are therefore implemented using analog and/or digital circuits. Modeling and simulation of the new controllers are presented and the results show that the torque and flux ripples are reduced significantly. In order to solve these problems, this paper proposed a pair of torque and flux controllers. The simulation of the proposed controllers applied to the DTC drive is presented in MATLAB/SIMULINK. The simulation results are then verified.