Abstract

This paper evaluates the design and implementation of the proposed improved Two-level Rectifier and Self-commutated Voltage Source Inverter based SVPWM. Self-commutated inverter is an advance technique to enhance electrical system control that uses internal electronic switches with turn-on and turn-off capability to reverse polarity without needing an external AC power source. It was designed and built at the Power Electronic Laboratory (PEL), Faculty of Engineering, using power electronics semi-conductor devices like thyristors, insulated gate bipolar transistor (IGBT) switching devices with complex control circuitry, commutation mechanism integrated within the converter, and fast switching components. Space Vector in the α-β plane in (d-, q-axis) frame such as V_d,V_q, reference vector V_(ref,) and angle (θ) were evaluated. Dwell times T_a,T_b and T_0; switching time duration, vector sectors T_1,T_2,and T_0 and as well as each transistor (S_1 to S_6) switching time were determined. Simulation was conducted using Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW) software to implement the calculations for sector and region selection; duty times T_a,T_b,and T_0; and switching time for all sector and region. Results revealed that the proposed incorporated self-commutated SVPWM technique achieves near-unity power factor operations with minimal total harmonics distortion. Delivers superior performance by generating higher voltage levels, near-sinusoidal output waveform for line-to-line voltages and load currents; with current total harmonic distortion (THD) of 1.42% compared to 4.81% of conventional SVP WM; provides precise control over the speed and torque of the AC induction motor with soft-starting and deceleration; saved significant energy by automatically adjusting motor speed to match the load requirement; effectively reduces high-frequency ripples and minimized filtering requirements; and ultimately improves overall power quality. This implies that self-commutated converter sustained less harmonics distortion to machines drives.

Key words: Pulse width modulation, induction motors, self-commutation, voltage source inverters, labVIEW, industrial drives.