1992 Volume 112 Issue 1 Pages 38-44
Current Source PWM Inverter has no delay time Td in principle, and supplies currents for a motorexactly. In addition, the induction motor has little magnetic noise, since the voltage wave forms of the motor are almost sinusoidal.
Making good use of these characteristics of the current source inverker, the drive system havinghigher performance can be achieved without speed sensors. Above all, as the current and voltage are nearly sinusoidal wave forms, motor constants and parameters can be measured precisely under motor operation.
If the motor parameters are given exactly, a vector-controlled system may be achieved theoreti-cally, where secondary resistance R2 is omitted in the control low for the inverter angular frequency ω1. Furthermore, it is possible to estimate the precise angular speed of a motor.
In this paper, the principle and performance characteristics of this method are discussed. The simulation and experimental results of the tested machine show that the proposed method is very effective for improvement of the system characteristics, such as little speed regulation.