TRANSIENT CHARACTERISTICS OF INDUCTION MOTOR DRIVEN BY VOLTAGE SOURCE INVERTER WITHOUT DC LINK COMPONENTS

The voltage source inverter without dc link components does not have electrolytic capaci­tor and reactor (or resistor). The main circuit consists of inverter,rectifier and ac filter. The rectifier is the three phase bridge connections of 120° duration, and each diode has the antiparallel connected GTO for the reverse current flow path. This paper describes the analytical method and the calculated results on the stability of this sys­tem. The dc link voltage of the inverter takes immediately the influence of the ac source voltages. The stability analysis is performed by means of state variable method in consideration of the ac source voltages. In the equation of the small perturbations on the state variable from steady state, the stability is estimated by the dominant root in eigenvalues analysis. The stable and unstable characteristics with constant V/f control of induction motor are similar to the conventional voltage source inverter.