Disclosed is a controller of a grid coupled type doubly-fed induction
generator having a multi-level converter topology, which can control the
doubly-fed induction generator having a high voltage specification and
can perform a fault ride-through function, an anti-islanding function and
a grid voltage synchronization function required for a dispersed power
generation facility. The controller makes a H-bridge multi-level
converter generate a three-phase voltage waveform resulted from the
structure that single-phase converters each being composed of a 2-leg
IGBT are stacked in a serial manner, and controls a rotor current so as
to make the rotor coil of the doubly-fed induction generator in charge of
a slip power only. The boost converter is composed of a 3-leg IGBT and a
boost inductor generating a direct current voltage of its source required
for the H-bridge multi-level converter.