WOUND-ROTOR INDUCTION MOTOR AND ENERGY CONVERSION FACILITY FOR VARIABLE SPEED ELECTRIC MACHINE

摘要

A wound-rotor induction motor comprises a wound stator, a wound rotor secured to the rotary shaft on the rotational center side of the wound stator, and a squirrel cage rotor provided on the rotational center side of the wound rotor. An energy conversion facility for a variable speed electric machine having a wound-rotor induction machine regenerates AC power in an AC system connected with the primary and secondary windings through a rectifier, a chopper circuit, a capacitor and an inverter. Even if the current flowing through the secondary winding contains harmonics, an induction current flows through the conductor of the squirrel cage rotor to cancel the rotating field generated in the wound-rotor by the harmonics, and hence the harmonics in the current flowing through the secondary winding is attenuated. The harmonic power is restrained from flowing out to the outside of the facility, and high quality power of which the distortion of the output voltage is suppressed can be generated.