AC machine controlled via amplitude modulation

Abstract

AC motor rotates independent from power frequency gives advantages in size and controllability. Oscillating and rotating magnetic field is created across airgap by using Amplitude Modulated input. Higher frequency (Carrier) is the power input and the lower frequency (Signal) determines speed of the motor. Stator and Rotor work as primary and secondary of transformer, rotor windings are arranged to keep resultant EMF generated within the winding as zero when rotor aligned with stator magnetic field and increase when deviates. The current generated on deviated rotor winding creates a push back torque keeping the rotor aligned with magnetic field. This interlocks magnetic field and the rotor. Two different frequencies are applied at either end of the stator windings so that the current flow through each winding become amplitude modulated, average of the two frequencies become carrier frequency and control frequency is half of the difference between two frequencies.

Dependencies are inferred from the claim text.