Patent ID: 6469469
Filing Date: 2002-10-22
Classification: H02P

Abstract:
A variable output induction motor drive system for use with a polyphase variable output alternating current motor including a rotor and stator to drive an operating load, said variable output induction motor drive system comprises a sine wave current generator operatively coupled to a direct current power source to receive direct current therefrom and to generate a variable frequency, variable amplitude sine wave current and operatively coupled to the polyphase variable output alternating current motor to selectively feed the variable frequency, variable amplitude sine wave current thereto and a sine wave power control coupled between said sine wave current generator and the polyphase variable output alternating current motor to monitor the operating parameters of the polyphase variable output alternating current motor and to control the amplitude and frequency of the variable frequency, variable amplitude sine wave current fed from said sine wave current generator to the polyphase variable output alternating current motor to control the output torque and speed thereof, said sine wave current generator comprises a frequency control stage, an amplitude control stage and a power control stage; said frequency control stage comprising a plurality of frequency control generators to generate a constant amplitude, variable frequency rectified signal corresponding to each of phases of the polyphase variable output alternating current motor; said amplitude control stage coupled to said frequency control stage comprising a plurality of amplitude control generators to control the amplitude of the constant amplitude, variable frequency rectified signal from the corresponding frequency control generator to generate a variable frequency, variable amplitude control rectified signal and said power control stage comprises a plurality of power control generators coupled to said amplitude control stage to modulate the DC input power from the DC power source with variable frequency and variable amplitude rectified signals from said corresponding amplitude control generators to generate the variable frequency, variable amplitude sine wave current fed to each corresponding phase of the polyphase variable output alternating current motor.