Patent ID: 8080950

Claim:
A system for controlling the speed of a motor driving a load, wherein the motor is electrically connected to a generator which is driven by an engine, said generator having a controllable field, said system comprising: a first control feedback loop configured to limit the difference between the magnetic flux in the rotor of the motor and a commanded level of magnetic flux wherein the magnetic flux in the rotor is estimated based on measurement of electrical inputs to the motor cables; and a second control feedback loop configured to limit the difference between the speed of the rotor of the motor and a commanded speed wherein the speed of the motor is estimated based on measurement of electrical inputs to the motor cables; the first and second control feedback loops being configured and operatively connected for: measuring voltage and current inputs to the motor cables; generating a signal representing an estimate of the rotor flux of the motor based on the measurements of the voltage and current inputs to the motor cables; comparing a flux rotor command signal with the signal representing an estimate of the rotor flux of the motor to generate a signal representing the rotor flux error; generating a flux excitation command signal based on the signal representing the rotor flux error, the flux excitation command signal controlling the excitation of the field of the generator; generating a signal representing an estimate of the speed of the motor based on the measurements of the voltage and current inputs to the motor; comparing a speed command signal with the signal representing an estimate of the speed of the motor to generate a signal representing the motor speed error; generating a throttle position command signal based on the signal representing the motor speed error the throttle position command signal controlling the position of the throttle of the engine; generating a torque engine command; and linearizing the torque engine command, wherein the gain of the throttle position control is near constant and easier to tune for optimum response.