Importance

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Abstract

A method of operating a four quadrant motor involves (a) monitoring a motor voltage magnitude request signal which varies between zero and a maximum value and (b) monitoring a motor direction request input. In step (c), based upon the request signal and input monitored in steps (a) and (b), a voltage request reference signal is established. In a step (d) a current magnitude request signal is monitored and in a step (e) a first current request reference signal and a second current request reference signal are established based upon the signal monitored in step (d). In a step (f) a voltage across a current sense resistor of a bus connected for powering the motor is monitored and in a step (g) a sense resistor reference signal is established based upon the signal monitored in step (f). In a step (h) the first current request reference signal is compared with a feedback current signal and in a step (i) the second current request reference signal is also compared with the feedback current signal. In a step (j) the sense resistor reference signal is provided to a controllable amplifier and in a step (k) a positive/negative gain of the controllable amplifier is controlled based upon the voltage request reference signal, the comparison made in step (h) and the comparison made in step (i). In a step (l) a signal output of the controllable amplifier is sampled to generate the current feedback signal which represents an actual current of the four quadrant motor.

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First Claim