Abstract: Field oriented induction motor system including a field oriented induction motor having an associated torque current and an associated flux current and a predetermined current ratio, wherein the predetermined current ratio is defined as the ratio of the torque current to the flux current, and wherein the predetermined current ratio is dependent upon the saturation state of the motor. A method for selecting the ratio of torque current to flux current for a field oriented induction motor including applying an allocation factor to the torque current and flux current, wherein the allocation factor is dependent upon the saturation state of the motor. The saturation state of the motor is determined based upon motor parameters.

Abstract: System and method for controlling the output torque of an electrical machine include a torque controller operable for receiving a motor input command, representative of a desired output torque, and generating a drive command to direct a motor to produce a predetermined output torque based on the motor input command. Further, the torque controller may include a sensor system for generating a feedback signal representative of an actual output torque of the motor. Additionally, the torque controller includes an input modulator and a speed modulator for adjusting the drive command based on the feedback signal and based on the motor input command to control a value of the predetermined output torque and to control a rate at which the predetermined output torque reaches the desired output torque.

Abstract: A method and system for detecting the negative sequence of three phase grid-connected inverter systems utilizes, for example, computer hardware and/or computer software to remove a direct current component from a direct-axis current feedback for a three phase current of the inverter system to yield a pure alternating current waveform signal. A first low pass filter eliminates high frequency noise from the alternating current waveform signal while passing a negative sequence signal. The filtered signal is rectified to an absolute value, and a second low pass filter flattens the rectified signal to an output signal that is indicative of the magnitude of the negative sequence current.

Abstract: A speed controller circuit for a motor including a ramp function generator having a first input connected to a source of a speed demand signal and a second input connected to a ramp step signal. The ramp function generator develops a frequency ramp that has a slope is initiated by the speed demand signal which is adjusted in response to the ramp step signal. The ramp function generator also provides a frequency signal wherein the ramp function increases or decreases the frequency according to the speed demand. A V/F circuit to the ramp function generator and a space vector modulation circuit are connected to the V/F circuit. The output of the space vector modulation circuit is applied through power switching devices to the motor for speed control. A PI controller circuit is connected to a motor current feedback signal and to a maximum current signal, which provides the current limit of the control system.

Abstract: An inverter circuit system for controlling the voltage level at the neutral point of a three-phase wye-connected load. A dc voltage source such as a pair of batteries in series and having first and second poles is connected by one pole to an inverter bus and connected by the other pole via an inductive impedance to the neutral point of a three-phase wye-connected load.

Abstract: The present invention provides vibration control for a vehicle drivetrain. In one embodiment of the present invention, a vibration control method comprises generating a speed signal representing a rotational speed of the drivetrain. The method further includes half-wave rectifying the speed signal to generate a first signal. Also, the method comprises inverting the speed signal and half-wave rectifying the inverted signal to generate a second signal. Also, the method includes low-pass filtering the first signal to generate a third signal and low-pass filtering the second signal to generate a fourth signal. In addition, the method comprises selecting a minimum of the third and fourth signals to generate a fifth signal.