Abstract: A rotor position estimator for a permanent magnet motor with a stator and a rotor includes a sensing circuit that generates d-axis and q-axis negative sequence stationary current (NSSC) signals. A signal conditioning circuit combines the d-axis and q-axis NSSC signals with first and second positive feedback signals that are based on a rotor position estimate signal. A regulator is coupled to an output of the signal conditioning circuit. A mechanical system simulator that is coupled to the regulator and a demand torque signal generates the rotor position estimate signal. The signal conditioning circuit includes a second harmonic amplifying circuit that receives the rotor position estimate signal and outputs the first feedback signal to a first multiplier. The signal conditioning circuit includes an inverse saliency model receives the rotor position estimate signal and outputs the second feedback signal to a second multiplier.

Abstract: A rotor position estimator for a permanent magnet motor with a stator and a rotor includes a sensing circuit that generates d-axis and q-axis negative sequence stationary current (NSSC) signals. A signal conditioning circuit combines the d-axis and q-axis NSSC signals with first and second positive feedback signals that are based on a rotor position estimate signal. A regulator is coupled to an output of the signal conditioning circuit. A mechanical system simulator that is coupled to the regulator and a demand torque signal generates the rotor position estimate signal. The signal conditioning circuit includes a second harmonic amplifying circuit that receives the rotor position estimate signal and outputs the first feedback signal to a first multiplier. The signal conditioning circuit includes an inverse saliency model receives the rotor position estimate signal and outputs the second feedback signal to a second multiplier.

Abstract: A control system for an interior permanent magnet motor which includes five regulators to provide efficient control of the motor. Deviation from a desired maximum torque per amp trajectory is minimized by making two of the five regulators field-weakening regulators. First and second regulators provide current control of the quadrature-axis current and direct-axis current, respectively. A limiter limits the direct-axis current from exceeding the maximum allowed stator current and any excess current is added to the quadrature-axis current. Fourth and fifth regulators are field-weakening regulators. The fourth regulator generates a first field-weakening signal that increases the direct-axis signal when the quadrature-axis voltage approaches a desired maximum voltage. The fifth regulator generates a second field-weakening signal that decreases the quadrature-axis current signal when the direct-axis voltage approaches a desired maximum voltage.

Abstract: The absolute position of a rotor of a permanent magnet motor is determined by detecting an angular position of a direct axis of the rotor; and detecting a polarity of the rotor to determine the absolute position of the rotor. The polarity of the rotor may be determined by applying a square wave voltage to phase windings of a stator of the motor to generate an mmf vector parallel to the direct axis, measuring phase currents of the phase windings, determining a direct axis current responsive to the measured phase currents and the angular position, determining that the rotor is aligned with the mmf vector if the direct axis current is shifted positive, and determining that the rotor is aligned 180 degrees out of phase with the mmf vector if the direct axis current is shifted negative.

Abstract: A position sensorless interior permanent magnet drive system and methods for use in electric and hybrid electric vehicles. The interior permanent magnet drive system and method use two rotor position estimation techniques for low and high speed operation and an initial rotor magnet polarity detection technique used at stand-still conditions. The use of the two different rotor position estimation techniques in combination enhances system efficiency and accuracy.

Abstract: An induction motor drive uses direct vector control for zero speed start up. According to the invention, a speed sensorless induction motor is controlled at all speeds, including zero or substantially zero speed, using direct vector control. In order to utilize direct vector control at all speeds, it is necessary to derive accurate stator flux vectors at all speeds. This is accomplished in the present invention by calculating two sets of stator flux vectors in diverse manners. A first set of flux vectors is derived from measured stator terminal voltage quantities, and a second set of flux vectors is derived from measured stator current quantities. The first set of flux vectors is valid at non-zero speed and the second set of flux vectors is valid at substantially zero speed. The direct vector control utilizes one of the two sets of flux vectors in accordance with predetermined criteria indicative of zero and non-zero speed conditions.