Abstract: The methods and devices provided herein include methods and devices for controlling a permanent magnet motor. In one implementation, a method is provided that allows for the determination of the values of the phase back EMF voltage and of the phase inductances while the phases are powered with a PWM (Pulse Width Modulation) controlled current and/or voltage.

Abstract: An electronic device is provided for controlling a motor having three phases driven by a motor driver. In one implementation, the electronic device includes a detection means and a control circuit. The detection means includes three high-gain differential amplifiers and three A/D converters. The detection means detects back EMF voltages induced by the rotation of the motor and applies corresponding signals to the control circuit. The control circuit computes and filters the position and/or the speed of the motor and then delivers the filtered values of the computed rotor position and/or speed to control the motor driver. The motor may thus be controlled even at near-zero rotational speed.

Abstract: An electronic device is provided for controlling a motor having three phases driven by a motor driver. In one implementation, the electronic device includes a detection means and a control circuit. The detection means includes three high-gain differential amplifiers and three A/D converters. The detection means detects back EMF voltages induced by the rotation of the motor and applies corresponding signals to the control circuit. The control circuit computes and filters the position and/or the speed of the motor and then delivers the filtered values of the computed rotor position and/or speed to control the motor driver. The motor may thus be controlled even at near-zero rotational speed.

Abstract: A handpiece and system having a surgical handpiece adapted to perform an operation on a patient, the surgical handpiece having a primary circuit being driven by an applied signal. A controller is operatively coupled to supply operating power to the surgical handpiece. A hand switch is operatively coupled in conjunction with the surgical handpiece to at least partially control an operation of the surgical handpiece. The switch has a secondary resonant circuit receiving the applied signal from the primary circuit and couples a response signal back to the primary circuit. Detection circuitry, operatively coupled to primary circuit, is responsive to a characteristic parameter of the response signal indicative of the presence of the hand switch in proximity of the surgical handpiece.

Abstract: A surgical instrument having an electric motor is discussed. The motor includes a motor output member, a driven member and a driving member. The driven member is coupled to the motor output member. The driving member includes a winding and a magnetically conductive portion comprising a plurality of laminations. The winding can be a self-supporting winding. The driving member, or at least the magnetically conductive portion thereof, is disposed proximate the driven member such that energizing the driving member imparts motion to the driven member. At least a portion of the driven member includes a magnet material. The magnet material can have a remanence of greater than or equal to about 1 T.

Abstract: An electric motor for use in a surgical procedure, including a motor output member, a driven member and a driving member. The driven member is coupled to the motor output member. The driving member includes a winding and a magnetic portion comprising a nanocrystalline alloy. The driving member, or at least the magnetic portion thereof, is disposed proximate the driven member such that energizing the driving member imparts motion to the driven member.