Acuson Corporation

Semipower Systems, Inc.

Karl Konecny

Thomas G Cooper

Alan W Petersen

David V Adams

A brushless sensorless DC motor assembly computes rotor position by examining the current measurements of the stator windings. The brushless DC motor assembly includes a rotor and a set of stator windings that are adapted to drive the rotor. In addition, a power amplifier is adapted to apply a voltage to each stator winding in sequence according to a received sequence of switching signals. Also included is a terminal that is adapted to receive a commanded rotor stopping position from a user input device or a controlling computer. A current sensing assembly permits the determination of the current through each stator coil to produce a sequence of stator coil current values over time. A data processor is adapted to calculate the sequence of switching signals based on the received commanded rotor position and the computed rotor position. The calculation of the computed rotor position is based on the most recent set of stator coil current values and the most recent set of the computed switching signals.

Brushless sensorless DC motor assembly with precisely controllable

A control device for converting a manual input into an electrical signal is provided. The control device includes a control button, a first magnet having a first predetermined polarity, a second magnet having a second predetermined polarity, and a hall-effect sensor located adjacent to the control button. The control button is mounted for pivotal displacement about a neutral position in accordance with the manual input. The first magnet and the second magnet are mounted to the control button. The polarity of the second magnet is opposite the polarity of the first magnet. The hall-effect sensor has an electrical input and an electrical output. The electrical signal produced by the control device may, for example, be used to control the velocity of a motor, which rotates an ultrasound transducer.

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Hillsboro, OR, United States of America

Karl Konecny