Patents by Inventor Todd A. Simonds

Todd A. Simonds has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Absolute position sensing method and apparatus for synchronous elevator machines by detection stator iron saturation
    Patent number: 6401875
    Abstract: A method and apparatus of determining the position of a rotor at standstill relative to a stator in a synchronous motor elevator machine includes injecting an AC current having a predetermined single frequency and a predetermined initial phase angle into a stator coil of the stator, and sampling the injected current and resultant voltage a predetermined number of times per period of the frequency. Subsequently the method calculates a stator inductance from the sampled voltages and currents using a DFT. By incrementing the initial phase angel a predetermined number of times over a 360 degree cycle, and repeating the injecting, sampling, and calculating with each incremented phase angle, the algorithm provides a predetermined number of calculated stator inductances. The position of the d axis relative to the stator is then determined from the minimum of the calculated stator inductances.
    Type: Grant
    Filed: February 12, 2001
    Date of Patent: June 11, 2002
    Assignee: Otis Elevator Company
    Inventors: Daryl J. Marvin, Mark Shepard, Todd A. Simonds, Alberto Vecchiotti, Vladan Petrovic