The Charles Stark Draper Laboratory, Inc.

Robert D Drescher

David B Eisenhaure

William E Stanton

David C Whipple

Emery St George, Jr

Richard L Hockney

Bruce G Johnson

An inertial energy storage device including a synchronous rotary electrical machine for bidirectional conversion between mechanical and electrical energy including: a stator having two axially spaced sets of circumferentially spaced teeth; field excitation means disposed on the stator to provide an axially polarized magnetic field; stator windings including a plurality of coils, each of which surrounds at least one tooth from each set; and a rotor having a plurality of circumferentially spaced teeth facing the stator teeth, and a circumferential flywheel mass radially spaced from its rotational axis; and a motor control circuit including sensor means for sensing the position of the rotor relative to the stator; means, responsive to the sensor means, for generating a waveform for driving the machine when it is operating as a motor; a voltage control circuit for controlling the amplitude of the waveform for driving the machine; and a current control circuit for controlling amplitude of the current provided to the machine.

Inertial energy storage device and synchronous rotary electrical machine

An optimum efficiency control system for a variable torque/speed rotary a.c. induction machine including means for varying the frequency and magnitude of the excitation voltage/current supplied to the machine in three optimum efficiency regions of operation, a first fixed slip frequency region, a second flux saturation region, and a third voltage saturation region; and means for commanding the means for varying in the first fixed slip frequency region of operation with an excitation frequency command signal derived from the machine rotor speed and unconstrained maximum efficiency slip frequency, and an excitation voltage/current command signal derived from the difference between the commanded torque/speed of the machine and its actual torque/speed; in the second flux saturation region of operation with an excitation frequency command signal derived from the machine rotor speed and slip frequency command signal derived from the machine rotor speed and slip frequency which is a function of the difference between the commanded torque/speed of the machine and its actual torque/speed; and an excitation voltage/current command signal derived from the difference between the saturation flux and actual flux in the machine; and in the third voltage saturation region of operation with the saturation voltage and an excitation frequency command signal derived from the machine rotor speed and slip frequency which is a function of the difference between the commanded torque/speed and actual torque/speed of the machine.

Optimum efficiency control system

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Cambridge, MA, United States of America

Robert D Drescher