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US 4,384,242 AGranted
Speed control systems of synchronous motors
AssigneesToshiba Kikai Kabushiki Kaisha, Kabushiki Kaisha Toei Denki Seisakusho
InventorTadahiro Ono
Life of this patent
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Abstract
In a speed control system of a synchronous motor, a pulse modulated signal containing a signal representing rotational angle of the motor is formed to control the speed. The pulse modulated signal is passed through a synchronous rectifier to obtain currents supplied to stator windings of the motor.
Claims8
A speed control system of a synchronous motor provided with a plurality of stator windings which are displaced electrically and mechanically by predetermined angles and a rotor, comprising:
- means driven by said rotor for producing a phase modulated signal E sin (.omega.t+.theta.), where E represents voltage, .omega.=2.pi.f, .theta. represents a rotational angle of said motor and f a frequency;
- speed signal converting means which forms a signal corresponding to a differential of said rotational angle;
- means for producing a speed instruction signal corresponding to a rotational speed of said rotor;
- means for producing an error signal corresponding to a difference between said signal formed by said speed signal converting means and said speed instruction signal;
- a multiplier for multiplying said phase modulated signal with said error signal;
- means for producing a plurality of reference signals having a phase difference of said predetermined angles;
- and
- synchronous rectifier means for rectifying an output of said multiplier according to said reference signals for producing currents supplied to said stator windings of said motor.
5 more elements
Dependencies are inferred from the claim text.