Speed control systems of synchronous motors
First Claim
Patent Images
1. 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 (ω
t+θ
), where E represents voltage, ω
=2π
f, θ
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.
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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.
22 Citations
8 Claims
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1. 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 (ω
t+θ
), where E represents voltage, ω
=2π
f, θ
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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification