Automatic-control system for the angular speed of a synchronous motor

Claim 1

An automatic-control system for the Angular velocity of a synchronous motor having a stator provided with an excitation winding and an armature provided with an armature winding electromagnetically coupled to the excitation winding in an airgap between stator and armature, said control system comprising: a forced commutation thyratron-type inverter connected with said armature winding; rectifier means supplying said inverter with a direct current power voltage; a first control chain connected to said armature winding and including: a voltage/frequency converter responsive to a continuous voltage for producing a chain of ignition pulses and connected with said inverter for rendering same conductive at a frequency determined by the voltage applied to said voltage/frequency converter, a voltage/duration converter responsive to an applied continuous voltage for generating a pulse train homologous with the pulses of said voltage/frequency converter but with a time delay determined by the level of the voltage applied to said voltage/duration converter, said pulse train being applied to said inverter to terminate conduction thereof, whereby said inverter applies to said armature winding pulses of a cadence determined by the voltage applied to the voltage/frequency converter and of a duration determined by the voltage applied to the voltage/duration converter, and feedback means responsive to the phase angle of angular velocity of said armature for producing a voltage proportional to deviation of said phase angle from a predetermined phase angle for controlling the delay time of said voltage/duration converter in a sense tending to eliminate said deviation; and a second control chain inductively coupled with said first control chain in said gap and including: a function generator coupled with said motor for generating a periodic signal whose period is controlled by a rotation speed of the motor, a source of a continuous excitation control voltage, summing means connected to said junction generator and said source of continuous excitation-control voltage for algebraically combining the outputs thereof and producing a modulated excitation current; and means for applying said modulated excitation current to said excitation winding.

Claim 8

A method of controlling the operation of a synchronous motor having an excitation coil and variable angular velocity from an alternating current line source, said method comprising the steps of: rectifying an alternating current input from said line source to produce a direct current; triggering a thyristor inverter with a train of pulses to connect the direct current to said motor during conductive periods of the thyristor inverter whereby said motor is driven at a rate determined by the frequency and duration of said pulses; deriving a first signal representing the phase angle of the angular velocity of the motor, detecting any deviation of the phase angle from a predetermined value established in accordance with the desired angular velocity of the engine, and controlling the duration of said pulses to minimize any deviation of the phase angle from said pr predetermined value; and detecting the angular velocity of said motor and producing a second signal proportional thereto, comparing said second signal with a predetermined value representing the desired motor speed and producing an output representing deviation of the angular velocity of said motor from the predetermined value, generating an excitation current, and applying said excitation current of said motor to said excitation coil while modulating the excitation current with said output representing deviation of said angular velocity.

Claim 9

A method of controlling the operation of a synchronous motor having an excitation coil and variable angular velocity from an alternating current line source, said method comprising the steps of: rectifying an alternating current input from said line source to produce a direct current; triggering a thyristor inverter with a train of pulses to connect the direct current to said motor during conductive periods of the thyristor inverter whereby said motor is driven at a rate determined by the frequency and duration of said pulses; deriving a first signal representing the phase angle of the angular velocity of the motor, detecting any deviation of the phase angle from a predetermined value established in accordance with the desired angular velocity of the engine, and controlling the duration of said pulses to minimize any deviation of the phase angle from said pr predetermined value; and detecting the angular velocity of said motor and producing a second signal proportional thereto, comparing said second signal with a predetermined value representing the desired motor speed and producing an output representing deviation of the angular velocity of said motor from the predetermined value, generating an excitation current, and applying said excitation current of said motor to said excitation coil while modulating the excitation current with said output representing deviation of said angular velocity.