Abstract: A motor control system controls to be constant a reactive power consumed by a motor load equipment having a motor to be driven by power supplied from an AC power source and a couple of thyristor converters for regulating the power supplied to the motor. To this end, the motor control system is comprised of a reactor power detector for detecting the reactive power of the motor load equipment, a command circuit for issuing a command to specify the rated reactive power consumed in the rated load running of the motor load equipment, and a reactive power control unit which receives an output signal from the command circuit and an output signal from the reactive power detector to produce a firing phase command signal depending on a difference between them. The firing phase command signal from the reactive power control unit is applied to an automatic pulse phase shifter to control the firing phase of the thyristor converters.

Abstract: An electric control apparatus of an induction motor is provided with a flux current controller for controlling the flux current of the motor and a secondary current controller for controlling the secondary current of the motor. A pulse generator circuit is disposed to control the amplitude, frequency and phase angle of the primary current of the motor according to output signals of the flux current controller and secondary current controller. The primary voltage and frequency to be applied to the motor are controlled by pulse signals from the pulse generator circuit. This pulse generator circuit includes a primary voltage setting zone for setting the primary voltage of the induction motor and a primary voltage detecting zone for detecting the primary voltage of the motor.

Abstract: A first PWM inverter for converting the ac voltage of an ac power source to a dc voltage is connected through a dc circuit with a second PWM inverter for driving an ac motor. A smoothing capacitor is provided in the dc circuit. The firing angles of the first inverter are so controlled that the voltage in the dc circuit may be kept at a predetermined value and the second inverter is controlled in accordance with the speed instruction signal for the ac motor, whereby the ac motor can operate a regenerative operation without inducing higher harmonic components.

Abstract: A control apparatus of a synchronous motor having armature windings and perpendicular field windings comprises a frequency converter of a cycloconverter which converts the frequency of an alternating current and supplies the converted current to the armature windings of the synchronous motor. On a shaft of the synchronous motor are installed a speed detector, a position detector, and a speed instruction circuit. The frequency converter is controlled in accordance with the outputs of the speed detector, the position detector and the speed instruction circuit. An alternating current excites the field windings, so that a field of magnetic force is rotationally generated. The direction of the magnetic field is determined depending upon the output of the speed detector.

Abstract: An induction motor has a multi-phase primary winding (stator winding) and a multi-phase secondary winding (rotor winding) which are connected to each other in opposite phase relation. The both windings are fed with variable frequency A.C. current from a common frequency converter. A position sensor for sensing a rotor position is mounted on the induction motor. The position signal of the position sensor is in phase with an air gap flux between the primary winding and the secondary winding. Magnitude of a motor current is controlled in accordance with a torque command signal indicative of an error between a speed command signal and a speed feedback signal and with a voltage command signal for determining a terminal voltage, and a phase difference of the motor current relative to the position signal is controlled in accordance with the torque command signal and the voltage command signal.

Abstract: A control device for a thyristor motor is disclosed by which the advance angle is switched at a predetermined slow rate of change in order to avoid an abrupt change in the motor torque. The thyristor motor comprises a thyristor frequency converter for a frequency conversion and a synchronous motor driven by the frequency converter, and in the thyristor motor the advance angle is switched at low and high speeds of the motor.

Abstract: A synchronous motor having multi-phase armature windings and a field winding is drived by a frequency converter. Actual torque is determined from a sinusoidal position signal representative of rotational position of the synchronous motor and the armature current. The actual torque value is compared with a command torque signal, whereby the armature current is controlled in dependence on difference or deviation resulting from the comparison thereby to cancel the torque ripple. Torque ripple can thus be suppressed to a satisfactory degree even at a low rotation speed of the synchronous motor.

Abstract: An AC motor has polyphase stator windings connected to an AC bus and has polyphase rotor windings connected directly or through impedances to capacitors. The capacitances of the capacitors are selected so as to be such that the AC motor exhibits a small input impedance for a specific frequency to be eliminated, thereby preventing the power factor from being since the fundamental frequency is not affected in any way under a light load. As a result, harmonics can be eliminated without causing any excessive AC source voltage.

Abstract: A control system for an a.c. motor having a polyphase primary winding (stator winding) and a corresponding polyphase secondary winding. The primary and the secondary windings are supplied with current from different frequency converters provided separately for each of the windings. The alternating currents flowing through the primary and the secondary windings are in opposite phase with each other. A position detector is provided for detecting the position of rotor of the a.c. motor. The magnitude of the primary current is controlled proportionally to a current reference signal in dependence on deviation of a speed feed-back signal from a speed reference signal, while the magnitude of the secondary current is controlled to a constant value. The phases of the primary and the secondary currents are controlled on the basis of the rotor position.

Abstract: A control apparatus for use in a synchronous machine having a field and an armature windings, one of the windings being provided on a stator and the other winding on a rotor comprises a thyristor converter for feeding the armature winding with electric power. A rotor position detector, an actual current detector and a rotating speed detector are provided. A current pattern signal is produced on the basis of the rotor position signal and the rotating speed signal and is compared with the actual armature current. A gate pulse generator controls the thyristors of the thyristor converter in accordance with the difference between the current pattern signal and the actual armature current signal. A phase shifter is provided for shifting the current pattern signal. A phase detector detects the phase difference between the armature current supplied for the armature winding and the rotor position, and the phase shifting operation of the phase shifter is controlled in accordance with an output from the phase detector.

Abstract: A control system for a commutatorless motor, comprising a synchronous motor having a polyphase armature winding and a field winding; a frequency converter for supplying the armature winding with alternating current having a variable frequency; an angular position detector for detecting the angular position signal corresponding to the angular position of the rotor of the synchronous motor; a speed control circuit for delivering a current reference signal having an amplitude corresponding to the deviation of the actual speed of the synchronous speed from the reference speed; a current control circuit for controlling the amplitude of the output current of the frequency converter in accordance with the current reference signal and for maintaining the amplitude of the output current of the frequency converter constant in the range where the torque reference signal assumes a value smaller than the intermittent threshold of the armature current; and a phase control circuit for controlling the phase of the output cur

Abstract: A control system for commutatorless motor comprising a synchronous motor having a multi-phase armature winding and field winding, a frequency converter for supplying a-c current of variable frequencies to the armature winding, a position detector for detecting the position signal based on the rotational position of the synchronous motor, a voltage setting circuit for producing a constant exciting reference signal for determining the magnitude of the terminal voltage of the synchronous motor, a first operational circuit for determining the magnitude of the nominal induced electromotive force representing the vector sum of the armature reaction drop and terminal voltage on the basis of the signal proportional to the armature current and constant exciting reference signal, a second operational circuit for obtaining the phase difference between the nominal induced electromotive force and terminal voltage obtained from the first operational circuit, a field control means for controlling, the field constant current

Abstract: A control system for a brushless motor is disclosed which comprises an AC power supply, a rectifier circuit including controlled rectifier elements for converting the alternating current supplied by the AC power supply into a direct current, an inverter circuit including controlled rectifier elements for converting the direct current produced by the rectifier circuit into an alternating current, a motor driven by the inverter circuit and a position detector for detecting a signal representing rotational positions of the motor. The controlled rectifier elements of the inverter circuit are fired in predetermined sequence in response to detection signals from the position detector, while the DC output current of the rectifier is continually controlled at each commutation of the inverter circuit at low motor speeds.