Abstract: A current-type converter including a DC power source, a current-type converter, a load and a converter control unit, the converter control unit controlling so as to cause as least two states among a powering conduction state for supplying power from said DC power source to said load within predetermined control periods of both a powering control mode and a regenerative control mode, a regenerative conduction state for regenerating power supplied from the load toward the DC power source, and a reflux conduction state for short-circuiting the output of the current-type converter and returning the circuit current of the load, and the converter control unit varying the period length of respective states.

Abstract: An elevator control apparatus comprises an inverter device for supplying an induction motor for driving an elevator cage with AC electric power of variable voltage and frequencies and control equipment for controlling the output voltage and frequencies of the inverter device in response to signals produced in floors served by the elevator and in an elevator cage. The inverter device is constructed by a converter unit for converting AC electric power to DC electric power, at the input end of which a capacitor is connected in parallel with an AC electric source, an inverter unit for inverting the DC electric power converted in the converter unit into AC electric power, at the output end of which a capacitor is connected in parallel with an induction motor for driving the elevator cage and a DC reactor connected between the converter unit and the inverter unit.The thus constructed elevator control apparatus does not cause interference in electric appliances such as audio equipment, computer etc.

Abstract: An inverter, which supplies an induction motor for driving an elevator with DC power, is controlled by means of a vector control method. A rotating angular speed of the induction motor is detected from a torque component of a detected motor current. A present position of an elevator cage is calculated on the basis of the detected rotating angular speed.

Abstract: In a controller for an AC elevator in which the frequency of AC power applied to a driving induction motor is varied by a frequency converter, the output frequency of the frequency converter when the elevator is running at its rated speed is at least as high as the frequency of the AC supply, and the AC supply is applied directly onto the induction motor without any frequency conversion during low-speed running, so that the elevator can be run slowly without using the frequency converter.

Abstract: In an AC elevator system employing a three-phase induction motor for driving an elevator car, the primary voltage supplied to the induction motor is controlled to control the motoring torque in the acceleration mode and in the rated-speed running mode, while, in the deceleration mode, a power converter unit supplies AC power of low frequency to the induction motor to apply regenerative braking.

Abstract: A control system for an AC elevator system in which an actual speed of an elevator car is compared with a speed command and control is made so that deviation between the actual speed and the commanded speed becomes zero. The speed command is so composed that deceleration of the elevator car is gradually decreased as the car approaches to a target landing position in the stopping operation of the elevator. A motoring torque or a braking torque is additionally generated in dependence on a load on the car in a region close to the target landing position.

Abstract: In a three phase load controlling system two bilateral switching circuits control the current in the first and the third phases; the first phase is later than the third. The second phase is uncontrolled. The gating signals applied to the bilateral switching arrangement connected in the first phase are advanced by a constant degree with respect to the voltage of the first phase. The gating signals applied to the bilateral switching arrangement connected in the third phase are synchronized with the voltage of the third phase.

Abstract: A phase control apparatus is disclosed wherein a pair of transistors are alternately switched by an A.C. signal source. Each of the transistors is connected in series with an auxiliary thyristor and a primary winding of a pulse transformer to a D.C. power supply. Each of the auxiliary thyristors is fired by a magnetic phase shifter having an A.C. winding connected between a positive terminal of the D.C. power supply and a gate of the auxiliary thyristor. Connected to secondary windings of the pair of pulse transformers are gate circuits of a pair of main thyristors to which an A.C. voltage which is substantially in synchronism with the A.C. signal source is applied.

Abstract: In an a-c elevator, an elevator car suspended by ropes is driven by an induction motor for vertical movement. A system commonly used for controlling the device including thyristors connected in parallel with opposite polarities across a three-phase a-c power source and the induction motor for controlling the motoring torque produced by the induction motor, a bridge rectifier including a thyristor for supplying direct current to the induction motor for controlling the braking torque produced by the induction motor, and means for controlling the operating phase of the thyristors in the thyristor device and the thyristor in the bridge rectifier depending on the error between the instructed speed and the actual speed of the elevator car.

Abstract: A magnetic phase shifter utilizing the principle of magnetic amplifier is used as a phase shifter for applying a firing signal to a main thyristor. In order to amplify and sharpen the rise of the output pulse of the magnetic phase shifter, an auxiliary thyristor is fired by the output pulse of the magnetic phase shifter. The gate-cathode circuit of the main thyristor is connected to the auxiliary thyristor as a load thereof. Power for the auxiliary thyristor is obtained from an AC power supply which is in phase with the main thyristor through a transformer, while power for the magnetic phase shifter is introduced from an intermediate tap of the secondary winding of the transformer, thus making the magnetic phase shifter compact as well as low in cost.