Seiya Shima

A New Speed Control System for DC Motors Using GTO Converter and its Application to Elevators

A dc motor control system using a new GTO converter, is developed for an intermediate-speed elevator (2.5-m/s rated speed and 1000-kg load). Its features include 1) a main circuit control system composed of pulsewidth and phase controls, 2) a circuit to suppress the overvoltage which occurs when the GTO is turned off, 3) direct digital control which is composed of an acceleration control to compensate for lag time in the field current response and a self-correcting function to compensate for landing error. Application of the control system provided a higher power factor and smaller power consumption than a conventional control system.

High-speed elevators controlled by sinusoidal current source inverters

The authors, et al. have developed newly such a current source inverter technology that the input/output voltage and current are all controlled sinusoidally by microcomputers PWM control function and in addition, power regenerating function is permitted and then have applied it effectively to high-speed elevators.

A New Speed-Control System for DC Motors and its Application to Elevators

A circuit with a unidirectional armature current and bidirectional field current was used in order to realize a high-reliability speed-control system for dc motors by simplifying the armature circuit construction in comparison with conventional Thyristor-Leonard speed-control systems. In making the new circuit feasible, we developed a system in which either armature current or field current is fixed and the other varies depending on the magnitude of the torque command; a high-reliability magnetically controlled three-phase thyristor amplifier; and minor feedback loops provided with a field current control circuit and armature current control circuit. By using these techniques, we developed a dc motor control system that features higher reliability and smaller power consumption than conventional control systems. The new system was applied to elevator control with good results.

Development of high-speed AC elevator control with thyristors

The high-speed AC elevators with a speed of 105 mpm (350 fpm) were developed by applying thyristors to their control. The acceleration of the elevators is controlled by two-phase primary voltage control of AC motor, while their deceleration is regulated by DC braking through thyristor convertor. The new technology to enable continuous torque control from motoring to braking has been developed by the Push-Pull characteristics of the control for the higher and lower speed motors. Thus, complex DC motor and motor-generator were replaced by simple AC motor and economical control system was realized.