uction to systems
Drive and control system of elevator: drag the elevator control system has gone from simple to complex processes. Currently used for elevator drive system are: single, double-speed AC motor driving system, stator variable voltage speed control driving system of AC motor, DC motor drag Silicon controlled excitation system of the generator, thyristor power drag system VVVF inverter variable voltage speed control driving system
Principle
Elevator control system hardware by a car wheel, Office doors, speed signal, PLC, inverter systems, inverter speed only completed features, and part is done by the PLC logic control. PLC is responsible for logic signals, in order to start and stop signal from the inverter and inverter will also own work State transportation to the PLC, forming two-way contacts. System configuration with the rotary encoder motor coaxial connection and PG card completed speed detection and feedback to form a closed-loop speed and position loop. In addition system must configure the braking resistor, when the elevator speed runs, regenerating power of the motor, inverter feedback electrical energy, inhibition of DC high voltage
System overview
AC motors have characteristic of compact structure, easy maintenance. Single and double-speed AC motor drive system with open loop control, line simple, low price, it is still widely used in the elevator. But its poor comfort, generally used on the freight elevator, elevator speed control this system at 1M/s. Poor comfort of AC dual-speed elevator, particularly reflected in the slowdown in the process. Eddy current brake, dynamic braking for the exchange of, inter alia, on the elevator, which can be satisfied with the comfort level of accuracy. In addition, the reverse brake, electromagnetic brake, also on the elevator. AC motor's stator voltage-regulating speed control system has been widely used abroad in the elevator, and China is gradually applied. This system uses Silicon-controlled closed loop speed control, coupled with the energy consumption or Eddy current brake, making it under the control of the elevator in large numbers to replace the small, low speed range DC and AC dual-speed elevator quickly. Good comfort, high leveling accuracy, while the cost is low compared to DC lift, simple structure, easy maintenance and elevator used to 2m/s the following.