PLC-based AC VVVF Elevator Control System Design

Along With the lift drag and control technology fast development, Elevator already from dc motor drive to exchange single speed. From the AC voltage speed (ACVV, AC Variable Voltage) regulation control development to Variable Voltage Variable frequency modulation technology( VVVF, Variable Voltage Variable Frequency ) control. Makes the elevator running reliability, safety, comfort, flat layer precision, operation speed, saving energy and reducing consumption, and reduce the noise from the great development. VVVF elevator complies with the ideal elevator running curve,and the motor is accurately adjusted by the vector control software, and the elevator stable operation. However, real-time control effect is not ideal.VVVF for this shortcoming, This paper puts forward a kind of adaptive control algorithm which uses a based on continuous input/output domain of the fuzzy controller to Avoid the common errors of PID control the way not too reasonable and the introduction of error integral feedback have many negative effect linear combination is not necessarily the best combination shortcomings, to adapt VVVF system when the degeneration, further improve the control precision of the system. The simulation results show that, based on fuzzy control real-time speed regulation system elevator good robustness and high control accuracy.Finally, realized based on fuzzy control VVVF system, First, make sure the overall structure of the system, by PLC to realize the signal control, frequency converter realize frequency control, complete frequency converter and programmable controller (PLC) choice. Then realized the system hardware development, complete inverter parameter and PLC of the selection of the I / 0 points distribution and rotary encoder and PLC connection. And on the analysis of the system based on the design method of software, design the software flow chart, modular programming. After the reconstruction of the elevator system simulation test .Debugging results show that by using a kind of based on continuous input/output domain of the fuzzy controller, to avoid the common fuzzy controller because of domain discretize existing quantizing errors. Through use the hierarchical fuzzy control method to improve the control precision of the system and convergence quality. At the same time it gives an adaptive control algorithm, using it can adjust the fuzzy rules in order to adapt to the system of time-varying. The fuzzy controller for a typical nonlinear time-varying systems VVVF elevator real-time control of the result shows that the fuzzy controller high control accuracy, adaptive ability, has the very high practical value.