CONTROL AND DATA ACQUISITION OF AC MOTOR WITH ZIGBEE TECHNOLOGY

Abstract

In this project, a wireless control and monitoring system for an AC motor is realized using the Zigbee communication protocol for safe and economic data communication in industrial fields where the wired communication is either more expensive or impossible due to physical conditions. The induction motor can be started and stopped wireless due to the computer interface developed with Zigbee. It is also possible to protect of the motor against some faults such as over current, higher/lower voltage, over temperature in windings, overloading of motor. Moreover, a database is built to execute online measurements and to save the motor parameters received by radio frequency (RF) data acquisition system. Therefore, controlling, monitoring, and protection of the system are realized in real time. Since the wireless communication technology is used in this study, controlling abilities of the system are increased and also hardware and the necessities of other similar equipment for data communication are minimized.
Wireless sensor networks have been very popular research field for the couple of years. ZigBee is a newly developed technology now being deployed for wireless sensor networks. ZigBee is a low data rate wireless network standard defined by the ZigBee Alliance and based on IEEE 802.15.4. The ZigBee wireless network has some advantages compared with other wireless networks, it has the characteristics of low power, low price, highly secured and reliable, so implementing a remote control and monitoring system proves to have a good cost performance ratio. This project presents the implementation of wireless sensor actor network (point to point) to control the speed of a AC Motor from a remote location. Varying speed of AC motor by means of changing firing angle of any thyristor is very widely used method. A zero crossing detector circuit is used here to interrupt ATMEGA AVR16 after every 10 ms. After getting an interrupt ATMEGA AVR16 will fire TRIAC after some delay from 1 to 9 ms. This will cut the current supplied to motor and so the speed of motor will reduce. Thus by varying the delay after which the TRIAC is triggered one can change the speed of motor. The speed sensing could be done by sensing and providing feedback with help of Tachogenerator .This paper also provides a provision for sensing the temperature, which is a crucial parameter of the motor, by using the facility of Thermister Sensing technology.