Speed sensorless induction motor drive with PCC in conveyor systems

Conveyor systems allow quick and efficient transportation for a wide variety of materials, which make them very popular in the material handling and packaging industries. Many kinds of conveying systems are available and used according to the various needs of different industries. Adjustable speed drives are used for the operation of the conveyors used in a number of industries. We can use adjustable electric drives in a number of industrial applications. A typical adjustable speed drive consists of an induction motor and a power electronic converter. In most cases, motor speed is commanded so that the control system requires an actual speed signal for closing the speed loop. In industrial applications, speed sensors, as well as sensorless solutions, are used. Due to the possibility of current speed sensor noises and for maintenance and economic aspects, the trend is to substitute speed sensors by computational solutions. Comprehensive reviews of the sensorless drives show that there are still some persistent problems associated with the sensorless control, that needs new solutions. In ASDs, the advanced control approach of IM is the FOC method, used in modern industrial drives. The current stator controller is the integral part of various FOC systems. In the classical FOC solution, PI or hysteresis controllers are generally used. However, PCCs are reported to have better properties. System sensitivity to inaccuracy and changes of motor equivalent circuit parameters are another problem in electrical drives. Almost all of the FOC systems are very sensitive to such inaccuracies; therefore, some parameters should be estimated online, and a robust structure of the control is required. The real-time implementation of the system is an important task even for electric drives or power converters.