PID controlled synchronous motor for power factor correction

In this paper, a synchronous motor controlled by a PID based on a PIC 18F452 microcontroller has been studied under three different working conditions using varying excitation currents. Due to the complexity of PID parameters such as integrative and derivative terms, their conversion to digital systems has proven difficult. Hence, the collection of errors in a specified time period has been multiplied be means of a sampling period rather than complex integral algorithms. The difference between the error rate and its previous value has been divided into a sampling period to obtain the derivative operation. Therefore, a PID controlled algorithm has been embedded into a microcontroller which is easily implemented without complex algorithms. In addition, the design of this study includes an LCD based visual interface, allowing users to instantly monitor the current, the voltage and the power factor of the synchronous motor.