Speed measurement of synchronous generator without tachometer and its application

This paper presents a practical approach for the speed measurement of synchronous generator without the speed sensor using single chip of micro\|controller PIC16C57. By means of the peripherals of PIC16C57, the width of the phase\|voltage of the generator will be identified, which can be used as a basis for the speed estimation of the prime motor, hence, the tachometer can be removed so as to avoid the necessary assembly and calibration of the speed sensor, simplify the peripherals of the PIC16C57, and reduce the system cost as well. The reliability of the protection circuit can be correspondingly enhanced by means of preventing the self\|excitation synchronous generator with thyristor\|based field\|excitation circuit from low\|speed operation, which has been evaluated by a case of application.