Low-Speed Position-Sensorless Control of SRM Drives Using Random Frequency Pulse Injection for Noise Reduction

This paper proposes a new pulse injection scheme for low-speed position-sensorless switched reluctance motor (SRM) with audible noise reduction. Constant injection frequency is used in conventional injection methods for position estimation, which causes the motor to produce noise corresponding to the injection frequency. In order to solve this problem, a random frequency pulse injection(RFPI) scheme is proposed. By generating random injection frequency in each injection cycle and calculating duty cycle of injection pulse, the induced current is kept at a minimum while the noise generated by pulse injection is reduced. Finally, the effectiveness of the proposed position-sensorless control scheme is verified on a 6/4 SRM setup.