ABSTRACT

Reliable rotor position measurement is quite necessary for ensuring accurate commutation control in many kinds of motor drives, such as switched reluctance motor (SRM) and brushless DC motor (BLDC). Traditionally, the hall sensors and photoelectric switch sensors are widely used in most of those low-cost motor drive systems. In these systems, the rotor position needs to be decoded from the discrete voltage pulses measured by the sensors. Thus, to develop an online position pulse signals fault diagnosis scheme with fast fault monitoring capability is quite vital for avoiding the abnormal driving control and improving the overall system reliability. In this Project, a position pulse signal fault diagnosis scheme based on synthetic hybrid-integral threshold logic is proposed for SRM drives. In this method, the complementary position pulse signals of each sensor are used as the independent reference signals. By applying special integral calculations on each reference signals and capturing their rising and falling edges respectively, the position pulse fault cases like high-level and low-level faults can be diagnosed immediately with the synthetic thresholds comparison logic. To verify the validity of the proposed method, a 1kW 12/8 structure SRM prototype with three independent hall sensors installed is used as a test machine. This method can diagnose the position fault of each position sensor independently and ensure very fast position fault detection even under dynamic operations with speed transients. Furthermore, the method can be implemented without additional hardware and complex computation, which is quite suitable for constructing a reliable position measurement module to assist the rotor position sensors.