Abstract: A switched reluctance drive includes a reluctance machine, a controller, power switches actuated by the controller and a current transducer for monitoring the current in each phase winding. The controller employs a sensorless rotor position detection technique by injecting voltage pulses into the idle period of each phase winding in a chopping mode. Acoustic noise associated with the injected pulses is concealed by varying the frequency at which the pulses are injected according to rotor speed. In an alternative embodiment the frequency is varied pseudo-randomly.

Abstract: A polyphase switched reluctance machine controlled by a control system using sensorless position detection. The controller is robust and reliable and operates over the entire speed range of the machine. In the chopping mode, diagnostic pulses of predetermined flux linkage are injected into an idle phase. In the single-pulse mode, position prediction is done using an active phase. A method of starting the machine uses diagnostic pulses in two phases to provide a unique value for position, allowing the drive to start or re-start under full torque.

Abstract: A polyphase switched reluctance machine is controlled by a control system using sensorless position detection. A method of operating the machine at high speeds interrogates every nth phase reference point to allow sufficient time for computations of position to be carried out, where n is an integer greater than one.