Abstract: An improved commutation control method precisely controls commutation in a switched reluctance machine with a relatively low resolution position encoder and a low cost micro-processor based controller. The control method involves the formation of a motor position signal having logic level transitions, or edges, that define base commutation signals for commutating the motor phase windings in sequence with no phase advance. When no phase advance is desired, the controller turns the phase windings on and off in time with the respective base commutation signals. When phase advance is desired, the controller turns each of the windings on and off relative to the base commutation signal for the preceding phase winding. More specifically, the turn-on and turn-off points for phase advance control are timed to occur a delay time after the edges of the base commutation signal for the preceding phase.

Abstract: A software-controlled latched voltage regulator includes three bipolar transistors responsive to a wiper switch multiplexed signal to place a latch formed by the transistors in an energized state, thereby supplying power to a microcontroller. One of the bipolar transistors is responsive to a deenergization signal supplied by the microcontroller, under software control, to place the latch in a deenergized state wherein regulated power is no longer supplied to the microcontroller. The voltage regulator further includes a zener diode that provides a reference voltage for use in connection with one of the transistors to implement a decoding function that is applied to the switch multiplexed signal to provide a pair of wiper switch position signals for use by the microcontroller during operation. While the latch remains in an energized state, the supplied regulated voltage enables the microcontroller to park a wiper arm of a wiper system, even though an ignition switch is an off position.