Patent ID: 6661206
Filing Date: 2003-12-09
Classification: H02P

Abstract:
An apparatus for controlling a switched reluctance machine, wherein the switched reluctance machine includes a plurality of rotor and stator poles and a plurality of phase windings on one or more of the stator poles, and wherein the switched reluctance machine is responsive to a voltage bus, said apparatus comprising:for each phase winding: a first switch connected between a first terminal of the voltage bus and a first terminal of the phase winding; a second switch connected between a second terminal of the voltage bus and a second terminal of the phase winding; a first unidirectional conduction device having a first terminal connected to the first terminal of the voltage bus and a second terminal connected to the second terminal of the phase winding, wherein said first unidirectional conduction device conducts current only in the direction from the second terminal to the first terminal thereof; a second unidirectional conduction device having a first terminal connected to the first terminal of the phase winding and a second terminal connected to the second terminal of the voltage bus, wherein said second unidirectional conduction device conducts current only in the direction from the second terminal to the first terminal thereof; wherein during at least a portion of the time when the rotor and stator poles are approaching, each of said first and second switches are closed and current flows from the first terminal of the voltage bus through the serial connection of said first switch, the phase winding and said second switch; wherein when the phase winding current is at a first predetermined value while the inductance of the rotor and stator poles of the phase winding is decreasing, opening said first and second switches, such that current flows from the second terminal of the voltage bus serially through said second unidirectional conduction device, from the first to the second terminals of the phase winding and through said first unidirectional conduction device to the first terminal of the voltage bus, after which the phase winding current begins to decrease; wherein when the phase winding current is at a second predetermined value, closing said first switch such that current flows through a short circuit loop comprising said first switch, the phase winding and said first unidirectional conduction device, after which the phase winding current begins to increase; wherein when the phase winding current is at the first predetermined value, opening said first switch such that the current flows from the second terminal of the voltage bus serially through said second unidirectional conduction device, from the first to the second terminals of the phase winding and through said first unidirectional conduction device to the first terminal of the voltage bus, after which the phase winding current begins to decrease; wherein the phase winding current changes between the first and second predetermined values until the inductance between the rotor and stator poles reaches a minimum value.