Indirect rotor position sensor for a sinusoidal synchronous reluctance machine

Claim 1

A method of detecting rotor position in a rotating sinusoidally excited synchronous reluctance electric machine having multiple stator phases which are energized by sinusoidal currents at an excitation frequency in all phases comprising the steps of: interrupting the excitation to a first phase at a zero crossing for that phase current for a predetermined period of time to create a zero crossing window thereby enabling the reading of the induced voltage in the disconnected phase; simultaneously coupling the other phases to sinusoidal excitation for the same period of time; reading the induced voltage in the first phase; detecting the phase currents in the other phases; and calculating the rotor position from the read induced voltage, detected phase current, and the excitation frequency.

Claim 2

A method of detecting rotor position in a rotating sinusoidally excited synchronous reluctance electric machine having multiple stator phases which are energized by sinusoidal currents at an excitation frequency in all phases comprising the steps of: interrupting the excitation to a first phase at a zero crossing for that phase current for a predetermined period of time to create a zero crossing window thereby enabling the reading of the induced voltage in the disconnected phase; simultaneously coupling the other phases to sinusoidal excitation for the same period of time; reading the induced voltage in the first phase; detecting the phase currents in the other phases; and calculating the rotor position from the read induced voltage, detected phase current, and the excitation frequency.

Claim 3

A method of determining rotor position in a sinusoidally excited, multi-phase synchronous reluctance machine at stand-still, comprising the steps of: energizing a phase pair with a diagnostic signal to develop a diagnostic current; detecting the diagnostic current; determining the rate of change of the diagnostic current to determine the slope of the diagnostic current; reading the induced voltage off another phase; and using the read induced voltage and the slope of the diagnostic current to determine the rotor position at stand-still.

Claim 4

A method of determining rotor position in a sinusoidally excited, multi-phase synchronous reluctance machine at stand-still, comprising the steps of: energizing a phase pair with a diagnostic signal to develop a diagnostic current; detecting the diagnostic current; determining the rate of change of the diagnostic current to determine the slope of the diagnostic current; reading the induced voltage off another phase; and using the read induced voltage and the slope of the diagnostic current to determine the rotor position at stand-still.

Claim 5

A device for determining the position of a rotor in a rotating, sinusoidally excited synchronous reluctance machine comprising: a. a plurality of switches for selectively coupling the stator windings to a source of sinuosidal electrical excitation; b. a driver to selectively de-couple one phase of the stator windings from the source of excitation and to couple the remaining phases of the stator windings to the source of excitation; c. a voltage sensor to sense the voltage induced in the stator windings de-coupled from the source of excitation and to output a sensed voltage; d. a current sensor to sense the current in the coupled windings and to output a sensed current; e. means for determining the rate of change of the current sensed by the current sensor and to output a current slope; f. means for determining the frequency of rotation of the rotor; and g. means for determining the rotor position from the sensed voltage, the sensed current, the current slope, and the frequency of rotation.

Claim 6

A device for determining the position of a rotor in a rotating, sinusoidally excited synchronous reluctance machine comprising: a. a plurality of switches for selectively coupling the stator windings to a source of sinuosidal electrical excitation; b. a driver to selectively de-couple one phase of the stator windings from the source of excitation and to couple the remaining phases of the stator windings to the source of excitation; c. a voltage sensor to sense the voltage induced in the stator windings de-coupled from the source of excitation and to output a sensed voltage; d. a current sensor to sense the current in the coupled windings and to output a sensed current; e. means for determining the rate of change of the current sensed by the current sensor and to output a current slope; f. means for determining the frequency of rotation of the rotor; and g. means for determining the rotor position from the sensed voltage, the sensed current, the current slope, and the frequency of rotation.

Claim 11

A device for determining the position of a rotor in a rotating, sinusoidally excited, multi-phase, synchronous reluctance machine comprising: a. means for interrupting the excitation in a first phase of the stator windings to develop a zero-crossing window; b. a voltage sensor to sense the voltage induced in the stator windings in the first phase; c. a current sensor to sense the current in another phase; d. means for determining the rate of change of the current sensed by the current sensor and to output a current slope; e. means for determining the frequency of rotation of the rotor; and f. means for determining the rotor position from the sensed voltage, the sensed current, the current slope, and the frequency of rotation.

Claim 12

A device for determining the position of a rotor in a rotating, sinusoidally excited, multi-phase, synchronous reluctance machine comprising: a. means for interrupting the excitation in a first phase of the stator windings to develop a zero-crossing window; b. a voltage sensor to sense the voltage induced in the stator windings in the first phase; c. a current sensor to sense the current in another phase; d. means for determining the rate of change of the current sensed by the current sensor and to output a current slope; e. means for determining the frequency of rotation of the rotor; and f. means for determining the rotor position from the sensed voltage, the sensed current, the current slope, and the frequency of rotation.