Rotor position detector with back EMF voltage estimation
AssigneeSundstrand Corporation
InventorsGregory I. Rozman, Vijay K. Maddali, Albert L. Markunas
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Abstract
A detector for detecting rotor position of a brushless generator having a motive power shaft and a main generator portion having a set of armature phase windings capable of receiving AC power and developing a back EMF voltage during operation in a starting mode, includes a circuit coupled to the set of armature phase windings and capable of responding to the AC power for producing a back EMF estimate signal representing an estimate of the back EMF voltage. The detector also includes a circuit for converting the back EMF estimate signal into an indication of the angular position of the motive power shaft.
Claims36
A detector for detecting rotor position of a brushless generator having a motive power shaft and a main generator portion having first and second main generator portion armature phase windings capable of receiving AC power add developing a back EMF voltage during operation in a starting mode, comprising:
- means coupled to the first and second main generator portion armature phase windings and capable of responding to the AC power for producing a back EMF estimate signal representing an estimate of the back EMF voltage, said producing means including;
- first means responsive to currents developed in said first and second main generator portion armature phase windings for developing a current magnitude signal;
- second means responsive to voltages developed at the first and second main generator portion armature phase windings for developing a line-to-line voltage signal;
- and
- means responsive to the current magnitude signal and the line-to-line voltage signal for deriving the back EMF estimate signal;
- and
- means for converting the back EMF estimate signal into an indication of angular position of the motive power shaft.
A detector for detecting rotor position of a brushless generator having a motive power shaft and a main generator portion having a set of armature phase windings capable of receiving AC power and developing a back EMF voltage during Operation in a starting mode, comprising:
- mean coupled to the set of armature phase windings and capable of responding to the AC power for producing a back EMF estimate signal representing an estimate of the back EMF voltage;
- and
- means for converting the back EMF estimate signal into an indication of angular position of the motive power shaft, said converting means including a phase-locked loop comprising:
- a first zero crossing detector responsive to the back EMF estimate signal,
- a second zero crossing detector responsive to the indication of the angular position of the motive power shaft,
- a phase detector coupled to the first and second zero crossing detectors, and
- means coupled to the phase detector for obtaining the indication of the angular position of the motive power shaft.
A starting system control for operating a brushless generator in a starting mode to convert electrical power into motive power wherein the brushless generator includes a motive power shaft and a main generator portion having a set of armature phase windings which receive AC power and in which a back EMF voltage is induced during operation in the starting mode, comprising:
- means coupled to the set of armature phase windings and responsive to the AC power for producing a back EMF estimate signal representing an estimate of the back EMF voltage;
- means for converting the back EMF estimate signal into indications of a speed and angular position of the motive power shaft;
- and
- means coupled to the converting means for delivering AC power to the set of armature phase windings in dependence upon the speed and angular position indications, said delivering means comprising:
- first means for developing a torque command signal and an electrical angle command signal from the speed and angular position indications, and
- an inverter responsive to the torque command signal and the electrical angle command signal which develops the AC power.
A starting system control for operating a brushless generator in a starting mode to convert electrical power into motive power wherein the brushless generator includes a motive power shaft and a main generator portion having first and second main generator portion armature phase windings which receive AC power and in which a back EMF voltage is induced during operation in the starting mode, comprising:
- means coupled to the first and second main generator portion armature phase windings and responsive to the AC power for producing a back EMF estimate signal representing an estimate of the back EMF voltage, said producing means including first means responsive to the current flowing in said first and second main generator portion armature phase windings for developing a current magnitude signal, second means responsive to the voltages on the first and second main generator portion armature phase windings for developing a line-to-line voltage signal and means responsive to the current magnitude signal and to the line-to-line voltage signal for deriving the back EMF estimate signal;
- means for converting the back EMF estimate signal into indications of speed and angular position of the motive power shaft;
- and
- means coupled to the converting means for delivering AC power to the first and second main generator portion armature phase windings in dependence upon the speed and angular position indications.
A method of detecting rotor position of a brushless generator having motive power shaft and a main generator portion having first and second main generator portion armature phase windings which receive AC power and which develop a back EMF voltage during operation in a starting mode, the method comprising the steps of:
- estimating the back EMF voltage developed at the first and second main generator portion armature phase windings to produce a back EMF estimate signal, said estimating steps comprising the steps of;
- combining signals representing currents flowing in said first and second main generator portion armature phase windings to develop a current magnitude signal,
- combining signals representing the voltages developed at the first and second main generator portion armature phase windings to develop a line-to-line voltage signal and
- deriving the back EMF estimate signal from the current magnitude signal and the line-to-line voltage signal;
- converting the back EMF estimate signal into an indication of angular position of the motive power shaft;
- and
- delivering AC power to the first and second main generator portion armature phase windings in dependence upon the angular position indication.
A method of detecting rotor position of a brushless generator having a motive power shaft and a main generator portion having a set of armature phase windings which receive AC power and which develop back EMF voltage during operation in a starting mode, the method comprising the steps of:
- estimating the back EMF voltage developed at the set of armature phase windings to produce a back EMF estimate signal;
- and
- converting the back EMF estimate signal into an indication of angular position of the motive power shaft, said converting step including the steps of deriving a number of interval pulses per revolution of the motive power shaft from the back EMF estimate signal, measuring time periods between adjacent interval pulses and converting the measured time periods into the indication of the angular position of the motive power shaft.
A back EMF voltage estimator for use in a brushless generator having a motive power shaft and a main generator portion having first, second and third armature phase windings capable of receiving AC power with a flow of current therethrough and generating a line-to-line voltage therebetween and capable of developing a back EMF voltage during operation in a starting mode, comprising:
- first means responsive to currents flowing in the first and second armature phase windings for developing a current magnitude signal;
- second means responsive to voltages developed at the first and second armature phase windings for developing a line-to-line voltage signal;
- and
- means responsive to the current magnitude signal and to the line-to-line voltage signal for deriving the back EMF estimate signal.
A back EMF voltage estimator for use in a brushless generator having a motive power shaft and a main generator portion having first, second and third armature phase windings capable of receiving AC power and capable of developing a back EMF voltage during Operation in a starting mode, comprising:
- first means responsive to currents flowing in the first and second armature phase windings for developing a current magnitude signal;
- second means responsive to voltages developed at the first and second armature phase windings for developing a line-to-line voltage signal;
- third means for developing current estimate signal;
- and
- means responsive to the current magnitude signal and to the line-to-line voltage signal for deriving the back EMF estimate signal the deriving means including a first summer for subtracting the current magnitude signal from the current estimate signal to produce a first output signal, a first conditioner for conditioning the first output signal to produce the back EMF estimate signal, a combiner for combining the current estimate signal, the back EMF estimate signal and the line-to-line voltage signal to produce a second output signal, said third means responsive to the second output signal for developing the current estimate signal.
Dependencies are inferred from the claim text.