Position-and-velocity sensorless control for starter generator electrical system using generator back-EMF voltage

Claims

We claim:

1. 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 which is supplied a parameter of AC power, comprising:

means coupled to the main generator portion armature phase windings for deriving a number of interval pulses relating to the revolution of the motive power shaft from a parameter of the AC power supplied to the main generator portion armature phase windings;

means coupled to the deriving means for measuring time periods between adjacent interval pulses; and

means coupled to the measuring means for converting the measured time periods into an indication of the angular position of the motive power shaft.

2. The detector of claim 1, wherein the measuring means comprises a counter which accumulates clock pulses during time periods between adjacent interval pulses.

3. The detector of claim 2, wherein the converting means includes means for inverting a counter output signal developed by the counter to obtain an indication of the speed of the motive power shaft.

4. The detector of claim 3, wherein the converting means further includes an integrator coupled to the inverting means which develops the angular position indication.

5. 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 are supplied a parameter of AC power during operation in the starting mode comprising:

means coupled to the main generator portion armature phase windings for deriving a number of interval pulses relating to the revolution of the motive power shaft from the parameter of AC power supplied to the main generator armature phase windings;

means coupled to the deriving means for measuring time periods between adjacent interval pulses;

means coupled to the measuring means for converting the measured time periods into indications of the speed and angular position of the motive power shaft; and

means coupled to the converting means for delivering AC power to the set of main generator portion armature phase windings in dependence upon the speed and angular position indications.

6. The starting system control of claim 5, wherein the delivering means comprises first means for developing an electrical angle command signal from the angular position indication, second means for developing a power control signal from the speed indication and an inverter responsive to the electrical angle command signal and the power control signal for delivering the AC power to the set of main generator portion armature windings.

7. The starting system control of claim 6, further including second means for converting the electrical angle command signal into a sine signal and a cosine signal and third means for converting the sine and cosine signals into three-phase signals.

8. The starting system control of claim 7, further including three zero crossing detectors each responsive to one of the three-phase reference signals for producing first, second and third inverter control signals, respectively, and an inverter controller responsive to the power control signal and coupled between the zero crossing detectors and the inverter which operates the inverter in accordance with the first, second and third inverter control signals and the power control signal.

9. The starting system control of claim 6, wherein the second developing means includes a first summer for summing a power reference with a signal indicative of the power produced by the inverter to produce a power error signal, means for conditioning the power error signal and means for limiting the conditioned power error signal to produce the power control signal.

10. The starting system control of claim 9, wherein the seco