Method and system for determining crankshaft position in an electrical generating system
AssigneePegasus Aeronautics Corporation
InventorsMatthew Mcroberts, Joseph Kinsella
Life of this patent
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Abstract
A system and method are disclosed for determining the mechanical angular position of a rotating member of a prime mover which is connected, directly, or indirectly, to an electric machine, such as a permanent magnet synchronous machine or an induction machine. The electrical angular position of the rotor of the electric machine is determined by a sensorless AC motor control system, such as a Field Oriented Control System or back EMF control system, and is used in turn to determine the mechanical angular position of the rotating member.
Claims19
An electrical generating system comprising:
- a power bus;
- an active rectifier connected to the power bus;
- a prime mover having a rotating member and being operable to generate mechanical energy from combustion of a fuel;
- an electric machine connected to the power bus via the active rectifier and having a rotor connected to the prime mover, the electric machine operable to convert mechanical energy from the prime mover into electrical energy supplied to the active rectifier and to receive electrical power from the active rectifier to produce mechanical energy;
- an engine control unit operable to control the prime mover;
- and
- a sensorless AC motor control system controlling the active rectifier and determining the angular position of the rotor and deriving the angular position of the rotating member therefrom and providing the determined position to the engine control unit to use to operate the prime mover;
- wherein, for each rotation of the rotating member the rotor of the electric machine completes at least two electrical rotations and wherein the engine control unit relates each rotation of the rotating member to one of the at least two electrical rotations;
- and
- wherein the electric machine rotates the prime mover through at least one complete operating cycle and the sensorless AC motor control system operates to detect a predefined angular position of the rotating member, the engine control unit responsive to the detected predefined rotational position to relate the detected predefined angular position to one of the at least two electrical rotations.
A method of operating an electrical generating system including a power bus, an electric machine having a rotor, an active rectifier connected between the power bus and the electric machine, a prime mover having a rotating member, the rotor of the electric machine connected to the rotating member, an engine control unit to control the prime mover and a sensorless AC motor control system to control the active rectifier, comprising the steps of:
- (i) the sensorless AC motor control system rotating the rotor of the electric machine and the rotating member and determining the angular position of the rotating member wherein the sensorless AC motor control system detects the occurrence of a preselected condition, the sensorless AC motor control system using the determined angular position to convert an electrical angular position of the rotor determined by the sensorless AC motor control system to a calculated angular position of the rotating member;
- (ii) providing the calculated angular position of the rotating member to the engine control unit;
- and
- (iii) the engine control unit employing the calculated angular position of the rotating member to operate the prime mover.
An electrical generating system comprising:
- a power bus;
- an active rectifier connected to the power bus;
- a prime mover having a rotating member and being operable to generate mechanical energy from combustion of a fuel;
- an electric machine connected to the power bus via the active rectifier and having a rotor connected to the prime mover, the electric machine operable to convert mechanical energy from the prime mover into electrical energy supplied to the active rectifier and to receive electrical power from the active rectifier to produce mechanical energy;
- an engine control unit operable to control the prime mover;
- a sensorless AC motor control system controlling the active rectifier and determining the angular position of the rotor and deriving the angular position of the rotating member therefrom and providing the determined position to the engine control unit to use to operate the prime mover;
- and
- an index position sensor operable to indicate the angular position of the rotating member relative to a predefined condition and wherein the sensorless AC motor control system relates the angular position of the rotating member to an electrical angular position of the rotor of the electric machine from the index position sensor;
- wherein, for each rotation of the rotating member the rotor of the electric machine completes at least two electrical rotations and wherein the engine control unit relates each rotation of the rotating member to one of the at least two electrical rotations.
Dependencies are inferred from the claim text.