US 4,481,459 AGranted

Combined starting/generating system and method

AssigneeSundstrand Corporation

InventorsByron R. Mehl, Raymond N. Olson, Timothy F. Glennon

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Abstract

A power conversion system for converting between electric and motive power may be utilized either in a generating mode to generate electric power from motive power supplied by a prime mover or in a starting mode wherein motive power is developed by the power conversion system from electrical power and is supplied through a torque converter to the prime mover to start same. The power conversion system includes a main generator, an exciter and a permanent magnet generator, or PMG, which together comprise a brushless alternator. When operated in the starting mode, power is supplied to the PMG to cause it to act as a motor and thereby drive a rotor which is common to the PMG, exciter and main generator. Once a predetermined operating condition of the generator is attained, the main generator is supplied power from a motor control to cause the generator to act as a synchronous motor and the power supply to the PMG is disconnected. The torque converter is then commanded to transfer motive power from the generator to the prime mover to start same.

Claims14

Dependent claims

In a power conversion system operable in either a starting mode wherein the conversion system converts electrical power into motive power to start a prime mover or in a generating mode wherein the conversion system develops electrical power from motive power supplied by the prime mover including a main dynamoelectric machine, means actuable to supply field current to the main machine including a permanent magnet generator, or PMG, the main machine and PMG having a common rotor, and a torque converter operable to transfer power between the prime mover and the common rotor, a control for operating the conversion system in the starting mode, comprising:

a source of electrical power;
means for coupling the source of electrical power to the PMG when the conversion system is operated in the starting mode to cause the PMG to operate as a motor and drive the common rotor;
means coupled to the main machine for applying electrical power thereto to cause the main machine to operate as a synchronous motor when a predetermined operating condition of the main machine is attained;
means for disconnecting the source of electrical power from the PMG after the predetermined operating condition is attained;
and
means coupled to the torque converter and responsive to an operating parameter of the main machine for controlling the torque converter including means for disabling the torque converter to decouple the main machine from the prime mover until the predetermined operating condition is attained and means for enabling the torque converter to couple the main machine to the prime mover to start the latter when the main machine is operated as the synchronous motor.

3 more elements

In a power conversion system selectively operable in either a starting mode wherein the conversion system converts electrical power into motive power to start a prime mover or in a generating mode wherein the conversion system develops electrical power from motive power supplied by the prime mover including a synchronous main dynamoelectric machine, means for providing field current to the main machine including a permanent magnet generator, or PMG, the main machine and PMG having a common rotor and a torque converter selectively actuable to transfer motive power between the prime mover and the common rotor, a control system for operating the conversion system, comprising:

means for selecting either the generating or starting modes of operation;
a source of electrical power;
and
a control unit coupled to the selecting means and to the torque converter for operating the system in the selected mode, the control unit further including means for coupling the source of electrical power to the PMG to operate it as a motor to drive the common rotor when the starting mode is selected, means for deactuating the torque converter to allow the common rotor to rotate at increasing speeds in an unloaded condition, means for sensing the speed of the common rotor, means for applying electrical power to the main machine to operate it as a synchronous motor when the common rotor reaches a first predetermined level, means for disconnecting the source of electrical power from the PMG after the first predetermined level is reached and means for actuating the torque converter to cause motive power to be transferred from the main machine to the prime mover to start same when the main machine is operated as a synchronous motor.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 06/563,449Filed 20 Dec 1983
Granted: 6 Nov 1984
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

F02N 11/0859
Circuits specially adapted for starting of engines: specially adapted to the type of the starter motor or integrated into it
F02N 11/04
Starting of engines by means of electric motors: the motors being associated with current generators
F02N 2011/0888
Components of the circuit not provided for by previous groups: dC/DC converters
F02N 2011/0896
Components of the circuit not provided for by previous groups: inverters for electric machines, e.g. starter-generators