Power generating system
AssigneeSundstrand Corporation
InventorsAlexander Cook, Richard W. Reynolds
Life of this patent
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Abstract
A power supply system for developing electrical power from variable-speed motive power produced by a prime mover includes a differential speed summer having a first shaft coupled to the prime mover and further having second and third shafts coupled to first and second generators, respectively, a power conditioner coupled to the second generator for conditioning the power developed thereby and means for regulating the conditioned power developed by the second generator so that the first generator develops constant-frequency AC power.
Claims64
A power supply system for developing electrical power at a system output from variable-speed motive power produced by a prime mover, comprising:
- a differential speed summer having a first shaft coupled to the prime mover and further having second and third shafts;
- a first generator coupled to the second shaft of the differential;
- a second generator coupled to the third shaft of the differential;
- a power conditioner for conditioning the total output power of the second generator;
- and
- means for regulating a parameter of the conditioned total output power of the second generator to cause the motive power shaft of the first generator to rotate at a constant speed so that such generator develops constant-frequency AC output power at the system output;
- wherein the power conditioner comprises an inverter and the regulating means includes means for controlling the inverter so that it produces output power at a desired output frequency and wherein the inverter is coupled to the first generator output so that the first generator develops output power at a frequency equal to the inverter output frequency.
A power supply system for developing AC and DC output power from variable-speed motive power produced by a prime mover, comprising:
- first and second wound-field generators each having a motive power shaft, an exciter which receives field excitation and electrical power windings;
- a differential having first through third motive power shafts coupled to the prime mover and to the motive power shafts of the first and second generators, respectively;
- a control for controlling the field excitation of the second generator to in turn operate the first generator at a constant speed and the second generator at a variable speed so that the first generator develops constant-frequency AC output power at an output thereof and the second generator develops variable-frequency AC power;
- and
- a rectifier circuit for rectifying the variable-frequency output of the second generator to develop the DC output power.
A power supply system for developing constant-frequency AC output power and DC output power from variable-speed motive power produced by a prime mover, comprising:
- a differential speed summer having a first shaft coupled to the prime mover and second and third shafts;
- a first generator coupled to the second shaft of the differential having first and second sets of windings which develop first and second power outputs, respectively;
- a second generator coupled to the third shaft of the differential which develops output power at an output thereof;
- a first rectifier coupled between the output of the second generator and a DC bus for rectifying the output power developed thereby;
- a control circuit for regulating the rectified second generator output whereby the first generator is driven at a constant speed by the second differential shaft so that constant-frequency AC power is developed at the first and second power outputs of the first generator;
- a second rectifier coupled between the second set of windings of the first generator and the DC bus for rectifying the constant-frequency power developed thereby wherein the outputs of the first and second rectifiers are combined to produce the DC output power on the DC bus;
- and
- a DC/AC converter coupled between the DC bus and the first set of windings of the first generator for deriving constant-frequency AC power from the combined outputs of the rectifiers on the DC bus whereby such AC power is combined with the first power output of the first generator to produce the constant-frequency AC output power.
A power supply system for developing constant-frequency AC output power at a system output from variable-speed motive power produced by a prism mover, comprising:
- first and second wound-field generators each having a motive power shaft, an exciter which receives field excitation and electrical power windings;
- a differential having first through third motive power shafts coupled to the prime mover and to the motive power shafts of the first and second generators, respectively;
- a power converter coupled to the second generator including an inverter for developing constant-frequency power at an inverter output from the total power output of the second generator;
- means for coupling the inverter output to the power windings of the first generator wherein the inverter output and the power windings of the first generator form the system output;
- and
- a control for controlling the field excitation of the first and second generators such that the first generator develops AC power at a constant frequency equal to the frequency of the power developed by the inverter.
A method of bringing a power supply system up to a condition of regulated output frequency once a prime mover which provides motive power to the system is within a speed operating range wherein the power supply includes a differential having first through third shafts coupled to the prime mover and to motive power shafts of first and second generators, respectively, and a power converter coupled between electrical power outputs of the first and second generators whereby the outputs of the first generator and the power converter are combined to develop AC output power at a system output, comprising the steps of:
- (a) applying a source of input power to the power converter;
- (b) operating the power converter to provide power to the first generator to operate it as a motor to thereby force the motive power shaft thereof to rotate at a particular speed;
- and
- (c) thereafter controlling the frequency of the power converter output to maintain the speed of the first generator motive power shaft constant so that the first generator and power converter together develop constant-frequency AC power.
A method of bringing a prime mover up to self-sustaining speed wherein the prime mover is coupled to a power supply of the type including a differential speed summer having a first shaft coupled to the prime mover, a second shaft coupled to a motive power shaft of a first generator and a third shaft coupled to a motive power shaft of a second generator having an output coupled to a power converter, the power converter including an output coupled to an output of the first generator, comprising the steps of:
- (a) applying a source of power to the power converter;
- (b) operating the power converter so that it develops AC power which is applied to the first generator to accelerate the motive power shaft of same;
- (c) applying an AC power source to the first generator when the motive power shaft reaches a particular speed to operate same as a motor so that the motive power shaft of the second generator rotates and thereby causes the second generator to develop output power;
- and
- (d) placing an electrical load on the second generator so that starting torque is developed which is transferred by the differential to the prime mover to bring same up to self-sustaining speed.
A method of operating a power supply system including a differential having first through third shafts coupled to a prime mover and to motive power shafts of first and second generators, respectively, and a power converter coupled to the second generator for conditioning the output power of the second generator, comprising:
- operating the first and second generators when the prime mover speed is within an operating range so that the first generator and the power conditioner develop constant-frequency power at a system output;
- and
- preventing rotation of the motive power shaft of the first generator and controlling the power converter so that it develops constant-frequency AC power when the prime mover speed is below the operating range.
A method of operating a power supply system including a differential having first through third shafts coupled to a prime mover and to motive power shafts of first and second generators, respectively, and a power converter coupled to the second generator for conditioning the output power of the second generator, comprising:
- operating the first and second generators when the prime mover speed is within an operating range so that the first generator and the power conditioner develop constant-frequency power at a system output;
- and
- applying a source of power to the second generator to operate same as a motor so that the motive power shaft of the first generator is rotated at a constant speed whereby the first generator continues to develop constant-frequency AC power when the prime mover speed drops below the operating range.
A power supply system for developing constant-frequency AC output power from variable-speed motive power produced by a prime mover, comprising:
- first and second generators each having a motive power shaft wherein the second generator is of the permanent magnet type;
- a differential having first through third motive power shafts coupled to the prime mover and to the motive power shafts of the first and second generators, respectively;
- a rectifier and DC/DC converter coupled to the output of the second generator for converting the power output of the second generator into DC power;
- an inverter coupled to the DC/DC converter for developing constant-frequency AC power at an inverter output from the DC power wherein the inverter output is coupled to the electrical power windings of the first generator;
- and
- a control coupled to the first generator including a phase comparator for developing a control signal representing the phase difference between the output current of the inverter and the first generator wherein the control signal controls the power output of the first generator;
- whereby the first generator and the inverter develop the constant-frequency AC output power.
Dependencies are inferred from the claim text.