US5581168A — Starter/generator system with DC link current con…

Claim 1

Independent Claim 230 words

A control for a synchronous generator having a main generator portion with an armature winding and a field winding rotatable with respect to said armature winding, said synchronous generator being attached directly to a prime mover and usable in a starting mode of operation whereby the main generator portion field winding is accelerated with respect to the main generator portion armature winding to directly accelerate the prime mover, said control comprising: an inverter coupled to the main generator portion armature winding to supply power to said main generator portion armature winding during the starting mode of operation; a DC link connected to said inverter, said DC link providing a DC link current to said inverter during the starting mode of operation; a source of DC power coupled to said DC link, said source of DC power providing an output voltage to said DC link; a controller coupled to said DC link for controlling to an optimum level the magnitude of the DC link current provided to said inverter by said DC link during the starting mode of operation whereby said main generator portion armature winding is accelerated with respect to said main generator portion field winding thereby directly accelerating the prime mover; and wherein said optimum level is determined as that current level which results in a fixed percentage drop in said output voltage of said source of DC power.

Claim 2

Dependent Claim 230 words

A control for a synchronous generator having a main generator portion with an armature winding and a field winding rotatable with respect to said armature winding, said synchronous generator being attached directly to a prime mover and usable in a starting mode of operation whereby the main generator portion field winding is accelerated with respect to the main generator portion armature winding to directly accelerate the prime mover, said control comprising: an inverter coupled to the main generator portion armature winding to supply power to said main generator portion armature winding during the starting mode of operation; a DC link connected to said inverter, said DC link providing a DC link current to said inverter during the starting mode of operation; a source of DC power coupled to said DC link, said source of DC power providing an output voltage to said DC link; a controller coupled to said DC link for controlling to an optimum level the magnitude of the DC link current provided to said inverter by said DC link during the starting mode of operation whereby said main generator portion armature winding is accelerated with respect to said main generator portion field winding thereby directly accelerating the prime mover; and wherein said optimum level is determined as that current level which results in a fixed percentage drop in said output voltage of said source of DC power.

Claim 3

Dependent Claim 66 words

A control as defined in claim 1 additionally comprising: a current sensor that generates a sensed current signal relating to the magnitude of said DC link current; a comparator that compares said sensed current signal with a current reference signal; and means for providing a variable controlled voltage across said DC link based upon the magnitudes of said sensed current signal and said current reference signal.

Claim 4

Dependent Claim 16 words

A control as defined in claim 2 wherein said voltage providing means comprises a DC/DC converter.

Claim 5

Dependent Claim 15 words

A control as defined in claim 1 wherein said current sensor comprises a current transformer.

Claim 6

Dependent Claim 51 words

A control as defined in claim 1 wherein said controller comprises: a comparator that compares said DC link current with a current reference; and a DC/DC converter coupled to said comparator that provides a voltage to said inverter based upon the magnitudes of said DC link current and said current reference.

Claim 7

Dependent Claim 66 words

A control as defined in claim 1 wherein said source of DC power coupled to said DC link is a source of battery power and wherein the optimum magnitude of said DC link current is controlled to a value which results in a drop in the output voltage of said source of battery power to one-half of the rated voltage of said source of battery power.

Claim 8

Dependent Claim 57 words

A control as defined in claim 1 additionally comprising means for generating a speed signal relating to the speed of rotation of said main generator portion armature winding relative to said main generator field winding and wherein said DC link current is controlled based upon the relative magnitudes of said speed signal and a speed reference signal.

Claim 9

Dependent Claim 274 words

A synchronous generator directly coupled to a prime mover usable in both a starting mode of operation and a generating mode of operation, said synchronous generator comprising: a permanent magnet generator having a permanent magnet and an armature winding rotatable with respect to said permanent magnet; an exciter portion having an exciter armature winding and an exciter field winding rotatable with respect to said exciter armature winding; a main generator portion having a main generator armature winding and a main generator field winding rotatable with respect to said main generator armature winding; means for providing power to said main generator portion armature winding during said starting mode of operation, said means for providing power comprising: an inverter coupled to the main generator portion armature winding to supply power to said main generator portion armature winding during the starting mode of operation; a DC link connected to said inverter, said DC link providing a DC link current to said inverter during the starting mode of operation; a source of DC power coupled to said DC link, said source of DC power providing an output voltage to said DC link; control means coupled to said DC link for controlling to an optimum level the magnitude of the DC link current provided to said inverter by said DC link during the starting mode of operation whereby said main generator portion armature winding is accelerated with respect to said main generator portion field winding thereby directly accelerating the prime mover; and wherein said optimum level is determined as that current level which results in a fixed percentage drop in said output voltage of said source of DC power.

Claim 10

Dependent Claim 274 words

A synchronous generator directly coupled to a prime mover usable in both a starting mode of operation and a generating mode of operation, said synchronous generator comprising: a permanent magnet generator having a permanent magnet and an armature winding rotatable with respect to said permanent magnet; an exciter portion having an exciter armature winding and an exciter field winding rotatable with respect to said exciter armature winding; a main generator portion having a main generator armature winding and a main generator field winding rotatable with respect to said main generator armature winding; means for providing power to said main generator portion armature winding during said starting mode of operation, said means for providing power comprising: an inverter coupled to the main generator portion armature winding to supply power to said main generator portion armature winding during the starting mode of operation; a DC link connected to said inverter, said DC link providing a DC link current to said inverter during the starting mode of operation; a source of DC power coupled to said DC link, said source of DC power providing an output voltage to said DC link; control means coupled to said DC link for controlling to an optimum level the magnitude of the DC link current provided to said inverter by said DC link during the starting mode of operation whereby said main generator portion armature winding is accelerated with respect to said main generator portion field winding thereby directly accelerating the prime mover; and wherein said optimum level is determined as that current level which results in a fixed percentage drop in said output voltage of said source of DC power.

Claim 11

Dependent Claim 60 words

A synchronous generator as defined in claim 8 wherein said control means comprises: a comparator that compares said DC link current with a current reference; and a DC/DC converter coupled to said comparator that provides to said inverter a controlled voltage having a magnitude which is based upon the relative magnitudes of said DC link current and said current reference.

Claim 12

Dependent Claim 47 words

A synchronous generator as defined in claim 9 wherein said source of DC power coupled to said DC link is a source of battery power, and wherein said current reference has a magnitude generally equal to one-half of the rated voltage of said source of battery power.

Claim 13

Dependent Claim 57 words

A synchronous generator as defined in claim 9 additionally comprising means for generating a speed signal relating to the speed of rotation of said main generator portion armature winding relative to said main generator field winding and wherein said current reference has a magnitude based on the difference between said speed signal and a speed reference signal.

Claim 14

Dependent Claim 123 words

A synchronous generator as defined in claim 8 additionally comprising: a rectifier; a filter; and switching means coupled to said rectifier and said filter, said switching means having a first position during said starting mode of operation in which said main generator portion armature winding is supplied power from said inverter to accelerate said main generator armature winding with respect to said main generator portion field winding to directly accelerate the prime mover and a second position during said generating mode wherein said main generator portion armature winding is connected to said rectifier whereby said main generator portion armature winding provides AC power to said rectifier, said rectifier provides DC power to said inverter, and said inverter provides AC power to said filter.

Claim 15

Dependent Claim 240 words

A control for a synchronous generator having a main generator portion with an armature winding and a field winding rotatable with respect to said armature winding, said synchronous generator being directly coupled to a prime mover and usable in a starting mode of operation whereby the main generator portion field winding is accelerated with respect to the main generator portion armature winding by power provided by either a battery or a DC source thereby directly accelerating the prime mover, said control comprising: a first power source comprising a battery; a second power source comprising a DC power source; an inverter coupled to the main generator portion armature winding; a DC link connected to said inverter, said DC link providing a DC link current to said inverter during the starting mode of operation; a controller coupled to said DC link for controlling to an optimum level the magnitude of the DC link current provided to said inverter by said DC link during the starting mode of operation whereby said main generator portion armature winding is accelerated with respect to said main generator portion field winding thereby directly accelerating the prime mover; and switching means coupled to said first source of power and said second source of power, said switching means causing either said first source of power or said second source of power to be connected to supply power for generating said DC link current during the starting mode of operation.

Claim 16

Dependent Claim 240 words

A control for a synchronous generator having a main generator portion with an armature winding and a field winding rotatable with respect to said armature winding, said synchronous generator being directly coupled to a prime mover and usable in a starting mode of operation whereby the main generator portion field winding is accelerated with respect to the main generator portion armature winding by power provided by either a battery or a DC source thereby directly accelerating the prime mover, said control comprising: a first power source comprising a battery; a second power source comprising a DC power source; an inverter coupled to the main generator portion armature winding; a DC link connected to said inverter, said DC link providing a DC link current to said inverter during the starting mode of operation; a controller coupled to said DC link for controlling to an optimum level the magnitude of the DC link current provided to said inverter by said DC link during the starting mode of operation whereby said main generator portion armature winding is accelerated with respect to said main generator portion field winding thereby directly accelerating the prime mover; and switching means coupled to said first source of power and said second source of power, said switching means causing either said first source of power or said second source of power to be connected to supply power for generating said DC link current during the starting mode of operation.

Claim 17

Independent Claim 190 words

A method of starting a prime mover directly coupled to a synchronous generator having a main generator portion with an armature winding and a field winding rotatable with respect to said armature winding by providing power to a DC link from a source of DC power, and via the DC link to an inverter coupled to the main generator portion armature winding, said method comprising the steps of: (a) providing a DC link current to the inverter via the DC link; (b) generating a sensed current signal relating to the magnitude of the DC link current provided to the inverter; (c) generating a current reference signal representing the desired magnitude of the DC link current to be provided to the inverter via the DC link, the desired magnitude of the DC link current being relative to a predetermined percentage of rated voltage of the source of DC power supplying the DC link; (d) providing a variable controlled voltage across the DC link having a magnitude based upon the relative magnitudes of said sensed current signal generated during said step (b) and said current reference signal generated during said step (c).

Claim 18

Independent Claim 190 words

A method of starting a prime mover directly coupled to a synchronous generator having a main generator portion with an armature winding and a field winding rotatable with respect to said armature winding by providing power to a DC link from a source of DC power, and via the DC link to an inverter coupled to the main generator portion armature winding, said method comprising the steps of: (a) providing a DC link current to the inverter via the DC link; (b) generating a sensed current signal relating to the magnitude of the DC link current provided to the inverter; (c) generating a current reference signal representing the desired magnitude of the DC link current to be provided to the inverter via the DC link, the desired magnitude of the DC link current being relative to a predetermined percentage of rated voltage of the source of DC power supplying the DC link; (d) providing a variable controlled voltage across the DC link having a magnitude based upon the relative magnitudes of said sensed current signal generated during said step (b) and said current reference signal generated during said step (c).

Claim 19

Dependent Claim 20 words

A method as defined in claim 14 wherein said sensed current signal is generated by a DC link current sensor.

Claim 20

Dependent Claim 44 words

A method as defined in claim 14 wherein the source providing power to said DC link is a source of battery power and wherein said current reference signal has a magnitude relating to one-half of the rated voltage of a source of battery power.

Claim 21

Dependent Claim 68 words

A method as defined in claim 14 additionally comprising the step of (e) generating a sensed speed signal relating to the relative rotational speed of the main generator portion armature winding and the main generator portion field winding and wherein said current reference signal has a magnitude relating to the desired relative rotational speed of the main generator portion armature winding and the main generator portion field winding.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1999-12-03	2000-06-03	2000-12-03	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2003-12-03	2004-06-03	2004-12-03	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2007-12-03	2008-06-03	2008-12-03	$7700.00	Window Closed / Lapsed

Starter/generator system with DC link current control

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