Generator with dual cycloconverter for 120/240 VAC operation
First Claim
1. A dual mode generator system having a nominal output voltage of 120 VAC when it is in a first mode and nominal output voltages of both 120 VAC and 240 VAC when it is in a second mode, comprising:
- a permanent magnet generator having first and second sets of isolated three-phase windings and a rotor;
an engine for driving the rotor of the permanent magnet generator;
a plurality of rotor position sensors that generate signals indicative of the position of the rotor that are displaced one-hundred and twenty degrees from each other;
a first cycloconverter coupled to the first set of windings of the generator and a second cycloconverter coupled to the second set of windings of the generator;
the first and second cycloconverters each having a live output and a neutral output, the live output of the first cycloconverter coupled to a live output of a first outlet and the neutral output of the first cycloconverter coupled to a neutral output of the first outlet, the live output of the second cycloconverter coupled to a live output of a second outlet and the neutral output of the second cycloconverter coupled to a neutral output of the second outlet;
the first and second cycloconverters each having a positive bank of naturally commutated switching devices and a negative bank of naturally commutated switching devices;
a first filter capacitor coupled across the live output and neutral output of the first cycloconverter and a second filter capacitor coupled across the live output and neutral output of the second cycloconverter;
a third outlet coupled across the live outputs of the first and second outlets and a switch coupled across the live outputs of the first and second outlets;
a controller coupled to the naturally commutated switching devices and to the rotor position sensors;
the controller using the signals generated by the rotor position sensors to develop cosine control waves which it uses to control the switching of the naturally commutated switching devices of the first and second cycloconverters;
the controller operating the first and second cycloconverters so that output voltages at the live outputs of the first and second cycloconverters are in phase when the generator system is in a first mode with the switch closed paralleling the live outputs of the first and second cycloconverters where the nominal 120 VAC output voltage is produced at the first and second outlets with a greater available current than when the generator system is in the second mode;
the controller operating the first and second cycloconverters so that the output voltages at the live outputs of the first and second cycloconverters are one-hundred and eighty degrees out of phase with each other when the generator system is in a second mode with the switch open coupling the third outlet in series with the live outputs of the first and second cycloconverters with the nominal 120 VAC output voltage produced at the first and second outlets and the nominal 240 VAC output voltage produced at the third outlet.
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Abstract
A generator system has two modes of operation, such as 120 VAC and 240/120 VAC. The generator system has a permanent magnet generator with two independent sets of windings that each generate a three phase AC voltage. One three phase AC voltage is coupled to a first cycloconverter and the second three phase AC voltage is coupled to a second cycloconverter. Live outputs of each cycloconverter are coupled to each other through a switch, such as a relay, and netural outputs of each cycloconverter are coupled to ground. A controller controls the cycloconverters to provide the modes of operation. In the 120 VAC mode, the switch across the live outputs of the first and second cycloconverters is closed, shorting the live outputs of the first and second cycloconverters together so that the live outputs are in parallel and the controller operates the first and second cycloconverters so their output voltages are in phase with each other. When in the 240/120 VAC mode, the switch across the live outputs of the first and second cycloconverters is open so that the live outputs are in series and the controller operates the first and second cycloconverters so that their output voltages are 180 degrees out of phase. The permanent magnet generator has rotor position sensors that are used by a DC motor drive to drive the generator as a brushless DC motor to start the engine of the generator system and also to develop cosine wave information for use in controlling the cycloconverters.
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Citations
26 Claims
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1. A dual mode generator system having a nominal output voltage of 120 VAC when it is in a first mode and nominal output voltages of both 120 VAC and 240 VAC when it is in a second mode, comprising:
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a permanent magnet generator having first and second sets of isolated three-phase windings and a rotor; an engine for driving the rotor of the permanent magnet generator; a plurality of rotor position sensors that generate signals indicative of the position of the rotor that are displaced one-hundred and twenty degrees from each other; a first cycloconverter coupled to the first set of windings of the generator and a second cycloconverter coupled to the second set of windings of the generator; the first and second cycloconverters each having a live output and a neutral output, the live output of the first cycloconverter coupled to a live output of a first outlet and the neutral output of the first cycloconverter coupled to a neutral output of the first outlet, the live output of the second cycloconverter coupled to a live output of a second outlet and the neutral output of the second cycloconverter coupled to a neutral output of the second outlet; the first and second cycloconverters each having a positive bank of naturally commutated switching devices and a negative bank of naturally commutated switching devices; a first filter capacitor coupled across the live output and neutral output of the first cycloconverter and a second filter capacitor coupled across the live output and neutral output of the second cycloconverter; a third outlet coupled across the live outputs of the first and second outlets and a switch coupled across the live outputs of the first and second outlets; a controller coupled to the naturally commutated switching devices and to the rotor position sensors; the controller using the signals generated by the rotor position sensors to develop cosine control waves which it uses to control the switching of the naturally commutated switching devices of the first and second cycloconverters; the controller operating the first and second cycloconverters so that output voltages at the live outputs of the first and second cycloconverters are in phase when the generator system is in a first mode with the switch closed paralleling the live outputs of the first and second cycloconverters where the nominal 120 VAC output voltage is produced at the first and second outlets with a greater available current than when the generator system is in the second mode; the controller operating the first and second cycloconverters so that the output voltages at the live outputs of the first and second cycloconverters are one-hundred and eighty degrees out of phase with each other when the generator system is in a second mode with the switch open coupling the third outlet in series with the live outputs of the first and second cycloconverters with the nominal 120 VAC output voltage produced at the first and second outlets and the nominal 240 VAC output voltage produced at the third outlet. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. In a dual mode generator system having a nominal output voltage of 120 VAC when it is in a first mode and nominal output voltages of both 120 VAC and 240 VAC when it is in a second mode, the generator system having a permanent magnet generator having first and second sets of isolated three-phase windings and a rotor, an engine for driving the rotor of the permanent magnet generator, a plurality of rotor position sensors that generate signals indicative of the position of the rotor that are displaced one-hundred and twenty degrees from each other, a first cycloconverter coupled to the first set of windings and a second cycloconverter coupled to the second set of windings, each cycloconverter having a live output and a neutral output, the live output of the first cycloconverter coupled to a live output of a first outlet and the neutral output of the first cycloconverter coupled to a neutral output of the first outlet, the live output of the second cycloconverter coupled to a live output of a second outlet and the neutral output of the second cycloconverter coupled to a neutral output of the second outlet, the first and second cycloconverters each having a positive bank of naturally commutated switching devices and a negative bank of naturally commutated switching devices, a first filter capacitor coupled across the live output and neutral output of the first cycloconverter and a second filter capacitor coupled across the live output and neutral output of the second cycloconverter, a third outlet coupled across the live outputs of the first and second outlets and a switch coupled across the live outputs of the first and second outlets in parallel with the third outlet, a method of operating the dual mode generator system, comprising
using the signals indicative of the position of the rotor of the permanent magnet generate to develop cosine control waves to control the switching of the naturally commutated switching devices of the first and second cycloconverters, operating the generator system in the first mode with the switch closed coupling the live outputs of the first and second cycloconverters in parallel and operating the first and second cycloconverters so that output voltages at their live outputs are in phase where the nominal 120 VAC output voltage is produced at the first and second outlets with a greater available current than available when the generator system is in the second mode; - and
operating the generator system in the second mode with the switch open coupling the live outputs of the first and second cycloconverters in series and operating the first and second cycloconverters so that the output voltages at their live outputs are one-hundred and eighty degrees out of phase where the nominal 120 VAC output voltage is produced at the first and second outlets and the 240 VAC output voltage is produced at the third outlet. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification