Generator with dual cycloconverter for 120/240 VAC operation

A generator system, comprising:

• an AC generator having an output coupled to a cycloconverter, the cycloconverter having a positive bank of naturally commutated switching devices and a negative bank of naturally commutated switching devices;
• a controller coupled to the naturally commutated switching devices of the positive and negative banks;
• a rotor position sensor for sensing the position of a rotor of the generator and generating a signal indicative of the position of the rotor, the rotor position sensor coupled to the controller;
• the controller using the rotor position signal to develop control waves which it uses to control switching of the naturally commutated switching devices of the positive and negative banks.

A generator system, comprising:

• an AC generator having an output coupled to a cycloconverter, the cycloconverter having a positive bank of naturally commutated switching devices and a negative bank of naturally commutated switching devices;
• a controller coupled to the naturally commutated switching devices of the positive and negative banks;
• the controller operating the positive and negative banks in a non-circulating mode, the controller enabling one of the positive and negative banks and disabling the other of the positive and negative banks based on the instantaneous output current of the cycloconverter;
• a bandpass filter for filtering the instantaneous output current of the cycloconverter to reduce current ripple and ensure that a signal output by the bandpass filter at a fundamental frequency does not have any phase shift relative to the instantaneous output current, the signal output by the band pass filter coupled to an input of a comparator that generates a signal indicative of whether the instantaneous output current has transitioned from positive to negative or from negative to positive.

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.

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.