VOLTAGE BALANCING SYSTEM AND METHOD FOR MULTILEVEL CONVERTERS
First Claim
1. A method of operating a flying capacitor multilevel converter including a direct current link and a plurality of phase legs each having a plurality of flying capacitors, the method comprising:
- employing redundant states to balance flying capacitor voltages by charging or discharging flying capacitors, wherein employing redundant states includeobtaining a load current of the flying capacitor multilevel converter;
utilizing a capacitor current of a phase terminal capacitor to determine redundant states when a load current value is lower than a threshold value; and
utilizing a load current direction to determine redundant states when the load current value is higher than the threshold value.
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Accused Products
Abstract
A method of operating a flying capacitor multilevel converter having a direct current link and a plurality of phase legs each having a plurality of flying capacitors includes employing redundant states to balance flying capacitor voltages by charging or discharging flying capacitors. The redundant states are employed by obtaining a load current of the flying capacitor multilevel converter. If a load current value is lower than a threshold value then a capacitor current of a phase terminal capacitor is utilized to determine redundant states else a load current direction is utilized to determine the redundant states.
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Citations
20 Claims
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1. A method of operating a flying capacitor multilevel converter including a direct current link and a plurality of phase legs each having a plurality of flying capacitors, the method comprising:
employing redundant states to balance flying capacitor voltages by charging or discharging flying capacitors, wherein employing redundant states include obtaining a load current of the flying capacitor multilevel converter; utilizing a capacitor current of a phase terminal capacitor to determine redundant states when a load current value is lower than a threshold value; and utilizing a load current direction to determine redundant states when the load current value is higher than the threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A multi-level converter system comprising:
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a converter including a direct current (DC) link and a plurality of phase legs each having a plurality of flying capacitors; and a converter controller configured to employ redundant states to balance flying capacitor voltages by charging or discharging the plurality of flying capacitors, wherein the controller employs redundant states by utilizing a capacitor current of a phase terminal capacitor to determine redundant states when a load current value is lower than a threshold value; and utilizing a load current direction to determine redundant states when the load current value is higher than the threshold value. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification