Neutral point regulator hardware for a multi-level drive
AssigneeOtis Elevator Company
InventorsIsmail Agirman, HanJong Kim
Life of this patent
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Abstract
The present disclosure relates generally to a neutral point balancing scheme for power converter systems. The balancing circuit includes a first side of a first electrical component operably coupled to a mid-point of the DC link capacitor bank, and a switching combination operably coupled to the second side of the first electrical component, a positive voltage, and a negative voltage rail, wherein the switching combination is configured to generate a pulse-width modulation signal at the second side of the first electrical component.
Claims17
A balancing circuit for a multi-level converter including a DC link capacitor bank, the balancing circuit comprising:
- a first electrical component, wherein a first side of the first component is operably coupled to a mid-point of the DC link capacitor bank, the mid-point including a floating potential between a positive voltage rail and a negative voltage rail;
- and
- a switching combination operably coupled to the second side of the first electrical component, the positive voltage, and the negative voltage rail, wherein the switching combination is configured to generate a pulse-width modulation signal at the second side of the first electrical component.
A power generation system comprising:
- a multi-level converter, wherein the multi-level converter comprises a DC link capacitor bank;
- and
- a balancing circuit operably coupled to the multi-level converter, wherein the balancing circuit comprises:
- a first electrical component, wherein a first side of the first component is operably coupled to a mid-point of the DC link capacitor bank, the mid-point including a floating potential between a positive voltage rail and a negative voltage rail;
- and
- a switching combination operably coupled to the second side of the first electrical component, the positive voltage, and the negative voltage rail, wherein the switching combination is configured to generate a pulse-width modulation signal at the second side of the first electrical component.
A method for providing voltage balance control for a multi-level converter including a DC link capacitor bank comprising at least one mid-point at a floating potential between a positive voltage rail and a negative voltage rail, and a balancing circuit operably coupled to the mid-point of the multi-level converter, wherein the balancing circuit comprises a plurality of switches operably coupled to a first electrical component, the method comprising the steps:
- determining a voltage difference signal, wherein the voltage difference signal comprises the difference between a first voltage and a second voltage to create a voltage difference signal, wherein the first voltage comprises the voltage between the positive voltage rail and the at least one mid-point and the second voltage comprises the voltage between the negative voltage rail and the at least one mid-point;
- determining a current reference value by passing the voltage difference signal through a first regulator;
- determining a neutral point error signal by determining the difference between the current reference value and a measured current value;
- and
- actuating at least one of the switches based at least in part on the neutral point error signal.
Dependencies are inferred from the claim text.