MULTILEVEL CONVERTER AND METHOD OF STARTING UP A MULTILEVEL CONVERTER
First Claim
1. A multilevel converter for converting between an AC voltage and a DC voltage, the multilevel converter (10) having an AC terminal (15) and a DC terminal (11, 12) for connecting the multilevel converter to either an AC power source (14) or a DC power source (13), respectively, which supplies the voltage to be converted, wherein the multilevel converter (10) comprises:
- at least one converter leg (21), the DC terminal comprising a first DC terminal (11) and a second DC terminal (12), the converter leg (21) comprising plural converter cells (30, 31, 32) connected in series between the first and second DC terminals (11, 12), wherein the AC terminal (15) of the multilevel converter is electrically coupled to an electrical link (41) between two of said converter cells (30, 31, 32) of said converter leg (21), anda resistor circuit (71, 72) comprised in said converter leg (21) and connected in series with said converter cells (30, 31, 32), the resistor circuit (71, 72) being configured so as to be capable of connecting a resistance (RC1, RC2) in series with the converter cells (30, 31, 32) of the converter leg (21),wherein each converter cell (30, 31, 32) comprises a capacitor (55), the multilevel converter (10) being configured so as to enable a charging of the capacitor (55) of a converter cell (30, 31, 32) from the power source connected to the AC terminal (15) or the DC terminal (11, 12) of the multilevel converter through the resistance of the resistor circuit (71, 72).
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0 Petitions
Accused Products
Abstract
A multilevel converter for converting between an AC voltage and a DC voltage and a method of starting up such multilevel converter are provided. The multilevel converter has an AC terminal and a DC terminal for connecting the multilevel converter to either an AC power source or a DC power source, respectively, which supplies the voltage to be converted. The multilevel converter further comprises at least one converter leg, the DC terminal comprising a first and a second DC terminal, the converter leg comprising plural converter cells connected in series between the first and second DC terminals. The AC terminal of the multilevel converter is electrically coupled to an electrical link between two of said converter cells of said converter leg.
45 Citations
15 Claims
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1. A multilevel converter for converting between an AC voltage and a DC voltage, the multilevel converter (10) having an AC terminal (15) and a DC terminal (11, 12) for connecting the multilevel converter to either an AC power source (14) or a DC power source (13), respectively, which supplies the voltage to be converted, wherein the multilevel converter (10) comprises:
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at least one converter leg (21), the DC terminal comprising a first DC terminal (11) and a second DC terminal (12), the converter leg (21) comprising plural converter cells (30, 31, 32) connected in series between the first and second DC terminals (11, 12), wherein the AC terminal (15) of the multilevel converter is electrically coupled to an electrical link (41) between two of said converter cells (30, 31, 32) of said converter leg (21), and a resistor circuit (71, 72) comprised in said converter leg (21) and connected in series with said converter cells (30, 31, 32), the resistor circuit (71, 72) being configured so as to be capable of connecting a resistance (RC1, RC2) in series with the converter cells (30, 31, 32) of the converter leg (21), wherein each converter cell (30, 31, 32) comprises a capacitor (55), the multilevel converter (10) being configured so as to enable a charging of the capacitor (55) of a converter cell (30, 31, 32) from the power source connected to the AC terminal (15) or the DC terminal (11, 12) of the multilevel converter through the resistance of the resistor circuit (71, 72). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of starting up a multilevel converter, the multilevel converter (10) being adapted to convert between an AC voltage and a DC voltage, the multilevel converter having an AC terminal (15) and a DC terminal (11, 12) for connecting the multilevel converter to either an AC power source (14) or a DC power source (13), respectively, which supplies the voltage to be converted, the multilevel converter comprising a converter leg (21) with plural converter cells (30, 31, 32) connected in series, each converter cell comprising a capacitor (55), the method comprising the steps of
supplying electric power of the AC power source or the DC power source to the converter leg (21), connecting a resistance (RC1, RC2) in series with the converter cells (30, 31, 32), and connecting the capacitor (55) of one or more converter cells (30, 31) in series with the resistance (RC1, RC2), wherein the one or more capacitors (55) connected in series with the resistance are charged from the connected power source (13, 14) through the resistance (RC1, RC2).
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15. A method of discharging a capacitor (55) of a multilevel converter (10), the multilevel converter being adapted to convert between an AC voltage and a DC voltage, the multilevel converter comprising at least a first and a second converter leg (21, 22) each being connected between a first DC terminal (11) and a second DC terminal (12) of the multilevel converter (10), wherein each the converter legs (21, 22) comprises plural converter cells (30, 31, 32) connected in series between the first and second DC terminals (11, 12), each converter cell comprising a capacitor (55), the method comprising the steps of
disconnecting the power source and a load from the multilevel converter (10), connecting the capacitor (55) of a converter cell (30, 31, 32) comprised in one of the converter legs (21, 22) in series with the converter cells of the converter leg, connecting a resistance (RC1, RC2) in series with the capacitor (55) of the converter cell (30, 31, 32), and providing an electrical connection (80) between the first and second converter legs (21, 22) such that the capacitor (55) is discharged through the resistance (RC1, RC2), at least a part of the first and second converter legs (21, 22), and said electrical connection (80).
Specification