US 6,621,719 B2 · Converter with additional voltage addition or subtraction at the output

Abstract

A circuit for transmitting real power from a DC voltage side to AC voltage-side connections has a first power converter (4) with load connections (5) connected in series with second power converters (7) having a lower intermediate-circuit capacitor voltage. This allows finer voltage graduation of a sum voltage at the AC voltage-side connections (10). Voltages of intermediate-circuit capacitances of power converters (4, 7) and a common-mode voltage of the AC voltage-side connections can be jointly regulated. The intermediate-circuit capacitor voltages can be kept essentially constant. The second power converters (7) can interchange real power with a load (11) and the first power converter (4). Changes in the intermediate-circuit capacitor voltages can be calculated in advance using a model of the converter. The common-mode voltage can be selected to minimize a weighted sum of the squares of the errors between the intermediate-circuit capacitor voltages and the respective nominal values.

Claims11

Dependent claims

A power-electronic circuit arrangement for transmitting real power from a DC voltage-side to at least two AC voltage-side connections or vice versa, comprising

a first power converter which is connected to a DC voltage source with a first intermediate-circuit capacitor voltage and has at least two load connections,
and at least one second power converter, which is connected to one of the load connections and is connected to an AC voltage-side connection, and which has a second intermediate-circuit capacitor voltage and in which case, by means of the second power converter, one or more of:
the positive second intermediate-circuit capacitor voltage, the negative second intermediate-circuit capacitor voltage or zero volts can be added to a voltage value which can be connected by the first power converter to its load connection,
wherein the at least one second power converter does not have its own power supply means.

1 more element

A method for transmitting real power by means of power-electronic circuit arrangement from a DC voltage side to at least two AC voltage-side connections of the circuit arrangement, or vice versa, with

a) an associated voltage value being connected to each of at least two load connections of the first power converter by means of said first power converter, which is connected to a DC voltage source with a first intermediate-circuit capacitor voltage,
b) one or more of:
the positive second intermediate-circuit capacitor voltage, the negative second intermediate-circuit capacitor voltage or zero volts being added to the voltage value of the load connection by means of at least one second power converter, which is connected to one of the load connections and is connected to an AC-voltage side connection and has a second intermediate-circuit capacitor voltage, wherein
c) at least one intermediate-circuit capacitor voltage of the at least one second power converter and one common-mode voltage of the AC voltage-side connections of the circuit arrangement are regulated by means of joint regulation, and
d) semiconductor switches for the first power converter and for the at least one second power converter are driven on the basis of output variables from this regulating device.

2 more elements

Dependencies are inferred from the claim text.

Converter with additional voltage addition or subtraction at the output

Life of this patent

Converter with additional voltage addition or subtraction at the output

Life of this patent

Abstract

Claims11