Multilevel valve for voltage sourced converter transmission
OwnerDennis A. Woodfordinventor
Life of this patent
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Abstract
A method for transforming electric power from high voltage AC voltage and AC current to high voltage DC voltage and DC current and from high voltage DC voltage and DC current to high voltage AC voltage and AC current. The method includes passing the power through voltage sourced converters whose legs are comprised all or in part with 3 step ladder bridge modules connected in series.
Claims25
A method for transmitting electric power over a high voltage power grid between
- high voltage AC and DC network elements, comprising:
- implementing a voltage sourced converter comprising a plurality of series-connected modules in each leg of the voltage sourced converter, the voltage sourced converter converts high voltage DC to AC by operating the series-connected modules with each module being configured to convert a DC voltage to a three step DC voltage ladder;
- selectively controlling a switching operation of six subportions in each module by which the module is placed in one of three available operational states;
- in response to the switching, in a first state, directing current in series from a first subportion to a first capacitor, wherein the voltage across the capacitor establishes a first voltage level across the module, in a second state, directing current from a first subportion through the first capacitor, a second subportion, a second capacitor, and third subportion, wherein the voltage across the first and second capacitors establishes a second voltage level across the module, and in a third state, directing current from the first subportion through a fourth subportion and third subportion without involving the first and second capacitors, which establishes a third voltage level across the module.
A method for delivering high voltage alternating current power as part of an
- electrical power distribution network comprising:
- implementing a plurality of series connected modules, wherein each module converts a high voltage DC voltage and current through use of a three step ladder across a first and second terminal of the module in response to selectively applied control signals that control six high power semiconductor switching elements in each module;
- and
- in each of the series connected modules, applying the control signals over time to establish at least one of the following three states:
- a first state wherein direct current flows through three high power semiconductor switching elements and two capacitors in response to which a first voltage level is established across the terminals of the module, a second state wherein direct current flows through two high power semiconductor switching elements, a capacitor, and a reverse biased diode in response to which a second voltage level is established across the terminals of the module, and third state wherein direct current flows through two high power semiconductor switching elements and a reverse biased diode and in response to which the third voltage level is established across the terminals of the module.
A voltage sourced converter that converts high voltage DC to high voltage AC in
- an electrical power distribution grid, comprising:
- a module that converts high voltage DC through use of a three step high voltage ladder, wherein the module comprises
- a first and second terminal;
- three pairs of insulated high power insulated bipolar gate transistors, wherein the pairs are connected in series and the middle pair is positioned at a reverse polarity in relation to its series connected high power insulated bipolar gate transistors;
- six reverse bias diode, each diode connected in parallel across one of the insulated bipolar gate transistors;
- two capacitors that are connected in parallel, wherein a first capacitor is connected between the first and second pairs of high power insulated bipolar gate transistors and a second capacitor is connected between the second and third pairs of high power insulated bipolar gate transistors.
A high voltage power distribution grid comprising:
- a plurality of voltage sourced converters that distribute high voltage DC or high voltage AC to AC or DC components of the network, wherein one or more of the voltage sourced converters comprises means for converting a high voltage DC through use of a three step voltage ladder,
A method for transforming electric power from high voltage AC voltage and AC current to high voltage DC voltage and DC current and from high voltage DC voltage and DC current to high voltage AC voltage and AC current which comprises passing the power through voltage sourced converters (VSCs) whose legs are comprised all or in part with 3 step ladder bridge modules connected in series.
Dependencies are inferred from the claim text.