SUB-MODULE, PROTECTION UNIT, CONVERTER, AND CONTROL METHOD THEREOF
First Claim
1. A submodule, comprising an energy storage element, a first turn-off device, a second turn-off device, a third turn-off device, a freewheeling diode, and diodes respectively in antiparallel connection with the turn-off devices, characterized in that, either of the following two types of topology is adopted:
- i) a negative electrode of the first turn-off device is connected to a positive electrode of the second turn-off device, with the connection point being used as a first terminal of the submodule, a positive electrode of the first turn-off device is connected to a negative electrode of the second turn-off device through the energy storage element, and a negative electrode of the third turn-off device is connected to the negative electrode of the second turn-off device;
one end of the freewheeling diode branch is connected to the positive electrode of the first turn-off device;
the other end of the freewheeling diode branch is connected to a positive electrode of the third turn-off device, with the connection point being used as a second terminal of the submodule; and
ii) a negative electrode of the third turn-off device is connected to a cathode of the diode, with the connection point being used as a first terminal of the submodule;
a positive electrode of the third turn-off device is connected to a positive electrode of the second turn-off device, a negative electrode of the second turn-off device is connected to a positive electrode of the first turn-off device, with the connection point being used as a second terminal of the submodule, and the positive electrode of the third turn-off device is connected to a negative electrode of the first turn-off device through the energy storage element;
as a series branch, the freewheeling diode has one end connected to the negative electrode of the first turn-off device and the other end connected to the negative electrode of the third turn-off device.
1 Assignment
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Accused Products
Abstract
Disclosed are a submodule structure formed of an energy storage element, a first turn-off device, a second turn-off device, a third turn-off device, a freewheeling diode, a series resistor, and diodes respectively in antiparallel connection with the turn-off devices, and a converter completely or partially formed of the submodules. Also disclosed are a relevant protection unit and a control method for the converter. The converter can be locked when a direct current (DC) fault occurs to prevent an alternating current (AC) system from injecting a fault current into a DC network, so that a transient fault of the DC network can be removed without tripping an AC line switch, thereby rapidly restarting the system. A charging resistor is comprised in the submodule so that a charging resistor disposed at an AC side of the converter can be reduced and even may not be disposed.
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Citations
19 Claims
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1. A submodule, comprising an energy storage element, a first turn-off device, a second turn-off device, a third turn-off device, a freewheeling diode, and diodes respectively in antiparallel connection with the turn-off devices, characterized in that, either of the following two types of topology is adopted:
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i) a negative electrode of the first turn-off device is connected to a positive electrode of the second turn-off device, with the connection point being used as a first terminal of the submodule, a positive electrode of the first turn-off device is connected to a negative electrode of the second turn-off device through the energy storage element, and a negative electrode of the third turn-off device is connected to the negative electrode of the second turn-off device;
one end of the freewheeling diode branch is connected to the positive electrode of the first turn-off device;
the other end of the freewheeling diode branch is connected to a positive electrode of the third turn-off device, with the connection point being used as a second terminal of the submodule; andii) a negative electrode of the third turn-off device is connected to a cathode of the diode, with the connection point being used as a first terminal of the submodule;
a positive electrode of the third turn-off device is connected to a positive electrode of the second turn-off device, a negative electrode of the second turn-off device is connected to a positive electrode of the first turn-off device, with the connection point being used as a second terminal of the submodule, and the positive electrode of the third turn-off device is connected to a negative electrode of the first turn-off device through the energy storage element;
as a series branch, the freewheeling diode has one end connected to the negative electrode of the first turn-off device and the other end connected to the negative electrode of the third turn-off device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19)
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9. A protection unit, used for a submodule of a voltage source multi-level converter and comprising a first terminal and a second terminal, characterized in that, the first terminal of the protection unit is connected to a first terminal of the submodule and the second terminal of the protection unit is connected to a second terminal of the submodule;
- the protection unit has any one or more of the following four topological structures;
i) the protection unit is formed of a thyristor, wherein a cathode of the thyristor is the first terminal of the protection unit and an anode of the thyristor is the second terminal of the protection unit; ii) the protection unit is formed of a high-speed switch, wherein one end of the high-speed switch is the first terminal of the protection unit and the other end of the high-speed switch is the second terminal of the protection unit; iii) the protection unit is formed of a thyristor and a high-speed switch connected to each other in parallel, wherein a cathode of the thyristor is the first terminal of the protection unit, an anode of the thyristor is the second terminal of the protection unit, one end of the high-speed switch is connected to the cathode of the thyristor, and the other end of the high-speed switch is connected to the anode of the thyristor; and iv) the protection unit is formed of at least two antiparallel thyristors and a high-speed switch connected to each other in parallel, wherein one end of the antiparallel thyristors is the first terminal of the protection unit, the other end of the antiparallel thyristors is the second terminal of the protection unit, one end of the high-speed switch is connected to the first terminal of the protection unit, and the other end of the high-speed switch is connected to the second terminal of the protection unit. - View Dependent Claims (10)
- the protection unit has any one or more of the following four topological structures;
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13. The converter according to chum 12, characterized in that, in the additional submodule, a negative electrode of the first turn-off device is connected to a positive electrode of the second turn-off device, with the connection point being used as a first terminal, and a negative electrode of the second turn-off device is used as a second terminal.
Specification