BALANCING AND/OR DISCHARGE RESISTOR ARRANGEMENTS

• US 20160373022A1
• Filed: 02/25/2015
• Published: 12/22/2016
• Est. Priority Date: 02/26/2014
• Status: Active Grant

• Current Assignee: General Electric Technology GmbH (GE Aerospace)
• Original Assignee: Alstom Technology Ltd. (Alstom SA)
• Inventors: Outram, John Lewis
• Granted Patent: US 10,110,142 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02M 1/088 for the simultaneous control of series or parallel connected semiconductor devices
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 1/322 Means for rapidly discharging a capacitor of the converter for protecting electrical components or for preventing electrical shock
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H02M 7/06 using discharge tubes without control electrode or semiconductor devices without control electrode
• CPC Class Codes: H02M 7/217 using semiconductor devices only
• CPC Class Codes: H02M 7/4835 comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage
• CPC Class Codes: H03K 17/102 in field-effect transistor switches
• CPC Class Codes: H05K 5/0256 of interchangeable modules or receptacles therefor, e.g. cartridge mechanisms

Abstract

Circuits comprising at least one energy storage device, a resistor and switch arranged in series with the resistor are described. The energy storage device is arranged in parallel with the series connection of the switch and the resistor, and the switch is arranged to selectively switch the resistor into a parallel connection to the energy storage device. In some examples, the switch comprises a series connection of semiconductor switching elements. In some examples, the circuit may comprise a sub-module for use in a multilevel modular converter.

Claims

1. A sub-module for use in a multilevel modular converter, the sub-module comprising:

an energy storage device;

a resistor; and

a switch arranged in series with the resistor, the switch comprising a series of semiconductor switching elements,

wherein the energy storage device is arranged in parallel the switch and the resistor, and the switch is arranged to selectively position the resistor into a parallel connection with the energy storage device.

2. sub-module of claim 1, wherein the sub-module is configured to be controlled by a controller, and the resistor is chosen so as to draw current which exceeds that drawn by the controller.

3. The sub-module of claim 1, wherein the series of switching elements is arranged such that a change in switching state of one switching element in the series provides a switching signal for a subsequent switching element in the series.

4. The sub-module of claim 3, further comprising a divider positioned between at least one of the switching elements in the series, wherein the divider is arranged to divide the voltage at the output of a preceding switching element such that a proportion of the voltage at the output of the preceding switching element provides a switching signal to a subsequent switching element.

5. The sub-module of claim 4, wherein the divider comprises a first resistance and a second resistance.

6. The sub-module of claim 5, wherein the divider comprises a first capacitance and a second capacitance in association with the first and second resistances, respectively.

7. The sub-module of claim 6, wherein a ratio of the first and second capacitances is approximately equal to the reciprocal of the ratio of the first and second resistances.

8. The sub-module of claim 3, further comprising a divider positioned across at least two switching elements, the divider being arranged to share a voltage across the switching elements.

9. The sub-module of claim 1, wherein a first switching element is switched directly by a switching signal.

10. The sub-module of claim 1, wherein the switch is a normally on switch.

11. The sub-module of claim 1, wherein at least one switching element comprises a JFET or a MOSFET.

12. A multilevel modular converter comprising:

a plurality of sub-modules, each sub-module comprising;

an energy storage device;

a resistor; and

a switch arranged in series with the resistor, the switch comprising a series connection of semiconductor switching elements,

wherein the energy storage device is arranged in parallel with the switch and the resistor, and

at least one controller configured to operate the switch of at least one sub-module to position the resistor into a parallel connection with the energy storage device,

wherein the controller operates the switch to shutdown the converter, to block energy flowing to at least one sub-module, or to correct a voltage imbalance between the one or more of the sub-modules.

13. A method of balancing voltages in a circuit comprising a series connection of capacitors, the method comprising:

providing at least one series connection of a resistor and a switch;

arranging the at least one capacitor of the series connection of capacitors in parallel with a series connection of a resistor and the switch; and

switching at least one resistor into or out of the circuit in order to selectively balance the voltage across the series connection of capacitors.

14. The method of claim 13, wherein at least one switch comprises a series connection of switching elements.

15. The method of claim 13, which comprises switching a resistor into the circuit when the voltage of a capacitor connected in parallel thereto exceeds a first threshold voltage.

16. The method of claim 13 which comprises switching a resistor out of the circuit when the voltage of a capacitor connected in parallel thereto falls below a second voltage threshold.

17. The method of claim 13 which comprises a method of balancing capacitors within sub-modules of a multilevel modular converter.

19. The method of claim 13 further comprising switching the resistor into a parallel connection with the energy storage device to shutdown the converter, to block energy flowing to at least one sub-module, or to correct a voltage imbalance between the one or more of the sub-modules.

18. (canceled)