Methods and apparatus for controlling power switches via a digital communication bus

Patent metadata

Field	Value
Publication number	US-9490689-B2
Application number	US-201214370824-A
Country	US
Kind code	B2
Filing date	Jan 5, 2012
Priority date	Jan 5, 2012
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

Methods and apparatus are provided that can be used to control a set of power switches operating as a power converter. The method comprises providing a set of power switches and at least one switch driver, each power switch being operable to connect and disconnect one of a set of input power line to an output power line, each switch driver setting the state(s) of an associated power switch or switches; generating by a controller a set of switch commands, each command indicating a desired state of a respective one of said power switches at a moment in time; sending each switch command from the controller to a driver module containing the switch driver associated with the respective power switch; receiving at each driver module switch commands for its associated power switch(es) and causing each switch driver to set the state(s) of the appropriate power switch(es) accordingly; wherein the step of sending said switch commands comprises multiplexing commands for at least a subset of said switches into a series of multi-bit command frames and transmitting said command frames on a serial communication channel, and wherein the step of receiving said switch commands comprises receiving said multi-bit command frames from said communication channel and extracting individual switch commands therefrom. The method and apparatus can be used for example in a UPS system.

First claim

The invention claimed is:

1. A method for controlling a set of power switches operating as a power converter, the method comprising:
providing the set of power switches and at least one switch driver, each power switch being operable to connect and disconnect one of a set of input power lines to an output power line, the at least one switch driver setting a state of an associated power switch or switches;
generating by a controller a set of switch commands, each of the switch commands indicating a desired state of a respective one of said power switches at a moment in time;
sending each of the switch commands from the controller to a driver module containing the at least one switch driver associated with the respective power switch;
receiving at the driver module the switch commands for the respective power switch; and
causing the at least one switch driver to set the state of the respective power switch;
wherein sending said switch commands comprises multiplexing commands for at least a subset of said power switches into a series of multi-bit command frames and transmitting said multi-bit command frames on a serial communication channel,
wherein each multi-bit command frame includes a plurality of switch command bits, each of the plurality of switch command bits representing one of said switch commands, and an address field identifying the subset of power switches to which the switch command bits relate, and
wherein receiving said switch commands comprises receiving said multi-bit command frames from said serial communication channel and extracting individual switch commands therefrom.

2. The method according to claim 1 , wherein switch commands for different subsets of said power switches are combined in different multi-bit command frames and sent at different times via the same serial communication channel.

3. The method according to claim 1 , wherein switch commands for power switches forming part of a single leg in the power converter are combined in one multi-bit command frame.

4. The method according to claim 1 , wherein each multi-bit command frame includes switch commands for power switches driven by a switch driver within a single driver module, while switch commands for power switches driven by switch drivers within a different driver module are combined in a different multi-bit command frame and sent at different times via the same serial communication channel.

5. The method according to claim 1 , wherein the address field identifies a subset of power switches driven by a single driver module comprising a plurality of switch drivers and having a single interface to said serial communication channel.

6. The method according to claim 1 , wherein the address field identifies a subset of power switches driven by different single driver modules, each driver module comprising a plurality of switch drivers and having a single interface to said serial communication channel.

7. The method according to claim 1 , further comprising:
after receiving said switch commands, checking said switch commands according to predetermined criteria defining forbidden switch states.

8. The method according to claim 7 , further comprising:
sending an error message to the controller in the event that a switch command received via the serial communication channel results in a forbidden switch state.

9. The method according to claim 7 , wherein said forbidden switch states include a state in which two power switches in a leg of the power converter are on at a same time, leading to a short circuit of said input power line.

10. The method according to claim 7 , wherein said forbidden switch states include a state in which a minimum dead time is not provided in a leg of the power converter.

11. The method according to claim 1 , wherein the serial communication channel is a low voltage differential signal bus.

12. The method according to claim 1 , further comprising:
in response to a received multi-bit command frame, sending from at least one of the subset of power switches a reply frame to the controller over a first communication channel;
wherein the controller sends the command frames through a second communication channel.

13. The method according to claim 12 , wherein the reply frame is sent to the controller over the first communication channel while the controller sends the multi-bit command frames through the second communication channel.

14. The method according to claim 1 , further comprising:
sending from the controller two or more of the same multi-bit command frames at different instants over separate communication channels.

15. A controller for use in a power converter having a set of power switches, the controller being configured to:
generate a set of switch commands, each switch command indicating a desired state of one of said power switches of the power converter at a moment in time;
multiplex commands for at least a subset of said power switches into a series of multi-bit command frames, wherein each multi-bit command frame includes a plurality of switch command bits, each of the plurality of switch command bits representing one of said switch commands, and an address field identifying the subset of said power switches to which the plurality of switch command bits relate; and
send the multi-bit command frames on a serial communication channel to a driver module associated with at least one of the subset of said power switches.

16. The controller according to claim 15 , wherein the controller is configured to:
combine switch commands for different subsets of said power switches into different multi-bit command frames; and
send the multi-bit command frames at different times via the same serial communication channel.

17. The controller according to claim 15 , wherein the controller is configured to:
combine switch commands for power switches forming part of a single leg in the power converter into one multi-bit command frame.

18. The controller according to claim 15 , wherein each multi-bit command frame includes switch commands for power switches driven by a switch driver within a single driver module, while switch commands for power switches driven by switch drivers within a different driver module are combined in a different multi-bit command frame and sent at different times via the same serial communication channel.

19. The controller according to claim 15 , wherein the address field identifies a subset of switches driven by a single driver module comprising a plurality of switch drivers and having a single interface to said serial communication channel.

20. The controller according to claim 15 , wherein the address field identifies a subset of switches driven by different single driver modules, each driver module comprising a plurality of switch drivers and having a single interface to said serial communication channel.

21. The controller according to claim 15 , wherein the controller is configured to receive an error message in the event that a switch command received via the serial communication channel results in a forbidden state.

22. The controller according to claim 21 , wherein said forbidden state includes a state in which two power switches in a leg of the power converter are on at a same time, leading to a short circuit of an input power line.

23. The controller according to claim 21 , wherein said forbidden state includes a state in which a minimum dead time is not provided in a leg of the power converter.

Assignees

• Chambon Patrick
• Schneider Electric It Corp

Inventors

• Chambon Patrick

Classifications

• H02M7/487

  Neutral point clamped inverters · CPC title

• H02M1/0845

  digitally controlled (or with digital control) · CPC title

• H02M7/53873

  with digital control · CPC title

• H02M1/38

  Means for preventing simultaneous conduction of switches · CPC title

• H02M2001/0012

  Electricity · mapped topic