METHODS AND APPARATUS FOR CONTROLLING POWER SWITCHES VIA A DIGITAL COMMUNICATION BUS

• US 20150023080A1
• Filed: 01/05/2012
• Published: 01/22/2015
• Est. Priority Date: 01/05/2012
• Status: Active Grant

• Current Assignee: Schneider Electric IT Corporation (Schneider Electric SE)
• Original Assignee: American Power Conversion Corporation (Schneider Electric SE)
• Inventors: Chambon, Patrick
• Granted Patent: US 9,490,689 B2
• Time in Patent Office: Days
• US Class Current: 363/131
• CPC Class Codes: H02M 1/0012 Control circuits using digital or numerical techniques in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873
• CPC Class Codes: H02M 1/084 using a control circuit common to several phases of a multi-phase system
• CPC Class Codes: H02M 1/0845 digitally controlled (or with digital control)
• CPC Class Codes: H02M 1/38 Means for preventing simultaneous conduction of switches
• CPC Class Codes: H02M 7/4837 Flying capacitor converters
• CPC Class Codes: H02M 7/487 Neutral point clamped inverters
• CPC Class Codes: H02M 7/537 using semiconductor devices only, e.g. single switched pulse inverters
• CPC Class Codes: H02M 7/53873 with digital control
• CPC Class Codes: H03K 17/04 Modifications for accelerating switching

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.

Claims

1. A method for controlling a set of power switches operating as a power converter, the method comprising:

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);

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.

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

4. The method according to claim 1, wherein each 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 command frame and sent at different times via the same multiplexed communication bus.

5. The method according to claim 1, wherein each command frame includes a plurality of switch command bits, each switch command bit representing one of said switch commands, and an address field identifying the subset of power switches to which the switch command bits relate.

6. The method according to claim 5, 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.

7. The method according to claim 5, 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.

8. 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.

9. The method according to claim 8, wherein an error message is returned to the controller in the event that a switch command received via the serial communication channel results in a forbidden state.

10. The method according to claim 8, wherein said forbidden state can be 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.

11. The method according to claim 8, wherein said forbidden state can be a state in which a minimum dead time is not be provided in a leg of the power converter.

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

13. The method according to claim 1, further comprising:

in response to a received 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.

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

15. The method according to claim 1, further comprising:

sending from the controller two or more of the same command frames at different instants over separate communication channels.

16. 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;

send the command frames on a serial communication channel to a driver module associated with the respective power switch.

17. The controller according to claim 16, wherein the controller is configured to:

combine switch commands for different subsets of said power switches into different command frames and send different time via the same communication channel.

18. The controller according to claim 16, wherein the controller is configured to:

combine switch commands for power switches forming part of a single leg in the power converter into one command frame.

19. The controller according to claim 16, wherein each 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 command frame and sent at different times via the same multiplexed communication bus.

20. The controller according to claim 19, wherein each command frame includes a plurality of switch command bits, each bit representing one of said switch commands, and an address field identifying the subset of said power switches to which the command bits relate.

21. The controller according to claim 20, 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 communication bus.

22. The controller according to claim 20, 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 communication bus.

23. The controller according to claim 16, 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.

24. The controller according to claim 23, wherein said forbidden state can be 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.

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

26. The controller according to claim 16, wherein the serial communication channel is a low voltage differential signal bus.

27. The controller according to claim 16, wherein the controller is configured to:

receive a reply frame from at least one of the subset of said power switches over a first communication channel;

wherein the controller sends the command frames through a second communication channel.

28. The controller according to claim 27, wherein the controller sends the command frames through the second communication channel while the reply frame is sent to the controller over the first communication channel.

29. The controller according to claim 16, wherein the controller is configured to send two or more of the same command frames at different instants over separate communication channels.

45. A power converter apparatus, comprising:

at least one controller according to claim 16; and

at least one driver module according to claim 30.

30. A driver module for use in a power converter having a set of power switches, the driver module being configured to:

receive over a serial communication channel a series of multi-bit command frames from a controller, said multi-bit command frames including switch commands for its associated power switches, each command indicating a desired state of one of said power switches at a moment in time;

extract individual switch commands from the multi-bit command frames;

set the state(s) of the appropriate power switch(es).

31. The driver module according to claim 30, wherein the driver module is configured to receive different command frames at different time via the same communication channel;

wherein switch commands for different subsets of said power switches are combined in said different command frames.

32. The driver module according to claim 30, wherein switch commands for power switches forming part of a single leg in the power converter are combined in one command frame.

33. The driver module according to claim 30, wherein each command frame includes switch commands for power switches driven by a switch driver within a single driver module.

34. The driver module according to claim 30, wherein each command frame includes a plurality of switch command bits, each bit representing one of said switch commands, and an address field identifying the subset of power switches to which the command bits relate.

35. The driver module according to claim 34, 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.

36. The driver module according to claim 34, 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.

37. The driver module according to claim 30, wherein the driver module is configured to:

check said switch commands according to predetermined criteria defining forbidden switch states after receiving said switch commands.

38. The driver module according to claim 37, wherein the driver module is configured to:

send 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.

39. The driver module according to claim 37, wherein said forbidden switch state can be 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.

40. The driver module according to claim 37, wherein said forbidden switch state can be a state in which a minimum dead time is not be provided in a leg of the power converter.

41. The driver module according to claim 30, wherein the serial communication channel is a low voltage differential signal bus.

42. The driver module according to claim 30, wherein the driver module is configured to send a reply frame to the controller over a first communication channel, and receive the command frames through a second communication channel.

43. The driver module according to claim 42, wherein the driver module is configured to send the reply frame to the controller over the first communication channel while the controller sends the command frames through the second communication channel.

44. The driver module according to claim 30, wherein the driver module is configured to receive two or more of the same command frames from the controller at different instants over separate communication channels.