Converter device comprising at least five DC voltage levels and uninterruptible power supply provided with said device

• US 20110110136A1
• Filed: 10/20/2010
• Published: 05/12/2011
• Est. Priority Date: 11/06/2009
• Status: Active Grant

• Current Assignee: Mge Ups
• Original Assignee: Mge Ups
• Inventors: Lacarnoy, Alain
• Granted Patent: US 8,488,336 B2
• Time in Patent Office: Days
• US Class Current: 363/127
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02M 7/483 Converters with outputs that each can have more than two voltages levels
• CPC Class Codes: H02M 7/797 using semiconductor devices only

Abstract

A multi-level converter to at least convert an AC switched voltage available on a switched voltage point into at least five DC voltage levels available on positive and negative DC voltage lines, said converter comprising two separate switching units to convert respectively positive and negative half-waves of said switched voltage, connected to the DC voltage lines respectively presenting positive and negative DC voltage levels, and wherein each switching unit comprises a switching point connected to said switched voltage point by means of change-over means.

An uninterruptible power supply comprising said converter.

Claims

1. Multi-level converter device to at least convert an AC switched voltage available on a switched voltage point into at least five DC voltage levels available on DC voltage lines, said lines including a reference voltage line and as many lines having positive voltage levels as lines having negative voltage levels,

wherein said device comprises two separate switching units to convert half-waves of said respectively positive and negative switched voltage into at least two respectively positive and negative DC voltage levels, said switching units being connected to said reference voltage line and to the DC voltage lines respectively presenting a positive voltage level and a negative voltage level, and

wherein each switching unit comprises a switching point connected to said switched voltage point by means of change-over means, and switching groups connected between said lines to which said switching unit is connected and said switching point.

2. Device according to claim 1, wherein switching unit comprises:

a maximum voltage branch connected between the switching point of said switching unit and the DC voltage line connected to said switching unit having an extreme voltage level, said maximum voltage branch being provided with a first switching group,

at least one intermediate voltage branch connected between said switching point and the at least one DC voltage line connected to said switching unit having an intermediate voltage level, said at least one intermediate voltage branch being provided with a second switching group, and

a minimum voltage branch connected between said switching point and the reference voltage line, said minimum voltage branch being provided with a third switching group.

3. Device according to claim 2, wherein the second switching group is the same on each intermediate voltage branch of one and the same switching unit.

4. Device according to claim 1, wherein the change-over means comprise a thyristor connected between the switched voltage point and the switching point of each switching unit, each thyristor being directed to make the current flow in a direction enabling the electric power available on said AC voltage point to be transferred to the switching point of each switching unit.

5. Device according to claim 1, wherein the change-over means comprise a diode connected between the switched voltage point and the switching point of each switching unit, each diode being directed to make for the current flow in a direction enabling the electric power available on said AC voltage point to be transferred to the switching point of each switching unit.

6. Device according to claim 5, wherein the change-over means further comprise a transistor directed to conduct the current in the opposite direction.

7. Device according to claim 2, wherein the switching groups of each branch at least enable the electric power to be transferred from the switching point to the DC voltage lines to which said branches are connected to regulate the voltage levels on said lines.

8. Device according to claim 7, wherein the second switching group of each intermediate voltage branch and of each switching unit is designed to enable conduction of a current in at least a first direction when the amplitude of the voltage on the switching point of said switching unit is greater than the amplitude of the voltage on the line to which said branch is connected, and to turn said current off whatever the amplitude of the voltage on the switching point.

9. Device according to claim 8, wherein the second switching group of each intermediate voltage branch and of each switching unit is designed to further enable conduction of a current in an opposite direction to the first direction when the amplitude of the voltage on the switching point of said switching unit is lower than the amplitude of the voltage on the line to which said branch is connected.

10. Device according to claim 8, wherein the second switching group of each intermediate voltage branch and of each switching unit comprises:

a transistor directed to enable conduction of a current in the first direction when the amplitude of the voltage on the switching point is greater than the amplitude of the voltage on the line to which said branch is connected,

at least one diode connected in series with said transistor and directed to let a current flowing in said first direction pass, and

a diode connected in parallel to said transistor and reverse-directed with respect to said transistor.

11. Device according to claim 10, wherein the second switching group of each intermediate voltage branch and of each switching unit further comprises a transistor directed to enable conduction of a current in the opposite direction to the first direction when the amplitude of the voltage on the switching point is lower than the amplitude of the voltage on the line to which said branch is connected.

12. Device according to claim 7, wherein the first switching group of each maximum voltage branch and of each switching unit comprises at least one diode directed to at least turn the current off in a second direction when the amplitude of the voltage on the switching point of said switching unit is lower than the amplitude of the voltage on the line to which said branch is connected.

13. Device according to claim 12, wherein the first switching group of each maximum voltage branch and of each switching unit further comprises a transistor designed to enable conduction of a current in an opposite direction to the second direction when the amplitude of the voltage on the switching point is lower than the amplitude of the voltage on the line to which said branch is connected.

14. Device according to claim 7, wherein the third switching group of each minimum voltage branch and of each switching unit is designed to enable conduction of a current in at least a third direction when the amplitude of the voltage on the switching point of said switching unit is greater than the amplitude of the voltage on the reference voltage line, and to let a current flow in an opposite direction to said third direction.

15. Device according to claim 14, wherein the third switching group of each intermediate voltage branch and of each switching unit comprises:

a transistor directed to enable conduction of a current in the third direction when the amplitude of the voltage on the switching point of said switching unit is greater than the amplitude of the voltage on the reference voltage line, and

a diode connected in parallel to said transistor and directed to let a current flowing in an opposite direction to said third direction pass.

16. Uninterruptible power supply comprising a power supply input on which an AC input voltage is applied, a rectifier connected to said input, two substantially DC voltage lines of opposite signs connected on output of said rectifier, an inverter connected to said substantially DC voltage lines and comprising an output designed to supply a backed-up voltage, wherein said inverter is a converter device according to claim 1 and supplies a backed-up AC voltage from the substantially DC voltages.