Method of discharging at least one electrical energy storage unit, in particular a capacitor, of an electrical circuit

• US 9,742,346 B2
• Filed: 10/01/2013
• Issued: 08/22/2017
• Est. Priority Date: 10/01/2013
• Status: Active Grant

• Current Assignee: Valeo Systemes De Controle Moteur (Valeo SE)
• Original Assignee: Valeo Systemes De Controle Moteur (Valeo SE)
• Inventors: Esnault, Eric
• Primary Examiner(s): Luo, David S
• Application Number:
  US15/026,652
• Publication Number:
  US 20160241185A1
• Time in Patent Office: 1,421 Days
• Field of Search: 318139, 318 34, 318558
• CPC Class Codes: B60L 2270/00 Problem solutions or means not otherwise provided for
• CPC Class Codes: B60L 50/60 using power supplied by batteries in combination with fuel cells B60L50/75
• 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: H02P 31/00 Arrangements for regulating or controlling electric motors not provided for in groups H02P1/00 - H02P5/00, H02P7/00 or H02P21/00 - H02P29/00
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

Method of discharging at least one electrical energy storage unit of an electrical circuit (1), the electrical circuit (1) furthermore comprising a switching system (2) comprising a plurality of arms (3) each extending in parallel between a positive conductor (4) and a negative conductor (5) of a DC bus (7), each arm (3) comprising in series at least two switching cells (10), in which method, to discharge the capacitor (20, 40), a short-circuit between the positive conductor (4) and the negative conductor (5) of the DC bus (7) is produced in at least two of the arms (3) of the switching system (2) so as to allow the discharge current (I_DC) of the electrical energy storage unit to flow from said positive conductor (4) to said negative conductor (5).

Claims

1. A method for discharging at least one electrical energy storage unit comprising, a capacitor or a standalone source of electrical energy of an electrical circuit, the electrical circuit further comprising a switching system comprising a plurality of legs each extending in parallel between a positive conductor and a negative conductor of a DC bus, each leg comprising at least two switching cells in series, the method comprising:

a first step during which a short circuit is produced in a first leg and a second leg so as to define a path allowing the discharge current to flow between the positive conductor and the negative conductor of the DC bus; and

a second step during which a short circuit is produced in the second leg and another leg so as to define a path allowing the discharge current to flow between the positive conductor and the negative conductor of the DC bus.

2. The method as claimed in claim 1, further comprising:

a step prior to the first and second steps in which a short circuit is produced in the first leg of the switching system so that during the first step, the discharge current flows from the positive conductor to the negative conductor of the DC bus only through said first leg.

3. The method as claimed in claim 1, further comprising:

a step prior to the first and second steps in which a short circuit is produced in a third leg of the switching system so that during the first step, the discharge current flows from the positive conductor to the negative conductor of the DC bus only through said third leg.

4. The method as claimed in claim 1, in which the discharging of the electrical energy storage unit is carried out by successively producing multiple short circuits in the switching system between the positive conductor and the negative conductor of the DC bus, wherein as the electrical energy storage unit is being discharged, the duration for which each short circuit is produced increases.

5. The method as claimed in claim 1, in which the switching system forms a DC-AC voltage converter.

6. The method as claimed in claim 1, in which the switching system forms at least two interleaved DC-DC voltage converters.

7. The method as claimed in claim 1, in which each switching cell is controllable, wherein to form a short circuit in a leg between the positive conductor and the negative conductor of the DC bus, the switching cells of the corresponding leg are controlled.

8. The method as claimed in claim 1, in which each switching cell is controllable, wherein prior to the discharging of the electrical energy storage unit, all of the switching cells directly connected to the positive or negative conductor of the DC bus are controlled in such a way that they all have the same switching state and in which each short circuit is produced by controlling only the switching cells directly connected to the negative or positive conductor of the DC bus.

9. The method as claimed in claim 1, in which the electrical circuit further comprises a stator electrical winding of a rotating electric motor capable of being connected to the midpoint of each leg of the switching system.

10. The method as claimed in claim 9, in which a switch is interposed between each midpoint of the switching system and the stator electrical winding, wherein the switches disconnect the switching system from the stator electrical winding during the discharging of the electrical energy storage unit.

11. The method as claimed in claim 1, in which a capacitor is connected in parallel with the legs of the switching system and in which said capacitor is discharged.

12. The method as claimed in claim 1, in which the electrical circuit further comprises a standalone source of electrical energy in parallel with which a capacitor is connected, and a DC-DC voltage converter interposed between said standalone source of electrical energy and the switching system, in which method said capacitor is discharged.

13. A voltage converter for an air conditioning compressor of a vehicle, comprising:

a switching system comprising a plurality of legs each extending in parallel between a positive conductor and a negative conductor of a DC bus, each leg comprising at least two switching cells in series, and

a control unit configured so as to implement a method as claimed in claim 1.