CHARGING A CAPACITOR

• US 20150061382A1
• Filed: 08/30/2013
• Published: 03/05/2015
• Est. Priority Date: 08/30/2013
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Roessler, Werner
• Granted Patent: US 9,931,947 B2
• Time in Patent Office: Days
• US Class Current: 307/10.1
• CPC Class Codes: B60L 15/007 Physical arrangements or structures of drive train converters specially adapted for the propulsion motors of electric vehicles
• CPC Class Codes: B60L 2270/20 Inrush current reduction, i.e. avoiding high currents when connecting the battery
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

In one example, a method comprises alternately switching on a first switch connected in series with a capacitor and connected in parallel with a first capacitive element, and a second switch connected in series with the capacitor and connected in parallel with a second capacitive element. Aeries circuit with the first switch, the capacitor and the second switch may be coupled to supply nodes for receiving a supply voltage.

Claims

1. A method, comprising:

alternately switching on a first switch connected in series with a capacitor and connected in parallel with a first capacitive element, and a second switch connected in series with the capacitor and connected in parallel with a second capacitive element,

wherein a series circuit with the first switch, the capacitor and the second switch is coupled to supply nodes for receiving a supply voltage.

2. The method of claim 1, wherein alternately switching on the first switch, and the second switch comprise switching on only one of the first switch and the second switch at one time.

3. The method of claim 1,

wherein alternately switching on the first switch, and the second switch comprises a plurality of timely subsequent switching cycles,

wherein each of the plurality of switching cycles comprises:

switching on the first switch for a first on-period, and, after the first on-period, switching on the second switch for a second on-period.

4. The method of claim 3, wherein the first on-period and the second on-period are substantially equal.

5. The method of claim 3, wherein the first on-period and the second on-period are substantially fixed time periods.

6. The method of claim 3, wherein each of the plurality of switching cycles further comprises:

a first dead time after the first on-period and before the second on-period, and a second dead time after the second on-period and before the first on-period of a subsequent switching cycle.

7. The method of claim 1, further comprising:

detecting a voltage level of a voltage across the capacitor and switching on the first switch and the second switch when the voltage level has reached a predefined level.

8. The method of claim 7, wherein the predefined level is higher than 80% of a voltage level of the supply voltage.

9. The method of claim 1, wherein an inductor is connected in series with the capacitor.

10. The method of claim 9, wherein at least one rectifier element is connected in parallel with a series circuit comprising the capacitor and the inductor.

11. The method of claim 1, wherein at least one of the first capacitive element and the second capacitive element comprises a junction capacitor.

12. The method of claim 11, wherein at least one of the first switch and the second switch comprises a MOSFET, wherein the junction capacitor is formed by a body region and a drift region of the MOSFET.

13. The method of claim 1,

wherein a first rectifier element is connected in series with the first capacitive element, and a series circuit with the first rectifier element and the first capacitive element is coupled in parallel with the first switch, and

wherein a second rectifier element is connected in series with the second capacitive element, and a series circuit with the second rectifier element and the second capacitive element is coupled in parallel with the second switch.

14. The method of claim 13,

wherein the first capacitive element is coupled to the capacitor through the second rectifier element, and

wherein the second capacitive element is coupled to the capacitor through the first rectifier element.

15. An electronic circuit comprising:

an input configured to be connected to a power source, and an output configured to be connected to a capacitor,

a first switch connected in parallel with a first capacitive element and connected between the input and the output,

a second switch connected in parallel with a second capacitive element and connected between the input and the output, and

a control circuit configured to alternately switch on the first switch and the second switch.

16. The electronic circuit of claim 15, wherein the control circuit, is configured to switch on only one of the first switch and the second switch at one time.

17. The electronic circuit of claim 15,

wherein the control circuit, is configured to drive the first switch, and the second switch in a plurality of timely subsequent drive cycles, and

wherein the control circuit, in each drive cycle, is configured to

switch on the first switch for a first on-period, and, after the first on-period, to switching on the second switch for a second on-period.

18. The electronic circuit of claim 17, wherein the first on-period and the second on-period are substantially equal.

19. The electronic circuit of claim 17, wherein the first on-period and the second on-period are substantially fixed time periods.

20. The electronic circuit of claim 17, wherein the control circuit, in each drive cycle, is further configured to generate a first dead time after the first on-period and before the second on-period, and a second dead time after the second on-period and before the first on-period of a subsequent switching cycle.

21. The electronic circuit of claim 15, wherein the control circuit is further configured to detect a voltage level of a voltage at the output and to switch on the first switch and the second switch when the voltage level has reached a predefined level.

22. The electronic circuit of claim 21, wherein the predefined level is higher than 80% of a voltage level at the input.

23. The electronic circuit of claim 15, wherein at least one of the first capacitive element and the second capacitive element comprises a junction capacitor.

24. The electronic circuit of claim 23, wherein at least one of the first switch and the second switch comprises a MOSFET, wherein the junction capacitor is formed by a body region and a drift region of the MOSFET.

25. A switching circuit, comprising:

means for alternately switching on a first switch connected in series with a capacitor and connected in parallel with a first capacitive element, and a second switch connected in series with the capacitor and connected in parallel with a second capacitive element,

wherein a series circuit with the first switch, the capacitor and the second switch is coupled to supply nodes for receiving a supply voltage.