CAPACITOR CIRCUIT AND POWER CONVERSION CIRCUIT

• US 20110292686A1
• Filed: 12/02/2010
• Published: 12/01/2011
• Est. Priority Date: 06/03/2008
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited, Shizuki Electric Company Incorporated
• Original Assignee: Murata Manufacturing Co Limited, Shizuki Electric Company Incorporated
• Inventors: NISHIYAMA, Shigeki, KOBAYASHI, Shinichi, OKA, Shoji, OBARA, Kazuyoshi
• Granted Patent: US 8,531,850 B2
• Time in Patent Office: Days
• US Class Current: 363/13
• CPC Class Codes: H02M 1/14 Arrangements for reducing ripples from dc input or output
• CPC Class Codes: H02M 1/4266 using passive elements
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A capacitor circuit includes a first capacitor line including a film capacitor and a second capacitor line including a ceramic capacitor that are connected in parallel with each other. The second capacitor line includes an inductance element that is connected in series with the ceramic capacitor. The inductance element is set to a value such that a series resonant frequency of the first capacitor line and a series resonant frequency of the second capacitor line are matched.

Claims

1. A capacitor circuit comprising:

a first capacitor line including a first capacitor;

a second capacitor line connected in parallel with the first capacitor line, including a second capacitor, and having an electrical characteristic different from an electrical characteristic of the first capacitor line; and

a resonant frequency adjustment element arranged to adjust a reactance of at least one of the first and second capacitor lines so that a first series resonant frequency of the first capacitor line and a second series resonant frequency of the second capacitor line are matched at a particular frequency.

2. The capacitor circuit according to claim 1, wherein the particular frequency is set to a frequency at which a current value of a high-frequency signal flowing into the capacitor circuit is maximized in a frequency band of the high-frequency signal.

3. The capacitor circuit according to claim 1, wherein the resonant frequency adjustment element is an inductance element included in at least one of the first and second capacitor lines.

4. The capacitor circuit according to claim 1, wherein the resonant frequency adjustment element is arranged to adjust the reactance by adjusting an internal inductance of at least one of the first and second capacitors.

5. The capacitor circuit according to claim 1, further comprising an impedance adjustment element arranged to set an impedance of the first capacitor line at the particular frequency greater than an impedance of the second capacitor line at the particular frequency.

6. The capacitor circuit according to claim 5, wherein the impedance adjustment element is a resistance element connected in series with the first capacitor.

7. The capacitor circuit according to claim 1, wherein the first capacitor has an electrical characteristic different from an electrical characteristic of the second capacitor.

8. The capacitor circuit according to claim 7, wherein the first capacitor is a film capacitor, and the second capacitor is a ceramic capacitor.

9. A power conversion circuit comprising:

a conversion circuit including at least one of an alternating current-direct current conversion circuit arranged to convert direct-current power into alternating-current power or to convert alternating-current power into direct-current power and a direct-current conversion circuit arranged to convert direct-current power into a different direct-current power; and

a capacitor circuit according to claim 1;

wherein

the capacitor circuit is connected to a direct-current power side of the alternating current-direct current conversion circuit or to at least one of the direct-current power sides of the direct-current conversion circuit.