Inverter system

• US 7,598,748 B2
• Filed: 07/17/2003
• Issued: 10/06/2009
• Est. Priority Date: 07/22/2002
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Tanaka, Masaru, Hachisuka, Seiji, Senba, Minoru, Yadoori, Shuuichi
• Primary Examiner(s): Nguyen; Vincent Q
• Assistant Examiner(s): ZHU, JOHN X
• Application Number:
  US10/620,597
• Publication Number:
  US 20040012381A1
• Time in Patent Office: 2,273 Days
• Field of Search: 324/522, 324/127, 324/750, 324/529
• US Class Current: 324/522
• CPC Class Codes: G01R 15/18 using inductive devices, e.g. transformers
• CPC Class Codes: G01R 31/42 AC power supplies
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: G01R 31/54 Testing for continuity
• CPC Class Codes: G09G 2330/04 Display protection
• CPC Class Codes: G09G 3/006 Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: H01F 38/30 Constructions
• CPC Class Codes: H02H 1/0007 concerning the detecting means in general G01R or other subclasses of G01; reed switches H01H71/2445
• CPC Class Codes: H02H 1/0015 Using arc detectors
• CPC Class Codes: H02H 7/122 for inverters, i.e. dc/ac converters
• CPC Class Codes: H05B 41/2851 for protecting the circuit against abnormal operating conditions
• CPC Class Codes: H05B 41/2855 against abnormal lamp operating conditions

Abstract

An inverter system which converts DC input into AC output and supplies the AC output to a load such as an FL tube detects change in a circuit current due to anomaly such as discharge without contacting with a current route. Relating to an inverter which converts DC input into AC output and supplies the AC output to a load, change in a circuit current of the inverter is detected through the medium of magnetic flux change due to the change in the circuit current caused by discharge. For example, if change in a current occurs in the circuit current of the inverter by disconnection discharge or ground-fault discharge occurring in a current route including a load of the inverter, magnetic flux change occurs in circuit wiring and a space of a core gap of a transformer of the inverter. The change in the circuit current is detected through the medium of the magnetic flux change without contacting with the circuit wiring or the transformer.

Claims

1. A current detection method of an inverter that converts DC input into AC output and supplies the AC output to a load, comprising:

allowing magnetic flux change occurring to a circuit wiring to act on a detecting conductor arranged in the vicinity of the circuit wiring, the magnetic flux change occurring because of a change in a circuit current due to discharge, both the detecting conductor and the circuit wiring being printed on a same side of a circuit board, the detecting conductor having a straight-line segment disposed parallel to a straight-line segment of the circuit wiring such that the magnetic flux change that occurs to the circuit wiring is allowed to act on the straight-line segment of the detecting conductor; and

detecting the change in the circuit current through the medium of the magnetic flux change by the detecting conductor.

2. The current detection method of claim 1, further comprising:

rectifying and smoothing a current detected by the detecting conductor by acting of the magnetic flux change occurring to the circuit wiring; and

taking out a detection signal at a level representative of the change in the circuit current.

3. An anomaly detection method of an inverter that converts DC input into AC output and supplies the AC output to a load, comprising:

allowing magnetic flux change occurring to a circuit wiring to act on a detecting conductor arranged in the vicinity of the circuit wiring, the magnetic flux change occurring because of a change in a circuit current due to discharge, both the detecting conductor and the circuit wiring being printed on a same side of a circuit board, the detecting conductor having a straight-line segment disposed parallel to a straight-line segment of the circuit wiring such that the magnetic flux change that occurs to the circuit wiring is allowed to act on the straight-line segment of the detecting conductor; and

detecting the change in the circuit current through the medium of the magnetic flux change by the detecting conductor so as to detect based on a result of the detecting of the change in the circuit current whether or not anomaly exists in a current route including the load.

4. The anomaly detection method of claim 3, further comprising:

rectifying and smoothing a current detected by the detecting conductor by acting of the magnetic flux change occurring to the circuit wiring; and

taking out a detection signal at a level representative of the change in the circuit current.

5. A test method using an inverter that converts DC input into AC output and supplies the AC output to a load, comprising:

allowing magnetic flux change occurring to a circuit wiring to act on a detecting conductor arranged in the vicinity of the circuit wiring, the magnetic flux change occurring because of a change in a circuit current due to discharge, both the detecting conductor and the circuit wiring being printed on a same side of a circuit board, the detecting conductor having a straight-line segment disposed parallel to a straight-line segment of the circuit wiring such that the magnetic flux change that occurs to the circuit wiring is allowed to act on the straight-line segment of the detecting conductor; and

detecting the change in the circuit current through the medium of the magnetic flux change by the detecting conductor so as to decide based on a result of the detecting of the change in the circuit current whether or not anomaly exists in a current route including the load.

6. The test method of claim 5, further comprising:

rectifying and smoothing a current detected by the detecting conductor by acting of the magnetic flux change occurring to the circuit wiring; and

taking out a detection signal at a level representative of the change in the circuit current.

7. A current detection method, comprising:

allowing a magnetic flux change produced by a circuit current flowing through a circuit wiring to act on a detecting conductor located in a vicinity of the circuit wiring, both the detecting conductor and the circuit wiring being printed on a same side of a circuit board, the detecting conductor having a straight-line segment disposed parallel to a straight-line segment of the circuit wiring such that the magnetic flux change that occurs to the circuit wiring is allowed to act on the straight-line segment of the detecting conductor; and

detecting the change in the circuit current through the medium of the magnetic flux change on the detecting conductor.

8. The current detection method of claim 7, further comprising:

rectifying and smoothing a current detected by the detecting conductor by acting of the magnetic flux change occurring to the circuit wiring; and

taking out a detection signal at a level representative of the change in the circuit current.