CONTROL DEVICE FOR ELECTRIC POWER CONVERSION APPARATUS

• US 20200136371A1
• Filed: 06/23/2017
• Published: 04/30/2020
• Est. Priority Date: 06/23/2017
• Status: Active Grant

• Current Assignee: Tmeic Corporation (Toshiba Corporation)
• Original Assignee: Toshiba Mitsubishi-Electric Industrial Systems Corporation (Toshiba Corporation)
• Inventors: TAWADA, Yoshihiro, INZUNZA FIGUEROA, Ruben Alexis, AMBO, Tatsuaki, KINOSHITA, Masahiro
• Granted Patent: US 11,018,495 B2
• Time in Patent Office: Days
• 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 3/16 responsive to fault current to earth, frame or mass with balanced or differential arrangement H02H3/26 ; monitoring earth connection H02H5/105
• CPC Class Codes: H02H 7/1222 responsive to abnormalities in the input circuit, e.g. transients in the DC input
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 7/5387 in a bridge configuration
• CPC Class Codes: H02M 7/53871 with automatic control of output voltage or current
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

A control device for an electric power conversion apparatus, the control device detecting occurrence of an earth fault in a direct-current path in a system in which the direct-current path between a solar cell module and an electric power conversion apparatus is grounded, is provided. The control device for the electric power conversion apparatus includes: a grounding control unit configured to, in a system in which a direct-current path between a solar cell module and an electric power conversion apparatus is grounded via a switch, control a switch; and an earth fault determination unit configured to, when the switch is open under the controlled of the grounding control unit, detect whether or not an earth fault has occurred in the direct-current path.

Claims

1. A control device for an electric power conversion apparatus, the control device comprising:

a grounding control unit configured to, in a system in which a direct-current path between a solar cell module and an electric power conversion apparatus is grounded via a switch, control the switch;

a direct-current voltage detection unit configured to detect a direct-current voltage output from the solar cell module; and

an earth fault determination unit configured to, when the switch is open under the control of the grounding control unit, determine whether or not an earth fault has occurred in the direct-current path,

wherein during a gradual decrease of the value of the direct-current voltage detected by the direct-current voltage detection unit to zero, when the direct-current voltage detection unit detects the direct-current voltage having a value that is smaller than a preset threshold value and the grounding control unit determines that a current time is a time in a period of transition from day to night based on a length of time passed from a last earth fault determination, the grounding control unit opening the switch and subsequently closing the switch before the value of the direct-current voltage detected by the direct-current voltage detection unit becomes zero.

2. The control device for an electric power conversion apparatus according to claim 1, comprising a direct-current voltage detection unit configured to detect a direct-current voltage output from the solar cell module,

wherein if a value of the direct-current voltage detected by the direct-current voltage detection unit is smaller than a preset threshold value, the grounding control unit opens the switch.

3-6. -6. (canceled)