Power conversion apparatus, control system, and control method

• US 9,876,391 B2
• Filed: 04/01/2014
• Issued: 01/23/2018
• Est. Priority Date: 04/01/2013
• Status: Active Grant

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Corporation
• Inventors: Kuwahara, Hitoshi
• Primary Examiner(s): Wells, Kenneth B
• Application Number:
  US14/781,892
• Publication Number:
  US 20160043597A1
• Time in Patent Office: 1,393 Days
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02M 3/04 by static converters
• CPC Class Codes: H02M 7/44 by static converters
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02P 90/50 Energy storage in industry with an added climate change mitigation effect

Abstract

PCS 400 operates in any one of a standard mode and a charging mode within a plurality of operation modes at a time when PV 100 operates. The plurality of operation modes include the standard mode in which an output of the PV 100 is converted into AC power and the AC power is supplied to grid 1 and/or load 300 and the charging mode in which the output of the PV 100 is supplied to storage battery 200. An output voltage of the DC/DC converter 410 is different in the standard mode and in the charging mode.

Claims

1. A power conversion apparatus that operates while switching a plurality of operation modes, the plurality of operation modes including a first mode in which an output of the power generation apparatus is converted into AC power and the AC power is supplied to at least one of a grid and a load and a second mode in which the output of the power generation apparatus is supplied to a storage battery, the power conversion apparatus comprising:

a DC/DC converter connected to a power source line of the power generation apparatus; and

a DC/AC converter connected to the DC/DC converter through a first power line, wherein

the DC/DC converter is connected to the storage battery through a second power line which branches from the first power line,

in the first mode, the DC/DC converter outputs DC power having a first voltage determined according to a setting voltage of the grid, and

in the second mode, the DC/DC converter outputs DC power having a second voltage, which is lower than the first voltage, determined according to a charge battery of the storage battery.

2. The power conversion apparatus according to claim 1, further comprising:

a control unit that selects any one of the first mode and the second mode among the plurality of operation modes in a time-division manner.

3. The power conversion apparatus according to claim 2, wherein

the load is a load that performs an intermittent operation, and

at the time when the power generation apparatus operates, the control unit selects any one of the first mode and the second mode according to an operation state of the load in a case where the power conversion apparatus is in a disconnected state with the grid.

4. The power conversion apparatus according to claim 3, wherein

at the time when the power generation apparatus operates, the control unit selects the second mode in a case where the power conversion apparatus is in the disconnected state with the grid and the power consumption of the load is smaller than a first threshold.

5. The power conversion apparatus according to claim 4, wherein

at the time when the power generation apparatus operates, the control unit selects the first mode in a case where the power conversion apparatus is in the disconnected state with the grid and the power consumption of the load is larger than the first threshold.

6. The power conversion apparatus according to claim 5, wherein

the control unit selects the second mode in a case where a predetermined time elapses from a time when the power consumption of the load exceeds the first threshold.

7. The power conversion apparatus according to claim 4, wherein

at the time when the power generation apparatus operates, the control unit selects the second mode in a case where the power conversion apparatus is in the disconnected state with the grid, and the power consumption of the load is smaller than the first threshold and the output of the power generation apparatus is lower than a second threshold.

8. The power conversion apparatus according to claim 4, wherein

at the time when the power generation apparatus operates, the control unit selects the second mode in a case where the power conversion apparatus is in the disconnected state with the grid, and the power consumption of the load is smaller than the first threshold and the output of the power generation apparatus is larger than a second threshold.

9. The power conversion apparatus according to claim 2, wherein

at the time when the power generation apparatus operates, the control unit selects the first mode in a case where electric energy accumulated in the storage battery is larger than a predetermined value.

10. The power conversion apparatus according to claim 2, wherein

at the time when the power generation apparatus operates, the control unit selects any one of the first mode and the second mode according to a voltage of the grid in a case where the power conversion apparatus is in a connected state with the grid.

11. A control system comprising:

a power conversion apparatus that operates while switching a plurality of operation modes; and

a control apparatus that controls the power conversion apparatus, wherein

the plurality of operation modes includes a first mode in which an output of the power generation apparatus is converted into AC power and the AC power is supplied to at least one of a grid and a load and a second mode in which the output of the power generation apparatus is supplied to a storage battery, wherein

the power conversion apparatus comprises;

a DC/DC converter connected to a power source line of the power generation apparatus, and

a DC/AC converter connected to the DC/DC converter through a first power line, wherein

the DC/DC converter is connected to the storage battery through a second power line which branches from the first power line,

in the first mode, the DC/DC converter outputs DC power having a first voltage determined according to a setting voltage of the grid, and

in the second mode, the DC/DC converter outputs DC power having a second voltage, which is lower than the first voltage, determined according to a charge battery of the storage battery.

12. A control method applied to a power conversion apparatus, the power conversion apparatus including a DC/DC converter connected to a power source line of a power generation apparatus and a DC/AC converter connected to the DC/DC converter through a first power line, the DC/DC converter being connected to a storage battery through a second power line which branches from the first power line, the control method comprising the steps of:

switching, in a time-division manner, a first mode in which the power conversion apparatus converts an output of the power generation apparatus into AC power and supplies the AC power to at least one of a grid and a load, and a second mode in which the output of the power generation apparatus is supplied to the storage battery;

in the first mode, outputting from the DC/DC converter DC power having a first voltage determined according to a setting voltage of the grid, and

in the second mode, outputting from the DC/DC converter DC power having a second voltage, which is lower than the first voltage, determined according to a charge battery of the storage battery.