Switching circuit, control apparatus, and power generation system

• US 8,587,251 B2
• Filed: 03/20/2012
• Issued: 11/19/2013
• Est. Priority Date: 10/29/2009
• Status: Expired due to Fees

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakashima, Takeshi, Hagihara, Ryuzo, Abe, Takayoshi
• Primary Examiner(s): Tso, Edward
• Assistant Examiner(s): OMAR, AHMED H
• Application Number:
  US13/424,483
• Publication Number:
  US 20120176079A1
• Time in Patent Office: 609 Days
• Field of Search: 320/101
• US Class Current: 320/101
• CPC Class Codes: H01L 31/02021 for solar cells electrical connection means, e.g. junction boxes, specially adapted for structural association with photovoltaic modules H02S40/34
• CPC Class Codes: H01M 10/465 with solar battery as charging system
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A switching circuit capable of efficiently practically using power generated in a plurality of photovoltaic power generation modules is provided. The switching circuit is employed for a power generation system capable of switching a connection state between the plurality of power generation modules, for switching a first connection state where at least a part of the plurality of power generation modules are connected in series with each other, and a second connection state where at least a part of the plurality of power generation modules are connected in parallel with each other, or, the generated power output portion is connected to a storage portion so that generated power is supplied from one of the power generation module to the storage portion.

Claims

1. A switching circuit employed for a power generation system including a generated power output portion constituted to include a plurality of power generation modules generating power with renewable energy as well as a power converter and a storage portion supplied with power generated in said power generation modules and capable of switching a connection state between said plurality of power generation modules, for switching:

a first connection state where at least a part of said plurality of power generation modules are connected in series with each other, and

a second connection state where at least a part of said plurality of power generation modules are connected in parallel with each other, or, said generated power output portion is connected to said storage portion so that generated power is supplied from one of said power generation modules to said storage portion.

2. The switching circuit according to claim 1, comprising a switch circuit switching the connection state between said plurality of power generation modules, wherein

said switch circuit is formed to be capable of switching the connection state so that at least a part of said plurality of power generation modules are connected in series or in parallel with each other and to be capable of switching a connection target of said generated power output portion to said power converter or to said storage portion.

3. The switching circuit according to claim 2, wherein

said switch circuit includes a first switch circuit switching the connection state between said plurality of power generation modules and a second switch circuit switching said power converter or said storage portion as a connection target of said generated power output portion.

4. The switching circuit according to claim 2, wherein

said switch circuit is formed by a mechanical switch circuit, and

the switching circuit further comprises an electronic switch circuit capable of switching inflow and cutoff of current into said mechanical switch circuit, and

is formed to be capable of switching the connection state between said plurality of power generation modules by operating said mechanical switch circuit in a state where the current to said mechanical switch circuit is cut off by said electronic switch circuit.

5. The switching circuit according to claim 1, so formed that:

said generated power output portion is connected to said power converter in said first connection state, and

said generated power output portion is connected to said storage portion so that generated power output by said parallel-connected power generation modules is supplied to said storage portion in said second connection state.

6. The switching circuit according to claim 5, so formed as to connect all of said plurality of power generation modules in series with each other in said first connection state, as to connect a part of said plurality of power generation modules in parallel with each other in said second connection state, and as to connect said parallel-connected power generation modules to said storage portion.

7. The switching circuit according to claim 5, so formed as to connect said parallel-connected power generation modules to said storage portion without through a voltage converter in a case where said parallel-connected power generation modules are connected to said storage portion.

8. The switching circuit according to claim 1, so formed that the connection state between said plurality of power generation modules is switched on the basis of a current of generated power supplied to said storage portion, which is measured by a current measuring portion.

9. The switching circuit according to claim 8, so formed as to connect said generated power output portion and said storage portion with each other through a charging switch circuit capable of switching connection or cutoff of said generated power output portion and said storage portion, and

so formed that said generated power output portion and said storage portion are connected with each other or cut off and said first connection state and said second connection state are switched on the basis of said current of generated power supplied to said storage portion, which is measured by said current measuring portion.

10. A control apparatus employed for a power generation system comprising a generated power output portion constituted to include a plurality of power generation modules generating power with renewable energy and a switching portion switching a connection state between said plurality of power generation modules as well as a power converter and a storage portion supplied with power generated in said power generation modules, so controlling said switching portion as to switch:

a first connection state where at least a part of said plurality of power generation modules are connected in series with each other and said generated power output portion is connected to said power converter, and

a second connection state where at least a part of said plurality of power generation modules are connected in parallel with each other or said generated power output portion is connected to said storage portion so that generated power is supplied from one of said power generation modules to said storage portion.

11. The control apparatus according to claim 10, formed to be capable of acquiring a current of generated power supplied to said storage portion, which is measured by a current measuring portion, and

so controlling said switching portion as to switch said generated power output portion to said first connection state in a case where the current value measured by said current measuring portion is larger than a prescribed value.

12. The control apparatus according to claim 11, so controlling said switching portion as to switch said generated power output portion to said second connection state in a case where said current of generated power measured by said current measuring portion is not more than said prescribed value when charging said storage portion.

13. The control apparatus according to claim 11, formed to be capable of switch-controlling a charging switch circuit provided between said generated power output portion and said storage portion and capable of switching connection and cutoff of said generated power output portion and said storage portion, and

so controlling said switching portion as to connect said generated power output portion and said storage portion with each other by said charging switch circuit and as to switch said generated power output portion to said second connection state in a case where said current of generated power measured by said current measuring portion is not more than a prescribed value, and

as to cut off said generated power output portion and said storage portion by said charging switch circuit and as to switch said generated power output portion to said first connection state in a case where said current of generated power measured by said current measuring portion is larger than said prescribed value.

14. The control apparatus according to claim 11, wherein

said power generation system further includes a plurality of said generated power output portions,

said plurality of generated power output portions are so formed that the switching between said first connection state and said second connection state is switchable every said generated power output portion, and

the control apparatus controls the number of said generated power output portions connected to said storage portion by switching said generated power output portions to said second connection state on the basis of said current of generated power measured by said current measuring portion.

15. The control apparatus according to claim 11, so controlling said switching portion as to calculate a predicted value of current flowing to said storage portion in a case of switching said generated power output portion to said second connection state on the basis of said current of generated power measured by said current measuring portion and as to switch said generated power output portion to said second connection state on the basis of said predicted current value.

16. The control apparatus according to claim 10, formed to be capable of acquiring a voltage detected by a voltage detection portion detecting voltage of said generated power output portion, and

determining a switching situation of the connection state by said switching portion on the basis of the voltage detected by said voltage detection portion.

17. A power generation system comprising:

a first generated power output portion constituted to include a plurality of power generation modules generating power with renewable energy and a switching portion switching a connection state between said plurality of power generation modules; and

a power converter and a storage portion supplied with power generated in said power generation modules, wherein

said switching portion is formed to be capable of switching;

a first connection state where at least a part of said plurality of power generation modules are connected in series with each other and said first generated power output portion is connected to said power converter, and

a second connection state where at least a part of said plurality of power generation modules are connected in parallel with each other, or, said generated power output portion is connected to said storage portion so that generated power is supplied from one of said power generation modules to said storage portion.

18. The power generation system according to claim 17, further comprising:

a plurality of said first generated power output portions, and

a control portion controlling switching of the connection state between said plurality of power generation modules by said switching portion, wherein

each of said plurality of first generated power output portions is so formed that the connection state between said plurality of power generation modules in each said first generated power output portion is individually switchable, and

the power generation system is so formed that the connection state between said plurality of power generation modules is controlled by said control portion.

19. The power generation system according to claim 17, further comprising a second generated power output portion constituted to include said plurality of power generation modules connected in series with each other, and so formed that:

said second generated power output portion is connected to said power converter, and

said first generated power output portion and said second generated power output portion are connected in parallel with each other when taking the first connection state where said first generated power output portion is connected to said power converter.

20. The power generation system according to claim 17, wherein

said switching portion includes a switch circuit switching the connection state between said plurality of power generation modules, and

said switch circuit is formed to be capable of switching the connection state so that at least a part of said plurality of power generation modules are connected in series or in parallel with each other and to be capable of switching a connection target of said generated power output portion to said power converter or to said storage portion in association with the switching of said connection state.

21. The power generation circuit according to claim 17, so formed as to take said first connection state so that power generated by said power generation modules is supplied to said power converter in normal operation, and

as to take said second connection state so that power generated by said power generation modules is supplied to said storage portion in unnormal operation.

22. The power generation system according to claim 17, wherein

a load is connected to said storage portion, and

the power generation system is so formed that power stored in said storage portion is supplied to said load in said first connection state, and

power generated by said parallel-connected power generation modules and power stored in said storage portion are supplied to said load in said second connection state.

23. The power generation system according to claim 17, wherein

said power generation modules are photovoltaic power generation modules,

said power converter is an inverter,

said photovoltaic power generation modules are connected to a power grid through said inverter,

a load is connected to said storage portion, and

the power generation system is formed to be switched to said second switching state so that power generated by said parallel-connected power generation modules and power stored in said storage portion are supplied to said load in a case where there is a possibility that power stored in said storage portion is not enough to supply for said load, and

to be switched to said first connection state so that power generated by said photovoltaic power generation modules is reversely flowable into said power grid through said inverter while power stored in said storage portion is supplied to said load in a case where power supplied to said load can be covered with power stored in said storage portion.