Power supply system

Patent metadata

Field	Value
Publication number	US-9866022-B2
Application number	US-201214402255-A
Country	US
Kind code	B2
Filing date	May 24, 2012
Priority date	May 24, 2012
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

When an AC line of one local system and a power system are in a parallel-off state, a control device included in a power supply system causes local inverter devices of the local systems to operate in a parallel-off operation mode in which control is performed such that the voltage and frequency of power on the AC line is at a target voltage and a target frequency determined according to the state of charge of a power storage device. When a condition for switching to the connected state has been satisfied, the control device stops operation of the local inverter device in the parallel-off operation mode and causes a switch to the connected state by operating the interrupting device, and thereafter causes the local inverter device to operate in a charging operation mode used in charging the power storage device with supplementary power received from the power system.

First claim

The invention claimed is:

1. A power supply system comprising a plurality of local systems that each include an AC line to which a plurality of power consumers are connected, a power storage device, and a local inverter device that connects the power storage device and the AC line, comprising
a linking inverter device that connects the power storage device of one local system and the AC line of another local system between the local systems such that the plurality of local systems are electrically connected in series, the power supply system further comprising:
an interrupting device capable of switching the AC line of one local system among the plurality of local systems and an external power system that is separate from the plurality of local systems to one of a connected state and a disconnected state; and
a control device capable of controlling operation of the local inverter devices, the linking inverter device, and the interrupting device,
wherein when the AC line of the local system that can be connected to the external power system via the interrupting device and the external power system are in the disconnected state, the control device causes the local inverter device of each of the plurality of local systems to operate in a disconnected operation mode in which control is performed such that a voltage of power on the AC line is at a target voltage and such that a frequency of power on the AC line is at a target frequency determined according to a state of charge of the power storage device, and
wherein the power supply system is configured such that when the control device determines that a condition for switching to the connected state has been satisfied, with respect to the local system that can be connected to the external power system via the interrupting device, the control device stops operation of the local inverter device in the disconnected operation mode and causes a switch to the connected state by operating the interrupting device, and thereafter causes the local inverter device to operate in a charging operation mode used in charging the power storage device with supplementary power received from the external power system.

2. The power supply system according to claim 1 , wherein the control device determines that the condition for switching to the connected state has been satisfied once a set time is reached.

3. The power supply system according to claim 1 , wherein the control device determines that the condition for switching to the connected state has been satisfied once the state of charge of the power storage device of the local system that can be connected to the external power system via the interrupting device is less than a lower limit state of charge.

4. The power supply system according to claim 1 , wherein the control device changes the amount of supplementary power that the local inverter device is to receive from the external power system in the charging operation mode in accordance with a magnitude of the state of charge of the power storage device of the local system that can be connected to the external power system via the interrupting device at the time when the control device determined that the condition for switching to the connected state has been satisfied.

5. The power supply system according to claim 1 , wherein when the local inverter device is being caused to operate in the charging operation mode, the control device increases an amount of power transmitted by the linking inverter device between two adjacent local systems as the amount of supplementary power increases.

6. The power supply system according to claim 1 , wherein with respect to two mutually adjacent local systems that are electrically connected via one linking inverter device, the control device controls operation of the linking inverter device such that, based on the target frequencies determined according to the states of charge of the respective power storage devices, electric power is transmitted from the local system in which the state of charge of the power storage device is relatively higher to the local system in which the state of charge of the power storage device is relatively lower.

7. The power supply system according to claim 3 ,
wherein a natural energy power generation device whose power generation changes according to the weather is connected to the AC line of at least one local system among the plurality of local systems, and
the control device changes the magnitude of the lower limit state of charge according to the weather predicted for the future.

8. A power supply system comprising a plurality of local systems that each include an AC line to which a plurality of power consumers are connected, a power storage device, and a local inverter device that connects the power storage device and the AC line, comprising
a linking inverter device that connects the power storage device of one local system and the AC line of another local system between the local systems such that the plurality of local systems are electrically connected in series, the power supply system further comprising
a charging inverter device that connects the power storage device of one local system among the plurality of local systems and an external power system that is separate from the plurality of local systems, and can be used in charging of the power storage device with supplementary power received from the external power system; and
a control device that controls operation of the local inverter devices, the linking inverter device, and the charging inverter device,
wherein the control device controls the local inverter device of each of the plurality of local systems such that a voltage of power on the AC line is at a target voltage and such that a frequency of power on the AC line is at a target frequency determined according to a state of charge of the power storage device, and
wherein the power supply system is configured such that when the control device determines that a condition for starting charging has been satisfied, the control device causes the charging inverter device to operate in a charging operation mode in which the supplementary power is received from the external power system and used to charge the power storage device.

9. The power supply system according to claim 8 , wherein the control device determines that the condition for starting charging has been satisfied once a set time is reached.

10. The power supply system according to claim 8 , wherein the control device determines that the condition for starting charging has been satisfied once the state of charge of the power storage device of the local system connected to the external power system via the charging inverter device is less than a lower limit state of charge.

11. The power supply system according to claim 8 , wherein the control device changes the amount of supplementary power that the charging inverter device is to receive from the external power system in the charging operation mode in accordance with a magnitude of the state of charge of the power storage device of the local system connected to the external power system via the charging inverter device at the time when the control device determined that the condition for starting charging has been satisfied.

12. The power supply system according to claim 8 , wherein when the charging inverter device is being caused to operate in the charging operation mode, the control device increases an amount of power transmitted by the linking inverter device between two adjacent local systems as the amount of supplementary power increases.

13. The power supply system according to claim 10 ,
wherein a natural energy power generatio

Assignees

• Nakao Kunihiro
• YAKIRE Koji
• Hirai Tomoyuki
• Nagata Satoshi
• Osaka Gas Co Ltd
• Wind Eng Center Co Ltd

Inventors

• Nakao Kunihiro
• YAKIRE Koji
• Hirai Tomoyuki
• Nagata Satoshi

Classifications

• H02J7/52

  for charge balancing, e.g. equalisation of charge between batteries · CPC title

• H02M5/42

  by static converters · CPC title

• H02J3/46

  Controlling the sharing of generated power between the generators, sources or networks · CPC title

• H02J3/38

  Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel · CPC title

• H02J3/32 Primary

  using batteries or super capacitors with converting means · CPC title