Storage battery system and method of controlling the same

• US 9,209,639 B2
• Filed: 06/19/2013
• Issued: 12/08/2015
• Est. Priority Date: 07/13/2012
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: Nishikawa, Kazufumi, Matsumura, Kohji
• Primary Examiner(s): Kik, Phallaka
• Application Number:
  US14/343,184
• Publication Number:
  US 20140247014A1
• Time in Patent Office: 902 Days
• Field of Search: 320/126, 320/134, 320/136, 320/156, 320/161, 320/162, 320/124, 307/56, 307/82, 307/150, 340/636.13, 340/636.15, 324/433, 324/434
• US Class Current: 1/1
• CPC Class Codes: G08B 21/00 Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/40 Synchronising a generator for connection to a network or to another generator
• CPC Class Codes: H02J 5/00 Circuit arrangements for transfer of electric power between ac networks and dc networks H02J3/36 takes precedence
• 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: H02M 1/0025 Arrangements for modifying reference values, feedback values or error values in the control loop of a converter
• CPC Class Codes: H02M 1/008 Plural converter units for generating at two or more independent and non-parallel outputs, e.g. systems with plural point of load switching regulators
• CPC Class Codes: H02M 1/325 with means for allowing continuous operation despite a fault, i.e. fault tolerant converters
• CPC Class Codes: H02M 3/04 by static converters
• 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
• CPC Class Codes: Y02P 90/50 Energy storage in industry with an added climate change mitigation effect

Abstract

A storage battery system includes: electric storage units; and DC-DC converters each provided between one of the electric storage units and a DC bus. Each of the DC-DC converters includes: a voltage sensor for detecting a voltage value at a connection point between the DC bus and the DC-DC converter; a second obtainment unit which obtains voltage values detected by the voltage sensors of the other DC-DC converters; and a control unit which, when a difference value between a statistic of the voltage values obtained by the second obtainment unit and the voltage value detected by the voltage sensor is not less than a predetermined threshold value, changes the voltage value detected by the voltage sensor, and controls an amount of charge in and an amount of discharge from a corresponding one of the electric storage units to approximate the changed voltage value to a predetermined target value.

Claims

1. A storage battery system comprising:

electric storage units connected with a common direct current (DC) bus in parallel, and each including at least one storage battery; and

voltage conversion units, each provided between one of the electric storage units and the DC bus, for controlling amounts of charge in and amounts of discharge from the electric storage units,

wherein each of the voltage conversion units includes;

a voltage sensor for detecting a voltage value at a connection point between the DC bus and the voltage conversion unit;

a communication unit configured to communicate with the other voltage conversion units;

an obtainment unit configured to obtain, via the communication unit, voltage values detected by the voltage sensors of the other voltage conversion units; and

a control unit configured to, when a difference value between (i) a statistic of the voltage values obtained by the obtainment unit and (ii) the voltage value detected by the voltage sensor is not less than a predetermined threshold value, approximate the voltage value detected by the voltage sensor to a predetermined target value by changing an amount of charge in and an amount of discharge from a corresponding one of the electric storage units.

2. The storage battery system according to claim 1,

wherein when the difference value is not less than the predetermined threshold value, the control unit of each of the voltage conversion units is configured to determine that the voltage sensor of the voltage conversion unit has failed.

3. The storage battery system according to claim 1,

wherein when determining that the voltage sensor of the voltage conversion unit has failed, the control unit of each of the voltage conversion units is configured to change the voltage value detected by the failed voltage sensor by substituting the statistic for the voltage value detected by the failed voltage sensor.

4. The storage battery system according to claim 1,

wherein when the difference value is not less than the predetermined threshold value, the control unit of each of the voltage conversion units is configured to weight the voltage value detected by the voltage sensor of the voltage conversion unit to correct the voltage value to be approximated to the statistic.

5. The storage battery system according to claim 1,

wherein the control unit of each of the voltage conversion units is configured to,

when the difference value is not less than a first threshold value, determine that the voltage sensor of the voltage conversion unit has failed, and substitute the statistic for the voltage value detected by the failed voltage sensor, and

when the difference value is less than the first threshold value and not less than a second threshold value smaller than the first threshold value, correct the voltage value detected by the voltage sensor of the voltage conversion unit to be approximated to the statistic.

6. The storage battery system according to claim 1, further comprising

a host controller which transmits a synchronization request signal for requesting the voltage sensor of each of the voltage conversion units to synchronize (i) a timing at which the voltage sensor of the voltage conversion unit detects a voltage value and (ii) a timing at which the voltage sensors of the other voltage conversion units detect voltage values.

7. The storage battery system according to claim 1,

wherein the statistic is an average value.

8. A method of controlling a storage battery system including electric storage units connected with a common direct current (DC) bus in parallel, and each including at least one storage battery;

and voltage conversion units, each provided between one of the electric storage units and the DC bus, for controlling amounts of charge in and amounts of discharge from the electric storage units, the method comprising;

detecting a voltage value at a connection point between the DC bus and each of the voltage conversion units by a voltage sensor of the voltage conversion unit;

obtaining voltage values detected by voltage sensors of the other voltage conversion units; and

when a difference value between (i) a statistic of the voltage values detected in the obtaining and (ii) the voltage value detected in the detecting is not less than a predetermined threshold value, approximating the voltage value detected by the voltage sensor to a predetermined target value by changing an amount of charge in and an amount of discharge from a corresponding one of the electric storage units.

9. A storage battery system comprising:

electric storage units connected with a common direct current (DC) bus in parallel, and each including at least one storage battery;

voltage conversion units, each provided between one of the electric storage units and the DC bus, for controlling amounts of charge in and amounts of discharge from the electric storage units;

voltage sensors each of which detects a voltage value at a connection point between the DC bus and one of the voltage conversion units; and

a control unit configured to control each of the voltage conversion units,

wherein when a difference value between (i) a voltage value detected by the voltage sensor corresponding to a particular voltage conversion unit and (ii) a statistic of voltage values detected by the voltage sensors corresponding to the voltage conversion units other than the particular voltage conversion unit is not less than a predetermined threshold value, the control unit is configured to approximate the voltage value detected by the voltage sensor corresponding to the particular voltage conversion unit to a predetermined target value by controlling each of the voltage conversion units.

10. A method of controlling a storage battery system including electric storage units connected with a common direct current (DC) bus in parallel, and each including at least one storage battery;

and voltage conversion units, each provided between one of the electric storage units and the DC bus, for controlling amounts of charge in and amounts of discharge from the electric storage units, the method comprising;

detecting a voltage value at a connection point between the DC bus and each of the voltage conversion units by a voltage sensor of the voltage conversion unit; and

when a difference value between (i) a voltage value detected by the voltage sensor corresponding to a particular voltage conversion unit and (ii) a statistic of voltage values detected by the voltage sensors corresponding to the voltage conversion units other than the particular voltage conversion unit is not less than a predetermined threshold value, approximating the voltage value detected by the voltage sensor corresponding to the particular voltage conversion unit to a predetermined target value by controlling each of the voltage conversion units.