POWER CONVERSION SYSTEM, POWER CONVERTER, AND METHOD FOR DIAGNOSING STATE OF POWER STORAGE DEVICE

• US 20160336792A1
• Filed: 07/29/2016
• Published: 11/17/2016
• Est. Priority Date: 02/21/2014
• Status: Abandoned Application

• Current Assignee: Kabushiki Kaisha Yaskawa Denki
• Original Assignee: Kabushiki Kaisha Yaskawa Denki
• Inventors: TERAZONO, Katsushi
• Application Number:
  US15/222,951
• Publication Number:
  US 20160336792A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• 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 10/486 for measuring temperature
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 3/32 using batteries with converting means
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: H02M 3/33576 having at least one active switching element at the secondary side of an isolation transformer
• CPC Class Codes: H02M 3/3376 with automatic control of output voltage or current
• CPC Class Codes: H02M 5/42 by static converters
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

This disclosure discloses a power conversion system including a first power converter, a second power converter, and a power storage device. The second power converter includes a control signal generation part, a detection signal processing part, and a state diagnosis part. The control signal generation part is configured to perform at least one of superposition of a predetermined AC voltage on a DC voltage in a second DC power and superposition of a predetermined AC current on a DC current in the second DC power. The detection signal processing part is configured to detect at least one of a detection value of the DC voltage superposed with the AC voltage and a detection value of the DC current superposed with the AC current. The state diagnosis part is configured to diagnose a state of the power storage device based on the detection value.

Claims

1. A power conversion system comprising:

a first power converter configured to convert AC power from an AC power source to first DC power;

a second power converter configured to convert the first DC power from the first power converter to another second DC power having a different power value from the first DC power; and

a power storage device configured to store the second DC power from the second power converter,

the second power converter comprising;

a control signal generation part configured to perform at least one of superposition of a predetermined AC voltage on a DC voltage in the second DC power and superposition of a predetermined AC current on a DC current in the second DC power;

a detection signal processing part configured to detect at least one of a detection value of the DC voltage superposed with the AC voltage and a detection value of the DC current superposed with the AC current; and

a state diagnosis part configured to diagnose a state of the power storage device based on at least one of the detection value of the DC voltage and the detection value of the DC current.

2. The power conversion system according to claim 1,

wherein the control signal generation part is configured to generate and output a control signal in which an AC instruction whose frequency changes within a predetermined frequency range is superposed on a DC instruction on a side of the power storage device, and

wherein the state diagnosis part is configured to calculate a state quantity of the power storage device by an AC impedance method based on at least one of an AC voltage component value in the detection value of the DC voltage and an AC current component value in the detection value of the DC current.

3. The power conversion system according to claim 2,

wherein the control signal generation part is

configured to generate and output the control signal in which an AC voltage instruction in the AC instruction is superposed on a DC voltage instruction in the DC instruction when the power storage device is controlled so as to perform charge and discharge with constant voltage, and

configured to generate and output the control signal in which an AC current instruction in the AC instruction is superposed on a DC current instruction in the DC instruction when the power storage device is controlled so as to perform charge and discharge with constant current.

4. The power conversion system according to claim 3,

wherein the state diagnosis part is

configured to calculate at least one of a resistance value and capacitance of the power storage device as the state quantity, and

configured to diagnose a deterioration state of the power storage device based on at least one of the resistance value and the capacitance.

5. The power conversion system according to claim 4,

wherein the state diagnosis part is configured to diagnose an abnormality of the power storage device based on the resistance value.

6. The power conversion system according to claim 5,

wherein the state diagnosis part is configured to output an abnormality diagnosis signal when the state diagnosis part diagnoses as the abnormality.

7. The power conversion system according to claim 6, further comprising

a circuit breaker disposed on a DC line between the second power converter and the power storage device, the circuit breaker being configured to perform a breaking operation according to the abnormality diagnosis signal from the state diagnosis part.

8. The power conversion system according to claim 7, further comprising

a temperature detection part configured to detect temperature of the power storage device,

wherein the state diagnosis part is configured to correct the resistance value using a detection temperature of the temperature detection part.

9. The power conversion system according to claim 8, further comprising

an annunciation part configured to annunciate based on a diagnosis result of the state diagnosis part.

12. The power conversion system according to claim 2,

wherein the state diagnosis part is

configured to calculate at least one of a resistance value and capacitance of the power storage device as the state quantity, and

configured to diagnose a deterioration state of the power storage device based on at least one of the resistance value and the capacitance.

13. The power conversion system according to claim 12,

wherein the state diagnosis part is configured to diagnose an abnormality of the power storage device based on the resistance value.

14. The power conversion system according to claim 13,

wherein the state diagnosis part is configured to output an abnormality diagnosis signal when the state diagnosis part diagnoses as the abnormality.

15. The power conversion system according to claim 14, further comprising

a circuit breaker disposed on a DC line between the second power converter and the power storage device, the circuit breaker being configured to perform a breaking operation according to the abnormality diagnosis signal from the state diagnosis part.

16. The power conversion system according to claim 12, further comprising

a temperature detection part configured to detect temperature of the power storage device,

wherein the state diagnosis part is configured to correct the resistance value using a detection temperature of the temperature detection part.

17. The power conversion system according to claim 12, further comprising

an annunciation part configured to annunciate based on a diagnosis result of the state diagnosis part.

18. The power conversion system according to claim 1, further comprising

an annunciation part configured to annunciate based on a diagnosis result of the state diagnosis part.

10. A power converter configured to convert supplied first DC power to another second DC power having a different power value from the first DC power and to output the second DC power to a power storage device, comprising:

a control signal generation part configured to generate and output a control signal in which an AC instruction whose frequency changes within a predetermined frequency range is superposed on a DC instruction on a side of the power storage device to perform at least one of superposition of an AC voltage whose frequency changes within the predetermined frequency range on a DC voltage in the second DC power and superposition of an AC current whose frequency changes within the predetermined frequency range on a DC current in the second DC power;

a detection signal processing part configured to detect at least one of a detection value of the DC voltage superposed with the AC voltage and a detection value of the DC current superposed with the AC current; and

a state diagnosis part configured to calculate a state quantity of the power storage device by an AC impedance method based on at least one of an AC voltage component value in the detection value of the DC voltage and an AC current component value in the detection value of the DC current, and to diagnose a state of the power storage device based on the state quantity.

11. A method for diagnosing a state of a power storage device configured to store supplied second DC power, comprising:

generating and outputting a control signal in which an AC instruction whose frequency changes within a predetermined frequency range is superposed on a DC instruction on a side of the power storage device to perform at least one of superposition of an AC voltage whose frequency changes within the predetermined frequency range on a DC voltage in the second DC power and superposition of an AC current whose frequency changes within the predetermined frequency range on a DC current in the second DC power;

calculating a state quantity of the power storage device by an AC impedance method based on at least one of an AC voltage component value in a detection value of the DC voltage superposed with the AC voltage and an AC current component value in a detection value of the DC current superposed with the AC current; and

diagnosing the state of the power storage device based on the state quantity.

19. A power conversion system comprising:

a first power converter configured to convert AC power from an AC power source to first DC power;

a second power converter configured to convert the first DC power from the first power converter to another second DC power having a different power value from the first DC power; and

a power storage device configured to store the second DC power from the second power converter,

the second power converter comprising;

means for performing at least one of superposition of a predetermined AC voltage on a DC voltage in the second DC power and superposition of a predetermined AC current on a DC current in the second DC power;

means for detecting at least one of a detection value of the DC voltage superposed with the AC voltage and a detection value of the DC current superposed with the AC current; and

means for diagnosing a state of the power storage device based on at least one of the detection value of the DC voltage and the detection value of the DC current.