Battery System

Patent metadata

Field	Value
Publication number	US-2016156183-A1
Application number	US-201514937967-A
Country	US
Kind code	A1
Filing date	Nov 11, 2015
Priority date	Nov 28, 2014
Publication date	Jun 2, 2016
Grant date	—

Abstract

Provided is a battery system including: a solar panel that generates power using solar light; a power conditioning system (PCS) for solar light that converts a direct-current power which is output from the solar panel into an alternating-current power and supplies the converted power to a power system; a secondary battery; a PCS for the secondary battery that converts direct-current power charged and discharged from the secondary battery into alternating-current power and charges and discharges the converted power to and from the power system; and a smoothing unit that calculates a target value with respect to a composite value of power which is supplied to the power system by the solar panel and the secondary battery and gives a charge and discharge command to the PCS for the secondary battery in accordance with the target value. The smoothing unit includes a sample number calculation unit, a moving average calculation unit, and data of an amount of solar radiation, a moving average of an amount of power generation of the solar panel is calculated using a predetermined number of samples in the sample number calculation unit, and the number of samples is increased and decreased corresponding to an increase or decrease in the data of an amount of solar radiation.

First claim

1 . A battery system comprising:
a solar panel that generates power using solar light; a power conditioning system (PCS) for solar light that converts a direct-current power which is output from the solar panel into an alternating-current power and supplies the converted power to a power system; a secondary battery; a PCS for the secondary battery that converts direct-current power charged and discharged from the secondary battery into alternating-current power and charges and discharges the converted power to and from the power system; and a smoothing unit that calculates a target value with respect to a composite value of power which is supplied to the power system by the solar panel and the secondary battery and gives a charge and discharge command to the PCS for the secondary battery in accordance with the target value, wherein the smoothing unit includes a sample number calculation unit, a moving average calculation unit, and data of an amount of solar radiation, a moving average of an amount of power generation of the solar panel is calculated using a predetermined number of samples in the sample number calculation unit, and the number of samples is increased and decreased corresponding to an increase or decrease in the data of an amount of solar radiation.

2 . The battery system according to claim 1 , wherein the smoothing unit includes a solar radiation amount data accumulation unit that accumulates the data of an amount of solar radiation, and the number of samples is calculated using data of an amount of past solar radiation accumulated in the solar radiation amount data accumulation unit.

3 . The battery system according to claim 1 , wherein the smoothing unit includes an image capture device that captures an airspace image and a power generation amount prediction unit that acquires a positional relationship between the sun and the clouds and meteorological data including a moving speed of the clouds from the airspace image acquired in the image capture device, and predicts the amount of power generation of the solar panel from the meteorological data, and the number of samples is increased and decreased corresponding to an increase or decrease in the predicted amount of power generation of the solar panel of the power generation amount prediction unit.

4 . The battery system according to claim 1 , further comprising a solar radiation meter and a thermometer, wherein the amount of power generation of the solar panel is predicted using measurement data of the solar radiation meter and temperature data of the thermometer, and the number of samples is increased and decreased corresponding to an increase or decrease in the predicted amount of power generation of the solar panel.

5 . The battery system according to claim 1 , wherein when a capacity of the PCS for solar light is smaller than a maximum amount of power generation of the solar panel, a solar radiation meter is included therein.

6 . The battery system according to claim 1 , wherein the smoothing unit includes a solar radiation meter, and the number of samples calculated from the accumulated data of an amount of past solar radiation is corrected using the measurement data of the solar radiation meter.

7 . The battery system according to claim 1 , wherein the sample number calculation unit includes a fluctuation rate calculation device that calculates a normalized amount of solar radiation of the solar panel, calculates the number of samples by multiplying the normalized amount of solar radiation by a gain, and obtains a rate of fluctuation of a composite value, a fluctuation suppression setting unit that sets a suppression target value with respect to the rate of fluctuation, a coverage rate calculation unit that obtains a time rate in which the rate of fluctuation falls within the suppression target value, and a coverage rate setting unit that sets an attainment target value of a coverage rate, and the gain is increased and decreased corresponding to at least one of the suppression target value and the coverage rate.

8 . The battery system according to claim 1 , wherein the sample number calculation unit is switched near the maximum amount of power generation of the solar panel.

9 . The battery system according to claim 1 , wherein the smoothing unit includes both the sample number calculation unit and a fixed sample number calculation unit, one of the two is selected corresponding to a fluctuation in the amount of power generation of the solar panel, and when the variable number of samples obtained in the sample number calculation unit exceeds the fixed number of samples obtained in the fixed sample number calculation unit, the fixed number of samples is adopted.

10 . The battery system according to claim 1 , wherein when the fluctuation in the amount of power generation of the solar panel is large, the fixed number of samples is adopted.

Assignees

• Hitachi Ltd

Inventors

• Sano Yuko
• Takeda Kenji
• Shibata Toshiroh
• Nagashima Yuuji

Classifications

• H02J7/35 Primary

  with light sensitive cells · CPC title

• H02J3/381

  Dispersed generators · CPC title

• H02J2101/24

  Photovoltaics · CPC title

• H02J1/10 Primary

  Parallel operation of DC sources · CPC title

• H02J3/32

  using batteries or super capacitors with converting means · CPC title