Hitachi, Ltd.

Hitachi High-tech Corporation

Toru Kouno

Tomoharu Nakamura

Yuuichi Nagayama

Emha Bayu Miftahullatif

Katsutoshi Kondo

Tetsuharu Ohya

Koki Morikawa

Hiroya Fujimoto

Yutaka Ueda

Satoshi Miyazaki

Satoru Akiyama

Masaaki Fujimori

Kenichi Gokita

Hideyuki Shitanishi

Atsuhiko Kubo

Emhabayu Miftahullatif

Masahito Toyosaki

Ryo Wakabayashi

The objective of the present invention is to provide a technology capable of estimating a battery condition in conjunction with charging/discharging operations of a battery, without employing dedicated equipment for estimating the condition of the battery. A battery management device according to the present invention identifies a first period and a subsequent second period in a rest period after a battery finishes discharging or charging, and uses an output voltage difference in the second period to estimate the condition of the battery (see FIG.).

Battery management device, and electric power system

The purpose of the present invention is to provide a technique capable of accurately estimating SOH without relying on a calculation standard of a capacity change when obtaining the SOH. The battery state estimation device according to the present invention specifies a first period and a second period in a stop period after a battery has completed charging or discharging and refers to the relationship between an estimated value of the state of health of the battery and a measured value of the state of health, thereby estimating the measured value, said estimated value being obtained using the difference between the output voltages in the second period (refer to FIG.A).

Battery state estimation device and power system

An object of the invention is to provide a control technique capable of connecting a storage battery to a DC bus via a DC/DC converter and controlling charging and discharging of the storage battery by the DC/DC converter. A DC grid system according to the invention calculates a voltage command value of a DC bus using a present voltage of a storage battery and a target voltage of the storage battery, and provides the voltage command value as a command value for each of an AC/DC converter and a DC/DC converter (see FIG.).

DC grid system, control device, and control method

An object of the present invention is to provide a battery state estimation device capable of accurately estimating a deterioration state of an entire battery system in consideration of an SOH distribution of battery cells. The battery state estimation device according to the present invention estimates an SOH of a battery cell by using a correspondence between a time derivative of an output voltage during a pause period of the battery cell and a battery temperature, and estimates a deterioration state of an entire battery system by using the SOHs of a plurality of battery cells (see FIG.).

Battery state estimation device

Provided is a battery estimation system comprising a processor and a storage device coupled to the processor. The storage device stores accelerated test data obtained by measuring change in degree of deterioration of a rechargeable battery cell at a predetermined temperature. The processor calculates a relationship between the temperature and the magnitude of an activation energy of the rechargeable battery cell on the basis of the accelerated test data, calculates a temperature as a maximum temperature on the basis of the relationship between the temperature and the magnitude of the activation energy of the rechargeable battery cell, the calculated temperature being a temperature at which the magnitude of the activation energy changes from decreasing to increasing in response to increase in the temperature, and determines a temperature equal to or less than the maximum temperature as a temperature to be used in an accelerated test.

Battery estimation system, battery estimation method, and storage medium

A diagnosis system including: a power collection unit configured to couple a plurality of photovoltaic cell arrays, each including photovoltaic cells, in parallel; a control unit; and a monitoring unit, the monitoring unit being configured to: estimate a solar radiation amount and an operating temperature of the photovoltaic cell arrays based on the current value measured by a first ammeter in the control unit and the voltage value measured by the first voltmeter in the control unit by using an expression expressing a relationship between the solar radiation amount, the operating temperature, and a number of photovoltaic cells, and an output current; correct the estimated values so as to match the current values measured by second ammeters in the power collection unit by using the expression; and calculate a theoretical current value of each of the photovoltaic cell arrays based on the corrected values by using the expression.

Diagnosis system and diagnosis method for photovoltaic power generation system

A monitor device in a solar power generation system extracts a first time band indicating a minimum amount of solar radiation and a second time band indicating a maximum amount of solar radiation in a day, and calculates, using a ratio of operation and short-circuit currents in a solar battery array, an expected electric power value of a solar battery string to be inspected in each of the first and second time bands. From measurement electric power values of the solar battery string to be inspected in the time bands, the expected electric power value of the first time band, and the expected electric power value of the second time band, first and second electric power losses in the first and second time bands are calculated, and a failure in the solar battery string to be inspected is detected based on the first and second electric power losses.

Solar power generation system and failure diagnosis method therefor

A failure diagnosis system is configured to calculate an estimated irradiation on a first photovoltaic string and an estimated operating temperature of the first photovoltaic string based on a short-circuit current and an open-circuit voltage on a current-voltage characteristic of the first photovoltaic string, and the array output voltage value and the array output current value measured by an array measurement apparatus. The failure diagnosis system is configured to calculate an estimated current value of the first photovoltaic string based on the estimated irradiation, the estimated operating temperature, and the current-voltage characteristic. The failure diagnosis system is configured to diagnose degradation of the first photovoltaic string by comparing the measured current value of the first photovoltaic string and the estimated current value.

Failure diagnosis method and failure diagnosis system for photovoltaic system

The diagnostic method for a photovoltaic power system includes: a step of storing measured values of voltage and current outputted by a photovoltaic cell array, and identifying a first time period and a second time period with a lower solar radiation amount than in the first time period; a step of calculating the number of faulty photovoltaic cells on the basis of the measured values in the first time period; a step of calculating the number of faulty photovoltaic cells on the basis of the measured values in the second time period; and a step of comparing the number of faulty photovoltaic cells as calculated for the first time period, and the number of faulty photovoltaic cells as calculated for the second time period, and identifying a series resistance of the photovoltaic cells and a value indicating a degree of loss resulting from a fault in the photovoltaic cells.

Diagnostic method for solar power system and monitoring device

A power generating system comprising: a plurality of power generating units coupled in parallel; a power collecting device for collecting electric power output from the plurality of power generating units; and wirings for coupling the plurality of power generating units and the power collecting device. A ratio of a conductor diameter to a predetermined length of each of the wirings is defined as a reference ratio. A value obtained by multiplying the reference ratio, a number of the wirings, and a loss generated by a specific wiring together is subtracted from a value obtained by multiplying a predetermined number of wirings for adjustment by a ratio of a conductor diameter to a length of the specific wiring. A total of the ratios of the conductor diameters to the lengths of the predetermined number of the wirings for adjustment is determined as a value less than the subtracted value.

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Tokyo, Japan

Toru Kouno