JP5038258B2 - Remaining capacity estimation method and remaining capacity estimation apparatus - Google Patents

Description

  The present invention relates to a remaining capacity estimation method and a remaining capacity estimation apparatus.

  Conventionally, a self-supporting power source composed of a storage battery and a solar cell has been used as a power source for a load installed in a place where it is difficult to secure a power infrastructure. In a self-supporting power source, power generated by solar cells is supplied to the load during daytime when there is a lot of sunlight, and the storage battery is charged with surplus power. Necessary power will be provided.

  Here, when operating a self-supporting power source as a power source for a load, it is important to estimate a remaining capacity (SOC: State of charge) of the storage battery.

  That is, if the amount of sunshine is sufficient and surplus power continues to be supplied from the solar battery to the storage battery, the storage battery is fully charged and then overcharged, and the deterioration of the storage battery proceeds. In addition, if the state of non-sunshine continues and the discharge from the storage battery to the load continues, the remaining capacity of the storage battery decreases in order to continue supplying the power consumption required by the load, eventually resulting in overdischarge, Deterioration progresses.

  Therefore, a method is known in which the remaining capacity of the storage battery is estimated by measuring the charge / discharge current of the storage battery and integrating it, or measuring the steady voltage of the storage battery.

  In addition, a method for estimating the remaining capacity of a nickel metal hydride storage battery mounted as a battery in an electric vehicle or a hybrid vehicle using a measured concentration of nickel oxyhydroxide is known (see, for example, Non-Patent Document 1).

  There is also known a method for estimating the remaining capacity of a nickel-metal hydride storage battery mounted as a battery in an electric vehicle or a hybrid vehicle by using an ANN (Artificial neural network) method (see, for example, Non-Patent Document 2). Specifically, a specific discharge current category is set, and in the set category, the remaining capacity of the storage battery in various combinations of discharge current and temperature is experimentally measured, and the measured experimental data is used as learning data. The relational expression for estimating the remaining capacity from the discharge current and temperature is calculated by the neural network.

  Moreover, the remaining capacity of the nickel-metal hydride storage battery for general equipment is estimated by specifying the impedance inside the storage battery by system identification using an equivalent circuit model created in advance and obtaining the relational expression between the specified impedance and the remaining capacity. The method is also known (for example, refer nonpatent literature 3).

“State of Charge Estimator for NiMH Batteries”, Proceedings of 41st IEEE Conf., 2002 “Neural Net-work-Based Residual Capacity Indicator for Nickel-Metal Hydride Batteries in Electric Vehicles”, IEEE Transaction on vehicular technology, Vol. 54, No.5, pp.1705- 1712, 2005 "Remaining capacity diagnosis of nickel metal hydride and nickel cadmium batteries using system identification" IEEJ Journal D, 126, 3, pp.285-291, 2006

  Here, when the storage battery constituting the self-supporting power source is a nickel metal hydride storage battery or the like, if the surplus power supplied from the solar battery is small and the charging current is very small, the charging current is not charged to the storage battery, and the inside of the battery It turns into heat. Further, the storage battery is deteriorated by heat generated by the inflow of a minute charging current. For this reason, in a self-supporting power source using a nickel-metal hydride storage battery as a storage battery, a measure for discarding a minute charging current may be taken to protect the storage battery.

  In addition, when the amount of sunshine changes drastically due to cloudy or shaded effects, the amount of current generated by the solar cell varies. Furthermore, regardless of the type of storage battery, even if the charging current is the same, the power stored in the storage battery varies depending on the temperature.

  For this reason, the remaining capacity of the storage battery estimated using the charge / discharge current is not necessarily highly accurate.

  In addition, in the case of a storage battery having a relatively large voltage difference between a full charge and a complete discharge such as a lead storage battery of “3.0 V to 2.0 V”, the remaining capacity can be easily estimated by the voltage. In the case of a storage battery such as a nickel metal hydride storage battery having a small voltage difference of “1.5 V to 1.0 V” between full charge and complete discharge, it is difficult to easily estimate the remaining capacity based on the voltage. Furthermore, as described above, regardless of the type of the storage battery, a bias of the voltage stored in the storage battery occurs due to the temperature.

  For this reason, the remaining capacity of the storage battery estimated using the voltage is not necessarily highly accurate.

  Moreover, in order to estimate the remaining capacity of the nickel-metal hydride storage battery mounted as a battery from the measured concentration of nickel oxyhydroxide, advanced calculation processing is required, and it takes a device (for example, a microcomputer) that estimates the remaining capacity. The cost increases and the power consumption required by the device also increases. For this reason, the method of estimating the remaining capacity from the measured concentration of nickel oxyhydroxide is difficult to apply to a self-supporting power source.

  Moreover, the method for estimating the remaining capacity of the nickel-metal hydride storage battery by the ANN method is a parameter setting based on a premise of a steep current change pattern in a battery mounted on an electric vehicle or a hybrid vehicle. For this reason, even if the conventional method of estimating the remaining capacity of the nickel-metal hydride storage battery by the ANN method is used, the estimation of the remaining capacity of the nickel-metal hydride storage battery constituting the self-supporting power source should be performed with high accuracy in consideration of the minute current. I can't.

  In addition, in the method of estimating the remaining capacity of the nickel metal hydride storage battery using the equivalent circuit model, the estimation accuracy of the remaining capacity depends on the modeling precision of the equivalent circuit model, and further, the equivalent circuit model Since correction is required, the remaining capacity cannot be estimated accurately.

  As described above, the above-described conventional technique has a problem that the remaining capacity of the storage battery in the self-supporting power source cannot be accurately estimated.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and a remaining capacity estimation method and a remaining capacity estimation apparatus capable of accurately estimating the remaining capacity of a storage battery in a self-supporting power source. The purpose is to provide.

In order to solve the above-described problems and achieve the object, this method is a self-contained power source composed of a solar battery that generates power by sunlight and a storage battery that charges and discharges using the power generated by the solar battery. The remaining capacity estimating method for estimating the remaining capacity of the storage battery , comprising a measured value in an environment corresponding to a stable period in which the amount of change in charge / discharge current for the storage battery is within a predetermined range over a predetermined time Data, and using the storage battery voltage and the remaining capacity variation patterns measured in advance for each of a plurality of combinations set so that the temperature of the storage battery and the charge / discharge current for the storage battery are constant, as teacher data From the charging / discharging current, the temperature of the storage battery, and the voltage of the storage battery, the remaining capacity output function that outputs the remaining capacity And determining parameter calculation step of calculating the remaining capacity output parameters for the after starting operation of the self-supporting power source, a determination step of determining whether or not a between front Symbol plateau, the stable period by said determining step If it is determined, the charge and discharge current of the battery, the measured value of temperature and voltage, by using the remaining capacity output function determined by the parameter calculating the remaining capacity output parameter calculated by step and, A remaining capacity calculation step of calculating a remaining capacity of the storage battery in the stable period; and a remaining current calculated by the remaining capacity calculation step is close to a full charge of the storage battery, a charging current from the solar battery And a control step for performing control to stop the operation.

In addition, this device has a remaining capacity for estimating the remaining capacity of the storage battery in a self-supporting power source configured by a solar battery that generates power by sunlight and a storage battery that performs charging and discharging using the power generated by the solar battery. An estimation device, which is data consisting of measured values in an environment corresponding to a stable period in which the amount of change in charge / discharge current with respect to the storage battery is within a predetermined range over a predetermined time, and the temperature of the storage battery and the storage battery The charge / discharge current, the temperature of the storage battery, by using each of the fluctuation patterns of the voltage and remaining capacity of the storage battery measured in advance for each of a plurality of combinations set so that the charge / discharge current for the battery is constant And a remaining capacity output parameter for determining a remaining capacity output function using the voltage of the storage battery as an input and a remaining capacity as an output. A parameter calculating means for calculating a, after starting operation of the free-standing power, judging means for judging whether or not a between front Symbol plateau, when it is determined that the stable period by the determining means, the storage battery By using the measured values of the charge / discharge current, temperature and voltage of the battery and the remaining capacity output function determined by the remaining capacity output parameter calculated by the parameter calculating means, the remaining capacity of the storage battery in the stable period is obtained. A remaining capacity calculating means for calculating a capacity; and a control means for controlling to stop the charging current from the solar battery when the remaining capacity calculated by the remaining capacity calculating means is near the full charge of the storage battery; it may be a requirement that with a.

  According to the disclosed method and apparatus, the remaining capacity can be calculated from the measured value related to the storage battery in the stable period by the parameter calculated using the teacher data consisting of the actually measured value in the environment corresponding to the stable period, It becomes possible to accurately estimate the remaining capacity of the storage battery constituting the self-supporting power source.

  Exemplary embodiments of a remaining capacity estimation method and a remaining capacity estimation apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. In the following description, the remaining capacity estimation method according to the present invention is executed in a self-supporting power source system including a self-supporting power source composed of a solar battery and a storage battery and a load operated by power supplied from the self-supporting power source. A case where a control device is installed will be described as an example.

[Configuration of self-supporting power supply system in this embodiment]
First, the configuration of the self-supporting power supply system in the present embodiment will be described with reference to FIG. FIG. 1 is a diagram for explaining a configuration of a self-supporting power supply system according to the present embodiment.

  As shown in FIG. 1, the self-supporting power supply system in this embodiment includes a PV panel 1, a nickel metal hydride storage battery 2, a controller 3, a load 4, a control device 5, a shunt resistor 6, and a battery disconnection switch 7. And a load separation switch 8. In FIG. 1, a solid line indicates a power line, and a dotted line indicates a correspondence relationship of control by the control device 5.

  The PV panel 1 is a device that performs solar power generation (Photo Voltaic), and corresponds to a “solar cell” recited in the claims.

  The nickel-metal hydride storage battery 2 is a battery module composed of a plurality of battery cells. For example, as shown in FIG. 2, the nickel-metal hydride storage battery 2 in this embodiment has ten nominally 95 Ah battery cells connected in series. Further, the battery pack includes a temperature sensor attached to the battery cell, a connector for taking out the temperature sensor and the power line, a cooling fan, and a storage box. In addition, FIG. 2 is a figure for demonstrating the nickel hydride storage battery used in a present Example.

  A characteristic of general nickel metal hydride storage batteries is high temperature sensitivity. That is, since the output voltage of the nickel metal hydride storage battery varies depending on temperature fluctuation, if the battery cell temperature varies during charging, the charging capacity also varies, and the operation of each cell during charging / discharging becomes uneven. For this reason, the nickel-metal hydride storage battery 2 composed of a plurality of battery cells has a disadvantage that the deterioration is accelerated only by a specific battery cell, and the deterioration is accelerated as a whole.

  Here, the power generation scale of the PV panel 1 and the number of battery cells constituting the nickel-metal hydride storage battery 2 (that is, the battery mounting capacity of the nickel-metal hydride storage battery 2) are the power consumption of the load 4 and the PV panel 1 described later. It is adjusted by the manager of the self-supporting power supply system based on the information of the non-sunshine period set from the weather history of the installed environment.

  The controller 3 detects the maximum output point (MPP: Maximum Power Point) that maximizes the output power of the PV panel 1 and extracts the maximum power from the PV panel 1, and the load 4 described later on the MPPT (Maximum Power Point Tracker). It is comprised from the DC / DC converter which produces | generates two types of voltages, the voltage to supply and the battery charging voltage to the nickel metal hydride storage battery 2. FIG.

  The load 4 is a device that operates with the power supplied from the PV panel 1 or the nickel metal hydride storage battery 2. For example, the load 4 is continuously monitored and driven by consuming power or periodically (for example, every one minute). ) A device such as a wireless transmitter that consumes power to drive.

  In the self-supporting power source composed of the PV panel 1, the nickel-metal hydride storage battery 2, and the controller 3, when the sun is shining during the day, the PV panel 1 generates power. Detected and maximum power is taken out. Further, the controller 3 generates a voltage to be supplied to the load 4, and the generated power is supplied to the load 4, and a battery charging voltage is generated from surplus power and then supplied to the nickel metal hydride storage battery 2 for charging. Is done. In addition, during nighttime and periods when sunlight is not sufficient, power supply to the load 4 is provided by discharge from the nickel metal hydride storage battery 2.

  The control device 5 monitors the state of the controller 3 by acquiring the voltage / current output from the controller 3 to the load 4, and based on the acquired voltage / current value, turns on / off the load separation switch 8. By controlling, the load 4 is electrically protected.

  For example, when the current value output to the load 4 exceeds a specified value, the control device 5 determines that a failure has occurred in the controller 3 and turns off the load disconnection switch 8 to turn off the load 4. Protect electrically. The control device 5 turns on the load separation switch 8 when the voltage / current output from the controller 3 to the load 4 becomes normal.

  Moreover, the control apparatus 5 monitors the state of the nickel-metal hydride storage battery 2 and controls the battery disconnection switch 7 to be turned on / off, thereby electrically protecting the nickel-metal hydride storage battery 2.

  Here, the control device 5 installed in the self-supporting power supply system in the present embodiment can accurately estimate the remaining capacity of the nickel metal hydride storage battery 2 in order to monitor the state of the nickel metal hydride storage battery 2. Has the main characteristics. Hereinafter, this main feature will be described with reference to FIGS. 3 to 6 together with FIGS. 1 and 2. FIG. 3 is a diagram for explaining an example of teacher data, FIG. 4 is a diagram for explaining a combination of teacher data, and FIG. 5 is a diagram for explaining a model used in the parameter calculation unit. FIG.

  As shown in FIG. 1, the control device 5 includes a parameter calculation unit 51, a parameter storage unit 52, a remaining capacity calculation unit 53, a deterioration degree calculation unit 54, and a discharge / charge control unit 55. Here, the control device 5 acquires the temperature of the nickel hydride storage battery 2 from the temperature sensor described in FIG. 2, and further acquires the voltage of the nickel hydride storage battery 2. In addition, the control device 5 acquires a charge / discharge current for the nickel-metal hydride storage battery 2 by measuring a voltage generated at both ends of the shunt resistor 6.

  In the following, the temperature of the nickel metal hydride storage battery 2 is “battery temperature” or “temperature”, the voltage of the nickel metal hydride storage battery 2 is “battery voltage” or “voltage”, and the charge / discharge current for the nickel metal hydride storage battery 2 is “charge / discharge current”. May be abbreviated as “”.

  The parameter calculation unit 51 includes a battery voltage and a remaining capacity variation pattern for each of the nickel-metal hydride storage batteries 2 having different degrees of deterioration measured in advance for each of a plurality of combinations set so as to make the battery temperature and charge / discharge current constant. The remaining capacity output parameters for determining the remaining capacity output function using the charge / discharge current, battery temperature, and battery voltage as inputs and the remaining capacity as outputs by using each of them as variation data (variation patterns for different degrees of deterioration) Is calculated.

  Further, the parameter calculation unit 51 uses each deterioration degree variation pattern as teacher data, thereby determining a deterioration degree output function that inputs the charge / discharge current, the battery temperature, and the battery voltage and outputs the deterioration degree. A parameter for output of the deterioration level is also calculated. The remaining capacity output parameter and the degradation level output parameter are used as parameters for estimating the remaining capacity and the degradation level based on the remaining capacity by an ANN (Artificial neural network) method.

  Here, the parameter calculation unit 51 performs processing using two types of teacher data described below.

  The first teacher data is a fluctuation pattern (deterioration degree fluctuation pattern) when a constant discharge current flows out from each of the nickel metal hydride storage batteries 2 having different deterioration degrees.

  In measuring the first teacher data, first, a plurality of nickel-metal hydride storage batteries 2 having a known degree of deterioration are prepared.

  And the prepared nickel-metal hydride storage battery 2 from which a deterioration degree differs is made into a full charge state, respectively, and the storage battery used as the full charge state is installed in a thermostat, and it maintains at predetermined | prescribed environmental temperature. After that, each of the nickel metal hydride storage batteries 2 whose temperature is in a steady state is swept with a predetermined constant current, and the fluctuation pattern of the remaining capacity and the battery voltage is measured.

  Here, the value obtained by dividing the value obtained by multiplying the sweeping time (hour) by the sweep current (equivalent to the discharge current during operation of the self-supporting power source) by the nominal capacity of the nickel metal hydride storage battery 2 is indicated as a percentage. The value obtained by subtracting the discharge amount from 100 is the remaining capacity.

  The second teacher data is a fluctuation pattern (deterioration degree fluctuation pattern) when a constant charging current is introduced from each of the nickel hydride storage batteries 2 having different deterioration degrees.

  In measuring the second teacher data, first, a plurality of nickel-metal hydride storage batteries 2 with known degrees of deterioration are prepared in the same manner as the first teacher data.

  And each prepared nickel-metal hydride storage battery 2 from which a deterioration degree differs is made into an empty state. Specifically, the nickel metal hydride storage battery 2 is discharged to the lowest allowable voltage (allowable minimum voltage). After that, each of the nickel metal hydride storage batteries 2 discharged to an allowable minimum voltage is installed in a thermostat and maintained at a predetermined environmental temperature, and each of the nickel metal hydride storage batteries 2 whose temperature is in a steady state is continued at a predetermined constant current. And charge, and measure the fluctuation pattern of the remaining capacity and battery voltage.

  Here, the value obtained by multiplying the value obtained by multiplying the charging time (hour) by the charging current by the nominal capacity of the nickel metal hydride storage battery 2 is the remaining capacity.

  For example, in the environment of 15 ° C., the teacher data when the nickel hydride storage battery 2 without deterioration (new article) is discharged and charged at 1 A is measured as a charge / discharge curve as shown in FIG. In FIG. 3, a discharge curve (the horizontal axis is the discharge amount) when the battery voltage of 10 V is set as the allowable minimum voltage is shown as the first teacher data at the time of discharge. As the teacher data, a charging curve (remaining capacity on the horizontal axis) when the charging amount of 95 Ah is 100% is shown.

  In this way, the deterioration degree fluctuation pattern (remaining capacity-battery voltage) for each of a plurality of combinations is measured. If the number of teacher data is small, the accuracy of the estimated value by the ANN method will be poor, and if it is too large, the calculation will be too complicated when the calculation is performed by the ANN method. Set by the administrator of the self-supporting power supply system.

  For example, if the battery capacity due to deterioration is determined by 30% capacity reduction, “No deterioration (new)”, “Deterioration degree 15% (15% capacity reduction)”, “Deterioration degree 30% ( Three types of nickel metal hydride storage batteries 2 of “30% capacity reduction” are prepared. In addition, for example, when a self-supporting power supply is installed in an area where the temperature fluctuates between “0 ° C. and 40 ° C.” throughout the year, there are three types of deterioration that are in a fully charged state or discharged to an allowable minimum voltage. The nickel-metal hydride storage batteries 2 having different degrees are maintained at “0 ° C.” assuming winter, “20 ° C.” assuming normal temperature such as spring and autumn, and “40 ° C.” assuming the highest temperature in summer. Furthermore, considering the power consumption of the load 4 that is operated by the self-supporting power source, the discharge current is set to three types of “1A”, “2A”, and “3A”, the power generation scale of the PV panel 1 and the capacity of the nickel metal hydride storage battery 2 In consideration of the above, the charging current is set to two types, “7A” and “10A”.

  Then, in the case of “no deterioration”, the administrator of the self-supporting power supply system measures the deterioration degree fluctuation pattern of case 1 to case 15 for each of the 15 types of combinations as shown in FIG. In the case of “deterioration degree of 15%”, as shown in FIG. 4B, the deterioration degree variation pattern of case 16 to case 30 is measured for each of the 15 types of combinations. As shown in (C), the deterioration degree fluctuation pattern of case 31 to case 45 is measured for every 15 types of combinations.

Here, the parameter calculation unit 51 calculates the parameters based on the neural network model shown in FIG. That is, as shown in FIG. 5, the model of the ANN method used in this example is “P ₁ : charge / discharge current”, “P ₂ : (battery) temperature”, “P ₃ : (battery) voltage”. It is a model that outputs “R ₁ : remaining capacity (SOC)” and “R ₂ : degradation degree” through an intermediate layer consisting of five units “Q _{1 to} Q ₅ ” as an input. is there. Here, in “P ₁ : charge / discharge current”, the discharge current is a positive value and the charge current is a negative value. In this embodiment, the case where the number of units in the intermediate layer is five will be described. However, the present invention is not limited to this, and an arbitrary number of units can be set as long as the calculation result converges. The

  First, in the model shown in FIG. 5, a sigmoid function “f (x)” expressed by the following equation (1) is used.

In the model shown in FIG. 5, “f (x)” having “P _{1 to} P ₃ ” as an input (x) and “Q _{1 to} Q ₅ ” as an output is represented by the following equation (2): It is represented by

Here, “V _nj ” in Equation (2) is a weighting coefficient, and “B _j ” is a bias. In other words, the function with the input layer “P _{1 to} P ₃ ” as input and the intermediate layer “Q ₁ ” as output is the weighting coefficient from P ₁ to Q ₁ is “V ₁₁ ”, and the weight from P ₂ to Q ₁ Since the coefficient is “V ₂₁ ”, the weighting coefficient from P ₃ to Q ₁ is “V ₃₁ ”, and the bias to Q ₁ is “B ₁ ”, as shown in FIG. ₁ = f (P ₁ * V ₁₁ + P ₂ * V ₂₁ + P ₃ * V ₃₁ + B ₁₎ . Similarly, the input layer “P _{1 to} P ₃ ” is input and the intermediate layer “Q ₂ ” is As shown in FIG. 5, the output function is “Q ₂ = f (P ₁ * V ₁₂ + P ₂ * V ₂₂ + P ₃ * V ₃₂ + B ₂ )” according to the equation (2).

In the model shown in FIG. 5, “f (x)” having “Q _{1 to} Q ₅ ” as input (x) and “R ₁ , R ₂ ” as output is represented by the following equation (3): It is represented by

Here, “W _mk ” in Equation (3) is a weighting coefficient, and “C _k ” is a bias. That is, the function having the intermediate layer “Q _{1 to} Q ₅ ” as an input and the output layer “R ₁ ” as an output is expressed by “R ₁ = f (Q ₁ * W ₁₁ + Q ₂ * W ₂₁ + Q ₃ * w ₃₁ + Q ₄ * W ₄₁ + Q ₅ * W ₅₁ + C ₁ ) ”. Similarly, a function having the intermediate layer “Q _{1 to} Q ₅ ” as an input and the output layer “R ₂ ” as an output is expressed as “R ₂ = f (Q ₁ * W ₁₂ + Q ₂ * W ₂₂ + Q ₃ * W ₃₂ + Q ₄ * W ₄₂ + Q ₅ * W ₅₂ + C ₂ ) ”.

That is, the parameter calculation unit 51 substitutes 45 types of deterioration degree variation patterns into the above-described formula as teacher data, and 15 weighting coefficients ““ V ₁₁ ”to“ V ₃₅ ”when converged by the ANN method and Five weighting factors “W ₁₁ ” to “W ₅₁ ” and “6 biases“ B ₁ ”to“ B ₅ ”and“ C ₁ ”” are calculated as remaining capacity output parameters.

Also, the parameter calculation unit 51 substitutes 45 types of deterioration degree variation patterns into the above-described formula as teacher data, and 15 weighting coefficients ““ V ₁₁ ”to“ V ₃₅ ”when converged by the ANN method and Five weighting coefficients “W ₁₂ ” to “W ₅₂ ” and “6 biases“ B ₁ ”to“ B ₅ ”and“ C ₂ ”” are calculated as deterioration degree output parameters. The remaining capacity output parameter and the degradation level output parameter share “V ₁₁ ” to “V ₃₅ ” and “B ₁ ” to “B ₅ ”.

  Returning to FIG. 1, the parameter storage unit 52 stores the remaining capacity output parameter and the deterioration level output parameter calculated by the parameter calculation unit 51.

The remaining capacity calculation unit 53 performs charge / discharge current, battery temperature, and battery in a stable period in which the change amount of the charge / discharge current with respect to the nickel-metal hydride storage battery 2 is within a predetermined range over a predetermined time after the operation of the self-supporting power source is started. By using the measured voltage value and the remaining capacity output function (R ₁ described above) determined by the remaining capacity output parameter stored in the parameter storage unit 52, the remaining capacity in the stable period of the nickel metal hydride storage battery 2 is calculated. .

Further, the deterioration degree calculation unit 54 is determined by measured values of the charge / discharge current, the battery temperature, and the battery voltage, and the deterioration degree output parameters stored in the parameter storage unit 52 in the stable period after the start of operation of the self-supporting power source. By using the deterioration degree output function (R ₂ described above), the degree of deterioration based on the remaining capacity of the nickel metal hydride storage battery 2 in the stable period is calculated.

  For example, the control device 5 continuously acquires the charge / discharge current for the nickel metal hydride storage battery 2 from the shunt resistor 6 after starting the operation of the self-supporting power source, and the fluctuation value of the charge current or the discharge current is the charge current or the discharge current. If the period that is within the range of 1/10 and the fluctuation value is within the range of 1/10 of the charging current or discharging current continues for 1 minute or more, it is determined as the stable period and the remaining capacity is calculated. The processing of the unit 53 and the deterioration degree calculation unit 54 is started.

  Here, the remaining capacity calculation unit 53 and the deterioration level calculation unit 54 respectively calculate the remaining capacity and the deterioration level at a plurality of times from the charge / discharge current, the battery temperature, and the battery voltage measured at a plurality of times in the stable period. calculate. The accuracy of the calculation result is improved by calculating an average value and a predicted value of the remaining capacity and the degree of deterioration using the least square method over time from the calculated plurality of remaining capacity and the degree of deterioration. Note that the number of calculations of the remaining capacity and the degree of deterioration is set to a predetermined number by the administrator of the self-supporting power system. In the following, a case where an average value (average remaining capacity and average deterioration degree) is calculated from a plurality of calculated remaining capacities and deterioration degrees will be described.

  Here, the stable period is roughly divided into the following three periods.

  The first period is at night. At night when sunlight is not radiated, the temperature is relatively stable, and the PV panel 1 is not generated, and a stable environment is discharged from the nickel hydride storage battery 2 to the load 4 at a constant current. Therefore, as long as the conditions for the stable period described above are met, for example, charge / discharge current, battery temperature, and battery voltage are measured several times every hour from 9:00 pm to 3:00 am on the next day, Calculate capacity and degree of degradation. In particular, the first period is considered to be a time suitable for estimating the remaining capacity and the degree of deterioration with high accuracy.

  The second period is the daytime when the amount of sunshine is sufficient. In the daytime when there is a sufficient amount of sunshine, a sufficient current for driving the load 4 flows from the PV panel 1, so that the nickel metal hydride storage battery 2 is charged with a stable charging current from the PV panel 1. Therefore, as long as the conditions of the stable period described above are satisfied, for example, every 10 minutes from 11:00 am to 3:00 pm, the charge / discharge current, the battery temperature, and the battery voltage are measured a plurality of times to obtain a plurality of remaining capacities. And the degree of deterioration is calculated. In particular, the second period is considered to be a suitable time for calculating the estimated value of the remaining capacity and detecting full charge, so it is desirable to shorten the measurement interval.

  The third period is the daytime when the amount of sunshine is unstable due to repeated sunny and cloudy days. In the daytime when the amount of sunshine is unstable, the time when the PV panel 1 can supply sufficient power to the load 4 and the time when the PV panel 1 cannot supply power are repeated. The current outflow is repeated. For this reason, every time the stable period is reached, the charge / discharge current, the battery temperature, and the battery voltage are measured a plurality of times at shorter measurement intervals (for example, every minute) to calculate a plurality of remaining capacities and deterioration levels.

  In this manner, the remaining capacity calculation unit 53 and the deterioration level calculation unit 54 calculate the remaining capacity and the deterioration level at a plurality of points in time during the stable period, and calculate the average remaining capacity and the average deterioration level.

  Based on the calculation results of the remaining capacity calculation unit 53 and the deterioration level calculation unit 54, the charge / discharge control unit 55 opens and closes (on / off) the battery disconnect switch 7 in order to electrically protect the nickel metal hydride storage battery 2. Take control.

  That is, the charge / discharge control unit 55 turns off the battery disconnection switch 7 when the average deterioration degree calculated by the deterioration degree calculation part 54 is lower than the set value for storage battery replacement (for example, 30%). A battery replacement notification lamp (not shown) provided in the device 5 is turned on. Further, when the storage battery is replaced and, for example, a reset button (not shown) provided in the control device 5 is pressed by the administrator, the charge / discharge control unit 55 turns on the battery disconnect switch 7.

  In addition, when the average remaining capacity calculated by the deterioration degree calculating unit 54 is close to the full charge of the nickel metal hydride storage battery 2, the charge / discharge control unit 55 turns off the battery disconnect switch 7 to prevent overcharge. The charging current from the PV panel 1 is stopped. After that, when the output power of the PV panel 1 acquired from the controller 3 is lower than the power consumption of the load 4, the charge / discharge control unit 55 sets the battery disconnect switch 7 to discharge the load 4. turn on.

  Further, the charge / discharge control unit 55 turns off the battery disconnection switch 7 when the average remaining capacity calculated by the deterioration degree calculation unit 54 falls below the set threshold value. Here, the set threshold value is a value that is set as a possibility that the nickel-metal hydride storage battery 2 may be in an overdischarged state when discharging to the load 4 is continued. In addition, after turning off the battery disconnection switch 7, when the output power of the PV panel 1 acquired from the controller 3 becomes equal to or higher than the power consumption of the load 4, the charge / discharge control unit 55 determines that charging is possible. Then, the battery disconnecting switch 7 is turned on.

  Here, when it falls below the set threshold value, the charge / discharge control unit 55 does not turn off the battery disconnecting switch 7 to prevent overdischarge, but the charge / discharge control unit 55 reduces the processing execution frequency of the load 4 to thereby reduce the discharge amount. May be reduced.

[Procedure of processing by the control device in this embodiment]
Next, the process of the control apparatus 5 in a present Example is demonstrated using FIG. 6 and FIG. FIG. 6 is a flowchart for explaining the parameter calculation processing of the control device in this embodiment, and FIG. 7 is a flowchart for explaining the processing after the autonomous power supply operation of the control device in this embodiment is started. .

[Procedure for Parameter Calculation Processing by Control Device in Present Example]
As shown in FIG. 6, when the control data in the present embodiment is input with teacher data (45 deterioration degree variation patterns) as shown in FIG. 4 (Yes in step S601), the parameter calculation unit 51 By substituting the teacher data into the relational expression based on the model shown in FIG. 5, the remaining capacity output parameter for determining the remaining capacity output function and the deterioration level output parameter for determining the deterioration level output function are calculated (step) S602).

  Then, the parameter calculation unit 51 stores the calculated remaining capacity output parameter and deterioration level output parameter in the parameter storage unit 52 (step S603), and ends the process.

[Procedure for Parameter Calculation Processing by Control Device in Present Example]
As shown in FIG. 7, when the operation of the self-supporting power supply is started (Yes in Step S701), the control device 5 in the present embodiment starts measuring the charge / discharge current using the shunt resistor 6 (Step S702). Then, it is determined whether or not the amount of change in the charge / discharge current with respect to the nickel metal hydride storage battery 2 has reached a stable period within a predetermined range over a predetermined time (step S703).

  Here, when it is not determined as the stable period (No at Step S703), the control device 5 continues to monitor the measurement result of the charge / discharge current.

  On the other hand, when it is determined as the stable period (Yes in step S703), the control device 5 measures the charge / discharge current, the (battery) temperature, and the (battery) voltage at regular intervals, and determines the remaining capacity calculation unit 53 and the deterioration degree. The calculation unit 54 calculates the remaining capacity and the deterioration level at a plurality of points in time using the remaining capacity output parameter and the deterioration level output parameter stored in the parameter storage unit 52 (step S704). Note that the number of calculations of the remaining capacity and the degree of deterioration is set to a predetermined number by the administrator of the self-supporting power system.

  Then, each of the remaining capacity calculation unit 53 and the deterioration degree calculation unit 54 calculates an average remaining capacity and an average deterioration degree from the remaining capacity and the deterioration degree at a plurality of times (step S705).

  Here, the charge / discharge control unit 55 turns off the battery disconnection switch 7 (step S709) when the average deterioration degree is lower than the set value for replacement of the storage battery (Yes in step S706).

  On the other hand, when the average deterioration degree is equal to or greater than the set value for replacement of the storage battery (No at Step S706), the charge / discharge control unit 55 determines whether or not the average remaining capacity is close to full charge (Step S707).

  When the average remaining capacity is close to full charge (Yes at Step S707), the charge / discharge control unit 55 turns off the battery disconnection switch 7 (Step S710).

  On the other hand, when the average remaining capacity is not near the full charge (No at Step S707), the charge / discharge control unit 55 determines whether or not the average remaining capacity is below the set threshold (Step S708).

  When the average remaining capacity falls below the set threshold value (Yes at Step S708), the charge / discharge control unit 55 turns off the battery disconnection switch 7 (Step S711).

  On the other hand, when the average remaining capacity is equal to or greater than the set threshold (No at Step S708), the control device 5 returns to Step S703 and continues to monitor the measurement result of the charge / discharge current.

  Moreover, when the charge / discharge control part 55 detects that the reset button with which the control apparatus 5 was equipped was pressed by the administrator after the process of step S709, it determines with the storage battery having been replaced | exchanged (step S712 affirmation), and battery separation. The switch 7 is turned on (step S715), and the process returns to step S703 to continue monitoring the charge / discharge current measurement result.

  Moreover, after the process of step S710, when the output power of the PV panel 1 acquired from the controller 3 falls below the power consumption of the load 4 (Yes in step S713), the charge / discharge control unit 55 turns on the battery disconnect switch 7 ( Step S716), the process returns to step S703, and the measurement result of the charge / discharge current is continuously monitored.

  In addition, after the process of step S711, the charge / discharge control unit 55 turns on the battery disconnection switch 7 when the output power of the PV panel 1 acquired from the controller 3 becomes equal to or higher than the power consumption of the load 4 (Yes in step S714). (Step S717), the process returns to step S703, and the measurement result of the charge / discharge current is continuously monitored.

[Effect of this embodiment]
As described above, according to the present embodiment, the self-supporting type including the self-supporting power source configured by the PV panel 1, the nickel-metal hydride storage battery 2, and the controller 3, and the load 4 that operates by the power supplied from the self-supporting power source. In the control device 5 installed in the power supply system, the parameter calculation unit 52 uses a plurality of fluctuation patterns (degradation degree fluctuations) of the measured voltage and the remaining capacity with constant charge / discharge current and temperature of storage batteries having different deterioration degrees. Pattern) as teacher data, and by substituting it into the relational expression based on the ANN model, the remaining capacity output parameter for determining the remaining capacity output function and the deterioration level output parameter for determining the deterioration level output function Calculate and store in the parameter storage unit 52.

  Then, after the start of operation of the self-supporting power source, the charge / discharge current, temperature, and voltage of the nickel-metal hydride storage battery 2 are measured at regular intervals in a stable period in which the change amount of the charge / discharge current is within a predetermined range over a predetermined time. The remaining capacity calculation unit 53 and the deterioration level calculation unit 54 calculate the remaining capacity and the deterioration level at a plurality of points in time using the remaining capacity output parameter and the deterioration level output parameter stored in the parameter storage unit 52. Further, since the average remaining capacity and the average deterioration degree are calculated, the parameters of the ANN model calculated using the teacher data consisting of the actual measurement values in the environment corresponding to the stable period, the nickel hydride storage battery 2 of the stable period The remaining capacity and the degree of deterioration can be calculated from the measured values of charge / discharge current, battery temperature and battery voltage. The remaining capacity of the nickel-metal hydride storage battery 2 constituting the mold power becomes possible to accurately estimate. Furthermore, by using the deterioration degree variation pattern, it is possible to accurately estimate the remaining capacity in consideration of the deterioration degree, and it is also possible to accurately estimate the deterioration degree based on the remaining capacity.

  In addition, since the remaining capacity and the degree of deterioration are calculated at a plurality of points in the stable period, it is possible to estimate the remaining capacity and the degree of deterioration with higher accuracy.

  Further, the charge / discharge control unit 55 determines whether the battery disconnection switch 7 is used when the average deterioration level is lower than the set value for battery replacement, when the average remaining capacity is near full charge, when the average remaining capacity is lower than the set threshold value. Since the battery is turned off, it is possible to prompt the administrator to replace the battery, to prevent overcharge or to prevent overdischarge, and to reliably protect the nickel metal hydride storage battery 2 electrically. .

[Comparative example]
Next, the usefulness of the proposed method disclosed in the present embodiment will be described with reference to FIGS. FIG. 8 is a diagram for explaining a model used in the comparative example, FIG. 9 is a diagram for explaining a combination of teacher data used in the comparative example, and FIG. 10 is a diagram in the comparative example. FIG. 11 is a diagram for explaining the calculated remaining capacity output parameters, and FIGS. 11 and 12 are diagrams for explaining the comparison results.

In this comparative example, as shown in FIG. 8, a model for estimating only the remaining capacity was used. That is, "P _1: the charging and discharging current", "P ₂ :( cell) temperature" and type "P ₃ :( battery) voltage", the intermediate layer consisting of five functions of "Q ₁ to Q _5" Thus, “R ₁ : remaining capacity (SOC: State of charge)” is output as an ANN model.

  Further, in this comparative example, as shown in FIG. 9, only the nickel-metal hydride storage battery 2 without deterioration is used, and furthermore, the variation from case 1 to case 7 for each of the seven combinations in which only the environmental temperature and the discharge current are changed. The pattern was measured.

By using these seven variation patterns as teacher data, in this comparative example, as shown in FIG. 10A, 15 functions that define the function for outputting the intermediate layer “Q _{1 to} Q ₅ ” are defined. The weighting factors “V ₁₁ ” to “V ₃₅ ” and five biases “B ₁ ” to “B ₅ ” are calculated, and the output layers “R _{1 to} R ₂ ” are set as shown in FIG. Five weighting factors “W ₁₁ ” to “W ₅₁ ” and one bias “C ₁ ” that define a function for output were calculated.

  A graph in which the relationship between the remaining capacity (SOC) calculated by the remaining capacity output function determined by the remaining capacity output function shown in FIG. 10 and the voltage is plotted is indicated by a solid line or a dotted line, and the measured value is indicated by a circle. And shown in FIG.

  FIG. 11 is a comparison of calculated values and actual measured values when “discharge current and environmental temperature” are “1 A, 15 ° C.”, “1 A, 25 ° C.”, and “1 A, 35 ° C.”, respectively. 12 compares the calculated value and the actual measurement value when the “discharge current and ambient temperature” are “2A, 15 ° C.”, “2A, 25 ° C.”, “3A, 15 ° C.”, and “3A, 25 ° C.”, respectively. It is a thing.

  As shown in FIG. 11 and FIG. 12, there is data that is partly distant from the measured value immediately before full charge (remaining capacity = 1), but the maximum charge is determined to be about 3% as an error. Is a sufficiently possible range, and in other parts, the error between the calculated value and the actually measured value is small. That is, as in the method of the present invention, by measuring teacher data corresponding to the stable period in advance and calculating parameters, the charge / discharge current, battery temperature, and battery voltage can be input during the stable period during operation. It was proved that the remaining capacity can be estimated with high accuracy.

  In the above-described embodiment, the battery is disconnected by calculating the average remaining capacity and the average deterioration degree from the measured values at a plurality of points in time and comparing them with the “set value for storage battery replacement, the value near full charge, the set threshold”. Although the case where the switch 7 is controlled has been described, the present invention is not limited to this, and the remaining capacity using the least square method is calculated from the plurality of remaining capacity and the degree of deterioration calculated from the measured values at a plurality of time points. And by calculating a predicted value of the deterioration degree with time, the time to reach the “set value for battery replacement”, “value near full charge” or “set threshold value” is predicted, and the battery disconnection switch 7 is It may be a case of controlling.

  In the above-described embodiment, the case where the battery disconnection switch 7 is controlled by a plurality of remaining capacities and deterioration levels calculated from measured values at a plurality of points in time has been described. However, the present invention is not limited to this. Alternatively, the battery disconnection switch 7 may be controlled using the current remaining capacity and the degree of deterioration calculated from the measured values measured during the stable period.

  In the above-described embodiment, the case where the control device 5 calculates the parameters from the teacher data has been described. However, the present invention is not limited to this. For example, in the device other than the control device 5, the teacher The parameter may be calculated from the data, and the calculation result may be stored in the control device 5.

  Further, in this embodiment, the case where the storage battery constituting the self-supporting power source is a nickel metal hydride storage battery has been described, but the present invention is not limited to this, and the storage battery constituting the self-supporting power source is, for example, It may be a case of a lead storage battery, a nickel cadmium storage battery, a lithium storage battery, or the like. That is, according to the present invention, it is possible to accurately estimate the remaining capacity of any storage battery and the degree of deterioration based on the remaining capacity.

  Further, each component of each illustrated apparatus is functionally conceptual, and does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution / integration of each device is not limited to that shown in the figure, and all or a part thereof may be functionally or physically distributed or arbitrarily distributed in arbitrary units according to various loads or usage conditions. Can be integrated and configured. Further, all or any part of each processing function performed in each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware by wired logic.

  The remaining capacity estimation method described in this embodiment can be realized by executing a program prepared in advance on a computer such as a personal computer or a workstation. This program can be distributed via a network such as the Internet. The program can also be executed by being recorded on a computer-readable recording medium such as a hard disk, a flexible disk (FD), a CD-ROM, an MO, and a DVD and being read from the recording medium by the computer.

  As described above, the remaining capacity estimation method and the remaining capacity estimation apparatus according to the present invention are the remaining capacity of the storage battery in the self-supporting power source configured by the solar battery and the storage battery that performs charging / discharging using the power generated by the solar battery. Is particularly useful for estimating the remaining capacity of the storage battery with high accuracy.

It is a figure for demonstrating the structure of the self-supporting power supply system in a present Example. It is a figure for demonstrating the nickel hydride storage battery used in a present Example. It is a figure for demonstrating an example of teacher data. It is a figure for demonstrating the combination of teacher data. It is a figure for demonstrating the model used for a parameter calculation part. It is a flowchart for demonstrating the parameter calculation process of the control apparatus in a present Example. It is a flowchart for demonstrating the process after the independent power supply operation start of the control apparatus in a present Example. It is a figure for demonstrating the model used in the comparative example. It is a figure for demonstrating the combination of the teacher data used in the comparative example. It is a figure for demonstrating the parameter for remaining capacity output calculated in the comparative example. It is a figure (1) for demonstrating a comparison result. It is FIG. (2) for demonstrating a comparison result.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 PV panel 2 Nickel metal hydride storage battery 3 Controller 4 Load 5 Control apparatus 51 Parameter calculation part 52 Parameter memory | storage part 53 Remaining capacity calculation part 54 Deterioration degree calculation part 55 Charging / discharging control part 6 Shunt resistance 7 Battery isolation | separation switch 8 Load isolation | separation switch

Claims (4)

In a self-supporting power source composed of a solar battery that generates power by sunlight and a storage battery that charges and discharges using the power generated by the solar battery, a remaining capacity estimation method that estimates the remaining capacity of the storage battery,
It is data consisting of measured values in an environment corresponding to a stable period in which the amount of change in the charge / discharge current for the storage battery is within a predetermined range over a predetermined time, and the temperature of the storage battery and the charge / discharge current for the storage battery are constant By using, as teacher data, the voltage of the storage battery and the variation pattern of the remaining capacity measured in advance for each of a plurality of combinations set to be, the charge / discharge current, the temperature of the storage battery, and the voltage of the storage battery A parameter calculating step for calculating a remaining capacity output parameter for determining a remaining capacity output function with the input as the input and the remaining capacity as an output;
After starting the operation of the self-supporting power source, a determination step of determining whether or not a between front Symbol plateau,
When the determination step determines the stable period, the remaining capacity output determined by the measured values of the charge / discharge current, temperature, and voltage of the storage battery and the remaining capacity output parameter calculated by the parameter calculation step A remaining capacity calculating step for calculating a remaining capacity in the stable period of the storage battery by using a function;
When the remaining capacity calculated by the remaining capacity calculating step is near the full charge of the storage battery, a control step for performing control to stop the charging current from the solar battery;
The remaining capacity estimation method characterized by including. The parameter calculation step uses the deterioration level variation patterns, which are the variation patterns for each of the storage batteries having different degradation levels, measured in advance for each of the plurality of combinations, as the teacher data, so that the remaining capacity output parameter is obtained. While calculating, the charge / discharge current, the temperature of the storage battery, and the voltage of the storage battery as inputs, further calculating a deterioration degree output parameter for determining a deterioration degree output function that outputs the deterioration degree,
The remaining capacity calculating step uses the remaining capacity output function determined by the remaining capacity output parameter calculated by the parameter calculating step using each of the deterioration degree variation patterns, so that the remaining capacity is calculated in the stable period of the storage battery. To calculate the remaining capacity of
In the stable period, by using the measured values of the charge / discharge current, temperature and voltage of the storage battery, and the deterioration level output function determined by the deterioration level output parameter calculated by the parameter calculation step, The remaining capacity estimating method according to claim 1, further comprising a deterioration degree calculating step of calculating a deterioration degree based on the remaining capacity in the stable period.   The remaining capacity calculating step and the deterioration degree calculating step include the remaining amount of the storage battery at the plurality of time points from the measured values of the charge / discharge current, temperature, and voltage of the storage battery measured at the plurality of time points in the stable period. 3. The remaining capacity estimating method according to claim 2, wherein the capacity and the degree of deterioration are respectively calculated. In a self-supporting power source composed of a solar battery that generates power by sunlight and a storage battery that charges and discharges using the power generated by the solar battery, a remaining capacity estimation device that estimates the remaining capacity of the storage battery,
It is data consisting of measured values in an environment corresponding to a stable period in which the amount of change in the charge / discharge current for the storage battery is within a predetermined range over a predetermined time, and the temperature of the storage battery and the charge / discharge current for the storage battery are constant By using, as teacher data, the voltage of the storage battery and the variation pattern of the remaining capacity measured in advance for each of a plurality of combinations set to be, the charge / discharge current, the temperature of the storage battery, and the voltage of the storage battery A parameter calculation means for calculating a remaining capacity output parameter for determining a remaining capacity output function with the input as the input and the remaining capacity as an output;
After starting the operation of the free-standing power, judging means for judging whether or not a between front Symbol plateau,
When the determination unit determines the stable period, the remaining capacity output determined by the measured values of the charge / discharge current, temperature, and voltage of the storage battery and the remaining capacity output parameter calculated by the parameter calculation unit A remaining capacity calculating means for calculating a remaining capacity in the stable period of the storage battery by using a function;
Control means for performing control to stop the charging current from the solar battery when the remaining capacity calculated by the remaining capacity calculator is close to full charge of the storage battery;
A remaining capacity estimation device comprising:

Images