JP2011252821A - Battery control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control charge/discharge of a battery other than a specific battery.SOLUTION: A battery control system for charging a battery by regenerating using a rotary electric machine when a vehicle is decelerated comprises: measuring means that measures voltage and current of a battery; voltage calculating means (step 20) that calculates an open voltage of the battery based on the voltage and current of the battery; resistance calculation means (step 21) that calculates a charged-state internal resistance of the battery based on the open voltage of the battery and on the voltage and current in a charged state of the battery; setting means (step 23) that sets a target charged-state internal resistance based on the available current and voltage from the rotary electric machine and an open voltage of the battery; and control means (step 24-29) that controls charging/discharging of the battery after a regeneration charging based on a comparison result between the charged-state internal resistance and the target charged-state internal resistance.

Description

  The present invention relates to a battery control system.

  A control device for an idle stop vehicle is known in which the SOC (State Of Charge) of a battery is estimated and the idle stop is permitted when the estimated value is equal to or greater than a predetermined value (see, for example, Patent Document 1). ).

JP 2007-056745 A

  However, in the above-described conventional control device, for example, when a battery other than a specific battery is connected and the SOC estimation error increases, there is a possibility that the battery charge / discharge control including the idle stop determination cannot be performed correctly.

(1) The invention of claim 1 is a battery control system in which a battery is regenerated and recharged by a rotating electrical machine when the vehicle is decelerated. The battery is based on the voltage and current of the measuring means for measuring the voltage and current of the battery. Voltage calculating means for calculating the open circuit voltage of the battery, resistance calculating means for calculating the internal resistance during charging of the battery based on the open circuit voltage of the battery and the voltage and current of the battery during charging, and the current and voltage that can be supplied by the rotating electrical machine And setting means for setting the target internal resistance during charging based on the open circuit voltage of the battery, and control for controlling charging / discharging of the battery after regenerative charging based on a comparison result between the internal resistance during charging and the internal resistance during target charging Means.
(2) In the battery control system according to claim 1, in the battery control system according to claim 1, the control means supplies the battery power after regenerative charging when the internal resistance during charging is larger than the internal resistance during charging. To be discharged.
(3) A third aspect of the present invention is the battery control system according to the second aspect, further comprising integrating means for integrating the charge / discharge amount of the battery, wherein the control means discharges more than the charge amount when the battery is charged. Then end the discharge.
(4) According to a fourth aspect of the present invention, there is provided the battery control system according to the third aspect, wherein the control means is a battery operated by a rotating electrical machine when the degree of change in internal resistance during charging with respect to the amount of battery discharge exceeds a predetermined value. Charge the battery.
(5) The invention according to claim 5 is the battery control system according to any one of claims 1 to 4, wherein the control means performs regenerative charging when the internal resistance during charging is equal to or lower than the internal resistance during charging. The battery is charged later by a rotating electric machine.
(6) According to a sixth aspect of the present invention, in the battery control system according to the fifth aspect, when the amount of charge of the battery by the rotating electrical machine exceeds a predetermined value, the control means ends the charging by the rotating electrical machine.
(7) According to a seventh aspect of the present invention, in the battery control system according to any one of the first to sixth aspects, an SOC detection means for detecting a state of charge (SOC) of the battery and an error of the SOC are calculated. An error calculating means, and when the SOC error is lower than a predetermined value, the control means sets a target SOC corresponding to the target internal resistance during charging and charges the battery based on a comparison result between the SOC and the target SOC. When discharging is controlled and the SOC error is greater than or equal to a predetermined value, charging / discharging of the battery is controlled based on a comparison result between the internal resistance during charging and the internal resistance during target charging.
(8) The invention according to claim 8 is the battery control system according to any one of claims 1 to 7, further comprising detection means for detecting the temperature of the battery, wherein the control means has a temperature of the battery equal to or lower than a predetermined value. In this case, the battery is charged by the rotating electric machine.

  According to the present invention, since charging / discharging control of a battery is performed based on internal resistance at the time of charging of the battery, charging / discharging control of the battery can be correctly performed even when a battery other than a specific battery is connected.

The figure which shows the structure of the battery control system of one embodiment. The flowchart which shows the battery control program of one embodiment A plot of four sets of current and voltage data measured at regular intervals The figure which shows the structure which divides | segments and stores a battery control system in two controllers. Flow chart of battery control program for switching between battery control by SOC and battery control by charging resistance Flowchart showing SOC error calculation routine The figure which shows the charge resistance table of the battery The figure explaining the method of setting target SOC from the charge resistance table of a battery

  A vehicle having a rotating electrical machine and a secondary battery (hereinafter simply referred to as a battery) is decelerated by regenerative braking to charge the battery, and after stopping and regenerating to the battery, charging the battery is continued, An embodiment will be described in which it is determined whether or not the transition to the discharge mode is permitted and the on / off control of the rotating electrical machine is performed.

  In this embodiment, a vehicle is described as an example of a vehicle. However, railway vehicles such as trains, trains, and trains, construction vehicles that are self-propelled in construction machinery, and industries that are self-propelled in industrial machinery. The present invention can also be applied to vehicles and the like.

  In this embodiment, the battery is described by taking a lead battery as an example. However, the battery is not limited to the lead battery as long as it has the same characteristics as the lead battery. Furthermore, in this embodiment, a generator is described as an example of a rotating electrical machine, but an electric motor having a load driving function in addition to a power generation function may be used.

  FIG. 1 shows a configuration of a battery control system according to an embodiment. The battery control system according to one embodiment includes a control unit 100, a battery 101, an ammeter 102, a voltmeter 103, a charging start determination unit 104, an open-circuit voltage calculation unit 105, a charging resistance time series measurement unit 106, a current integration unit 107, A generator supplyable current storage unit 108, a target charging resistance setting unit 109, a discharge start determination unit 110, a discharge end determination unit 111, a generator 112, an auxiliary machine 113, and the like are provided.

  The control part 100 is implement | achieved as a software form performed with the microcomputer of a vehicle controller. The software in the vehicle controller includes a state detection device (battery temperature, current and voltage measurement device) directly connected to the battery 101, a vehicle engine or motor controller, or a generator controller, or various controllers. Realized by a combination of Details of this controller combination will be described later.

  The ammeter 102 measures the charging / discharging current to the battery 101 and transmits the measured current value to the control unit 100. A shunt resistor, a Hall element, or the like can be used for the ammeter 102. The voltmeter 103 measures the voltage between the cathode and the anode of the battery 101, converts it to a digital value, and transmits it to the control unit 100. The generator 112 has an on / off function and a generated voltage adjustment function, and performs charging / discharging of the battery 101 and power supply to the in-vehicle auxiliary machine 113. In this embodiment, the generator 112 maintains a maximum voltage in order to increase the regenerative capability during regeneration. The auxiliary machine 113 is a load of the battery 101 such as a light or a wiper mounted on the vehicle.

  In FIG. 1, in the case of an automobile, a generator is mechanically connected to an engine (not shown) via a belt or the like, and the generator drives a load drive function for starting the engine in addition to the power generation function. (Power running function) On the other hand, in the case of a railway vehicle, the generator is generally a motor generator (motor generator) and has a power generation function and a load drive function. In addition, the construction vehicle and the industrial vehicle may be a generator mechanically connected to an engine or a motor generator.

  FIG. 2 is a flowchart showing a battery control program according to one embodiment. When it is determined by the charge start determination unit 104 of the control unit 100 that the vehicle has started regenerative braking, that is, the discharge current is changed to the charge current by the sign of the current of the battery 101 measured by the ammeter 102, the control unit 100 starts execution of the battery control program.

  In step 20, the open-circuit voltage calculation unit 105 of the control unit 100 calculates the open-circuit voltage of the battery 101, that is, the terminal voltage of the battery 101 when the current is zero. Specifically, it is obtained from time-series measured values of the current and voltage of the battery 101 when the battery 101 shifts from the discharged state to the charged state.

  FIG. 3 is a diagram in which four sets of data of current and voltage measured at regular intervals (for example, every 10 ms) are plotted as an example, the horizontal axis represents current 31 (+ side is charged, − side is discharged), and the vertical axis Represents the voltage 32. Data 33 is current and voltage data measured at the time of discharging before charging, data 34 is current and voltage data measured immediately after the start of charging, data 35 is current and voltage data 10 ms later, and data 36 is 10 ms later. Current and voltage data.

  Since there is no data when the current is 0, the least square line 37 is obtained using the plotted points from the data 33 to the data 36, and the voltage 38 when the current is 0 is obtained from the intercept of the straight line and the vertical axis of the current 0. Ask. In addition, as the least square method, for example, the method introduced in the document “University of Tokyo Faculty of Liberal Arts, Statistics: Introduction to Statistics, University of Tokyo Press, September 25, 2001, 20th edition” can be used. Although FIG. 3 shows an example using four sets of data of current and voltage, it can be obtained using data of at least two sets of current and voltage.

Next, in step 21, the charging resistance (internal resistance when the battery 101 is charged) is obtained by the charging resistance time series measuring unit 106 of the control unit 100. In this embodiment, the charging resistance is calculated by the following equation.
Terminal voltage-Open voltage = Charging resistance x Current ∴ Charging resistance = (Terminal voltage-Open voltage) / Current (1)
In equation (1), the open circuit voltage is the value obtained in step 20, the terminal voltage is the value measured by the voltmeter 103 when the battery 101 is charged, and the current is the value measured by the ammeter 102 when the battery 101 is charged. Use.

  When charging the battery, the charging resistance increases as the charging proceeds, and then the charging resistance has a characteristic of converging to a certain value. Therefore, in this embodiment, the initial value of the charging resistance is not used and the convergence value is used. Alternatively, a value close to that is used for controlling the battery 101.

  Since the terminal voltage and current are affected by noise, a value obtained by applying a weighted moving average (low-pass filter) process to the past charging resistance time series to the equation (1) may be used. As a method of this low-pass filter, for example, the method introduced in the document “Toshio Iwata: Introduction to Practical Digital Filter Design, CQ Publishing” can be used.

  In step 22, it is determined whether or not regeneration has ended. Specifically, the vehicle speed signal is used and the regeneration is terminated when the vehicle speed becomes zero. If regeneration has not been completed, the process returns to step 21; if completed, the process proceeds to step 23.

In step 23, the target charging resistance is calculated by the target charging resistance setting unit 109 of the control unit 100 using the following equation.
Current that can be supplied to the generator x target charging resistance = generator voltage-open voltage ∴ Target charging resistance = (generator voltage-open voltage) / current that can be supplied to the generator (2)

Here, power is actually supplied from the battery 101 to the auxiliary machine 113 such as a vehicle light, and the current may be obtained by the following equation.
Target charging resistance = (generator voltage-open circuit voltage) / (generator supplyable current-auxiliary machine current) (3)
In the equation (3), the auxiliary current is a current that flows to the vehicle auxiliary machine 113 such as a light, and the average of the current of the generator 112 is obtained in a state where the battery 101 described later is not charged or discharged, and the value is May be used. Alternatively, a constant value may be used. Further, as the generator supplyable current, a value stored in advance in the generator supplyable current storage unit 108 of FIG. 1 is used. Further, the generator voltage may be a preset value or an average value of the voltage while the generator 101 is on.

  In step 24, the discharge start determination unit 110 of the control unit 100 determines whether to continue charging the battery 101 or to permit the transition to the discharge mode. In the case of an automobile, this discharge determination is an idling stop determination. When the transition to the discharge mode is permitted, the engine is stopped and discharge from the battery 101 to the in-vehicle auxiliary machine 113 is started.

  In the discharge determination, the target charging resistance calculated in step 23 is compared with the final value of the charging resistance calculated in step 21. If it is determined that the final charging resistance is smaller than the target charging resistance, the process proceeds to step 28. In this case, since the charging resistance of the battery 101 is low and the load on the generator 112 is large, it is necessary to increase the charging resistance until the next regeneration. In step 28, the generator 112 is turned on and charging is continued. In the following step 29, it is determined whether or not the amount of charge accumulated from the end of regeneration to the present (calculated by the current integration unit 107 of the control unit 100 in FIG. 1) exceeds a predetermined threshold value. When the amount exceeds the threshold value, the process proceeds to step 27.

  On the other hand, if it is determined in step 24 that the final charging resistance is greater than or equal to the target charging resistance, the process proceeds to step 25. In this case, since the charging resistance of the battery 101 is high and the generator 112 has a surplus capacity, it is necessary to lower the charging resistance until the next regeneration. In step 25, the generator 112 is turned off to complete the charging. Then, discharge from the battery 101 to the in-vehicle auxiliary machine 113 is started. In subsequent step 26, has the discharge amount (calculated by the current integration unit 107 of the control unit 100) discharged from the end of regeneration to the present increased by α (a predetermined constant) than the charge amount charged during regeneration? It is determined whether or not, and when the discharge amount becomes (charge amount + α) or more, the process proceeds to step 27.

  Here, α may be a half value of the amount of charge charged during the current regeneration, or may be a fixed value of 1 Ah, for example.

  Here, when the charging resistance is compared with the target charging resistance and it is determined whether charging is continued or discharged, charging and discharging may be frequently switched due to a slight difference between the charging resistance and the target charging resistance. In order to avoid such problems, “target charging resistance> charging resistance + ε” is used instead of “target charging resistance> charging resistance”, and “target charging resistance <charging resistance” is used instead of “target charging resistance <charging resistance”. Hysteresis may be given as “−ε”. Here, ε is a predetermined minute resistance.

In step 27, the voltage of the generator 112 is controlled to a voltage at which charging / discharging of the battery 101 does not occur. Specifically, feedback control of the generator voltage is performed based on the current measured by the ammeter 102. For example, the generator voltage may be controlled by the following equation.
V (t + 1) = V (t) −δ × I (t) (4)
In equation (4), V (t) is the generator voltage at time t, I (t) is the current at time t (charge side is +), and δ is a predetermined minute value. In step 27, the generator voltage may be controlled to the open circuit voltage calculated in step 20.

  When the battery control system of the present invention is applied to a vehicle having a battery and a generator, it may be desirable to configure the battery control system of the present invention by diverting equipment and devices mounted on the vehicle as they are. In such a case, the combination of the controller and the sensor in the battery control system of the present invention varies. Therefore, a combination of a controller and a sensor in the battery control system of the present invention will be described.

  As a first configuration, there is a configuration in which the current sensor 102 and the control unit 100 are housed in one controller. As a second configuration, there is a configuration in which the current sensor 102 and the control unit 100 are separated and the control unit 100 is housed in one controller.

  As a third configuration, the current sensor 102, the voltmeter 103, the current integration unit 107, the charging resistance time series measurement unit 106, the open-circuit voltage calculation unit 105, and the charge start determination unit 104 are housed in one controller (battery state detection device). In addition, there is a configuration in which the power generation supplyable current storage unit 108, the target charging resistance setting unit 109, the discharge start determination unit 110, and the discharge end determination unit 111 are housed in another controller (for generator control).

  Further, as a fourth configuration, the voltmeter 103, the current integration unit 107, the charging resistance time series measurement unit 106, the open-circuit voltage calculation unit 105, and the charge start determination unit 104 are housed in one controller (battery state detection device), A configuration may be considered in which the power generation supplyable current storage unit 108, the target charging resistance setting unit 109, the discharge start determination unit 110, and the discharge end determination unit 111 are housed in another controller (for generator control) and the current sensor 102 is attached to the battery 101. It is done.

  FIG. 4 shows an example of a configuration in which the battery control system is divided and stored in two controllers. In this configuration, the ammeter 102 is housed in the battery state detection device 41, and the battery state detection device 41 is attached to the battery 101. In the case of a configuration in which the battery control system is stored in two controllers, communication between the controllers is required. The battery state detection device 41 does not directly control the battery 101, calculates the open circuit voltage, the charging resistance, and the current integral value, and generates the generator controller via the communication unit 42 and the in-vehicle LAN (Local Area Network) 45. The calculation result is transmitted to 43. Further, the battery state detection device 41 receives the generator on signal and resets the current integral value.

  On the other hand, the generator controller 43 executes control necessary for power generation. Specifically, the open circuit voltage, the charging resistance and the current integration value received from the battery state detection device 41, and the regeneration end signal (vehicle speed 0 signal) received from the vehicle controller (not shown) via the communication unit 44 and the in-vehicle LAN 45. ), Voltage adjustment is performed so that the generator 112 is turned on / off and the charge / discharge current of the battery 101 becomes zero. A command for the generator 112 is transmitted to the generator 112 via the communication unit 44 and the in-vehicle LAN 45.

  4 shows an example in which the ammeter 102 is housed in the battery state detection device 41, the ammeter 102 may be configured separately from the battery state detection device 41. In that case, it is not necessary to attach the battery state detection device 41 to the battery 101.

  When the battery control system of the present invention is applied to a railway vehicle such as a train, a train, or a train to realize a railway vehicle station regeneration system, the battery 101 and the battery state detection device in the controller configuration shown in FIG. 41 is installed at the station, and the generator controller 43 is installed on the train. In this case, the in-vehicle auxiliary machine 113 becomes a system.

<< Other Embodiments >>
As described above, in the battery control system according to the embodiment, the discharge determination is performed as to whether to continue charging the battery after the end of regeneration or to allow the transition to the discharge mode. In the case of an automobile, this discharge determination is an idling stop determination. When the transition to the discharge mode is permitted, the engine is stopped and the discharge from the battery to the in-vehicle auxiliary device is started. Conventionally, the SOC table for the open circuit voltage of the battery is stored, the open circuit voltage is obtained, the corresponding SOC is read from the SOC table, and discharge determination is performed based on this SOC to control the charge / discharge of the battery. Here, the SOC characteristics with respect to the open circuit voltage vary depending on the type, model, and specification of the battery, and each battery has its own characteristics. Therefore, accurate control becomes possible by performing charge / discharge control of the battery using the correct SOC table for the battery mounted on the vehicle.

  However, when a battery other than a specific battery having a different type, model, or specification is used, the battery and the characteristic table do not correspond to each other, and an error is included in the SOC read from the SOC table according to the open circuit voltage. Become. Therefore, a device for detecting the SOC accuracy of the battery is added. When the SOC detection accuracy is high, conventional battery charge / discharge control is performed. When the SOC detection accuracy is low, the above-described implementation is performed. Embodiment which performs charge / discharge control of the battery by the charge resistance of form is described.

  The SOC is calculated by measuring the open circuit voltage of the battery immediately after starting the engine of the vehicle and calculating the discharge resistance based on the subsequent change in current and voltage. And based on an open circuit voltage and discharge resistance, SOH (State of Health; deterioration degree of a battery) and initial stage SOC are estimated. Thereafter, the SOC value is updated by integrating the charge / discharge current of the battery. Here, the SOC initial value is obtained by referring to the battery-specific SOC table (see, for example, Japanese Patent Application Laid-Open No. 2008-082990).

  The cause of the inability to maintain the accuracy of the SOC is that the battery corresponding to the SOC table is different in type, model, specification, etc. In addition to the case where a battery other than a specific battery is connected, there is a long time after starting the engine. Over time, current integration errors may accumulate. For this reason, when a battery that does not correspond to the SOC table to be held is connected, or when a long time has elapsed since the start of the vehicle engine, the charging resistance of the above-described embodiment is controlled from the battery control by the SOC. Switch to battery control.

  FIG. 5 is a flowchart of a battery control program for switching between battery control by SOC and battery control by charging resistance. When the engine of the vehicle is started, the control device 100 starts executing the battery control program of FIG. 5 and continues until the vehicle stops and the controller is turned off.

  In step 51, SOC error calculation is performed. Details of this calculation method will be described later. In step 52, the error is determined. If the SOC error is smaller than the determination reference value, the process proceeds to step 53. If the SOC error is greater than the determination reference value, the process proceeds to step 55. Here, a predetermined value is used as the determination reference value. If the SOC error is smaller than the determination reference value, the battery control based on the conventional SOC described above is executed in step 53. On the other hand, if the SOC error is greater than or equal to the determination reference value, in step 55, the battery control using the charging resistance according to the embodiment described above is executed.

  Even when it is determined that the SOC error is smaller than the determination reference value and the battery is controlled by the SOC, the SOC error increases as time passes after the engine is started as described above. It is determined whether or not the measured time T has been exceeded, and when the startup time exceeds the set time T, the battery control using the charging resistor according to the embodiment is switched. The set time T is set to a limit time when the SOC error due to the integration of the charge / discharge current due to the ammeter error (for white noise) exceeds the determination reference value.

  Next, the SOC error calculation method in step 51 of FIG. 5 will be described. FIG. 6 is a flowchart showing an SOC error calculation routine. In step 61, the SOC initial value is calculated. For example, the open circuit voltage of the battery is detected, and the SOC corresponding to the open circuit voltage detection value is read from the SOC characteristic table for the open circuit voltage (see, for example, Japanese Patent Application Laid-Open No. 2008-82990).

Next, in step 62, the SOC initial value is compared with a threshold value. If the SOC initial value is larger than the threshold value, the process proceeds to step 63. If the SOC initial value is less than the threshold value, the process proceeds to step 64. The value obtained by the following formula is set as the threshold value.
Threshold = 100−SOC initial error−ε (5)
In equation (5), the SOC initial error is a value determined by analog-digital conversion errors of the ammeter 102 and the voltmeter 103, an estimation error (preset value) by a table, etc., and ε is when the vehicle is parked. This is the SOC (a value determined by investigating in advance) corresponding to the voltage drop due to self-discharge. A predetermined value such as 95% may be set as the threshold value.

  If the SOC initial value is less than or equal to the threshold value, the generator 112 is turned on in step 64 and the on state is maintained until the battery is fully charged. In the case of a battery, the charging current becomes 0 when the battery is fully charged. If | charging current | <ammeter error, it is determined that the battery is fully charged and the generator 112 is turned off. The ammeter error is a value given in advance according to ammeter specifications.

On the other hand, if the SOC initial value is larger than the threshold value, the generator 112 is turned off in step 63 and the auxiliary machine 113 is discharged until the SOC reaches a certain value, for example, 90%. In step 64 after the end of discharging, the generator 112 is turned on as described above, and the on state is maintained until the battery is fully charged. In step 65, the SOC error is obtained by the following equation.
SOC error = 100−SOC (6)
In the equation (6), the SOC on the right side is a value obtained by updating the SOC initial value by current integration.

  In the flowchart shown in FIG. 6, an example in which the SOC error is obtained by calculation is shown. However, an unevenness or a reflector is attached to a specific battery type (battery type assumed in the SOC calculation of the lead state detection device), and the lead state detection device A device for recognizing the unevenness or the reflector is added to determine whether or not a different type of battery is attached. If it is determined that a different type of battery is connected, the SOC error is set to a large value, for example, a threshold according to equation (5). When a value equal to or greater than the value is set and a specific battery is connected, the SOC error may be set to zero.

  Next, in order to execute the SOC control in step 53 of FIG. 5, it is necessary to set the target SOC. In order to increase the regenerative capability, the target SOC may be a value corresponding to the target charging resistance. In this embodiment, a method of setting the target SOC corresponding to the target charging resistance will be described. When performing charge / discharge control of a battery by SOC, the type, model, specification, etc. of the battery are specified, and the SOC error is small. In this case, a battery charging resistance table as shown in FIG. 7 is held in advance.

  In FIG. 7, the charging resistance table is configured as a matrix of temperature 71 in the horizontal direction and SOC 72 in the vertical direction, and a matrix of charging resistance tables is prepared for each SOH. The unit of charging resistance is mΩ. Here, as the target charging resistance, a value separately calculated by the target charging resistance setting unit 109 shown in FIG. 1 is used. Also, SOH has a correlation with the internal resistance of the battery, and the SOH corresponding to the detected internal resistance value is read from the SOH characteristic table for the internal resistance obtained by measurement in advance (see, for example, Japanese Patent Application Laid-Open No. 2008-082990). Further, the temperature is measured by a thermometer attached to the battery. The SOC corresponding to the target charging resistance (= charging resistance), SOH, and temperature is read from the battery charging resistance table shown in FIG.

The above SOC search method will be specifically described with reference to the table shown in FIG. When the battery temperature is 25 ° C., SOH is 84%, and the target charging resistance is 18 mΩ, a table of SOC 90% and SOC 80% is first extracted. Next, the weighted average value of these two tables is obtained. As the weighted average value, the SOH 80% table is 60%, and the SOH 90% weight is 40%. Next, columns of temperatures 20 ° C. and 30 ° C. are extracted from the table, and a weighted average is obtained. The weighting is a ratio of 1: 1 from 25 ° C. An example of this weighted column is shown in FIG. The SOC closest to 18 mΩ is searched from the column shown in FIG. In this case, the resistance becomes 18.5 mΩ (reference numeral 81) when the SOC is 90%. Since this value is larger than the target charging resistance of 18 mΩ, the value of the resistance of 17 mΩ (reference numeral 82) when the SOC is 85% smaller than this value is also referred to, and the target SOC of 18 mΩ is obtained as the solution of the linear equation.
18−17 = (18.5−17) × (x−85) / (90−85) (7)
In the equation (7), x is a target SOC.

  The solution of equation (7) is x = 88.33, and the target SOC is set to 88.33%. Here, when the target SOC value obtained by the equation (7) is smaller than the SOC value (SOC lower limit value, predetermined value) for ensuring the next engine start, the target SOC is set as the SOC lower limit value. To do. This calculation is performed in the battery state detection device 41 in the case of the controller configuration shown in FIG. The target charging resistance is transmitted to the battery state detection device 41 via the in-vehicle LAN 45 as a value periodically calculated during regeneration by the generator controller 43. The target SOC (and the SOC calculated separately by the battery state detection device 41) is similarly transmitted from the battery state detection device 41 to the generator controller 43 via the in-vehicle LAN 45, and the SOC control is performed by the generator controller 43. To be implemented.

  Next, when the temperature of the battery is low, the internal resistance of the battery increases, and particularly in the case of a vehicle, the engine may not be restarted. For this reason, a thermometer may be attached to the battery, and discharging may be prohibited when the temperature falls below a certain value, for example, 0 ° C., that is, the generator is always turned on for charging.

In addition, in the charge / discharge control of the battery by the charge resistance shown in FIG. 2, if the capacity (Ah) of the connected battery is small or the battery has deteriorated too much, the charge resistance is large and the battery is charged no matter how much discharge is performed. The resistance may not be the target charging resistance. In such a case, the charging resistance R (n) (n is the number of regenerations) at the end of regeneration and the discharge amount Q (n) (n is the number of regenerations) between regenerations are stored. The discharge amount sensitivity of the charging resistor is obtained by
Discharge sensitivity [1 / Ah] = (R (n) −R (n−1)) / (R (n) × Q (n)) (8)
This discharge amount sensitivity represents the degree of change in charge resistance with respect to the discharge amount of the battery.

  When the discharge amount sensitivity obtained by the equation (8) is equal to or greater than the threshold value, it is determined that the charge resistance does not become the target charge resistance no matter how much the discharge is discharged, and the generator is always turned on to charge the battery. This process is performed between step 22 and step 23 in the battery control by the charging resistance shown in FIG. Further, the threshold value is set to a small negative value determined in advance in order to detect a case where the charging resistance increases with discharge.

Next, if the regenerative capacity is increased by reducing the charging resistance, there is a possibility of causing engine start failure by the generator. In order to avoid such problems, the following measures are taken. First, the discharge resistance can be obtained at the first engine start. The discharge resistance can be obtained as the slope of a straight line obtained by the method of least squares based on the time series measured values of current and voltage at the time of starting the engine, similarly to the above-described charging resistance (see FIG. 3). Therefore, the discharge resistance r (n) (n is the number of engine starts) after idling stop and the discharge amount q (n) (n is the number of engine starts) between the engine start and the engine start are stored. The idling stop is determined by whether or not the above relationship is satisfied.
r (n-1) -E (q) × S <discharge resistance limit,
S = {r (n-1) -r (m-2)} / q (n-1): discharge resistance / discharge amount sensitivity (9)
In equation (9), the discharge resistance limit is a discharge resistance that allows a predetermined engine to be started safely,
Open circuit voltage-discharge resistance limit x maximum current when starting the engine = voltage at which the device does not operate (10)
Calculate according to In the equation (10), the voltage at which the apparatus does not move is, for example, 7.2V.

  Here, idling stop is executed when the relationship of equation (9) is satisfied. On the other hand, idling stop is not performed when the relationship of equation (9) is not satisfied. As a specific process, the condition of equation (9) is added as an AND condition to the condition of step 24 of battery control by charging resistance shown in FIG.

  In the above-described embodiments and their modifications, all combinations of the embodiments or the embodiments and the modifications are possible.

  According to the above-described embodiment and its modifications, the following operational effects can be achieved. First, in a battery control system in which a battery is regenerated and charged by a generator when the vehicle decelerates, the battery voltage and current are measured to calculate the battery open voltage, and the battery open voltage and the battery voltage during charge are calculated. The charging resistance of the battery is calculated based on the current and the current, and the target charging resistance is set based on the current and voltage that can be supplied by the generator and the open voltage of the battery. And based on the comparison result between the charging resistance and the target charging resistance, the charging / discharging of the battery after the regenerative charging is controlled, so the charging / discharging control of the battery is performed even when a battery other than a specific battery is connected. Can be done correctly.

  In addition, according to the embodiment and the modification thereof, when the charging resistance is larger than the target charging resistance, the battery power is supplied to the auxiliary machine to be discharged. The charging resistance can be lowered, and the regenerative charging current from the generator can be increased to improve the regenerative efficiency.

  According to one embodiment and its modification, when the charging resistance is less than or equal to the target charging resistance, the battery is charged by the generator after regenerative charging. For example, when the present invention is applied to an automobile, the engine can be reliably restarted after idling stop.

  According to one embodiment and its modification, the SOC of the battery is detected to calculate the SOC error. If the SOC error is lower than a predetermined value, the target SOC is set according to the target charging resistance, and the SOC is calculated. And charging / discharging of the battery based on the comparison result between the charging resistance and the target SOC, and when the SOC error is a predetermined value or more, charging / discharging of the battery is controlled based on the comparison result between the charging resistance and the target charging resistance. Therefore, the battery charge / discharge control by the SOC and the battery charge / discharge control by the charge resistance can be effectively switched by the SOC error. In other words, when the SOC error becomes large, such as when a battery other than a specific battery is connected while normally performing accurate battery charge / discharge control by SOC, accurate charge / discharge control of the battery by charge resistance is performed. Battery charge / discharge control can be continued.

DESCRIPTION OF SYMBOLS 100; Control part, 101; Battery, 102; Ammeter, 103; Voltmeter, 105; Open-circuit voltage calculation part, 106; Charging resistance time series measurement part, 107; Current integration part, 108; 109; target charging resistance setting unit; 110; discharge start determination unit; 111; discharge end determination unit; 112; generator; 113;

Claims (8)

In a battery control system that regenerates by a rotating electric machine and charges a battery when the vehicle decelerates,
Measuring means for measuring the voltage and current of the battery;
Voltage calculating means for calculating an open voltage of the battery based on the voltage and current of the battery;
A resistance calculating means for calculating an internal resistance during charging of the battery based on an open voltage of the battery and a voltage and current of the battery during charging;
Setting means for setting a target charging internal resistance based on a current and voltage that can be supplied by the rotating electrical machine and an open voltage of the battery;
A battery control system comprising: control means for controlling charge / discharge of the battery after regenerative charging based on a comparison result between the internal resistance during charging and the internal resistance during target charging. The battery control system according to claim 1,
When the internal resistance at the time of charging is larger than the internal resistance at the time of target charging, the control means supplies the power of the battery to an auxiliary machine after regenerative charging to discharge the battery. The battery control system according to claim 2,
An integrating means for integrating the charge / discharge amount of the battery;
The battery control system according to claim 1, wherein the control unit terminates the discharge when the discharge exceeds the charge amount at the time of charging the battery. The battery control system according to claim 3,
The battery control system, wherein the control means charges the battery by the rotating electrical machine when the degree of change in the internal resistance during charging with respect to the discharge amount of the battery exceeds a predetermined value. In the battery control system according to any one of claims 1 to 4,
When the internal resistance during charging is equal to or less than the internal resistance during target charging, the control means charges the battery by the rotating electrical machine after regenerative charging. The battery control system according to claim 5, wherein
The battery control system according to claim 1, wherein the control unit terminates charging by the rotating electrical machine when a charge amount of the battery by the rotating electrical machine exceeds a predetermined value. In the battery control system according to any one of claims 1 to 6,
SOC detecting means for detecting SOC (State Of Charge) of the battery;
Error calculating means for calculating the error of the SOC,
When the SOC error is lower than a predetermined value, the control unit sets a target SOC corresponding to the target internal resistance during charging, and charges / discharges the battery based on a comparison result between the SOC and the target SOC. And controlling charging / discharging of the battery based on a comparison result between the internal resistance during charging and the internal resistance during target charging when the SOC error is equal to or greater than the predetermined value. Control system. In the battery control system according to any one of claims 1 to 7,
A detecting means for detecting the temperature of the battery;
The battery control system, wherein the control means charges the battery by the rotating electrical machine when the temperature of the battery is equal to or lower than a predetermined value.

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