JP7192648B2 - power supply, power system - Google Patents

Description

The present invention relates to a power supply system mounted on a vehicle and a power supply device applied to this power supply system.

BACKGROUND ART As a power supply system mounted on a vehicle, a configuration is known in which two batteries, a first storage battery (sub-battery) and a second storage battery (main battery), are mounted as power supplies. These two storage batteries are connected in parallel via a relay, the second storage battery is connected to a starter and a motor generator, and the first storage battery is connected to various electric loads in which a voltage drop is not allowed.

In addition, for the purpose of improving fuel efficiency and reducing gas emissions, idling stop control is implemented to automatically stop the engine when predetermined automatic stop conditions are met, and then restart the engine when predetermined restart conditions are met. Power systems are known that do. In this power supply system, the electric power of the first storage battery is used to drive the motor generator when the engine is started for the first time, and the electric power of the second storage battery is used to drive the motor generator when the engine is restarted. .

The technique described in Patent Literature 1 discloses a power supply system that calculates the internal resistance of the second storage battery after the first start-up using the first storage battery, in order to avoid restart failure of the engine. In this power supply system, the internal resistance of the second storage battery is calculated in a state in which a current of a predetermined value or more is supplied to the second storage battery, such as when power assist is started, and the internal resistance is less than a predetermined threshold. Then, the restart of the engine by power supply from the second storage battery is permitted. This prevents the engine from being properly restarted.

JP 2017-25709 A

If the current supplied to the second storage battery is not large, the internal resistance of the second storage battery at restart cannot be calculated properly. For example, since the current that flows during power assist is smaller than the current that flows during restart, there is a problem that the internal resistance of the second storage battery during restart cannot be properly calculated using the current that flows during power assist. On the other hand, if the current that flows during power assist is increased to the same level as the current that flows during restart in order to calculate the internal resistance of the second storage battery during restart, the application of power to the vehicle will be excessive, affecting vehicle behavior. There was a problem with

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object thereof is to provide a power supply device and a power supply system capable of properly calculating the internal resistance of the second storage battery without affecting the behavior of the vehicle.

A first means for solving the above problems is mounted in a vehicle that automatically stops and restarts an engine according to a predetermined condition, is connected in parallel to a rotating electric machine, and supplies power when the engine is first started. and a second storage battery used for power supply when restarting the engine after automatic stop, the power supply device applied to a power supply system, wherein the first time the engine a drive control unit that puts the rotating electrical machine into a power running state by power supply from the second storage battery in a low efficiency state in which the efficiency of the rotating electrical machine is a predetermined value or less after startup; a resistance calculation unit that calculates an internal resistance of the second storage battery when the rotating electric machine is in a power running state in an efficient state.

In a vehicle having an idling stop function, after the initial start-up using the power of the first storage battery, the restart using the power of the second storage battery is appropriately performed. In this case, it is desirable that the engine is automatically stopped after grasping the deterioration state of the second storage battery. In this regard, in the above configuration, the internal resistance of the second storage battery is calculated when the rotating electrical machine is placed in the power running state by power supply from the second storage battery in a low-efficiency state in which the efficiency of the rotating electrical machine is equal to or lower than a predetermined value. made it The "powering drive state" includes a state in which energization is performed to cause the armature winding of the rotating electric machine to perform a powering operation, and a state in which energization is performed in a state in which no powering operation occurs.

By putting the rotary electric machine into the power running state under the low efficiency state, compared with the case where the rotary electric machine is put into the power running state under the condition that is not in the low efficiency state, the power to the vehicle is kept in a state that does not increase while the second storage battery is charged. The current flowing can be increased. In other words, for example, even during power assist, it is possible to increase the current flowing through the second storage battery to the same level as during restart while suppressing an increase in the power of the vehicle. As a result, the internal resistance of the second storage battery can be properly calculated without affecting the driving of the vehicle.

In the second means, the rotating electric machine performs power assist when a predetermined assist condition is satisfied while the vehicle is running, and the drive control unit, when the assist condition is not satisfied, The rotating electric machine is brought into a power running state under the low efficiency state.

The rotating electric machine performs power assist when a predetermined assist condition is satisfied, and does not perform power assist when the assist condition is not satisfied. According to the above configuration, the internal resistance of the second storage battery is calculated by putting the rotating electrical machine into the power running state in the low-efficiency state during the rest period of the rotating electrical machine in which the power assist is not performed. As a result, the internal resistance of the second storage battery can be properly calculated by effectively utilizing the rotating electric machine during the idle period.

In a third means, the drive control unit puts the rotating electric machine in the power running drive state assuming that the state is the low-efficiency state when the engine speed is higher than a predetermined speed.

When the engine speed is higher than the predetermined speed, the amount of increase in the engine speed due to application of power to the vehicle is suppressed compared to when the engine speed is lower than the predetermined speed. In other words, the efficiency of the rotary electric machine is in a low efficiency state where the efficiency is equal to or less than a predetermined value. Therefore, by calculating the internal resistance of the second storage battery when the engine speed is higher than the predetermined speed, the internal resistance of the second storage battery can be properly calculated without affecting the driving of the vehicle.

In a fourth means, when the temperature of the rotating electrical machine is higher than a predetermined temperature, the drive control section determines that the rotating electrical machine is in the low-efficiency state and puts the rotating electrical machine in the power running state.

When the temperature of the rotating electrical machine is higher than the predetermined temperature, heat loss in the rotating electrical machine suppresses the amount of increase in the engine speed due to application of power to the vehicle compared to when the temperature is lower than the predetermined temperature. In other words, the efficiency of the rotary electric machine is in a low efficiency state where the efficiency is equal to or less than a predetermined value. Therefore, by calculating the internal resistance of the second storage battery when the temperature of the rotating electric machine is higher than the predetermined temperature, the internal resistance of the second storage battery can be properly calculated without affecting the driving of the vehicle.

In a fifth means, the drive control unit puts the rotating electrical machine into a power running state while causing current to flow only through the d-axis of the d-axis and the q-axis of the rotating electrical machine.

When current flows only through the d-axis of the rotating electrical machine, torque is not generated in the rotating electrical machine, so the amount of increase in the engine speed is suppressed. In other words, the efficiency of the rotary electric machine is in a low efficiency state where the efficiency is equal to or less than a predetermined value. Therefore, by calculating the internal resistance of the second storage battery in a state in which current flows only through the d-axis of the rotary electric machine, the internal resistance of the second storage battery can be properly calculated without affecting the driving of the vehicle.

A sixth means includes a restart determination unit that determines whether or not to permit the restart by power supply from the second storage battery based on the internal resistance calculated by the resistance calculation unit.

According to the above configuration, the idling stop control can be appropriately performed after grasping the state such as deterioration of the second storage battery.

A seventh means is a power supply system mounted on a vehicle that automatically stops and restarts an engine in accordance with a predetermined condition, comprising: a rotating electrical machine; A first storage battery that is used to supply power when the engine is automatically stopped, a second storage battery that is used to supply power when the engine is restarted after being automatically stopped, and the efficiency of the rotating electric machine after the engine is started for the first time. a drive control unit that puts the rotating electric machine into a power running state by power supply from the second storage battery under a low efficiency state below a predetermined level; and a power running drive of the rotating electric machine under the low efficiency state by the drive control unit. and a resistance calculation unit that calculates an internal resistance of the second storage battery when the state is set.

In the above configuration, the internal resistance of the second storage battery is calculated when the rotating electrical machine is in a power running state by power supply from the second storage battery in a low-efficiency state in which the efficiency of the rotating electrical machine is equal to or less than a predetermined value. As a result, the current flowing through the second storage battery can be increased while the power to the vehicle is not increased, and the internal resistance of the second storage battery can be properly calculated without affecting the driving of the vehicle.

Schematic configuration diagram of a power supply system. 4 is a flowchart showing the procedure of control processing according to the first embodiment; 4 is a time chart showing an example of control processing; FIG. 4 is a diagram showing the relationship between differential current and differential voltage; The figure which shows the relationship between the rotation speed of a rotary electric machine, and the torque of a rotary electric machine. 8 is a flowchart showing the procedure of control processing according to the second embodiment; FIG. 4 is a diagram showing the relationship between the temperature of the rotating electric machine and the heat loss of the rotating electric machine; 10 is a flowchart showing the procedure of control processing according to the third embodiment;

Embodiments embodying the present invention will be described below with reference to the drawings. A vehicle equipped with the power supply system 100 of the present embodiment runs using the engine 30 as a drive source, and has a so-called idling stop function.

(First embodiment)
As shown in FIG. 1, a power supply system 100 includes a rotating electric machine 10, a lead storage battery 11, a lithium ion storage battery 12, a starter 13, an electric load 14, a current detection section 15, a voltage detection section 16, a first switch 21, a second switch, and a 22 and a third switch 23 . Among these, the lithium ion storage battery 12, the first switch 21, and the second switch 22 are housed in a housing (housing case) (not shown) to be integrated and configured as a battery unit U. In addition, in this embodiment, the lead storage battery 11 corresponds to a "1st storage battery", and the lithium ion storage battery 12 corresponds to a "2nd storage battery."

The battery unit U is provided with a first terminal T1 and a second terminal T2 as external terminals. The lead-acid battery 11 and the electric load 14 are connected to the first terminal T1, and the rotary electric machine 10 and the starter 13 are connected to the second terminal T2. Both the terminals T1 and T2 are large-current input/output terminals through which input/output currents of the rotary electric machine 10 flow.

The rotating shaft of the rotating electric machine 10 is drivingly connected to an engine output shaft (not shown) by a belt or the like. causes the engine output shaft to rotate. In this case, the rotary electric machine 10 has a power generation function of generating power (regenerative power generation) by rotation of the engine output shaft and the axle, and a power running function of applying power to the engine output shaft. For example, an ISG (Integrated Starter Generator) is used for the rotating electric machine 10 .

The lead storage battery 11 and the lithium ion storage battery 12 are electrically connected in parallel to the rotating electrical machine 10 , and the storage batteries 11 and 12 can be charged with the electric power generated by the rotating electrical machine 10 . Further, the rotary electric machine 10 is configured to apply power to the engine 30 (power running operation) by power feeding from the storage batteries 11 and 12 .

The lead-acid battery 11 is a well-known general-purpose battery. For example, lead dioxide (PbO2) is used as the positive electrode active material of the lead storage battery 11, and lead (Pb) is used as the negative electrode active material. Sulfuric acid (H2SO4) is used as the electrolyte. The lead-acid battery 11 is configured by connecting in series a plurality of battery cells composed of these electrodes. In this embodiment, the storage capacity of the lead-acid battery 11 is set to be larger than that of the lithium-ion storage battery 12 .

Compared to the lead-acid battery 11, the lithium-ion battery 12 has a smaller internal resistance RL in an unused state (new article), a smaller power loss during charging and discharging, and a higher output density and energy density (higher power acceptance). ) is a high-density battery.

For example, an oxide containing lithium (lithium metal composite oxide) is used as the positive electrode active material of the lithium ion storage battery 12 . Specific examples include LiCoO2, LiMn2O4, LiNiO2, LiFePO4 and the like. Carbon (C), graphite, lithium titanate (for example, LixTiO2), an alloy containing Si or Su, or the like is used for the negative electrode active material of the lithium ion storage battery 12 . An organic electrolytic solution is used as the electrolytic solution of the lithium ion storage battery 12 . The lithium ion storage battery 12 is configured by connecting in series a plurality of battery cells composed of these electrodes.

Reference numerals 11a and 12a in FIG. 1 represent battery cell assemblies of the lead-acid battery 11 and the lithium-ion storage battery 12, and reference numerals 11b and 12b represent internal resistances of the lead-acid battery 11 and the lithium-ion storage battery 12, respectively. Further, in the following description, the open-circuit voltage V0 of the storage battery is the voltage generated by the battery cell assemblies 11a and 12a.

The battery unit U is provided with a first connection path L1 and a second connection path L2 that interconnect the terminals T1 and T2 and the lithium ion storage battery 12 as intra-unit electrical paths. A first switch 21 is provided on a first connection path L1 that connects the first terminal T1 and the second terminal T2, and a connection point N1 (battery connection point) on the first connection path L1 and a lithium ion A second switch 22 is provided on a second connection path L2 that connects with the storage battery 12 .

For example, semiconductor switches such as P-channel MOSFETs and N-channel MOSFETs are used for the first switch 21 and the second switch 22 .

Further, in the power supply system 100, a bypass path L3 is provided to enable connection between the lead-acid battery 11 and the rotary electric machine 10 without going through the first switch 21. As shown in FIG. The bypass path L3 bypasses the battery unit U and connects an electric path connected to the first terminal T1 (a path connected to the lead-acid battery 11 or the like) and an electric path connected to the second terminal T2 (the rotating electric machine 10 ) are provided to electrically connect the

A third switch 23 is provided on the bypass path L3 to cut off or connect the connection between the lead-acid battery 11 and the rotating electrical machine 10 . For example, a normally closed relay switch is used for the third switch 23 . Note that the bypass path L3 and the third switch 23 can be provided in the battery unit U so as to bypass the first switch 21 .

The starter 13 is a starting device that starts the engine 30 . When the ignition switch (not shown) of the vehicle is turned on and the starter 13 is turned on, the engine 30 is started with electric power supplied from the lead-acid battery 11 .

The electrical load 14 includes a constant-voltage demanding load that requires the voltage of supplied power to be generally constant or at least stable so that it fluctuates within a predetermined range, and a general load other than the constant-voltage load. .

To explain the electric load 14 in detail, the constant-voltage required load includes a running load related to running of the vehicle and a load other than the running load. The running load includes a braking device, an oil pump of an automatic transmission, a fuel pump, an electric power steering, and the like. Loads other than those for traveling include a navigation device, a display device for displaying meters and the like, an audio device, and the like. General loads include loads with a relatively wide operating voltage range compared to loads requiring constant voltage, such as headlights, windshield wipers, ventilation fans for air conditioners, and defroster heaters for rear windshields. is mentioned.

The current detection unit 15 is connected in series with the lithium ion storage battery 12 and detects a charging/discharging current IL flowing through the lithium ion storage battery 12 . The voltage detection unit 16 is connected in parallel to the lithium ion storage battery 12 and detects a terminal voltage VL applied to the lithium ion storage battery 12 .

The rotary electric machine 10 performs a power running operation to apply power to the engine output shaft. For example, when a predetermined assist condition is satisfied while the vehicle is running, power is applied to the engine output shaft to perform power assist. Here, the assist condition is, for example, the condition that the vehicle is accelerating at a low speed. In addition, power is applied to the engine output shaft when restarting from an automatic stop by idling stop control.

The rotary electric machine 10 is in a state in which power is not applied to the engine 30 by driving the rotary electric machine 10 when the vehicle is in steady running or automatically stopped. Further, when the vehicle accelerates, or when the engine 30 is restarted after being automatically stopped, power is applied to the engine 30 by driving the rotary electric machine 10 .

Further, the rotary electric machine 10 also serves as a generator that generates power using the rotational energy of the engine output shaft. For example, when the rotor of the rotary electric machine 10 is rotated by the engine output shaft, an alternating current is induced in the stator coils according to the excitation current flowing through the rotor coils, and is converted into a direct current by a rectifier (not shown). In the rotating electric machine 10, the exciting current flowing through the rotor coil is adjusted by the regulator, so that the voltage of the generated direct current is adjusted to a predetermined voltage.

Electric power generated by the rotating electric machine 10 is supplied to the electric load 14 and also supplied to the lead storage battery 11 and the lithium ion storage battery 12 . When the engine 30 is stopped and the rotary electric machine 10 is not generating power, power is supplied from the lead storage battery 11 and the lithium ion storage battery 12 to the electric load 14 . The amount of discharge from the lead storage battery 11 and the lithium ion storage battery 12 to the electric load 14 and the amount of charge from the rotary electric machine 10 are appropriately adjusted so that the state of charge (SOC) does not become overcharged or discharged. there is

A rotation detector 17 is provided in the engine 30 . The rotation detection unit 17 detects an engine rotation speed NE, which is the rotation speed of the engine 30 per unit time. Further, the rotating electric machine 10 is provided with a temperature detection section 18 . Temperature detection unit 18 detects temperature YM of rotating electric machine 10 .

The control unit 40 performs various processes in the power supply system 100 . For example, the control unit 40 drives the starter 13 to drive the engine 30 when determining that there is an initial start request based on the signal from the ignition switch. In addition, in this embodiment, the control part 40 corresponds to a "power supply device." At this time, the starter 13 is driven by power supply from the lead-acid battery 11 .

Further, the control unit 40 performs idling stop control. As is well known, the idling stop control automatically stops the engine 30 when a predetermined automatic stop condition is satisfied, and restarts the engine 30 when a predetermined restart condition is satisfied in the automatic stop state. When restarting the engine 30 that has been automatically stopped, the control unit 40 supplies power from the lithium ion storage battery 12 with the first switch 21 turned off and the second switch 22 turned on. The rotary electric machine 10 is driven.

As described above, in the power supply system 100 including the two power sources of the lead storage battery 11 and the lithium ion storage battery 12, when the engine 30 is started for the first time, a stable voltage can be output against the large current discharge at the time of the first start. A lead-acid battery 11 is used. On the other hand, when the engine 30 is restarted after being stopped by the idling stop control, the lithium ion storage battery 12 with good charging/discharging characteristics is used. As a result, the lead-acid battery 11, which has low durability against frequent charging/discharging (cumulative charging/discharging), is prevented from prematurely deteriorating, and the lithium-ion battery 12, which has good charging/discharging characteristics, is used to appropriately restart the engine 30 automatically. can be implemented.

By the way, if the lithium ion storage battery 12 is in a deteriorated state, the lithium ion storage battery 12 may run out of electric power. If the engine 30 is automatically stopped in this deteriorated state, there is concern that restarting the engine 30 by the rotating electrical machine 10 that uses the lithium ion storage battery 12 as a power source will be hindered.

Therefore, it is preferable to calculate the internal resistance RL as the deterioration state of the lithium ion storage battery 12 after the engine 30 is started for the first time. The internal resistance RL can be calculated using, for example, the inter-terminal voltage VL detected by the voltage detector 16 and the charge/discharge current IL detected by the current detector 15 .

When calculating the internal resistance RL after the engine 30 is started for the first time, for example, power assist is performed by driving the rotary electric machine 10 as the vehicle accelerates, and the lithium ion storage battery 12 is energized with the current (discharge current) that flows at that time. do. Then, by calculating the internal resistance RL of the lithium ion storage battery 12 in a state where the lithium ion storage battery 12 is supplied with a current of a predetermined amount or more, such as when power assist is started, for example, it is possible to check the deterioration state of the lithium ion storage battery 12. Conceivable.

However, since the current that flows during power assist is smaller than the current that flows during restart, the internal resistance RL of the lithium ion storage battery 12 during restart cannot be properly calculated using the current that flows during power assist. On the other hand, in order to calculate the internal resistance RL of the lithium-ion storage battery 12 at the time of restart, if the current that flows during power assist is increased to the same level as the current that flows at the time of restart, the power to the vehicle becomes excessive, affecting vehicle behavior. It affects

Therefore, in the present embodiment, the control unit 40 applies power from the rotating electric machine 10 to the engine 30 in a low efficiency state in which the efficiency of the rotating electric machine 10 is equal to or lower than a predetermined value after the engine 30 is started for the first time (power running state). driving state), and the lithium-ion storage battery 12 is energized by the current that flows at that time. Then, control processing is performed to calculate the internal resistance RL of the lithium ion storage battery 12 from the detection result of the electrical change (current, voltage) of the lithium ion storage battery 12 caused by the energization.

As described above, by putting the rotary electric machine 10 into the power running state under the low efficiency state, it is possible to increase the charging/discharging current IL flowing through the lithium ion storage battery 12 without increasing the power to the vehicle. As a result, the internal resistance RL can be properly calculated without affecting the driving of the vehicle.

Next, control processing according to this embodiment will be described with reference to FIG. Here, FIG. 2 is a flow chart showing the procedure of the above processing. This process is repeatedly performed by the control unit 40, for example, in a predetermined cycle under the condition that the starter 13 is turned on and the engine 30 is started for the first time.

When the control process is started, first, in step S10, it is determined whether or not the engine is in a high rotation state in which the engine speed NE is higher than a predetermined speed Nth. Here, the predetermined rotation speed Nth is the minimum rotation speed of the engine 30 when the vehicle is in a high speed state, that is, when the vehicle does not require power assistance, and is, for example, 2000 rpm. If a negative determination is made in step S10, the control process ends without calculating the internal resistance RL.

On the other hand, if an affirmative determination is made in step S10, it is determined in step S12 whether or not the request flag FD is on. Here, the request flag FD is a flag requesting calculation of the internal resistance RL. Specifically, the request flag FD is turned on once during one trip from when the ignition switch is turned on until it is turned off. If a negative determination is made in step S12, the control process ends without calculating the internal resistance RL.

On the other hand, if an affirmative determination is made in step S12, power is applied to engine 30 by driving rotating electric machine 10 in step S14. That is, the rotary electric machine 10 is brought into the power running state while the engine 30 is in the high rotation state. It should be noted that in the present embodiment, the process of step S14 corresponds to the "drive control unit".

In step S16, the internal resistance RL of the lithium ion storage battery 12 is calculated. That is, the internal resistance RL of the lithium-ion storage battery 12 is calculated when the rotary electric machine 10 is in the power running state while the engine 30 is running at high speed. It should be noted that in the present embodiment, the process of step S16 corresponds to the "resistance calculator".

In step S18, it is determined whether the internal resistance RL calculated in step S16 is smaller than a predetermined threshold resistance Rth. Here, the threshold resistance Rth is a resistance value that causes trouble in restarting the engine 30 and is set in advance for each temperature of the lithium ion storage battery 12 .

If an affirmative determination is made in step S18, the permission flag FP is turned on in step S20, and the control process ends. Here, the permission flag FP is a flag that permits restarting of the engine 30 by power supply from the lithium-ion storage battery 12, and is turned on when permitting restarting and turned off when prohibiting restarting. On the other hand, if a negative determination is made in step S18, the permission flag FP is turned off in step S22, and the control process ends. Therefore, it can be said that the process of step S18 is a process of determining whether or not to permit the restart by power supply from the lithium ion storage battery 12 based on the internal resistance RL calculated in step S16. In addition, in this embodiment, the process of step S18 corresponds to a "restart determination unit."

Next, FIG. 3 shows an example of control processing. In FIG. 3, (A) indicates the transition of the engine speed NE, (B) indicates the transition of the high speed flag FH, and (C) indicates the transition of the request flag FD. Further, (D) shows changes in charge/discharge current IL, (E) shows changes in inter-terminal voltage VL, and (F) shows changes in permission flag FP.

Here, the high rotation flag FH is a flag indicating the determination result in step S10 of the control process, and is turned on when an affirmative determination is made in step S10, and turned off when a negative determination is made in step S10. Also, the charging/discharging current IL is described so that the charging current is positive and the discharging current is negative. Note that, in the present embodiment, the permission flag FP is turned off at the start of the control process.

In the illustrated example, when the engine 30 is first started at time t1 and the vehicle starts running, the engine speed NE becomes the starting speed Ns as shown in FIG. 3(A). Here, the starting rotation speed Ns is smaller than the predetermined rotation speed Nth, and is, for example, 1000 rpm.

After that, at time t2, the engine speed NE increases due to the acceleration of the vehicle caused by the user's accelerator operation. On the other hand, since the vehicle is in a low speed state where the engine speed NE is lower than the predetermined speed Nth, power assist is performed by the rotating electric machine 10 as shown in FIGS.

After that, at time t3, when the engine speed NE becomes higher than the predetermined speed Nth, the high speed flag FH is turned on as shown in FIG. 3(B). As a result, the assist condition for the rotating electric machine 10 is no longer satisfied, so the power assist by the rotating electric machine 10 is stopped.

After that, at time t4, as shown in FIG. 3C, when the request flag FD is turned on, the internal resistance RL of the lithium ion storage battery 12 is calculated. In this embodiment, under the condition of high rotation of the engine 30 in which the condition for assisting the rotating electrical machine 10 does not hold, the rotating electrical machine 10 is driven to apply power to the engine 30, and the internal resistance RL of the lithium ion storage battery 12 is calculated.

In this case, since the engine 30 is already in a high rotation state, even if power is applied to the engine 30, an increase in the engine rotation speed NE is suppressed. That is, the efficiency of the rotary electric machine 10, which is indicated by the ratio of the amount of increase in the engine speed NE to the power applied to the engine 30, falls below a predetermined level, resulting in a low efficiency state. In the present embodiment, when the engine speed NE is higher than the predetermined speed Nth, the engine 30 is driven by the rotary electric machine 10, and the internal resistance RL of the lithium-ion storage battery 12 is calculated assuming that the engine is in a low-efficiency state. do.

Specifically, first, charge/discharge current IL and inter-terminal voltage VL at time t4 before power is applied from rotary electric machine 10 to engine 30 are detected. The charging/discharging current IL and the inter-terminal voltage VL at time t4 are hereinafter referred to as voltage V4 and current I4. The voltage V4 is expressed by the following (Equation 1) using the open-circuit voltage V0 of the lithium ion storage battery 12, the current I4, and the internal resistance RL.

V4=V0+I4×RL (Formula 1)
Next, power is applied to the engine 30 by driving the rotary electric machine 10 . As a result, the discharge current increases and the terminal voltage VL decreases. Then, the charging/discharging current IL and the inter-terminal voltage VL are detected at time t5 when a predetermined elapsed period has elapsed from time t4. The charging/discharging current IL and the inter-terminal voltage VL at time t5 are hereinafter referred to as voltage V5 and current I5. The voltage V5 is expressed by the following (Equation 2) using the open-circuit voltage V0 of the lithium ion storage battery 12, the current I5, and the internal resistance RL.

V5=V0+I5×RL (Formula 2)
From (Equation 1) and (Equation 2), the internal resistance RL is expressed by the following (Equation 3) using voltages V4 and V5 and currents I4 and I5.

RL=(I4-I5)/(V4-V5) (Formula 3)
Hereinafter, the current I4 minus the current I5 is referred to as a differential current ΔI, and the voltage V4 minus the voltage V5 is referred to as a differential voltage ΔV (see FIG. 4). In this embodiment, the voltage V5 and the current I5 are detected at a plurality of times t5 with different elapsed periods from the time t4, and a plurality of data indicating the relationship between the differential current ΔI and the differential voltage ΔV are acquired.

After that, at time t6, when the request flag FD is turned off, the application of power from the rotary electric machine 10 to the engine 30 is stopped. Then, the internal resistance RL of the lithium ion storage battery 12 is calculated from the obtained data indicating the relationship between the difference current ΔI and the difference voltage ΔV, and it is determined whether the calculated internal resistance RL is smaller than the threshold resistance Rth. In the illustrated example, the calculated internal resistance RL is smaller than the threshold resistance Rth, so the permission flag FP is turned on at time t6 as shown in FIG. 3(F).

After that, when the vehicle starts to decelerate at time t7, the engine speed NE decreases. After that, at time t8, when the engine speed NE becomes lower than the predetermined speed Nth, the high speed flag FH is turned off.

FIG. 4 is a diagram showing the relationship between the difference current ΔI and the difference voltage ΔV. As shown in FIG. 4, the differential voltage ΔV is linearly proportional to the differential current ΔI, and the larger the differential current ΔI, the larger the differential voltage ΔV. Then, the internal resistance RL is calculated from the slope of the differential voltage ΔV with respect to the differential current ΔI.

Since the differential voltage ΔV is linearly proportional to the differential current ΔI, it is also possible to calculate the internal resistance RL using the charging/discharging current IL and the terminal voltage VL that flow during power assist from time t2 to time t3 in FIG. 3, for example. It is also considered to be.

However, since a large discharge current does not flow during power assist, a large differential current ΔI does not occur. Therefore, as data indicating the relationship between the differential current ΔI and the differential voltage ΔV, only the data group DX in the range where the differential current ΔI is small can be obtained. If only the data group DX can be acquired, as indicated by the broken line in FIG. cannot be calculated properly.

In the present embodiment, the discharge current flowing through the lithium ion storage battery 12 is increased when acquiring data indicating the relationship between the difference current ΔI and the difference voltage ΔV. As a result, data in a range where the difference current ΔI is large can be obtained, and the internal resistance RL can be appropriately calculated regardless of the detection errors of the voltage detection section 16 and the current detection section 15, as indicated by the straight line in FIG.

On the other hand, when the charging/discharging current IL flowing through the lithium ion storage battery 12 is increased, the rotational speed NM of the rotating electrical machine 10 increases, and the torque TM of the rotating electrical machine 10 accordingly increases. If the power applied to the engine 30, that is, the power to the vehicle becomes excessive due to the increase in the torque TM of the rotary electric machine 10, the vehicle behavior is affected and the vehicle behavior cannot be controlled appropriately.

Therefore, in the present embodiment, the charging/discharging current IL flowing through the lithium-ion storage battery 12 is increased under the high rotation state of the engine 30 . FIG. 5 is a diagram showing the relationship between the rotational speed NM of the rotating electrical machine 10 and the torque TM of the rotating electrical machine 10. As shown in FIG. As shown in FIG. 5, the rotary electric machine 10 has a characteristic that the torque TM decreases as the rotation speed NM increases. Here, the rotation speed NM is proportional to the engine rotation speed NE, and a state in which the rotation speed NM is large corresponds to a high rotation state of the engine 30 . Therefore, when the charging/discharging current IL flowing through the lithium ion storage battery 12 is increased while the engine 30 is rotating at a high speed, the torque TM generated in the rotating electric machine 10 is small, so the increase in the engine speed NE is suppressed. As a result, the application of power to the vehicle is suppressed, and the internal resistance RL of the lithium ion storage battery 12 can be properly calculated without affecting the driving of the vehicle.

According to this embodiment detailed above, the following effects can be obtained.

In a vehicle having an idling stop function, after the initial start-up using the power of the lead storage battery 11, the restart using the power of the lithium-ion storage battery 12 is appropriately performed. In this case, it is desirable that the engine 30 is automatically stopped after grasping the state such as deterioration of the lithium ion storage battery 12 . In this respect, in the present embodiment, in a low-efficiency state in which the efficiency of the rotating electrical machine 10 is equal to or lower than a predetermined value, when power is supplied from the lithium ion storage battery 12 to the engine 30 from the rotating electrical machine 10, the lithium ion storage battery 12 The internal resistance RL of is calculated. By applying power from the rotating electric machine 10 to the engine 30 in a low efficiency state, a state in which the power to the vehicle is not increased as compared to applying power from the rotating electric machine 10 to the engine 30 under a non-low efficiency state. The charging/discharging current IL flowing through the lithium ion storage battery 12 can be increased while maintaining the As a result, the internal resistance RL of the lithium ion storage battery 12 can be properly calculated without affecting the driving of the vehicle.

- The rotary electric machine 10 performs power assist when a predetermined assist condition is satisfied, and does not perform power assist when the assist condition is not satisfied. In the present embodiment, the internal resistance RL of the lithium-ion storage battery 12 is calculated by applying power from the rotating electrical machine 10 to the engine 30 in a low-efficiency state during the idle period of the rotating electrical machine 10 in which the power assist is not performed. As a result, the internal resistance RL of the lithium-ion storage battery 12 can be properly calculated by effectively utilizing the rotating electric machine 10 during the idle period.

Specifically, when the engine speed NE is higher than the predetermined speed Nth, the rotary electric machine 10 is in a rest period (time t3 to t8 in FIG. 3). In this pause period, since the engine speed NE is higher than the predetermined speed Nth, the amount of increase in the engine speed NE due to application of power to the vehicle is suppressed compared to when the engine speed NE is lower than the predetermined speed Nth. In other words, the efficiency of the rotary electric machine 10 is in a low efficiency state where the efficiency is equal to or less than a predetermined value. Therefore, by calculating the internal resistance RL of the lithium ion storage battery 12 during this idle period, the internal resistance RL of the lithium ion storage battery 12 can be properly calculated without affecting the driving of the vehicle.

- In the present embodiment, it is determined whether or not restarting of the engine 30 by power supply from the lithium ion storage battery 12 is permitted based on the calculated internal resistance RL. Therefore, the idling stop control can be appropriately performed after grasping the state such as deterioration of the lithium ion storage battery 12 .

(Second embodiment)
The second embodiment will be described below with reference to FIGS. 6 and 7, focusing on differences from the first embodiment.

This embodiment differs from the first embodiment in control processing. The control process of the present embodiment differs from the control process of the first embodiment in that the charging/discharging current IL flowing through the lithium ion storage battery 12 is increased based on the temperature YM of the rotary electric machine 10 .

FIG. 6 shows a flowchart of control processing according to the present embodiment. In FIG. 6, for the sake of convenience, the same processing as the processing shown in FIG. 2 is given the same reference numerals, and the description thereof is omitted.

In this embodiment, when the control process is started, first, in step S30, it is determined whether or not the temperature YM of the rotating electric machine 10 is in a high temperature state higher than the predetermined temperature Yth. Here, the predetermined temperature Yth is the minimum temperature at which the heat loss HL of the rotating electrical machine 10 becomes excessive and the efficiency of the rotating electrical machine 10 becomes equal to or less than a predetermined temperature. If a negative determination is made in step S10, the control process ends without calculating the internal resistance RL. On the other hand, if an affirmative determination is made in step S10, the process proceeds to step S12.

In this embodiment, the charging/discharging current IL flowing through the lithium ion storage battery 12 is increased under the high temperature state of the rotary electric machine 10 . FIG. 7 is a diagram showing the relationship between the temperature YM of the rotating electrical machine 10 and the heat loss HL of the rotating electrical machine 10. As shown in FIG. As shown in FIG. 7, the rotating electrical machine 10 has a characteristic that the higher the temperature YM, the larger the heat loss HL. Therefore, if the charging/discharging current IL flowing through the lithium ion storage battery 12 is increased under the high temperature condition of the rotary electric machine 10, the increase in the engine speed NE is suppressed due to the large heat loss HL, and the application of power to the vehicle is suppressed. be. As a result, the internal resistance RL of the lithium ion storage battery 12 can be properly calculated without affecting the driving of the vehicle.

According to the present embodiment described above, the internal resistance RL of the lithium ion storage battery 12 is calculated when the temperature YM of the rotary electric machine 10 is higher than the predetermined temperature Yth. When the temperature YM of the rotating electrical machine 10 is higher than the predetermined temperature Yth, due to the heat loss HL of the rotating electrical machine 10, the engine rotation speed due to the power to the vehicle is lower than when the temperature YM of the rotating electrical machine 10 is lower than the predetermined temperature Yth. The amount of increase in NE is suppressed. In other words, the efficiency of the rotary electric machine 10 is in a low efficiency state where the efficiency is equal to or less than a predetermined value. Therefore, by calculating the internal resistance RL of the lithium ion storage battery 12 in the high temperature state of the rotary electric machine 10, the internal resistance RL of the lithium ion storage battery 12 can be properly calculated without affecting the driving of the vehicle.

(Third embodiment)
The third embodiment will be described below with reference to FIG. 8, focusing on differences from the first embodiment.

This embodiment differs from the first embodiment in control processing. In the control process of the present embodiment, when increasing the charging/discharging current IL flowing through the lithium-ion storage battery 12, the current is caused to flow only through the d-axis of the d-axis and the q-axis of the rotary electric machine 10, unlike the control process of the first embodiment. Different from control processing.

FIG. 8 shows a flowchart of control processing according to the present embodiment. In FIG. 8, for the sake of convenience, the same processes as those shown in FIG. 2 are given the same reference numerals, and descriptions thereof are omitted.

In this embodiment, when the control process is started, first, in step S12, it is determined whether or not the request flag FD is ON. If a negative determination is made in step S12, the control process ends without calculating the internal resistance RL.

On the other hand, if an affirmative determination is made in step S12, the q-axis current Iq of the rotating electric machine 10 is set to zero in step S40, and the process proceeds to step S14. As a result, only the d-axis current Id flows through the rotating electrical machine 10 when the rotating electrical machine 10 is brought into the power running state in step S14. Note that the "powering drive state" includes a state in which the armature winding of the rotating electrical machine 10 is energized so as to apply power from the rotating electrical machine 10 to the engine 30, and a state in which power is applied to the engine 30. It includes a state in which energization is performed in a state in which application does not occur.

In this embodiment, only the d-axis current Id is passed through the rotary electric machine 10 to increase the charging/discharging current IL flowing through the lithium ion storage battery 12 . When only the d-axis current Id flows through the rotating electrical machine 10, the torque TM is not generated in the rotating electrical machine 10, so an increase in the engine speed NE is suppressed. As a result, the application of power to the vehicle is suppressed, and the internal resistance RL of the lithium ion storage battery 12 can be properly calculated without affecting the driving of the vehicle.

According to the present embodiment described above, the internal resistance RL of the lithium ion storage battery 12 is calculated with only the d-axis current Id flowing through the rotating electric machine 10 . When only the d-axis current Id flows through the rotating electrical machine 10, the torque TM is not generated in the rotating electrical machine 10, so the amount of increase in the engine speed NE is suppressed. In other words, the efficiency of the rotary electric machine 10 is in a low efficiency state where the efficiency is equal to or less than a predetermined value. Therefore, by calculating the internal resistance RL of the lithium ion storage battery 12 in a state where only the d-axis current Id flows through the rotary electric machine 10, the internal resistance RL of the lithium ion storage battery 12 can be properly calculated without affecting the driving of the vehicle. can.

- In the present embodiment, since the torque TM is not generated in the rotary electric machine 10, the internal resistance RL of the lithium ion storage battery 12 can be calculated even when the vehicle is stopped. Therefore, the internal resistance RL of the lithium ion battery 12 can be calculated during the period from the initial start of the engine 30 to the restart using the electric power of the lithium ion battery 12 .

(Other embodiments)
The present invention is not limited to the description of the above embodiments, and may be implemented as follows.

・In the above embodiment, the lead storage battery 11 is used for the initial start of the engine 30, and the lithium ion storage battery 12 is used for starting the engine 30. Not exclusively. When the engine 30 is started for the first time, it is sufficient to use a storage battery that can output a stable voltage against a large current discharge at the time of the first start. A storage battery may be used. For example, a nickel-hydrogen storage battery may be used as the second storage battery. Also, the first storage battery and the second storage battery may be the same type of storage battery.

- In the above-described embodiment, the rotary electric machine 10 has both the power generation function and the power running function, but the rotary electric machine 10 may have only the power running function.

In the above-described embodiment, an example was shown in which the high-speed state of the engine 30, the high-temperature state of the rotating electrical machine 10, and the state in which only the d-axis current Id flows through the rotating electrical machine 10 are separately used as the low-efficiency state. They may be used in combination. For example, the low efficiency state may be determined when two of these three states are established. Specifically, when the engine 30 is running at high speed and the rotating electrical machine 10 is at a high temperature, power may be applied from the rotating electrical machine 10 to the engine 30 to increase the charging/discharging current IL flowing through the lithium ion storage battery 12. .

- These three states may also be used complementarily. For example, if it is determined that neither the high-speed state of the engine 30 nor the high-temperature state of the rotating electric machine 10 will occur within a predetermined period after the engine 30 is started for the first time, only the d-axis current Id is supplied to the rotating electric machine 10. may flow. This makes it easy to calculate the internal resistance RL of the lithium ion battery 12 during the period from the initial start of the engine 30 to the restart using the electric power of the lithium ion battery 12 .

In the above embodiment, an example is shown in which the internal resistance RL of the lithium ion battery 12 is used to determine whether or not to permit restarting of the engine 30 by power supply from the lithium ion battery 12, but the present invention is not limited to this. , for example, determination of deterioration of the lithium-ion storage battery 12, and other uses.

- In the above-described embodiment, an example was shown in which the engine 30 is not restarted when the internal resistance RL of the lithium ion storage battery 12 is equal to or greater than the threshold resistance Rth, but this is not restrictive. For example, the engine 30 may be restarted by power supply from the lead storage battery 11 instead of the lithium ion storage battery 12 . Thereby, even when the lithium-ion storage battery 12 is in a deteriorated state, the idling stop control can be appropriately performed.

- There is a correlation between the internal resistance RL of the lithium ion storage battery 12 and the temperature of the lithium ion storage battery 12 . Therefore, in the above-described first embodiment, a temperature detection unit that detects the temperature of the lithium ion storage battery 12 may be provided, and the calculated internal resistance RL may be corrected based on the temperature detection result of the temperature detection unit. For example, the internal resistance RL is corrected to decrease as the temperature of the lithium ion storage battery 12 increases. Thereby, the calculation accuracy of the internal resistance RL can be improved.

- In the first embodiment, the timing at which the request flag FD is turned on may be earlier than the timing at which the high rotation flag FH is turned on. For example, the request flag FD may be turned on at the same time that the engine 30 is started for the first time. Thereby, the internal resistance RL of the lithium ion storage battery 12 can be calculated early.

DESCRIPTION OF SYMBOLS 10... Rotary electric machine, 11... Lead storage battery, 12... Lithium ion storage battery, 30... Engine, 40... Control part, 100... Power supply system.

Claims (6)

A first storage battery mounted in a vehicle that automatically stops and restarts an engine (30) according to predetermined conditions, is connected in parallel to a rotating electrical machine (10), and is used to supply power when the engine is first started. A power supply device (40) applied to a power supply system (100) comprising (11) and a second storage battery (12) used for power supply when restarting the engine after automatic stop, ,
a drive control unit that brings the rotating electrical machine into a power running state by supplying power from the second storage battery in a low efficiency state where the efficiency of the rotating electrical machine is a predetermined value or less after the engine is started for the first time;
a resistance calculation unit that calculates an internal resistance of the second storage battery when the rotating electric machine is placed in a power running state under the low efficiency state by the drive control unit ,
When the temperature of the rotating electrical machine is higher than a predetermined temperature, the drive control unit determines that the rotating electrical machine is in the low-efficiency state and puts the rotating electrical machine in a power running state . The rotating electric machine performs power assist when a predetermined assist condition is satisfied while the vehicle is running,
The power supply device according to claim 1, wherein the drive control unit brings the rotating electric machine into a power running state under the low efficiency state when the assist condition is not satisfied. 3. The power supply device according to claim 1, wherein, when the engine speed is higher than a predetermined speed, the drive control unit determines that the state is the low efficiency state and puts the rotating electric machine in the power running state. 4. The method according to any one of claims 1 to 3 , wherein the drive control unit puts the rotating electrical machine into a power running state in a state in which only a d-axis of the d-axis and the q-axis of the rotating electrical machine is energized. Power supply as described. The system according to any one of claims 1 to 4 , further comprising a restart determination unit that determines whether or not to permit the restart by power supply from the second storage battery based on the internal resistance calculated by the resistance calculation unit. A power supply according to any one of the preceding paragraphs. A power supply system (100) mounted on a vehicle that automatically stops and restarts an engine (30) according to predetermined conditions,
a rotating electric machine (10);
a first storage battery (11) connected in parallel to the rotating electric machine and used for power supply when the engine is started for the first time;
a second storage battery (12) used for power supply when the engine is restarted after automatic stop;
a drive control unit that brings the rotating electrical machine into a power running state by supplying power from the second storage battery in a low efficiency state where the efficiency of the rotating electrical machine is a predetermined value or less after the engine is started for the first time;
a resistance calculation unit that calculates an internal resistance of the second storage battery when the rotating electric machine is placed in a power running state under the low efficiency state by the drive control unit ,
When the temperature of the rotating electrical machine is higher than a predetermined temperature, the drive control unit determines that the rotating electrical machine is in the low-efficiency state and puts the rotating electrical machine in a power running state .

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