JP7119524B2 - power control unit - Google Patents

Description

The present invention relates to a power supply control device applied to a power supply system having an output power supply and a capacitive power supply.

Conventionally, in a power supply system in which an output-type power supply with a relatively large output and a capacity-type power supply with a relatively large amount of storable power are connected so that power can be exchanged by a bidirectional power converter, the operation of the power converter is Controlling power control devices are known. For example, the power supply control device disclosed in Patent Document 1 is applied to a hybrid vehicle power supply system that uses an output type power supply as a high voltage power supply and a capacitive power supply as an intermediate voltage power supply.

In the power supply control device of Patent Document 1, when the road surface on which the vehicle is traveling is upsloping, the SOC of the intermediate voltage power supply decreases and the SOC of the intermediate voltage power supply reaches the lower limit value of the intermediate voltage power supply. The power converter is controlled so that power is supplied to the high voltage power supply. In addition, when the road surface on which the vehicle is traveling is downhill, the power supply control device controls the output-type high-voltage power supply until the SOC of the medium-voltage power supply rises and reaches the upper limit value of the medium-voltage power supply SOC. Control the power converter so that power is supplied to the power supply.

JP 2017-73934 A

In the technique of Document 1, when the road surface on which the vehicle travels is uphill, it is in a high load state, and when it is downhill, it is in a low load state. In the technique disclosed in Document 1, power is not supplied to the output type power supply when the load is low on a downward slope. For example, assume a situation in which a hybrid vehicle travels a short downhill followed by a long uphill. In the technique of Document 1, when the vehicle approaches an uphill, power supply from the capacitive power source to the output power source is started. It may not rise enough. As a result, if the SOC of the output-type power source is low when the vehicle starts running on a hill under high load, the engine starts early, leading to a problem of deterioration in fuel consumption.

SUMMARY OF THE INVENTION The present invention has been created in view of such a point, and an object thereof is to provide a power supply control device that appropriately secures the amount of charge of an output type power supply in preparation for the next run.

The power supply control device of the present invention is mounted on a vehicle, applied to a power supply system comprising a first power supply (50), a second power supply (30), and a power converter (40), and controls the operation of the power converter. . A first power supply is connected to a drive system (600) that drives a motor generator (65). The second power supply has a lower voltage than the first power supply. The power converter exchanges power bi-directionally between the drive system and the first and second power supplies.

The first power supply is an output type power supply having a higher output than the second power supply. The second power supply is a capacitive power supply that can store more power than the first power supply. For example, the first power source is a lithium ion capacitor and the second power source is a lithium ion battery.

The power supply control device has a running state acquisition section (87), a charge determination section (83), and a power converter operation section (84). The running state acquisition unit acquires information related to the running state of the vehicle including vehicle stop or the set running state. The charge determination unit determines the charge amount of the first power supply detected by the first power supply power detector (75), the charge amount of the second power supply detected by the second power supply power detector (73), and the running state acquisition unit. Based on the acquired running state or running setting state of the vehicle, it is determined whether the second power source should charge the first power source. The power converter operation unit operates the power converter according to the determination result of the charging determination unit.

When the driving state or driving setting state of the vehicle is (1) when the vehicle speed is low below a predetermined judgment vehicle speed, or when the accelerator is off, (2) when the shift range is in the P range, or when the shift range is shifted to the P range. When one or more of (3) the power switch is turned off, and (4) the determination time has elapsed since the ready-off state, the charge determination unit determines whether the charge amount of the first power supply has reached the P range. If the charge amount is less than the charge amount threshold, the power converter is operated to charge the first power supply from the second power supply. Determine to stop charging . SOC is typically used as the “ charge amount”.

In the present invention, when the vehicle is parked or stopped, the first power source is charged from the second power source until the charge amount of the first power source reaches the charge amount threshold value (for example, until the first power source is fully charged) in preparation for the next run. As a result, the output-type power source is placed in a high SOC state when the vehicle starts running next time, and the state in which the output-type power source is capable of outputting high power is maintained for as long as possible. Therefore, in the hybrid vehicle, it is possible to prevent the engine from starting early and improve the fuel efficiency.

FIG. 1 is an overall configuration diagram of a power supply system to which power supply control devices according to first to fifth embodiments are applied; The figure which compares the self-discharge characteristic of a lithium ion capacitor and EDLC. 4A and 4B are diagrams for explaining charge control of the output type power supply according to the first embodiment; FIG. 4 is a flowchart of charging control according to the first embodiment; 4 is a time chart of charging control according to the first embodiment; 6 is a time chart of charging control according to the second embodiment; Time chart of charging control according to the third embodiment. The time chart of charge control by 4th Embodiment. FIG. 11 is a diagram for explaining charging control of an output-type power source and an auxiliary power source according to a fifth embodiment; FIG. 11 is a flow chart of charging control according to the fifth embodiment; FIG. FIG. 3 is a characteristic diagram showing the relationship between power supply temperature and power; FIG. 11 is an overall configuration diagram of a power supply system to which a power supply control device according to a sixth embodiment is applied; 10 is a flow chart of charging control according to the sixth embodiment; The time chart explaining prediction of power supply temperature. FIG. 5 is a diagram for explaining setting of a low temperature judgment value; FIG. 11 is a time chart of charging control according to the sixth embodiment; FIG.

A plurality of embodiments of the power control device will be described below with reference to the drawings. In a plurality of embodiments, substantially the same configurations or substantially the same steps in flowcharts are denoted by the same reference numerals or the same step numbers, and descriptions thereof are omitted. Also, the first to sixth embodiments will be collectively referred to as "the present embodiment". The power supply control device of the present embodiment is applied to a power supply system mounted on a hybrid vehicle using an engine and a motor generator (hereinafter referred to as "MG") as power sources. Hereinafter, the generic code of the power supply system to which this embodiment is applied is assumed to be "10". When distinguishing the power supply system in each embodiment, the number of the embodiment is attached to the third digit following "10" to the code of the power supply system.

[Configuration of power supply system]
First, FIG. 1 will be referred to for the overall configuration common to the power supply control devices of the first to fifth embodiments. In FIG. 1, the generic code "10" is used as the code of the power supply system to which each embodiment is applied. Power supply system 10 is provided between a high voltage system including drive system 600 and the like and a low voltage system including auxiliary load 15 and the like.

Drive system 600 is a system that drives MG 65, which is the power source of the vehicle, with electric power converted by inverter 60. FIG. During the power running operation of MG 65 , DC power supplied from power supply system 10 is converted into AC power by inverter 60 and supplied to MG 65 . Further, during the regenerative operation of MG 65 , AC power generated by MG 65 is converted into DC power by inverter 60 and regenerated by power supply system 10 . Depending on the system, a boost converter may be provided on the input side of the inverter.

The auxiliary load 15 is a device such as an electric power steering device, a power window device, a blower, a fan, etc., which performs various functions different from those of the main machine, and is driven by the low-voltage DC power of the auxiliary power supply 20 .

The power supply system 10 includes a first power supply 50, a second power supply 30, a bidirectional DCDC converter (hereinafter "bidirectional DDC"), power supply power detectors 75 and 73, and a power supply control device 80 as basic elements. The first power supply 50 is connected to a drive system 600 of a high voltage system and exchanges power with the drive system 600 . The second power supply 30 has a lower voltage than the first power supply 50 .

The bi-directional DDC 40 as a “power converter” exchanges power bi-directionally between the drive system 600 and the first power supply 50 and the second power supply 30 . A first power supply power detector 75 and a second power supply power detector 73 detect the power of the first power supply 50 and the second power supply 30, respectively, by, for example, the product of current and voltage. Power control device 80 controls the operation of bidirectional DDC 40 .

In the present embodiment, an output type power supply such as a lithium ion capacitor (hereinafter "LiC") is used as the first power supply 50, and a capacitive power supply such as a lithium ion battery (hereinafter "LiB") is used as the second power supply 30. . An output type power supply has a larger output than a capacitive type power supply, and a capacitive type power supply has a large amount of electric power that can be stored compared to an output type power supply. The voltage of the first power supply 50, which is an output power supply, is 200V, for example, and the voltage of the second power supply 30, which is a capacitive power supply, is 48V, for example. In the drawings and some parts of the specification, they are described as "output type first power supply 50" and "capacitance type second power supply 30".

As described above, the power supply system 10 is premised on a configuration in which a capacitor such as LiC having excellent power storage performance is used for the first power supply 50, which is an output type power supply. FIG. 2 shows a comparison of self-discharge characteristics between LiC and EDLC (that is, electric double layer capacitor). EDLC has a problem that the electric charge is discharged early and the SOC is reduced to about half after about 500 hours.

On the other hand, the self-discharge characteristic of LiC is as small as about 5% decrease in SOC after about 3 months. As described above, LiC has excellent power storage performance, can maintain the amount of stored power even when left standing, and is superior to LiB in power storage performance. In addition, since LiC can be discharged without chemical reaction, output performance at low temperature is also excellent. Focusing on the excellent output and power storage performance of LiC, it is possible to improve the performance of the next run by storing power in LiC before the vehicle is left unattended.

Further, the power supply system 10 includes an auxiliary power supply 20 connected to the auxiliary load 15, an auxiliary step-down DDC 25 for stepping down the voltage of the second power supply 30 and supplying the voltage to the auxiliary power supply 20, and the electric power of the auxiliary power supply 20. includes an accessory power supply power detector 72 that detects the A lead battery (PbB) or a lithium battery (LiB) with a voltage of about 14 V, for example, is used as the auxiliary power supply 20 .

In this specification, for convenience, the 200V class voltage of the first power supply 50 is referred to as "high voltage", the 48V class voltage of the second power supply 30 is referred to as "medium voltage", and the 14V class voltage of the auxiliary power supply 20 is referred to as "low voltage". ”. The bi-directional DDC 40 exchanges power between the first power supply 50 connected to the high voltage system and the second power supply 30 and auxiliary power supply 20 connected to the medium and low voltage system.

The power supply control device 80 has a running state acquisition unit 87, a charging determination unit 83, and a DDC operation unit 84 as a "power converter operation unit". The running state acquisition unit 87 acquires vehicle speed information, shift range information, power switch information, etc. as information relating to the running state of the vehicle including the vehicle stop or the running setting state.

Based on the charge amount of the first power source 50 and the second power source 30 acquired from the power source power detection units 75 and 73 and the running state or running setting state of the vehicle acquired from the running state acquisition unit 87, the charge determination unit 83 It is determined whether or not the second power supply 30 is to charge the first power supply 50 . DDC operation unit 84 operates bidirectional DDC 40 according to the determination result of charging determination unit 83 . In the fifth embodiment, the charge determination unit 83 further acquires the charge amount of the auxiliary power supply 20 from the auxiliary power supply power detection unit 72, and the DDC operation unit 44 further operates the step-down DDC 25 for auxiliary equipment.

The power supply system 10 further includes an automatic activation device 90 that automatically activates and deactivates the power control device 80 . For example, the automatic activation device 90 activates and deactivates the power control device 80 while the vehicle is parked.

By the way, when the parked vehicle starts running next time, if the SOC of the first power supply 50 is low, the power that can be output is limited at an early stage. There is Therefore, the power supply system 10 of the present embodiment aims to control the power supply between the power supplies so as not to impair the output performance of the output type first power supply 50 (that is, the capacitor) when the vehicle starts running next time.

For this reason, the power supply control device 80 operates the bidirectional DDC 40 to operate the second capacitive power supply 30 (i.e., battery ) to the output-type first power source 50 to charge the first power source 50 . Therefore, the first power supply 50 is charged even while the vehicle is parked (that is, while the power supply is left unused). Hereinafter, control for charging (or supplementary charging) from the second power supply 30 to the first power supply 50 is referred to as "charging control". Next, the configuration and effects of the "charging control" of each embodiment will be described in order.

(First embodiment)
A power supply system according to the first embodiment will be described with reference to FIGS. 3 to 5. FIG. First, FIG. 3 will be referred to regarding the charging control of the first embodiment performed by the power supply system 101 . In FIG. 3, solid arrows indicate power supplies that are actively implemented. If the first power source 50 is not fully charged during the period from the end of the previous run to the parking stop, the second power source 30 is controlled to charge the first power source 50 .

Next, charging control according to the first embodiment will be described with reference to the flowchart of FIG. In the description of the flow charts below, the symbol S stands for "step". In S<b>71 , the charge determination unit 83 determines whether or not to start charging control based on the “information regarding the running state or the set running state” acquired from the running state acquisition unit 87 . For example, the charge determination unit 83 determines YES in S71 by using the power switch OFF operation as a charge control start trigger. On the other hand, if the power switch is not turned off, the charge determination unit 83 determines NO in S71 and waits.

In S72A, the charge determination unit 83 determines whether or not there is a charge request based on whether or not the SOC of the first power supply 50 is less than the full charge threshold. If the first power source 50 is not in a fully charged state, it is better to charge the power source system 10 before it is stopped. On the other hand, if the first power supply 50 is fully charged, no charging request is generated, so the determination in S72A is NO, and the process ends.

In S73, it is determined whether or not charging can be performed. If charging is possible, YES is determined in S73, and the process proceeds to S74. Typically, the SOC of the second power supply 30 exceeds the lower limit value, and it is determined that charging can be performed when there is a surplus SOC. On the other hand, if the SOC of the second power source 30 is equal to or lower than the lower limit value, the second power source 30 does not have sufficient energy and charging cannot be performed. If the loop from the NO determination in S75 to S73 is repeated, the charging determination unit 83 ends charging when the SOC of the second power supply 30 drops to the lower limit.

As another case where it is determined that charging from the second power source 30 to the first power source 50 is not possible, excessive power restriction may be applied. For example, after accelerating or decelerating, electric power is limited in order to suppress deterioration of the battery. Alternatively, power is also limited when the temperature of the second power supply 30 or the bidirectional DDC 40 is lower or higher than a predetermined range. If the second power supply 30 or the bi-directional DDC 40 has a high temperature, the charging may be performed after waiting for cooling. In addition, it is determined that charging cannot be performed even when a system abnormality occurs.

If it is determined in S73 that charging can be performed, the DDC operation unit 84 operates the bidirectional DDC 40 in S74 to supply power from the second power supply 30 to the first power supply 50 for charging. In S75, it is determined whether or not the first power source 50 has reached full charge. When the first power supply 50 is fully charged, the DDC operation unit 84 stops the operation of the bi-directional DDC 40 to end charging, and shifts to a normal system shutdown sequence. If the first power supply 50 has not reached full charge, the process returns to before S73 to continue charging.

Next, the setting of the parameters constituting this charging control and the control method will be supplemented.

[1] "Upper Limit SOC/Lower Limit SOC" and "Full Charge Threshold"
The range of the control SOC is often set to the range from the upper limit SOC to the lower limit SOC in consideration of the control margin. Note that the SOC value varies depending on the definition. For example, the upper limit SOC may be defined as the value of SOC 100%. Therefore, it should be noted that unless the definition is clear, the state of charge of the power supply cannot be accurately grasped only by the numerical value of the SOC. The full charge threshold may be set to the same value as the upper limit SOC, or may be set to a value obtained by adding a predetermined margin to the upper limit SOC.

[2] SOC Estimation Generally, SOC, which is obtained by dividing the remaining capacity [Ah] of the battery by the fully charged capacity [Ah] of the battery and expressed as a percentage, is used as the charge amount of the battery. The SOC of a battery can be obtained from a relationship map between the electromotive voltage and the SOC before charging and discharging the battery. However, charging and discharging of the battery causes an apparent change in the internal resistance due to a temporary decrease in the amount of chemical reaction, and various SOC estimation methods have been proposed. For example, a current integration method for tracking the amount of charge transfer, a battery reaction model, a battery adaptive filter model, and the like are known. Also, the SOC of a capacitor is generally estimated using voltage because it is hardly affected by a chemical reaction as in a battery. In this embodiment, a well-known SOC estimation method may be used.

[3] Full charge capacity The full charge capacity of the battery used for SOC estimation is grasped from the design specification values at the time of shipment, but it decreases due to battery deterioration, so it is necessary to estimate and update the full charge capacity each time. be. As for the method of estimating the full charge capacity, known techniques include a method of measuring the full charge capacity by continuously discharging/charging in a wide range from the upper and lower voltage limits, and a method of obtaining the full charge capacity using a battery reaction model or an adaptive filter model. there is

In addition to "degradation", there is a concept of "charge depth" for batteries. For example, when the battery is cold, the internal resistance of the battery increases significantly, and charging does not proceed within a predetermined time. In this method, a charge/discharge test is performed under predetermined conditions, and a full charge capacity map corresponding to battery temperature is created. In this embodiment, a well-known full charge capacity estimation method may be used. Then, the SOC of the battery may be estimated based on the full charge capacity updated each time the battery deteriorates.

[4] Charging Method The power supply control device 80 can charge the first power supply 50 in the following order.

<1> For example, if the SOC of the first power supply 50 is lower than the full-charge threshold value triggered by turning off the power switch while parking, the charging determination unit 83 uses the surplus SOC of the second power supply 30. Then, charging from the second power supply 30 to the first power supply 50 is started. Since this charging is performed after the second power supply 30 and the first power supply 50 have been warmed up in the previous run, there is an advantage that Joule loss is reduced and charging efficiency can be maintained.

<2> Power is supplied from the second power supply 30 to the first power supply 50 by the bidirectional DDC 40 . The power to be supplied is variable according to the state of devices such as the second power source 30 (that is, battery) and the two-way DDC 40 . However, if the first power supply 50 approaches the full-charge threshold even if a command to supply a predetermined power is issued, the power to be supplied is limited by the power limit for overcharge prevention. Therefore, the power supplied at the time when the full charge threshold is reached is approximately 0 kW.

<3> When the SOC of the second power supply 30 is lower than the lower limit SOC, the charging determination unit 83 suspends charging from the second power supply 30 to the first power supply 50 .

<4> When the SOC of the first power supply 50 reaches the full-charge threshold, the charging determination unit 83 determines that charging is complete, and turns off the ready. However, if an abnormality occurs during the charging period, the charging determination unit 83 suspends charging and turns off the ready.

Next, refer to the time chart in FIG. FIG. 5 shows changes over time in the ready (“READY” in the figure) state, charge control start request, bidirectional DDC output power, and SOC of the first power supply 50 and the second power supply 30 . The "+" of the bidirectional DDC output power means power supply from the capacitive second power supply 30 to the output type first power supply 50 (that is, charging the first power supply 50), and the "-" means the output type first power supply. Power supply from the power supply 50 to the capacitive second power supply 30 (that is, discharge of the first power supply 50). The difference between the current value of the first power supply SOC at the start of charging control and the full charge threshold indicates the required charging amount. Further, the difference between the current value of the second power supply SOC and the lower limit value at the start of charging control indicates the chargeable amount (that is, the amount of surplus SOC).

In the initial period before time ts1, the ready state is on, the charge control start request is off, and the bidirectional DDC output power is slightly on the "+" side of zero. Also, the first power supply SOC is a value slightly higher than the lower limit, and the second power supply SOC is a value sufficiently higher than the lower limit. In the first embodiment, power switch information is acquired by the running state acquisition unit 87 . At time ts1 when the power switch is turned off, the charge start control request is turned on, the bidirectional DDC 40 starts operating, and charging from the second power supply 30 to the first power supply 50 starts.

As a result, the first power supply SOC increases and the second power supply SOC decreases from the control start time ts1. Thereafter, at time te2 when the first power supply SOC reaches the full charge threshold, the charge control start request is turned off, and charging ends. Here, in the comparative example indicated by the dashed line, the ready-off state is performed simultaneously with the power switch-off operation, whereas in the first embodiment, after the power switch-off operation, the ready-on state continues until the charging completion time te1, and charging control is executed. be. Note that the bidirectional DDC output power gradually decreases slightly before the charging completion time te1.

As described above, in the first embodiment, power is supplied from the second power supply 30 to the first power supply 50 by using the power switch OFF operation at the start of parking as a control start trigger. The charging time is immediately after parking starts, and as an effect, the frequency of missing regeneration is low. Also, the charging time can be secured, and the first power source 50 can be fully charged while the vehicle is parked.

As described above, in the first embodiment, the power supply control device 80 uses the power switch OFF operation as a control start trigger, and if the first power supply 50 is not in a fully charged state during the period from the end of the previous run to the parking stop, the The second power source 30 is controlled to charge the first power source 50 . As a result, the power supply control device 80 puts the output-type first power supply 50 into the high SOC state when the next running is started, and maintains the state in which the output power of the first power supply 50 is high as long as possible, so that the engine starts early. can be delayed. As a result, fuel efficiency of the vehicle is improved.

(Second, third and fourth embodiments)
In the charging start determination of S72, the time charts of FIGS. 6, 7, and 8 are used for the second, third, and fourth embodiments, in which information other than the power switch OFF operation in the first embodiment is used as the charging control start trigger, respectively. will be described with reference to

In the second embodiment shown in FIG. 6, the shift position information is acquired by the running state acquiring section 87 . For example, charging from the second power supply 30 to the first power supply 50 is started at time ts2 when the shift range is changed from the P range to the D range. After that, charging ends at time te2 when the first power supply SOC reaches the full charge threshold.

As described above, in the second embodiment, the shift range from the second power supply 30 to the first power supply 50 is switched from the second power supply 30 to the first power supply 50 using the fact that the shift range is the P range or the fact that the shift range is changed to or from the P range as a control start trigger. Powered. The charging timing is the period from when the vehicle is operated from the D range to the P range before parking until the time the vehicle is ready-off, or when the vehicle is operated from the P range to the D range after startup. As an effect, the frequency of regeneration failure is low.

In the third embodiment shown in FIG. 7, the vehicle speed information is acquired by the running state acquisition unit 87 and compared with the determined vehicle speed. In the early stage of FIG. 7, the vehicle speed is relatively high, i.e., the medium-high speed state. The bi-directional DDC output power is “−” and power is regenerated from the first power supply 50 to the second power supply 30 . During deceleration, the regenerated electric power further increases, and both the first power supply SOC and the second power supply SOC increase. At time tj3, the vehicle speed falls below the determination vehicle speed, and thereafter, when the vehicle speed continues below the determination vehicle speed for the determination period Tj, charging from the second power supply 30 to the first power supply 50 is started at time ts3. After that, charging ends at time te3 when the first power supply SOC reaches the full charge threshold.

As described above, in the third embodiment, power is supplied from the second power supply 30 to the first power supply 50 when the vehicle speed is lower than the determination vehicle speed or when the accelerator is off as a control start trigger. Note that if the vehicle speed change or the output change is large during the determination period Tj, the charging determination unit 83 may wait for charging. The charging period is the period from the time of deceleration regeneration to the period before parking or stopping, or the period from the time of starting after activation. As an effect, the battery can be charged while driving, and the remaining amount can be supplemented after deceleration regeneration. Also, a long charging time can be ensured.

In the fourth embodiment shown in FIG. 8, the driving state acquisition unit 87 acquires the parking time calculated from the parking start time tp4 due to the ready-off, and compares it with the judgment time. At the beginning of FIG. 8, the battery is ready-on, and the first power supply SOC and the second power supply SOC are almost fully charged. During parking after the parking start time tp4, the first power supply SOC and the second power supply SOC gradually decrease due to self-discharge. At time ts4 when the parking time reaches the judgment time, the automatic activation device 90 automatically activates the power supply control device 80 of the power supply system 10, and charging from the second power supply 30 to the first power supply 50 is started.

After that, at time te4 when the first power supply SOC reaches the full charge threshold, the output power of the bidirectional DDC 40 is turned off, charging is completed, and the parking time is reset. When the determination time elapses again from time te4, charging is started again. As described above, in the fourth embodiment, power is supplied from the second power supply 30 to the first power supply 50 using the fact that the predetermined determination time has elapsed since the ready-off as the control start trigger. The charging time is during parking. As an effect, in addition to the same effect as the first embodiment, supplementary charging can be performed even for self-discharge during long-term parking. Also, by providing the automatic activation device 90, the first power supply 50 can be automatically charged while the vehicle is parked.

The "vehicle driving state or driving setting state" used as a charging control start trigger in the first to fourth embodiments can be arranged along the time flow from deceleration to parking while the vehicle is running, as follows. . By selecting and combining these charging timings, it is possible to freely configure control and ensure charging frequency.

(1) When the vehicle speed is lower than or equal to a predetermined determination vehicle speed, or when the accelerator is off (second embodiment)
(2) When the shift range is the P range, or when the range is changed to or from the P range (third embodiment)
(3) When the power switch is turned off (first embodiment)
(4) After elapse of determination time from ready-off (fourth embodiment)

(Fifth embodiment)
Next, a fifth embodiment will be described with reference to FIGS. 9 and 10. FIG. FIG. 9 shows the charging control of the fifth embodiment implemented by the power supply system 105. As shown in FIG. The power supply control device 80 charges the first power supply 50 from the capacitive second power supply 30 and also charges the auxiliary power supply 20 from the second power supply 30 via the auxiliary step-down DDC 25 .

There is a possibility that the SOC of auxiliary battery 20 may be depleted while the vehicle is left unused for a long period of time. To solve this problem, there is a control technology that activates the power supply system 10 by the automatic activation device 90 and charges the auxiliary battery 20 while the vehicle is parked. However, if the charging control of the first power supply 50 and the charging control of the auxiliary power supply 20 according to the fourth embodiment are operated separately during parking, it is not desirable in terms of efficiency, for example, the startup time during parking becomes long. Become.

Therefore, in the fifth embodiment, both the first power supply 50 and the auxiliary power supply 20 are charged at the same time with respect to the above problem. This reduces losses by shortening the start-up time. In addition, since the second power supply 30 (that is, the battery) is warmed up by increasing the charging power, the charging efficiency is advantageous. Furthermore, by reducing the SOC of the second power supply 30 (that is, the battery), there are advantages such as the effect of suppressing storage deterioration.

Specifically, when there is a request to charge the first power supply 50 or the auxiliary power supply 20, the power supply control device 80 operates the bidirectional DDC 40 to supply power from the second power supply 30 to the first power supply 50 for charging. Electric power is supplied from the second power supply 30 to the auxiliary power supply 20 for charging. Especially when charging is performed while the vehicle is parked or stopped, the automatic activation device 90 activates the power supply control device 80 when there is a request to charge at least one of the first power supply 50 and the auxiliary power supply 20 . Then, the automatic activation device 90 stops the power control device 80 when charging of both power sources 50 and 20 is completed. As a result, it is possible to reduce the loss caused by lengthening the useless start-up time.

The flowchart of FIG. 10 shows charging control according to the fifth embodiment. The charge start determination by the charge control start trigger in S71 is the same as in the first embodiment shown in FIG. In S72B, the charging determination unit 83 determines whether or not there is a request to charge the first power supply 50 or a request to charge the auxiliary power supply 20. FIG. In the case of YES in S72B, the charging determination unit 83 determines to start charging control of both power sources 50 and 20, and proceeds to S73 and S76. S73, S74, and S75 regarding charging to the first power source 50 are the same as those in FIG. 4, and therefore are omitted.

Regarding charging of the auxiliary power supply 20, in S76, it is determined whether or not there is an excess SOC of the second power supply 30, as in S73. If it is determined YES in S76, charging from the second power supply 30 to the auxiliary power supply 20 is carried out in S77. On the other hand, if the determination in S76 is NO, charging is prohibited, and the process proceeds to S79.

In S78, it is determined whether or not the SOC of auxiliary power supply 20 has reached the full charge threshold. In the case of NO, the process returns to S76 to continue charging, and in the case of YES, the charging of the auxiliary power supply 20 is completed. In S79, it is determined whether charging of both the first power supply 50 and the auxiliary power supply 20 has been completed. If NO, wait; if YES, shutdown of power system 105 is allowed.

(Sixth embodiment)
Next, a sixth embodiment will be described with reference to FIGS. 11 to 16. FIG. In carrying out the charging control according to the above embodiment, when the vehicle is left and the power source is cold, even if power is supplied from the capacitive second power source 30 to the output type first power source 50 to charge the first power source 50, , there is a problem that the power limit is activated and the charging time becomes extremely long.

As shown in FIG. 11, in principle, the capacitor has relatively good power characteristics at low temperatures because there is no mass transfer inside the cell. On the other hand, with regard to batteries, depending on the type, the power characteristics at low temperatures may be significantly reduced. As a result, there arises a problem that due to power shortage, it becomes impossible to charge the capacitor between the two power sources, that is, from the battery. For example, even in the temperature range before transition to warm-up, the power of the capacitive power supply used for charging between the two power supplies cannot be secured. That is, if an attempt is made to charge the output power source from the capacitive power source after the capacitive power source has cooled down, charging cannot be performed, leading to deterioration in fuel efficiency.

Therefore, in the sixth embodiment, the first power source 50 is charged from the second power source 30 in preparation for the next run before the capacitive second power source 30 cools while the vehicle is left unattended. As shown in FIG. 12, a power supply control device 806 of the sixth embodiment further includes a power supply temperature estimator 88 in addition to the power supply control device 80 of FIG. The power supply temperature estimating unit 88 uses one or more of the parking start time information, driving history, navigation information, and weather information to estimate the predicted power supply temperature, which is the predicted temperature of the second power supply 30 at the next start of driving. . Here, the parking start information includes the power supply temperature and the parking start time at the start of parking. The travel history is used to estimate the next travel start time. The navigation information indicates the parking position of the vehicle. The weather information includes the expected temperature for each time zone at the parking position.

Hereinafter, the "power supply temperature" in the sixth embodiment basically means the temperature of the capacitive second power supply 30, that is, the "battery temperature". Since the temperature environments of the first power supply 50 and the second power supply 30 are considered to be the same, the "power supply temperature" may be interpreted as the common temperature of both the power supplies 50 and 30 .

In the sixth embodiment, the temperature of the power supply at the start of the next run is estimated in order to use the second power supply 30 warmed up in the previous run and to utilize the state in which the outputtable power is high. Then, when it is predicted that the second power source 30 will be in a low temperature state at the start of the next running, if the first power source 50 is not in a fully charged state within a predetermined period before the power source cools down, the bidirectional DDC 40 is operated to operate the second power source. Power is supplied from the power source 30 to the first power source 50 to charge the first power source 50 .

If the power supply is in a low temperature state when the vehicle starts running next time, it will not be possible to take out power from the power supply, resulting in significant performance degradation such as a decrease in output and deterioration in fuel efficiency. Considering the degree of impact, this is a point worth noting. Depending on the way of thinking, the charging control may be positively performed only when the power supply is expected to be in a low temperature state when the next running is started.

FIG. 13 shows charging control according to the sixth embodiment. In S61, the power supply temperature estimating unit 88 estimates the predicted power supply temperature at the time of next startup, that is, at the next start of running. Subsequently, in S62, the power supply temperature estimator 88 determines whether or not the second power supply 30 is in a low temperature state when the vehicle starts running next time based on the predicted power supply temperature. The details of the method of estimating the predicted power supply temperature in S61 and the method of determining the low temperature at the next start-up in S62 will be described later.

When it is determined as YES in S62, charging is permitted, and the process proceeds to the charging control start determination in S71. S71 to S75 are the same as the processing of the first embodiment shown in FIG. If the charging control is not started, it is determined as NO in S71, and the process returns to before S61.

Next, with reference to FIG. 14, the details of the "method for estimating power supply temperature at next startup" in S61 will be described. For example, the power supply temperature estimating unit 88 estimates the power supply temperature at the time of next activation from the power supply temperature at the time of ready-off, the parking time, the average temperature of the parking place, and the like when the vehicle is parked. More specifically, the following methods are mentioned. Regarding the calculation method of [1], substep numbers from [S61-1] to [S61-6] are attached to each step.

[1] Method for calculating predicted power supply temperature using navigation information and driving history [S61-1]: Power supply temperature at parking start time Tb(0), parking start time t0
The current power supply temperature (for example, the lowest temperature of the power supply cell) is acquired as the parking start power supply temperature Tb(0). At the same time, the current time is acquired as the parking start time t0.

[S61-2]: Running start time tr
Assuming commuting and leisure, the next travel start time tr is acquired based on the history of travel start times for each day of the week.

[S61-3]: Expected temperature for each time zone Based on the GPS information, the expected temperature is acquired based on the weather forecast information or the average temperature of the parking position. For example, the expected temperature is obtained for each time period of about one week.

[S61-4]: Time Width of Time Zone of Expected Temperature The period from the parking start time t0 to the running start time tr is divided into several intervals, and the time span of the expected temperature is set. In the example of FIG. 14, time widths τ1 to τ4 are set.

[S61-5]: Estimated power supply temperature Tb(r) at next start of running
In the period from the parking start time t0 to the driving start time tr, the power supply temperature Tb(0) at the start of parking is set as an initial value, and the predicted power supply temperature Tb(r) is calculated based on the predicted air temperature for each time period and the duration thereof. Calculated. For this calculation, a heat transfer difference formula relating to the cooling of the power supply in a standing state, a map created from experimental data obtained in advance, and the like are used.

[S61-6]: Determination of Predicted Power Supply Temperature Finally, the power supply temperature and time when the IG switch is turned off are used for determination. In the example shown in FIG. 14, the predicted power source temperature Tb(r) at the running start time tr is lower than the low temperature determination value Tb _chg .

[2] Calculation of Expected Air Temperature The power supply temperature estimating unit 88 may (a) use a car navigation system to acquire the expected temperature based on the weather information for the day as the “measurement of the expected temperature” by communication. (b) It is also possible to measure and record the temperature for each time period in the most recent week, and use the minimum temperature for each time period as the expected temperature for each time period. (c) The air temperature may be obtained by taking advantage of the cell voltage equalization process of the parked Li battery. In addition, the power source temperature estimating unit 88 may simply acquire the (d) expected temperature for each night time zone as the average temperature or minimum temperature for the night as the “simplified calculation of the expected temperature”. (e) The date and time may be acquired, and the season and monthly temperature may be referenced to simply determine whether charging is possible.

[3] Calculation of predicted power supply temperature Tb(r) [3-1] Power supply temperature estimating unit 88 uses the simplified heat transfer difference formula around the power supply shown in formula (1), and starts running from parking start time t0. Predicted power supply temperature Tb(r) may be calculated by loop calculation up to start time tr. By using the heat transfer difference formula of the simple model, it becomes easy to implement it in the system. Note that the power supply temperature estimator 88 may configure a detailed heat transfer model around the power supply to calculate the predicted power supply temperature Tb(r).

Tb(t+Δt)
=Tb(t)-α(Tb(t)-Ta(t))+β(Ib(t)) ² (1)
Tb(t): Power supply temperature [°C] (initial value = Tb(0))
Ta(t): Expected temperature for each time period [°C]
Ib(t): current [A]
t: time [s], Δt: time width [s],
α, β: Coefficient

[3-2] The power supply temperature estimating unit 88 acquires the power supply temperature and the time before the start of running for the most recent one week, records it in the power supply control device 806, and calculates the lowest power supply temperature next time according to the next running start time tr. It may be the predicted power source temperature Tb(r) at the time tr when the vehicle starts running.

[3-3] Depending on the heat retention performance of the power supply, it is considered that leaving the power supply to stand overnight will cause the power supply to generally dissipate heat and cool the power supply temperature to near the expected air temperature. Therefore, it may be assumed that the predicted power supply temperature Tb(r) is the same as the predicted air temperature. Even if the power supply does not completely dissipate heat and the power supply temperature does not drop to the expected temperature, assuming that the predicted power supply temperature is the expected temperature, the setting will be on the safe side to encourage charging, so there is no problem.

Next, with reference to FIG. 15, the details of the "low temperature determination method at next start-up" in S62 will be described.

[1] Calculation of low temperature determination value [1-1] Calculation method based on required power Variables that determine the output power of a capacitive power supply include power supply temperature, SOC, and degree of deterioration (resistance increase rate). Generally, these power supply characteristic values are stored as map values inside the power supply control device 806 and are constantly calculated. Assuming that the temperature of the power supply is Tb, the SOC is θ, and the degree of deterioration (rate of resistance increase) is K, the output power P _out of the power supply is expressed as a function of these variables, as shown in Equation (2.1). .
P _out =f(Tb, θ, K) (2.1)

The power supply temperature estimator 88 first sets the required output power P _chg of the capacitive power supply required for charging between power supplies. Then, the required output power, the SOC, and the degree of deterioration are substituted into equation (2.1) to calculate the power supply temperature Tb at which the required output power P _chg can be achieved, and the lowest power supply temperature among them is taken as the low temperature determination value Tb _chg . That is, when the formula (2.2) holds, the low temperature determination value Tb _chg is calculated by the formula (2.3). The low temperature determination value Tb _chg calculated by this method is the power supply temperature when the temperature-power characteristic line of the power supply (Li battery) crosses the required output power P _chg , as shown in (*1) in FIG. .
P _max =f(Tb, θ, K)≧P _chg (2.2)
Tb _chg =Min(Tb _chg , Tb) (2.3)

[1-2] Calculation Method Based on Charging Efficiency At low temperatures, the internal resistance of the power source (that is, the Li battery) increases and Joule loss increases. Therefore, as indicated by (*2) in FIG. 15, the power supply temperature at which the charging efficiency begins to decrease due to an increase in internal resistance may be set as the low temperature determination value Tb _chg .

[2] Low temperature determination method When the predicted power supply temperature Tb(r) is equal to or lower than the low temperature determination value Tb _chg , the power supply temperature estimator 88 determines that the power supply temperature will be lower than the low temperature determination value Tb _chg when the vehicle starts running next time. Allow charging between sources.

FIG. 16 shows charging control according to the sixth embodiment. In FIG. 16, the predicted power supply temperature on the second stage is added to FIG. Since the predicted power source temperature Tb(r) at time ts1 is lower than the low temperature determination value Tb _chg , it is estimated that the second power source 30 will be in a low temperature state when the vehicle starts running next time. Therefore, after time ts1, the supplementary charging process is started in the same manner as in FIG.

As described above, in the sixth embodiment, the first power source 50 is charged from the second power source 30 in preparation for the next run before the capacitive second power source 30 cools while the vehicle is left unattended. As a result, charging can be performed while the second power source 30 and the first power source 50 are warmed up after the previous run and have high performance. In addition, the power supply temperature estimating unit 88 can appropriately estimate the predicted power supply temperature at the next start of driving by using one or more of the parking start time information, travel history, navigation information, and weather information. .

Here, the power supply temperature estimator 88 may estimate the power supply temperature at the next start of running, for example, based on the temperature information of the day or month that includes the next start of running. Cost can be reduced by such simple calculation. Alternatively, the power supply temperature estimating unit 88 may store the power supply temperature and acquisition time each time the vehicle starts running, and estimate the power supply temperature at the next start of running based on the stored power supply temperature and acquisition time. . During commuting or the like, the temperature of the power supply at the start of the previous run may be stored and assumed to be the temperature at the start of the next run.

Alternatively, the power supply temperature estimator 88 may acquire temperature information or temperature-related information estimated by an external device through communication, and estimate the power supply temperature at the next start of running based on the acquired information. As a result, the load on the power control device 806 can be reduced. Also, since the calculation method can be updated, a more accurate power supply temperature can be obtained.

(Other embodiments)
(a) The output-type first power supply 50 and the capacitive-type second power supply 30 are not limited to the lithium-ion capacitors and lithium-ion batteries exemplified in the above embodiments, but also other capacitors and batteries, or power supplies other than capacitors or batteries. may be used. Also, the type of power supply, voltage, power range, etc. may be changed.

(b) The power supply control device of the present invention may be applied to a power supply system in which the second power supply 30 is not connected to the accessory system. Alternatively, the auxiliary power supply 20 and the step-down DDC 25 for auxiliary equipment may not be provided in the auxiliary equipment system, and the electric power of the second power supply 30 may be directly supplied to the auxiliary equipment load 15 .

(c) In the charging control of the above embodiment, if the first power source 50 is not in a fully charged state, the first power source 50 may be charged every time until the next running starts. Alternatively, the first power source 50 may be charged in advance only when it is possible to predict in advance that the power source will be in a low temperature state during the next run. Even in that case, a certain degree of effect can be obtained.

(d) The power supply control device of the present invention may be applied to the power supply system of an electric vehicle instead of a hybrid vehicle. In that case, the problem of preventing the engine from starting early in the hybrid vehicle may be replaced with the problem of preventing deterioration in acceleration performance, etc., and the effect of the above embodiment may be extended and applied.

As described above, the present invention is by no means limited to the above embodiments, and can be embodied in various forms without departing from the spirit of the present invention.

10 (101, 105) power supply system,
30 (capacitance type) second power supply,
40 Bi-directional DDC (power converter),
50 (output type) first power supply,
600 drive system,
65 ... MG (motor generator),
73 ... second power supply power detector, 75 ... first power supply power detector,
80, 806 ... power control device,
83... Charging determination unit, 84... Electric power converter operation unit, 87... Running state acquisition unit.

Claims (15)

A first power supply (50) mounted on a vehicle and connected to a drive system (600) that drives a motor generator (65), a second power supply (30) having a lower voltage than the first power supply, and the drive system and A power converter (40) for bi-directionally transmitting and receiving power between the first power supply and the second power supply, wherein the first power supply is an output type power supply having a larger output than the second power supply. a power supply system (10) in which the second power supply is a capacitive power supply having a larger amount of storable power than the first power supply, and a power control apparatus for controlling the operation of the power converter, ,
a running state acquisition unit (87) that acquires information about the running state of the vehicle including vehicle stop or the set running state;
The amount of charge of the first power supply detected by the first power supply power detector (75), the amount of charge of the second power supply detected by the second power supply power detector (73), and the amount of charge of the second power supply detected by the running state acquisition unit. a charge determination unit (83) for determining whether to charge the first power supply from the second power supply based on a running state or a running setting state of the vehicle;
a power converter operation unit (84) that operates the power converter according to the determination result of the charge determination unit;
has
The running state or running setting state of the vehicle is
(1) When the vehicle speed is a predetermined judgment vehicle speed or less, or when the accelerator is off,
(2) When the shift range is P range, or when the range is changed to or from P range,
(3) When the power switch is turned off,
(4) After the judgment time has passed since ready-off,
when one or more of
The charging determination unit
when the charge amount of the first power supply is less than the charge amount threshold, the power converter is operated to charge the first power supply from the second power supply;
A power supply control device that determines to stop charging from the second power supply to the first power supply when the charge amount of the first power supply is equal to or greater than the charge amount threshold. Applied to the power supply system further comprising an automatic starter (90) that automatically starts and stops the power control device,
2. The power control device according to claim 1 , wherein the automatic activation device starts and stops the charging from the second power source to the first power source while the vehicle is parked. A first power supply (50) mounted on a vehicle and connected to a drive system (600) that drives a motor generator (65), a second power supply (30) having a lower voltage than the first power supply, and the drive system and A power converter (40) for bi-directionally transmitting and receiving power between the first power supply and the second power supply, wherein the first power supply is an output type power supply having a larger output than the second power supply. a power supply system (10) in which the second power supply is a capacitive power supply having a larger amount of storable power than the first power supply, and a power control apparatus for controlling the operation of the power converter, , the power supply system further comprises an automatic starter (90) for automatically starting and stopping the power control device,
a running state acquisition unit (87) that acquires information about the running state of the vehicle including vehicle stop or the set running state;
The amount of charge of the first power supply detected by the first power supply power detector (75), the amount of charge of the second power supply detected by the second power supply power detector (73), and the amount of charge of the second power supply detected by the running state acquisition unit. a charge determination unit (83) for determining whether to charge the first power supply from the second power supply based on a running state or a running setting state of the vehicle;
a power converter operation unit (84) that operates the power converter according to the determination result of the charge determination unit;
has
When the vehicle is in a predetermined running state or running setting state,
The charging determination unit
when the charge amount of the first power supply is less than the charge amount threshold, the power converter is operated to charge the first power supply from the second power supply;
determining to stop charging from the second power supply to the first power supply when the charge amount of the first power supply is equal to or greater than the charge amount threshold ;
A power control device that is activated and stopped by the automatic activation device while the vehicle is parked, and performs and stops charging from the second power source to the first power source . A first power source (50) mounted on a vehicle and connected to a drive system (600) that drives a motor generator (65), a second power source (30) having a lower voltage than the first power source , the drive system, and the a power converter (40) for bi-directionally transmitting and receiving power between a first power supply and the second power supply; an auxiliary power supply (20) for supplying power to an auxiliary load (15) of the vehicle; An accessory power converter (25) for stepping down a voltage of a power source and supplying power to the accessory power source , wherein the first power source is an output type power source having a larger output than the second power source, A power supply control device that is applied to a power supply system (10) in which the second power supply is a capacitive power supply that can store a larger amount of power than the first power supply, and controls the operation of the power converter,
a running state acquisition unit (87) that acquires information about the running state of the vehicle including vehicle stop or the set running state;
The amount of charge of the first power supply detected by the first power supply power detector (75), the amount of charge of the second power supply detected by the second power supply power detector (73), and the amount of charge of the second power supply detected by the running state acquisition unit. a charge determination unit (83) for determining whether to charge the first power supply from the second power supply based on a running state or a running setting state of the vehicle;
a power converter operation unit (84) that operates the power converter according to the determination result of the charge determination unit;
has
When the vehicle is in a predetermined running state or running setting state,
The charging determination unit
when the charge amount of the first power supply is less than the charge amount threshold, the power converter is operated to charge the first power supply from the second power supply;
determining to stop charging from the second power supply to the first power supply when the charge amount of the first power supply is equal to or greater than the charge amount threshold ;
The charging determination unit further determines whether or not the second power supply should charge the first power supply or the auxiliary power supply based on the amount of charge of the auxiliary power supply detected by the auxiliary power supply power detector (72). death,
The power converter operation unit further operates the power converter for auxiliary equipment according to the determination result of the charging determination unit . 5. The power supply control device according to claim 4 , wherein the auxiliary power supply is charged from the second power supply at the same time that the first power supply is charged from the second power supply. When there is a request to charge the first power supply or the auxiliary power supply, the charge determination unit operates the power converter to charge the first power supply and the auxiliary power supply from the second power supply. determined as
6. The power supply control device according to claim 5 , wherein a determination is made to stop the operation of the power converter when charging of both the first power supply and the auxiliary power supply is completed. The power supply control device according to any one of claims 1 to 6 , wherein said first power supply is a capacitor and said second power supply is a battery. 8. The power control device according to claim 7 , applied to said power supply system, wherein said first power supply is a lithium ion capacitor and said second power supply is a lithium ion battery. The power supply control according to any one of claims 1 to 8 , wherein the charge determination unit prohibits charging from the second power supply to the first power supply when the charge amount of the second power supply is equal to or less than a predetermined value. Device. a power supply temperature estimating unit (88) for estimating a predicted power supply temperature that is a predicted temperature of the second power supply at the next start of running;
10. The power supply control device according to any one of claims 1 to 9, wherein when the predicted power supply temperature is equal to or lower than the low temperature determination value, the first power supply is charged within a predetermined period before the second power supply cools down. . The low temperature determination value is the lowest power source capable of realizing the output power required to charge the first power source, based on characteristics including at least one of the output power, charge amount, and degree of deterioration of the second power source. 11. The power control device of claim 10, set as a temperature. The power supply temperature estimator,
Parking start information including the power supply temperature and parking start time at the start of parking, driving history information used for estimating the next driving start time, navigation information indicating the parking position of the vehicle, and time zone information at the parking position using one or more of weather information, including expected temperatures,
12. The power supply control device according to claim 10, wherein the predicted power supply temperature at the start of next running is estimated based on a heat transfer difference formula or experimental data relating to cooling of the power supply under standing. The power supply temperature estimator,
13. The power supply control device according to any one of claims 10 to 12, wherein the power supply temperature at the next start of running is estimated based on the temperature information of the day or month including the next start of running. The power supply temperature estimator,
14. The method according to any one of claims 10 to 13, wherein the power source temperature and the acquired time when the vehicle starts running are stored each time, and the power source temperature at the next start of running is estimated based on the stored power source temperature and acquired time. power control unit. The power supply temperature estimator,
15. The method according to any one of claims 10 to 14, wherein temperature information or temperature-related information estimated by an external device is acquired by communication, and the power supply temperature at the next start of running is estimated based on the acquired information. Power control unit.

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