JP2012157209A - Power supply control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for ensuring appropriate power supply control in a viewpoint of energy efficiency, running performance and power supply life.SOLUTION: A power supply control device comprises a request output determination means 24 for determining a request output Pn which is requested of the whole of a lithium ion secondary battery and an electric double layer capacitor based on an operation and a running state, and a control function determination means 25 having a plurality of output limit functions ft and determining one output limit function ft, or the like. The power supply control device further comprises an output limit determination means 26 for determining the output limits Cmax, Cmin of the electric double layer capacitor based on the request output Pn, the charged state Cs of the electric double layer capacitor, and the output limit function ft, and a request output distribution means 27 for distributing the request output Pn to the lithium ion secondary battery and the electric double layer capacitor based on the request output Pn, and the output limits Cmax, Cmin of the electric double layer capacitor.

Description

  The present invention relates to a power supply control device for controlling outputs from a main power supply and an assist power supply in a vehicle.

  Conventionally, various technologies have been proposed for electric vehicles that run using an electric motor as a drive source, and lithium ion secondary batteries, fuel cells, and the like have been proposed as power sources for driving the electric motors. However, load responsiveness of these power supplies is low, and there is a drawback that the life is shortened when the output change becomes steep. Therefore, it has been proposed to use a lithium ion secondary battery or the like as the main power source, and an electric double layer capacitor having a small capacity but excellent in flashing property as a power source for assisting the main power source.

  For example, the vehicle device described in Patent Document 1 includes a large-capacity power storage device, a large-output power storage device, and a control device for adjusting the charge / discharge amount. In this vehicle device, the discharge amount adjusting means is controlled so that the large-capacity power storage device discharges the average power required for traveling to the electric motor. Then, the charge / discharge amount adjusting means is arranged so that the large output power storage device discharges the insufficient power at the time of high load including acceleration to the motor, and the surplus power at the time of light load is charged from the large capacity power storage device to the large output power storage device. Be controlled. Further, the charge / discharge amount adjusting means is controlled so as to charge the regenerative electric power during deceleration from the electric motor to the high output power storage device. According to this technology, it is possible to suppress the deterioration of the power source regardless of whether the power consumption fluctuates, and it is possible to extend the life of the power source.

  The electric vehicle drive control device described in Patent Document 2 includes a lithium ion secondary battery and a capacitor, and detects the remaining power of the lithium ion secondary battery and the capacitor. If the remaining amount of the capacitor has a margin, the capacitor is operated. If the remaining amount is not, the lithium ion secondary battery performs power running and regeneration. Furthermore, if the lithium ion secondary battery has no room, it is driven by the engine. In this way, it is possible to prolong the life of the lithium ion secondary battery and improve the durability by reducing the frequency of use of the lithium ion secondary battery by preferentially using the capacitor. ing.

  In the vehicle control device described in Patent Document 3, a motor for driving the vehicle, a fuel cell connected in parallel to the motor, and a capacitor are provided. A DC-DC converter whose input and output are respectively connected to the fuel cell and the capacitor, and a control means connected to at least the fuel cell, the capacitor and the DC-DC converter are provided. A vehicle speed detecting means for detecting the vehicle speed is connected to the control means, and the control means includes a voltage control unit that changes the output voltage of the DC-DC converter in accordance with the vehicle speed detected by the vehicle speed detecting means. . According to the present invention, the energy stored in the capacitor can be actively used effectively by adjusting the output voltage of the DC-DC converter according to the vehicle speed. On the other hand, the capacitor that has released the energy is immediately charged. The operation as described above compensates for the drawback of low load response of the fuel cell.

JP 2010-41847 A JP 2008-61405 A JP 2007-181328 A

  In the prior art, the life of the secondary battery is extended by preferentially using the assist power supply, but the running performance and power consumption are not considered. Further, although the driving performance is improved by charging the assist power supply in response to the acceleration request, the life of the power supply and the power consumption are not considered.

  Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide a technique capable of appropriate power control from the comprehensive viewpoints of energy efficiency, running performance, and power life. To do.

  A power supply control device according to the present invention is a power supply control device that is provided in a vehicle and controls output from a main power supply and an assist power supply, the operation detection means for detecting an operation on the vehicle, and the traveling state of the vehicle. Based on the driving state detecting means for detecting, the temperature related to the main power supply, the power state detecting means for detecting the charging state of the assist power supply, the operation and the driving state, the main power supply and the assist power supply Request output determining means for determining a request output required for the entirety. And a plurality of output limiting functions, a plurality of target charge state functions, and a plurality of charge / discharge power functions, and from each of these functions, one output limit function, one target charge state function, and An output limit for determining the output limit of the assist power source based on the control function determining means for determining each of the charge / discharge power functions, the required output, the charge state of the assist power source, and the output limit function Based on the determining means, the required output, and the output limit of the assist power supply, the required output distribution means for distributing the required output to the main power supply and the assist power supply, the running state, and the one target And a target charge state determining means for determining a target charge state of the assist power source based on a charge state function. And charge / discharge power determination means for determining charge / discharge power between the main power supply and the assist power supply based on the charge state, the target charge state, and the one charge / discharge power function, A power output determination means for determining outputs of the main power and the assist power based on charge / discharge power, the required output allocated to the main power, and the required output allocated to the assist power; Power output control means for controlling the outputs of the main power and the assist power based on the outputs of the main power and the assist power determined by the power output determining means. The control function determining means obtains power consumption, shortage power and power supply deterioration value, and applies a weighting factor to each of the power consumption, shortage power and power supply deterioration value, and obtains an evaluation value obtained by summing them. The one output limiting function, the one target charge state function, and the one charge / discharge power function are each determined so that the evaluation value falls within a predetermined range.

  According to the present invention, the output limit of the assist power source is determined based on the requested output, the charge state of the assist power source, and the output limit function. Thereby, it is possible to suppress the life of the main power source from being shortened and to suppress a decrease in energy efficiency. Moreover, based on the evaluation value obtained by multiplying each of the power consumption, the shortage power and the power supply deterioration value by a predetermined weighting coefficient, and summing them, the output limiting function, the target charge state function, and the charge / discharge power function To decide. Therefore, appropriate power control can be performed from the comprehensive viewpoint of energy efficiency, running performance, and power source life.

It is a schematic diagram which shows a vehicle provided with a power supply control device. 1 is a block diagram illustrating a configuration of a power supply control device according to a first embodiment. FIG. 3 is a flowchart showing an operation of the power supply control apparatus according to the first embodiment. It is a figure which shows the example of a capacitor output limiting function. It is a figure for demonstrating the operation | movement which determines a secondary battery distribution output and a capacitor distribution output. It is a figure which shows a target charge condition function. It is a figure for demonstrating the operation | movement which determines an output limiting function. It is a figure for demonstrating the operation | movement which determines a target charge condition function. It is a figure for demonstrating the operation | movement which determines a charging / discharging electric power function. FIG. 4 is a block diagram showing a configuration of a power supply control device according to a second embodiment. FIG. 10 is a diagram showing a table used in the power supply control device according to the second embodiment.

<Embodiment 1>
1 is a schematic diagram showing a configuration of a drive system of a vehicle including a power supply control device according to Embodiment 1 of the present invention. The configuration of the drive system of this vehicle includes a drive wheel 1, a drive shaft 2, a speed reducer 3, an electric motor 4, an inverter 5, a power supply control device 6, a lithium ion secondary battery 7, and a DC-DC. A converter 8, an electric double layer capacitor 9, and an electric load unit 10 are provided. The vehicle is provided with a control unit (not shown) that comprehensively controls each component of the vehicle, which includes, for example, a CPU (Central Processing Unit) and a storage device.

  The lithium ion secondary battery 7 generally has an advantage of high energy density. However, the lithium ion secondary battery 7 has the property that the output decreases in a low temperature environment, and the energy loss is proportional to the square of the current value, so the energy increases as the output current increases. It has the property of reducing efficiency. Further, when the output change becomes steep, the life is shortened as a result of a decrease in capacitance or an increase in internal resistance. Therefore, in this vehicle, the lithium ion secondary battery 7 is used as the main power supply, while the electric double layer capacitor 9 that is resistant to a low temperature environment and a sharp output change assists the main power supply. It is used as

  In this vehicle, the electric motor 4 generates a driving force using outputs from the lithium ion secondary battery 7 and the electric double layer capacitor 9, and can travel by the driving force. At this time, the power supply control device 6 according to the present embodiment appropriately controls the outputs of the lithium ion secondary battery 7 and the electric double layer capacitor 9 from the viewpoints of energy efficiency, running performance, and power supply life. This will be described in detail later.

  Next, each component of such a vehicle will be described. The drive shaft 2 is fixed to the drive wheel 1. The speed reducer 3 is connected to a rotating shaft (not shown) that is rotated by the driving force of the electric motor 4, and rotates the drive shaft 2 at a rotation speed slower than the rotation of the rotating shaft. Thereby, the rotation of the electric motor 4 can be transmitted to the drive shaft 2 via the rotating shaft and the speed reducer 3. In contrast to this transmission direction, the rotation of the drive shaft 2 can be transmitted to the electric motor 4 via the speed reducer 3 and the rotation shaft.

  Here, an operation for generating a driving force when the vehicle accelerates (hereinafter, this operation may be referred to as “powering”) will be described. In this operation, each of the lithium ion secondary battery 7 and the electric double layer capacitor 9 is discharged, and a direct current generated thereby is output to the inverter 5 via the power supply control device 6. The inverter 5 converts the direct current from the lithium ion secondary battery 7 into an alternating current and supplies the alternating current to the electric motor 4. The inverter 5 converts the direct current from the electric double layer capacitor 9 into an alternating current and supplies the alternating current to the electric motor 4. When an alternating current is supplied from the inverter 5 to the electric motor 4, the rotating shaft described above is rotated by the driving force of the electric motor 4 and the vehicle is accelerated.

  Next, an operation in which the vehicle converts its own kinetic energy into electric power and charges the electric power (hereinafter, this operation may be referred to as “regeneration”) will be described. In this operation, the electric motor 4 receives the rotational energy of the rotating shaft described above and generates electric power to generate an alternating current. The inverter 5 converts the alternating current into a direct current. When a direct current is supplied from the inverter 5 to the lithium ion secondary battery 7 through the power supply control device 6, the lithium ion secondary battery 7 is charged. When a direct current is supplied from the inverter 5 to the electric double layer capacitor 9 via the power supply control device 6 and the DC-DC converter 8, the electric double layer capacitor 9 is charged.

  When the electric double layer capacitor 9 is discharged, the DC-DC converter 8 boosts the voltage from the electric double layer capacitor 9 and outputs the boosted voltage to the power supply control device 6. On the other hand, when the electric double layer capacitor 9 is charged, the DC-DC converter 8 steps down the voltage from the power supply control device 6 and outputs the stepped down voltage to the electric double layer capacitor 9.

  The electric load unit 10 is a device or component included in all electric loads used in vehicles, and is, for example, lights such as headlights, air conditioning, audio equipment, video equipment, room lighting, and wipers. The electric load unit 10 operates using the power of the lithium ion secondary battery 7.

  FIG. 2 is a block diagram showing the configuration of the power supply control device 6 that controls the outputs of the lithium ion secondary battery 7 and the electric double layer capacitor 9. As shown in the figure, the power supply control device 6 includes an operation detection means 21, a running state detection means 22, a power supply state detection means 23, a required output determination means 24, a control function determination means 25, and an output restriction determination means 26. A required output distribution means 27, a target charge state determination means 28, a charge / discharge power determination means 29, a power output determination means 30, and a power output control means 31. The required output determining means 24, the output restriction determining means 26, the required output distributing means 27, the target charge state determining means 28, the charge / discharge power determining means 29, and the power output determining means 30 are such that the above-described control unit executes an operation program. Is formed as a functional block. Hereinafter, each component of the power supply control device 6 will be described.

  The operation detection means 21 is composed of, for example, a sensor and detects the accelerator operation amount Ac and the brake operation amount Bc based on the depression amount of the accelerator pedal and the depression amount of the brake pedal. Hereinafter, the accelerator operation amount Ac and the brake operation amount Bc, which are operations related to traveling performed on the vehicle, may be collectively referred to as “traveling operations (Ac, Bc)”. The operation detection unit 21 outputs the detected traveling operation (Ac, Bc) to the request output determination unit 24.

  The traveling state detection means 22 is composed of, for example, a vehicle speed sensor and a gradient sensor, and detects the vehicle speed v of the vehicle and the gradient θ of the road on which the vehicle is traveling. Hereinafter, the vehicle speed v and the gradient θ of the vehicle may be collectively referred to as “running state (v, θ)”. The traveling state detection unit 22 outputs the detected traveling state (v, θ) to the request output determination unit 24 and the target charging state determination unit 28.

  The power supply state detection means 23 includes, for example, a temperature sensor, a charge state detection sensor, and the like. The temperature related to the lithium ion secondary battery 7 (hereinafter referred to as “secondary battery temperature Tb”) and the electric double layer capacitor 9 Is detected (hereinafter referred to as “capacitor charge state Cs”). Here, the secondary battery temperature Tb means the temperature of the lithium ion secondary battery 7 itself or the temperature around the lithium ion secondary battery 7, and the capacitor charge state Cs is charged in the electric double layer capacitor 9. The power is substantially the same. Hereinafter, the secondary battery temperature Tb and the capacitor charge state Cs may be collectively referred to as “power supply state (Tb, Cs)”. The power supply state detection unit 23 outputs the detected power supply state (Tb, Cs) to the output restriction determination unit 26, the target charge state determination unit 28 and the charge / discharge power determination unit 29.

  The requested output determining means 24 is a travel desired by the driver based on vehicle characteristic information indicating known characteristics of the vehicle such as the travel operation (Ac, Bc), the travel state (v, θ), and the vehicle weight M. Determine the output required to be done. In other words, the required output determination means 24 is based on the travel operation (Ac, Bc), the travel state (v, θ), and the vehicle characteristic information, and the entire lithium ion secondary battery 7 and the electric double layer capacitor 9. The output relating to the vehicle travel (hereinafter referred to as “request output Pn”) required is determined.

  The output restriction determination unit 26 determines a capacitor output restriction (Cmax, Cmin) indicating an output restriction (output restriction) in the electric double layer capacitor 9 based on the required output Pn, the capacitor charge state Cs, and the like. Here, Cmax indicates a limit of powering output, and Cmin indicates a limit of regenerative output.

  In the present embodiment, when the required output Pn is a power running output and the capacitor charge state Cs is high, the capacitor output limit Cmax with a weak power running output limit is determined, and conversely, the capacitor charge state Cs is low. In this case, a capacitor output limit Cmax that strongly limits the power running output is determined. On the other hand, when the required output Pn is a regenerative output, if the capacitor charge state Cs is high, a capacitor output limit Cmin that strongly restricts the regenerative output is determined. Conversely, if the capacitor charge state Cs is low, A capacitor output limit Cmin having a weak regenerative output limit is determined. This will be described in detail later. It is assumed that the conversion efficiency of the DC-DC converter 8 is taken into account in determining the capacitor output limit (Cmax, Cmin).

  The required output distribution means 27 is input with known output constraint information including secondary battery output limits (Lmin, Lmax) indicating output limits in the lithium ion secondary battery 7. Here, Lmax indicates the output limit of the lithium ion secondary battery 7 during powering output, and Lmin indicates the output limit of the lithium ion secondary battery 7 during regenerative output. In the present embodiment, the secondary battery output limit (Lmin, Lmax) is assigned to the required output Pn as much as possible among the secondary battery outputs while taking into account the electrical load required by the electrical load unit 10. Represents a value that can be

  The required output distribution unit 27 converts the required output Pn into the lithium ion secondary based on the secondary battery output limit (Lmin, Lmax) and the capacitor output limit (Cmax, Cmin) determined by the output limit determination unit 26. The secondary battery 7 and the electric double layer capacitor 9 are distributed. Hereinafter, the required output Pn distributed to the lithium ion secondary battery 7 is referred to as “secondary battery distributed output Ln”, and the required output Pn allocated to the electric double layer capacitor 9 is referred to as “capacitor distributed output Cn”. .

  The required output distribution means 27 according to the present embodiment first determines the capacitor distribution output Cn based on the capacitor output limit (Cmin, Cmax), and then determines the second output based on the secondary battery output limit (Lmin, Lmax). Next battery distribution output Ln is determined. Although details will be described later, according to such output distribution, even if the output change in the required output Pn, the output of the electric double layer capacitor 9 changes, but the output change in the lithium ion secondary battery 7 is suppressed. The Note that the capacitor distribution output Cn is not an output required for the electric double layer capacitor 9 itself but an output required for a portion constituted by the DC-DC converter 8 and the electric double layer capacitor 9.

  The target charging state determining means 28 is configured to select an appropriate target charging state (hereinafter referred to as “capacitor target charging”) to be charged in the electric double layer capacitor 9 based on the running state (v, θ), the secondary battery temperature Tb, and the like. Called state Cp). As will be described later, when the capacitor state of charge Cs matches the capacitor target state of charge Cp, power shortage is suppressed, driving performance is improved, and energy efficiency is improved. Therefore, charging / discharging is performed between the lithium ion secondary battery 7 and the electric double layer capacitor 9 so that the capacitor charging state Cs matches the capacitor target charging state Cp as much as possible. The charge / discharge power determination means 29 determines the power to be charged / discharged at this time (hereinafter referred to as “charge / discharge power Pe”) based on the capacitor target charge state Cp, the capacitor charge state Cs, and the like.

  The power supply output determining means 30 determines the secondary battery output Lm that the lithium ion secondary battery 7 should actually output based on the charge / discharge power Pe and the secondary battery distribution output Ln. Moreover, the power supply output determination means 30 determines the capacitor output Cm that the electric double layer capacitor 9 should actually output based on the charge / discharge power Pe and the capacitor distribution output Cn.

  The power supply output control means 31 is composed of, for example, a relay having a plurality of switches, and controls the output of the lithium ion secondary battery 7 based on the secondary battery output Lm, and the electric power output based on the capacitor output Cm. The output of the multilayer capacitor 9 is controlled.

  The control function determining means 25 is composed of various sensors and functional blocks formed by the above-described control unit executing an operation program. In the control function determination unit 25, a plurality of output restriction functions ft, a plurality of target charge state functions fp, and a plurality of charge / discharge power functions fe are prepared in advance.

  The control function determining means 25 is configured to output one output limit function ft, one target charge state function fp, and one charge / discharge from a plurality of output limit functions ft, a plurality of target charge state functions fp, and a plurality of charge / discharge power functions fe. Each of the power functions fe is determined. The determination by the control function determining means will be described in detail later. The control function determining means 25 outputs the determined one output limiting function ft, one target charging state function fp and one charging / discharging power function fe to the output limiting determining means 26, the target charging state determining means 28 and the charging / discharging power. Each is given to the determination means 29.

  The output limit determining unit 26 described above sets the capacitor output limit (Cmax, Cmin) based on the required output Pn and the capacitor charge state Cs and the one output limit function ft most recently given from the control function determining unit 25. decide. The target charge state determination means 28 is based on the running state (v, θ) and the secondary battery temperature Tb and the one target charge state function fp most recently given from the control function determination means 25, and the capacitor target charge state. Cp is determined. The charge / discharge power determining means 29 determines the charge / discharge power Pe based on the capacitor target charge state Cp and the capacitor charge state Cs and the one charge / discharge power function fe most recently given from the control function determining means 25. .

  Hereinafter, the plurality of output restriction functions ft, the plurality of target charge state functions fp, and the plurality of charge / discharge power functions fe may be collectively referred to as “three types of function groups”. Further, one output restriction function ft given to the output restriction determination means 26, one target charge state function fp given to the target charge state determination means 28, and one given to the charge / discharge power determination means 29. The charge / discharge power function fe may be collectively referred to as “three types of functions”.

  FIG. 3 is a flowchart showing the operation of the power supply control device 6 shown in FIG. Hereinafter, the operation of the power supply control device 6 will be described with reference to FIG. In the following expression, a positive value means discharging, and a negative value means charging.

  First, in step s1, the operation detection means 21 detects a driving operation (Ac, Bc) from the driver's accelerator operation and brake operation. Next, in step s2, the traveling state detection means 22 detects the traveling state (v, θ). Then, in step s3, the power supply state detection unit 23 detects the power supply state (Tb, Cs).

In step s4, the requested output determining means 24 determines the requested output Pn based on the traveling operation (Ac, Bc), the traveling state (v, θ), and the information feature information. In step s4, the required output determining means 24 first calculates the acceleration a necessary for the driver to perform the desired travel based on the travel operation (Ac, Bc) and the travel state (v, θ) as follows: Calculated according to (1).
a (t) = fa (Ac (t), Bc (t), v (t), θ (t)) (1)
Here, a (t), Ac (t), Bc (t), v (t) and θ (t) are acceleration a, accelerator operation amount Ac, brake operation amount Bc, vehicle speed v, The gradient θ is shown.

  fa is a function for calculating the acceleration a from the accelerator operation amount Ac, the brake operation amount Bc, the vehicle speed v, and the gradient θ. When the accelerator operation amount Ac increases, fa increases, but the brake operation amount When Bc increases, fa decreases. When the vehicle speed v takes a value close to 0, fa increases, but when the vehicle speed v takes a value far from 0, fa decreases. When the slope θ is a positive value (the vehicle is traveling uphill), fa tends to take a negative value, but the gradient θ is a negative value (the vehicle is traveling downhill). ), Fa tends to take a positive value.

After the acceleration a is calculated, the required output determination unit 24 calculates the total resistance R when the vehicle travels based on the vehicle characteristic information by the following equations (2) to (6). The required output determining means 24 according to the present embodiment includes the vehicle weight M, the CD (Constant Drag) value λ, the vehicle front projection area S, the rolling resistance coefficient μ, and the rotating part as known vehicle feature information. Inertia equivalent weight ΔM is given.
R (t) = Ra (t) + Rr (t) + Re (t) + Rc (t) (2)
Ra (t) = λ × S × v ² (t) (3)
Rr (t) = μ × M (4)
Re (t) = M × sin θ (t) (5)
Rc (t) = a (t) × (M + ΔM) / g (6)
Here, R (t), Ra (t), Rr (t), Re (t), and Rc (t) indicate total resistance, air resistance, rolling resistance, gradient resistance, and acceleration resistance at time t, respectively. , G indicates weight acceleration.

Then, the required output determining means 24 calculates the propulsive force Fn required for the vehicle to accelerate at the acceleration a (t) under the condition of the total resistance R (t) by the following equation (7), and the propulsive force Fn The required output Pn required for realizing is calculated by the following equation (8).
Fn (t) = M × a (t) + R (t) (7)
Pn (t) = Fn (t) × v (t) (8)
Here, Fn (t) and Pn (t) indicate the propulsive force Fn and the required output Pn at time t, respectively. As described above, the required output Pn is obtained in the required output determining means 24.

  When the vehicle is to be accelerated (a (t)> 0), that is, when powering is to be performed, the required output Pn takes a positive value and the vehicle is to be decelerated (a (t) <0). That is, when the regeneration is to be performed, the required output Pn takes a negative value.

  In step s5, the control function determination unit 25 determines three types of functions from the three types of function groups. Details of this operation will be described later.

In step s6, the output limit determining means 26 calculates the capacitor output limit (Cmax, Cmin) based on the sign (positive or negative) of the required output Pn, the capacitor charge state Cs, and one output limit function ft as follows: Determined by (9) and (10). However, it is assumed that the conversion efficiency of the DC-DC converter 8 is considered in the determination of the capacitor output limit (Cmax, Cmin).
When powering (Pn (t)> 0): Cmax (t) = ft (Cs (t)) (9)
In the case of regeneration (Pn (t) <0): Cmin (t) = ft (Cs (t)) − ft (1) (10)
In equations (9) and (10), Cs (t) is standardized so that 0 ≦ Cs (t) ≦ 1, and ft (1) has the largest Cs (t). Means the value of ft. In this description, the expressions for powering and regeneration are represented by the same output limiting function ft, but different output limiting functions may be used for powering and regeneration.

  FIG. 4 is a diagram illustrating an example of the output restriction function ft. When the required output Pn (t) is power running (the upper diagram in FIG. 4), when the capacitor charge state Cs (t) is high (that is, the electric double layer capacitor 9 is sufficiently charged), In order to use the electric power in the double layer capacitor 9 as much as possible, the capacitor output limit Cmax whose power output limit is weak (absolute value is large) is determined. Similarly, in the case where the required output Pn (t) is also power running, when the capacitor charge state Cs (t) is low (that is, the electric double layer capacitor 9 is hardly charged), the electric double layer capacitor 9 In order to prevent the electric power from being used any more, the capacitor output limit Cmax having a strong power running output limit (small absolute value) is determined.

  On the other hand, when the required output Pn (t) is regenerative (the lower diagram in FIG. 4), the capacitor charge state Cs (t) is high (that is, the electric double layer capacitor 9 is sufficiently charged). In order to prevent the electric double layer capacitor 9 from being charged any more, a capacitor output limit Cmin with a strong regenerative output limit (small absolute value) is determined. Similarly, when the required output Pn (t) is regenerative and the capacitor charge state Cs (t) is low (that is, the electric double layer capacitor 9 is hardly charged), the electric double layer capacitor 9 is In order to charge as much as possible, the capacitor output limit Cmin with a weak regenerative output limit (large absolute value) is determined.

  According to the power supply control device 6 according to the present embodiment, when the electric double layer capacitor 9 has a margin, the electric double layer capacitor 9 tries to perform power running and regeneration as much as possible. As a result, since a sharp change in output in the lithium ion secondary battery 7 can be suppressed, the life of the lithium ion secondary battery 7 can be suppressed from being shortened. Moreover, since it can also be expected to suppress an increase in the output of the lithium ion secondary battery 7, it can also be expected to suppress a decrease in energy efficiency.

  On the other hand, as will be described later, when the electric double layer capacitor 9 has no margin, the output of the lithium ion secondary battery 7 is also used. Therefore, the possibility that the electric power of the vehicle is insufficient can be reduced, and the electric power obtained by converting the kinetic energy of the vehicle can be charged as much as possible, so that a decrease in energy efficiency can be suppressed.

  In step s7, the required output distribution means 27 performs the secondary battery distribution output Ln based on the required output Pn, the secondary battery output limit (Lmin, Lmax) and the capacitor output limit (Cmax, Cmin) determined in step s6. And determine the capacitor distribution output Cn.

  FIG. 5 is a diagram for explaining the operation at this step in the request output distribution means 27. On the upper side of FIG. 5, the capacitor distribution output Cn, the secondary battery distribution output Ln, and the required output Pn are shown by a solid line, a broken line, and a two-dot chain line, respectively. On the lower side of FIG. 5, the capacitor charge state Cs (t) is shown. Hereinafter, the operation in this step will be described in detail with reference to FIG.

  In the time zone T1 shown in FIG. 5, the required output Pn (t) is the powering output (Pn> 0), and the capacitor output limit Cmax (t) for limiting the powering output is equal to or greater than the required output Pn (t). Some cases are shown. In this case, the electric double layer capacitor 9 is sufficiently charged (capacitor charge state Cs is sufficiently large), and the required output Pn can be satisfied only by the powering output. Therefore, the required output distribution unit 27 determines the capacitor distribution output Cn (t) as Pn (t) and the secondary battery distribution output Ln (t) as 0.

  In the time zone T2 and the time zone T3, a case where the required output Pn (t) is a powering output (Pn> 0) and the capacitor output limit Cmax (t) is smaller than the required output Pn (t) is shown. Yes. In this case, since the required output Pn cannot be satisfied only by the power running output of the electric double layer capacitor 9, the power running output of the lithium ion secondary battery 7 is added. However, in order to perform powering in the electric double layer capacitor 9 as much as possible, the required output distribution unit 27 sets the capacitor distribution output Cn (t) to the maximum powering output allowed for the electric double layer capacitor 9. A certain capacitor output limit Cmax (t) is determined.

  Of the time zones T2 and T3, in the time zone T2, a case where the secondary battery output limit Lmax (t) for limiting the powering output is equal to or greater than Pn (t) −Cmax (t) is shown. ing. In this case, since the power output of the lithium ion secondary battery 7 and the electric double layer capacitor 9 can satisfy the required output Pn, the required output distribution means 27 sets the secondary battery distribution output Ln (t) to Pn ( t)-Cmax (t) is determined.

  On the other hand, in the time zone T3, a case where the secondary battery output limit Lmax (t) is smaller than Pn (t) −Cmax (t) is shown. In this case, in order to make the sum of the powering outputs of the lithium ion secondary battery 7 and the electric double layer capacitor 9 as close as possible to the required output Pn (t), the required output distribution means 27 includes the secondary battery. The distribution output Ln (t) is determined as Lmax (t). In this case, since the required output Pn (t) is not satisfied, the acceleration of the vehicle desired by the driver cannot be realized. In order to avoid this, it is desirable to notify the driver in advance that the remaining amount of power is low.

  In the time zone T4, the required output Pn is the regenerative output (Pn <0), and the absolute value of the capacitor output limit Cmin (t) that limits the regenerative output is greater than or equal to the absolute value of the required output Pn (t) It is shown. In this case, the electric double layer capacitor 9 is hardly charged (capacitor charge state Cs is sufficiently small), and the required output Pn can be satisfied only by the regenerative output. Therefore, the required output distribution unit 27 determines the capacitor distribution output Cn (t) as Pn (t) and the secondary battery distribution output Ln (t) as 0.

  In the time zone T5 and the time zone T6, the request output is a regenerative output (Pn <0), and the absolute value of the capacitor output limit Cmin (t) is smaller than the absolute value of the request output Pn (t). Has been. In this case, since the required output Pn cannot be satisfied only by the regenerative output of the electric double layer capacitor 9, the regenerative output of the lithium ion secondary battery 7 is added. However, in order to regenerate the electric double layer capacitor 9 as much as possible, the required output distribution means 27 sets the capacitor distribution output Cn (t) to the maximum regenerative output allowed for the electric double layer capacitor 9. A certain capacitor output limit Cmin (t) is determined.

  Of the time zones T5 and T6, in the time zone T5, the absolute value of the secondary battery output limit Lmin (t) that limits the regenerative output is (Pn (t) −Cmin (t)). The case where it is more than the value is shown. In this case, since the required output Pn can be satisfied by the regenerative outputs of the lithium ion secondary battery 7 and the electric double layer capacitor 9, the required output distribution unit 27 sets the secondary battery distribution output Ln (t) to Pn ( t) -Cmin (t).

  On the other hand, in the time zone T6, the case where the absolute value of the secondary battery output limit Lmin (t) is smaller than the absolute value of (Pn (t) −Cmin (t)) is shown. In this case, in order to make the absolute value of the sum of the regenerative outputs of the lithium ion secondary battery 7 and the electric double layer capacitor 9 as close as possible to the required output Pn (t), the required output distribution means 27 The secondary battery distribution output Ln (t) is determined as Lmin (t). In this case, since the required output Pn (t) is not satisfied, the deceleration of the vehicle desired by the driver cannot be realized. In order to avoid this, it is desirable to provide a mechanical brake as an auxiliary.

  In the distribution of the required output as described above, the required output Pn is positively distributed to the electric double layer capacitor 9. That is, the distribution of the required output Pn to the lithium ion secondary battery 7 is suppressed. Here, as described above, in the lithium ion secondary battery 7, energy loss occurs in proportion to the square of the current value. According to such distribution, the lithium ion secondary battery 7 is required. Since the output Pn is suppressed, energy loss can be reduced, and improvement in energy efficiency can be expected. Further, according to this distribution, since a rapid output change in the lithium ion secondary battery 7 that causes deterioration of the lithium ion secondary battery 7 is suppressed, the deterioration of the lithium ion secondary battery 7 is suppressed. Can be expected.

Now, referring back to FIG. 3, in step s8, the target charge state determination means 28 determines the capacitor target based on the running state (v, θ), the secondary battery temperature Tb, and the one target charge state function fp. The state of charge Cp is obtained by the following equation (11).
Cp (t) = fp (v (t), θ (t), Tb (t)) (11)
Here, Cp (t) indicates the capacitor target charge state Cp at time t. As is clear from the equation (11), the target charge state function fp is a function of the running state (v, θ) and the secondary battery temperature Tb that indicates the capacitor target charge state Cp.

  FIG. 6 is a diagram showing a target charge state function fp according to the present embodiment. In this target charge state function fp, the capacitor target charge state Cp is increased when the vehicle speed is low, that is, the vehicle speed v is low, and the capacitor target charge state Cp is decreased when the vehicle speed is high, that is, the vehicle speed v is large. ing.

  As described above, by charging / discharging between the lithium ion secondary battery 7 and the electric double layer capacitor 9, the capacitor charge state Cs is controlled to be as close as possible to the capacitor target charge state Cp. Therefore, when the vehicle travels at a low speed at which acceleration is likely to be requested, the capacitor charge state Cs is sufficiently high as well as the capacitor target charge state Cp, so that the vehicle speed v is temporarily increased. Even if acceleration is required, it is possible to suppress the occurrence of power shortage in the electric double layer capacitor 9. Therefore, traveling performance can be improved. On the other hand, when the vehicle travels at a high speed that is likely to require deceleration, the capacitor charge state Cs as well as the capacitor target charge state Cp are sufficiently low, so that the energy during regeneration is efficiently recovered. can do.

  In the present embodiment, the capacitor target charge state Cp indicated by the target charge state function fp is changed not only by the vehicle speed v but also by the gradient θ and the secondary battery temperature Tb.

  Specifically, in the target charge state function fp according to the present embodiment, when the gradient θ indicates an uphill, the capacitor target charge state Cp is increased, and when the gradient θ indicates a downhill, The capacitor target charge state Cp is made low. As a result, when the vehicle travels on an uphill where there is a high possibility of requesting acceleration, the capacitor charge state Cs is sufficiently high, so even if acceleration is required to increase the vehicle speed v Further, it is possible to suppress the occurrence of power shortage in the electric double layer capacitor 9. On the other hand, when the vehicle travels on a downhill where there is a high possibility of a request for deceleration, the capacitor charge state Cs is sufficiently low, so that energy during regeneration can be efficiently recovered.

  In addition, since the lithium ion secondary battery 7 tends to have low operating performance at low temperatures, it is considered that the output is somewhat insufficient at low temperatures. Therefore, when the secondary battery temperature Tb is low, if the electric double layer capacitor 9 actively outputs so as to compensate for the decrease in the operating performance of the lithium ion secondary battery 7, the output of the electric double layer capacitor 9 is insufficient. Can be expected to avoid. Specifically, in the target charge state function fp, as shown in FIG. 6, when the secondary battery temperature Tb is low, the capacitor target charge state Cp is set high. Thereby, the output shortage at the time of low temperature can be suppressed reliably.

Returning to FIG. 3, in step s9, the charge / discharge power determination means 29 has the capacitor charge state Cs, the capacitor target charge state Cp, the secondary battery output limit (Lmin, Lmax), and the capacitor output limit determined in step s6 ( Cmin, Cmax) and one charge / discharge power function fe, charge / discharge power Pe to be charged / discharged between the lithium ion secondary battery 7 and the electric double layer capacitor 9 is obtained by the following equation (12). .
Pe (t) = fe (Cp (t), Cs (t)) (12)
Here, Pe (t) represents the charge / discharge power Pe at time t. As is clear from the equation (12), the charge / discharge power function fe is a function of the capacitor charge state Cs and the capacitor target charge state Cp indicating the charge / discharge power Pe.

  If the charge / discharge power Pe is positive, it means that the lithium ion secondary battery 7 is discharged. In this case, the electric double layer capacitor 9 is charged with the electric power of the lithium ion secondary battery 7. On the other hand, if the charge / discharge power Pe is negative, it means that the lithium ion secondary battery 7 is charged. In this case, the electric power of the electric double layer capacitor 9 is charged to the lithium ion secondary battery 7.

  However, when Pe (t) is positive, the output limits of the lithium ion secondary battery 7 and the electric double layer capacitor 9 (that is, Lmax (t), Cmax (t)) are considered, and Lmax (t) −Ln ( The smaller one of t) and-(Cmin (t) -Cn (t)) is defined as the charge / discharge power upper limit value Pemax (t). That is, when Pe (t) is larger than Pemax (t), the value of Pe (t) is set to Pemax (t). Similarly, when Pe (t) is negative, Lmin (t) −Ln is considered in consideration of output limitations (that is, Lmin (t), Cmin (t)) of the lithium ion secondary battery 7 and the electric double layer capacitor 9. The larger one (the smaller of these absolute values) of (t) and-(Cmin (t) -Cn (t)) is defined as the charge / discharge power lower limit value Pemin (t). That is, when Pe (t) is smaller than Pemin (t) (greater than the absolute value of Pemin (t)), the value of Pe (t) is set to Pemin (t).

  In step s10, the power output determining means 30 is based on the secondary battery distribution output Ln (t) and capacitor distribution output Cn (t) determined in step s7 and the charge / discharge power Pe (t) determined in step s9. Thus, the secondary battery output Lm (t) to be actually output by the lithium ion secondary battery 7 and the capacitor output Cm (t) to be actually output by the electric double layer capacitor 9 are determined.

  Here, the power output determining means 30 determines the secondary battery output Lm (t) by subtracting the charge / discharge power Pe (t) from the secondary battery distributed output Ln (t), and the capacitor distributed output Cn. A value obtained by adding charge / discharge power Pe (t) to (t) is determined as capacitor output Cm (t).

  In step s11, the power output control means 31 controls the output of the lithium ion secondary battery 7 based on the secondary battery output Lm (t), and the electric double layer capacitor 9 based on the capacitor output Cm (t). Control the output.

<Operation of control function determining means>
The operation other than step s5 has been described in detail above. Next, the operation in which the control function determination unit 25 determines three types of functions from the three types of functions in step s5 will be described. This step s5 may be performed when the vehicle travels, or may be performed when the vehicle is shipped, or when the lithium ion secondary battery 7 or the electric double layer capacitor 9 is replaced.

<Determination of output limiting function>
The control function determination unit 25 sequentially changes one output limit function ft to be given to the output limit determination unit 26 among the plurality of output limit functions ft every time the vehicle travels for a certain period of time. At this time, the control function determination unit 25 uses the target charge state determination unit 28 and the charge / discharge function as one target charge state function fp determined in advance as a default and one charge / discharge power function fe predetermined as a default. It is assumed that the power determination unit 29 is provided with each.

  Here, when the secondary battery output Lm and the capacitor output Cm are obtained in step s10 shown in FIG. 3, the output restriction function ft is added in step s6. The secondary battery output Lm and the capacitor output Cm also change. As a result, when the output restriction function ft changes, the traveling of the vehicle also changes.

  When the vehicle is running with the target charge state function fp and the charge / discharge power function fe fixed by default functions and the one output restriction function ft being changed in order, the control function determination means 25 In the following manner, “power consumption”, “insufficient power”, and “power supply degradation value” are obtained for each of the plurality of output limiting functions ft.

  First, an operation in which the control function determining unit 25 obtains “power consumption” will be described below. The control function determining means 25 according to the present embodiment measures, for example, the charging state of the lithium ion secondary battery 7 and the capacitor charging state Cs, and when the vehicle actually travels based on these charging states. Get the actual energy (power) consumed. In parallel with this, the control function determining means 25 calculates the energy of prediction predicted to be necessary for the vehicle to realize its travel. Then, the control function determining means 25 obtains (predicted energy) / (actual energy) as energy efficiency.

  Here, the control function determining unit 25 has a table in which energy efficiency and power consumption are associated one-to-one, and based on the obtained energy efficiency and the table, the power consumption is output to the output limiting function ft. Ask for each. In this table, when the energy efficiency is high (actual energy is small), the power consumption is small, and when the energy efficiency is low (actual energy is large), the power consumption is large.

  Next, an operation in which the control function determining unit 25 calculates “insufficient power” will be described. The control function determining means 25 according to the present embodiment measures, for example, the vehicle speed v, and based on the vehicle speed v, the time during which the vehicle has not been able to travel at the requested speed or a speed in the vicinity thereof (hereinafter referred to as “vehicle speed”). Called "deviation time"). Then, the control function determining means 25 obtains ((total travel time−vehicle speed deviation time) / total travel time) as the travel performance value.

  Here, the control function determination means 25 has a table in which the running performance value and the insufficient power are associated one-to-one, and the output limitation of the insufficient power is performed based on the obtained running performance value and the table. Obtained for each function ft. In this table, when the running performance value is high (vehicle speed deviation time is short), the insufficient power is small, and when the running performance value is low (vehicle speed deviation time is long), the insufficient power is large.

  Finally, an operation in which the control function determining unit 25 obtains the “power supply deterioration value” will be described. The control function determining unit 25 according to the present embodiment measures, for example, a reduction amount of the energy capacity of the lithium ion secondary battery 7. Here, the control function determining means 25 has a table in which the amount of decrease in the energy capacity of the lithium ion secondary battery 7 and the power supply deterioration value are associated one-to-one. Based on the above, the power supply deterioration value is obtained. In this table, the power supply deterioration value is high when the energy capacity decrease amount is large, and the power supply deterioration value is low when the energy capacity decrease amount is small.

  Here, the control function determination unit 25 calculates the power supply deterioration value based on the decrease amount of the energy capacity of the lithium ion secondary battery 7, but is not limited to this. The power supply deterioration value may be obtained based on the amount of increase in resistance. Specifically, the control function determination unit 25 measures, for example, an increase amount of the internal resistance. Here, the control function determining means 25 has a table in which the increase amount of the internal resistance of the lithium ion secondary battery 7 and the power supply deterioration value are associated one-to-one. Based on the above, the power supply deterioration value is obtained. In this table, the power supply deterioration value is high when the increase amount of the internal resistance is large, and the power supply deterioration value is low when the increase amount of the internal resistance is small.

  Alternatively, the control function determining unit 25 may obtain the power supply deterioration value based on the weighted sum of the decrease amount of the energy capacity and the increase amount of the internal resistance.

  As described above, the control function determining unit 25 calculates the power consumption, the insufficient power, and the power supply deterioration value for each of the plurality of output limiting functions ft. The control function determination unit 25 uses various sensors to perform measurements necessary to calculate them, and some of the various sensors include a sensor constituting the operation detection unit 21 and a traveling state detection unit. The sensor that constitutes the power source 22 and the sensor that constitutes the power supply state detection means 23 may be substituted.

FIG. 7 is a graph showing simulation results of power consumption, insufficient power, and power supply deterioration value for each output limiting characteristic coefficient α (coefficient defining the output limiting function ft). Here, in order to simplify the description, ft (Cs (t)) = the above equation (9) representing the output limit Cmax during power running and the above equation (10) representing the output limit Cmin during regeneration The functions of the following equations (13) and (14), which are α × Cs (t), are used.
Cmax (t) = α × Cs (t) (13)
Cmin (t) = α × Cs (t) −α (14)
In these equations (13) and (14), the same output limiting characteristic coefficient α is used for Cmax (t) and Cmin (t), but different output limiting characteristic coefficients are used for power running and regeneration. Also good. Since the value of the output limiting characteristic coefficient α changes when the pattern of the output limiting function ft is changed, here, the output limiting function ft will be described in place of the output limiting characteristic coefficient α. The power consumption, the shortage power, and the power supply deterioration value obtained from the simulation result are substantially the same as the power consumption, the shortage power, and the power supply deterioration value calculated by the control function determining unit 25. In FIG. 7, the power consumption, the insufficient power, and the power supply deterioration value are normalized, and are indicated by a broken line, a one-dot chain line, and a two-dot chain line, respectively. The normalized value of each item is plotted according to the value of the vertical axis on the left side of the graph.

  In FIG. 7, it is desirable that the power consumption, the insufficient power, and the power supply deterioration value are all small. However, as shown in FIG. 7, when trying to reduce the insufficient power and the power supply deterioration value, the power consumption increases.

  Therefore, the control function determining unit 25 outputs an evaluation value (evaluation value obtained by weighted sum) obtained by multiplying each of the power consumption, the insufficient power, and the power supply deterioration value by a predetermined weighting coefficient and summing them. Calculated for each limiting characteristic coefficient α. In FIG. 7, the weighted sum evaluation value is shown by a solid line in a normalized state. The evaluation value is plotted according to the value on the vertical axis on the right side of the graph. The control function determining means 25 determines one output limiting characteristic coefficient α so that the weighted evaluation value falls within a predetermined range. In the present embodiment, the control function determining means 25 determines one output limiting characteristic coefficient α whose evaluation value is smaller than the threshold value. That is, the control function determining means 25 determines one output limiting characteristic coefficient α (one output limiting function ft) appropriate from the viewpoints of energy efficiency, running performance, and power source life.

<Determination of target charge state function>
Similarly to the above, the control function determination unit 25 sequentially changes one target charge state function fp to be given to the target charge state determination unit 28 among the plurality of target charge state functions fp every time the vehicle travels for a certain period of time. I will do it. At this time, the control function determining means 25 uses the output restriction determining means 26 and the charging / discharging power determining means for the one output limiting function ft already determined in the above and the one charging / discharging power function fe determined in advance as a default. 29 is assigned to each.

  Here, when the secondary battery output Lm and the capacitor output Cm are obtained in step s10 shown in FIG. 3, since the target charge state function fp is added in step s8, the target charge state function fp changes. The traveling of the vehicle also varies depending on the target charge state function fp.

  When the vehicle is traveling in a state where the one target charging state function fp is sequentially changed, the control function determining unit 25 determines each of the power consumption, the insufficient power, and the power supply deterioration value as described above. It calculates | requires with respect to each of several target charge state function fp.

FIG. 8 is a graph showing simulation results of power consumption, insufficient power, and power supply degradation value for each target charge state characteristic coefficient β (coefficient defining the target charge state function fp), as in FIG. Here, in order to simplify the description, the following equation (15) is used as the target charge state function fp of the above equation (11) representing the capacitor target charge state Cp. The target charge state function fp is preferably a function of v (t), θ (t), and Tb (t) as shown in the above equation (11). However, for convenience of explanation, the following equation (15 The target charge state function fp indicated by () is a function of only v (t).
Cp (t) = exp (−β × v (t)) (15)
In this equation (15), as the target charge state characteristic coefficient β increases, the capacitor target charge state Cp (t) indicated by the target charge state function fp decreases.

  In FIG. 8, as the target charge state characteristic coefficient β increases, the power consumption and the power supply deterioration value do not change, but the insufficient power increases. Accordingly, the above-described weighted sum evaluation value also increases. Therefore, the control function determination unit 25 determines one target charge state function fp whose evaluation value is smaller than the threshold value. That is, the control function determining means 25 determines one target charge state function fp appropriate from the viewpoint of running performance. Here, although the power consumption and the power supply deterioration value did not change, they change when the target charge state function fp is v (t), θ (t), or Tb (t). In this case as well, if the control function determining means 25 determines one target state-of-charge function fp based on the above-mentioned weighted sum evaluation value, an appropriate one from the viewpoints of energy efficiency, running performance, and power source life. Target charge state function fp is determined.

<Determination of charge / discharge power function>
Similarly to the above, the control function determining unit 25 sequentially changes one charging / discharging power function fe provided to the charging / discharging power determining unit 29 among the plurality of charging / discharging power functions fe every time the vehicle travels for a certain period of time. I will do it. At this time, the control function determination means 25 gives the output restriction function ft and the target charge state function fp already determined in the above to the output restriction determination means 26 and the target charge state determination means 28, respectively. And

  Here, when the secondary battery output Lm and the capacitor output Cm are obtained in step s10 shown in FIG. 3, the charge / discharge power function fe is changed because the charge / discharge power function fe is added in step s9. Then, the running of the vehicle also changes depending on the charge / discharge power function fe.

  When the vehicle is traveling in a state in which one charge / discharge power function fe is sequentially changed, the control function determining unit 25 determines each of the power consumption, the insufficient power, and the power supply deterioration value in the same manner as described above. It calculates | requires with respect to each of several charging / discharging electric power function fe.

FIG. 9 is a graph showing simulation results of power consumption, insufficient power, and power supply degradation value for each charge / discharge power characteristic coefficient γ (coefficient defining charge / discharge power function fe), as in FIG. 7. Here, the following formula (16) is used as the charge / discharge power function fe of the above formula (12) representing the charge / discharge power Pe.
Pe (t) = γ × (Cp (t) −Cs (t)) (16)
In this equation (16), as the charge / discharge power characteristic coefficient γ increases, the absolute value of the charge / discharge power Pe (t) indicated by the charge / discharge power function fe increases.

  The charge / discharge power function fe shown in the equation (16) is a function of the difference between the capacitor charge state Cs and the capacitor target charge state Cp, which indicates the charge / discharge power Pe. In the charge / discharge power function fe, when the absolute value of the difference is small, the absolute value of the charge / discharge power Pe is small, and when the absolute value of the difference is large, the absolute value of the charge / discharge power Pe is large. . Therefore, according to the charge / discharge power function fe shown in Expression (16), when the absolute value of the difference is small, the absolute value of the charge / discharge power Pe can be lowered to suppress the output change of the lithium ion secondary battery 7. On the other hand, when the absolute value of the difference is large, the absolute value of the charge / discharge power Pe can be increased to improve the followability of the capacitor charge state Cs to the capacitor target charge state Cp. Therefore, the capacitor charge state Cs can be appropriately followed by the capacitor target charge state Cp.

  FIG. 9 shows that when the power consumption and the power supply deterioration value are reduced, the power shortage increases. Therefore, the control function determination unit 25 determines one charge / discharge power function fe in which the weighted evaluation value described above is smaller than the threshold value. That is, the control function determination unit 25 determines one appropriate charge / discharge power function fe from the viewpoints of energy efficiency, running performance, and power source life.

  According to the power supply control device 6 according to the present embodiment as described above, the capacitor output limit (Cmax, Cmin) is determined based on the required output Pn, the capacitor charge state Cs, and the output limit function ft. Thereby, while being able to suppress that the lifetime of the lithium ion secondary battery 7 becomes short, the fall of energy efficiency can be suppressed. In addition, one output limiting function ft, one target charge state function, based on an evaluation value obtained by multiplying each of power consumption, insufficient power, and power supply deterioration value by a predetermined weighting coefficient and summing them. fp and one charge / discharge power function fe are determined. Therefore, appropriate power control can be performed from the comprehensive viewpoint of energy efficiency, running performance, and power source life.

  In the above, in order to facilitate understanding, the control function determination means 25 selects one function from the remaining one type of function group in a state where two types of function groups are fixed out of the three types of function groups. Then, three types of functions were selected by sequentially performing this selection method on the three types of function groups. However, the present invention is not limited to this, and three types of functions may be changed simultaneously, and three types of functions may be selected from the three types of functions. In this way, since the selection range is widened, more appropriate three types of functions can be determined, and power supply control with higher satisfaction can be performed.

  In the above description, each function is defined by parameters α, β, and γ. However, the present invention is not limited to this, and each function may be defined by a plurality of parameters. Further, although the same output restriction function ft is used for power running and regeneration, the output restriction function ft is not limited to this, and different output restriction functions may be used for power running and regeneration. In this case, since the output limiting function at the time of power running and regeneration is individually changed, the above “three types of functions” become “four types of functions”. Then, it is possible to determine each function. That is, if three functions are fixed out of the four function groups, one function is selected from the remaining one function group, and this selection method is sequentially performed on the four function groups. It is possible to determine four types of functions. Alternatively, four types of functions may be changed simultaneously, and four types of functions may be selected simultaneously from the four types of functions.

  In the above description, for example, the control function determining unit 25 determines one function whose weighted evaluation value is smaller than the threshold value, but it is desirable to determine a function having the smallest evaluation value. .

  In the above description, a lithium ion secondary battery is used as the main power source and an electric double layer capacitor is used as the assist power source. However, the assist power source is more resistant to changes in output than the main power source, and between the main power source and the assist power source. If it can charge / discharge with, it will not be restricted to this. For example, a fuel cell may be used as the main power source, and a secondary battery may be used as the assist power source. In the above description, the electric vehicle driven by the electric motor 4 has been described. However, in addition to the electric vehicle, the power supply control device 6 according to the present embodiment is provided in a hybrid vehicle in which an engine and a secondary battery are combined. May be.

  In the above description, as shown in FIG. 3, the case where steps s1 to s4 and steps s6 to s11 are performed in series has been described. However, these steps may be partially performed in parallel.

  Further, as described in the description of the power supply control device 6, when the vehicle is braked, that is, when regenerative energy is generated, if it is likely that the driver will not be able to decelerate the vehicle, the shortage of the braking force is You may make it supplement with a type brake (not shown). In addition, if the vehicle according to the present embodiment is a hybrid vehicle, when the vehicle is driven, that is, when powering energy is generated, the vehicle that the driver desires cannot be accelerated. You may make it supplement with (not shown).

<Embodiment 2>
FIG. 10 is a block diagram showing a configuration of power supply control device 6 according to the present embodiment. The power supply control device 6 according to the present embodiment is the same as the power supply control device 6 described above except that the operation of the control function determination unit 25 is different and a prior information detection unit 32 is added.

  The prior information detection means 32 included in the power supply control device 6 according to the present embodiment includes, for example, a car navigation system and detects information related to a road on which the vehicle is about to travel in the near future (hereinafter referred to as “preliminary information”). To do. In the present embodiment, the prior information detection means 32 detects the gradient of the road on which the vehicle is about to travel in the near future (hereinafter referred to as “preliminary gradient θp”) as the prior information.

  Further, the control function determination unit 25 according to the present embodiment has a plurality of travel modes respectively associated with combinations of a plurality of output restriction functions ft, a plurality of target charge state functions fp, and a plurality of charge / discharge power functions fe. is doing. Hereinafter, the control function determination unit 25 according to this embodiment will be described. In the following, the output limiting function ft will be described in place of the output limiting characteristic coefficient α.

  FIG. 11 shows a table of travel modes that the control function determination means 25 has. In the table shown in FIG. 11, the driving modes are associated one-to-one with the set of the pre-gradient θp and the secondary battery temperature Tb. One driving mode corresponds to one cell in the table, and the three numbers in parentheses in the cell indicate the value of the output limiting characteristic coefficient α, the target charge state characteristic coefficient associated with the driving mode. The value of β and the value of the charge / discharge power characteristic coefficient γ are shown. For example, the travel mode of the cell described as (7, 0.01, 0.06) in the third row from the top and the second column from the left is the output limiting characteristic coefficient α having the value “7”. , The target charge state characteristic coefficient β having a value of “0.01” and the charge / discharge power characteristic coefficient γ having a value of “0.06”.

  The tendency of the output restriction characteristic coefficient α, the target charge state characteristic coefficient β, and the charge / discharge power characteristic coefficient γ will be described.

  When the pre-gradient θp indicates an uphill and the secondary battery temperature Tb indicates a low temperature, it is considered that the deterioration due to the output change of the lithium ion secondary battery 7 is relatively small. Therefore, a smaller output restriction characteristic coefficient α is assigned to the travel mode to be performed in this case than when the secondary battery temperature Tb indicates a high temperature. However, as shown in FIG. 11, the output limiting characteristic coefficient α may be constant with respect to the change in the prior gradient θp.

  Further, in order to avoid insufficient output when the above-mentioned pre-gradient θp is uphill and the secondary battery temperature Tb is low, the capacitor target charge state Cp is high for the travel mode to be performed in this case. Thus, a smaller target charge state characteristic coefficient β is assigned than when the pre-gradient θp indicates a descending plate, and the charge / discharge power characteristic coefficient γ is larger than when the pre-gradient θp indicates a descending plate so that the charge / discharge power Pe increases. Assigned.

  On the other hand, when the prior gradient θp indicates a downhill and the secondary battery temperature Tb is high, it is considered that the deterioration due to the output change of the lithium ion secondary battery 7 is relatively large. Therefore, a larger output limiting characteristic coefficient α is assigned to the travel mode to be performed in this case than when the secondary battery temperature Tb indicates a low temperature. However, as shown in FIG. 11, the output limiting characteristic coefficient α may be constant with respect to the change in the prior gradient θp.

  Further, in order to sufficiently recover the regenerative energy in the electric double layer capacitor 9 when the above-mentioned pre-gradient θp is a downhill and the secondary battery temperature Tb is high, the driving mode to be performed in this case is When the pre-gradient θp indicates a climb so that the capacitor target charge state Cp is low, a larger target charge state characteristic coefficient β is assigned, and the pre-gradient θp indicates a climb so that the charge / discharge power Pe is small A smaller charge / discharge power characteristic coefficient γ is assigned. At this time, it is desirable to assign a small charge / discharge power characteristic coefficient γ so that the charge / discharge power Pe is small. However, when the charge / discharge power Pe increases when the secondary battery temperature Tb is high, the lithium ion secondary battery The secondary battery 7 is likely to deteriorate. Therefore, a charge / discharge power characteristic coefficient γ is assigned to the traveling mode in which the secondary battery temperature Tb is high (40 ° C. or higher in FIG. 11), with the charge / discharge power Pe having a medium magnitude. For the travel mode in which the secondary battery temperature Tb is medium temperature, a large charge / discharge power characteristic coefficient γ is set so that the charge / discharge power Pe is larger than that in the travel mode in which the secondary battery temperature Tb is high. Assigned.

  The control function determination unit 25 according to the present embodiment selects one travel mode from a plurality of travel modes based on the prior gradient θp detected by the prior information detection unit 32 and the secondary battery temperature Tb. Then, the control function determining unit 25 reads the output limiting characteristic coefficient α (output limiting function ft) associated with the one traveling mode from the above table, and outputs the output limiting function ft to the output limiting determining unit 26. It is determined as one output limiting function ft to be used. Similarly, the control function determination unit 25 reads the target charge state characteristic coefficient β (target charge state function fp) associated with the one travel mode from the above table, and uses the target charge state function fp as the target charge state. It is determined as one target charge state function fp used for the state determination means 28. Similarly, the control function determining unit 25 reads the charge / discharge power characteristic coefficient γ (charge / discharge power function fe) associated with the one travel mode from the above table, and uses the charge / discharge power function fe as the charge / discharge power function fe. It is determined as one charge / discharge power function fe used in the power determination means 29. These determinations are made when, for example, prior information is updated.

  According to the power supply control device 6 according to the present embodiment as described above, one output limiting function ft, one target charge state function fp, and one target charge state function fp based on the prior gradient θp (preliminary information) and the secondary battery temperature Tb. One charge / discharge power function fe is determined. Therefore, appropriate power control can be performed from the viewpoint of energy efficiency, running performance, and power source life.

  In the above description, the prior information is assumed to be the prior gradient θp. However, prior information is not limited to this. For example, even if the prior information includes the speed limit of the road on which the vehicle is about to travel in the near future (hereinafter referred to as “future driving road”), the degree of traffic congestion, and the possibility of a stop display by a signal Good. For example, if the speed limit on the future driving road is low, the degree of traffic congestion on the future driving road is high, or if the signal display on the future driving road is likely to be “red”, The possibility of slowing down is considered high. Therefore, in these cases, a travel mode emphasizing regeneration is assigned, such as the travel mode assigned when the prior gradient θp indicates a downhill. On the other hand, if the speed limit on the future driving road is high, or if the degree of traffic congestion on the future driving road is low, the possibility of acceleration in the future is considered high. Therefore, in these cases, a powering-oriented travel mode is assigned, such as the travel mode assigned when the pre-gradient θp indicates climbing.

  6 power supply control device, 21 operation detection means, 22 running state detection means, 23 power supply state detection means, 24 required output determination means, 25 control function determination means, 26 output limit determination means, 27 required output distribution means, 28 target charge state Determination means, 29 Charge / discharge power determination means, 30 Power output determination means, 31 Power output control means, 32 Prior information detection means.

Claims (4)

A power supply control device that is provided in a vehicle and controls output from a main power supply and an assist power supply,
Operation detecting means for detecting an operation on the vehicle;
Traveling state detecting means for detecting the traveling state of the vehicle;
Power supply state detection means for detecting a temperature related to the main power supply and a charge state of the assist power supply;
Request output determination means for determining a request output required for the main power supply and the assist power supply as a whole based on the operation and the running state;
A plurality of output limiting functions, a plurality of target charge state functions, and a plurality of charge / discharge power functions, each of which includes one output limit function, one target charge state function, and one Control function determining means for respectively determining the charge / discharge power function;
Output limit determination means for determining an output limit of the assist power source based on the required output, a charge state of the assist power source, and the one output limit function;
Request output distribution means for distributing the request output to the main power supply and the assist power supply based on the request output and the output limit of the assist power supply;
Target charging state determination means for determining a target charging state of the assist power source based on the running state and the one target charging state function;
Charge / discharge power determining means for determining charge / discharge power between the main power supply and the assist power supply based on the charge state, the target charge state, and the one charge / discharge power function;
Power output determining means for determining outputs of the main power supply and the assist power supply based on the charge / discharge power, the required output distributed to the main power supply, and the required output distributed to the assist power supply; ,
Power output control means for controlling the outputs of the main power and the assist power based on the outputs of the main power and the assist power determined by the power output determining means,
The control function determining means obtains power consumption, shortage power and power supply deterioration value, and applies a weighting factor to each of the power consumption, shortage power and power supply deterioration value, and obtains an evaluation value obtained by summing them. A power supply control device that calculates and determines the one output limit function, the one target charge state function, and the one charge / discharge power function so that the evaluation value falls within a predetermined range. The power supply control device according to claim 1,
The traveling state includes a vehicle speed,
Each of the plurality of target charge state functions is a function of the vehicle speed indicating the target charge state,
In each of the plurality of target charge state functions, the target charge state is low when the vehicle speed is high, and the target charge state is high when the vehicle speed is low. The power supply control device according to claim 1 or 2,
Each of the plurality of charge / discharge power functions is a power control device that is a function of a difference between the charge state of the assist power source and the target charge state of the assist power source, which indicates the charge / discharge power. A power supply control device that is provided in a vehicle and controls output from a main power supply and an assist power supply,
Operation detecting means for detecting an operation on the vehicle;
Traveling state detecting means for detecting the traveling state of the vehicle;
Power supply state detection means for detecting a temperature related to the main power supply and a charge state of the assist power supply;
Request output determination means for determining a request output required for the main power supply and the assist power supply as a whole based on the operation and the running state;
A plurality of output limiting functions, a plurality of target charge state functions, and a plurality of charge / discharge power functions, each of which includes one output limit function, one target charge state function, and one Control function determining means for respectively determining the charge / discharge power function;
Output limit determination means for determining an output limit of the assist power source based on the required output, a charge state of the assist power source, and the one output limit function;
Request output distribution means for distributing the request output to the main power supply and the assist power supply based on the request output and the output limit of the assist power supply;
Target charging state determination means for determining a target charging state of the assist power source based on the running state and the one target charging state function;
Charge / discharge power determining means for determining charge / discharge power between the main power supply and the assist power supply based on the charge state, the target charge state, and the one charge / discharge power function;
Power output determining means for determining outputs of the main power supply and the assist power supply based on the charge / discharge power, the required output distributed to the main power supply, and the required output distributed to the assist power supply; ,
Power supply output control means for controlling the outputs of the main power supply and the assist power supply based on the outputs of the main power supply and the assist power supply determined by the power supply output determination means, and advance information on the road on which the vehicle is about to travel A prior information detecting means for detecting
The control function determining means includes
It has a plurality of driving modes respectively associated with a combination of a plurality of output limiting functions, a plurality of target charge state functions, and a plurality of charge / discharge power functions, and based on the prior information and the temperature related to the main power source Selecting one driving mode from the plurality of driving modes, and outputting the output limiting function, the target charging state function, and the charge / discharge power function associated with the one driving mode to the one output A power supply control device that determines the limiting function, the one target charge state function, and the one charge / discharge power function, respectively.

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