JP2007244093A - Power supply control method for power supply devices for vehicles and power supply device for vehicles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further adjust output voltage when batteries are connected in parallel and thereby reduce troubles arising from a difference between an applied voltage requested and an output voltage actually outputted. <P>SOLUTION: A power supply device for vehicles includes: multiple batteries that can be electrically connected in series-parallel with a motor for driving a vehicle; multiple switch means for switching one of the batteries to be connected to the motor; and a controller for controlling the operation of the multiple switch means. The controller performs the following operation to control the operation of the multiple switch means when one or more of the batteries are connected in parallel with the motor: it selects a number (N; however, N≥1) of parallel connections so that the output voltage Vpn from one or more batteries connected in parallel becomes closest to a requested applied voltage Vmin by voltage change ΔV in each battery due to its internal resistance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power supply control method for a vehicle power supply device and a vehicle power supply device.

An electric vehicle incorporates a vehicle power supply device having a plurality of power storage means that can be electrically connected to a vehicle driving motor (see Patent Document 1). The vehicle power supply device disclosed in Patent Document 1 is configured to be able to switch a plurality of power storage means to a serial connection or a parallel connection, and by switching the series storage of the plurality of power storage means, The output voltage is changed. Specifically, when the required applied voltage is small, all of the plurality of power storage means are connected in parallel to reduce the output voltage, and when the required applied voltage is large, all of the plurality of power storage means Are connected in series to increase the output voltage.
Japanese Patent Laid-Open No. 5-236608

  However, the vehicle power supply device disclosed in Patent Document 1 merely switches the series-parallel of the plurality of power storage means, and when all of the plurality of power storage means are connected in parallel, the required applied voltage and A defect due to a difference from the output voltage actually output occurs. The “required applied voltage” is generally determined in consideration of minimizing various losses such as motor loss and inverter loss. Therefore, when the difference between the required applied voltage and the output voltage that is actually output increases, the above-described various losses increase.

  The object of the present invention is to enable further adjustment of the output voltage when the power storage means are connected in parallel, and to thereby reduce problems caused by the difference between the required applied voltage and the actually output voltage. Another object is to provide a power supply control method for a vehicle power supply device and a vehicle power supply device.

In order to achieve the above object, the invention described in claim 1
A plurality of power storage means that can be electrically connected in series and parallel to a motor for driving a vehicle, and the number of parallel connections (N, where N ≧ 1) to be connected in parallel to the motor can be selected from the plurality of power storage means. In a power supply control method for a vehicular power supply device,
When one or more of the plurality of power storage means are connected in parallel to the motor, the output voltage from the one or more power storage means when connected in parallel is caused by a voltage change caused by the internal resistance of each power storage means. The power supply control method for a vehicle power supply apparatus is characterized in that the number of parallel connections (N) is selected so as to be closest to the required applied voltage.

In order to achieve the above object, the invention according to claim 7 provides:
A plurality of power storage means that can be electrically connected in series and parallel to a vehicle driving motor;
A plurality of switch means for switching the power storage means connected to the motor from the plurality of power storage means;
A controller for controlling the operation of the plurality of switch means;
Have
When the controller connects one or more of the plurality of power storage means to the motor in parallel, the output voltage from the one or more power storage means when connected in parallel is the internal resistance of each power storage means. The number of parallel connections (N, where N ≧ 1) is selected so that the required applied voltage is closest to the voltage change caused by the control, and the operation of the plurality of switch means is controlled. Power supply device.

  According to the present invention, it is possible to further adjust the output voltage when the power storage means are connected in parallel by connecting the power storage means of the selected number of parallel connections to the motor in parallel and using the voltage change due to the internal resistance of each power storage means. It becomes possible. Through this, it is possible to reduce defects caused by the difference between the required applied voltage and the actually output voltage.

(First embodiment)
Hereinafter, a power supply control method for a vehicle power supply apparatus according to the present invention and a vehicle power supply apparatus according to the present invention that embodies the method will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a schematic configuration of a vehicle according to a first embodiment of the present invention, and FIG. 2 is a diagram illustrating a configuration of a circuit unit 2a in the vehicle power supply device 1 according to the first embodiment. 3 is a block diagram illustrating a configuration of a controller 2b in the vehicle power supply device 1 according to the first embodiment.

  As shown in FIG. 1, an electric vehicle as a vehicle includes an AC motor 3 (vehicle driving motor) that is rotationally driven by electric power supplied from a vehicle power supply device 1 (hereinafter referred to as “power supply device”). (Hereinafter referred to as “motor”), a speed reducer 4 connected to the output shaft of the motor 3, a differential device 5 connected to the speed reducer 4, and a motor 3 connected to the differential device 5. Wheel 6a, 6b which is rotated by being transmitted. The power supply device 1 includes a circuit unit 2a and a controller 2b that controls the operation of the circuit unit 2a. Moreover, the electric vehicle has a plurality of sensors 7 that detect predetermined information indicating the driving state of the vehicle. The sensor 7 is connected to the controller 2b. An output signal from the sensor 7 is input to the controller 2b. The sensor 7 includes an accelerator pedal sensor (APS) that is attached to an accelerator pedal and detects an accelerator opening, a wheel speed sensor, and the like (see FIG. 3).

  As shown in FIG. 2 and FIG. 3, the power supply device 1, if outlined, is a plurality of secondary batteries 11, 12, 13 (which are electrically connected in series and parallel to the motor 3 via the inverter 14. And a plurality of switches SW1 to SW5 and SW11 to SW13 (corresponding to the switch means) for switching the batteries 11, 12, and 13 connected to the motor 3 from the plurality of batteries 11, 12, and 13. And a controller 2b for controlling the operation of the plurality of switches SW1 to SW5 and SW11 to SW13. When the controller 2 b connects one or more of the batteries 11, 12, 13 to the motor 3 in parallel, the output voltage from the one or more batteries when connected in parallel is the output voltage of each battery 11. The number of parallel connections is selected so that the required applied voltage is closest to the voltage change caused by the internal resistances 11b, 12b, and 13b of each of the switches SW1 to SW13 and the switches SW1 to SW5 and SW11 to SW13 are operated. Is controlling. In addition, although the number of batteries is not limited as long as it is plural, in the present embodiment, the power supply device 1 including three batteries 11, 12, 13 will be described.

  The output voltage (corresponding to the input voltage to the inverter 14) from one or a plurality of batteries when connected in parallel to the motor 3 uses the symbol “Vpn”. The subscript “pn” of the output voltage Vpn indicates that n batteries are connected in parallel. For example, the output voltage from the three batteries when the three batteries are connected in parallel is expressed as “Vp3”. The sign “ΔV” is used for voltage change due to the internal resistances 11b, 12b, and 13b of the battery, and the sign “Vmin” is used for the required applied voltage. The symbol “N” is used for the number of parallel connections. However, N ≧ 1. Note that both n and N mean the number of parallel connections, but n is used in the control process, and when the number of parallel connections is finally determined, N = n and N is used. As described above, the present invention aims to enable further adjustment of the output voltage when the batteries are connected in parallel. When connecting the batteries to the motor 3 in parallel, one battery is selected as the number of connections. It is possible that In this case, the one battery is electrically connected to the motor 3 in series. However, in view of the above-described object of the present invention, even when the number of connections is 1, the number of parallel connections is N. Must be understood to be included. Details will be described below.

  The plurality of batteries 11, 12, and 13 are arranged to be connected in series and parallel to the inverter 14 in the circuit unit 2 a. The circuit unit 2a is also provided with a charging resistor 15 that suppresses inrush current.

  The battery 11 is configured by connecting a plurality of unit batteries 11a in series, and each of the batteries 12 and 13 is similarly configured by connecting a plurality of unit batteries 12a and 13a in series. In the battery 11, there is a difference between the sum of the voltages of the plurality of unit batteries 11 a when not energized, that is, the open voltage, and the output voltage when the motor 3 is actually driven. Similarly, in each of the batteries 12 and 13, there is a difference between the open voltage and the output voltage in the energized state. This is because a voltage change ΔV occurs due to the internal resistances 11b, 12b, and 13b of the batteries 11, 12, and 13 when the motor is driven.

  Here, the voltage change ΔV caused by the internal resistances 11b, 12b, and 13b of the batteries 11, 12, and 13 will be described.

  The voltage change ΔV due to the internal resistances 11b, 12b, and 13b of the batteries 11, 12, and 13 is calculated from the current I that flows through the battery when the motor is driven and the internal resistance value r, as shown in the following equation (1). be able to. At this time, the voltage change ΔV due to the internal resistance occurs in the direction opposite to the direction of the current I. That is, in the present embodiment, when the motor is powered, the output voltage of the battery is smaller than the open circuit voltage by the voltage change ΔV due to the internal resistance, and during motor regeneration, it is increased by the voltage change ΔV.

  In this equation, if the internal resistance value r is constant, the voltage change ΔV due to the internal resistance depends only on the current I to the battery when the motor is driven. From equation (1), the voltage change ΔV changes in proportion to the current I.

  The battery 11 and the battery 12 can be switched in series and parallel and connected in a single manner by controlling the switches SW11 to SW13 on and off. The switch SW11 is disposed between the positive electrode of the battery 11 and the positive electrode of the battery 12, and the switch SW12 is disposed between the negative electrode of the battery 11 and the negative electrode of the battery 12. A switch SW13 is disposed on a path connecting the positive electrode of the battery 11 and the switch SW11 to a path connecting the negative electrode of the battery 12 and the switch SW12.

  The circuit portion including the battery 11, the battery 12, and SW11 to SW13 in which the battery 11 and the battery 12 can be switched in series and parallel and surrounded by a broken line shown in FIG. 2 is hereinafter referred to as a “battery group 16”. When a path connected to another component is connected to the positive electrode side of the battery group 16, this path is connected to a path connecting the switch SW <b> 11 and the positive electrode of the battery 12. When a path connecting to another component is connected to the negative electrode side of the battery group 16, this path is connected to a path connecting the switch SW 12 and the negative electrode of the battery 11.

  The circuit unit 2a can further switch the battery group 16 and the battery 13 in series and parallel by controlling the switches SW1 to SW5 on and off, and only one of the battery group 16 and the battery 13 is supplied to the inverter 14. It is possible to connect.

  The switch SW1 is disposed on a path connecting the positive electrode of the battery group 16 and the negative electrode of the battery 13, and the charging resistor 15 is disposed between the positive electrode of the battery group 16 and the switch SW1.

  The switch SW <b> 2 is arranged on a path connecting from the path connecting the positive electrode of the battery group 16 and the charging resistor 15 to the negative electrode of the battery 13.

  Switch SW3 is from the path connecting charging resistor 15 and switch SW1 to the positive electrode of inverter 14 (hereinafter, the side connected to the positive electrode side of each battery is the positive electrode of inverter 14. The negative electrode is also the same). It is arranged on the route that leads to.

  The switch SW4 is arranged on a path connecting the positive electrode of the battery group 16 and the positive electrode of the inverter 14, and the switch SW5 is arranged on a path connecting the negative electrode of the battery 13 and the negative electrode of the inverter 14.

  FIG. 4 shows an example of a battery connection mode realized by on / off control of the switch. In the figure, ◯ indicates that the switch is turned on, and x indicates that the switch is turned off. Combinations are indicated using battery symbols “11”, “12”, “13”.

  As illustrated, the batteries 11 to 13 are connected in a single connection, a plurality of parallel connections, or a plurality of series connections to the inverter 14 by controlling the switches SW1 to SW5 and the switches SW11 to SW13 on and off. The on / off control of the illustrated switch is only a path used in the present embodiment, and is merely an example for forming a path that does not pass through the charging resistor 15. It goes without saying that it is possible to form a path of

  As shown in FIG. 3, the controller 2b includes a target driving force setting unit 21, a driving motor output setting unit 22, a minimum loss applied voltage calculation unit 23, an open-circuit voltage detection unit 24, and a series / parallel determination unit. 25, a parallel connection number determination unit 26a, and a switch control unit 27. The controller 2b stores in advance processing programs and control maps necessary for arithmetic processing, and sequentially stores signals from the sensor 7 and arithmetic processing results. First, an outline of each part will be described. Details of the control will be described separately along the flowchart.

  The target driving force setting unit 21 determines a target driving force for determining the motor output from the driving state of the vehicle. In the present embodiment, the target driving force is set by referring to the existing target driving force MAP based on the accelerator opening detected by the accelerator sensor (APS) and the vehicle speed calculated from each wheel speed sensor.

  The driving motor output setting unit 22 calculates a motor output from the target driving force and the vehicle speed. In the present embodiment, the motor output means a motor power calculated from a product of a motor torque calculated from the target driving force and a motor rotational speed calculated from the vehicle speed.

  The minimum loss applied voltage calculation unit 23 calculates an applied voltage (minimum loss applied voltage) at which the output loss during motor driving is minimized from the motor torque and the motor speed calculated by the driving motor output setting unit 22. Calculation is performed with reference to the loss MAP. This minimum loss applied voltage corresponds to the required applied voltage Vmin (hereinafter referred to as the minimum loss applied voltage Vmin). The minimum loss applied voltage Vmin here means an applied voltage that minimizes motor / inverter loss during motor driving. Motor / inverter loss is a general term for motor loss such as iron loss and copper loss, and inverter loss such as on loss and switching loss. Minimizing motor / inverter loss means minimizing a plurality of variable losses overall. The loss MAP is a general expression that represents the correlation among motor torque, motor rotation speed, and motor / inverter loss at each voltage.

  The open-circuit voltage detection unit 24 detects open-circuit voltages of the batteries 11, 12, and 13 and sets the average value as the average open-circuit voltage. The symbol “VaVe” is used for the average open-circuit voltage.

  The serial / parallel determination unit 25 determines whether or not the batteries 11, 12, and 13 can be connected in parallel based on the open voltage of the batteries 11, 12, and 13. When it is determined that the batteries 11, 12, and 13 can be connected in parallel, the series / parallel determination unit 25 determines to select the number of parallel connections and connects the batteries 11, 12, and 13 in parallel. Is determined to be impossible, it is determined that a plurality of the batteries 11, 12, and 13 are connected in series to the motor. In this embodiment, it is determined whether or not the batteries 11, 12, and 13 can be connected in parallel by comparing the average open circuit voltage VaVe of the batteries 11, 12, and 13 with the back electromotive force of the motor. . When the average open circuit voltage VaVe is higher than the back electromotive voltage of the motor, the control shifts to control of connecting one or more of the batteries 11, 12, and 13 described below to the motor in parallel. , 13 shifts to the control of connecting a plurality of them in series with the motor. In determining whether the batteries 11, 12, and 13 can be connected in parallel, the average open circuit voltage VaVe may be compared with a preset threshold value.

  The parallel connection number determination unit 26a determines whether the motor operation state is a power running state or a regenerative state, and performs control according to each.

  First, control during power running will be described.

  Here, in the power supply device 1 having the plurality of batteries 11, 12, 13, when the plurality of batteries 11, 12, 13 are connected in parallel, not all are simply connected in parallel, but the output voltage Vpn is further increased. A method for bringing the voltage close to the minimum loss applied voltage Vmin will be described.

  First, the average open circuit voltage VaVe and the minimum loss applied voltage Vmin are compared. When the average open circuit voltage VaVe is greater than the minimum loss applied voltage Vmin, the output voltage Vpn at each parallel connection number n (n = 1, 2, 3) is calculated. As described above, this output voltage Vpn is a voltage that takes into account a voltage change ΔV due to internal resistance during energization in a state where one or a plurality of batteries are connected in parallel. Then, the parallel connection number n having the smallest difference between the calculated output voltage Vpn and the minimum loss applied voltage Vmin at each calculated parallel connection number n is selected, and n is determined as the parallel connection number N. When the average open circuit voltage VaVe is equal to or lower than the minimum loss applied voltage Vmin, a state in which all the batteries 11, 12, 13 are connected in parallel is selected (n = 3), and n is determined as the number N of parallel connections. To do. By connecting all the batteries 11, 12, and 13 in parallel, the voltage change ΔV is minimized, and the output voltage Vpn is close to the minimum loss applied voltage Vmin. When the output voltage Vpn from one or more batteries becomes the minimum loss applied voltage Vmin, the efficiency of driving the motor during power running is the best. In the present embodiment, for ease of understanding, the internal resistances 11b, 12b, 13b of the plurality of batteries 11, 12, 13 are constant, and the battery is connected at each parallel connection number (N = 1, 2, 3). It is assumed that the voltage change ΔV in the internal resistors 11b, 12b, and 13b is constant regardless of which of 11, 12, and 13 is selected. As described above, the number N of parallel connections includes a single connection (N = 1).

  FIG. 5 shows the change in the number n of parallel connections based on the relationship between the average open circuit voltage VaVe and the minimum loss applied voltage Vmin (Vmin << VaVe, Vmin <VaVe, Vmin≈VaVe or Vmin> VaVe), and from the battery at that time Schematic diagram of the output voltage Vpn. In the motor power running state shown in FIG. 5, n = 1 is selected when Vmin << VaVe, n = 2 is selected when Vmin <VaVe, and n = 3 is selected when Vmin≈VaVe or Vmin> VaVe. . In the following drawings and calculation formulas, the average open circuit voltage VaVe is regarded as the open circuit voltage of each of the batteries 11, 12, and 13. The amount of change between the average open circuit voltage VaVe shown in FIG. 5 and the output voltage Vpn when n pieces are connected in parallel corresponds to the voltage change ΔV due to the internal resistances 11b, 12b, and 13b at the number n of parallel connections. When the number of parallel connections is 1, since the entire current flows through one battery to be connected, the voltage change ΔV is also large. On the other hand, when the number n of connections increases, the current I flowing through each battery to be connected is equally divided (1 / n), so that the voltage change ΔV decreases in proportion to the decrease in current.

  An example is described below. As preconditions, three batteries are provided, the average open-circuit voltage VaVe = 100 V, the internal resistance of each of the batteries 11, 12, 13 is 1Ω, the output (kW) to the inverter 14 is constant, and P = 2 kW.

  When all three batteries 11, 12, 13 are connected in parallel in the motor power running state (n = 3), the current I flowing to each battery 11, 12, 13 is 7.2A (the amount of current I flowing to the inverter 14 is 21. 6A), the voltage change ΔV in the internal resistances 11b, 12b, and 13b of the batteries 11, 12, and 13 is 7.2V, and the output voltage Vp3 at this time is 92.8V.

  Similarly, when two of the three batteries 11, 12, 13 are connected in parallel (n = 2), the energization amount I to the two connected batteries is 11.3A (the energization amount I flowing to the inverter 14 is 22.2). 5A), the voltage change ΔV in the internal resistance of the battery to be connected is 11.3 V, and the output voltage Vp2 at this time is 88.7 V.

  When only one of the three batteries 11, 12, and 13 is connected in parallel (n = 1), the energization amount I to the connected battery is 27.6A, and the voltage change ΔV in the internal resistance of the connected battery is 27. The output voltage Vp1 at this time is 72.4V. These numerical values can be calculated from the formulas in the flowchart described later.

  Thus, when three batteries 11, 12, and 13 are provided, by switching the number n of parallel connections, for example, 92.8V, 88.7V, and 72.4V can be output in three patterns. The number n of parallel connections closest to the minimum loss applied voltage Vmin may be selected to determine the number N of parallel connections. Next, control during regeneration will be described.

  First, as in powering, the average open circuit voltage VaVe and the minimum loss applied voltage Vmin are compared. When the average open circuit voltage VaVe is smaller than the minimum loss applied voltage Vmin, the output voltage Vpn at each parallel connection number n (n = 1, 2, 3) is calculated. Then, the parallel connection number n having the smallest difference between the calculated output voltage Vpn and the minimum loss applied voltage Vmin at each calculated parallel connection number n is selected, and n is determined as the parallel connection number N. When the average open circuit voltage VaVe is equal to or higher than the minimum loss applied voltage Vmin, a state in which all the batteries 11, 12, 13 are connected in parallel is selected (n = 3), and n is determined as the number N of parallel connections. To do. By connecting all the batteries 11, 12, and 13 in parallel, the voltage change ΔV is minimized, and the output voltage Vpn is close to the minimum loss applied voltage Vmin. When the output voltage Vpn from one or more batteries becomes the minimum loss applied voltage Vmin, the efficiency of driving the motor during regeneration is the best. In the present embodiment, for ease of understanding, the internal resistances 11b, 12b, 13b of the plurality of batteries 11, 12, 13 are constant, and the battery is connected at each parallel connection number (N = 1, 2, 3). It is assumed that the voltage change ΔV in the internal resistors 11b, 12b, and 13b is constant regardless of which of 11, 12, and 13 is selected. As described above, the number N of parallel connections includes a single connection (N = 1).

  FIG. 6 shows the change in the number n of parallel connections based on the relationship between the average open-circuit voltage VaVe and the minimum loss applied voltage Vmin (Vmin >> VaVe, Vmin> VaVe, Vmin≈VaVe or Vmin <VaVe), and from the battery at that time Schematic diagram of the output voltage Vpn. In the motor regeneration state shown in FIG. 6, n = 1 is selected when Vmin >> VaVe, n = 2 is selected when Vmin> VaVe, and n = 3 is selected when Vmin≈VaVe or Vmin <VaVe. . The amount of change between the average open circuit voltage VaVe shown in FIG. 6 and the output voltage Vpn when n pieces are connected in parallel corresponds to the voltage change ΔV due to the internal resistances 11b, 12b, and 13b at the number n of parallel connections. When the number of parallel connections is 1, since the entire current flows through one battery to be connected, the voltage change ΔV is also large. On the other hand, when the number n of connections increases, the current I flowing through each battery to be connected is equally divided (1 / n), so that the voltage change ΔV decreases in proportion to the decrease in current.

  An example is described below. As preconditions, three batteries are provided, the average open-circuit voltage VaVe = 100 V, the internal resistance of each of the batteries 11, 12, 13 is 1Ω, the output (kW) to the inverter 14 is constant, and P = 2 kW.

  When the three batteries 11, 12, 13 are all connected in parallel in the motor regeneration state (n = 3), the current I flowing to each battery 11, 12, 13 is 6.2A (the amount of current I flowing to the inverter 14 is 18.). 8A), the voltage change ΔV in the internal resistances 11b, 12b, and 13b of the batteries 11, 12, and 13 is 6.2V, and the output voltage Vp3 at this time is 106.2V.

  Similarly, when two of the three batteries 11, 12, 13 are connected in parallel (n = 2), the energization amount I to the two connected batteries is 9.2A (the energization amount I flowing to the inverter 14 is 18. 3A), the voltage change ΔV in the internal resistance of the battery to be connected is 9.2V, and the output voltage Vp2 at this time is 109.2V.

  When only one of the three batteries 11, 12, and 13 is connected in parallel (n = 1), the energization amount I to the connected battery is 17.1A, and the voltage change ΔV in the internal resistance of the connected battery is 17. The output voltage Vp1 at this time is 117.1V. These numerical values can be calculated from the formulas in the flowchart described later.

  Thus, when three batteries 11, 12, and 13 are provided, by switching the number n of parallel connections, for example, 106.2V, 109.2V, and 117.1V can be output in three patterns. The number n of parallel connections closest to the minimum loss applied voltage Vmin may be selected to determine the number N of parallel connections. The switch control unit 27 controls on / off of the plurality of switches SW1 to SW5 and SW11 to SW13 so that the number of connections N determined by the parallel connection number determination unit 26a described above is achieved. Realize the connection state.

  Next, processing executed in the controller 2b will be described according to a flowchart.

  FIG. 7 shows a basic flowchart of processing in the controller 2b.

  A target driving force of the motor 3 is set from various operating states (step S21 (hereinafter, “step S” is simply referred to as “S”)), a motor output is set (S22), and necessary for the motor output. The minimum loss applied voltage Vmin is calculated (S23). The open circuit voltages of the individual batteries 11, 12, and 13 are detected, and an average open circuit voltage VaVe that is an average value of them is calculated (S24). The average open circuit voltage VaVe is compared with the counter electromotive voltage of the motor 3 (S25). If the average open-circuit voltage VaVe is larger than the back electromotive voltage, the number N of parallel connections is controlled (S25; Yes, S26a), and if it is smaller, the series connection is determined (S25; No, S26b). Then, switch control is performed to realize the set connection state (S27).

  FIG. 8 is a flowchart showing details of the target driving force setting (S21). First, the accelerator opening and the vehicle speed are read from each sensor (S211, S212), the target driving force MAP created in advance from the correlation between the accelerator opening and the vehicle speed is referred to (S213), and the target driving force tF is set ( S214).

  FIG. 9 is a flowchart showing details of the motor output setting (S22). First, a motor torque tTm is calculated from the target driving force tF, tire radius, and gear ratio set in S214 (S221). The motor torque tTm is calculated from the following equation (2).

tTm = tF × (tire radius) / (gear ratio) (2)
It is.

  Next, the motor rotation speed Nm is calculated from the vehicle speed V, the tire circumference, and the gear ratio read in S212 (S222). The motor rotation speed Nm is calculated from the following equation (3). In this equation (3), VSP (vehicle speed pulse signal) is used as the vehicle speed V. In Equation (3) of the present embodiment, the motor rotation speed is calculated from the vehicle speed, but the rotation speed may be directly sensed by general motor control.

Nm = VSP / (tire circumference) × (gear ratio) (3)
It is.

  A motor output Pm is calculated from the calculated motor torque tTm and the motor rotational speed Nm (S223). The motor output Pm is calculated from the following equation (4).

Pm = tTm × Nm (4)
It is.

  FIG. 10 is a flowchart showing details of the minimum loss applied voltage calculation (S23). Based on the motor torque tTm and the motor rotation speed Nm calculated in steps S221 and 222, a voltage that minimizes the motor / inverter loss is calculated with reference to the existing loss MAP and is set as the minimum loss applied voltage Vmin (S231). ).

  FIG. 11 is a flowchart showing details of the open circuit voltage detection (S24). As the numbers for identifying the batteries 11, 12, and 13, numbers 1, 2, and 3 are set in advance for the batteries 11, 12, and 13, respectively. Moreover, 3 which is the total number of the batteries 11, 12, and 13 is preset in the variable Xmax.

  First, the initial value 1 is set to the variable x (S241), and the open circuit voltage V1 of the battery 11 in which the number x (x = 1) is set is detected (S242). It is determined whether or not the numbers x and Xmax are equal (S243). If they are not equal (S243; No), the variable x is incremented by 1 (S244), and the open circuit voltage V2 of the battery 12 in which the number x (x = 2) is set is detected (S242). Since it is determined in step S243 that the numbers x and Xmax are not equal, similarly, the variable x is incremented by 1 (S244), and the open circuit voltage V3 of the battery 13 in which the number x (x = 3) is set. Is detected (S242). When the detection of the open voltages V1, V2, and V3 of all the batteries 11, 12, and 13 is completed, the numbers x and Xmax become equal (S243; Yes), and the average open voltage VaVe is calculated from the following equation (5). (S245). The average open circuit voltage VaVe is calculated by dividing the total sum of the open circuit voltages Vx by the total number of batteries Xmax.

  FIG. 12 is a flowchart showing details of the determination of the number of parallel connections (26a). First, it is determined whether or not the motor torque tTm calculated in step S221 is equal to or greater than 0 (S261a). When the motor torque tTm is equal to or greater than 0 (S261a; Yes), a power running process is executed (S262a). When tTm is less than 0 (S261a; No), the regeneration process is executed (S263a). Details of the power running process (S262a) and the regeneration process (S263a) will be sequentially described below.

  FIG. 13 is a flowchart showing details of the power running process (S262a). First, the minimum loss applied voltage Vmin is compared with the average open circuit voltage VaVe, and only when the average open circuit voltage VaVe is larger than the minimum loss applied voltage Vmin, the following number n of parallel connections is selected (S2621a; Yes) When the average open circuit voltage VaVe is equal to or lower than the minimum loss applied voltage Vmin (S2621a; No), the maximum connection number Nmax of the plurality of batteries is set as the parallel connection number N (S2622a, S2628a). In the present embodiment, “3” is set as the maximum connection number Nmax.

  When the average open circuit voltage VaVe is larger than the minimum loss applied voltage Vmin (S2621a; Yes), the number of connections is set to the minimum n = 1 (S2623a), and the output voltage Vpn when the number of connections is n is calculated (S2624a). Then, it is determined whether or not n is the maximum number of connections Nmax. If the maximum number of connections Nmax is not reached (S2625a; No), the number of connections is increased by 1 (S2626a), and the output voltage Vpn at the number n of connections is set. Further, this is obtained (S2624a), and this is repeated until n reaches the maximum number of connections Nmax. When the connection number n reaches the maximum connection number Nmax, that is, when the output voltages Vpn (Vp1, Vp2, Vp3) for all the connection numbers have been calculated (S2625a; Yes), the output voltage Vpn and the applied voltage in each connection state The output voltage Vpn that minimizes the absolute value of the difference from Vmin is selected (S2627a), and the number n of connections at that time is set as the actual number N of parallel connections (S2628a). The output voltage Vpn is calculated from the following formulas (6) to (9).

  A method of calculating the output voltage Vpn when the number of connections is n will be described. A description will be given with reference to FIG. 15 showing an equivalent circuit of a plurality of batteries and a load. The output voltage V when the open circuit voltage is E, the internal resistance is r (R when there is one), and the load power [W] is Pbat can be calculated from the following equation (7). At this time, Pbat is output power from the battery to be connected, which is necessary when the motor output Pm calculated in step 223 is output. Pmin is a motor / inverter loss when the minimum loss applied voltage Vmin is applied, and can be obtained from the loss MAP.

        Pbat = Pm + Pmin (6)

  Further, when the number of connections is n and the n open circuit voltages E are all equal, the internal resistance r can be expressed by the following equation (8).

r = R / n (8)
It is.

  Substituting r in equation (8) into equation (7), the output voltage Vpn when the number of parallel connections is n can be calculated from equation (9) below.

  FIG. 14 is a flowchart showing details of the regeneration process (S263a). First, the minimum loss applied voltage Vmin and the average open circuit voltage VaVe are compared, and only when the average open circuit voltage VaVe is smaller than the minimum loss applied voltage Vmin, the following process of selecting the number n of parallel connections is performed (S2631a; Yes ) When the average open circuit voltage VaVe is equal to or higher than the minimum loss applied voltage Vmin (S2631a; No), the maximum connection number Nmax of a plurality of batteries is set as the parallel connection number N (S2632a, S2638a).

  When the average open circuit voltage VaVe is smaller than the minimum loss applied voltage Vmin (S2631a; Yes), the number of connections is set to the minimum n = 1 (S2633a), and the battery output voltage Vpn when the number of connections is n is calculated (S2634a). . Then, it is determined whether or not n is the maximum number of connections Nmax. If the maximum number of connections is not reached (S2635a; No), the number of connections is increased by 1 (S2636a), and the output voltage Vpn at the number of connections n is further increased. This is repeated (S2634a), and this is repeated until n reaches the maximum number of connections Nmax. When the number of connections n reaches the maximum number of connections Nmax, that is, when calculation of the output voltages Vpn (Vp1, Vp2, Vp3) for all the connections is completed (S2635a; Yes), the output voltage Vpn and applied voltage in each connection state The output voltage Vpn that minimizes the absolute value of the difference from Vmin is selected (S2637a), and the number n of connections at that time is set as the actual number N of parallel connections (S2638a).

  Referring to FIG. 7 again, when the process of determining the number of parallel connections (26a) or determining the series connection (S26b) is completed, the process proceeds to the process of switch control (S27). The controller 2b performs on / off control of the switches SW1 to SW5 and SW11 to SW13 so as to realize the determined parallel connection and the number N of parallel connections and the determined series connection (and the number of series connections). Thus, a series of processing ends.

  As described above, in the present embodiment, when the plurality of batteries 11, 12, 13 are connected in parallel, the output voltage Vpn from one or a plurality of batteries when connected in parallel depends on the internal resistance of each battery. The number N of parallel connections is selected so as to be closest to the required applied voltage, that is, the minimum loss applied voltage Vmin by the voltage change ΔV. Further, by connecting the selected number N of batteries in parallel to the motor 3 and using the voltage change ΔV due to the internal resistance of each battery, it is possible to further adjust the output voltage when the batteries are connected in parallel. Through this, it is possible to reduce problems caused by the difference between the minimum loss applied voltage Vmin and the output voltage Vpn that is actually output, for example, the problem of increased motor / inverter loss. Efficiency is realized.

  Further, when the motor 3 is in a power running state, the number N of parallel connections is reduced and the current to the internal resistance of each battery is increased as the average open circuit voltage VaVe of the battery is larger than the required applied voltage, that is, the minimum loss applied voltage Vmin. The voltage change ΔV due to the internal resistance is increased. As a result, the output voltage Vpn is adjusted so as to be close to the minimum loss applied voltage Vmin, and an increase in motor / inverter loss is suppressed, thereby realizing high efficiency of the power supply device.

  Furthermore, when the motor is in the regenerative state, the internal resistance of each battery is reduced by reducing the number N of parallel connections of the plurality of batteries as the average open circuit voltage VaVe of the batteries is smaller than the required applied voltage, that is, the minimum loss applied voltage Vmin. To increase the voltage change ΔV due to the internal resistance. As a result, the output voltage Vpn is adjusted so as to be close to the minimum loss applied voltage Vmin, and an increase in motor / inverter loss is suppressed, thereby realizing high efficiency of the power supply device.

  Furthermore, when the average open circuit voltage VaVe is smaller than the back electromotive force of the motor or when it is desired to further increase the output voltage, that is, when it is determined that it is impossible to connect a plurality of batteries in parallel, a plurality of batteries are connected in series. It is also possible to connect.

  In this embodiment, control is performed when a plurality of batteries are connected in parallel. However, even if a plurality of batteries are already connected in parallel, the control according to this embodiment is performed in parallel. Even if the number of connections N is changed, the same effect can be obtained.

  In the present embodiment, the target driving force is set with reference to a MAP created in advance, but calculation using a calculation formula is also possible.

  Furthermore, in the present embodiment, each of the batteries 11, 12, and 13 is composed of a plurality of unit batteries 11a, 12a, and 13. However, even when one unit battery is used, the effect of this embodiment is similarly achieved. Obtainable.

(Second Embodiment)
FIG. 16 is a block diagram illustrating a configuration of the controller 2b in the vehicle power supply device 1 according to the second embodiment. In addition, the same code | symbol is attached | subjected to the part which is common in 1st Embodiment, and the description is abbreviate | omitted in part.

  In the second embodiment, the values of all the internal resistances 11b, 12b, and 13b are uniform in that the values of the internal resistances 11b, 12b, and 13b of the batteries 11, 12, and 13 are estimated when the motor is actually driven. This is different from the first embodiment which is regarded as the above.

  As shown in FIG. 16, the controller 2b of the second embodiment is similar to the controller 2b of the first embodiment in that the target driving force setting unit 21, the driving motor output setting unit 22, and the minimum loss applied voltage The calculation part 23, the open circuit voltage detection part 24, the serial / parallel judgment part 25, and the switch control part 27 are provided. The controller 2b of the second embodiment includes an internal resistance estimation unit 26c and a parallel connection combination determination unit 26d instead of the parallel connection number determination unit 26a of the first embodiment.

  The internal resistance estimator 26c detects the voltages of the batteries 11, 12, and 13 when the motor is actually driven and the currents flowing through the batteries 11, 12, and 13 from the slope of the graph as shown in FIG. The internal resistance of each battery 11, 12, 13 is estimated.

  In the parallel connection combination determining unit 26d, first, as shown in FIG. 17, all parallel connection combinations c (c: combination) in the batteries 11, 12, and 13 are set in advance. However, the parallel connection combination c includes a case where any one of the plurality of batteries 11, 12, 13 is selected. Then, the output voltage Vc in each parallel connection combination c is calculated from the estimated internal resistance values of the batteries 11, 12, and 13. Then, any one parallel connection combination c that minimizes the difference between the output voltage Vc and the minimum loss applied voltage Vmin calculated in the same manner as in the first embodiment is selected, and the number N of parallel connections is determined. In the present embodiment, first, the number N of parallel connections is N ≧ 1 as in the first embodiment.

  Next, processing executed in the controller 2b to calculate the number N of parallel connections in the second embodiment will be described according to a flowchart.

  FIG. 18 shows a basic flowchart of processing in the controller 2b.

  As in the first embodiment, first, the target driving force of the motor is set from various operating states (S21), the motor output is set from the value (S22), and the minimum loss applied voltage Vmin necessary for the motor output is set. The calculation is performed (S23), and the open circuit voltages of the individual batteries 11, 12, 13 are detected to calculate the average open circuit voltage VaVe (S24). The average open circuit voltage VaVe is compared with the counter electromotive voltage of the motor 3 (S25). If the parallel connection state can be controlled (S25; Yes), the internal resistance of each of the batteries 11, 12, 13 at the actual motor output is estimated (S26c), and each parallel connection is determined from the value of the internal resistance. The output voltage Vc in the combination c is obtained and the parallel connection combination is determined (S26d).

  FIG. 19 is a flowchart showing details of the internal resistance estimation (S26c). First, x = 1 (x is an arbitrary number corresponding to the number of batteries as in the first embodiment), that is, any one battery is selected (S261c), and the number of samples is m = 1 (S262c). The voltage Vxm of the battery x (here, V = 1 from x = 1, m = 1) and the current Ixm (here, I11) flowing through the battery x are detected (S263c, S264c). Next, it is determined whether or not the maximum number of samples is m = Mmax. If the number is not the maximum (S265c), the number of samples is set to m = m + 1 (S266c), and step S263c and the subsequent steps are performed in a similar manner. S265c; Yes), each sample is plotted, and the internal resistance value Rx of the battery x (here, R1 if battery x = 1) is obtained from the slope of the graph as shown in FIG. 20 (S267c). By repeating the flow of S262c to S267c until x = Xmax (S268c; Yes) (S268c; No → S269c → S262c), the internal resistances R1, R2, R3,. Calculate Rx. The graph shown in FIG. 20 is an example when the number of batteries is three and two samples are plotted for each battery. In the graph, the vertical axis represents voltage Vxm, the horizontal axis represents current Ixm (having a charge region and a discharge region), the slope of the generated primary curve is defined as the internal resistance value Rx, and the intercept between the primary curve and the vertical axis. Is the open circuit voltage. Actually, each time the voltage Vxm and the current Ixm are measured according to the flowchart shown in FIG. 19, a sample of each battery is plotted on the coordinate axes similar to the graph of FIG. Then, the internal resistance value Rx is estimated from the created graph. The number m of samples is at least 2 or more, and the greater the number, the higher the accuracy. However, since the sample points plotted on the same graph need to be in a state where the storage state of each battery is close, the sample points are set within a predetermined time or within a predetermined energy balance range.

  FIG. 21 is a flowchart showing details of the parallel connection combination determination (S26d). First, based on the internal resistance value estimated in S26c, the expression shown in the first embodiment is the output voltage Vc (here, V1 from c = 1) at the time of combination of c = 1 shown in FIG. 17 (S261d). Calculation is performed by applying (6) to (9) (S262d). Next, the absolute value of the difference ΔVc (here, ΔV1 from c = 1) between the output voltage Vc and the minimum loss applied voltage Vmin calculated in the same manner as in the first embodiment is calculated (S263d). Similarly, c is incremented by 1 until c = Cmax (S265d), and the difference ΔVc between all parallel connection combinations c and the minimum loss applied voltage Vmin shown in FIG. 17 is calculated (S264d), and ΔVc is minimized. Cmin is selected, and the parallel connection combination Cmin is selected and set to the number N of parallel connections (S266d, S267d). For example, if Cmin = 5 is selected, N = 2 is set as the parallel connection number N from FIG. 17, and the battery 12 and the battery 13 are set as two batteries to be connected in parallel.

  In this embodiment, the internal resistance Rx of each battery when the motor outputs is estimated, and when selecting the parallel connection number N, the parallel connection of the batteries connected in parallel to the motor from the estimated value of the internal resistance Rx The output voltage Vc in the combination c is calculated. Then, by selecting the parallel connection combination c of the output voltage Vc closest to the minimum loss applied voltage Vmin from the parallel connection combination c, only the number of connections N shown in the first embodiment is adjusted, and the number of parallel connections Compared with the one that determines N, it is possible to further reduce the defects, and to achieve higher efficiency of the power supply apparatus more reliably.

1 is a diagram illustrating a schematic configuration of a vehicle according to a first embodiment of the present invention. It is a figure which shows the structure of the circuit part in the electric power supply apparatus for vehicles which concerns on 1st Embodiment. It is a block diagram which shows the structure of the controller in the vehicle electric power supply apparatus which concerns on 1st Embodiment. It is a graph which shows an example of the connection form of the battery implement | achieved by on / off control of a switch. It is the schematic which shows the state from which the output voltage of the battery to connect changes with the change of the parallel connection number at the time of the motor power running of 1st Embodiment. It is the schematic which shows the state from which the output voltage of the battery to connect changes with the change of the parallel connection number at the time of motor regeneration of 1st Embodiment. It is a basic flowchart which shows the process of the controller in 1st Embodiment. It is a flowchart which shows the detail of the target drive force setting in 1st Embodiment and 2nd Embodiment. It is a flowchart which shows the detail of the motor output setting in 1st Embodiment and 2nd Embodiment. It is a flowchart which shows the detail of the loss minimum applied voltage calculation in 1st Embodiment and 2nd Embodiment. It is a flowchart which shows the detail of the open circuit voltage detection in 1st Embodiment. It is a flowchart which shows the detail of the parallel connection number determination in 1st Embodiment. It is a flowchart which shows the detail of the process at the time of power running of FIG. It is a flowchart which shows the detail of the process at the time of regeneration of FIG. It is an equivalent circuit diagram which shows the calculation method of the output voltage of the battery to connect when the number of connections is n in 1st Embodiment. It is a block diagram which shows the structure of the controller in 2nd Embodiment. In 2nd Embodiment, it is a table | surface which shows the parallel connection combination of the battery in each connection number when there are three batteries. It is a basic flowchart which shows the process of the controller in 2nd Embodiment. It is a flowchart which shows the detail of internal resistance estimation in 2nd Embodiment. It is a map which calculates the internal resistance of each battery in 2nd Embodiment. It is a flowchart which shows the detail of the parallel connection combination determination in 2nd Embodiment.

Explanation of symbols

1 power supply device (vehicle power supply device),
2a circuit part,
2b controller,
3 AC motor (motor for driving the vehicle),
7 sensor,
11, 12, 13 battery (power storage means),
SW1 to SW5, SW11 to SW13 switches (switch means),
N number of parallel connection of batteries (where N ≧ 1),
Vpn The output voltage from n batteries connected in parallel,
ΔV Voltage change due to battery internal resistance,
Vmin Loss minimum applied voltage (required applied voltage),
VaVe The average open circuit voltage of each battery,
Rx battery internal resistance,
c Battery combination,
Vc The output voltage of the battery in each connection combination (c) of the battery.

Claims (7)

A plurality of power storage means that can be electrically connected in series and parallel to a motor for driving a vehicle, and the number of parallel connections (N, where N ≧ 1) to be connected in parallel to the motor can be selected from the plurality of power storage means. In a power supply control method for a vehicular power supply device,
When one or more of the plurality of power storage means are connected in parallel to the motor, the output voltage (Vpn) from the one or more power storage means when connected in parallel depends on the internal resistance of each power storage means. The power supply control method for a vehicle power supply apparatus, wherein the number of parallel connections (N) is selected so as to be close to a required applied voltage (Vmin) required by a voltage change (ΔV). A plurality of power storage means that can be electrically connected in series and parallel to a motor for driving a vehicle, and the number of parallel connections (N, where N ≧ 1) to be connected in parallel to the motor can be selected from the plurality of power storage means. In a power supply control method for a vehicular power supply device,
Calculating a required applied voltage (Vmin) required;
When one or more of the plurality of power storage means are connected in parallel to the motor, the output voltage (Vpn) from the one or more power storage means when connected in parallel depends on the internal resistance of each power storage means. Selecting the number of parallel connections (N) to be close to the required applied voltage (Vmin) by a voltage change (ΔV);
A power supply control method for a vehicle power supply device.   In the step of selecting the number of parallel connections, when the motor is in a power running state, the number of parallel connections (N) decreases as the average open circuit voltage (Vave) of the power storage means is larger than the required applied voltage (Vmin). The power supply control method of the vehicle power supply device according to claim 2, wherein:   In the step of selecting the number of parallel connections, when the motor is in a regenerative state, the number of parallel connections (N) decreases as the average open circuit voltage (Vave) of the power storage means is smaller than the required applied voltage (Vmin). The power supply control method of the vehicle power supply device according to claim 2, wherein: Prior to the step of selecting the number of parallel connections, further comprising the step of estimating an internal resistance (Rx) of each power storage means when the motor outputs,
When selecting the number of parallel connections (N), from the estimated value of the internal resistance (Rx), the output voltage (Vc) of the power storage means in each connection combination (c) of the power storage means connected in parallel to the motor. )
3. The combination (c) that is the output voltage (Vc) of the power storage unit closest to the required applied voltage (Vmin) is selected from the connection combinations (c). The electric power supply control method of the vehicle electric power supply apparatus of description. Prior to the step of selecting the number of parallel connections, further comprising the step of determining whether or not the power storage means can be connected in parallel based on an open voltage of the power storage means,
When it is determined that the power storage means can be connected in parallel, the step of selecting the number of parallel connections is performed, and when it is determined that the power storage means cannot be connected in parallel, The power supply control method for a vehicle power supply device according to claim 2, wherein a plurality of units are determined to be connected in series. A plurality of power storage means that can be electrically connected in series and parallel to a vehicle driving motor;
A plurality of switch means for switching the power storage means connected to the motor from the plurality of power storage means;
A controller for controlling the operation of the plurality of switch means;
Have
When the controller connects one or more of the plurality of power storage means to the motor in parallel, the output voltage (Vpn) from the one or more power storage means when connected in parallel, The number of parallel connections (N, where N ≧ 1) is selected so that the required applied voltage (Vmin) is close to the required applied voltage (Vmin) due to the voltage change (ΔV) due to the internal resistance of A power supply device for a vehicle, characterized by being controlled.

Images