WO2014033522A2

WO2014033522A2 - Power management device and power management method

Info

Publication number: WO2014033522A2
Application number: PCT/IB2013/001831
Authority: WO
Inventors: Hiroki Endo; Itaru Seta
Original assignee: Toyota Jidosha Kabushiki Kaisha; Fuji Jukogyo Kabushiki Kaisha
Priority date: 2012-08-29
Filing date: 2013-08-26
Publication date: 2014-03-06
Also published as: WO2014033522A3; JP2014050131A

Abstract

A power management device includes a control unit (50) configured to manage an exchange of electric power between a power device (MG, 30) and an electrical storage device (40) having a plurality of battery units (41, 42) connected in parallel with each other and configured to set an integral term of a feedback correction amount for a parameter for power management or a learning value for power management to 0 when any one of the plurality of battery units (41, 42) is isolated from the remaining battery unit.

Description

POWER MANAGEMENT DEVICE AND POWER MANAGEMENT METHOD

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The invention relates to a power management device and power management method that manage an exchange of electric power between a power device and an electrical storage device having a plurality of battery units connected in parallel with each other.

2. Description of Related Art

[0002] There is known an existing power management device of this type, which calculates a first locus length indicating the length of a locus drawn on a current axis by a first current value flowing through a first battery pack (battery unit) and a second locus length indicating the length of a locus drawn on the current axis by a second current value flowing through a second battery pack connected in parallel with the first battery pack, and detects activation of any one of current interrupting devices (CID) respectively provided at the first and second battery packs on the basis of the first and second locus lengths (for example, see Japanese Patent Application Publication No. 2012-138278 (JP 2012-138278 A)). When the power management device has detected activation of any one of the current interrupting devices due to occurrence of an abnormality in any one of the first and second battery packs, any one of a plurality of relays is controlled such that the battery pack in which the corresponding current interrupting device has been activated is isolated from the other battery pack.

[0003] In addition, there is known an existing power management device of this type, which includes a power limit value calculation unit that calculates an output power limit value indicating an electric power outputtable from an electrical storage unit including a plurality of electrical storage devices (battery units) connected in parallel with each other and a feedback control unit that, when at least one of detected values of a plurality of first current sensors that respectively detect input/output currents of the corresponding electrical storage devices and a second current sensor that detects an input/output current of the electrical storage unit exceeds a predetermined threshold, executes excess current feedback control for correcting the output power limit value on the basis of the excess amount (for example, see Japanese Patent Application Publication No. 2012-060787 (JP 2012-060787 A)).

[0004] In the electrical storage device having the plurality of battery units connected in parallel with each other as described above, at the time of isolating the battery unit having an abnormality from the other battery units, it is required to set parameters, and the like, for power management such that no failure occurs in power management while the abnormal battery unit is being isolated or after the abnormal battery unit has been isolated. However, JP 2012-138278 A and JP 2012-060787 A do not consider settings of parameters, and the like, for power management at the time when the abnormal battery unit is isolated.

SUMMARY OF THE INVENTION [0005] The invention provides a power management device and power management method that further properly allow power management while any one of a plurality of battery units connected in parallel with each other is being isolated or after the any one of the plurality of battery units has been isolated.

[0006] A first aspect of the invention provides a power management device including a control unit configured to manage an exchange of electric power between a power device and an electrical storage device having a plurality of battery units connected in parallel with each other, and configured to set an integral term of a feedback correction amount for a parameter for power management or a learning value for power management to 0 when any one of the plurality of battery units is isolated from the remaining battery unit.

[0007] The power management device is configured to manage an exchange of electric power between the power device and the electrical storage device having the plurality of battery units connected in parallel with each other and configured to set the integral term of the feedback correction amount for the parameter for power management or the learning value for power management to 0 when any one of the plurality of battery units is isolated from the remaining battery unit. In this way, while the any one of the battery units is being isolated or after the any one of the battery units has been isolated, the integral term of the feedback correction amount or the learning value before isolation is not inherited. Thus, it is possible to suppress power management using the parameter or the learning value that does not match an actual situation. Thus, with the power management device, it is possible to further properly carry out power management while any one of the plurality of battery units is being isolated or after the any one of the plurality of battery units has been isolated.

[0008] The control unit may be configured to set an allowable discharge power allowed to be discharged from the electrical storage device, correct the allowable discharge power using a discharge-side feedback correction amount, calculated on the basis of at least a charge/discharge current of the electrical storage device, as an allowable discharge power correction amount, and set the allowable discharge power correction amount to 0 and an integral term of the discharge-side feedback correction amount to 0 when any one of the plurality of battery units is isolated from the remaining battery unit. Thus, failure of power management while any one of the battery units is being isolated is suppressed, and limitation of the allowable discharge power more than necessary after the any one of the battery units has been isolated due to the influence of the integral term of the feedback correction amount accumulated before the battery unit is isolated is suppressed. Thus, it is possible to supply a sufficient electric power to a power supply target of the electrical storage device. The charge/discharge current of the electrical storage device may include any one of or all of charge/discharge currents of the individual battery units.

[0009] The power device may include an electric motor configured to be used as a power source for propelling an electromotive vehicle and an inverter configured to drive the electric motor, and the control unit may be configured to set a torque command for the electric motor to 0 when any one of the plurality of battery units is isolated from the remaining battery unit. In this way, when the torque command for the electric motor is set to 0 at the time when any one of the plurality of battery units is isolated from the remaining battery unit, it is possible to isolate the any one of the battery units from the remaining battery unit without shutting down the inverter. In this case, current flowing through the electric motor does not always become 0 even when the torque command for the electric motor is set to 0; however, by setting the integral term of the feedback correction amount at the time when the any one of the battery units is isolated to 0, it is possible to appropriately suppress failure of power management due to accumulation of the integral term even if current flows through the electric motor.

[0010] The control unit may be configured to set an allowable charge power with which the electrical storage device is allowed to be charged, correct the allowable charge power using a charge-side feedback correction amount, calculated on the basis of at least a charge/discharge current of the electrical storage device, as an allowable charge power correction amount, and set the allowable charge power correction amount to 0 and set an integral term of the charge-side feedback correction amount to 0 when any one of the plurality of battery units is isolated form the remaining battery unit. Thus, failure of power management while any one of the battery units is being isolated is suppressed, and limitation of the allowable charge power more than necessary after the any one of the battery units has been isolated due to the influence of the integral term of the feedback correction amount accumulated before the battery unit is isolated is suppressed. Thus, it is possible to further properly charge the electrical storage device, that is, the remaining battery unit. In this case as well, the charge/discharge current of the electrical storage device may include any one of or all of charge/discharge currents of the individual battery units.

[0011] A second aspect of the invention provides a power management method of managing an exchange of electric power between a power device and an electrical storage device having a plurality of battery units connected in parallel with each other. The power management method includes setting an integral term of a feedback correction amount for a parameter for power management or a learning value for power management to 0 when any one of the plurality of battery units is isolated from the remaining battery unit.

[0012] With this method, it is possible to further properly carry out power management while any one of the plurality of battery units is being isolated or after the any one of the plurality of battery units has been isolated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:

FIG. 1 is a schematic configuration view that shows an electric vehicle that is an example of a vehicle including an electronic control unit as a power management device according to the invention; and

FIG. 2 is a flowchart that shows an example of an input/output limit correction routine.

DETAILED DESCRIPTION OF EMBODIMENTS [0014] An embodiment of the invention will be described with reference to the accompanying drawings.

[0015] FIG. 1 is a schematic configuration view that shows an electric vehicle 10 that is an example of a vehicle including an electronic control unit that serves as a power management device according to the invention. The electric vehicle 20 shown in the drawing includes a motor MG, an inverter 30, an electrical storage device 40 and the electronic control unit (hereinafter, referred to as "ECU") 50. The motor MG is able to input or output power to a drive shaft 22 coupled to drive wheels DW. The inverter 30 is used to drive the motor MG. The electrical storage device 40 is able to exchange electric power with the motor MG via the inverter 30. The ECU 50 controls the entire vehicle.

[0016] As shown in FIG. 1 , the drive shaft 22 is coupled to the right and left drive wheels DW via a differential gear 24, and the like. The motor MG is a known synchronous generator motor that includes a rotor in which a permanent magnet is embedded and a stator around which three-phase coils are wound. The inverter 30, for example, includes six transistors (not shown) that serve as switching elements and six diodes (not shown) respectively connected in antiparallel with these transistors. The electrical storage device 40 includes a first battery unit 41 and a second battery unit 42 that are connected in parallel with each other. In the present embodiment, the first and second battery units 41, 42 each are, for example, a battery pack formed by connecting a plurality of single cells in series with each other. Each of the plurality of single cells is a lithium ion secondary battery or a nickel metal hydride battery. However, the first and second battery units 41, 42 each may be formed of a capacitor, or the like, instead of a secondary battery.

[0017] As shown in FIG. 1 , the electrical storage device 40, that is, the first and second battery units 41, 42, are electrically connected to the inverter 30 via a positive electrode line PL, a negative electrode line NL and a plurality of relays 43, 44, 45, 46. The positive electrode line PL is connected to the positive electrode of the inverter 30. The negative electrode line NL is connected to the negative electrode of the inverter 30. One end of the first relay 43 is connected to the positive electrode terminal of the first battery unit 41, and the other end of the first relay 43 is connected to the positive electrode line PL. One end of the second relay 44 is connected to the positive electrode terminal of the second battery unit 42, and the other end of the second relay 44 is connected to the positive electrode line PL. One end of the relay 45 is connected to the connection node between the negative electrode terminals of the first and second battery units 41, 42, and the other end of the relay 45 is connected to the negative electrode line NL. One end of the relay 46 is connected to the connection node between the negative electrode terminals of the first and second battery units 1 , 42, and the other end of the relay 46 is connected to the negative electrode line NL via a precharge resistor R. Thus, when the first and second relays 43, 44 and the relay 45 or the relay 46 are turned on, the first and second battery units 41 , 42 are connected in parallel with each other, and are also connected in parallel with the inverter 30. In addition, when any one of the first and second relays 43, 44 is turned off, one of the first and second battery units 41 , 42, corresponding to the turned-off one of the first and second relays 43, 44, is isolated from the other (and the inverter 30 and the motor MG).

[0018] In addition to the inverter 30 and the motor MG, as shown in FIG. 1 , a DC/DC converter 31 and an electrical device, such as a compressor that constitutes a vehicle cabin air conditioner 35, are connected to the electrical storage device 40. A low- voltage system including an auxiliary battery (low- voltage battery) and connected to a plurality of auxiliaries (all are not shown) is connected to the DC/DC converter 31. The DC/DC converter 31 includes switching elements, a transformer, and the like, (all are not shown), and is able to step down electric power from the electrical storage device 40 by executing on/off control over the switching elements and then supply the stepped-down electric power to the low-voltage system, that is, the auxiliary battery and the plurality of auxiliaries. A step-up converter may be interposed between the inverter 30 and the electrical storage device 40. The step-up converter steps up voltage from the electrical storage device 40 and then supplies the stepped-up voltage to the inverter 30, and steps down voltage from the inverter 30 and then supplies the stepped-down voltage to the electrical storage device 40.

[0019] The ECU 50 is configured as a microcomputer that mainly includes a CPU, and, in addition to the CPU, includes a ROM that stores various control programs, a RAM that temporarily stores data, input/output ports, and the like (all are not shown). An ignition signal from an ignition switch (start switch) 51 , a shift position SP from a shift position sensor 53 that detects a shift position corresponding to an operating position of a shift lever 52, an accelerator operation amount Acc from an accelerator pedal position sensor 55 that detects the depression amount of an accelerator pedal 54, a vehicle speed V from a vehicle speed sensor 58, and the like, are input to the ECU 50 via the input port.

[0020] In addition, the ECU 50 communicates with a brake electronic control unit (hereinafter, referred to as "brake ECU") 60, and exchanges various signals and data with the brake ECU 60. The brake ECU 60 is configured as a microcomputer that mainly includes a CPU (not shown), and controls a hydraulic brake device (not shown) that is able to apply friction braking force to the drive wheels DW and the other wheels (not shown). A brake pedal stroke BS is input to the brake ECU 60 via the input port from a brake pedal stroke sensor 57 that detects the depression amount of a brake pedal 56 as shown in the drawing. When the brake pedal 56 is depressed by a driver, the brake ECU 60 calculates a pedal depression force applied to the brake pedal 56 by the driver on the basis of the brake pedal stroke BS from the brake pedal stroke sensor 57, and sets a required braking force that is required by the driver on the basis of the calculated pedal depression force. Then, the brake ECU 60 sets a required regenerative braking torque for the motor MG using the set required braking force, the vehicle speed V and a prepared regenerative distribution ratio setting map, transmits the set required regenerative braking torque to the ECU 50, and controls the hydraulic brake device such that friction braking forces corresponding to shares are output.

[0021] Furthermore, a rotor rotation position from a rotation position detection sensor 70 that detects a rotation position of a rotor of the motor MG is input to the ECU 50 via the input port, and the ECU 50 calculates the electric angle, rotation angular velocity, rotation speed Nm, and the like, of the rotor of the motor MG on the basis of the rotor rotation position from the rotation position detection sensor 70. In addition, a charge/discharge current Ibl of the first battery unit 41 , a charge/discharge current Ib2 of the second battery unit 42 and a charge/discharge current Ibt of the electrical storage device 40 are input to the ECU 50. The charge/discharge current Ibl is detected by a first current sensor 71 connected to the positive electrode terminal of the first battery unit 41. The charge/discharge current Ib2 is detected by a second current sensor 72 connected to the positive electrode terminal of the second battery unit 42. The charge/discharge current Ibt is detected by a third current sensor 73 connected to the connection node between the positive electrode terminals of the first and second battery units 41, 42. Furthermore, a terminal voltage Vbl of the first battery unit 41 , a terminal voltage Vb2 of the second battery unit 42 and a terminal voltage Vbt of the electrical storage device 40 are input to the ECU 50. The terminal voltage Vbl is detected by a first voltage sensor 74 arranged between the terminals of the first battery unit 41. The terminal voltage Vb2 is detected by a second voltage sensor 75 arranged between the terminals of the second battery unit 42. The terminal voltage Vbt is detected by a third voltage sensor 76 arranged between the positive electrode line PL and the negative electrode line NL.

[0022] Switching control signals are output from the ECU 50 to the transistors of the inverter 30 and DC/DC converter 31 via the output port. The ECU 50 calculates a state of charge SOC indicating the percentage of charge of the electrical storage device 40 on the basis of accumulated values of the charge/discharge currents Ibl , Ib2, and calculates an output limit Wout as an allowable discharge power (positive value) that is an electric power allowed to be discharged from the electrical storage device 40 and an input limit Win as an allowable charge power (negative value) that is an electric power with which the electrical storage device 40 is allowed to be charged, on the basis of the state of charge SOC and a temperature Tb of the electrical storage device 40, which is detected by a temperature sensor (not shown). Furthermore, the ECU 50 corrects the output limit Wout so as to reduce (so as to reduce in absolute value) and corrects the input limit Win so as to increase (so as to reduce in absolute value) on the basis of the charge/discharge currents Ibl , Ib2, Ibt and the terminal voltages Vbl , Vb2, Vbt.

[0023] At the time of a travel of the thus configured electric vehicle 20, the ECU 50 sets a required torque Tr* (including a braking torque when the accelerator is released) that should be output to the drive shaft 22 and that corresponds to the accelerator operation amount Acc and the vehicle speed V using a required torque setting map (not shown). In addition, at the time of vehicle braking in which the brake pedal 56 is depressed by the driver, the ECU 50 sets a required regenerative braking torque from the brake ECU 60 as the required torque Tr*. The ECU 50 sets a torque command Tm* for the motor MG such that a torque based on the required torque Tr* is output to the drive shaft 22 within the range of the output limit Wout and input limit Win of the electrical storage device 40, and executes switching control over the inverter 30 in accordance with the set torque command Tm* and the rotation speed Nm.

[0024] Next, the procedure of correcting the output limit Wout and the input limit Win by the ECU 50 will be described. FIG. 2 is a flowchart that shows an example of an input/output limit correction routine that is executed by the ECU 50 at predetermined intervals after the ignition switch 51 is turned on.

[0025] At the time of a start of the input/output limit correction routine shown in

FIG. 2, the CPU (not shown) of the ECU 50 executes the process of inputting required data, such as the output limit Wout, the input limit Win, the charge/discharge currents Ibl , Ib2, Ibt from the first to third current sensors 71 to 73, the terminal voltages Vbl, Vb2, Vbt from the first to third voltage sensors 74 to 76 and a battery isolation flag Fbc (step SI 00). The output limit Wout and the input limit Win that are input in step SI 00 are separately set by the ECU 50 as described above, and are stored in the RAM (not shown).

[0026] The battery isolation flag Fbc is separately set by the ECU 50 and is stored in the RAM (not shown). In the present embodiment, the ECU 50 sets the battery isolation flag Fbc to 0 when both the first and second battery units 41 , 42 are normal, and sets the battery isolation flag Fbc to 1 when an abnormality has been detected in any one of the first and second battery units 41 , 42 (hereinafter, referred to as "abnormal battery unit") by an abnormality detection device, or the like (not shown). The ECU 50 sets the battery isolation flag Fbc to 0 at the timing at which the abnormal battery unit has been isolated from the other battery unit (hereinafter, referred to as "normal battery unit"). In the electric vehicle 20 according to the present embodiment, at the time when the abnormal battery unit is isolated from the normal battery unit, the torque command Tm* applied to the motor MG is set to 0 without shutting down the inverter 30 during a period from a start of isolation to an end of isolation.

[0027] After the process of inputting data in step SI 00, the ECU 50 calculates an output limit power feedback correction amount (discharge-side feedback correction amount) AWop for each of the first and second battery units 41 , 42 on the basis of the charge/discharge currents Ibl , Ib2 and terminal voltages Vbl, Vb2 of the first and second battery units 41 , 42, input in step S 100 (step S 110). In step S 110, the ECU 50 calculates a charge/discharge power Pbl of the first battery unit 41 by multiplying the charge/discharge current Ibl by the terminal voltage Vbl and calculates a charge/discharge power Pb2 of the second battery unit 42 by multiplying the charge/discharge current Ib2 by the terminal voltage Vb2, and then determines whether the calculated charge/discharge powers Pbl , Pb2 exceed an upper limit-side power threshold Pul that is a predetermined relatively large positive value. Then, the ECU 50 sets the output limit power feedback correction amount AWop of one of the charge/discharge powers Pbl, Pb2, lower than the upper limit-side power threshold Pul, to 0.

[0028] The ECU 50 calculates the output limit power feedback correction amount AWop for one of the charge/discharge powers Pbl , Pb2, which exceeds the upper limit-side power threshold Pul, in accordance with the following mathematical expression (1). According to the mathematical expression (1), the output limit power feedback correction amount AWop is calculated on the basis of an excess amount (Pbl - Pul) of the charge/discharge power Pbl with respect to the upper limit power threshold Pul and an excess amount (Pb2 - Pul) of the charge/discharge power Pb2 with respect to the upper limit power threshold Pul. The mathematical expression (1) is a relational expression in feedback control (PID control) for bringing the charge/discharge powers Pbl, Pb2 to at or below the upper limit-side power threshold Pul. In the mathematical expression (1), "kopp" is a proportional-term gain, "kopi" is an integral-term gain, and "kopd" is a derivative-term gain. In the mathematical expression (1), "Pb(j)" indicates any one of the charge/discharge powers Pbl , Pb2. In the present embodiment, when the output limit power feedback correction amount AWop calculated in accordance with the mathematical expression (1) does not fall within the range between a predetermined upper limit guard value and a predetermined lower limit guard value, the upper limit guard value or the lower limit guard value is reset as the output limit power feedback correction amount AWop. AWop = kopp-(PbO) - Pul) + kopi-i(Pb(j) - Pul)dt + kopd-d(PbG) - Pul)/dt (1)

[0029] Subsequently, the ECU 50 calculates an output limit current feedback correction amount (discharge-side feedback correction amount) AWoi on the basis of the charge/discharge current Ibt of the electrical storage device 40, input in step SI 00 (step SI 20). In step S I 20, the ECU 50 determines whether the charge/discharge current Ibt of the electrical storage device 40 exceeds an upper limit-side current threshold lul that is a predetermined relatively large positive value. When the charge/discharge current Ibt is smaller than or equal to the upper limit-side current threshold lul, the ECU 50 sets the output limit current feedback correction amount AWoi to 0.

[0030] When the charge/discharge current Ibt exceeds the upper limit-side current threshold lul, the ECU 50 calculates the output limit current feedback correction amount AWoi in accordance with the following mathematical expression (2). According to the mathematical expression (2), the output limit current feedback correction amount AWoi is calculated on the basis of an excess amount (Ibt - lul) of the charge/discharge current Ibt with respect to the upper limit-side current threshold lul. The mathematical expression (2) is a relational expression in feedback control (PID control) for bringing the charge/discharge current Ibt to at or below the upper limit-side current threshold lul. In the mathematical expression (2), "koip" is a proportional -term gain, "koii" is an integral-term gain, and "koid" is a derivative-term gain. In the present embodiment, when the output limit current feedback correction amount AWoi calculated in accordance with the mathematical expression (2) does not fall within the range between a predetermined upper limit guard value and a lower limit guard value, the upper limit guard value or the lower limit guard value is reset as the output limit current feedback correction amount AWoi.

AWoi = koip-(Ibt - lul) + koii /(Ibt - Iul)dt + koid-d(Ibt - Iul)/dt (2)

[0031] Furthermore, the ECU 50 calculates an output limit voltage feedback correction amount (discharge-side feedback correction amount) AWov on the basis of the terminal voltage Vbt of the electrical storage device 40, input in step SI 00 (step S I 30). In step SI 30, the ECU 50 determines whether the terminal voltage Vbt of the electrical storage device 40 is lower than a lower limit-side voltage value Vll that is a predetermined relatively large positive value. When the terminal voltage Vbt is higher than or equal to the lower limit-side voltage value Vll, the ECU 50 sets the output limit voltage feedback correction amount AWov to 0.

[0032] When the terminal voltage Vbt is lower than the lower limit-side voltage value Vll, the ECU 50 calculates an output limit voltage feedback correction amount AWov in accordance with the following mathematical expression (3). According to the mathematical expression (3), the output limit voltage feedback correction amount AWov is calculated on the basis of an excess amount (Vbt - Vll) of the terminal voltage Vbt with respect to the lower limit-side voltage value Vll. The mathematical expression (3) is a relational expression in feedback control (PID control) for bringing the terminal voltage Vbt to at or above the lower limit-side voltage value Vll. In the mathematical expression (3), "kovp" is a proportional-term gain ,"kovi is an integral-term gain, and "kovd" is a derivative-term gain. In the present embodiment, when the output limit voltage feedback correction amount AWov calculated in accordance with the mathematical expression (3) does not fall within the range between a predetermined upper limit guard value and a predetermined lower limit guard value, the upper limit guard value or the lower limit guard value is reset as the output limit voltage feedback correction amount AWov.

AWov = kovp-(Vbt - Vll) + kovi-j(Vbt - Vll)dt + kovd-d(Vbt - Vll)/dt (3)

[0033] In this way, when a plurality of correction amounts, i.e., the output limit power feedback correction amount A Wop, the output limit current feedback correction amount AWoi and the output limit voltage feedback correction amount AWov, are calculated, the ECU 50 sets the sign of each of the feedback correction amounts A Wop, AWoi, AWov to positive, and sets a maximum value among the plurality of correction amounts, i.e., output limit power feedback correction amount A Wop, output limit current feedback correction amount AWoi and output limit voltage feedback correction amount AWov, as the output limit correction amount AWout (step S I 40).

[0034] Subsequently, the ECU 50 calculates an input limit power feedback correction amount (charge-side feedback correction amount) AWip for each of the first and second battery units 41, 42 on the basis of the charge/discharge currents Ibl, Ib2 and terminal voltages Vbl , Vb2 of the first and second battery units 41, 42, input in step SI 00 (step SI 50). In step SI 50, the ECU 50 calculates a charge/discharge power Pbl of the first battery unit 41 by multiplying the charge/discharge current Ibl by the terminal voltage Vbl , and calculates a charge/discharge power Pb2 of the second battery unit 42 by multiplying the charge/discharge current Ib2 by the terminal voltage Vb2. Then, the ECU 50 determines whether the calculated charge/discharge powers Pbl , Pb2 are lower than a lower limit-side power threshold Pll that is a negative value having a predetermined relatively large absolute value. Then, the ECU 50 sets the input limit power feedback correction amount AWip of one of the charge/discharge powers Pbl , Pb2, higher than or equal to the lower limit-side power threshold Pll, to 0.

[0035] The ECU 50 calculates the input limit power feedback correction amount AWip for one of the charge/discharge powers Pbl , Pb2, which is lower than the lower limit-side power threshold Pll, in accordance with the following mathematical expression (4). According to the following mathematical expression (4), the input limit power feedback correction amount AWip is calculated on the basis of an excess amount (Pbl - Pll) of the charge/discharge power Pbl with respect to the lower limit-side power threshold Pll and an excess amount (Pb2 - Pll) of the charge/discharge power Pb2 with respect to the lower limit-side power threshold Pll. The mathematical expression (4) is a relational expression in feedback control (PID control) for bringing the charge/discharge powers Pbl , Pb2 to at or above the lower limit-side power threshold Pll. In the mathematical expression (4), "kipp" is a proportional-term gain, "kipi" is an integral-term gain, and "kipd" is a derivative-term gain. In the mathematical expression (4), "Pb(j)" indicates any one of the charge/discharge powers Pbl , Pb2. In the present embodiment, when the input limit power feedback correction amount AWip calculated in accordance with the mathematical expression (4) does not fall within the range between a predetermined upper limit guard value and a predetermined lower limit guard value, the upper limit guard value or the lower limit guard value is reset as the input limit power feedback correction amount AWip. AWip = kipp-(PbO) - PH) + kipi-/(PbQ) - PU)dt + kipd-d(PbG) - PU)/dt (4)

[0036] Subsequently, the ECU 50 calculates an input limit current feedback correction amount (charge-side feedback correction amount) AWii on the basis of the charge/discharge current Ibt of the electrical storage device 40, input in step SI 00 (step SI 60). In step SI 60, the ECU 50 determines whether the charge/discharge current Ibt of the electrical storage device 40 is smaller than a lower limit-side current threshold 111 that is a negative value having a predetermined relatively large absolute value. When the charge/discharge current Ibt is larger than or equal to the lower limit-side current threshold 111, the ECU 50 sets the input limit current feedback correction amount AWii to 0.

[0037] When the charge/discharge current Ibt is smaller than the lower limit-side current threshold 111, the ECU 50 calculates the input limit current feedback correction amount AWii in accordance with the following mathematical expression (5). According to the mathematical expression (5), the input limit current feedback correction amount AWii is calculated on the basis of an excess amount (Ibt - 111) of the charge/discharge current Ibt with respect to the lower limit-side current threshold 111. The mathematical expression (5) is a relational expression in feedback control (PID control) for bringing the charge/discharge current Ibt to at or above the lower limit-side current threshold 111. In the mathematical expression (5), "kiip" is a proportional-term gain, "kiii" is an integral-term gain ,and "kiid" is a derivative-term gain. In the present embodiment, when the input limit current feedback correction amount AWii calculated in accordance with the mathematical expression (5) does not fall within the range between a predetermined upper limit guard value and a predetermined lower limit guard value, the upper limit guard value or the lower limit guard value is reset as the input limit current feedback correction amount AWii.

AWii = kiip-(Ibt - 111) + kiii-J(Ibt - IU)dt + kiid-d(Ibt - Ill)/dt (5)

[0038] Furthermore, the ECU 50 calculates the input limit voltage feedback correction amount (charge-side feedback correction amount) AWiv on the basis of the terminal voltage Vbt of the electrical storage device 40, input in step SI 00 (step SI 70). In step SI 70, the ECU 50 determines whether the terminal voltage Vbt of the electrical storage device 40 is higher than an upper limit-side voltage threshold Vul that is a predetermined positive value. When the terminal voltage Vbt is lower than or equal to the upper limit-side voltage threshold Vul, the ECU 50 sets the input limit voltage feedback correction amount AWiv to 0.

[0039] When the terminal voltage Vbt is higher than the upper limit-side voltage threshold Vul, the ECU 50 calculates the input limit voltage feedback correction amount AWiv in accordance with the following mathematical expression (6). According to the mathematical expression (6), the input limit voltage feedback correction amount AWiv is calculated on the basis of an excess amount (Vbt - Vul) of the terminal voltage Vbt with respect to the upper limit-side voltage threshold Vul. The mathematical expression (6) is a relational expression in feedback control (PID control) for bringing the terminal voltage Vbt to at or below the upper limit-side voltage threshold Vul. In the mathematical expression (6), "kivp" is a proportional-term gain, "kivi" is an integral-term gain, and "kivd" is a derivative-term gain. In the present embodiment, when the input limit voltage feedback correction amount AWiv calculated in accordance with the mathematical expression (6) does not fall within the range between a predetermined upper limit guard value and a predetermined lower limit guard value, the upper limit guard value or the lower limit guard value is reset as the input limit voltage feedback correction amount AWiv. AWiv = kivp-(Vbt - Vul) + kivi-i(Vbt - Vul)dt + kivd-d(Vbt - VulVdt (6)

[0040] In this way, when the input limit power feedback correction amount AWip, the input limit current feedback correction amount AWii and the input limit voltage feedback correction amount AWiv are calculated, the ECU 50 sets the sign of each of the feedback correction amounts AWip, AWii, AWiv to negative, and sets a minimum value among the plurality of correction amounts, i.e., input limit power feedback correction amount AWip, input limit current feedback correction amount AWii and input limit voltage feedback correction amount AWiv, as the input limit correction amount A Win (step SI 80).

[0041] After the process of step S 180, the ECU 50 determines whether the battery isolation flag Fbc input in step SI 00 is 1, that is, whether the first battery unit 41 or the second battery unit 42 is being isolated (step SI 90). When the battery isolation flag Fbc is 0 and the first battery unit 41 or the second battery unit 42 is not being isolated, the ECU 50 corrects the output limit Wout input in step SI 00 by the output limit correction amount AWout set in step SI 40, corrects the input limit Win input in step SI 00 by the input limit correction amount AWin set in step S I 80, and then once ends the routine (step S220).

[0042] In step S220, a value obtained by subtracting the output limit correction amount AWout set in step S 140 from the output limit Wout input in step S 100 is set as a new output limit Wout, and a value obtained by subtracting the input limit correction amount A Win set in step SI 80 from the input limit Win input in step SI 00 is set as a new input limit Win. Thus, when the output limit correction amount AWout is set to a value (positive value) other than 0 in step SI 40, the output limit Wout is corrected so as to reduce, that is, so as to limit a discharge of the electrical storage device 40 in step S220. In addition, when the input limit correction amount AWin is set to a value (negative value) other than 0 in step S 180, the input limit Win is corrected so as to increase, that is, so as to limit a charge of the electrical storage device 40 in step S220.

[0043] In contrast to this, when it is determined in step SI 90 that the battery isolation flag Fbc is 1 and the first battery unit 41 or the second battery unit 42 is being isolated, the ECU 50 resets each of the output limit correction amount AWout and the input limit correction amount AWin to 0 (step S200), furthermore, the ECU 50 sets all the integral terms of output limit power feedback correction amount AWop, output limit current feedback correction amount AWoi and output limit voltage feedback correction amount AWov and the plurality of input limit power feedback correction amount AWip, input limit current feedback correction amount AWii and input limit voltage feedback correction amount AWiv to 0 (zero clear) (step S210), and then executes the process of step S220, and once ends the routine. Thus, while the first battery unit 41 or the second battery unit 42 is being isolated, the output limit Wout and the input limit Win are not corrected, and the process of step S210 is executed. Thus, all the integral terms of the feedback correction amounts AWop, AWoi, AWov, AWip, AWii, AWiv before the first battery unit 41 or the second battery unit 42 is isolated are not inherited by integral terms after isolation. [0044] As described above, the ECU 50 of the electric vehicle 20 functions as a control unit of the power management device that manages an exchange of electric power between the motor MG or inverter 30, which serves as the power device, and the electrical storage device 40 including the first and second battery units 41 , 42 connected in parallel with each other. When the ECU 50 isolates any one of the first and second battery units 41 , 42 from the other, the ECU 50 sets the output limit correction amount A Wout and the input limit correction amount A Win set as described above to 0 (step S200), and sets the integral terms of the feedback correction amounts AWop, AWoi, AWov, AWip, AWii, AWiv for the output limit Wout and the input limit Win to 0 (step S210). The output limit Wout and the input limit Win serve as parameters for power management. In this way, while the first battery unit 41 or the second battery unit 42 is being isolated or after the first battery unit 41 or the second battery unit 42 has been isolated, the integral terms of the feedback correction amounts AWop, AWoi, AWov, AWip, AWii, AWiv before isolation are not inherited. Thus, it is possible to suppress power management using the output limit Wout and the input limit Win that do not match an actual situation.

[0045] That is, in the electric vehicle 20, failure of power management while the first battery unit 41 or the second battery unit 42 is being isolated is suppressed, and limitation (reduction) of the output limit Wout more than necessary after the first battery unit 41 or the second battery unit 42 has been isolated due to the influence of the integral terms of the feedback correction amounts AWop, AWoi, AWov, AWip, AWii, AWiv accumulated before the first battery unit 41 or the second battery unit 42 is isolated is suppressed. Thus, it is possible to supply a sufficient electric power to the motor MG that is a power supply target of the electrical storage device 40. In addition, in the electric vehicle 20, limitation (increase) of the input limit Win more than necessary after the first battery unit 41 or the second battery unit 42 is isolated due to the influence of the integral terms of the feedback correction amounts AWop, AWoi, AWov, AWip, AWii, AWiv accumulated before the first battery unit 41 or the second battery unit 42 is isolated is suppressed. Thus, it is possible to further properly charge the electrical storage device 40 (the remaining battery unit). Thus, in the electric vehicle 20, it is possible to further properly carry out power management while the first battery unit 41 or the second battery unit 42 is being isolated or after the first battery unit 41 or the second battery unit 42 has been isolated.

[0046] In addition, as in the case of the above-described embodiment, when the torque command Tm* for the motor MG is set to 0 at the time when one of the first battery unit 41 and the second battery unit 42 is isolated from the other, it is possible to isolate the any one of the battery units from the remaining battery unit without shutting down the inverter 30. Thus, insulated gate bipolar transistors (IGBTs), and the like, that have a high breakdown voltage but that are expensive need not be used as the transistors of the inverter 30, so it is possible to reduce the cost of the electric vehicle 20. In this case, current flowing through the motor MG does not always become 0 even when the torque command Tm* for the motor MG is set to 0; however, by setting the integral terms of the feedback correction amounts AWop, AWoi, AWov, AWip, AWii, AWiv at the time when the first battery unit 41 or the second battery unit 42 is isolated to 0, it is possible to appropriately suppress failure of power management due to accumulation of the integral terms even if current flows through the motor MG.

[0047] When any one of the first battery unit 41 and the second battery unit 42 is isolated from the other, in addition to or instead of setting the integral terms of the feedback correction amounts AWoi, AWii, and the like, for the output limit Wout and the input limit Win as the parameters for power management to 0, learning values for power management may be set to 0. Thus, while the first battery unit 41 or the second battery unit 42 is being isolated or after the first battery unit 41 or the second battery unit 42 has been isolated, the learning values before isolation are not inherited. Thus, it is possible to suppress power management using learning values that do not match an actual situation.

[0048] The embodiment of the invention is described on the assumption that the vehicle that is an application target of the invention is the electric vehicle that includes only the motor MG as a drive power generating source; however, the vehicle to which the invention is applied may be, other than the electric vehicle including one or a plurality of motors, a single-motor or double-motor hybrid vehicle that includes an internal combustion engine as a drive power generating source in addition to the motor(s), and may be configured as a so-called plug-in electric vehicle or hybrid vehicle. Furthermore, the electrical storage device 40 may include three or more battery units. In addition, the functions of the ECU 50 may be distributed to a plurality of electronic control units, and power management, such as setting and correcting the above-described output limit Wout and input limit Win may be executed by a single electronic control unit.

[0049] The embodiment of the invention is described above; however, the invention is not limited to the above-described embodiment. The invention may be implemented in various forms without departing from the scope of the invention.

[0050] The invention is applicable to, for example, manufacturing industries of a power management device that manages an exchange of electric power between an electrical storage device and a power device.

Claims

CLAIMS:

1. A power management device comprising:

a control unit configured to manage an exchange of electric power between a power device and an electrical storage device having a plurality of battery units connected in parallel with each other, and configured to set an integral term of a feedback correction amount for a parameter for power management or a learning value for power management to 0 when any one of the plurality of battery units is isolated from the remaining battery unit.

2. The power management device according to claim 1 , wherein the control unit is configured to set an allowable discharge power allowed to be discharged from the electrical storage device, correct the allowable discharge power using a discharge-side feedback correction amount, calculated on the basis of at least a charge/discharge current of the electrical storage device, as an allowable discharge power correction amount, and set the allowable discharge power correction amount to 0 and an integral term of the discharge-side feedback correction amount to 0 when any one of the plurality of battery units is isolated from the remaining battery unit.

3. The power management device according to claim 2, wherein:

the power device includes an electric motor configured to be used as a power source for propelling an electromotive vehicle and an inverter configured to drive the electric motor; and

the control unit is configured to set a torque command for the electric motor to 0 when any one of the plurality of battery units is isolated from the remaining battery unit.

4. The power management device according to any one of claims 1 to 3, wherein the control unit is configured to set an allowable charge power with which the electrical storage device is allowed to be charged, correct the allowable charge power using a charge-side feedback correction amount, calculated on the basis of at least a charge/discharge current of the electrical storage device, as an allowable charge power correction amount, and set the allowable charge power correction amount to 0 and set an integral term of the charge-side feedback correction amount to 0 when any one of the plurality of battery units is isolated form the remaining battery unit.

5. A power management method of managing an exchange of electric power between a power device and an electrical storage device having a plurality of battery units connected in parallel with each other, comprising:

setting an integral term of a feedback correction amount for a parameter for power management or a learning value for power management to 0 when any one of the plurality of battery units is isolated from the remaining battery unit.