JP2018061370A - Power supply system control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply system control device which can suppress deterioration in drivability according to cutoff of a relay part.SOLUTION: A battery control part 53 of a control device 50 controls a relay part 15 for switching between permission and prohibition of power supply from a main machine battery 10 which supplies power to a main machine motor 3 serving as a power source of a vehicle 90. A vehicle control part 51 controls a charge state of an auxiliary machine battery 42. The auxiliary machine battery 42 is connected between the main machine battery 10 and the main machine motor 3, and supplies power to a load 45. Before confirmation of abnormality which requires cutoff of the relay part 15 and at a relay off preparation step at which there is the possibility of cutting off the relay part 15, the vehicle control part 51 performs charge amount reduction control for reducing a charge amount of the auxiliary machine battery 42. Thereby, even in the case where the relay part 15 is cut off during regeneration of the main machine motor 3, regenerative drive of the main machine motor 3 can be continued, and deterioration in drivability can be prevented.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power supply system control device.

  2. Description of the Related Art Conventionally, a vehicle control device that suppresses a load dump when a relay is switched from on to off during power generation is known. For example, in Patent Document 1, a DCDC converter is interposed between a low voltage line and a high voltage line. Further, the DCDC converter is operated after the main relay is turned off.

JP2015-119543A

However, in Patent Document 1, if the low voltage battery is in a state near full charge and the main relay is turned off during regeneration of the drive regeneration motor, the low voltage battery cannot fully regenerate power. In this case, since the regeneration is interrupted and the regenerative brake is lost, drivability (hereinafter, “drivability”) may be deteriorated.
This invention is made | formed in view of the above-mentioned subject, The objective is to provide the power supply system control apparatus which can suppress the deterioration of the drivability accompanying interruption | blocking of a relay part.

The power supply system control device of the present invention includes a relay control unit (53) and a charge state control unit (53).
The relay control unit controls the relay unit (15) that switches permission or prohibition of power feeding from the first power source (10) that supplies power to the main motor (3) that is a drive source of the vehicle (90, 190).

The charge state control unit controls the charge state of the second power source (42). The second power source is connected between the first power source and the main motor, and supplies power to the load (45).
The charge state control unit performs charge amount reduction control for reducing the charge amount of the second power source in a relay-off preparation stage before the abnormality is determined to be interrupted and the relay unit may be interrupted.

  In the present invention, in the relay-off preparation stage before the relay unit is turned off, the charge amount of the second power source is reduced in preparation for the case where the relay unit is turned off. Thereby, even when the relay unit is turned off during regeneration of the main motor, the second power source can be charged, so that the regenerative drive of the main motor can be continued and deterioration of drivability can be prevented. it can.

It is a mimetic diagram explaining vehicles by a 1st embodiment of the present invention. It is explanatory drawing explaining the control apparatus by 1st Embodiment of this invention. It is a flowchart explaining charge amount reduction control by 1st Embodiment of this invention. It is a time chart explaining charge amount reduction control by 1st Embodiment of this invention. It is a flowchart explaining charge amount reduction control by 2nd Embodiment of this invention. It is a schematic diagram explaining the vehicle by other embodiment of this invention.

Hereinafter, a power supply system control apparatus according to the present invention will be described with reference to the drawings. Hereinafter, in a plurality of embodiments, the same numerals are given to the substantially same composition, and explanation is omitted.
(First embodiment)
A first embodiment of the present invention is shown in FIGS.
As shown in FIGS. 1 and 2, a control device 50 as a power supply system control device is applied to a vehicle 90. The vehicle 90 of the present embodiment is an EV vehicle that travels with the driving force of the main motor 3. The main motor 3 of the present embodiment is a permanent magnet type synchronous three-phase AC rotating electric machine, and is a so-called “motor generator” having both a function as an electric motor and a function as a generator. Hereinafter, the main motor 3 is appropriately referred to as “MG”.
The main motor 3 is provided with a rotation angle sensor 4 that detects the rotation angle.

  The driving force of the main motor 3 is transmitted to the drive shaft 91. The driving force transmitted to the drive shaft 91 rotates the front wheel 95 which is a drive wheel via the differential gear 92 and the axle 93. Although not shown in FIG. 1, a transmission may be provided between the main motor 3 and the differential gear 92. The transmission may be a continuously variable transmission or a multi-stage transmission.

  The front wheel 95 and the rear wheel 96 are provided with a brake 97. The brake 97 is a friction braking device such as a disc brake. In the present embodiment, the vehicle 90 is braked by the regenerative brake of the main motor 3 and the frictional force of the brake 97. In FIG. 1, in order to avoid complication, the control lines for one brake 97 are shown, and the control lines for the other are omitted.

As shown in FIG. 2, the power supply system 1 includes a main battery 10 as a first power supply, a relay unit 15, an inverter 20, a DCDC converter 41, an auxiliary battery 42 as a second power supply, a load 45, and a control device 50. Etc.
The main battery 10 is a direct current power source constituted by a rechargeable secondary battery such as nickel metal hydride or lithium ion. Main battery 10 is controlled such that the SOC (State Of Charge) is within a predetermined range. The electric power of the main machine battery 10 is mainly supplied to the main machine motor 3 via the inverter 20 and used for driving the main machine motor 3. The main battery 10 is charged with electric power generated by the regeneration of the main motor 3.
In the present embodiment, the main battery 10 has a higher voltage than the auxiliary battery 42. Hereinafter, a configuration from the main battery 10 to the main motor 3 is referred to as a “high voltage system”, and the auxiliary battery 42 and the load 45 are referred to as a “low voltage system”.

Relay unit 15 is provided between main unit battery 10 and inverter 20. The relay unit 15 includes a high potential side relay 16 provided on the high potential side wiring 11 and a low potential side relay 17 provided on the low potential side wiring 12. The high potential side relay 16 and the low potential side relay 17 may be mechanical relays or semiconductor relays.
Relay unit 15 switches between conduction and cutoff between main unit battery 10 and each component of the high voltage system. When the relay unit 15 is turned on, the main battery 10 and the high-voltage components are electrically connected, and when the relay unit 15 is turned off, the main battery 10 and the high-voltage components are shut off.

The inverter 20 includes a drive circuit 21, a capacitor 25, and an MG control unit 52. In the figure, “control unit” is described as “ECU”.
Drive circuit 21 includes a three-phase inverter having six switching elements 211 to 216. The switching elements 211 to 216 are all IGBTs and are provided so as to be able to dissipate heat on both sides. The drive circuit 21 is cooled by an inverter cooler (not shown) through which cooling water circulates.

  The switching elements 211 to 213 connected to the high potential side are connected to the collectors of the switching elements 214 to 216 on the low potential side whose collectors are connected to the high potential side wiring 11 and whose emitters are respectively paired. The emitters of the switching elements 214 to 216 connected to the low potential side are connected to the low potential side wiring 12. The connection points of the paired high potential side switching elements 211 to 213 and the low potential side switching elements 214 to 216 are respectively connected to one end of each phase winding of the main motor 3.

The high-potential-side switching elements 211 to 213 and the low-potential-side switching elements 214 to 216 are alternately and complementarily turned on and off based on the drive signal from the MG control unit 52. The inverter 20 converts the DC power into three-phase AC power by controlling the on / off operation of the switching elements 211 to 216, and outputs it to the main motor 3.
A boost converter (not shown) is provided between the drive circuit 21 and the relay unit 15, and a voltage boosted by the boost converter is applied to the drive circuit 21.
The capacitor 25 is connected to the drive circuit 21 in parallel.

The DCDC converter 41 is connected to the high potential side wiring 11 and the low potential side wiring 12 between the relay unit 15 and the inverter 20. By providing the DCDC converter 41, power can be exchanged between the high voltage system and the low voltage system by voltage transformation. In the present embodiment, the DCDC converter 41 may be a step-down type that steps down a high-voltage voltage, or may be a step-up / step-down type.
The auxiliary battery 42 is a secondary battery such as a lead storage battery and supplies power to the load 45. The load 45 includes a battery blower that cools the main battery 10, an electric power steering device, an air conditioner, and the like. Hereinafter, description will be made assuming that the load 45 is a battery blower.

The control device 50 includes a vehicle control unit 51, an MG control unit 52, a battery control unit 53, a brake control unit 55, and the like. The vehicle control unit 51, the MG control unit 52, the battery control unit 53, and the brake control unit 55 are all composed mainly of a microcomputer or the like. Each process in the vehicle control unit 51, the MG control unit 52, the battery control unit 53, and the brake control unit 55 is a software process in which a CPU stores a program stored in advance in a substantial memory device such as a ROM. There may be hardware processing by a dedicated electronic circuit.
The vehicle control unit 51, the MG control unit 52, the battery control unit 53, and the brake control unit 55 are connected via a vehicle communication network 60 such as a CAN (Controller Area Network), and can exchange information.

The vehicle control unit 51 acquires signals from an accelerator sensor, a shift switch, a brake switch, a vehicle speed sensor, and the like (not shown), and controls the entire vehicle 90 based on the acquired signals. The vehicle control unit 51 calculates a torque command value trq ^* related to driving of the main motor 3 based on the accelerator opening and the vehicle speed SP. Torque command value trq ^* is output to MG control unit 52.
Further, the vehicle control unit 51 controls the charge amount of the auxiliary battery 42 by controlling the driving of the DCDC converter 41 and the load 45. In the present embodiment, the vehicle control unit 51 corresponds to a “charge state control unit”.

The MG control unit 52 controls the driving of the main motor 3 by controlling the on / off operation of the switching elements 211 to 216 based on the torque command value trq ^* and the detection value of the rotation angle sensor 4 and the like. In the present embodiment, driving of the main motor 3 is controlled by current feedback control. Instead of the current feedback control, torque feedback control or the like may be used.

The battery control unit 53 acquires information such as voltage, current, temperature, and SOC of the main battery 10 as main battery information. The battery control unit 53 monitors the state of the main battery 10 so that the SOC of the main battery 10 is within a predetermined range.
Battery control unit 53 determines abnormality of main unit battery 10 based on main unit battery information. When the abnormality of the main unit battery 10 is confirmed, the battery control unit 53 turns off the relay unit 15 and disconnects the main unit battery 10 from the drive circuit 21 and the main unit motor 3.

The abnormality of the main battery 10 includes a voltage abnormality in which the voltage deviates from the normal range, an overcurrent abnormality in which the current exceeds the upper limit value, and an SOC abnormality in which the SOC deviates from the normal range.
Hereinafter, a high voltage abnormality will be described as an example of the abnormality of the main battery 10. In the present embodiment, when the state where the voltage of the main battery 10 exceeds the high voltage abnormality confirmed value Vm_th1 is continued for a predetermined period, the relay unit 15 is turned off as the abnormality confirmed. In this embodiment, the battery control unit 53 governs the on / off control of the relay unit 15 and corresponds to the “relay control unit”.
The brake control unit 55 controls the brake 97.

  By the way, when the abnormality of the main battery 10 is confirmed, the relay unit 15 is cut off in order to prevent thermal runaway of the main battery 10 and the like. If the relay unit 15 is interrupted during regeneration of the main motor 3, current flows through the capacitor 25. Depending on the capacity of the capacitor 25, the high voltage system may become overvoltage. When an overvoltage is applied, stress is applied to components such as the switching elements 211 to 216, the capacitor 25, and the DCDC converter 41. Also, depending on the applied voltage, there is a risk of component failure or the like.

  Further, when the relay unit 15 is turned off during regeneration of the main motor 3, the power generated by regeneration is supplied to the low-voltage system via the DCDC converter 41, so that the voltage increase of the high-voltage system can be suppressed. . However, if the auxiliary battery 42 when the relay unit 15 is turned off is almost fully charged, power cannot be supplied to the low-voltage system, so that regeneration of the main motor 3 needs to be reduced or stopped. When the regeneration of the main motor 3 is reduced or stopped, the regenerative braking force is reduced, and the drivability may be deteriorated.

  Therefore, in the present embodiment, if there is a possibility that the relay unit 15 is to be turned off before the abnormality needs to be turned off, the charge amount of the auxiliary battery 42 is reduced in advance. Prepare for 15 off. Note that “before the abnormality is confirmed and the relay unit 15 may be turned off” means that the relay unit 15 is turned off when the situation deteriorates or continues, and the relay unit 15 is actually turned off. It is undecided whether it will be done.

  The charge state control process of this embodiment is demonstrated based on the flowchart shown in FIG. This process is executed at predetermined intervals by the control device 50 during the period when the start switch of the vehicle 90 is turned on. Hereinafter, “step” in step S101 is omitted, and is simply referred to as “S”. The same applies to the other steps.

  In first S101, the vehicle control unit 51 determines whether or not the vehicle speed SP is greater than the vehicle speed determination value SPth. The vehicle speed determination value SPth is set to a value (for example, 5 [km / h]) at which the main motor 3 is in a regenerative state when the vehicle 90 decelerates. When it is determined that the vehicle speed SP is equal to or less than the vehicle speed determination value SPth (S101: NO), the charge amount reduction control is not performed. When it is determined that the vehicle speed SP is greater than the vehicle speed determination value SPth (S101: YES), the process proceeds to S102.

In S102, the vehicle control unit 51 determines whether or not the main motor 3 is being regenerated. In the present embodiment, it is determined that the main motor 3 is being regenerated when the accelerator opening is decreased or when the accelerator pedal is in an OFF state. Whether or not regeneration is in progress may be determined based on the torque command value trq ^* . When it is determined that the main motor 3 is not being regenerated (S102: NO), the charge amount reduction control is not performed. When it is determined that the main motor 3 is being regenerated (S102: YES), the process proceeds to S103.

  In S103, the vehicle control unit 51 determines whether or not the charge amount of the auxiliary battery 42 is larger than the auxiliary device charge amount threshold Vs_th. The auxiliary machine charge amount threshold Vs_th is set to a value that can cover the power used by the load 45. The auxiliary device charge amount threshold Vs_th may be variable according to the power usage state in the load 45. When it is determined that the charge amount of the auxiliary battery 42 is equal to or less than the auxiliary device charge amount threshold Vs_th (S103: NO), the charge amount reduction control is not performed. When it is determined that the charge amount of the auxiliary battery 42 is greater than the auxiliary charge amount threshold value Vs_th (S103: YES), the process proceeds to S104.

  In S104, the vehicle control unit 51 determines whether it is a relay-off preparation stage in which the relay unit 15 may be turned off. In the present embodiment, the voltage of the main unit battery 10 is acquired from the battery control unit 53, and when the voltage of the main unit battery 10 is higher than the relay-off preparation value Vm_th2, which is a value smaller than the high-voltage abnormality determination value Vm_th1, to decide. When it is determined that it is not the relay-off preparation stage (S104: NO), the charge amount reduction control is not performed. When it is determined that it is in the relay-off preparation stage (S104: YES), the process proceeds to S105.

  In S105, the vehicle control unit 51 performs charge amount reduction control. Specifically, by driving the battery blower that is the load 45 to the maximum, the power of the auxiliary battery 42 is consumed, and the charge amount of the auxiliary battery 42 is reduced. Further, the DCDC converter 41 is driven, and electric power generated by regeneration of the main motor 3 is supplied to the low-voltage system via the DCDC converter 41. Since S105 is a process before the relay unit 15 is turned off, it is not necessary to supply all the regenerative power to the low voltage side, and depending on the state of the main battery 10 and the auxiliary battery 42, the main battery 10 side The amount of power to be regenerated and the amount of power to be regenerated on the auxiliary battery 42 side can be changed as appropriate.

In S106, the battery control unit 53 determines whether or not the relay unit 15 has been turned off. In the present embodiment, when the voltage of the main battery 10 is higher than the high voltage abnormality determination value Vm_th1 for a predetermined period, the relay unit 15 is determined to be off. When it is determined that the relay unit 15 is not turned off (S106: NO), the processing of S107 and S108 is not performed. When it is determined that the relay unit 15 is turned off (S106: YES), the process proceeds to S107.
In S107, the battery control unit 53 turns off the relay unit 15.
In S108, the vehicle control unit 51 continues to drive the DCDC converter 41 and continues to supply the regenerative power of the main motor 3 to the low-voltage system. Further, after the relay unit 15 is turned off, the process proceeds to a separate fail-safe process.

The charge state control process of this embodiment is demonstrated based on the time chart of FIG. In FIG. 4, the horizontal axis is the common time axis, (a) is the vehicle speed, (b) is the accelerator opening, (c) is the brake switch, (d) is the voltage of the main battery 10, and (e) is the relay unit 15. (F) is the operating state of the battery blower, (g) is the driving state of the DCDC converter 41, (h) is the regenerative amount of the main battery 10, (i) is the regenerative braking amount, and (j) is the auxiliary device. The amount of charge of the battery 42 is shown. In FIG. 4, the time scale and the like are appropriately changed for convenience of explanation.
The steady state BLa of the battery blower shown in FIG. 4 (f) is a state corresponding to a state such as the temperature of the main battery 10 and may be in a stopped state. In FIG. 4G, the state where the DCDC converter 41 is stopped is described as “0”, and the state where the DCDC converter 41 is driven is described as “1”.

  At time x1, the voltage of main unit battery 10 becomes greater than relay-off preparation value Vm_th2. Relay off ready value Vm_th2 is smaller than high voltage abnormality confirmed value Vm_th1, and even if the voltage of main battery 10 is equal to or higher than relay off ready value Vm_th2, relay unit 15 is not turned off if it is less than high voltage abnormality confirmed value Vm_th1. . Further, at time x1, since the accelerator opening is not 0 and the vehicle is accelerating, the charge amount reduction control is not performed.

  At time x2, the accelerator opening is zero, and the main motor 3 is in a regenerative state. At this time, the charge amount of the auxiliary battery 42 is larger than the auxiliary device charge amount threshold Vs_th. Further, since the voltage of the main battery 10 is larger than the relay-off preparation value Vm_th2 and there is a possibility of relay-off when a further voltage increase occurs, it is regarded as a relay-off preparation stage.

  In the present embodiment, when the main motor 3 is being regenerated, the charge amount of the auxiliary battery 42 is larger than the auxiliary charge amount threshold value Vs_th, and it is predicted that the relay unit 15 may be turned off. 4 (f) and 4 (g), the DCDC converter 41 is driven and the driving state of the battery blower is changed from the steady state BLa to the maximum driving state BLmax. Thereby, as shown in FIG.4 (j), the charge amount of the auxiliary battery 42 falls.

  When the state in which the voltage of the main battery 10 exceeds the high voltage abnormality determined value Vm_th1 continues for a predetermined period at time x3, the relay unit 15 is turned off. In FIG. 4, the description about the continuation of the predetermined period is omitted, and the relay unit 15 is described as being turned off when the voltage of the main battery 10 exceeds the high voltage abnormality determined value Vm_th1.

The regenerative power from the main motor 3 is normally charged in the main battery 10. In addition, if the relay unit 15 is turned off during regeneration of the main motor 3, power cannot be supplied to the main battery 10 side. At this time, if there is a margin in the charge amount of the auxiliary battery 42, the regenerative power of the main motor 3 can be charged to the auxiliary battery 42 by driving the DCDC converter 41.
However, as in the reference example indicated by the alternate long and short dash line, when the auxiliary battery 42 is nearly fully charged, the regenerative power of the main motor 3 cannot be charged to the auxiliary battery 42. Therefore, as shown in FIGS. 4H and 4I, the main motor 3 cannot be regeneratively driven, and the regenerative brake amount becomes zero. If the amount of regenerative braking decreases rapidly, the user may feel the vehicle jumping out and the dribbling may be deteriorated.
As a reference example, when the DCDC converter 41 is not driven before the relay unit 15 is turned off, the start of power supply to the low-voltage system is delayed, which may cause overvoltage in the high-voltage system.

  Therefore, in the present embodiment, when there is a possibility that the relay unit 15 may be turned off, the DCDC converter 41 is driven in advance and the load 45 (using the power of the auxiliary battery 42) is used regardless of whether the relay unit 15 is actually turned off. In the example of FIG. 4, the amount of charge of the auxiliary battery 42 is reduced by consuming the electric power of the auxiliary battery 42 by the battery blower). As shown in FIG. 4 (i), when the relay unit 15 is turned off during regeneration of the main motor 3 at time x3, the electric power generated by the regenerative drive of the main motor 3 is supplied to the low-voltage system, and the auxiliary battery 42 is charged. Thereby, the equivalent regenerative braking force can be maintained before and after the relay unit 15 is turned off, and the deterioration of drivability can be prevented. Further, by supplying the regenerative power of the main motor 3 to the low-voltage system, it is possible to prevent the occurrence of load dump in the high-voltage system.

When the brake switch is turned on by a brake operation by the driver at time x4, the regenerative drive of the main motor 3 is terminated, and the vehicle 90 is decelerated and stopped by the braking force of the brake 97.
In FIG. 4, the charge amount of the auxiliary battery 42 is in a state close to full charge at time x <b> 4, but in reality, the charge amount according to the power consumption amount, the regeneration amount, and the like at the load 45. Further, although the regenerative brake amount is constant from time x3 to time x4, the regenerative brake amount may be gradually reduced in cooperation with the brake 97.

  In the example of FIG. 4, at time x1, the voltage continues to rise after the voltage of the main battery 10 exceeds the relay-off preparation value Vm_th2, exceeds the high-voltage abnormality determined value Vm_th1, and the relay unit 15 is turned off. On the other hand, when the voltage of the main unit battery 10 exceeds the relay-off preparation value Vm_th2 is temporary and the voltage of the main unit battery 10 starts to decrease and becomes lower than the relay-off preparation value Vm_th2, or the power running of the main unit motor 3 When the state is reached, the charge amount reduction control is terminated. Specifically, the driving state of the battery blower is returned to the steady state BLa. The DCDC converter 41 may be stopped simultaneously with the end of the charge amount reduction control, or may be stopped after increasing the charge amount of the auxiliary battery 42.

As described above, the control device 50 according to the present embodiment includes the battery control unit 53 and the vehicle control unit 51.
The battery control unit 53 controls the relay unit 15 that switches permission or prohibition of power supply from the main unit battery 10 that supplies power to the main unit motor 3 that is a power source of the vehicle 90.
The vehicle control unit 51 controls the charging state of the auxiliary battery 42. The auxiliary battery 42 is connected between the main battery 10 and the main motor 3 and supplies power to the load 45.
The vehicle control unit 51 performs charge amount reduction control for reducing the charge amount of the auxiliary battery 42 in a relay-off preparation stage where there is a possibility that the relay unit 15 may be cut off before the abnormality that requires the relay unit 15 to be cut off. Do.

  When the relay unit 15 is turned off, power cannot be transferred between the main motor 3 and the main battery 10. When the main motor 3 is being regenerated and the auxiliary battery 42 has a large amount of charge and regenerative power cannot be supplied to the low voltage side, the regeneration of the main motor 3 must be stopped. If the regeneration of the main motor 3 is stopped as the relay unit 15 is turned off, the amount of regenerative braking is reduced, and the drivability may be deteriorated.

  Therefore, in the present embodiment, the charge amount of the auxiliary battery 42 is reduced in preparation for the case where the relay unit 15 is turned off in the relay-off preparation stage before the relay unit 15 is turned off. Thereby, even if the relay unit 15 is turned off during regeneration of the main motor 3, the regenerative power can be supplied to the low voltage system via the DCDC converter 41 and the auxiliary battery 42 can be charged. The regenerative drive of the main motor 3 can be continued, and the deterioration of drivability can be prevented. Further, by supplying the regenerative power of the main motor 3 to the low voltage system, it is possible to suppress the occurrence of overvoltage in the high voltage system.

The vehicle control unit 51 consumes the power of the auxiliary battery 42 by the battery blower as the load 45 in the charge amount reduction control. Thereby, the charge amount of the auxiliary battery 42 can be appropriately reduced.
The auxiliary battery 42 is connected between the main battery 10 and the main motor 3 via the DCDC converter 41. The vehicle control unit 51 drives the DCDC converter 41 in the charge amount reduction control. Thereby, when the relay unit 15 is turned off during regeneration of the main motor 3, the regenerative power of the main motor 3 can be supplied to the low-voltage system without delay, and the occurrence of overvoltage can be suppressed.

  The vehicle control unit 51 performs charge amount reduction control when the main motor 3 is being regenerated. In other words, if the main motor 3 is in power running, even if the relay unit 15 is turned off, the deterioration of the drivability associated with the decrease in the regenerative brake amount does not occur. Do not do. Thereby, the deterioration of the drivability when the relay part 15 is turned off can be suppressed.

  The vehicle control unit 51 performs charge amount reduction control when the charge amount of the auxiliary battery 42 is equal to or greater than a predetermined amount. In other words, if the charge amount of the auxiliary battery 42 is less than the predetermined amount, the charge amount reduction control is not performed. As a result, the charge amount of the auxiliary battery 42 can be appropriately reduced in preparation for turning off the relay unit 15 while leaving the minimum charge amount necessary for driving the load 45.

(Second Embodiment)
A second embodiment of the present invention is shown in FIG.
In this embodiment, a step-up / step-down type is used as the DCDC converter 41.
The charge amount reduction control of this embodiment will be described based on the flowchart shown in FIG. In the present embodiment, S114 and S115 are added to the processing in the first embodiment.

  The main motor 3 is being regenerated (S102: YES), the charge amount of the auxiliary battery 42 is larger than the auxiliary device charge amount threshold Vs_th (S103: YES), and the relay unit 15 may be turned off. In S <b> 114 that shifts to (S <b> 104: YES), the battery control unit 53 determines whether or not the main battery 10 can be charged. In the present embodiment, based on the SOC of the main battery 10, it is determined that charging is possible when the SOC of the main battery 10 is equal to or less than a determination threshold. When it is determined that the main unit battery 10 cannot be charged (S114: NO), that is, when the SOC of the main unit battery 10 is larger than the determination threshold value, the process proceeds to S105 and the charge amount reduction control similar to that of the first embodiment is performed. . When it is determined that the main battery 10 can be charged (S114: YES), the process proceeds to S115.

  In S115, the vehicle control unit 51 performs charge amount reduction control. In the present embodiment, the DCDC converter 41 is driven so as to boost the voltage of the low voltage system, the power of the auxiliary battery 42 is supplied to the high voltage system, and the main battery 10 is charged. Reduce. Thereby, the loss of electric power can be reduced.

In the present embodiment, the vehicle control unit 51 supplies the power of the auxiliary battery 42 to the main battery 10 in the charge amount reduction control. Thereby, the charge amount of the auxiliary battery 42 can be appropriately reduced while reducing power loss.
In addition, the same effects as those of the above embodiment can be obtained.

(Other embodiments)
(A) Charge Reduction Process In the above embodiment, it is determined whether or not the motor generator is being regenerated. If the motor generator is not regenerating, the charge quantity reduction control is not performed. In another embodiment, the determination process of S102 may be omitted, and the charge amount reduction control may be performed even when the motor generator is in power running. Similarly, the determination process in S101 may be omitted. Moreover, the processing order of S101 to S104 may be changed.

In the above embodiment, when the voltage of the main unit battery is higher than the relay-off preparation value, it is determined that the relay-off preparation stage in which the relay unit may be turned off. In another embodiment, when the voltage of the main battery is lower than the low-voltage side relay-off preparation value set to a value higher than the low-voltage abnormality determination threshold, it may be determined that the relay-off preparation stage is in progress.
In another embodiment, assuming that the voltage of the main engine battery exceeds the high voltage abnormality confirmed value and the relay unit is turned off after a lapse of a predetermined time, the voltage exceeding the high voltage abnormality confirmed value is first detected. May be determined to be in the relay-off preparation stage. The same applies to the low pressure abnormality.

  In another embodiment, instead of the voltage of the main battery, when the current, temperature, or SOC of the main battery becomes a temporary abnormal state, it may be determined that the relay-off preparation stage is in progress. In the temporary abnormality state, since the abnormality is not confirmed, the relay unit is not turned off. In addition, as in the case of voltage, when an abnormality is confirmed when a state that exceeds the determination value related to the determination of abnormality is continued for a predetermined period, the first value that exceeds the determination value related to the determination of abnormality determination You may judge from the time of a detection that it is a relay-off preparation stage.

  In another embodiment, when the relay unit is turned off due to an abnormality of a component other than the main unit battery, when the component that triggers the relay unit off is in a temporary abnormal state, the relay off preparation stage may be determined. . Examples of components that can trigger the relay unit off include a DCDC converter, a main motor, and an inverter. In another embodiment, when the temperature of the switching element of the motor generator or the circuit unit is out of a predetermined range, it may be determined that the relay-off preparation stage is in progress.

In another embodiment, the relay-off preparation stage may be determined based on the external environmental state of the vehicle.
For example, when the vehicle is traveling on a rough road, it may be determined that it is in a relay-off preparation stage. This is because, when traveling on a rough road, the holding power of the relay unit is reduced, and the relay unit may be turned off unintentionally. Further, when traveling on a rough road, the relay unit may be turned off due to an erroneous determination due to a decrease in detection performance of various sensors and an increase in detection error. The determination as to whether or not the vehicle is traveling on a rough road may be made based on a detection value of a G sensor or a yaw rate sensor mounted on the vehicle, or may be made based on navigation information.
Further, when the vehicle is traveling in an environment with a lot of electromagnetic noise such as in a tunnel, it may be determined that it is in a relay-off preparation stage. This is because if there is a lot of electromagnetic noise, the detection performance of various sensors will deteriorate, and the relay unit may be turned off due to erroneous determination accompanying an increase in detection error.

For example, when the external pressure of the vehicle is low, or when the vehicle is traveling at a high altitude, it may be determined that the relay-off preparation stage is in progress. This is because abnormalities are likely to occur in a state where the atmospheric pressure such as high altitude is lowered, and the relay unit may be turned off.
Further, when the outside air temperature of the vehicle is out of the predetermined range, it may be determined that the relay is off. This is because the battery is vulnerable to cold and intense heat, and the relay unit may be turned off with an increase in SOC calculation error.

  In the first embodiment, in the charge amount reduction control, the charge amount of the second power source is reduced by maximally driving the battery blower. In another embodiment, the driving of the battery blower is not limited to the maximum driving, and any driving state may be used as long as the charge amount of the second power source can be reduced. Moreover, you may make it reduce the charge amount of a 2nd power supply with loads other than a battery blower by charge amount reduction control. Further, the charge amount of the second power source may be reduced by a plurality of loads.

(A) Control Device In the above embodiment, the control device includes four ECUs, that is, a vehicle control unit, an MG control unit, a battery control unit, and a brake control unit. In other embodiments, the number of ECUs constituting the control device may be three or less, or five or more. In addition, as long as each ECU can exchange information by communication or the like, each process related to the charge amount reduction control may be performed by any ECU.

(C) Main motor In the above embodiment, the main motor is a permanent magnet type three-phase AC rotating electric machine. In other embodiments, any main motor may be used.
(D) Power source In the above embodiment, the first power source is a secondary battery such as nickel metal hydride or lithium ion, and the second power source is a secondary battery such as a lead storage battery. In other embodiments, any type of secondary battery may be used as the first power source and the second power source, or an electric double layer capacitor or the like may be used. In the above embodiment, the first power supply is higher in voltage than the second power supply. In other embodiments, the voltage of the second power source does not necessarily have to be lower than the voltage of the first power source.

(E) Vehicle In the above embodiment, the vehicle to which the power supply system control device is applied is an EV vehicle that travels using the power of one main motor. In other embodiments, a plurality of main motors may be provided. In another embodiment, the vehicle to which the power supply system control device is applied is not limited to an EV vehicle, but may be a hybrid vehicle including an engine in addition to a main motor as a drive source of the vehicle. In another embodiment, for example, a fuel cell vehicle 190 as shown in FIG. 6 may be used. The fuel cell vehicle 190 is equipped with an H ₂ tank 191 and a fuel cell stack 192, and the electric power generated by the fuel cell stack 192 is supplied to the inverter 20.
In the above embodiment, the vehicle is a front wheel drive vehicle. In other embodiments, the vehicle may be a rear wheel drive vehicle or a four wheel drive vehicle.
As mentioned above, this invention is not limited to the said embodiment at all, In the range which does not deviate from the meaning of invention, it can implement with a various form.

3 ... Main machine motor 10 ... Main machine battery (first power supply)
15 ... Relay unit 41 ... DCDC converter 42 ... Auxiliary battery (second power supply)
45 ... Load 50 ... Control device (Power supply system control device)
51 ... Vehicle control unit (charge state control unit)
53 ... Battery control unit (relay control unit)
90, 190 ... vehicle

Claims (6)

Relay control unit (53) for controlling the relay unit (15) for switching permission or prohibition of power feeding from the first power supply (10) that supplies power to the main motor (3) that is a power source of the vehicle (90, 190). When,
A charge state control unit (51) for controlling a charge state of a second power source (42) connected between the first power source and the main motor and supplying power to a load (45);
With
The charge state control unit is a charge amount reduction control that reduces the charge amount of the second power source in a relay-off preparation stage before the abnormality determination that requires the relay unit to be interrupted and in which the relay unit may be interrupted. Power supply system control device.   The power supply system control device according to claim 1, wherein the charge state control unit causes the load to consume power of the second power supply in the charge amount reduction control. The second power source is connected between the first power source and the main motor via a DCDC converter (41).
The power supply system control device according to claim 1, wherein the charge state control unit drives the DCDC converter in the charge amount reduction control.   The power supply system control device according to claim 1, wherein the charge state control unit supplies power of the second power supply to the first power supply in the charge amount reduction control.   The said charge condition control part is a power supply system control apparatus as described in any one of Claims 1-4 which performs the said charge amount reduction control, when the said main motor is in regeneration.   The power supply system control device according to any one of claims 1 to 5, wherein the charge state control unit performs the charge amount reduction control when a charge amount of the second power source is equal to or greater than a predetermined amount.

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