JP2011091895A - Power supply control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply control system which quickly and accurately detects the occurrence of a malfunction accompanied by the disconnection of an SMR, and determines whether a starting operation should be executed. <P>SOLUTION: It is determined whether the start of a load should be executed on the basis of a change of the minimum output voltage VL detected by a voltage sensor. When the minimum output voltage VL exceeds a preset value, it is determined that there is no failure, and the connection of the SMR is permitted. When the minimum output voltage VL falls below the preset value, it is determined that there is the failure such as disconnection, and the connection of the SMR is prohibited. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply control system.

  There are vehicles that travel with driving force from one or more motors, such as hybrid vehicles (HV) and so-called electric vehicles (EV). Such a vehicle is generally equipped with a power supply control system including a power supply (battery), and includes a converter that converts the voltage of the power supply to step up and down, and an inverter that converts a DC voltage output from the converter into an AC voltage. Then, electric power is supplied to the motor, and the motor rotates based on the AC voltage output from the inverter to drive the vehicle.

  The motor can also generate an alternating voltage by the braking control of the vehicle and supply it to the inverter. At this time, the inverter converts the AC voltage into the DC voltage, and is charged to the secondary battery after being stepped up and down by the converter as necessary. This secondary battery may be used also as the power source described above, or another secondary battery may be prepared.

  In such a power supply control system, a system main relay (SMR: System Main Relay, hereinafter also referred to as “SMR” or simply “relay”) is provided between the power supply and the converter. The SMR may be welded or disconnected due to, for example, a current flowing through the SMR. If a failure such as welding or disconnection occurs, it may cause a malfunction such as shutting down the power system or switching the power supply.

  In such a power supply control system, it is determined whether or not SMR welding has occurred, and a start operation is executed or prohibited based on this determination (for example, Patent Document 1), and there is a start request. However, it is disclosed that the start of the system is prohibited when normal operation is not ensured (for example, Patent Document 2).

Japanese Patent No. 4259348 Japanese Patent No. 3381708

  The present invention provides a power supply control system that can quickly and accurately detect the occurrence of a problem associated with a disconnection of an SMR and determine whether or not to perform a start-up operation.

  The present invention includes a first relay that switches an electrical connection between one pole of a power source and a load, a second relay that switches an electrical connection between the other pole of the power source and the load, and the first relay A resistor connected in series to the second relay, a third relay connected in parallel to the second relay and the resistor, and switching an electrical connection between the other pole of the power source and the load; and the load A voltage sensor for detecting a voltage that can be supplied from the power source to the load side, and a control unit that controls power supply to the load, wherein the control unit includes the voltage sensor. Is a power supply control system that determines whether or not to execute power supply to the load based on a change in the minimum output voltage detected by.

  According to the present invention, it is possible to promptly and more reliably detect the occurrence of a problem associated with the disconnection of the SMR, and determine whether or not the start operation can be performed.

It is a figure which shows an example of the outline of a structure of the power supply control system in embodiment of this invention. It is a timing chart which shows starting control of the power supply control system in embodiment of this invention. It is a flowchart which shows an example of the control at the time of starting of the conventional power supply control system. It is a timing chart which shows starting control of the conventional power supply control system.

  With reference to FIGS. 3 and 4, an example of control at the time of starting the conventional power supply control system will be described.

  First, an activation request from the user is acquired by turning on the ignition key (IG) (S10). Next, whether or not a failure of at least one of the plurality of SMRs, for example, SMRP, is detected is confirmed based on whether or not a failure signal is acquired from each relay (S12). If a failure signal from the SMR is not detected and it is determined that there is no failure, the activation of the power supply control system is permitted (S16), and power is supplied to the entire system including the converter, inverter, motor, and the like. On the other hand, when the SMR is in a failure state such as disconnection and it is determined that there is a failure by detecting a failure signal, the activation of the power supply control system is prohibited and the activation operation is stopped (S18). As described above, the determination of whether or not the power supply control system can be started is generally performed by determining whether or not there is a failure in the SMR. In order to ensure functional safety earlier, it is generally necessary to make a failure determination in a short time. However, in a power supply control system that makes a startability determination in a short time by such a method, a false detection occurs. There was a possibility.

  In contrast, in the power supply control system according to the embodiment of the present invention, a voltage sensor 22 is provided on the battery 10 side of the converter 16 as shown in FIG. The power supply control system 100 shown in FIG. 1 also includes a battery 10, a converter 16 that steps up and down the voltage of the battery 10, an inverter 18 that converts DC power of the converter 16 into AC power, and AC power supplied from the inverter 18. Motors 20a and 20b that are driven to rotate in response to the control, and a control unit 24. As the battery 10, a secondary battery such as nickel hydride or lithium ion or a fuel cell can be applied, and an assembled battery in which a plurality of batteries are combined may be used as necessary. In other embodiments, only one of the motors 20a and 20b may be provided, or three or more motors may be provided.

  A first relay 12 a (SMRB) is provided between the positive electrode side of the battery 10 and the converter 16. Further, between the negative electrode side of the battery 10 and the converter 16, a second relay 12b (SMRP), a resistor 14 connected in series to the relay 12b, and a second relay 12b and a resistor 14 connected in parallel to the resistor 14 are connected. 3 relays 12c (SMRG).

  The voltage sensor 22 electrically connects the line L1 that electrically connects the first relay 12a (SMRB) and the converter 16, the contact that connects the resistor 14 and the third relay 12c (SMRG), and the converter 16. The minimum output voltage VL with respect to the line L2 to be measured can be measured.

  The control unit 24 is a computer that includes a CPU that performs signal processing therein and a storage unit that stores programs and control data. The converter 16, the inverter 18, the motors 20a and 20b, and the relays 12a, 12b, and 12c are respectively connected to the control unit 24 and configured to operate according to commands from the control unit 24. The voltage sensor 22 is connected to the control unit 24, and the detection signal (minimum output voltage VL) of the voltage sensor 22 is input to the control unit 24. When power supply control system 100 is mounted on an electric vehicle, an ignition key (not shown) that is a switch for starting and stopping the vehicle drive system including power supply control system 100 can be further provided. At this time, the ignition key is connected to the control unit 24, and an ignition key ON / OFF signal is input to the control unit 24.

  As shown in FIG. 2, in this embodiment, instead of directly acquiring the failure detection signal from the SMR, the converter 16, the inverter 18, the motor based on the change in the minimum output voltage VL detected by the voltage sensor 22. It is determined whether or not to supply power to the load including 20a and 20b. More specifically, when the minimum output voltage VL reaches a preset threshold value, it is determined that there is no failure, and SMR connection is permitted. On the other hand, if the minimum output voltage VL does not reach the preset threshold value, it is determined that some failure such as disconnection has occurred, the SMR connection is prohibited, and the activation of the power supply control system 100 is stopped.

  As described above, according to the present embodiment, conflicting demands such as ensuring controllability in a short time and reducing false detection as much as possible can be controlled based on whether or not power can be supplied from the power source to the load. Can be realized simultaneously by determining whether or not to execute.

  Note that the control unit 24 illustrated in FIG. 1 may be configured to acquire a failure detection signal from the SMR in parallel with acquisition of the minimum output voltage VL from the voltage sensor 22. In this embodiment, when it is determined that there is no failure in the SMR from the value of the minimum output voltage VL, when a failure detection signal is acquired from the SMR, for example, in order to further increase the accuracy of the start control, The value of the output voltage VL can be reacquired, and as another embodiment, control for stopping power supply based on detection of a failure detection signal from the SMR can be performed, but the present invention is not limited to these. is not. On the other hand, when it is determined that there is a failure in the SMR from the value of the minimum output voltage VL, if a failure detection signal from the SMR is not detected, the power supply can be restarted to start in the fail safe mode. As yet another embodiment, the fact that the failure detection signal from the SMR has been acquired can be recorded and / or displayed alone or together with the other control described above, but is limited to these embodiments. is not.

  The power supply control system of the present invention can be used by being mounted on an electric vehicle. The term “electric vehicle” as used herein refers to a hybrid electric vehicle, an electric vehicle, a fuel that has a generator that generates electric power by driving or regenerating by an engine, and a motor that operates by electric power from a battery and drives driving wheels. It is intended to include a battery car (FCEV). Further, the present invention is not limited to this, and it may be used by being stationary.

  10 battery, 12a, 12b, 12c relay (system main relay), 14 resistor, 16 converter, 18 inverter, 20a, 20b motor, 22 voltage sensor, 24 control unit.

Claims (1)

A first relay that switches electrical connection between one pole of the power source and the load;
A second relay that switches electrical connection between the other pole of the power source and the load; and a resistor connected in series to the second relay;
A third relay connected in parallel to the second relay and a resistor, and for switching an electrical connection between the other pole of the power source and the load;
A voltage sensor disposed on the power source side of the load for detecting a voltage that can be supplied from the power source to the load side;
A control unit for controlling power supply to the load,
The power supply control system, wherein the control unit determines whether or not to execute power supply to the load based on a change in the minimum output voltage detected by the voltage sensor.

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