JP2006238509A - Control device of electric vehicle, control method of the electric vehicle, program and computer-readable recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine the precharge termination of a capacitor with high accuracy, even if the cycle of a current sensor is short or the accuracy of the current sensor in not sufficient. <P>SOLUTION: This control device of an electric vehicle comprises a battery pack connected to a secondary battery in series thereto; a first contactor connected to one end of the battery pack at its one end; a second contactor connected to the other end of the battery pack at its one end; a series circuit having a third contactor connected to the first contactor, in parallel therewith and a resistor; and a capacitor connected between one end at a side opposite to that of the battery pack of a parallel circuit composed of the first contactor and the series circuit and the other end of the second contactor. The control device also comprises a current-detecting part that detects precharge current in a precharge period, wherein the second and the third contactors are in conductive states, and a determining part that determines the termination of the precharge period, when time rate of change of the precharge current exceeds a reference current change rate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electric vehicle control apparatus, an electric vehicle control method, a program therefor, and a computer-readable recording medium storing the program.

  In recent years, hybrid vehicles (“HEV”: Hybrid Electric Vehicle) and electric vehicles (“PEV”: Pure), in which an assembled battery is mounted as an auxiliary power source in an automobile using an ICE (Internal Combustion Engine) or a fuel cell, etc. Electric vehicles such as electric vehicles are becoming popular.

  The assembled battery usually obtains a desired total voltage by connecting a plurality (for example, 200) of single cells (cells) having an output voltage of about 1.2V in series. In addition, the electric vehicle requires an inverter for driving a traveling motor by converting a direct current power source from the assembled battery into alternating current.

  Between the input terminals of the inverter of the electric vehicle, a large-capacity capacitor that smoothes the fluctuation of the input voltage to the inverter is mounted. When starting the electric vehicle, the ignition key signal is used as a trigger to close the contact of the main contactor that electrically connects and disconnects the battery pack and the inverter to charge the capacitor.

  However, when a capacitor in which the charge is almost empty is charged from an assembled battery that is a direct high-voltage power source, a large current flows at the moment when the contact of the main contactor is about to close. Thereby, there is a possibility that the energized contact of the contactor may be damaged or the contact of the contactor may be welded by being pressurized after the contact is heated and melted.

  Therefore, a method of providing a series circuit of a resistor and a precharge contactor in parallel with the main contactor, and closing the precharge contactor and precharging the capacitor before closing the main contactor is known.

  FIG. 15 shows the operation timing of each contactor when a precharge contactor is used. In FIG. 15, first, at time T0, the ignition key is turned on and the electric vehicle is activated. At time T1 to T2 (period A), only the precharge contactor is turned on, and the welding detection of the low side contactor is performed by comparing the assembled battery voltage and the inverter side voltage. Further, during time T3 to T4 (period B), only the low-side contactor is turned on, and the welding detection of the high-side contactor and the precharge contactor is performed.

  After the welding detection, at times T4 to T5 (period C), both the low-side contactor and the precharge contactor are turned on to start the capacitor precharge. At this time, since a resistor is provided, a large current does not flow through the contact point of the precharge contactor. When precharge is almost finished at time T5, the high-side contactor is turned on and the voltage of the assembled battery is applied.

  According to the above method, by providing a precharge period (period C) in which both the low-side contactor and the precharge contactor are on, the capacitor is precharged (pre-charged) to a certain extent with a limited current through a predetermined resistance. Charge). Thus, when the main contactor is turned on, a large current is prevented from flowing through the contact of the main contactor.

  Patent Document 1 discloses a conventional control apparatus for an electric vehicle that determines the end of the precharge period. Such a control device for an electric vehicle measures the precharge current If when it is estimated that the precharge is almost completed after a predetermined time T has elapsed after the start of the precharge of the capacitor. The measured precharge current If and the reference current value Iref are compared, and if If ≦ Iref, the end of the precharge period is determined.

  In addition, such an electric vehicle control device calculates an integrated value ΣIf of the precharge current If until a predetermined time T elapses after the start of the precharge period in which the capacitor is charged. The calculated integrated value ΣIf of the precharge current If is compared with the current reference integrated value ΣIref, and when ΣIf ≧ ΣIref, the end of the precharge period is determined.

JP-A-10-304501

  However, in recent years, capacitors tend to be made smaller in order to reduce the cost and shorten the time required for precharging. For this reason, the time constant of the precharge current is shortened, and in the electric vehicle control device of the conventional example, it is necessary to make the current sensor current measurement cycle as short as possible in order to reduce the error of the integrated value of the precharge current. . In general, power control of electric vehicles does not require current measurement at such a short cycle, so there is a problem that the circuit and software are complicated and costly only to determine the end of the precharge period. It was.

  In order to reduce the measurement error of the precharge current, it is necessary to use a current sensor with a small current offset error. A general current sensor using a GaAs (gallium arsenide) Hall effect sensor (GaAs Hall sensor) has good magnetic field linearity, but the temperature change of the offset voltage (unbalance potential) large. For this reason, there is a problem in that the accuracy of the sensor cannot be kept stable in the usage environment near the power source of the electric vehicle. Using a highly accurate current sensor is expensive.

  In addition, when calculating the integrated value of the precharge current, it is necessary to set a predetermined time T until the end of the precharge period is determined in consideration of variation in the capacitance of the capacitor and measurement error of the current sensor. is there. Therefore, there is a problem that the precharge period becomes long.

  In view of the above problems, the present invention determines the end of the precharge period with high accuracy even when the current sensor has a short current measurement cycle or when the accuracy of the current sensor is not sufficient, especially without performing precharge for a long period of time. An object of the present invention is to provide an electric vehicle control device, an electric vehicle control method, a program, and a computer-readable recording medium that can reduce the cost and shorten the precharge period.

In order to solve the above problems, the present invention has the following configuration.
The control apparatus for an electric vehicle according to claim 1 is an assembled battery in which one or a plurality of secondary batteries are connected in series, a first contactor in which one end of a contact is connected to one end of the assembled battery, and one end of a contact is connected to the end of the contact. A second contactor connected to the other end of the assembled battery, a third contactor and a series circuit of resistors connected in parallel to the first contactor, and a parallel circuit of the first contactor and the series circuit. A control device for an electric vehicle having a capacitor connected between an end opposite to the assembled battery and the other end of the second contactor, wherein the second contactor and the third contactor In a precharge period in which both contactors are in a conductive state, a current detection unit that detects a precharge current flowing through a conduction path and a time change rate of the precharge current are calculated. Having a termination and determination of the precharge period when above the current rate of change.

  According to the present invention, the second contactor and the third contactor are both in a conducting state, and in the precharge period in which the capacitor is charged, the time change rate of the precharge current flowing through the conduction path is calculated, and the reference current is calculated. The end of the precharge period is determined by comparing with the change rate. As a result, even if the current sensor cycle is short or the accuracy of the current sensor is not sufficient, it is possible to determine the end of the precharge period with high accuracy without performing precharge for a long period of time. An electric vehicle control apparatus that can shorten the period can be realized.

  In the electric vehicle control device according to claim 2, in the electric vehicle control device according to claim 1, the determination unit is detected by the current detection unit after a predetermined time has elapsed from the start of the precharge period. When the first precharge current value is lower than the first reference current value, the high voltage circuit system is determined to be abnormal.

Usually, the precharge current increases rapidly immediately after the start of the precharge period and then gradually decreases. Therefore, if the first precharge current value detected at a timing when the precharge current is considered to be large to some extent is below the first reference current value, an abnormality such as precharge not being performed normally occurs. it seems to do.
The predetermined time is set to be a timing at which the precharge current is considered to be large to some extent.

  According to the present invention, when the first precharge current value detected after the lapse of a predetermined time from the start of the precharge period is lower than the first reference current value, the abnormality of the high voltage circuit system is determined. A highly efficient control device for an electric vehicle can be realized.

  The electric vehicle control device according to claim 3, wherein in the electric vehicle control device according to claim 2, the determination unit determines whether the current after the time change rate of the precharge current exceeds a reference current change rate. When the second precharge current value detected by the detection unit exceeds the second reference current value, the high voltage circuit system abnormality is determined.

  Usually, the precharge current converges to a sufficiently small value after a sufficiently long time has elapsed since the start of the precharge period. Therefore, the time change rate of the precharge current exceeds the reference current change rate, and the second precharge current value detected at the timing when the precharge current is considered to have almost converged exceeds the second reference current value. In this case, it is considered that an abnormality such as an increase in load in the high voltage circuit has occurred.

  According to the present invention, when the second precharge current value detected after the time change rate of the precharge current exceeds the reference current change rate exceeds the second reference current value, the high voltage circuit system It is possible to realize a highly safe control device for an electric vehicle that determines abnormality.

  The electric vehicle control device according to claim 4 is the electric vehicle control device according to claim 1, wherein the second contactor and the third contactor are both in a conductive state. In a certain precharge period, when a current detection unit that detects a precharge current flowing through a conduction path and a time change rate of the precharge current are calculated, and the time change rate of the precharge current exceeds a reference current change rate And detecting a voltage across the capacitor during a precharge period in which both the second contactor and the third contactor are in a conductive state. The time change rate of the voltage across the capacitor and the voltage across the capacitor is calculated, and the time change rate of the voltage across the capacitor is less than the reference voltage change rate. Having a termination and determination of the precharge period when.

  According to the present invention, both the second contactor and the third contactor are in a conductive state, and in the precharge period in which the capacitor is charged, the time change rate of the voltage across the capacitor is calculated and compared with the reference voltage change rate. As a result, the end of the precharge period is determined. This makes it possible to determine the end of the precharge period with high accuracy without performing precharge for a long period of time, regardless of the current sensor cycle or the accuracy of the current sensor, thereby reducing costs and shortening the precharge period. An electric vehicle control device can be realized.

  In the electric vehicle control device according to claim 5, in the electric vehicle control device according to claim 4, the determination unit is detected by the voltage detection unit after a predetermined time has elapsed from the start of the precharge period. When the voltage value across the first capacitor exceeds the first reference voltage value, the high-voltage circuit system is determined to be abnormal.

Usually, since the capacitor is discharged before the precharge is performed, the voltage across the capacitor is zero at the start of the precharge period, and then the voltage across the capacitor gradually increases. Therefore, when the voltage across the first capacitor detected at a timing at which the voltage across the capacitor is not sufficiently increased exceeds the first reference voltage value, the capacitor is not normally discharged. It is considered that an abnormality such as
The predetermined time is set to be a timing at which the voltage across the capacitor is considered not to increase sufficiently.

  According to the present invention, when the voltage value across the first capacitor detected after the elapse of a predetermined time from the start of the precharge period exceeds the first reference voltage value, an abnormality in the high voltage circuit system is determined. A highly safe control device for an electric vehicle can be realized.

  The electric vehicle control device according to claim 6 is the electric vehicle control device according to claim 5, wherein the determination unit is configured such that the time change rate of the voltage across the capacitor is less than a reference voltage change rate. When the voltage value across the second capacitor detected by the voltage detection unit is lower than the second reference voltage value, the high voltage circuit system is determined to be abnormal.

  Usually, the voltage across the capacitor converges to a sufficiently large value after a sufficiently long time has elapsed since the start of the precharge period. Therefore, the time rate of change of the voltage across the capacitor is less than the reference voltage rate of change, and the voltage value across the second capacitor detected at the timing when the voltage across the capacitor has almost converged falls below the second reference voltage value. In such a case, it is considered that an abnormality such as an increase in load in the high voltage circuit has occurred.

  According to the present invention, when the second capacitor voltage value detected after the time change rate of the voltage across the capacitor falls below the reference voltage change rate exceeds the second reference voltage value, the high voltage circuit system Therefore, it is possible to realize a highly safe control device for an electric vehicle.

  In addition, it is possible to realize an electric vehicle control method, a program, and a computer-readable recording medium that have the same effects as described above.

  According to the present invention, even when the current sensor cycle is short or the accuracy of the current sensor is not sufficient, it is possible to determine the end of the precharge period with high accuracy even without performing precharge for a long period of time, thereby reducing the cost. In addition, there is an advantageous effect that an electric vehicle control device, an electric vehicle control method, a program, and a computer-readable recording medium that can shorten the precharge period can be realized.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments that specifically show the best mode for carrying out the present invention will be described below with reference to the drawings.

Embodiment 1
The electric vehicle control apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a configuration of a control device for an electric vehicle according to the present embodiment. In FIG. 1, an electric vehicle control device according to the present embodiment includes an assembled battery 1, a high-side contactor (main contactor) 2, a low-side contactor 3, a precharge contactor 4, a limiting resistor 5, a first capacitor 6, and an inverter 7. A motor generator 8, a current sensor 9, a power supply control unit 10, and a vehicle control unit 11.

  The assembled battery 1 is a power source having a total voltage of 300 V, which is composed of a plurality of battery blocks connected in series. Each battery block is configured by connecting a plurality of secondary batteries having an output voltage of 1.2 V in series. The secondary battery is, for example, a sealed nickel hydride battery (nickel metal hydride battery) excellent in basic characteristics such as energy density, output density, and cycle life, but is not limited to this, but is a lithium ion secondary battery or nickel cadmium. A storage battery, a lead storage battery, or the like may be used.

  One end of the high side contactor 2 is connected to the positive electrode side of the assembled battery 1, and one end of the low side contactor 3 is connected to the negative electrode side. The precharge contactor 4 forms a series circuit together with a limiting resistor 5 (for example, about 10Ω), and this series circuit is connected in parallel with the high side contactor 2.

  The high side contactor 2, the low side contactor 3, and the precharge contactor 4 each have a movable contact and a fixed contact, and further have a coil for operating the movable contact. Each coil has one end connected to the ground potential, and the auxiliary power supply voltage Vsub is applied to the coil via the vehicle control unit 11 to move the movable contact, and switch between a conduction state and a cutoff state between the contacts.

  The first capacitor 6 is a capacitor having a rating of about 2 mF connected between the other end of the high side contactor 2 and the other end of the low side contactor 3. The first capacitor 6 serves to suppress fluctuations in the voltage applied to the inverter 7 and is provided to stably supply the voltage to the motor generator 8.

  The inverter 7 includes a plurality of transistors and diodes capable of high-speed switching, such as an IGBT (Insulated Gate Bipolar Transistor). The inverter 7 converts the input DC power source into AC, and sequentially applies a voltage to each phase of the motor generator 8 to rotationally drive the motor generator 8.

  The motor generator 8 is controlled by the inverter 7 and is driven to rotate when, for example, a magnet embedded in the rotor is given a rotational force by a voltage applied to the stator coil. The motor generator 8 functions as a three-phase AC generator or a three-phase AC motor. The motor generator 8 charges the assembled battery 1 when functioning as a generator, and consumes electric power from the assembled battery 1 when functioning as an electric motor.

  The current sensor 9 detects the current I flowing in the line on the low voltage side of the assembled battery 1 using a Hall sensor that detects an electromagnetic field generated by the current flowing through the conducting wire. The detected current I is converted into an electric signal and then input to the power supply control unit 10.

The vehicle control unit 11 includes a vehicle determination unit 110, a contactor control unit 111, and an inverter control unit 112.
The vehicle determination unit 110 receives an operation signal by an operation of an ignition key, an accelerator, a shift lever, a brake, and the like (not shown) from the operation signal input terminal Op, and according to each signal, the contactor control unit 111, the inverter control unit 112, and the power control An instruction is output to the unit 10.

The contactor control unit 111 controls the conduction state and the cutoff state of the contactors 2 to 4 by applying the auxiliary power supply voltage Vsub to the coils of the high-side contactor 2, the low-side contactor 3, and the precharge contactor 4.
The inverter control unit 112 outputs a signal for controlling the transistor of the inverter 7 based on a voltage applied to the inverter (voltage across the capacitor), a three-phase current signal that is an output signal of the inverter 7, and the like. 7 is used to control the rotational speed of the motor generator 8 and the like.

  The power control unit 10 includes a power determination unit 100, a first multiplexer 101, a second multiplexer 102, a sample switch unit 103, a current detection unit 105, a voltage detection unit 106, a second capacitor 107, and a temperature detection unit 108. .

  The current detection unit 105 reads the current I detected by the current sensor 9 every predetermined current measurement period (for example, every 10 ms) and outputs the current I to the power supply determination unit 100.

The first multiplexer 101 and the second multiplexer 102 are composed of a plurality of switches having one end connected between the battery blocks of the assembled battery 1 and the other end connected to the voltage detection unit 106 via the sample switch unit 103. Is done.
The second capacitor 107 connects between the first multiplexer 101 and the sample switch unit 103 and between the second multiplexer 102 and the sample switch 103.
The sample switch unit 103 includes two switches connected to both ends of the second capacitor 107.
The voltage detection unit 106 measures the voltage across the second capacitor 107 and outputs the voltage to the power supply determination unit 100 when both of the two switches of the sample switch unit 103 are on.

By selecting a switch from each of the first multiplexer 101 and the second multiplexer 102 and turning it on, the second capacitor 107 is charged with the voltage across the battery block of the assembled battery 1. When the two switches of the sample switch unit 103 are turned on, the voltage charged in the second capacitor 107 is detected by the voltage detection unit 106.
The first multiplexer 101, the second multiplexer 102, and the sample switch unit 103 are controlled by the power supply determination unit 100.

  The temperature detection unit 108 detects the temperature of the assembled battery 1 by a temperature sensor such as a thermistor provided in the vicinity of the assembled battery 1. A plurality of temperature sensors may be provided in order to compensate for a temperature difference in the assembled battery 1.

  The power source determination unit 100 inputs the battery block voltage of the assembled battery 1 detected by the voltage detection unit 106, the temperature of the assembled battery 1 detected by the temperature detection unit 108, and the current detected by the current detection unit 105. The state of the assembled battery 1 is monitored from the information. The vehicle control unit 11 performs inverter control and contactor control based on information regarding the state of the assembled battery 1 output from the power supply determination unit 100.

  In addition, the power supply determination unit 100 inputs the current value I from the current detection unit 105 as the precharge current If in the precharge period in which the first capacitor 6 is charged by the precharge contactor 4, and the following equation (1) ) To calculate the time change rate dIf / dt of the precharge current If. When the calculated time change rate dIf / dt of the precharge current If exceeds a predetermined reference current change rate, the end of the precharge period is determined.

In the present embodiment, it is assumed that the predetermined reference current change rate is -0.05. In the following equation (1), the precharge current measured last time is Ifpre, the precharge current measured this time is Ifcur, and the current measurement period of the current sensor 9 is P1.
dIf / dt = (Ifpre-Ifcur) / P1 (1)

  The power supply determination unit 100 is, for example, a microcomputer, and the function of checking the voltage of the battery block and the function of determining the end of the precharge period are executed by a program stored in a computer-readable recording medium.

  Next, the precharge end determination method of the electric vehicle control apparatus according to the present embodiment will be described with reference to FIGS. FIG. 2 is a diagram showing changes in the precharge current If, and FIG. 3 is a diagram showing changes in the temporal change rate dIf / dt of the precharge current If when the current measurement period of the current sensor 9 is 10 ms.

  First, at time 0 ms in FIG. 2, when an ignition key (not shown) is turned on and the electric vehicle is started, the contactor control unit 111 outputs a signal for turning on the low-side contactor 3 and the precharge contactor 4. At time 20 ms, both the low-side contactor 3 and the precharge contactor 4 are turned on, and the first capacitor 6 is charged (precharged) by the precharge contactor 4 with a voltage limited via the limiting resistor 5. Before both the low-side contactor 3 and the precharge contactor 4 are turned on, a period A (a period in which only the precharge contactor 4 is on) and a period B (a period in which only the low-side contactor 3 is on) shown in FIG. Then, welding detection of each of the contactors 2 to 4 may be performed.

  As shown in FIG. 2, the precharge current If rapidly increases at the start time 20 ms of the precharge period. After that, it gradually decreases and eventually converges to zero.

  The power supply determination unit 100 calculates a time change rate dIf / dt of the precharge current If. As shown in FIG. 3, at the start time 20 ms of the precharge period, the time change rate dIf / dt of the precharge current If greatly increases to the plus side. Thereafter, since the precharge current If starts to decrease, the time change rate dIf / dt of the precharge current If falls to the minus side, gradually increases, and eventually converges to almost zero. Note that the current measurement period (10 ms) of the current sensor 9 is long with respect to the rapid change in the precharge current If near the time 20 ms in FIG. Therefore, an error appears in the time change rate dIf / dt of the precharge current If with respect to the precharge current If shown in FIG. However, since the current measurement period (10 ms) of the current sensor 9 is sufficiently short with respect to the assumed precharge period, and a waiting time of 50 ms is provided in step S401 of FIG. The error is negligible.

FIG. 4 is a flowchart illustrating a precharge end determination method performed by the electric vehicle control apparatus according to the present embodiment.
First, both the low-side contactor 3 and the precharge contactor 4 are turned on and precharge is started (S400).

  Next, it is checked whether 50 ms has elapsed from the start of the precharge period (S401), and if it has elapsed, the process proceeds to S402. If 50 ms has not elapsed, the process returns to S401. This is a step provided because the time change rate dIf / dt of the precharge current If once greatly increases to the plus side immediately after the start of the precharge, so that it is not determined that the precharge period has ended due to this increase. Further, since the calculation and comparison of the time change rate dIf / dt of the precharge current If is not performed during the period of S401, it is possible to reduce the memory required for the processing for comparison.

  Next, it is checked whether or not the time change rate dIf / dt of the precharge current If exceeds a predetermined reference current change rate of −0.05 (S402). Since it is thought that it has converged, the high-side contactor 2 is turned on and the precharge is terminated (S403). If dIf / dt is −0.05 or less, the process returns to S402.

  As described above, according to the control apparatus for the electric vehicle of the present embodiment, when the time change rate dIf / dt of the precharge current If exceeds a predetermined reference current change rate in the precharge period, the precharge is performed. It is determined that the period has ended. As a result, even when the current sensor has a short current measurement cycle or when the accuracy of the current sensor is not sufficient, it is possible to determine the end of the precharge period with high accuracy without performing precharge for a long period of time. . Therefore, there is no need to use a high-accuracy current sensor, and there is no need to mount a complicated circuit for detecting a current value in a short cycle, so that the electric vehicle can reduce costs and shorten the precharge period. The control device can be realized.

<< Embodiment 2 >>
With reference to FIGS. 5-7, the control apparatus of the electric vehicle in Embodiment 2 of this invention is demonstrated. FIG. 5 is a block diagram showing the configuration of the control device for the electric vehicle according to the present embodiment. 5 is different from the first embodiment shown in FIG. 1 in that a power supply control unit 50 is provided instead of the power supply control unit 10 and a display output unit 52 is provided. The power supply control unit 50 is different from the power supply control unit 10 of the first embodiment shown in FIG. 1 in that a power supply determination unit 500 is provided instead of the power supply determination unit 100. The other points are the same as those in the first embodiment, and detailed description of elements having the same reference numerals is omitted.

  In the precharge period in which the first capacitor 6 is charged by the precharge contactor 4, the power supply determination unit 500 inputs the current value from the current detection unit 105 as the precharge current If and precharges according to the above equation (1). The time change rate dIf / dt of the current If is calculated. When the calculated time change rate dIf / dt of the precharge current If exceeds a predetermined reference current change rate, the end of the precharge period is determined. In the present embodiment, it is assumed that the predetermined reference current change rate is -0.05. Note that the method for determining the end of the precharge period is the same as in the first embodiment, and thus detailed description thereof is omitted.

  The power source determination unit 500 also compares the first precharge current value If1 input after a predetermined time has elapsed from the start of the precharge period with the first reference current value Iref1. Also, the second precharge current value If2 input after the time change rate dIf / dt of the precharge current If exceeds a predetermined reference current change rate is compared with the second reference current value Iref2. When the comparison result is If1 <Iref1 or If2> Iref2, it is determined that the high voltage circuit system is abnormal, and a display command is output to the display output unit 52.

  The predetermined time is set to be a timing at which the precharge current If is considered to be large to some extent. In the present embodiment, the predetermined time is 30 ms, the first reference current value Iref1 is 5A, and the second reference current value Iref2 is 3A.

  The power supply determination unit 500 is, for example, a microcomputer, and the function of checking the voltage of the battery block, the function of determining the end of the precharge period, and the function of determining an abnormality in the high voltage circuit system are stored in a computer-readable recording medium. It is executed by the programmed program.

  The display output unit 52 is, for example, an LED, a liquid crystal panel, a speaker, and the like. When the abnormality of the high-voltage circuit system is determined by the power supply determination unit 500, the display output unit 52 is notified to the operator of the electric vehicle by display and / or sound. Notify abnormalities.

  Next, the high voltage circuit system abnormality determination method of the electric vehicle control apparatus according to the present embodiment will be described with reference to FIGS. FIG. 6 is a diagram illustrating a change in the normal precharge current If (curve 60) and an abnormal change in the precharge current If (curves 61 and 62).

  First, at time 0 ms in FIG. 6, when an ignition key (not shown) is turned on and the electric vehicle is activated, the contactor control unit 111 outputs a signal for turning on the low-side contactor 3 and the precharge contactor 4. At time 20 ms, both the low-side contactor 3 and the precharge contactor 4 are turned on, and the first capacitor 6 is charged (precharged) by the precharge contactor 4 with a voltage limited via the limiting resistor 5. Before both the low-side contactor 3 and the precharge contactor 4 are turned on, a period A (a period in which only the precharge contactor 4 is on) and a period B (a period in which only the low-side contactor 3 is on) shown in FIG. Then, welding detection of each of the contactors 2 to 4 may be performed.

  As shown in FIG. 6, the precharge current If increases rapidly at the start time 20 ms of the precharge period. After that, it gradually decreases and eventually converges to zero.

  The power source determination unit 500 compares the first precharge current value If1 input after 30 ms, which is a predetermined time from the start of precharge (time 50 ms in FIG. 6), with 5A which is the first reference current value Iref1. . Further, the second precharge current value If2 input after the time change rate dIf / dt of the precharge current If exceeds a predetermined reference current change rate is compared with 3A which is the second reference current value Iref2.

  Since the predetermined time is set to be a timing at which the precharge current If is considered to be large to some extent, if the first precharge current value If1 is less than 5 A, there is an abnormality such as the precharge not being performed normally. It is thought that it has occurred. Further, if the second precharge current value If2 exceeds 3A at the timing when the precharge current If is considered to have almost converged, it is considered that an abnormality such as an increase in load in the high voltage circuit has occurred.

FIG. 7 is a flowchart illustrating a high-voltage circuit system abnormality determination method of the electric vehicle control apparatus according to the present embodiment.
First, both the low-side contactor 3 and the precharge contactor 4 are turned on and precharge is started (S400).

Next, it is checked whether or not 30 ms, which is a predetermined time, has elapsed since the start of the precharge period (S701), and if it has elapsed, the process proceeds to S702. If 30 ms has not elapsed, the process returns to S701.
Next, it is checked whether or not the first precharge current If1 input after 30 ms elapses is less than 5 A which is the first reference current value Iref1 (S702). When the first precharge current If1 is 5 A or more, the process proceeds to S402.

  Next, it is checked whether or not the time change rate dIf / dt of the precharge current If exceeds a predetermined reference current change rate of −0.05 (S402). Since it is considered that it has converged, the process proceeds to S703. If dIf / dt is −0.05 or less, the process returns to S402.

  Next, it is checked whether or not the second precharge current If2 exceeds 3A which is the second reference current value Iref2 (S703), and if it exceeds, the process proceeds to S704. When the second precharge current If2 is 3 A or less, the high side contactor 2 is turned on to end the precharge (S403). In step S <b> 704, the power supply determination unit 500 determines that the high-voltage circuit system is abnormal, and outputs a display that notifies the display output unit 12 of the abnormality.

  According to the flowchart of FIG. 7, the curve 62 in FIG. 6 is determined to be abnormal in the high-voltage circuit system in S702 because the first precharge current If1 falls below 5 A at time 50 ms. Further, a curve 61 in FIG. 6 indicates that the second precharge current If2 exceeds 3 A after the time change rate dIf / dt of the precharge current If exceeds a predetermined reference current change rate, and therefore the high voltage circuit system in S703. Is determined to be abnormal.

  As described above, according to the control device for an electric vehicle of the present embodiment, in the precharge period, the precharge current value is compared with the reference current value after a predetermined time has elapsed since the start of the precharge period. A circuit system abnormality can be determined.

  In the present embodiment, the comparison between the precharge current and the reference current value is performed twice (the comparison between the first precharge current value If1 and the first reference current value Iref1, and the second precharge current). Comparison between the value If2 and the second reference current value Iref2). However, the present invention is not limited to this, and any one comparison may be performed.

<< Embodiment 3 >>
With reference to FIGS. 8 to 11, an electric vehicle control apparatus according to Embodiment 3 of the present invention will be described. FIG. 8 is a block diagram showing the configuration of the control device for the electric vehicle according to the present embodiment. 8 differs from the first embodiment in that a power supply control unit 80 is provided instead of the power supply control unit 10. The power supply control unit 80 is different from the power supply control unit 10 of the first embodiment shown in FIG. 1 in that a power supply determination unit 800 is provided instead of the power supply determination unit 100. The other points are the same as those in the first embodiment, and detailed description of elements having the same reference numerals is omitted.

  In the precharge period in which the first capacitor 6 is charged by the precharge contactor 4, the power source determination unit 800 receives a voltage across the first capacitor 6 (hereinafter, “capacitor across voltage” from the inverter control unit 112 of the vehicle control unit 11. Vc is input every predetermined voltage input period (for example, every 10 ms), and the time change rate dVc / dt of the capacitor both-ends voltage Vc is calculated according to the following equation (2). When the calculated time change rate dVc / dt of the capacitor both-ends voltage Vc falls below a predetermined reference voltage change rate, the end of the precharge period is determined.

In the present embodiment, it is assumed that the predetermined reference voltage change rate is 0.4. In the following equation (2), the voltage across the capacitor detected last time is Vcpre, the voltage across the capacitor detected this time is Vccur, and the voltage input period is P2.
dVc / dt = (Vcpre−Vccur) / P2 (2)

  The power supply determination unit 800 is, for example, a microcomputer, and the function of checking the voltage of the battery block and the function of determining the end of the precharge period are executed by a program stored in a computer-readable recording medium.

  Next, a precharge end determination method of the electric vehicle control apparatus according to the present embodiment will be described with reference to FIGS. FIG. 9 is a diagram showing a change in the capacitor both-ends voltage Vc, and FIG. 10 is a diagram showing a change in the time change rate dVc / dt of the capacitor both-ends voltage Vc when the voltage input period of the power source determination unit 800 is 10 ms. .

  First, at time 0 ms in FIG. 9, when an ignition key (not shown) is turned on and the electric vehicle is started, the contactor control unit 111 outputs a signal for turning on the low-side contactor 3 and the precharge contactor 4. At time 20 ms, both the low-side contactor 3 and the precharge contactor 4 are turned on, and the first capacitor 6 is charged (precharged) by the precharge contactor 4 with a voltage limited via the limiting resistor 5. Before both the low-side contactor 3 and the precharge contactor 4 are turned on, a period A (a period in which only the precharge contactor 4 is on) and a period B (a period in which only the low-side contactor 3 is on) shown in FIG. Then, welding detection of each of the contactors 2 to 4 may be performed.

  As shown in FIG. 9, at the precharge start time 20 ms, the voltage across the capacitor Vc is zero, and then gradually increases until it converges to a predetermined voltage value.

  The power supply determination unit 800 calculates a time change rate dVc / dt of the voltage Vc across the capacitor. As shown in FIG. 10, the time change rate dVc / dt of the capacitor both-ends voltage Vc greatly increases to the plus side after the precharge period start time 20 ms, and thereafter, as the increase in the capacitor both-ends voltage Vc becomes moderate. It gradually decreases and eventually converges to zero. Note that the voltage input period (10 ms) of the power supply determination unit 800 is long with respect to the rapid change in the capacitor-to-capacitor voltage Vc near the time 20 ms in FIG. Therefore, in the vicinity of time 20 ms in FIG. 10, an error appears in the time change rate dVc / dt of the capacitor both-ends voltage Vc with respect to the capacitor both-ends voltage Vc shown in FIG. However, since the voltage input period (10 ms) of the power supply determination unit 800 is sufficiently short with respect to the assumed precharge period, and a waiting time of 50 ms is provided in step S401 of FIG. 11 described in detail below, This error is negligible.

FIG. 11 is a flowchart illustrating a precharge end determination method performed by the control device for an electric vehicle according to the present embodiment.
First, both the low-side contactor 3 and the precharge contactor 4 are turned on and precharge is started (S400).

  Next, it is checked whether 50 ms has elapsed since the start of the precharge period (S401), and if it has elapsed, the process proceeds to S1102. If 50 ms has not elapsed, the process returns to S401. This is a step provided to determine that the precharge period has not ended when the time rate of change dVc / dt of the capacitor both-ends voltage Vc is calculated to be low immediately after the start of precharge. Further, since the calculation and comparison of the time change rate dIf / dt of the precharge current If is not performed during the period of S401, it is possible to reduce the memory required for the processing for comparison.

  Next, it is examined whether or not the time change rate dVc / dt of the capacitor both-ends voltage Vc is lower than 0.4 (S1102). If it is lower, it is considered that the increase in the capacitor both-ends voltage Vc has almost converged. The contactor 2 is turned on to end the precharge (S403). If dVc / dt is 0.4 or more, the process returns to S1102.

  As described above, according to the control apparatus for the electric vehicle of the present embodiment, the time change rate dVc / dt of the voltage Vc across the first capacitor 6 is lower than the predetermined reference voltage change rate during the precharge period. In this case, it is determined that the precharge period has ended. Accordingly, it is possible to determine the end of the precharge period with high accuracy without performing the precharge for a long period of time, regardless of the cycle of the current sensor or the accuracy of the current sensor. Therefore, there is no need to use a high-accuracy current sensor, and there is no need to mount a complicated circuit for detecting a current value in a short cycle, so that the electric vehicle can reduce costs and shorten the precharge period. The control device can be realized.

<< Embodiment 4 >>
With reference to FIGS. 12-14, the control apparatus of the electric vehicle in Embodiment 4 of this invention is demonstrated. FIG. 12 is a block diagram illustrating a configuration of the control device for the electric vehicle according to the present embodiment. 12 is different from Embodiment 3 shown in FIG. 8 in that power supply control unit 120 is provided instead of power supply control unit 80. The power supply control unit 120 is different from the power supply control unit 80 in the third embodiment in that it includes a power supply determination unit 1200 instead of the power supply determination unit 800. The other points are the same as those of the third embodiment, and detailed description of elements having the same reference numerals is omitted.

  In the precharge period in which the first capacitor 6 is charged by the precharge contactor 4, the power source determination unit 1200 receives a voltage across the first capacitor 6 from the inverter control unit 112 of the vehicle control unit 11 (hereinafter referred to as “capacitor across voltage”). ) Vc is input, and the time change rate dVc / dt of the voltage Vc across the capacitor is calculated. When the calculated time change rate dVc / dt of the capacitor both-ends voltage Vc falls below a predetermined reference voltage change rate, the end of the precharge period is determined. In the present embodiment, it is assumed that the predetermined reference voltage change rate is 0.4. Note that the method for determining the end of the precharge period is the same as in the third embodiment, and a detailed description thereof will be omitted.

  In addition, the power source determination unit 1200 compares the first capacitor both-end voltage Vc1 input after a predetermined time has elapsed from the start of the precharge period with the first reference voltage value Vref1. Further, the second capacitor both-end voltage Vc2 inputted after the time change rate dVc / dt of the capacitor both-end voltage Vc falls below a predetermined reference voltage change rate is compared with the second reference voltage value Vref2. When the comparison result is Vf1> Vref1 or Vf2 <Vref2, it is determined that the high voltage circuit system is abnormal, and a display command is output to the display output unit 122.

  The predetermined time is set so that the voltage Vc across the capacitor is considered not to increase sufficiently. In the present embodiment, the predetermined time is 30 ms, and the first reference voltage value Vref1 and the second reference voltage value Vref2 are 250V.

  The power supply determination unit 1200 is, for example, a microcomputer, and the function of checking the voltage of the battery block, the function of determining the end of the precharge period, and the function of determining an abnormality in the high voltage circuit system are stored in a computer-readable recording medium. It is executed by the programmed program.

  The display output unit 122 is, for example, an LED, a liquid crystal panel, a speaker, and the like. When the abnormality of the high-voltage circuit system is determined by the power supply determination unit 1200, the display output unit 122 is notified to the operator of the electric vehicle by display and / or sound. Notify abnormalities.

  Next, the high voltage circuit system abnormality determination method of the electric vehicle control apparatus according to the present embodiment will be described with reference to FIGS. FIG. 13 is a diagram showing a change in the normal capacitor voltage Vc (curve 130) and an abnormal change in the capacitor voltage Vc (curves 131 and 132).

  First, at time 0 ms in FIG. 13, when an ignition key (not shown) is turned on and the electric vehicle is activated, the contactor control unit 111 outputs a signal for turning on the low-side contactor 3 and the precharge contactor 4. At time 20 ms, both the low-side contactor 3 and the precharge contactor 4 are turned on, and the first capacitor 6 is charged (precharged) by the precharge contactor 4 with a voltage limited via the limiting resistor 5. Before both the low-side contactor 3 and the precharge contactor 4 are turned on, a period A (a period in which only the precharge contactor 4 is on) and a period B (a period in which only the low-side contactor 3 is on) shown in FIG. Then, welding detection of each of the contactors 2 to 4 may be performed.

  As shown in FIG. 13, at the precharge start time 20 ms, the voltage Vc across the capacitor is zero, and then gradually increases and eventually converges to a predetermined voltage value.

  The power source determination unit 1200 compares the first capacitor both-end voltage Vc1 input after the elapse of 30 ms, which is a predetermined time from the start of precharge (time 50 ms in FIG. 13), with the first reference voltage value Vref1, 250V. Further, the second capacitor both-ends voltage Vc2 inputted after the time change rate dVc / dt of the capacitor both-ends voltage Vc falls below a predetermined reference voltage change rate is compared with 250 V which is the second reference voltage value Vref2.

  Since the predetermined time is set so that the voltage Vc across the capacitor is not sufficiently increased, if the voltage Vc1 across the first capacitor exceeds 250 V, the first capacitor 6 is normally discharged. It is thought that an abnormality such as not being performed is occurring. Further, if the voltage Vc2 across the second capacitor is less than 250V at the timing at which the voltage Vc across the capacitor has almost converged, it is considered that an abnormality such as an increase in load in the high voltage circuit has occurred.

FIG. 14 is a flowchart for explaining a high-voltage circuit system abnormality determination method of the electric vehicle control apparatus according to the present embodiment.
First, both the low-side contactor 3 and the precharge contactor 4 are turned on and precharge is started (S400).

Next, it is checked whether or not a predetermined time of 30 ms has elapsed since the start of the precharge period (S1401), and if it has elapsed, the process proceeds to S1402. If 30 ms has not elapsed, the process returns to S1401.
Next, it is checked whether or not the first-capacitor both-end voltage Vc1 detected after the elapse of 30 ms exceeds the first reference voltage value Vref1, which is 250V (S1402). When the first capacitor both-ends voltage Vc1 is 250 V or less, the process proceeds to S402.

  Next, it is checked whether or not the time change rate dVc / dt of the capacitor both-ends voltage Vc is lower than a predetermined reference voltage change rate of 0.4 (S1102). Since it is thought that it has been, it progresses to S1403. If dVc / dt is 0.4 or more, the process returns to S1102.

  Next, it is checked whether or not the voltage across the second capacitor Vc2 is lower than 250V which is the second reference voltage value Vref2 (S1403), and if lower, the process proceeds to S1404. When the voltage Vc2 across the second capacitor is 250 V or higher, the high side contactor 2 is turned on and the precharge is terminated (S403). In step S <b> 1404, the power source determination unit 1200 determines that the high-voltage circuit system is abnormal, and outputs a display for notifying the display output unit 122 of the abnormality.

  According to the flowchart of FIG. 14, the curve 132 in FIG. 13 is determined to be abnormal in the high-voltage circuit system in S1402 because the first capacitor across-voltage Vc1 exceeds 250 V at time 50 ms. Further, the curve 131 in FIG. 13 shows that the second capacitor both-end voltage Vc2 falls below 250 V after the time change rate dVc / dt of the capacitor both-end voltage Vc falls below a predetermined reference voltage change rate. It is determined that the system is abnormal.

  As described above, according to the control apparatus for an electric vehicle of the present embodiment, the voltage value across both ends of first capacitor 6 is compared with the reference voltage value after a predetermined time has elapsed since the start of the precharge period. By doing so, it is possible to determine abnormalities in the high voltage circuit system such as an increase in load in the high voltage circuit, in which the first capacitor 6 is not normally discharged.

  In the present embodiment, the comparison between the both-end voltage value of the first capacitor 6 and the reference voltage value is performed twice (the comparison between the first-capacitor both-end voltage value Vc1 and the first reference voltage Vref1, and the first Comparison between the voltage value Vc2 across the capacitor 2 and the second reference voltage value Vref2). However, the present invention is not limited to this, and any one comparison may be performed.

  The present invention can be used as a control device mounted on an electric vehicle such as an electric vehicle and a hybrid vehicle.

The block diagram which shows the structure of the control apparatus of the electric vehicle in Embodiment 1 of this invention. The figure which shows the change of the pre-charge current in Embodiment 1 of this invention. The figure which shows the change of the time change rate of the precharge current in Embodiment 1 of this invention. Flowchart for explaining a precharge end determination method in Embodiment 1 of the present invention The block diagram which shows the structure of the control apparatus of the electric vehicle in Embodiment 2 of this invention. The figure which shows the change of the pre-charge current in Embodiment 2 of this invention. The flowchart explaining the abnormality determination method of the high voltage circuit system in Embodiment 2 of this invention The block diagram which shows the structure of the control apparatus of the electric vehicle in Embodiment 3 of this invention. The figure which shows the change of the capacitor voltage in Embodiment 3 of this invention. The figure which shows the change of the time change rate of a capacitor voltage in Embodiment 3 of this invention. Flowchart for explaining a precharge end determination method in Embodiment 3 of the present invention The block diagram which shows the structure of the control apparatus of the electric vehicle in Embodiment 4 of this invention. The figure which shows the change of the capacitor voltage in Embodiment 4 of this invention. The flowchart explaining the abnormality determination method of the high voltage circuit system in Embodiment 4 of this invention Timing diagram showing the operation of each contactor in an electric vehicle

Explanation of symbols

1 assembled battery 2 high-side contactor (first contactor)
3 Low-side contactor (second contactor)
4 Precharge contactor (third contactor)
DESCRIPTION OF SYMBOLS 5 Limit resistance 6 1st capacitor | condenser 7 Inverter 8 Motor generator 9 Current sensor 10, 50, 80, 120 Power supply control part 11 Vehicle control part 12 Display output part 100, 500, 800, 1200 Power supply control part 101 1st multiplexer 102 Second multiplexer 103 Sample switch unit 105 Current detection unit 106 Voltage detection unit 107 Second capacitor 108 Temperature detection unit 110 Vehicle determination unit 111 Contactor control unit 112 Inverter control unit

Claims (12)

An assembled battery in which one or more secondary batteries are connected in series;
A first contactor having one end of a contact connected to one end of the assembled battery;
A second contactor having one end of a contact connected to the other end of the assembled battery;
A series circuit of a third contactor and a resistor connected in parallel to the first contactor; and
A capacitor connected between the opposite end of the parallel circuit of the first contactor and the series circuit with respect to the assembled battery and the other end of the second contactor;
A control device for an electric vehicle having
A current detection unit that detects a precharge current flowing through a conduction path in a precharge period in which both the second contactor and the third contactor are in a conduction state;
And a determination unit that calculates a time change rate of the precharge current and determines that the precharge period is ended when the time change rate of the precharge current exceeds a reference current change rate. Vehicle control device. The determination unit determines that the high-voltage circuit system is abnormal when a first precharge current value detected by the current detection unit is less than a first reference current value after a predetermined time has elapsed from the start of the precharge period. It is comprised as follows. The control apparatus of the electric vehicle of Claim 1 characterized by the above-mentioned. The determination unit determines a high voltage when a second precharge current value detected by the current detection unit after the time change rate of the precharge current exceeds a reference current change rate exceeds a second reference current value. It is comprised so that it may determine with circuit system abnormality. The control apparatus of the electric vehicle of Claim 2 characterized by the above-mentioned. The electric vehicle control device comprises:
In a precharge period in which both the second contactor and the third contactor are in a conduction state, a current detection unit that detects a precharge current flowing through a conduction path, and a time change rate of the precharge current are calculated, Instead of having a determination unit that determines the end of the precharge period when the time change rate of the precharge current exceeds the reference current change rate,
A voltage detection unit for detecting a voltage across the capacitor in a precharge period in which both the second contactor and the third contactor are in a conductive state;
A determination unit that calculates a time change rate of the voltage across the capacitor and determines that the precharge period ends when the time change rate of the voltage across the capacitor is lower than a reference voltage change rate. The control device for an electric vehicle according to claim 1. The determination unit determines that the high-voltage circuit system is abnormal when a voltage value across the first capacitor detected by the voltage detection unit exceeds a first reference voltage value after a predetermined time has elapsed from the start of the precharge period. It is comprised as follows. The control apparatus of the electric vehicle of Claim 4 characterized by the above-mentioned. The determination unit determines that the voltage value across the second capacitor detected by the voltage detection unit after the time rate of change of the voltage across the capacitor is less than the reference voltage rate of change is below the second reference voltage value. The electric vehicle control device according to claim 5, wherein the electric vehicle control device is configured to determine that the high-voltage circuit system is abnormal. An assembled battery in which one or more secondary batteries are connected in series;
A first contactor having one end of a contact connected to one end of the assembled battery;
A second contactor having one end of a contact connected to the other end of the assembled battery;
A series circuit of a third contactor and a resistor connected in parallel to the first contactor; and
A capacitor connected between the opposite end of the parallel circuit of the first contactor and the series circuit with respect to the assembled battery and the other end of the second contactor;
A method for controlling an electric vehicle having
Detecting a precharge current flowing through a conduction path in a precharge period in which both the second contactor and the third contactor are in a conduction state;
Calculating a time change rate of the precharge current, and comparing the time change rate of the precharge current with a reference current change rate;
Determining the end of the precharge period when the time change rate of the precharge current exceeds the reference current change rate;
A method for controlling an electric vehicle, comprising: A step of determining a high-voltage circuit system abnormality when a first precharge current value detected after a lapse of a predetermined time from the start of the precharge period is lower than a first reference current value;
Determining a high-voltage circuit system abnormality when a second precharge current value detected after a time change rate of the precharge current exceeds a reference current change rate exceeds a second reference current value;
The method for controlling an electric vehicle according to claim 7, further comprising: The method for controlling the electric vehicle is as follows:
Detecting a precharge current flowing through a conduction path in a precharge period in which both the second contactor and the third contactor are in a conductive state; and calculating a time change rate of the precharge current; Comparing the time change rate of the current with the reference current change rate and determining the end of the precharge period when the time change rate of the precharge current exceeds the reference current change rate. Instead of
Detecting a voltage across the capacitor in a precharge period in which both the second contactor and the third contactor are in a conductive state;
Calculating the time change rate of the voltage across the capacitor, and comparing the time change rate of the voltage across the capacitor with a reference voltage change rate;
Determining the end of the precharge period when the time change rate of the voltage across the capacitor is lower than the reference voltage change rate;
The method for controlling an electric vehicle according to claim 7, further comprising: A step of determining a high-voltage circuit system abnormality when a voltage value across the first capacitor detected after a lapse of a predetermined time from the start of the precharge period exceeds a first reference voltage value;
Determining a high-voltage circuit system abnormality when a voltage value across the second capacitor detected after a time rate of change of the voltage across the capacitor falls below a reference voltage rate of change is below a second reference voltage value;
10. The method for controlling an electric vehicle according to claim 9, further comprising:   A program for causing a computer to execute the method for controlling an electric vehicle according to any one of claims 7 to 10.   A computer-readable recording medium storing the program according to claim 11.

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