JP4567711B2 - Electric car - Google Patents

Description

  The present invention relates to an electric vehicle.

Conventionally, there is a drive system including a battery as a power source of an electric vehicle. This drive system includes, for example, a motor that drives a vehicle, and an inverter that converts DC power supplied from the battery into AC power and supplies the AC power to the motor in addition to the battery.
According to this electric vehicle, the motor is driven by converting the DC power from the battery into AC power by the inverter and supplying the AC power to the motor.

  Here, in order to drive the motor, it is necessary to supply high voltage DC power to the inverter. Thus, a method has been proposed in which a step-up DC / DC converter is provided between the battery and the inverter to step up the voltage of the DC power from the battery (see, for example, Patent Document 1). In this method, a line that passes through the step-up DC / DC converter or a line that does not pass through the step-up DC / DC converter is switched in accordance with the traveling state.

  According to this proposal, since the power from the battery is boosted by the step-up DC / DC converter, high-voltage AC power can be supplied to the motor without increasing the voltage of the battery. Further, since the current of AC power supplied to the motor can be reduced, heat generation due to the internal resistance of the wiring from the battery to the motor can be suppressed.

  In addition, a current containing a lot of harmonic components may flow through the input terminal of the inverter, but a current containing a lot of harmonic components cannot flow through the battery. Thus, a method of connecting a smoothing capacitor in parallel with the inverter has been proposed (see, for example, Patent Document 2).

  According to this proposal, the voltage waveform can be smoothed by the smoothing capacitor, and the harmonic component can be removed from the current flowing through the battery. In addition, precharging the smoothing capacitor can prevent an inrush current from becoming excessive.

Thus, the drive system is provided with a step-up DC / DC converter and a smoothing capacitor. In this drive system, the voltage of the smoothing capacitor is detected by a voltmeter, and when the voltage of the smoothing capacitor becomes substantially equal to the voltage of the battery, it is determined that the precharge of the smoothing capacitor has been completed normally, and the driving of the motor is started.
JP 2004-364485 A JP-A-6-46507

  However, if the voltmeter that detects the voltage of the smoothing capacitor fails, even if the precharging of the smoothing capacitor is completed normally, it cannot be detected that the precharging is completed normally, and the motor drive may not be started. It was.

  An object of the present invention is to provide an electric vehicle that can determine whether or not charging of a smoothing capacitor has been normally completed without detecting the voltage of the smoothing capacitor with a voltmeter.

  The electric vehicle according to the present invention includes a motor for driving the vehicle (for example, a motor 90 described later), a power source for outputting DC power (for example, a battery 30 described later), and a first smoothing capacitor (for example, a first smoothing capacitor described later). And a second smoothing capacitor (for example, a smoothing capacitor to be described later) and a boosting means (for example, a DC / DC converter 50 to be described later) and a second smoothing capacitor (for example, a smoothing capacitor to be described later). 81), and converts the DC power boosted by the boosting means into AC power and supplies it to the motor (for example, an inverter 70 described later), the first smoothing capacitor, and the second Capacitor charging means for charging the smoothing capacitor (for example, precharge described later) and power supply voltage detecting means for detecting the voltage of the power supply (for example, A voltmeter 45 described later, a motor-side voltage detecting means (for example, a voltmeter 82 described later) for detecting a voltage on the motor side from the boosting means, and a voltage of the power source detected by the power supply voltage detecting means, And charging completion determining means (for example, determining whether or not charging of the first smoothing capacitor is normally completed based on the voltage on the motor side from the boosting means detected by the motor side voltage detecting means) And a control device 5) to be described later, wherein the charging completion determining means is such that the voltage value of the motor side voltage detecting means before charging is lower than the voltage value of the power supply voltage detecting means by a predetermined voltage. If the difference between the voltage value of the motor side voltage detection means after charging and the voltage value of the power supply voltage detection means after charging is within a predetermined range, it is determined that the charging has been completed normally. Special To.

  According to the present invention, the electric vehicle has a motor side voltage detecting means for detecting a motor side voltage from the boosting means, a voltage value detected by the motor side voltage detecting means, and a voltage value detected by the power supply voltage detecting means. Charging completion determining means for determining whether or not the charging of the first smoothing capacitor has been normally completed on the basis thereof. When the voltage of the first smoothing capacitor changes, the voltage on the motor side from the boosting means changes accordingly. Therefore, the first smoothing capacitor can be charged without using the means for detecting the voltage of the first smoothing capacitor. It can be determined whether or not is completed normally.

In addition, the following two conditions were provided as conditions for determining by the charging completion determining means that the charging of the first smoothing capacitor was normally completed. The first condition is that the voltage value detected by the motor-side voltage detection means is equal to or lower than a value lower by a predetermined voltage than the voltage value detected by the power supply voltage detection means in a state before charging the first smoothing capacitor. . The second condition is that the difference between the voltage value detected by the motor side voltage detection means and the voltage value detected by the power supply voltage detection means is within a predetermined range in the state after the first smoothing capacitor is charged. It is.
Therefore, in the state before charging the first smoothing capacitor, the voltage at the time of the previous start remains on the motor side from the boosting means, and the voltage value detected by the motor side voltage detecting means is the voltage value detected by the power supply voltage detecting means. If the value is larger than the value lower than the predetermined voltage, the first condition described above is not satisfied. Therefore, in the state before charging the first smoothing capacitor, even if the voltage at the time of the previous start remains on the motor side from the boosting means, it is mistakenly assumed that the charging of the first smoothing capacitor has been completed normally. Discrimination can be prevented.

  In this case, it further includes a charge start determining means (for example, a control device 5A described later) for determining the start timing of charging by the capacitor charging means, and the charge start determining means is configured such that the voltage value of the motor side voltage detecting means is It is preferable that the charging start time by the capacitor charging means is after the voltage value of the power supply voltage detecting means is lower than a predetermined voltage.

As described above, in the state before charging the first smoothing capacitor, the voltage at the previous start remains on the motor side from the boosting means, and the voltage value detected by the motor side voltage detecting means is detected by the power supply voltage detecting means. When the voltage value is larger than the value that is lower than the predetermined voltage by a predetermined voltage, it is determined that charging is not normally completed even if the first smoothing capacitor is charged. Therefore, in this case, even if charging of the first smoothing capacitor is started, useless charging is performed.
Therefore, according to the present invention, the electric vehicle is provided with charging start determining means for determining the start timing of charging by the capacitor charging means, and the voltage value detected by the motor side voltage detecting means is the voltage value detected by the power supply voltage detecting means. The time when the voltage became lower than the predetermined voltage by the capacitor charging means was set as the charging start timing by the capacitor charging means. For this reason, useless charge can be prevented by starting charge of the 1st smoothing capacitor, after determining that it is the start time of charge by the charge start judging means.

  In this case, capacitor voltage detection means (for example, a voltmeter 61 described later) for detecting the voltage of the first smoothing capacitor, and failure determination means for determining whether or not the capacitor voltage detection means is operating normally. And the charging completion determining means, when the failure determining means determines that the capacitor voltage detecting means is operating normally, the voltage value of the power supply voltage detecting means and the voltage value of the capacitor voltage detecting means If the difference between the two is within a predetermined range, it is preferable to determine that the operation has been completed normally.

As described above, when the voltage of the first smoothing capacitor of the boosting unit changes, the voltage on the motor side of the boosting unit changes accordingly. Therefore, instead of the voltage of the first smoothing capacitor, the motor side of the boosting unit It can be determined whether or not the charging of the first smoothing capacitor has been normally completed. However, since the voltage at the time of the previous start remains on the motor side from the boosting means, the voltage value on the motor side from the boosting means may be different from the voltage value of the first smoothing capacitor, and the charging of the first smoothing capacitor may occur. There is a risk that the accuracy of determining whether or not has been completed normally will be slightly reduced.
Therefore, according to the present invention, the electric vehicle is provided with capacitor voltage detection means for detecting the voltage of the first smoothing capacitor, and failure determination means for determining whether or not the capacitor voltage detection means is operating normally. Provided. Then, when it is determined by the failure determination means that the capacitor voltage detection means is operating normally, the difference between the voltage value detected by the capacitor voltage detection means and the voltage value detected by the power supply voltage detection means is a predetermined value. If it was within the range, it was determined that charging of the first smoothing capacitor was completed normally. Therefore, when the capacitor voltage detecting means operates normally, whether or not the charging of the first smoothing capacitor is normally completed using the voltage of the first smoothing capacitor rather than the voltage on the motor side from the boosting means. Can be determined with high accuracy.

  On the other hand, when the capacitor voltage detection means does not operate normally and the failure determination means determines that the capacitor voltage detection means does not operate normally, as described above, the voltage on the motor side and the power supply Based on the voltage, it is determined whether or not charging of the first smoothing capacitor has been completed normally. Therefore, even when the capacitor voltage detection means fails, it can be determined whether or not the charging of the first smoothing capacitor has been completed normally.

  In this case, it is preferable that the motor side voltage detecting means detects a voltage of electric power supplied to the inverter.

  Conventionally, an electric vehicle is provided with a voltmeter that detects a voltage of electric power supplied to an inverter. Therefore, according to the present invention, since the voltmeter provided in the above-described conventional electric vehicle is used as the motor side voltage detecting means, the voltage on the motor side can be detected by the boosting means without providing a new configuration.

  In this case, it is preferable that the motor side voltage detecting means detects the voltage boosted by the boosting means.

  Conventionally, an electric vehicle is provided with a voltmeter that detects a voltage boosted by a boosting means. Therefore, according to the present invention, since the voltmeter provided in the above-described conventional electric vehicle is used as the motor side voltage detecting means, the voltage on the motor side can be detected by the boosting means without providing a new configuration.

  According to the present invention, in the electric vehicle, the motor side voltage detecting means for detecting the motor side voltage from the boosting means, the voltage value detected by the motor side voltage detecting means and the voltage value detected by the power supply voltage detecting means. Charging completion determining means for determining whether or not the charging of the first smoothing capacitor has been normally completed on the basis thereof. When the voltage of the first smoothing capacitor changes, the voltage on the motor side from the boosting means changes accordingly. Therefore, the first smoothing capacitor can be charged without using the means for detecting the voltage of the first smoothing capacitor. It can be determined whether or not is completed normally.

In addition, the following two conditions were provided as conditions for determining by the charging completion determining means that the charging of the first smoothing capacitor was normally completed. The first condition is that the voltage value detected by the motor-side voltage detection means is equal to or lower than a value lower by a predetermined voltage than the voltage value detected by the power supply voltage detection means in a state before charging the first smoothing capacitor. . The second condition is that the difference between the voltage value detected by the motor side voltage detection means and the voltage value detected by the power supply voltage detection means is within a predetermined range in the state after the first smoothing capacitor is charged. It is.
Therefore, in the state before charging the first smoothing capacitor, the voltage at the time of the previous start remains on the motor side from the boosting means, and the voltage value detected by the motor side voltage detecting means is the voltage value detected by the power supply voltage detecting means. If the value is larger than the value lower than the predetermined voltage, the first condition described above is not satisfied. Therefore, in the state before charging the first smoothing capacitor, even if the voltage at the time of the previous start remains on the motor side from the boosting means, it is mistakenly assumed that the charging of the first smoothing capacitor has been completed normally. Discrimination can be prevented.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same constituent elements are denoted by the same reference numerals, and the description thereof is omitted or simplified.
[First Embodiment]
FIG. 1 is a block diagram of a drive system 1 provided in the electric vehicle according to the first embodiment of the present invention.
The drive system 1 includes a control device 5 as charging completion determination means, a battery 30 as power supply, a DC / DC converter 50 as boosting means, an inverter 70 constituting a power drive unit, and a motor 90.

The battery 30 outputs DC power. This battery 30 is connected to an inverter 70 via a DC / DC converter 50, and the inverter 70 is connected to a motor 90.
The battery 30 and the DC / DC converter 50 are intermittently connected by the relay circuit 40.
Between the positive terminal P3 and the negative terminal P4 of the battery 30, a voltmeter 45 is connected as a power supply voltage detecting means for detecting the voltage of the battery 30 (hereinafter referred to as VBAT).

The inverter 70 drives the motor 90 by converting DC power supplied from the battery 30 through the DC / DC converter 50 into AC power and supplying the AC power to the motor 90. A positive terminal P9 of the inverter 70 is connected to a positive terminal P7 of the DC / DC converter 50, and a negative terminal P10 of the inverter 70 is connected to a negative terminal P8 of the DC / DC converter 50.
Between the positive terminal P9 and the negative terminal P10 of the inverter 70, a smoothing capacitor 81 as a second smoothing capacitor for smoothing the waveform of the voltage, and a voltage on the motor 90 side from the DC / DC converter 50 are smoothed. A voltmeter 82 as motor side voltage detecting means for detecting the voltage of the capacitor 81 (hereinafter referred to as VPIN), a discharge resistor 83 for reducing the voltage remaining in the DC / DC converter 50, the inverter 70, the smoothing capacitor 81, etc. , Is connected.

The DC / DC converter 50 boosts and outputs a DC voltage. The positive terminal P5 of the DC / DC converter 50 is connected to the positive terminal P3 of the battery 30 via the relay circuit 40, and the negative terminal P6 of the DC / DC converter 50 is connected to the battery 30 via the relay circuit 40. To the negative electrode side terminal P4.
The DC / DC converter 50 includes a smoothing capacitor that smoothes a voltage waveform.
Between the positive terminal P5 and the negative terminal P6 of the DC / DC converter 50, the above-described smoothing capacitor and a voltmeter 61 for detecting the voltage of the smoothing capacitor (hereinafter referred to as V1) are connected. ing. Further, a voltmeter 62 for detecting a voltage (hereinafter referred to as V2) output from the DC / DC converter 50 is connected between the positive terminal P7 and the negative terminal P8.

  The relay circuit 40 includes a positive side main contactor 41 and a precharge contactor 43 that connect the positive side terminal P3 of the battery 30 to a positive side terminal P5 of the DC / DC converter 50, and a negative side terminal P4 of the battery 30 as a DC / DC converter. A negative-side main contactor 42 intermittently connected to 50 negative-side terminals P6; and a resistor 44 connected in series to the precharge contactor 43. The precharge contactor 43 and the resistor 44 connected in series are connected in parallel to the positive-side main contactor 41.

  The control device 5 controls the positive-side main contactor 41, the negative-side main contactor 42, the precharge contactor 43, and the DC / DC converter 50, and whether or not precharge of the first smoothing capacitor 58 described later has been normally completed. Is determined.

FIG. 2 is a circuit diagram of the DC / DC converter 50.
The DC / DC converter 50 includes a first transistor 51, a second transistor 52, a first diode 53, a second diode 54, a reactor 55, a first resistor 56, a second resistor 57, and a first smoothing capacitor as a first smoothing capacitor. A capacitor 58 and a second smoothing capacitor 59 are provided.
The DC / DC converter 50 is provided with positive terminals P5 and P7 and negative terminals P6 and P8.

One end side of the reactor 55 is connected to the positive terminal P5.
The first transistor 51 and the second transistor 52 are composed of, for example, an IGBT (Insulated Gate Bipolar Mode Transistor). The collector of the first transistor 51 is connected to the other end of the reactor 55, the emitter is connected to the negative terminals P6 and P8, and the gate is connected to a control circuit (not shown). The collector of the second transistor 52 is connected to the positive terminal P7, the emitter is connected to the other end of the reactor 55, and the gate is connected to a control circuit (not shown).

  A first diode 53 is connected between the emitter and the collector of the first transistor 51 in the forward direction from the emitter to the collector, and between the emitter and the collector of the second transistor 52 in the forward direction from the emitter to the collector. A second diode 54 is connected in the direction.

One end of the first resistor 56 and the first smoothing capacitor 58 is connected to the positive terminal P5, and the other end is connected to the negative terminal P6.
One end of the second resistor 57 and the second smoothing capacitor 59 is connected to the positive terminal P7, and the other end is connected to the negative terminal P8.

The DC / DC converter 50 operates as follows.
That is, first, when the first transistor 51 and the second transistor 52 are turned off and DC power is supplied to the positive terminal P5, a voltage corresponding to the DC power is applied to the first smoothing capacitor 58, and the first smoothing capacitor 58 58 precharge is started.

  Next, when the first transistor 51 is turned on after the precharging of the first smoothing capacitor 58 is completed, a current flows from the positive terminal P5 to the negative terminal P6 via the reactor 55 and the first transistor 51. This current excites the reactor 55 and accumulates magnetic energy.

  Next, when the first transistor 51 is turned off, a counter electromotive force is generated in the reactor 55 by the accumulated magnetic energy. This counter electromotive force is superimposed on the voltage of the first smoothing capacitor 58 and output from the positive terminal P7.

  Note that, during the period in which the first smoothing capacitor 58 is precharged, the first transistor 51 and the second transistor 52 are in an off state, so that the DC / DC converter 50 is stopped, but the reactor 55 and the second diode 54 are switched off. Thus, current flows from the battery 30 toward the inverter 70. For this reason, during the period in which the first smoothing capacitor 58 is precharged, the smoothing capacitor 81 is also precharged.

  The on / off control of the first transistor 51 and the second transistor 52 is performed by the control device 5 in accordance with the power value required from the motor 90. Specifically, the switching cycle of the first transistor 51 and the second transistor 52 is controlled according to the voltage V2.

  The procedure for performing precharging in the above drive system 1 will be described with reference to the flowchart of FIG.

  First, in step ST1, the value of the voltage VPIN of the smoothing capacitor 81 before the start of precharge is stored as VPIN2 in a storage area provided in the control device 5.

Next, in step ST2, precharging is started. Specifically, the control device 5 turns off the positive-side main contactor 41 and turns on the precharge contactor 43 and the negative-side main contactor 42. Then, the DC power output from the battery 30 is supplied to the DC / DC converter 50 through the precharge contactor 43 and the negative main contactor 42 in the on state, and charging of the first smoothing capacitor 58 is started.
In step ST2, the precharge is started, and at the same time, the timer of the control device 5 starts measuring the precharge time.

  Next, in step ST3, it is determined whether or not a predetermined time has elapsed since the start of precharging. Specifically, it is determined whether or not the time counted by the timer of the control device 5 has reached a predetermined time T. If this determination is YES, the process moves to step ST4, and if NO, step ST3 is repeated.

  In step ST4, the control device 5 determines whether or not the difference between the voltage VBAT of the battery 30 and the voltage VPIN of the smoothing capacitor 81 is within a predetermined range. Specifically, it is determined whether or not the difference between the voltage VBAT of the battery 30 and the voltage VPIN of the smoothing capacitor 81 is a predetermined value A or less. If this determination is YES, the process moves to step ST5, and if NO, the process moves to step ST8.

In step ST5, the control device 5 determines whether or not the voltage VPIN of the smoothing capacitor 81 before the start of precharging is equal to or lower than a value lower than the voltage VBAT of the battery 30 by a predetermined voltage. Specifically, it is determined whether or not a value obtained by subtracting voltage VPIN2 from voltage VBAT of battery 30 is equal to or greater than a predetermined value B. If this determination is YES, the process moves to step ST6, and if NO, the process moves to step ST8.
The predetermined value B is set so that the voltage at the previous activation remaining in the smoothing capacitor 81 is reduced to some extent, and the first smoothing capacitor 58 is normally precharged. For example, in the present embodiment, when the predetermined value B is set to 0 and the voltage VPIN of the smoothing capacitor 81 before the start of precharge is equal to or lower than the voltage VBAT of the battery 30, the process proceeds to step ST6 and is higher. Therefore, the process proceeds to step ST8.

  In step ST6, the control device 5 determines that the precharge has been normally completed, and the positive side main contactor 41 is turned on. In step ST7, the precharge contactor 43 is turned off.

  In step ST8, the control device 5 determines that the precharge is not normally completed, and in step ST9, the precharge contactor 43 and the negative-side main contactor 42 are turned off.

FIG. 4 is a timing chart of precharging when the first smoothing capacitor 58 operates normally.
Here, the positive side main contactor 41, the negative side main contactor 42, and the precharge contactor 43 are turned off at the L level and turned on at the H level.
The voltage VBAT of the battery 30 is VC3 at time t0, and the voltage VPIN of the smoothing capacitor 81 is VC1 lower than VC3 at time t0. That is, at time t0, voltage VPIN of smoothing capacitor 81 is assumed to be lower than voltage VBAT of battery 30.

  At time t1, the precharge contactor 43 is turned on, and at the time t2, the negative-side main contactor 42 is turned on. Then, the DC power output from the battery 30 is supplied to the DC / DC converter 50 through the precharge contactor 43 and the negative main contactor 42 in the on state, and charging of the first smoothing capacitor 58 is started.

  Here, one end side of the first smoothing capacitor 58 is connected to one end side of the smoothing capacitor 81 via the reactor 55 and the second diode 54, and the other end side of the first smoothing capacitor 58 is the other end of the smoothing capacitor 81. Connected to the side. For this reason, when the voltage V1 of the first smoothing capacitor 58 changes, the voltage VPIN of the smoothing capacitor 81 also changes accordingly. As a result, at time t3 after the elapse of the predetermined time T from time t2, the voltage VPIN of the smoothing capacitor 81 rises to VC3. That is, at time t <b> 3, voltage VPIN of smoothing capacitor 81 becomes equal to voltage VBAT of battery 30.

  At time t3, it is determined that precharge is completed based on VPIN and VBAT at time t0 and time t3. Then, the positive-side main contactor 41 is turned on, and the precharge contactor 43 is turned off at time t4. Then, the DC power output from the battery 30 is supplied to the DC / DC converter 50 via the positive-side main contactor 41 and the negative-side main contactor 42 in the on state. For this reason, since the voltage V1 of the first smoothing capacitor 58 is maintained, the voltage VPIN of the smoothing capacitor 81 is also maintained at VC3.

FIG. 5 is a timing chart of precharging when a failure occurs in the first smoothing capacitor 58.
Here, the voltage VBAT of the battery 30 is VC3 at time t10, and the voltage VPIN of the smoothing capacitor 81 is VC1 at time t10. That is, at time t <b> 10, voltage VPIN of smoothing capacitor 81 is assumed to be lower than voltage VBAT of battery 30.

  At time t11, the precharge contactor 43 is turned on, and at time t12, the negative-side main contactor 42 is turned on. Then, the DC power output from the battery 30 is supplied to the DC / DC converter 50 through the precharge contactor 43 and the negative main contactor 42 in the on state. However, since the first smoothing capacitor 58 cannot be charged due to the malfunction of the first smoothing capacitor 58, the voltage VPIN of the smoothing capacitor 81 is higher than the voltage VBAT of the battery 30 at time t13 after the elapse of the predetermined time T from time t12. It rises only to a low VC2. That is, at time t <b> 13, voltage VPIN of smoothing capacitor 81 is different from voltage VBAT of battery 30.

  At time t13, based on VPIN and VBAT at time t10 and time t13, it is determined that precharge is not completed. At time t14, the precharge contactor 43 and the negative main contactor 42 are turned off. Then, since the DC power output from the battery 30 is not supplied to the DC / DC converter 50, the voltage V1 of the first smoothing capacitor 58 gradually decreases, and the voltage VPIN of the smoothing capacitor 81 gradually decreases accordingly. To do.

FIG. 6 is a timing chart of precharging when the voltage at the previous activation remains in the smoothing capacitor 81.
Here, the voltage VBAT of the battery 30 is VC3 at time t20, and the voltage VPIN of the smoothing capacitor 81 is VC4 higher than VC3 at time t20. That is, at time t20, voltage VPIN of smoothing capacitor 81 is higher than voltage VBAT of battery 30.

  At time t21, the precharge contactor 43 is turned on, and at time t22, the negative main contactor 42 is turned on. Then, the DC power output from the battery 30 is supplied to the DC / DC converter 50 through the precharge contactor 43 and the negative main contactor 42 in the on state. However, the voltage remaining in the smoothing capacitor 81 is consumed by the discharge resistor 83 connected in parallel with the smoothing capacitor 81. For this reason, the voltage VPIN of the smoothing capacitor 81 gradually decreases, and at time t23 after a predetermined time T has elapsed from time t22, the voltage VPIN of the smoothing capacitor 81 decreases to VC3. That is, at time t23, voltage VPIN of smoothing capacitor 81 becomes equal to voltage VBAT of battery 30.

  At time t23, based on VPIN and VBAT at time t20 and time t23, it is determined that precharge is not completed. Then, the positive-side main contactor 41 is turned off, and the precharge contactor 43 is turned off at time t24. Then, the DC power output from the battery 30 is not supplied to the DC / DC converter 50, so that the voltage VPIN of the smoothing capacitor 81 gradually decreases as from time t20 to time t24.

According to this embodiment, there are the following effects.
(1) The precharge of the first smoothing capacitor 58 is normally completed based on the voltmeter 82 for detecting the voltage of the smoothing capacitor 81 and the voltage value detected by the voltmeter 82 and the voltage value detected by the voltmeter 45. And a control device 5 for determining whether or not the operation has been performed. When the voltage of the first smoothing capacitor 58 is changed, the voltage of the smoothing capacitor 81 is changed accordingly. Therefore, the voltage of the first smoothing capacitor 58 is detected without using the voltmeter 61 for detecting the voltage of the first smoothing capacitor 58. It can be determined whether or not the charging has been completed normally.

(2) The following two conditions are provided as conditions for the control device 5 to determine that precharge of the first smoothing capacitor 58 has been completed normally. The first condition is that the voltage value detected by the voltmeter 82 is lower than the voltage value detected by the voltmeter 45 by a predetermined voltage or less before the first smoothing capacitor 58 is precharged. The second condition is that the difference between the voltage value detected by the voltmeter 82 and the voltage value detected by the voltmeter 45 is within a predetermined range in a state after the first smoothing capacitor 58 is precharged. .
Therefore, in the state before the precharge of the first smoothing capacitor 58, the voltage at the time of the previous start remains from the DC / DC converter 50 to the motor 90 side, and the voltage value detected by the voltmeter 82 is detected by the voltmeter 45. When the voltage value is larger than the value lower by a predetermined voltage, the first condition described above is not satisfied. Therefore, in the state before the precharge of the first smoothing capacitor 58, the precharge of the first smoothing capacitor 58 is normal even when the voltage at the time of the previous activation remains from the DC / DC converter 50 to the motor 90 side. It is possible to prevent erroneous determination of completion.

[Second Embodiment]
FIG. 7 is a flowchart for determining the precharge start timing according to the second embodiment of the present invention.

  First, when the ignition switch (IG) is turned on, it is determined whether or not the voltage VPIN of the smoothing capacitor 81 is equal to or higher than a value lower than the voltage of the battery 30 by a control device 5A serving as a charging start determination unit. . Specifically, it is determined whether or not a value obtained by subtracting voltage VPIN2 from voltage VBAT of battery 30 is equal to or greater than a predetermined value B. If this determination is YES, precharge is started, and if NO, step ST11 is repeated.

According to this embodiment, in addition to the above (1) and (2), there are the following effects.
(3) The control device 5A for determining the start timing of the precharge by the battery 30 is provided, and after the voltage value detected by the voltmeter 82 becomes equal to or higher than a value lower than the voltage value detected by the voltmeter 45 by a predetermined voltage, The start time of the precharge by the battery 30 was set. For this reason, useless precharge can be prevented by starting precharge of the first smoothing capacitor 58 after the control device 5A determines that the precharge start time is reached.

[Third Embodiment]
FIG. 8 is a block diagram of a drive system 1B included in an electric vehicle according to the third embodiment of the present invention.
In the present embodiment, the drive system 1 </ b> B includes a fuel cell 10 that generates power by chemically reacting a reaction gas, and a reaction gas supply device 23 that supplies the reaction gas to the fuel cell 10. Different.

The fuel cell 10 is connected to a reaction gas supply device 23, and generates DC power by an electrochemical reaction when supplied with hydrogen gas and air. The fuel cell 10 is connected to an inverter 70 in parallel with the DC / DC converter 50 and the battery 30.
The fuel cell 10 and the inverter 70 are intermittently connected by the first relay circuit 20.

  The inverter 70 drives the motor 90 by converting the DC power supplied from the battery 30 via the fuel cell 10 or the DC / DC converter 50 into AC power and supplying the AC power to the motor 90. The positive terminal P9 of the inverter 70 is connected to the positive terminal P1 of the fuel cell 10 via the first relay circuit 20 in addition to the positive terminal P7 of the DC / DC converter 50, and the negative terminal of the inverter 70. P10 is connected to the negative terminal P2 of the fuel cell 10 via the first relay circuit 20 in addition to the negative terminal P8 of the DC / DC converter 50.

  The first relay circuit 20 intermittently connects the positive terminal P1 of the fuel cell 10 to the positive terminal P9 of the inverter 70, and the negative terminal P2 of the fuel cell 10 to the negative terminal P10 of the inverter 70. Negative electrode side contactor 22.

The above drive system 1A operates as follows.
That is, first, with the positive-side main contactor 41 of the second relay circuit 40 turned off, the precharge contactor 43 is turned on and the negative-side main contactor 42 is turned on to charge the first smoothing capacitor 58 (hereinafter referred to as “the first smoothing capacitor 58”). Called primary precharge).

This primary precharge is performed until it is determined that the precharge of the first smoothing capacitor 58 has been normally completed based on the voltage VPIN of the smoothing capacitor 81 and the voltage VBAT of the battery 30. Specifically, in this embodiment, the process is performed until the voltage VPIN becomes equal to the voltage VBAT.
Thereafter, the precharge contactor 43 is turned off and the positive-side main contactor 41 is turned on to charge the smoothing capacitor 81 (hereinafter referred to as secondary precharge).

The secondary precharge is performed until it is determined that the precharge of the smoothing capacitor 81 is normally completed based on the voltage VPIN of the smoothing capacitor 81 and the voltage VBAT of the battery 30. Specifically, in this embodiment, the process is performed until the voltage VPIN becomes equal to the voltage of the fuel cell 10.
Thereafter, the positive side main contactor 41 and the negative side main contactor 42 of the second relay circuit 40 are turned off, and the positive side contactor 21 and the negative side contactor 22 of the first relay circuit 20 are turned on. DC power is supplied to the inverter 70 and converted into AC power by the inverter 70 to drive the motor 90.

According to this embodiment, there are the following effects.
(4) Based on the voltage VPIN detected by the voltmeter 82 and the voltage VBAT detected by the voltmeter 45, the control device 5B for determining whether or not the primary precharge of the first smoothing capacitor 58 has been normally completed. Provided. When the voltage of the first smoothing capacitor 58 changes, the voltage of the smoothing capacitor 81 changes accordingly. Therefore, the primary precharge is normally performed without using the voltmeter 61 that detects the voltage of the first smoothing capacitor 58. It can be determined whether or not it has been completed.

(5) The following two conditions are provided as conditions for the control device 5 to determine that precharge of the first smoothing capacitor 58 has been completed normally. The first condition is that the voltage value detected by the voltmeter 82 is lower than the voltage value detected by the voltmeter 45 by a predetermined voltage or less before the first smoothing capacitor 58 is precharged. The second condition is that the difference between the voltage value detected by the voltmeter 82 and the voltage value detected by the voltmeter 45 is within a predetermined range in a state after the first smoothing capacitor 58 is precharged. .
Therefore, in the state before the precharge of the first smoothing capacitor 58, the voltage at the time of the previous start remains from the DC / DC converter 50 to the motor 90 side, and the voltage value detected by the voltmeter 82 is detected by the voltmeter 45. When the voltage value is larger than the value lower by a predetermined voltage, the first condition described above is not satisfied. Therefore, in the state before the precharge of the first smoothing capacitor 58, the primary precharge is normally completed even if the voltage at the time of the previous start-up remains on the motor 90 side from the DC / DC converter 50. It is possible to prevent erroneous determination.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements and the like within a scope that can achieve the object of the present invention are included in the present invention.

  Further, in each of the above-described embodiments, the voltage VPIN of the smoothing capacitor 81 is used as the voltage on the motor 90 side from the DC / DC converter 50. However, the voltage V2 output from the DC / DC converter 50 is not limited to this. May be used.

  In each of the above-described embodiments, the voltage VPIN of the smoothing capacitor 81 before the start of precharging is used when performing precharging. However, the present invention is not limited to this. For example, the voltage VPIN of the smoothing capacitor 81 may be detected at the end of operation of the electric vehicle, and this detected value may be used when precharging at the next startup.

  For example, in the above-described third embodiment, the smoothing capacitor 81 of the inverter 70 is precharged by the battery 30 and it is determined that the precharging is almost completed, and then the fuel cell 10 is connected to the inverter 70. The configuration may be such that the smoothing capacitor 81 of the inverter 70 is precharged by the fuel cell 10 and the battery 30 is connected to the inverter 70 after it is determined that the precharge is almost completed.

  The drive systems 1, 1 </ b> A, and 1 </ b> B according to the above-described embodiments can be applied to EVs (Electric Vehicles) and HEVs (Hybrid Electric Vehicles).

It is a block diagram of the drive system with which the electric vehicle which concerns on 1st Embodiment of this invention is provided. 2 is a circuit diagram of a DC / DC converter included in the drive system. FIG. It is a figure for demonstrating the procedure which performs a precharge in the said drive system. 6 is a timing chart of precharge when the first smoothing capacitor operates normally. It is a timing chart of precharge when a malfunction occurs in the first smoothing capacitor. It is a timing chart of precharge when the voltage at the time of previous activation remains in the smoothing capacitor. It is a flowchart which judges the start time of the precharge which concerns on 2nd Embodiment of this invention. It is a block diagram of the drive system with which the electric vehicle which concerns on 3rd Embodiment of this invention is provided.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1B, 100 ... Drive system 5, 5A, 5B ... Control apparatus 10 ... Fuel cell 30 ... Battery 41 ... Positive side main contactor 42 ... Negative side main contactor 43 ... Precharge contactor 45, 61, 82 ... Voltmeter 58 ... First smoothing capacitor 70 ... Inverter 81 ... Smoothing capacitor

Claims (6)

A motor for driving the vehicle;
A power supply that outputs DC power;
Boosting means configured to include a first smoothing capacitor and boost the voltage of the DC power output from the power supply;
An inverter that includes a second smoothing capacitor, converts the DC power boosted by the boosting means to AC power, and supplies the AC power to the motor;
A main contactor for intermittently connecting the power source and the booster;
A precharge circuit that is connected in parallel with the main contactor and intermittently connects the power source and the booster;
Power supply voltage detecting means for detecting the voltage of the power supply;
Motor side voltage detecting means for detecting the motor side voltage from the boosting means;
At the time of starting the vehicle, the main contactor is turned off and the precharge circuit is turned on to connect the power source and the boosting means, so that the first smoothing capacitor and the second smoothing capacitor are connected. Capacitor charging means for charging the capacitor;
Capacitor discharging means for discharging the electric power stored in the first smoothing capacitor and the second smoothing capacitor when the vehicle is stopped;
A charging completion determination means the charge it is determined whether or not successful,
An electric vehicle comprising: circuit switching means for turning off the precharge circuit and turning on the main contactor when the charging completion judging means determines that the charging has been normally completed. There,
The boosting means includes a switching element connected to the motor side from the first smoothing capacitor, a diode connected in parallel to the switching element, and allowing a current to flow from the power supply side to the motor side. With
It said charging completion determination means,
When the voltage value of the motor side voltage detection means before charging is equal to or lower than a voltage value lower than the voltage value of the power supply voltage detection means by a predetermined voltage , the voltage at the previous start of the vehicle remaining on the motor side from the boosting means is Judging that the charging has been sufficiently reduced, determining that the charging has been completed normally ,
If the voltage value of the motor-side voltage detection means before charging is not less than a value lower than the voltage value of the power supply voltage detection means by a predetermined voltage or less, the voltage at the previous start of the vehicle remains on the motor side from the boosting means. And determining that the charging has not been completed normally . The electric vehicle according to claim 1,
Charging start determining means for determining the start timing of charging by the capacitor charging means,
The charging start determining means sets the charging start timing by the capacitor charging means after the voltage value of the motor side voltage detecting means becomes equal to or higher than a voltage value lower than the voltage value of the power supply voltage detecting means by a predetermined voltage. Electric car characterized by.   The electric vehicle according to claim 1 or 2,
  A fuel cell connected in parallel to the power source and connected to the inverter, generating a chemical reaction with a reaction gas and generating DC power; and
  An electric vehicle, further comprising: a fuel cell side contactor for intermittently connecting the fuel cell and the inverter.   The electric vehicle according to claim 3,
  When the vehicle is started, the main contactor and the fuel cell side contactor are turned off, and the precharge circuit is turned on to connect the power source and the boosting means, whereby the motor side voltage detecting means Until the voltage value of the power supply voltage detecting means becomes equal to the voltage value of the power supply voltage detecting means, the primary precharge for charging the first smoothing capacitor and the second smoothing capacitor is performed,
  When the primary precharge is completed, the circuit switching means turns off the precharge circuit and turns on the main contactor, thereby connecting the power supply and the boosting means, Performing secondary precharge to charge the second smoothing capacitor until the voltage value of the voltage detection means becomes equal to the voltage value of the fuel cell;
  When the secondary precharge is completed, the fuel cell side contactor is turned on. The electric vehicle according to any one of claims 1 to 4 ,
The electric vehicle according to claim 1, wherein the motor side voltage detecting means detects a voltage of electric power supplied to the inverter. The electric vehicle according to any one of claims 1 to 4 ,
The electric vehicle according to claim 1, wherein the motor side voltage detecting means detects a voltage boosted by the boosting means.

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