JPH09284912A - Fault detector for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an erroneous detection that a voltage drop of a main battery is erroneously detected as an open mode fault of a contactor, etc. SOLUTION: Whether there is an open mode fault in a contactor B, etc., which opens and closes the connection between a generator 16 and a main battery 26 is detected by detecting the voltage Vj by a voltage sensor located at the generator 16 side in view of the contactor B and comparing the value of the voltage Vj with a threshold. When the current Ii detected by a current sensor 44 exceeds a specified threshold for detection even if the open mode fault judgement condition that the voltage Vj shows the value equal to a specified threshed or less satisfied, it is inhibited that a fault is judged as an open mode fault, or the threshold for detecting fault is changed to a lower one.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure detection device for detecting an open mode failure of a contactor or the like in a hybrid vehicle.

[0002]

2. Description of the Related Art A main battery and a vehicle drive system that receives electric power from the main battery (also referred to as a drive system in the present application)
Vehicles equipped with are called electric vehicles, and vehicles equipped with an additional electric power source or power source are called hybrid vehicles. Among hybrid vehicles, those equipped with a power source capable of supplying electric power to a main battery and a drive system are called series hybrid vehicles (SHV). In SHV vehicles, a contactor is usually provided between the main battery and the power source to open and close the connection between the two. By turning on this contactor and then starting the operation of the electric power source, electric power can be supplied from the electric power source to the main battery. As a result, the main battery whose state of charge (SOC) has deteriorated can be charged by the power supply to the drive system, and therefore the SOC of the main battery can be restored. In addition, since the former can be covered by the latter by controlling the output of the power source according to the power to be supplied to the drive system, the frequency of charging / discharging the main battery can be suppressed,
As a result, the life of the main battery can be extended.

[0003]

Here, in the above-mentioned contactor and a component such as a fuse which is connected in series between the main battery and the power source similarly to the above-mentioned contactor, a failure in an open mode (in this application, the fuse is blown, etc. Strictly speaking, “things that cannot be said to be“ faults ”) occur, power cannot be supplied from the power source to the main battery. In order to detect such a situation, for example, the state of the contactor may be detected by a micro switch. That is, when the micro switch does not detect the command to turn on the contactor, it can be considered that the open mode failure has occurred in the contactor or the like. However, this method has a problem in that a micro switch must be provided and thus the device configuration becomes complicated.

As a method of detecting an open mode failure without a microswitch, the voltage applied from the main battery to the power source at a time point after the power source is operated after the contactor is instructed to turn it on. There is a method of detecting at a position closer to the power source as viewed from the contactor. That is, the voltage at this position before the operation of the power source is a relatively high voltage determined by the terminal voltage of the main battery if the contactor or the like is normal, whereas if the contactor or the like has an open mode failure. , The voltage determined by the output of the power source, that is, 0. Therefore, by using this voltage for the threshold judgment, the open mode failure of the contactor or the like can be detected without the micro switch. See also Japanese Utility Model Laid-Open No. 62-114860 concerning the detection of voltage abnormality of the power source.

However, the failure detection method by voltage detection has a problem that it may be erroneously detected that an open mode failure has not occurred in the contactor or the like. For example, when the vehicle operator requests rapid acceleration, the voltage of the main battery generally decreases as a large current is supplied from the main battery to the drive system. This voltage drop becomes significant when the SOC of the main battery is low. When the voltage detection and the failure detection according to the above-described procedure are executed during the low SOC sudden acceleration in which the voltage drop occurs in this way, the voltage drop due to the low SOC sudden acceleration etc. is erroneously caused and the voltage non-application due to the open mode failure is caused. It will be detected as a state. Such erroneous detection impairs the advantage of the SHV that the main battery can be charged and the power supply to the drive system can be executed by the power source output even at low SOC. In addition, especially in a system that prohibits the operation of the power source in response to the detection of an open mode failure, once the operation of the power source is prohibited, even if it is caused by the above-mentioned erroneous detection, the prohibited state In order to cancel the above, the vehicle operator has to perform the ignition off operation and the on operation again.

One of the objects of the present invention is to prevent the false detection of the open mode detection condition due to the low SOC of the main battery and the large current of the drive system by improving the open mode failure detection condition. This makes it possible to maintain the advantages of the SHV and not to impose an operation burden on the vehicle operator. One of the objects of the present invention is to make it possible to distinguish an open mode failure of a contactor or the like and a voltage drop due to low SOC sudden acceleration or the like. One of the objects of the present invention is to realize each of the above objects without special addition of a device.

[0007]

In order to achieve such an object, a first structure of the present invention is a main battery for supplying electric power to a drive system (for example, a motor) and a power for supplying electric power to the main battery. In a failure detection device used in a hybrid vehicle in which a contactor for opening / closing the connection between a power source (for example, a generator) is provided, a main battery and a power source should be connected to the contactor. Before the start of the operation of the power source after the command signal is given, the means for detecting the voltage applied to the power source from the main battery and the current supplied to the drive system from the main battery, and the above-mentioned voltage threshold for failure determination. Since it is less than or equal to the value, means for detecting the occurrence of an open mode failure in the contactor or a component connected in series with the contactor, and if the current exceeds the detection execution threshold value In, characterized in that it comprises a means for inhibiting the detection of the open mode failure, the.

In this configuration, when the main battery supplies a relatively large current exceeding the detection execution threshold value to the drive system, the voltage determination process related to the detection of the open mode failure is prohibited. Therefore, even when the voltage of the main battery is reduced due to the large current discharge at the time of low SOC, there is no possibility of erroneously detecting the voltage reduction as an open mode failure of the contactor or the like. As a result, the advantages inherent to hybrid vehicles, such as being able to supply electric power to the drive system instead of the main battery at low SOC and charging the main battery, are not impaired even in such a situation, and the vehicle operator can perform an ignition operation or the like. Does not have to bear the burden of. Furthermore, since this configuration can be realized almost by changing the control logic, it is almost unnecessary to add a device.

The second configuration of the present invention replaces the open mode failure detection inhibiting means in the first configuration with a smaller value when the current is above the detection execution threshold than when it is below the detection execution threshold. Therefore, a means for changing the failure determination threshold value is provided. In the present configuration, when the main battery supplies a relatively large current exceeding the detection execution threshold value to the drive system, the failure determination threshold value is reduced and corrected. Therefore, the same operation as the first configuration occurs. In addition to this, open mode failure detection is performed using the failure determination threshold value after reduction correction. Therefore, depending on the setting of the failure determination threshold value after reduction correction, large current discharge at low SOC, etc. It becomes possible to distinguish the voltage drop of the main battery due to the above from the open mode failure of the contactor or the like.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. It should be noted that the same or corresponding members or processes between the respective embodiments are designated by the same reference numerals, and redundant description will be omitted.

(1) System Configuration FIG. 1 shows the configuration of SHV suitable for implementing the present invention. The SHV drive system 10 includes a three-phase AC motor 12 connected to wheels via a mechanism (not shown), and an inverter 14 that converts drive power from DC to three-phase AC and supplies the motor 12. The power generator (power source) 16 includes an engine 18, a three-phase AC generator 20 that is rotationally driven by the engine 18, and an inverter (or rectifier) 22 that converts the output of the generator 20 from three-phase AC to DC.
It is composed of Further, the DC side terminals of the inverters 14 and 22 are connected to the main battery 26 via the junction box 24. Therefore, when all the contactors in the junction box 24 are on, and when the contactor and its peripheral parts are all operating normally, the power output of the generator 20 and the discharge output of the main battery 26 are output. Thus, the motor 12 can be driven to propel the vehicle, and the main battery 26 can be charged with the power generation output of the generator 20 and the regenerative output of the motor 12.

Further, a motor ECU (electronic control unit)
28 controls the power conversion operation by the inverter 14 to control the output of the motor 12 so as to obtain an output according to the operation of the accelerator or the brake. On the other hand, battery EC
The U30 detects the current I _B and the voltage V _B of the main battery 26 by using the current sensor 32 and the voltage sensor 34, and detects the detected current I _B and the voltage V _B and the SOC obtained from the result.
Is notified to the motor ECU 28 and the power generation ECU 36. The power generation ECU 36 determines a required power generation output according to the output required for the motor 12, the SOC of the main battery 26, etc., and the power conversion operation by the inverter 22 (and thus the power generation operation) is performed so that the output can be obtained from the generator 20. The rotation speed of the engine 18) is controlled.

The junction box 24 is a member for setting or switching the connection relationship of the electric wiring between the in-vehicle components, and connects the contactor, the contactor or the contactor / on-vehicle component for switching the connection relationship. It is composed of wiring, various sensors, fuses, and the like. In FIG. 1, for simplification, only members related to the connection of the drive system 10, the power generation device 16 and the main battery 26 are shown. When the drive system 10 is started, the contactor represented by the symbol A in the figure is turned on in response to a command from the motor ECU 28 to connect the main battery 26 and the drive system 10. The contactor represented by the symbol B in the figure is turned on in response to a command from the power generation ECU 36 when the power generation device 16 is started, and connects the main battery 26 and the power generation device 16. Further, the fuses 38 and 40 are connected in series with the contactor A or B, and are blown and opened in a predetermined condition. In addition, the voltage sensor 42 is
The voltage V _j between the DC terminals of the contactor B is detected at a site on the side of the power generator 16 when viewed from the contactor B, and the current sensor 44 detects the DC current I _i supplied to the inverter 14 from the contactor A and the side of the drive system 10 Detected at the site. The detected voltages V _j and I _i are reported to the power generation ECU 36.

FIG. 2 shows another configuration of a hybrid vehicle suitable for implementing the present invention. In the figure, the inside of the junction box 24 is similar to that of FIG. The vehicle of this figure has an engine 18 and a motor 12
A parallel hybrid vehicle (P) is also used as a vehicle propulsion means, in other words, as a part of the drive system 10.
HV), but at the same time has a drive system 10 (in particular, a motor 12) that receives power supply and a power generator (power source) 16 independent of the main battery 26. , Has the same properties as the SHV of FIG.
The present invention is thus applicable not only to SHVs but also to vehicles of the type belonging to parallel series hybrid vehicles (PSHVs). The present invention is not limited to a vehicle that uses the generator 20 driven by the engine 18 as a power source. For example, the power generation device 16 in FIG. 1 or 2 may be realized by a solar cell, a fuel cell, or the like. Further, the contactors A and B may be connected in parallel with the charging resistor R and the contactor A ′ or B ′, respectively, as shown in FIG. In the configuration of FIG. 3, the contactors A and B are controlled by the procedure of turning on the contactors A ′ or B ′ and then turning on the contactors A or B for a while. As a result, the instantaneous inrush current due to the capacitor (not shown) between the DC terminals of the inverter 14 or 22 can be limited by the resistor R.

(2) Power Generation ECU Control Procedure FIG. 4 shows the power generation ECU 36 according to the first embodiment of the present invention.
The flow of the operation, particularly, the power generation start availability diagnosis procedure is shown. The procedure shown in this figure is executed when the power generation device 16 is connected to the main battery 26 when the power generation output is not obtained from the power generation device 16.

First, the power generation ECU 36 issues a command to the contactor B to turn it on (100). Power generation ECU
After waiting for the time required for the operation of the contactor B and the time for the transient phenomenon to settle (36), the controller 36 gives a command to the power generator 16 to start power generation (104).

However, the power generation ECU 36 uses the power generation device 16
Prior to the start of power generation, the voltage V _j is input from the voltage sensor 42 and the current I _i is input from the current sensor 44 (106).
The power generation operation is prohibited (108). That is, when the voltage V _j detected by the voltage sensor 42 is less than or equal to the predetermined failure determination threshold V _th (110), the power generation E
The CU 36 increments the built-in timer T (11
2) Then, step 106 is executed again. As a result of repeating this operation, when T reaches a predetermined value T ₀ (11
4), the power generation ECU 36 executes step 108. Therefore, in the present embodiment, when an open mode failure occurs in the contactor B, the fuse 40, or the like, this can be detected by the fact that the voltage V _j having a sufficiently high value does not appear, and by extension, the power generator 16. Can be prohibited. Before reaching T ≧ T ₀ , V _j
When ≦ V _th does not hold, the power generation ECU 36 executes step 104. After execution of step 104 or step 108, the power generation ECU 36 clears the built-in timer T (116).

Further, the power generation ECU 36 in the present embodiment.
Indicates that step 108 is executed even though the contactor B or the like is not actually in the open mode failure.
This is prevented by judging the threshold value of the current I _i . That is,
After execution of step 106, the power generation ECU 36 detects the current sensor 4
It is determined whether I _i detected in 4 is less than or equal to the detection execution threshold I _th (118). As a result, only when I _i ≦ I _th is satisfied, the power generation ECU 36 executes step 11
The process proceeds to 0, and otherwise proceeds to step 104. Therefore, in the present embodiment, the SOC of the main battery 26 is the same as when the vehicle 12 is requested to perform rapid acceleration and a large current is supplied to the motor 12.
Even when the current I _B is large in a low state, the voltage drop of the main battery 26 due to the large current discharge at the time of low SOC will not be erroneously detected as an open mode failure of the contactor B or the like. As described above, the present embodiment has an advantage that an open mode failure of the contactor B or the like can be detected without providing a micro switch or the like.
The voltage drop of the main battery 26 is mistaken for the contactor B
It has the advantage of not being detected as an open mode failure such as. As a result, in the present embodiment, for example, it is not necessary for the vehicle operator to perform an operation such as turning the ignition switch off and then turning it on again in order to cancel the operation prohibited state of the power generation device 16 due to erroneous detection. SH that power can be supplied from the power generator 16 to the main battery 26 and the drive system 10 at low SOC
The inherent benefits of V can continue to be maintained.

FIG. 5 shows a flow of the operation of the power generation ECU 36 in the second embodiment of the present invention, and particularly a portion different from the first embodiment. In this embodiment, step 11
When it is determined in step 8 that I _{i ≤I th} is satisfied, the failure determination threshold value V _thh having a relatively high value is used in step 110 (122), and conversely I _{i ≤I th.}
When it is determined that the above condition is not established, a relatively low failure determination threshold value V _thl is used in step 110 (120). Therefore, when the current I _i supplied to the drive system 10 via the junction box 24 is relatively large (here, it means that the current I _B is large because the power generation device 16 has not been operated), the failure determination is performed. Since the threshold value V _th becomes a low value, it is possible to prevent the voltage drop of the main battery 26, which is likely to occur under such a situation, from being erroneously detected as an open mode failure of the contactor B or the like.

Therefore, according to this embodiment, the same effect as that of the first embodiment can be obtained. In addition, the current I _i
It is assumed that steps 106 to 112 are repeatedly executed by the operation of the timer T while the number of times is increasing. further,
Although between current I _i is relatively small V _j ≦ V _th was satisfied, and V _j ≦ V _th is no longer satisfied when the current I _i exceeds the detection execution threshold I _th. In this case, when the current I _i is small, it can be considered that V _j ≦ V _th is established in step 110 not because of the open mode failure of the contactor B or the like but because of the voltage drop of the main battery 26. On the contrary, V _j is increased in step 110 even if the current I _i is small or large.
If ≦ V _th holds, it can be considered that the contactor B or the like is definitely in the open mode failure. Therefore, in this embodiment, it is possible to distinguish between the open mode failure of the contactor B and the like and the voltage drop of the main battery 26.

[0021]

According to the first aspect of the present invention, the power source after the command signal to the effect that the main battery and the power source should be connected is given to the contactor provided between the main battery and the power source. Prior to the start of the operation of, the voltage applied to the power source from the main battery and the current supplied to the drive system from the main battery are detected, and when the detected current exceeds the detection execution threshold, Since the detection of the open mode failure of the contactor or the like by the threshold value determination is prohibited, there is no possibility of erroneously detecting the voltage drop of the main battery due to the large current discharge at the low SOC as the open mode failure of the contactor or the like. Therefore, even in such a situation, it is possible to obtain a hybrid vehicle excellent in economic efficiency, fuel efficiency, and operability because it does not impair the original advantages of the hybrid vehicle and does not impose a burden on the vehicle operator such as ignition operation. . Furthermore, since this configuration can be realized almost by changing the control logic, it is almost unnecessary to add a device.

According to the second configuration of the present invention, instead of the open mode failure detection inhibiting means in the first configuration, when the detected current exceeds the detection execution threshold value, the failure determination threshold value is further increased. Since the value is changed to a small value, the same effect as the first configuration can be obtained. Further, since the open mode failure detection is executed by using the failure determination threshold value after the reduction correction, depending on the setting of the failure determination threshold value after the reduction correction, a large current discharge at a low SOC or the like may occur. The voltage drop of the main battery can be distinguished from the open mode failure of the contactor.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example configuration of an SHV suitable for implementing the present invention.

FIG. 2 is a block diagram showing an example configuration of a PSHV suitable for implementing the present invention.

FIG. 3 is a circuit diagram showing a modification of each contactor.

FIG. 4 is a flowchart showing a procedure of an operation of the power generation ECU according to the first embodiment of the present invention.

FIG. 5 is a flowchart showing a procedure of an operation of a power generation ECU according to the second embodiment of the present invention.

[Explanation of symbols]

10 drive system, 16 power generator (power source), 24 junction box, 26 main battery, 36 power generation E
CU, 38, 40 fuse, 42 voltage sensor, 44
Current sensor, A, B contactor, voltage applied from V _j main battery to generator, current supplied to I _i drive system, V _th , V _thl , V _thh failure determination threshold,
I _th detection execution threshold.

Claims (2)

[Claims] 1. A failure detection used in a hybrid vehicle in which a contactor for opening and closing a connection between a main battery supplying electric power to a drive system and a power source supplying electric power to the main battery is provided. In the device, after a command signal for connecting the main battery and the power source to the contactor is given, the voltage applied from the main battery to the power source and the drive system from the main battery before the operation of the power source is started. Means for detecting the current supplied to the contactor, means for detecting the occurrence of an open mode failure in the contactor or parts connected in series with the contactor because the voltage is below the failure determination threshold value, and the current And a means for inhibiting the detection of an open mode failure when the value exceeds the detection execution threshold value, the failure detection apparatus. 2. A failure detection used in a hybrid vehicle in which a contactor for opening and closing the connection between a main battery supplying electric power to a drive system and a power source supplying electric power to the main battery is provided. In the device, after a command signal for connecting the main battery and the power source to the contactor is given, the voltage applied from the main battery to the power source and the drive system from the main battery before the operation of the power source is started. Means for detecting the current supplied to the contactor, means for detecting the occurrence of an open mode failure in the contactor or parts connected in series with the contactor because the voltage is below the failure determination threshold value, and the current And a means for changing the above failure judgment threshold so that the value becomes smaller when the value exceeds the detection execution threshold than when the value falls below the detection execution threshold. Failure detection device according to claim.