JPH1198619A - Method and apparatus for detecting failure of electric car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the efficiency of inspection and repair, by omitting both detection processing of an open-circuited failure and a closed-circuit failure in lower orders to be detected secondarily at the time of failure detection of switching control devices, displaying only errors caused by primary failures, and specifying the failure spots. SOLUTION: In an MG contactor check, whether it is in the course of an MG-contactor-on command is examined (#41), and if it is not in the course of an on command whether there is an off error (a closed-circuited failure) of a running fuse or an MGFET, are examined (#46). If there is an error, checks below #47 are not excuted and the checking is stopped and returned. As the result of this, detection of failures in the lower orders to be detected secondarily is omitted. If there is no error, whether the contact of the MG contactor is in an off-state is checked (#47), and if it is in an off-state it means normal, so an abnormality counter is cleared (#50). If it is not in an off-state, it means abnormal, so an error flag is on (#49), if the abnormality counter is a specified value or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting a failure location of an electric vehicle such as a battery forklift truck.

[0002]

2. Description of the Related Art Conventionally, in this type of electric vehicle, many electromagnetic switches (contactors) are used to control a traveling motor, a hydraulic motor, and the like, and a microcomputer (MPU) controls opening and closing of the contacts of the contactor. ) Are driven by switch control elements such as transistors controlled by When detecting a failure of the contactor or the drive switch control element, the failure is detected separately, and each contactor is also detected independently.

[0003]

However, in the above-described conventional failure detection method, a failure of one driving transistor may be detected simultaneously as a secondary contact-related failure of the contactor. It occurred, and it was difficult to identify the failure location, and a serviceman spent a lot of time for inspection and repair.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a failure location of an electric vehicle capable of increasing the efficiency of inspection and repair by identifying the failure location. It is an object to provide a detection method and device.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the first aspect of the present invention, there is provided an electric motor for controlling energization of a traveling motor or the like by a circuit switch, and driving and controlling the circuit switch by a switch control element. In a failure detection method used for a vehicle and detecting a failure of a switch control element and / or a circuit switch in a time series, when a failure of the switch control element is detected, 2
The second embodiment detects both lower-level open faults and lower-level faults that are subsequently detected, and displays only errors due to primary faults.

In this method, when a failure of a switch control element is detected, whether the failure is an open failure or a closed failure, a secondary failure of a lower circuit switch corresponding to the switch control element is performed. No detection processing is performed (detection lock), and only an error display due to a primary failure is performed. That is, if the switch control element has an open fault, the circuit switch does not operate, so that when a fault is detected in the circuit switch, a fault is always detected as a secondary fault (it is regarded as a fault such as a contact failure of a contact). Is considered). If the switch control element is closed, the lower circuit switch is driven even though the switch control element is not instructed to drive the circuit switch. When the failure of the device is detected, the failure is always detected secondarily (considered as a failure such as welding of a contact). By omitting such secondary failure detection processing and detecting only an error due to a primary failure, the content of failure detection is specified, so that service personnel can perform inspection work in a short time. become.

Further, the invention of claim 2 is used in an electric vehicle in which energization to a traveling motor or the like is controlled by a circuit switch, and the circuit switch is driven and controlled by a switch control element.
In the failure detection method for detecting a failure of a switch control element and / or a circuit switch in a time series, when a failure of the circuit switch is detected, if the failure is an open failure, a lower order than that detected secondarily is detected. The failure detection process of
Only an error display due to a primary failure is performed, and if the failure is a closed failure, a lower-level failure detection process and an error display based on the failure detection are also performed.

In this method, when a failure of a circuit switch is detected, if the failure is an open failure, failure processing of a failure detection lower than that detected secondarily (such as poor contact of a contact) is performed. By omitting (detection lock) and displaying only an error due to a primary failure, an operation equivalent to that of claim 1 can be obtained. Also, in the case of a closed failure of the circuit switch, there is basically no difference from the normal operation for the lower contacts, so the failure detection process is performed without omission and the error display by the failure detection is displayed. Do.

Further, the invention according to claim 3 or 4 is used for an electric vehicle in which energization of a traveling motor or the like is controlled by a circuit switch, and the circuit switch is driven and controlled by a switch control element. In a failure detection device that detects a failure of a circuit switch in a time series, when a failure of a switch control element is detected, both detection processing of a lower-order open failure and a secondary failure that are detected secondarily is omitted, and 1
Only an error display due to a secondary failure is performed, and when a failure of the circuit switch is detected, if the failure is an open failure, the failure detection processing lower than the secondary detection is omitted and the primary detection is performed. It is provided with control means for performing only an error display due to an unusual failure, and in the case of a closed failure, performing a failure detection process at a lower level than that, and also displaying an error based on the failure detection.

In this configuration, when the open fault and the close fault of the switch control element are detected, both the open fault and the close fault lower than that detected secondarily are not detected, and the fault of the circuit switch is detected. At the time of detection, if the fault is an open fault, the lower fault detection processing is not performed below that detected secondarily, but if the fault is a closed fault, the lower fault detection processing is performed.
As a result, unnecessary failure detection processing is not performed, and a failure location can be specified. Further, the circuit switch is an electromagnetic switch having an open / close contact, which opens and closes a circuit for controlling the amateur current of the traveling motor, or drives an open / close contact that switches the direction of the field coil current. In some cases, the switch control element can be a transistor that drives and controls an electromagnetic switch.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a control circuit diagram of a forklift vehicle to which the failure detection method of the present invention is applied. The control circuit comprises an armature A of the traveling motor 1, a field winding F, and electromagnetic switches MF, M for switching between forward and reverse.
R (MF contactor, MR contactor, hereinafter the same) coils and contacts, MG contactor coils and contacts for controlling the current (including regenerative current) to the motor,
MB contactor coil and contacts, and FET or IG
It comprises a power element 2 for drive control using a BT or the like, a microprocessor (hereinafter referred to as an MPU) 3 such as a CPU for controlling the drive of a forklift vehicle, and the like. The contact of the MG contactor, the armature A, the field winding F, the control element 2 and the like are connected in series and connected to the battery BT. C1, C2, C3, C4, and C5 are voltage detection terminals for performing failure detection, and the detected voltages are input to the MPU 3. The MPU 3 controls conduction of switch control elements (hereinafter, referred to as FETs) 5, 6, 7, and 8 using FETs and the like, and thereby drives and controls each contactor. FE connected in series with the coil of the MF contactor
T5 is referred to as an MFFET, and FET8 connected in series to the coil of the MG contactor is referred to as an MGFET (others are the same).

A flywheel diode D for flowing a regenerative current or an inertial current of the motor is provided in the control circuit.
1, D2, D3, current sensors IA and IF for detecting an armature current and a field current and input to the MPU 3, fuses F1 and F2, a key switch KS, and the like. The MPU 3 includes a ROM 9 storing a program for performing a self-diagnosis and other processes described later, and a display device 10 such as an LCD for monitoring and displaying the results of the self-diagnosis and other processes.
Is connected. Although not shown, an input device for inputting travel and operation commands to the MPU 3, a hydraulic motor for a forklift driven and controlled by the MPU 3, and a control circuit therefor are also provided.

In the control circuit for a battery forklift constructed as described above, when the traveling accelerator is tilted forward, the MPU 3 first drives the MG contactor of the traveling motor 1 and then drives the MG contactor. The MF contactor for switching the field coil is driven, and finally, a chopper command is output to the power element 2 for controlling the motor current. With this operation, the forklift starts moving forward. Speed control is performed by chopper control of the mature current. The coil of the MG contactor is excited by the FET 8 that has received the drive signal from the MPU 3. At that time, MP
U3 performs a failure detection (self-diagnosis) of the various FETs and contactors in a time series in a predetermined procedure as described below.

FIG. 2 is a flowchart of a self-diagnosis process in the main program of the MPU 3, and FIG. 3 is a diagram showing a check procedure for detecting a failure in a part of the self-diagnosis process.
In the self-diagnosis process, when all the predetermined error check processes (# 2) set in advance are performed (YES in # 1),
Exit from this process. MGFET in the self-diagnosis process
Check (# 11: FIG. 4), MG contactor check (# 12: FIG. 5), MFFET check (# 13), M
F contactor check (# 14: Fig. 6) for 20msec
Perform each time series. In any case, priority is given to FET failure detection over corresponding contactor failure detection.

Hereinafter, a method of detecting a failure by self-diagnosis will be described. Now, the FET 8 for driving the MG contactor
However, when an open failure occurs, no current flows through the coil of the MG contactor, and the contact of the MG contactor does not turn on. Therefore, in FIG. 1, the battery voltage is not applied to the C2 terminal. The voltage of each part is input to the MPU 3 as a signal from each terminal of C1, C2, C3, C4, and C5.

Here, under the condition that no voltage is applied to the terminal C2 despite the fact that the MG contactor has been driven, the MPU 3 has determined that the MG contactor is abnormal in the conventional failure detection method. Further, since the MF contactor is turned on in this state, no battery voltage is applied to the C3 terminal, and the MPU 3 has also determined that the MF contactor is abnormal. Therefore, the MG contactor driving FET 8
When an open failure occurred, the error of "transistor (regenerative contactor)", "contactor (regenerative)", and "contactor (forward)" was detected and displayed. for that reason,
The serviceman took a long time to find the failure.
Further, when a close failure occurs in the MG 8 for driving the MG contactor, the MG contactor is driven although the MPU 3 does not drive the MG contactor.
Voltage is applied to two terminals. This is MPU3 M
It was judged that the welding of the G contactor was abnormal, and an error of “transistor (regeneration contactor)” and “contactor (regeneration)” was displayed. As a result, the serviceman took a long time to find the failure location.

Therefore, in the present embodiment, when a contactor driving transistor has an open fault or a closed fault, it is always detected in a secondary manner so that a serviceman can specify a fault location in a short time. Such errors are ignored by software in advance, and the error display is made only by "transistor (regeneration contactor)" to improve serviceability. The same applies to other contactors.

FIGS. 4 to 6 are flowcharts of various failure detection checks. In the MGFET check of FIG. 4, it is determined that the MGFET (8) is OFF, and if it is not abnormal, the abnormality count is cleared (# 22) and the error flag is turned off (# 23). Then, the ON check abnormality of the MGFET (8) is determined (# 27), and if it is not abnormal, the same processing (# 28, # 29) as the above # 22, # 23 is performed, and the process returns to the main program. If it is determined in # 21 that there is an abnormality, it is checked whether the abnormality count is equal to or greater than a predetermined value (here, 8) (# 21).
24) If it is not equal to or more than the predetermined value, the abnormality count is incremented (# 25). If it is equal to or more than the predetermined value, an error flag (close failure) is turned on (# 26) and the process proceeds to # 27.
If it is determined in step # 27 that there is an abnormality, the same processing as in steps # 24 to # 26 (# 30 to # 32) is performed, the error flag (open fault) is turned on in step # 32, and the routine returns.

In the above, the reason why the abnormality count is set to 8 or more is that if an error has occurred for 20 msec × 8 = 160 msec, it is determined that an abnormality has occurred (prevention of erroneous detection). In the following description, there are cases where the abnormal count is 10 or more and 12 or more. However, since it is not known which routine the error occurs during processing, no matter where the error occurs, eight errors are detected first. This is to be determined first. Errors with a small number are the highest priority detection targets.

Next, in the MG contactor check of FIG. 5, it is checked whether the MG contactor ON command is being issued (# 4).
1) If not ON command, running fuse or MGF
It is checked whether an ET / OFF error (close failure) has occurred (# 46). If the error has occurred, this subroutine does not perform the checks of # 47 and below (software failure detection lock) and returns. I do. This gives M
The G contactor, i.e., the secondary failure detection of lower faults is omitted. If the error has not occurred in # 46, the contact OFF of the MG contactor is checked (# 4
7) If OFF, the counter is normal, and the abnormal counter is cleared (# 50). If it is not OFF, it is an abnormality, so it is checked whether the abnormality counter is equal to or more than a predetermined value (here, 10) (# 48). For example, the error flag (close failure) is turned ON (# 49), and the process returns.

In step # 41, if the MG contactor ON command is being issued, it is checked whether a running fuse or an MGFET ON error (open failure) has occurred (# 42).
If the error has occurred, the subroutine # 4
3 or less is not checked (failure detection lock by software), and the routine returns. As a result, similarly to the above, the MG contactor, that is, lower-order failure detection that is detected secondarily is omitted. If the error has not occurred in # 42, the contact ON of the MG contactor is checked (# 4
3) If ON, the counter is normal, and the abnormal counter is cleared (# 52). If it is not ON, it is abnormal.
It is checked whether the abnormality counter is equal to or more than a predetermined value (here, 10) (# 44). If the abnormality counter is not equal to or more than the predetermined value, the abnormality counter is counted up (# 53). After turning ON (# 45), the routine returns.

Next, in the MF contactor check shown in FIG. 6, it is checked whether the MG contactor ON instruction is being issued (# 6).
1) If the instruction is not ON, the routine exits from this routine and the subsequent processing is not performed. If the MG contactor ON command is being issued, it is checked whether the MF contactor ON command is being issued (# 62).
If the N instruction is not being performed, the process exits from this routine. If the ON instruction is being issued, it is checked whether a traveling fuse error has occurred (# 63).
If the error is the same, the process exits the routine. If the error is not the MGFET ON error (open failure) (# 64), the process exits the routine if the error is ON. If it is not the ON error, it is checked whether the MG contactor is ON (# 65). If it is the ON error (open fault), the process exits from this routine. If it is not the ON error, it is the MFFET ON error (open fault). Is checked (# 66). If the error is the same, the process exits from this routine. If not ON error, MRFET OFF
Check for an error (close failure) (# 67), turn OFF
If there is an error, the process exits from this routine. If it is not the same OFF error, it is checked whether the MF contactor contact is abnormal (# 6)
8).

If the contact of the MF contactor is not abnormal in # 68, the abnormality count is cleared (# 71). If the contact of the MF contactor is abnormal, it is checked whether the abnormality count is equal to or more than the predetermined value (12) (# 69). If it is not equal to or more than the predetermined value, the abnormality count is incremented (# 72).
The error flag is turned on (# 70). In this way, if an open failure error has occurred in the MF contactor, the error check of the lower contactor is not performed thereafter (detection is locked), and if a close failure has occurred, the lower contactor cannot be used. Since the operation is basically the same as the normal operation, the subsequent error check is performed (the detection is not locked).

With the above error check, it is possible to specify a failure location, and basically, only one error display is provided to improve serviceability.

The present invention is not limited to the configuration of the above embodiment, and various modifications are possible. For example, in the above-described embodiment, an example of error checking of some FETs and contactors has been described, but the present invention can be similarly applied to failure detection of other contactor-related components.

[0026]

As described above, according to the first aspect of the present invention,
When the failure of the switch control element is detected, whether the failure is an open failure or a closed failure, the secondary failure detection processing of the lower circuit switch corresponding to the switch control element is not performed and the primary failure is not performed. By performing only an error display due to a temporary failure, unnecessary secondary lower-level failure detection processing can be omitted, and the failure detection content can be specified.
The efficiency of inspection work by service personnel can be improved.

According to the second aspect of the present invention, when the failure of the circuit switch is detected as an open failure,
By omitting the failure detection processing lower than that detected secondarily and displaying only the error due to the primary failure,
The same operation as above can be obtained, and in the case of a closed failure of the circuit switch, by performing the failure detection processing without omitting, there is no difference from the normal operation for the lower contacts, so it is correct. Failure detection becomes possible.

Further, according to the third and fourth aspects of the present invention, it is possible to provide an apparatus capable of achieving both the effects of the first and second aspects of the present invention.

[Brief description of the drawings]

FIG. 1 is a control circuit diagram of a forklift vehicle to which a failure detection method according to the present invention is applied.

FIG. 2 is a flowchart of a self-diagnosis process of the MPU.

FIG. 3 is a diagram showing a check procedure of a part of failure detection in the self-diagnosis processing.

FIG. 4 is a flowchart of an MGFET check.

FIG. 5 is a flowchart of an MG contactor check.

FIG. 6 is a flowchart of an MF contactor check.

[Explanation of symbols]

 Reference Signs List 1 traveling motor 3 microprocessor 5, 6, 7, 8 FET 10 display device MF, MR electromagnetic switch (contactor: circuit switch)

Claims (4)

[Claims] The present invention is used in an electric vehicle that controls the energization of a traveling motor and the like by a circuit switch and controls the drive of the circuit switch by a switch control element, and detects a failure of the switch control element and / or the circuit switch. In the failure detection method for detecting in time series, when detecting a failure of the switch control element, both detection processing of a lower-order open failure and a closed failure that are secondary detected are omitted, and only an error display due to a primary failure is displayed. A method for detecting a failure of an electric vehicle. 2. An electric vehicle in which energization of a traveling motor or the like is controlled by a circuit switch, and the circuit switch is driven and controlled by a switch control element, and a failure of the switch control element and / or the circuit switch is determined. In the failure detection method for detecting in time series, when the failure of the circuit switch is detected as an open failure, a failure detection process lower than the secondary failure is detected and the primary failure is detected. A failure detection method for an electric car, characterized in that only an error display due to a specific failure is performed, and if the failure is a closed failure, a lower failure detection process and an error display based on the failure detection are also performed. 3. An electric vehicle in which energization of a traveling motor or the like is controlled by a circuit switch, and the circuit switch is driven and controlled by a switch control element, and a failure of the switch control element and / or the circuit switch is determined. In the failure detection device that detects in a time series, when a failure of the switch control element is detected, detection processing of both lower-order open failures and closed failures that are detected secondarily is omitted, and only an error display due to a primary failure is displayed. When a failure of the circuit switch is detected, if it is an open failure, the lower failure detection processing lower than that detected secondarily is omitted and only the error display due to the primary failure is displayed. The electric vehicle is provided with control means for performing a lower-level failure detection process if the failure is a close failure and displaying an error based on the failure detection. Disabled detection device. 4. The circuit switch, which is an electromagnetic switch having an open / close contact, opens and closes a circuit for controlling an amateur current of a traveling motor, or drives an open / close contact that switches a direction in which a field coil current is supplied. The failure detection device for an electric vehicle according to claim 3, wherein the switch control element is a transistor that drives and controls the electromagnetic switch.