JP2730354B2 - Fault diagnosis device in DC motor drive control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure diagnosis device for a drive control device of a DC motor.

[0002]

2. Description of the Related Art Conventionally, an electric vehicle using a battery such as a battery-powered forklift is driven and controlled by a drive circuit shown in FIG.

The drive motor 21 is a regenerative contactor 2
2 and a drive fuse 23 are connected to a battery 24 as a DC power supply. The drive motor 21 is a series-wound DC motor and drives a drive wheel (not shown) of an electric vehicle.

The field coil 2 of the drive motor 21
1a includes a forward contactor 25 as a switching means.
f and the reverse contactor 25r are connected, and based on the switching operation of the two contactors 25f and 25r, the direction of the field current flowing through the field coil 21a is changed to rotate the drive motor 21 in the forward and reverse directions. It is going to advance.

A main transistor 26 as a switching element is connected in series to the drive motor 21, and the drive of the drive motor 21 is controlled based on a known chopper signal input to its base terminal.

The bypass contactor 27 is connected in series to the drive motor 21,
The drive of the drive motor 21 is controlled by opening and closing the drive.

Therefore, the drive of the drive motor 21 is controlled by two systems of the main transistor 26 and the bypass contactor 27. That is, when the electric vehicle is traveling at a low speed, the bypass contactor 27 is dropped. The main transistor 26 performs a switching operation based on the chopper signal, and a current is supplied from the battery 24 to the drive motor 21 in accordance with the switching operation, and the drive motor 21 is driven.
The electric vehicle can run at an arbitrary speed based on the chopper control. On the other hand, when traveling at high speed, the bypass contactor 27 is turned on. Then, regardless of the switching operation of the main transistor 26, the drive motor 2
1 is supplied with current and driven.

The anode terminal of the flywheel diode 28 is connected to the forward contactor 25 of the field coil 21a.
f side, the cathode terminal is a drive fuse 2
3 is connected to the plus terminal of the battery 24. The anode terminal of the flywheel diode 29 is connected to the reverse contactor 25r of the field coil 21a.
Side, and the cathode terminal is a drive fuse 23
Is connected to the plus terminal of the battery 24 via the.

The drive current sensor 30 is connected between the armature 21b of the drive motor 21 and the regenerative contactor 22, and detects a current flowing through the armature 21b.

The cathode terminal of the regenerative diode 31 is connected to the regenerative contactor 22, and the anode terminal is connected to the negative terminal of the battery 24. The collector of the regenerating transistor 32 is connected to the positive terminal of the battery 24 via the driving fuse 23, and the emitter is connected to the forward / backward contactors 25f and 25r of the armature 21b via the regenerating register 33. Then, a regeneration control signal is input to a base terminal of the regeneration transistor.

The regenerative contactor 22, forward / backward contactors 25f and 25r, and bypass contactor 27 are respectively opened and closed by exciting coils (not shown). These exciting coils are switched control means, inhibition control means, and voltage applying means. And the excitation is controlled by the control circuit 40. Also, the chopper signal of the main transistor 26 and the regeneration control signal of the regeneration transistor 32 are
It is output from the control circuit 40.

That is, when the forward and reverse contactors 25f and 25r are switched by switching back of the electric vehicle, the control circuit 40 checks whether regenerative braking is possible or not and releases the regenerative contactor 22 when it is determined that regenerative braking is performed. The regeneration transistor 32 is turned on. Then, the pre-excitation current from the battery 24 via the drive fuse 23, the regeneration transistor 32, the regeneration register 33, the forward or reverse contactors 25f, 25r, the field coil 21a, the reverse or forward contactors 25r, 25f, and the main transistor 26. I1 flows. When the pre-excitation current I1 flows through the field coil 21a, an electromotive force E is generated in the armature 21b in the direction of the arrow VA in FIG. When the electromotive force E exceeds a certain value, the pre-excitation current I1
And the pre-excitation current I2 starts to flow through the regenerative diode 31. When the pre-excitation current I2 increases, the pre-excitation current I1 flowing through the field coil 21a increases, and the electromotive force E also increases. Then, as the electromotive force E increases, the pre-excitation current I2 further increases. When the pre-excitation current I2 becomes larger than a certain level, the control circuit 40 turns off the regeneration transistor 32. Then
The pre-excitation current I1 stops flowing, but the pre-excitation current I2
Tries to keep flowing.

Next, when the main transistor 26 is turned off, the regeneration diode 31 and the drive current sensor 3
0, amateur 21b, forward or reverse contactor 25
The regenerative current I3 flows in the direction of charging (regenerating) the battery 24 via the f, 25r, the field coil 21a, the reverse or forward contactors 25r, 25f, the flywheel diode 29 or 28, and the drive fuse 23. Subsequently, when the main transistor 26 is turned on,
The pre-excitation current I2 flows, and then when the main transistor 26 is turned off, the regenerative current I3 flows.

As described above, according to the switching operation of the main transistor 26, the pre-excitation current I2 and the regenerative current I2
3 alternately flows. Thereby, the drive motor 21
The generated power is regenerated to the battery 24, and the drive motor 21 is subjected to braking corresponding to the current, that is, regenerative braking.

The anode terminal of the absorber diode 34 is connected to the collector terminal of the main transistor 26,
The cathode terminal is connected to a negative terminal of the battery 24 via an absorber capacitor 35. The absorber resistor 36 is connected in parallel with the absorber diode 34. A known CRD snubber circuit 37 including the absorber capacitor 35, the absorber resistor 36, and the absorber diode 34 absorbs a surge voltage generated by an inductance component in the wiring due to the switching operation of the main transistor 26.

The control circuit 40 has a check function just before starting. That is, by connecting the collector terminal of the main transistor 26 to the plus terminal of the battery 23 via the check register 41 and the check fuse 38, the control circuit 40 applies the detection voltage to the collector terminal of the main transistor 26. Has become. The collector potential of the main transistor 26 is detected by a voltage detection circuit 39 provided in the control circuit 40. Based on the detected collector potential of the main transistor 26, the control circuit 40 provides the regenerative contactor 22 and the forward / backward contactor 25f,
Permission or prohibition of 25r insertion is controlled.

That is, if the collector and the emitter of the main transistor 26 are short-circuited, it becomes impossible to perform low-speed running by chopper control, and high-speed running is performed even when the bypass contactor 27 is separated. Therefore, even when the driver selects the low-speed running and starts, the high-speed running may be performed. Therefore, the control circuit 40 checks whether the collector and the emitter of the main transistor 26 are short-circuited at the time of starting the electric vehicle.

FIG. 4 is a control flowchart of the control circuit 40. When the electric vehicle is started, the regenerative contactor 22, the forward / reverse contactors 25f and 25r, and the bypass contactor 27 are all separated. Therefore, in step (hereinafter, S) 1, a detection voltage is applied to the collector terminal of the main transistor 26 via the control circuit 40,
The collector potential at that time is detected by the voltage detection circuit 39, and it is determined whether or not the potential is equal to or higher than a predetermined value. If the collector and the emitter of the main transistor 26 are short-circuited, the collector potential becomes 0 V, so that the flow shifts to S2. Also, in the case of a state close to a short circuit, the process similarly shifts to S2. In S2, the turning on of the regenerative contactor 22 and the forward / reverse contactors 25f, 25r is prohibited, and a warning lamp (not shown) is used to notify the driver of the electric vehicle that the main transistor 26 is short-circuited. I do.

If the collector potential of the main transistor 26 is equal to or higher than a predetermined value, the flow shifts to S3,
Regeneration contactor 22 and forward / backward contactor 25
f, 25r are permitted to be input. Accordingly, the driver turns on the regenerative contactor 22, and the forward / backward contactor 25f,
The electric vehicle can run at low speed by inputting any of 25r.

The check register 41 and the check fuse 38 prevent the battery 24 from being short-circuited and an overcurrent from flowing when the collector-emitter of the main transistor 26 is short-circuited or when the bypass contactor 27 is turned on.

[0021]

The control circuit 4
0 confirms that the collector-emitter of the main transistor 26 is not short-circuited, and after the turning-on of the regenerative contactor 22 is permitted, the regenerative diode 31 is short-circuited when the driver turns on the regenerative contactor 22. If it has, the drive fuse 2
3. A short-circuit current flows via the regeneration contactor 22 and the regeneration diode 31. Then, the drive fuse 23 is blown or the contact of the regenerative contactor 22 is burned.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to diagnose whether at least one of the switching element and the regenerative diode has failed before starting the drive motor. A fault diagnosis device is provided by a simple configuration.

[0023]

A DC motor, switching means for switching the field coil wiring of the DC motor and switching its excitation direction, and a DC motor connected between the DC motor and the negative terminal of the DC power supply. A switching element that controls the conduction and non-conduction of the DC power supply to drive the DC motor, and is connected between the plus terminal of the DC power supply and the DC motor, and is used for regenerative braking to open the circuit and apply regenerative braking to the DC motor. The anode is connected to the contactor and the negative terminal of the DC power supply, the cathode is connected between the DC motor and the regenerative contactor, and the regenerative current of the DC motor is supplied to the DC power supply via the DC motor when the regenerative contactor is opened. A DC motor drive control device having a regenerative diode for returning In the state where the contactor is open, the switching means switches the field coil wiring from the non-conductive state to the energized state in one of the excitation directions by the switching means, and the switching element in the state where the field coil wiring is switched. A voltage application unit for applying a detection voltage between the regenerative diode, and a detection voltage applied by the voltage application unit, and if the detection voltage is smaller than a predetermined value, at least one of the switching element and the regenerative diode A failure diagnosis device in a drive control device of a DC motor, comprising: a prohibition control unit that prohibits start-up as a failure.

[0024]

Before starting the start of the DC motor, the regenerative contactor is in an open state. Therefore, the switching control means controls the switching means to switch the field coil wiring from the non-conductive state to the energized state in one of the exciting directions. Then, a detection voltage is applied between the switching element and the regenerative diode by the voltage applying means. The prohibition control means controls the starting by detecting the detection voltage. That is, if the detected voltage is equal to or higher than a predetermined value, it is determined that both the switching element and the regenerative diode have not failed, and the start is permitted. If the detected voltage is smaller than a predetermined value, the start is prohibited because it is determined that at least one of the switching element and the regenerative diode has failed.

Therefore, according to the present invention, it is possible to easily diagnose whether at least one of the regenerative diode and the switching element has failed.

[0026]

【Example】

(First Embodiment) A first embodiment of the present invention will be described below with reference to FIGS.

It should be noted that the present embodiment has the same configuration as the conventional example except that the control operation of the control circuit 40 is different.
The detailed description of the configuration is omitted, and the control operation of the control circuit 40 will be described according to the control flowchart shown in FIG.

When the electric vehicle is started, the regenerative contactor 22, the forward / reverse contactors 25f and 25r, and the bypass contactor 27 are all separated. Therefore, S10
In the main transistor 2 via the control circuit 40,
6, a detection voltage is applied to the collector terminal, and the collector potential at that time is detected by the voltage detection circuit 39 to determine whether or not the voltage is equal to or higher than a predetermined value. When the collector and the emitter of the main transistor 26 are short-circuited,
Since the collector potential becomes 0 V, the flow shifts to S11. Also, in the case of a state close to a short circuit, the process similarly shifts to S11.
In S11, the rejection of the regenerative contactor 22 and the forward / reverse contactors 25f and 25r is prohibited, and
Using a warning lamp (not shown) or the like, the driver of the electric car is notified that the main transistor 26 is short-circuited.

If the collector potential of the main transistor 26 is equal to or higher than a predetermined value, the flow shifts to S12 to permit the forward and reverse contactors 25f and 25r to be turned on. Then, the control circuit 40 energizes the corresponding exciting coil to turn on one of the forward and reverse contactors 25f and 25r, and shifts to S13.

In S13, similarly to S10, the collector potential of the main transistor 26 is detected by the voltage detection circuit 39, and it is determined whether or not the voltage is equal to or higher than a predetermined value.

When the regenerative diode 31 is short-circuited, the collector terminal of the main transistor 26 includes the forward or backward contactors 25f, 25r, the field coil 21a, the backward or forward contactors 25r, f, the amateur 21b, and the drive current sensor. 30, and is connected to the minus terminal of the battery 24 via the short-circuited regeneration diode 31. Since the resistance value of this path is so small as to be negligible compared to the resistance values of the check register 41 and the check fuse 38, the collector potential of the main transistor 26 becomes almost 0V. Therefore,
Move to S14. Also, when the regenerative diode 31 is in a state of being short-circuited, the process similarly proceeds to S14. In S14, the turning on of the regenerative contactor 22 is prohibited, and the driver is informed that the regenerative diode 31 is short-circuited using a warning lamp (not shown) or the like.

If the collector potential of the main transistor 26 is equal to or higher than a predetermined value, the process shifts to S15, and the forward or reverse contactor 25, which is turned on in S12, is turned on.
f, 25r are dropped off, and the input of the regenerative contactor 22 is permitted. Therefore, when the driver operates the forward / reverse lever (not shown) and turns on one of the forward / backward contactors 25f and 25r and the regenerative contactor 22, the electric vehicle can run at low speed.

As described above, in the above embodiment, after confirming that the collector and the emitter of the main transistor 26 are not short-circuited, the forward or backward contactors 25f and 25r are turned on, and then the main transistor 26 is again turned on. By detecting the collector potential of 26, it is possible to detect whether or not the regenerative diode 31 has a short-circuit failure.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. In this embodiment, since the configuration is the same as that of the conventional example except that the control operation of the control circuit 40 is different, detailed description of the configuration is omitted, and the control operation of the control circuit 40 is performed according to the control flowchart shown in FIG. Will be described.

When the electric vehicle is started, the regenerative contactor 22 is off. Then, in S20, the control circuit 40 first turns on one of the forward and reverse contactors 25f and 25r. Subsequently, in S21, a detection voltage is applied to the collector terminal of the main transistor 26 via the control circuit 40, and the collector potential at that time is detected by the voltage detection circuit 39, and it is determined whether or not the voltage is equal to or higher than a predetermined value. . When the collector-emitter of the main transistor 26 or at least one of the regenerative diodes 31 is short-circuited, the collector potential becomes 0.
V, so the flow shifts to S22. Also, in the case of a state close to a short circuit, the process similarly proceeds to S22. In S22,
The turning on of the regenerative contactor 22 is prohibited, and a warning lamp (not shown) is used to notify the driver of the electric vehicle that at least one of the main transistor 26 and the regenerative diode 31 is short-circuited.

If the collector potential of the main transistor 26 is equal to or higher than a predetermined value, the process proceeds to S23, in which the forward or reverse contactors 25f and 25r, which have been turned on at the time of starting, fall off, and the regenerative contactor 2
2 is allowed. Therefore, when the driver operates the forward / reverse lever and turns on one of the forward / backward contactors 25f and 25r and the regenerative contactor 22, the electric vehicle can run at low speed.

As described above, in the above embodiment, at least one of the main transistor 26 and the regenerative diode 31 is detected by detecting the collector potential of the main transistor 26 after the forward or reverse contactors 25f and 25r are turned on. It is possible to detect whether or not there is a short circuit failure.

Note that the present invention is not limited to the above embodiment, and may be embodied in, for example, an apparatus using a DC motor as well as an electric car.

[0039]

As described above in detail, according to the present invention, by diverting a conventional device without adding a special device, it is possible to determine whether at least one of the switching element and the regenerative diode has failed. There is an excellent effect that can diagnose.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram showing a drive circuit of an electric vehicle according to one embodiment of the present invention.

FIG. 2 is a flowchart illustrating a control process of a control circuit according to the first embodiment.

FIG. 3 is a flowchart illustrating a control process of a control circuit according to a second embodiment.

FIG. 4 is a flowchart showing a control process of a control circuit of a conventional example.

[Explanation of symbols]

21: Drive motor, 21a: Field coil, 2
2: Regeneration contactor, 25f: Forward contactor, 2
5r: reverse contactor, 26: main transistor,
31: regeneration diode, 40: control circuit

Claims (1)

(57) [Claims] 1. A DC motor, a switching means for switching a field coil wiring of the DC motor and an excitation direction thereof, and connected between the DC motor and a minus terminal of the DC power supply for conducting the DC power supply of the DC motor. A switching element that controls non-conduction to drive the DC motor, and is connected between the plus terminal of the DC power supply and the DC motor;
A regenerative contactor for opening and applying regenerative braking to the DC motor, an anode is connected to the negative terminal of the DC power supply, and a cathode is connected between the DC motor and the regenerative contactor,
A drive control device for a DC motor including a regenerative diode for returning a regenerative current of the DC motor to the DC power supply via the DC motor when the regenerative contactor is opened. In the state where the contactor is open, the switching means switches the field coil wiring from the non-conductive state to the energized state in one of the excitation directions by the switching means, and in the state where the field coil wiring is switched,
Voltage applying means for applying a detection voltage between the switching element and the regenerative diode; detecting the detection voltage applied by the voltage applying means, and if the detected voltage is smaller than a predetermined value, the switching element or the regenerative diode. And a prohibition control means for prohibiting starting as a failure of at least one of the above.