JPH08212895A - Failure detecting device for switch means - Google Patents

Abstract

PURPOSE: To provide a failure detecting device for switch means in which the erroneous operation or breakage of an equipment caused by the abnormal function of a switch means such as relay by a failure after the operation of a device can be surely prevented. CONSTITUTION: A controller 2 supplies a prescribed current command value to a motor driving part 1 in the state where off is instructed to a relay 3 before the operation of a device. The current carried in a motor M is detected by a current sensor 4. The controller 2 examines whether the relay 3 is fused or not depending on the presence or absence of the current detected by the current sensor 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier vehicle,
The present invention relates to a failure detection device for switch means suitable for use in a motor drive circuit that supplies power to an electric vehicle such as an electric vehicle or a human powered vehicle with auxiliary power.

[0002]

2. Description of the Related Art Conventionally, in an electric vehicle such as a carrier vehicle, an electric vehicle, and a manpowered vehicle with auxiliary power, a relay is used for the purpose of protecting a power supply circuit for driving the motor from an electrical abnormality such as a short circuit. ing. That is, when an abnormality such as a short circuit occurs, an overcurrent flows in the motor or the circuit, which may cause a malfunction of the device or a mechanical failure such as damage of an IC (Integrated Circuit). A method is adopted in which a relay is inserted between the power supply side and the motor, and the relay is turned off in response to the detection of an abnormality to prevent an overcurrent from flowing.

[0003]

By the way, the relay used as a safety device as described above is shipped after being subjected to a predetermined functional inspection such as whether or not the ON / OFF operation is normally performed. It will not normally be inspected once it has been installed in. For this reason, for example, if a spark is generated during operation of the equipment and the relay is welded and fixed in the ON state, the relay itself, which is a safety device, will not function, and the above-mentioned short circuit or other abnormality will occur. Sometimes it is impossible to avoid overcurrent.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to reliably prevent malfunction or damage of equipment due to malfunction of switch means such as a relay and malfunction of the equipment during operation of the equipment. An object of the present invention is to provide a failure detection device for switch means that can be used.

[0005]

In order to solve the above-mentioned problems, the present invention provides an energizing means for supplying a current corresponding to a given command value to a motor, and a connecting means for connecting the energizing means and the motor. A failure detection device for a switch means applied to a motor drive device, comprising: a switch means that is inserted in an electric path and switches to a conductive / non-conductive state in response to an on / off command. Before operation of the apparatus, a predetermined inspection command value is supplied to the energizing means to instruct energization, and a switch for issuing an off command to the switch means while energization is instructed by the energizing instruction means. Energization is instructed by the control means, the current detection means for detecting the current flowing in the motor, and the energization instructing means, and the switch control means issues an off command. In the meantime, when a current is detected by the current detecting means, an abnormality determining means for determining that the switch means is abnormal, and when the abnormality determining means determines an abnormality, the energization of the motor is stopped. And an abnormality processing means for notifying that there is an abnormality.

According to the present invention, the energization instructing means supplies a predetermined inspection command value to the energizing means to instruct energization before the operation of the motor drive device, and the switch control means energizes the energizing instructing means. While instructed, an off command is issued to the switch means, the current detection means detects the current flowing through the motor, and the abnormality determination means is instructed to energize by the energization instructing means, and the switch control means issues an off command. While the current is detected by the current detection means,
The switch means is determined to be abnormal, and the abnormality processing means
The power to the motor is stopped and the fact that there is an abnormality is reported. Accordingly, even if an abnormality of the switch means such as welding of a relay occurs after the switch means is incorporated in the motor drive device, it is possible to determine the presence or absence of this abnormality. Then, the operator can know such an abnormality of the switch means before the operation of the motor drive device. After that, by repairing or replacing the relay, it is possible to prevent the motor from being adversely affected.

Alternatively, an energizing means for supplying a current corresponding to a given command value to the motor and an energizing path connecting the energizing means and the motor are connected to each other so as to be conductive / non-conductive according to an on / off command. In a failure detecting device for a switch means applied to a motor driving device comprising a switch means for switching to any state, a predetermined inspection command value is given when an OFF command is issued to the switch means. Is supplied to the energizing means to instruct energization, a current detecting means for detecting a current flowing in the motor, and an energizing instruction by the energizing instructing means,
It may be a failure detecting device for switch means, which comprises an abnormality determining means for determining that the switch means is abnormal when the current is detected by the current detecting means.

In this case, the energization instructing means supplies a predetermined inspection command value to the energizing means to instruct energization when the switch means is instructed to turn off, and the current detecting means Detecting the current flowing through the motor, the abnormality determining means determines that the switch means is abnormal when the current is detected by the current detecting means while the energization instructing means instructs the energization. Accordingly, even if an abnormality of the switch means such as welding of a relay occurs after the switch means is incorporated in the motor drive device, it is possible to determine the presence or absence of this abnormality. Then, when the switch unit is instructed to turn off and the motor is not driven, the abnormality determination is performed. When an abnormality is determined, for example, it may be notified to the outside or the energization of the motor may be stopped. After this,
Repairing or replacing the relay can prevent the motor from being adversely affected.

[0009]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. (1) First Embodiment FIG. 1 is a block diagram showing the configuration of a failure detecting device for switch means according to a first embodiment of the present invention. The failure detecting device for the switch means is applied to a bicycle with auxiliary power (not shown). In a bicycle with auxiliary power, a current (or voltage) that is almost proportional to the pedal effort is supplied from a secondary battery to a motor, and the bicycle is driven by a combined driving force of the motor power and human power.

In the figure, E is a secondary battery, which is constructed by connecting a plurality of battery cells such as a sealed lead battery and a sealed NiCd battery in series. Reference numeral 1 is a motor drive unit that controls the current supplied to the motor M. This motor drive unit 1
Supplies to the motor M a current corresponding to the pulse width of a PWM (Pulse Width Modulation) wave given from the controller 2 (described later) as a current command value based on the discharge current supplied from the secondary battery E.

Reference numeral 3 is a relay, which is inserted in a current path from the motor drive unit 1 to the motor M as a safety device for shutting off an overcurrent. That is, the relay 3 is in the ON state at the time of normal energization, but is turned off at the time of occurrence of an abnormality such as a short circuit, so that the overcurrent is prevented from flowing. In the present embodiment, in order to detect this when the relay 3 is fixed in the ON state by welding or the like,
An inspection (described later) by the controller 2 is performed before the operation of the bicycle with auxiliary power.

A current sensor 4 detects the actual current flowing in the motor M and outputs a detection signal corresponding to the magnitude of this current to the controller 2.

The controller 2 is composed of hardware such as an input interface 2f and output interfaces 2g and 2h in addition to a CPU and a memory (not shown), and its software configuration includes a current detection section 2a, a relay abnormality determination section 2b, and It comprises a relay ON / OFF command section 2c, a current command calculation section 2d and a PWM wave calculation section 2e.

The current detector 2a is an input interface 2
The current detection value that has been A / D (analog / digital) converted via f is measured, and the measurement result is used as the relay abnormality determination unit 2
Output to b. The relay abnormality determination unit 2b determines whether or not the relay 3 is abnormal based on the measurement result of the actual current supplied from the current detection unit 2a when the relay 3 is instructed to turn off and a predetermined current command value is given. To judge.

The relay ON / OFF command section 2c controls ON / OFF of the relay 3 in accordance with the ON / OFF command supplied from the relay abnormality determination section 2b. The current command calculator 2d
The current command value is calculated according to the energization command supplied from the relay abnormality determination unit 2b. The PWM wave calculation unit 2e generates a PWM wave having a pulse width corresponding to the current command value supplied from the current command calculation unit 2d. The motor drive unit 1 is moved by this PWM wave.

Incidentally, the relay abnormality judging section 2b is constituted by the relay 3
When it is determined that is abnormal, the current command calculation unit 2d is instructed to stop energizing the motor M. Also,
At this time, the relay abnormality determination unit 2b turns on the warning light 5 and causes the warning buzzer 6 to generate a warning sound via the output interfaces 2g and 2h.

Next, the operation of this embodiment will be described. FIG. 2 is a flowchart showing the operation of the controller 2 that inspects the relay 3 before the operation of the bicycle with auxiliary power. The operation of the embodiment will be described below with reference to this flowchart.

First, when the power is turned on and the system is activated, the controller 2 advances the processing to step ST1. In step ST1, the relay abnormality determination unit 2b issues an OFF command to the relay ON / OFF command unit 2c. As a result, the relay 3 is turned off if there is no abnormality such as welding.

Next, in step ST2, the relay abnormality determination unit 2b issues an energization command to the current command calculation unit 2d.
As a result, the current command calculator 2d calculates a predetermined inspection command value, and the PWM wave calculator 2e generates a PWM wave corresponding to this command value. Then, this PWM wave is supplied to the motor drive unit 1, and a current corresponding to the pulse width is output to the motor M.

Next, in step ST3, the current detector 2a measures the current value supplied from the current sensor 4,
The measurement result is output to the relay abnormality determination unit 2b. In step ST4, the relay abnormality determination unit 2b causes the current detection unit 2 to operate.
Based on the measurement result of a, the presence or absence of the actual current flowing through the motor M is determined.

Here, when the relay 3 is off as instructed, no current is supplied to the motor M, so no current is detected in step ST4. In this case, the relay 3 is considered normal. After that, the relay 3 is switched on, the motor is energized based on the current command value according to the pedaling force of the pedal of the bicycle with auxiliary power, and power is supplied.

On the other hand, when the relay 3 is welded and turned on, a current flows through the motor M.
The current is detected at T4. In this case, the relay 3 is considered to be abnormal, and the processing of the controller 2 proceeds to step ST.
Go to 5. In step ST5, the energization of the motor M is stopped, and in step ST6, the warning lamp 5 is turned on, and the warning buzzer 6 generates a warning sound to notify the operator. The warning light 5 and the warning buzzer 6 are
Only one of them may be provided.

As described above, according to this embodiment, the state of the relay 3 can be inspected each time before the bicycle with auxiliary power is operated, so that the relay 3 is a safety device when a short circuit occurs during operation. It is possible to avoid malfunction or damage of the device due to non-functioning as.

In the present embodiment, the power supply to the motor M is stopped in step ST5, but this may be omitted and the process may proceed to step ST6. In this case, although the system determines that the relay 3 has an abnormality, the motor M can be operated, and the relay 3 can be repaired or replaced while using it as the auxiliary power of the bicycle with the auxiliary power. You can move as much as you can. In this case, of course, it is desirable for the user to promptly repair or replace the relay 3.

(2) Second Embodiment A. Configuration of Embodiment Next, FIG. 3 is a block diagram showing the configuration of a control circuit including a failure detection device for switch means according to a second embodiment of the present invention. The failure detecting device for the switch means is applied to an electric wheelchair (not shown). In the figure, reference numeral 31 is an occupant operation panel, 32 is a power source such as a storage battery, 33 and 34 are motors for rotating left and right wheels, and 3
Reference numerals 5 and 36 denote motor control units that drive the rotation of the motors 33 and 34.

Each of the motors 33, 34 is provided with a vehicle speed sensor 33a, 34a for detecting their rotational speed. Further, relays 37, 38 are inserted in the energization paths between the motors 33, 34 and the motor control units 35, 36 as safety devices for shutting off the overcurrent. An electric current is supplied to 34. That is, the relay 3 is in the ON state during the normal energization, but is turned off in the event of an abnormality such as a short circuit to prevent an overcurrent from flowing to the motors 33 and 34. In the state shown, the relays 37, 3
8 is off. Between the common terminals of the relays 37 and 38 and the motors 33 and 34, current detectors 33b and 34b are provided.
Is inserted, and the current detectors 33b and 34b output a current detection signal according to the current flowing between them.

Reference numeral 39 is a warning light composed of an LED, 40 is a warning buzzer, and these warning lights 39 and the warning buzzer 4 are provided.
0 is provided to notify an occupant that an abnormality such as welding of the movable contacts of the relays 37 and 38 has occurred. Reference numeral 11 indicates a controller, and the controller 11 is configured by hardware such as a CPU (central processing unit) 12 and a memory.

The operation panel 31 has a main switch 31a for opening and closing a circuit for supplying a current to the controller 11.
Is provided. In addition, the operation panel 31 is provided with a joystick (speed control operator) 31b for forward / backward operation of each wheel and speed control. When the occupant tilts the joystick 31b, the joystick 31b outputs a voltage according to the tilt angle.

The CPU 12 has an input interface 27.
Various signal outputs and switch outputs are fetched from a to 27d and 27g, and the CPU 12 outputs control signals such as various command values to the outside from the output interfaces 27e and 27f. The CPU 12 operates based on a predetermined program and performs various functions. In the figure, the blocks are displayed on the assumption that the joystick input unit 13, the command vehicle speed calculation unit 14, etc. are provided for each of these functions, and the function of each block will be described below. The functions of the CPU 12 may be performed by hardware.

The voltage output from the joystick 31b is A / D by the input interface 27a.
It is converted and input to the joystick input unit 13. The joystick input unit 13 outputs a tilt angle signal based on the digitally converted voltage value. In this way, the tilt angle signal takes a value according to the tilt angle of the joystick 31b. The tilt angle signal has a front-rear direction component and a left-right direction component. For example, the joystick 3
When 1b is tilted forward, the front-back direction component is a positive value,
When tilted backward, the front-back direction component has a negative value.

The command vehicle speed calculation unit 14 calculates the speed at which each wheel should be rotated based on the tilt angle signal from the joystick input unit 13, and outputs a separate command vehicle speed signal for each of the left and right wheels. The PWM wave calculation unit 15 outputs a PWM wave serving as a control signal based on the command vehicle speed signal for each of the left and right wheels to control the left and right motor control units 35 and 36.
As a result, the motor 3 is controlled by the motor control units 35 and 36.
The amount of electricity supplied to the motors 3, 34 is controlled, and the motors 33, 34 are controlled.
Rotation speed, that is, the speed of each wheel is controlled. The vehicle speed calculator 16 receives the vehicle speed detection signals input from the vehicle speed sensors 33a and 34a, calculates the actual speeds of the left and right wheels, and outputs the actual vehicle speed signal. PWM wave calculator 15
Takes in the actual vehicle speed signal and
Feedback control of 5, 36 is performed.

The current detection signals from the current detectors 33b and 34b are A / D converted by the input interface 27g, and the converted digital signal is taken into the current calculator 19. Then, the current calculation unit 19 calculates, based on this,
The actual current value flowing in the left and right motors 33, 34 is calculated, and the actual current signal is output. The relay abnormality determination unit 20 determines, based on the actual current signal from the current calculation unit 19, whether or not an abnormality such as welding of movable contacts of one or both relays 37 and 38 has occurred. When it is determined that one of the relays 37 and 38 has an abnormality, the relay abnormality determination unit 20 outputs an ON signal to the LED lighting control unit 21 and the buzzer control unit 22 to notify the passenger.

LED lighting controller 21 and buzzer controller 2
2 turns on the warning lamp 39 and causes the warning buzzer 40 to generate a warning sound in response to the ON signal from the relay abnormality determination unit 20, respectively. Further, the timer 23 outputs a signal corresponding to time, and the time counting section 24 outputs an elapsed time signal based on this signal. This elapsed time signal is input to the relay abnormality determination unit 20, and the relay 3
It is used to judge whether there are 7, 38 abnormalities.

As will be described later, such a relay 3
The abnormality judgment of Nos. 7 and 38 is performed only for a predetermined time, and within this predetermined time, the relay abnormality judgment unit 20
Outputs an OFF instruction signal to the relays 37 and 38, and outputs an abnormality instruction energization instruction signal to the PWM wave calculation unit 15. At this time, even if the command vehicle speed signal from the command vehicle speed calculation unit 14 is output, the PWM wave calculation unit 15 does not accept this, and therefore the wheels are not driven.

B. Operation of Embodiment B-1. Normal Control Operation Next, the normal control operation of this embodiment will be collectively described as follows. First, the occupant has a joystick 3.
When 1b is tilted, a tilt angle signal is output from the joystick input unit 13 according to the tilt angle, and this tilt angle signal is input to the command vehicle speed calculation unit 14. Based on this tilt angle signal, the command vehicle speed calculation unit 14 calculates the command vehicle speed for the left wheel and the command vehicle speed for the right wheel, and outputs a command vehicle speed signal corresponding thereto. Based on this command vehicle speed signal, the PWM wave calculation unit 15 causes the left and right motor control units 3 to
Control 5, 36. As a result, each motor control unit 3
The amount of electricity supplied to the motors 33 and 34 from the motors 5 and 36 is controlled, and the rotation speed of the motors 33 and 34, that is, the speed of each wheel is controlled. With this control, if the wheels rotate at equal speeds, the electric wheelchair goes straight (including forward and reverse), and if the left and right wheels rotate at different speeds, the direction of travel of the electric wheelchair changes. It

When the wheels are actually driven, the vehicle speed calculator 16 calculates the actual vehicle speed of the left wheel and the actual vehicle speed of the right wheel, and outputs an actual vehicle speed signal corresponding to them. These actual vehicle speed signals are input to the PWM wave calculation unit 15. The PWM wave calculation unit 15 matches the actual vehicle speed of the left wheel with the command vehicle speed to the left wheel, and
The motor control units 35 and 36 are adjusted so that the actual vehicle speed of the right wheel and the command vehicle speed to the right wheel match. As a result, the electric wheelchair advances in a desired direction at a speed desired by the occupant.

B-2. Relay Failure Inspection Operation Next, FIG. 4 is a flowchart showing an example of relay failure detection operation in this embodiment. Referring to the figure,
The relay failure detection operation will be described. In the following description, for the sake of simplification, this relay failure detection operation is assumed to detect the failure of the relay 37 for the left wheel, but the same operation is also performed for the relay 38 for the right wheel. . The failure detecting operation of the left relay 37 and the failure detecting operation of the right relay 38 may be performed at the same time, or the other may be performed after completion of one.

First, the occupant operates the operation panel 31 to turn on the main switch 31a. As a result, current is supplied to the controller 11 to enable operation, and
The motor control units 35 and 36 are in the standby state and the system is in the activated state.

Then, the relay abnormality judging section 20 outputs a relay off signal to turn off the relay 37 (step ST7). As a result, the relay 37 should be in the OFF state shown in the drawing unless the movable contact of the relay 37 is welded to the ON-side terminal. Next, after outputting the relay off signal, the relay abnormality determination unit 20 waits for a set predetermined time, and outputs an energization instruction signal to the motor 33, which is an inspection command value (steps ST8, ST).
9). As a result, the PWM wave calculation unit 15 operates and tries to flow a drive current of a predetermined energization amount from the motor control unit 35. In this case, as instructed in step ST7,
When the relay 37 is in the off state, this drive current is not given to the motor 33.

After that, the system waits for a set predetermined time (step ST10), and the actual current flowing through the motor 33 is read by the relay abnormality judging part 20 through the current detector 33b and the current calculating part 19 (step ST11). Then, this actual current is compared with the set value (step ST1
2) If it is equal to or more than the set value, the determination result is “YES”, and the process proceeds to step ST13. The set value here is an extremely weak current value. As described above, when the relay 37 is in the off state, the drive current is not applied to the motor 33, and for example, when the electric wheelchair is about to stop on the slope and the current generated by the motor 33 itself by the dynamic braking is equal to or more than the current. No current is detected by the current detector 33b. Therefore, the determination result of step ST12 being "YES" means that the relay 37 has an abnormality.

In step ST13, the relay abnormality determination section 20 outputs an ON signal to the LED lighting control section 21 and the buzzer control section 22. As a result, the warning light 39 is turned on and the warning buzzer 40 emits a warning sound. In this way, the passenger is notified that the relay 37 is abnormal.

Next, in step ST14, the above-mentioned normal control operation is performed. In this normal control operation, first, the output of the energization instruction signal from the relay abnormality determination unit 20 is stopped, so that the PWM wave calculation unit 15 is activated by the command vehicle speed signal from the command vehicle speed calculation unit 14. . In the normal control operation, the joystick 31
When b is tilted, the command vehicle speed signal from the command vehicle speed calculation unit 14 is taken into the relay abnormality determination unit 20, and the relay abnormality determination unit 20 outputs the ON command signal to turn on the relay 37. When the occupant sets the joystick 31b to the neutral position, the command vehicle speed signal corresponding to the command vehicle speed "0" is input from the command vehicle speed calculation unit 14 to the relay abnormality determination unit 20, and the relay abnormality determination unit 20 is turned off accordingly. Output a command signal, turn off the relay 37, and set the traveling speed to 0.
To

In this way, the user can operate the electric wheelchair by operating the joystick 31b. Here, although the system determines that the relay 37 is abnormal as described above, the normal control operation is performed to enable the operation without performing the process of stopping the traveling of the wheels. This is because even if the relay 37 is in an abnormal state, that is, the relay 37 remains on, there is no substantial obstacle to the traveling of the electric wheelchair itself. That is, when the occupant tilts the joystick 31b, the motor 33 is correspondingly tilted.
Rotates, and when the joystick 31b is set to the neutral position, the motor 33 stops. Therefore, as an occupant, the electric wheelchair can be driven as it is and moved to a place where the relay 37 can be repaired or replaced.

However, in this case, since the relay 37, which is a safety device for the motor 33, does not function, in the unlikely event that
When an abnormality such as a short circuit occurs, it is inevitable that an overcurrent flows through the motor 33. Therefore, in order to avoid a failure of the motor 33, the relay abnormality determination unit 20 may output a command vehicle speed signal of vehicle speed "0" to stop the rotation of the motor 33 after displaying the abnormality in step ST13. .

In step ST12, if the actual current flowing through the motor 33 is less than the set value, the determination result is "NO". This indicates that there is no abnormality in the relay 37, and thereafter, the step ST1 is performed as it is.
Proceeding to step 4, normal control operation is performed.

After that, the process proceeds to step ST15, where it is determined whether or not the main switch 31a is turned off. If the main switch 31a is turned off, the current supplied to the controller 11 is shut off and the system does not operate. It becomes a state. That is, when the passenger wants to park the electric wheelchair, the main switch 31a is turned off. On the other hand, if the main switch 31a is not turned off in step ST15, the process returns to step ST14 and the traveling of the electric wheelchair is continued.

C. Effects of the Embodiment In this embodiment, after the relays 37 and 38 are incorporated in the electric wheelchair, it is possible to determine an abnormality such as welding of the relays 37 and 38. Moreover, the abnormality of the relay 37 can be detected at a predetermined time while the electric wheelchair is running, and accordingly, the occupant is notified or the electric wheelchair is stopped. After that, by repairing and replacing the relays 37 and 38, it is possible to prevent the motors 33 and 34 from being adversely affected.

Further, in this embodiment, the relay abnormality determination unit 20 first outputs the OFF instruction signal to the relays 37 and 38, and after a predetermined time has elapsed, calculates the PWM test of the conduction instruction signal for abnormality inspection. Output to the unit 15 (steps ST7 to ST9). Since the relays 37 and 38 have mechanical movable contacts, the movable contacts vibrate even after the OFF command signal is input to the relays 37 and 38, so that the relays 37 and 38 are immediately in the non-conductive state. do not become. However, as in this embodiment, after the elapse of a predetermined time from the output of the OFF command signal, the PWM wave calculation unit 15 and the motor control unit 3
By trying to energize the motors 33, 34 through 5, 36, a reliable abnormality determination can be made.

Further, immediately after the main switch 31a is turned on, that is, immediately after the electric wheelchair is activated, step S
In the normal control operation at T14, the OFF instruction is given to the relays 37 and 38 until the ON instruction is given to the relays 37 and 38, and the relay abnormality determination unit 20 outputs the energization instruction signal. As described above, in this embodiment, immediately after the system is activated and before the traveling control of the electric wheelchair is performed,
The energization instruction signal which is an inspection signal is output to the relay 37,
38 abnormalities can be determined.

Further, in this embodiment, the relay abnormality judging section 20 outputs the energization instruction signal for a predetermined short time, specifically, for several tens of milliseconds. This is because when the motors 33 and 34 are stopped, the motors 33 and 3 are
Even if a current flows through 4, it does not start immediately because of inertia, but if there is an abnormality in the relays 37, 38, if a certain period of time elapses, the energization instruction signal, which is a signal for inspection, Therefore, the motors 33 and 34 start rotating, which may cause the electric wheelchair to run. In this embodiment, the output of the energization instruction signal is expressed in several tens.
By setting the time only for milliseconds, the abnormality of the relays 37, 38 can be detected before the electric wheelchair starts traveling.

D. Modification Example of Relay Failure Detection Operation Next, FIG. 5 is a flowchart showing a modification example of the relay failure detection operation in the second embodiment. In the following explanation, for simplification, this relay failure detection operation is
Although the failure of the left wheel relay 37 is detected, the same operation is performed for the right wheel relay 38. The failure detecting operation of the left relay 37 and the failure detecting operation of the right relay 38 may be performed at the same time, or the other may be performed after completion of one.

In this modified example, the relay abnormality determination section 20 outputs an energization instruction signal for energizing the motor 33 in the direction of normal rotation and energization in the direction of reverse rotation of the motor 33, thereby energizing the motor 33 for normal rotation. The relay abnormality determination unit 20 determines that the relay 37 is abnormal for the first time when the actual current flowing through the motor 33 is detected by both the instruction and the reverse rotation energization instruction.

First, the occupant operates the operation panel 31 to turn on the main switch 31a, and the system is activated as described above. Then, the relay abnormality determination unit 20 outputs a relay off signal to turn off the relay 37 (step ST16). This makes relay 3
As long as there is no abnormality such as the movable contact of No. 7 being welded to the on-side terminal, the relay 37 should be in the off state shown in the figure. Next, after outputting the relay-off signal, the relay abnormality determination unit 20 waits for the set predetermined time and the motor 33
An energization instruction signal for rotating the vehicle in the forward direction is output (steps ST17 and ST18).

After that, the system waits for a preset time (step ST19), and the actual current flowing through the motor 33 is read by the relay abnormality judging part 20 through the current detector 33b and the current calculating part 19 (step ST20). Then, this actual current is compared with the set value (step ST2
1) If it is equal to or more than the set value, the determination result is “YES”, and the process proceeds to step ST22. The set value here is an extremely weak current value. As described above, when the relay 37 is in the off state, the drive current is not given to the motor 33, but the electric wheelchair is about to stop on the slope,
Since the motor 33 itself generated power by dynamic braking,
A certain amount of current may be detected by the current detector 33b, and it may be erroneously determined that the contact of the relay 37 is welded. Therefore, in this case, the operation proceeds to the subsequent step ST22 and subsequent steps.

In step ST22, the relay abnormality determination section 20 outputs to the motor 33 an energization instruction signal for rotating the vehicle in the backward direction. After that, it waits for a set predetermined time (step ST23), and the current detector 33b,
The actual current flowing through the motor 33 is read by the relay abnormality determination unit 20 through the current calculation unit 19 (step ST2).
4). Then, this actual current is compared with the set value (step ST25), and if it is equal to or larger than the set value, the judgment result is "YE
S ”, and the process proceeds to step ST26. The set value here is an extremely weak current value.

As described above, the determination result of step ST25 being "YES" means that the actual current above the predetermined level is detected by both the forward rotation energization instruction and the reverse rotation energization instruction of the motor 33. Therefore, it is unlikely that the motor 33 itself is performing dynamic braking when the electric wheelchair is about to stop on the slope. That is, there is an abnormality in the relay 37.

Therefore, in step ST26, the relay abnormality determination section 20 outputs an ON signal to the LED lighting control section 21 and the buzzer control section 22. As a result, the warning light 39
Lights up and the warning buzzer 40 emits a warning sound. In this way, the passenger is notified that the relay 37 is abnormal.

Next, in step ST27, the above-mentioned normal control operation is performed. Here, first, the output of the energization instruction signal of the relay abnormality determination unit 20 is stopped, so that the PWM wave calculation unit 15 is operated by the command vehicle speed signal from the command vehicle speed calculation unit 14. That is, the relay abnormality determination unit 20 outputs the energization instruction signal for a predetermined short time, specifically, for several tens of milliseconds. The relay abnormality determination unit 20 also outputs an ON command signal to turn ON the relay 37. This allows the user to operate the joystick 31b to drive the electric wheelchair. In order to avoid the failure of the motor 33, after displaying the abnormality in step ST26, the motor 3
In order to stop the rotation of No. 3, the relay abnormality determination unit 20 may output the command vehicle speed signal of the vehicle speed "0", as described above.

In step ST21 or step ST25, the actual current flowing through the motor 33 is
If it is less than the set value, the determination result is “NO”. This indicates that there is no abnormality in the relay 37. After that, the process directly proceeds to step ST27 and the normal control operation is performed.

After that, the process proceeds to step ST28, where it is determined whether or not the main switch 31a is turned off. If the main switch 31a is turned off, the current supplied to the controller 11 is shut off and the system does not operate. It becomes a state. That is, when the passenger wants to park the electric wheelchair, the main switch 31a is turned off. On the other hand, if the main switch 31a is not turned off in step ST28, the process returns to step ST27 and the traveling of the electric wheelchair is continued.

In this example, the following effect can be achieved in addition to the same effect as the second embodiment.
That is, in the case of a vehicle such as an electric wheelchair capable of moving forward and backward, real current may be generated in the motors 33 and 34 due to the dynamic braking when the vehicle is climbing or descending, or when the vehicle stops on a slope. On the other hand, in the present embodiment, the motors 33, 34
To the motors 33, 34 by giving an energization instruction for causing one rotation and another energization instruction for causing the other rotation.
By determining the actual current flowing through the relay, it is possible to improve the accuracy of the abnormality determination of the relays 37 and 38. Note that, contrary to the above example, it is possible to output the energization instruction signal for rotating the motor 33 in the backward direction first and then output the energization instruction signal for the direction of rotating the motor 33 in the forward direction.

In the above embodiment, the present invention is applied to a motor drive circuit for a bicycle with auxiliary power or a motor drive circuit for an electric wheelchair, but the present invention is not limited to this.
It can also be applied to motor drive circuits of other devices. Further, the present invention can be applied not only to inspect the abnormality of the relay but also to inspect the abnormality of other switch means such as the switch using the semiconductor element.

[0063]

As described above, according to the present invention, even if an abnormality of the switch means such as welding of a relay occurs after the switch means is incorporated in the motor drive device, it is possible to judge whether or not this abnormality exists. It is possible to Further, according to the invention described in claim 1, since it is possible to know the abnormality of the switch means such as the welding of the relay before the operation of the motor drive device, it is possible to switch when the overcurrent occurs due to a short circuit after the operation. It is possible to prevent malfunction or damage of the device due to non-function of the device. According to the second aspect of the invention, the abnormality determination is performed when the switch unit is instructed to turn off and the motor is not driven. After that, by repairing or replacing the relay, it is possible to prevent the motor from being adversely affected.
According to the invention of claim 3, the switch means has a mechanical movable contact such as a relay by instructing energization by the energization instructing means after a predetermined time has elapsed from the OFF command, and vibration of Therefore, even when the non-conduction state is not immediately established, a reliable abnormality determination can be made. According to the invention described in claim 4, it is possible to judge the abnormality of the switch means before the operation of the motor drive device. According to the invention described in claim 5, it is possible to determine the abnormality of the switch means before the rotation of the motor is started. According to the invention described in claim 6, even if a current flows through the motor itself due to self-power generation during dynamic braking of the motor, it is not possible to erroneously determine that the current is abnormal. The accuracy of the abnormality determination can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the same embodiment.

FIG. 3 is a block diagram showing a configuration of a control circuit including a second embodiment of the present invention.

FIG. 4 is a flowchart showing an example of a relay failure detection operation in the same embodiment.

FIG. 5 is a flowchart showing another example of the relay failure detection operation in the embodiment.

[Explanation of symbols]

1 motor drive section (energization means), 2 controller, 2
a current detection unit (current detection unit), 2b relay abnormality determination unit (abnormality determination unit, abnormality processing unit), 2c relay O
N / OFF command section (switch control means), 2d Current command calculation section (energization instruction means, abnormality processing means), 2e PW
M calculation section (energization instruction means), 3 relays (switch means), 4 current sensors (current detection means), 5 warning lights (abnormality processing means), 6 warning buzzers (abnormality processing means),
E secondary battery, 11 controller, 12 CPU, 1
3 Joystick input part, 14 Command vehicle speed calculation part,
15 PWM wave calculation unit (energization instruction unit), 16 vehicle speed calculation unit, 19 current calculation unit, 20 relay abnormality determination unit (switch control unit, abnormality determination unit, abnormality processing unit), 21L
ED lighting control unit (abnormality processing unit), 22 buzzer control unit (abnormality processing unit), 23 timer, 24 time counting unit, 31 operation panel, 31a main switch, 3
1b Joystick, 32 power supply, 33, 34 motor, 33a, 34a vehicle speed sensor, 33b, 34b
Current detector (current detecting means), 35, 36 Motor control section (energizing means), 37, 38 Relay (switch means), 39 warning light (abnormality processing means), 40 warning buzzer (abnormality processing means)

Front Page Continuation (72) Inventor Yoshiaki Ezaki 2500 Shinkai, Iwata, Shizuoka Prefecture Yamaha Motor Co., Ltd.

Claims (6)

[Claims] 1. A current-carrying means for supplying a current corresponding to a given command value to a motor, and a current-carrying path connecting the current-carrying means and the motor, and being electrically conductive / non-conductive in response to an on / off command. A failure detection device for a switch means applied to a motor drive device comprising a switch means for switching to any state, wherein a predetermined inspection command value is supplied to the energizing means before the motor drive device is operated. An energization instruction means for instructing energization, a switch control means for issuing an off command to the switch means while energization is instructed by the energization instruction means, a current detection means for detecting a current flowing through the motor, When a current is detected by the current detection means while the power supply is instructed by the power supply instructing means and the switch control means issues an off command, The switch means is provided with an abnormality determining means for determining that the abnormality is present, and when the abnormality determining means determines an abnormality, an abnormality processing means for stopping the energization of the motor and notifying the abnormality. A failure detection device for switch means, characterized in that 2. An energizing means for supplying a current corresponding to a given command value to a motor, and an energizing path connecting the energizing means and the motor for conducting / non-conducting in response to an on / off command. A failure detection device for a switch means applied to a motor drive device comprising a switch means for switching to any state, wherein a predetermined inspection command value is given when an OFF command is issued to the switch means. Is supplied to the energizing means to instruct energization, a current detecting means for detecting a current flowing through the motor, and a current is detected by the current detecting means while an energizing instruction is given by the energizing instructing means. A failure detecting device for the switch means, wherein the switch means has an abnormality determining means for determining that the switch means is abnormal. 3. The energization instruction by the energization instruction means is
3. The failure detection device for switch means according to claim 2, wherein the failure detection device is performed after a predetermined time has elapsed from the off command to the switch means and before the on command to the switch means. 4. An off command is given to the switch means immediately after the motor drive device is activated, and the energization instruction by the energization instruction means is issued after the motor drive device is activated.
The failure detection device for the switch means according to claim 2 or 3, which is performed before an ON command to the switch means. 5. The energization instruction by the energization instruction means is
5. The method according to claim 2, wherein the operation is performed for a predetermined time.
5. A failure detection device for switch means according to any one of 1. 6. The energization instruction by the energization instruction means is
It includes an energization instruction for rotating the motor in one direction and an energization instruction for rotating the motor in the other direction. Both of the energizing instructions to rotate it,
The failure detection device for switch means according to any one of claims 2 to 5, wherein the abnormality determination means determines that the switch means is abnormal when the actual current of the motor is detected.