JPH08172721A - Abnormality detection apparatus of motor output system - Google Patents

Abstract

PURPOSE: To obtain an abnormality detection apparatus which prevents the breakdown of a peripheral apparatus due to an overcurrent by a method wherein, when a state that the deviation of a current detection value with reference to a current instruction value is larger than a prescribed threshold value is continued for a definite period or longer, a current output system to a motor is judged to be abnormal and a power supply to the motor is stopped. CONSTITUTION: In an abnormality judgment part 2c, the deviation of a current detection value with reference to a current instruction value supplied from a current comparison part in a continuity state that a relay 3 has been turned on is compared with a threshold value, for abnormality detection, which has been stored in a judgment-value storage part 2d. Then, when the deviation is larger than the threshold value while a definite period which is clocked by a timer 2e elapses, the abnormality judgment part 2c regards an abnormality as have been occurred in the output system of a motor M, it outputs a power- supply-stop instruction to a current-instruction computation part 2f, and it outputs an OFF-instruction to the relay 3 so as to stop a power supply to the motor M. Thereby, it is possible to prevent the breakdown of a peripheral apparatus due to an overcurrent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for use in a current control circuit for controlling a current to be supplied to a motor mounted on an electric vehicle such as a carrier vehicle, an electric vehicle, and a manpowered vehicle with auxiliary power. A system abnormality detection device.

[0002]

2. Description of the Related Art Conventionally, electric vehicles such as a carrier vehicle, an electric vehicle, and a manpowered vehicle with an auxiliary power source are known in which electric current is supplied to a motor based on a power source such as a secondary battery to drive the motor to obtain power. ing. Generally, in this type of electric vehicle, the current actually supplied to the motor (hereinafter referred to as the actual current) is measured and the result is fed back to a control means such as a controller, and the actual current is fed by the control means. Current control is performed by performing a correction operation so as to match the command value.

[0003]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention By the way, there are problems such as a disconnection in a current path (hereinafter referred to as a motor output system) for guiding a current output from a power source to a motor, a contact failure due to a failure or deterioration of a circuit component including a relay. When it occurs, the current is not supplied to the motor at all, or the actual current becomes extremely small with respect to the current command value. In such a case, if the above-mentioned correction operation by the feedback control is performed, the current command value becomes extremely large, and on the contrary, an excessive current may be supplied into the circuit, which may damage peripheral devices. Also,
The same problem occurs because an overcurrent flows in the circuit even when a short circuit occurs in the motor output system. On the other hand, it is possible to judge such an abnormality of the motor output system by the magnitude of the deviation of the actual current from the current command value, and if it is judged to be abnormal, take measures such as stopping the energization, but it is a transient state. In the case of “1” or when noise or the like is mixed, the deviation may temporarily increase, so that it cannot always be concluded that the abnormality is as described above.

The present invention has been made in view of the above-mentioned circumstances, and accurately detects an abnormality in the motor output system without error,
It is an object of the present invention to provide a motor output system abnormality detection device capable of preventing peripheral devices from being damaged by overcurrent.

[0005]

In order to solve the above-mentioned problems, the invention according to claim 1 is to provide an energizing means for supplying a current corresponding to a given current command value to the motor, and an actual current flowing through the motor. A current detection unit that detects a current and outputs the magnitude of the current as a current detection value and the current command value and the current detection value are compared at any time, and the deviation of the current detection value from the current command value is output. And comparing the deviation with a predetermined threshold value at any time, and if the deviation is larger than the threshold value for a certain period or more,
An abnormality determination means for determining that the current output system to the motor is abnormal, and an abnormality processing means for stopping energization to the motor when the abnormality determination means determines an abnormality. There is.

Further, in the invention described in claim 2, in the invention described in claim 1, instead of the abnormality determining means, the deviation is accumulated at any time in a predetermined cycle, and an accumulated value in a predetermined period is predetermined. When it is larger than the threshold value, it is characterized by including abnormality determining means for determining that the current output system to the motor is abnormal.

The invention according to claim 3 is, in the invention according to claim 1 or claim 2, when the abnormality judging means judges that the abnormality has occurred, a notifying means for notifying the operator of the occurrence of the abnormality. It is characterized by having.

[0008]

According to the first aspect of the present invention, when the deviation of the actual current from the current command value exceeds the predetermined threshold value continues for a certain period or longer, it is determined that the motor output system is abnormal, and the motor output system is abnormal. It is possible to stop the energization of. As a result, the motor output can be accurately output without erroneously determining the abnormal status when the deviation of the actual current is delayed in the transient state with respect to the current command value or when noise is mixed in. It is possible to detect abnormalities such as disconnection, poor contact, and short circuit in the system, and prevent damage to peripheral devices due to overcurrent supply.

According to the second aspect of the invention, when the value obtained by accumulating the deviation of the actual current from the current command value for a certain period becomes larger than a predetermined threshold value, it is determined that the motor output system is abnormal. However, the power supply to the motor can be stopped. As a result, the same effect as that of the first aspect of the invention can be achieved.

According to the third aspect of the invention, in addition to the effect of the first or second aspect of the invention, the operator can immediately know that an abnormality has occurred.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a motor output system abnormality detection apparatus according to an embodiment of the present invention. This motor output system abnormality detection device is applied to, for example, a bicycle with auxiliary power (not shown). In a bicycle with auxiliary power, a current that is almost proportional to the pedal effort is supplied from the secondary battery to the motor, and the bicycle is driven by the 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 drives the motor M. This motor drive unit 1 is based on the discharge current supplied from the secondary battery E and is provided with a PWM (Pulse) which is given from a controller 2 (described later) as a current command.
The current corresponding to the duty ratio of the (Width Modulation) wave is supplied to the motor M.

Reference numeral 3 is a relay provided as a safety device when an abnormality occurs, and is inserted in a current path from the motor drive unit 1 to the motor M. This relay 3 is the controller 2
ON / OFF is controlled by. That is, the controller 2 turns on the relay 3 to supply the discharge current of the battery E to the motor M during normal energization, but turns off the relay 3 to stop the energization of the motor M when an abnormality is detected. Let

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 a CPU, a memory, a display section including an LED (Light Emitted Diode), etc., not shown, and hardware such as input interfaces 21 and 22, and the software configuration thereof is a current detection section. 2a, a current comparison unit 2b, an abnormality determination unit 2c, a determination value storage unit 2d, a software timer 2e, a current command calculation unit 2f, a PWM wave generation unit 2g, and a pedaling force calculation unit 2h.

The current detecting section 2a has an input interface 2
The current detection value that has been A / D (analog / digital) converted via 1 is measured, and the measurement result is output to the current comparison unit 2b. The current comparison unit 2b is a current command calculation unit 2 described later.
The current command value calculated by f is compared with the current detection value supplied from the current detection unit 2a, and the difference between these values (hereinafter referred to as deviation) is output.

The abnormality determining section 2c supplies an energization command corresponding to the pedaling force of the pedal of the bicycle with auxiliary power to the current command calculating section 2f.
Output to. Further, the abnormality determining unit 2c, in the conductive state in which the relay 3 is turned on, the deviation supplied from the current comparing unit 2b and the predetermined determination value (threshold for abnormality detection) stored in the determination value storage unit 2d. Value)). And
While a certain period of time measured by the timer 2e elapses,
When the deviation is always larger than the judgment value, the abnormality judging section 2c
Considers that an abnormality has occurred in the motor output system, outputs an energization stop command to the current command calculation unit 2f, and also relay 3
To turn off. Further, at this time, the fact that there is an abnormality is displayed on the display unit (not shown).

The pedaling force calculation unit 2h detects a voltage corresponding to the pedaling force of the pedal and outputs the pedaling force value as an energization command to the current command calculation unit 2f. The current command calculation unit 2f calculates a current command value corresponding to the energization command (including the energization stop command) supplied from the pedaling force calculation unit 2h and the abnormality determination unit 2c. P
The WM wave generation unit 2g generates a PWM wave having a duty ratio corresponding to the current command value supplied from the current command calculation unit 2f, and drives the motor drive unit 1 by this PWM wave.

Next, the operation of this embodiment will be described. FIG. 2 is a flowchart showing the operation of the controller 2 during operation of the bicycle with auxiliary power. In the following, the description will proceed along each step of this flowchart.

First, when the device is powered on, the controller 2 advances the processing to step ST1. Step S
At T1, the pedal effort calculation unit 2h detects a voltage corresponding to the pedal effort of the pedal and outputs the pedal effort value as an energization instruction to the current instruction calculation unit 2f. The current command calculator 2f calculates a current command value corresponding to this energization command and outputs the result to the PWM wave generator 2g.

Next, when proceeding to step ST2, the PWM wave generator 2g generates a PWM wave having a duty ratio corresponding to the current command value supplied from the current command calculator 2f, and drives the motor by the PWM wave. Move Part 1. As a result, the current corresponding to the duty ratio of the PWM wave is discharged from the battery E and supplied to the motor M. Since the relay 3 is a normally closed contact, it is in a conducting state at this time, and the motor M is energized.

Next, in step ST3, the current detector 2a measures the actual current detected by the current sensor 4 and outputs the measurement result to the current comparator 2b. When the process further proceeds to step ST4, the current comparison unit 2b obtains the difference (deviation) between the current command value calculated by the current command calculation unit 2f and the current detection value supplied from the current detection unit 2a. Then, the abnormality determination unit 2c determines whether or not the deviation is larger than the determination value stored in the determination value storage unit 2d.

If the deviation of the actual current from the current command value is larger than the judgment value, the judgment result of step ST4 becomes "Yes", and the process proceeds to step ST5. Step S
At T5, the timer 2e starts measuring a certain period of time.

When the state in which the deviation becomes larger than the determination value continues for a certain period or more, the determination result of step ST6 becomes "Yes", and the process proceeds to step ST7.
In step ST7, the abnormality determination unit 2c determines that an abnormality has occurred in the motor output system, and outputs an energization stop command to the current command calculation unit 2f. As a result, the current command value calculated by the current command calculator 2f becomes "0", and the output of the PWM wave is stopped.

Further, in step ST7, the abnormality judging section 2c issues an OFF instruction to the relay 3. As a result, the relay 3 is turned off. Here, even if the relay 3 fails and is not turned off, the current command value is "0", so the energization of the motor M is stopped. Further, the abnormality determination unit 2c displays the fact that an abnormality has occurred on a display unit (not shown) to notify the operator.

On the other hand, when the difference between the actual current and the current command value is smaller than the judgment value, or when the difference between the actual current value and the current command value is temporarily large and does not continue for a certain period or longer, the above-mentioned step ST4 is performed.
The result of the determination is “No”. In this case, the process proceeds to step ST10 without proceeding to steps ST7 and ST8, and the count value of the timer 2e is cleared.

In this way, the above-mentioned operation is repeated while the apparatus is powered on, and when the power is turned off, the judgment result of step ST9 becomes "Yes", and the above-mentioned operation is completed.

As described above, according to this embodiment, when the state where the deviation between the current command value and the actual current becomes larger than the judgment value continues for a certain period or longer, it is judged that the motor output system is abnormal and the motor output system is abnormal. The energization can be stopped. As a result, the state in which the deviation increases temporarily, such as when the rise of the actual current is delayed with respect to the current command value in the transient state or when noise is mixed, is not accurately determined as abnormal, and the motor output system accurately It is possible to detect abnormalities such as disconnection, poor contact, and short circuit, and prevent damage to peripheral devices and the like due to supply of overcurrent.

The present invention is not limited to the mode in which an abnormality is determined when the state in which the deviation between the current command value and the actual current is larger than the determination value continues for a certain period or more, as in the above-described embodiment. For example, the above deviation may be accumulated at any time in a predetermined cycle, and if the accumulated value for a certain period is larger than a predetermined threshold value, it may be determined to be abnormal. Even in such a case, it is possible to make an accurate abnormality determination excluding the transient state and the mixing of noise.

The above-described embodiment is an application of the present invention to a motor output system of a bicycle with auxiliary power.
The present invention is not limited to this, and can be applied to motor output systems of other devices.

[0031]

As described above, according to the present invention, an abnormality such as a disconnection in a motor output system, a contact failure due to a failure or deterioration of components in a circuit, a short circuit, etc. can be accurately detected without error, and an overcurrent is supplied. It is possible to prevent the destruction of peripheral devices due to.

[Brief description of drawings]

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

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Motor drive part (energization means), 2 ... Controller, 2a ... Current detection part (current detection means), 2b ... Current comparison part (current comparison means), 2c ... Abnormality judgment part (abnormality judgment means) , Abnormality processing means, notification means), 2d ... Judgment value storage section (abnormality determination means), 2e ... Software timer (abnormality determination means), 2f ... Current command calculation section, 2g ... PWM wave generation section (energization) Means), 2h ... treading force calculation part, 3 ... relay (abnormality processing means), 4 ... current sensor (current detection means), E ... secondary battery.

Claims (3)

[Claims] 1. An energizing means for supplying a current corresponding to a given current command value to a motor, and a current detecting means for detecting an actual current flowing through the motor and outputting the magnitude of the current as a current detection value. The current command value and the current detection value are compared at any time, and a current comparison unit that outputs a deviation of the current detection value from the current command value is compared with the deviation and a predetermined threshold value at any time to obtain the deviation. Is greater than the threshold for a certain period of time,
An abnormality determination means for determining that the current output system to the motor is abnormal, and an abnormality processing means for stopping energization to the motor when the abnormality determination means determines an abnormality. Motor output system abnormality detection device. 2. In place of the abnormality determining means, the deviation is accumulated at any time in a predetermined cycle, and when the accumulated value in a certain period is larger than a predetermined threshold value, the current output system to the motor is abnormal. The abnormality detection device for a motor output system according to claim 1, further comprising abnormality determination means for determining that 3. The informing device according to claim 1, further comprising an informing unit for informing an operator of the occurrence of the abnormality when the abnormality determining unit determines that the abnormality is generated.
Abnormality detection device for the motor output system described.