JPH0767386A - Motor drive controller - Google Patents

Abstract

PURPOSE:To control a motor so that the motor continues to be driven when a motor drive voltage fluctuates and no excessive current flows when the motor is overloaded. CONSTITUTION:A voltage fluctuation detection circuit 26 is provided for outputting a low-level signal (prohibition signal) to a control circuit 20 by the amount of time corresponding to a fluctuation width when a motor drive voltage increases to a specific width or more by monitoring the fluctuation of the motor drive voltage. Therefore, when the motor drive voltage increases on normal operation when a motor 12 is not overloaded, the voltage fluctuation detection circuit 26 outputs a prohibition signal to the control circuit 20 by the amount of time corresponding to the fluctuation width, thus driving the motor 12 while the prohibition signal is input even if the output of a comparator 22 is high in the control circuit 20. On the other hand, when an overload occurs in the case of the increase in motor drive voltage less than a specific width, the control circuit 20 controls the motor 12 so that no overcurrent flows based on the output of the comparator 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor drive control device, and more particularly to a motor drive control device suitable for controlling a drive motor of a power window device.

[0002]

2. Description of the Related Art Conventionally, automobiles and the like equipped with a power window device that uses a motor as a drive source and moves up and down a door glass have been widely used. As this power window device, a device having a function of preventing foreign matter from being caught has recently been developed.

In this type of power window device, when a foreign object is caught between the door glass and the door frame when the door glass is raised, load fluctuation occurs, and the resulting overload condition of the motor causes the motor current. It is detected by the increase of the number of times, and measures such as stopping the rising of the door glass and reversing are taken.

Particularly in the auto switch, when the up or down side contact is turned on, the motor continues to be driven even if the hand is released and the door glass is moved until it is fully closed or fully opened. Therefore, the motor current is detected. It is effective to take the above measures.

Since the motor is overloaded and the motor current increases even when the door glass is fully closed, a fully closed detection sensor is provided in the vicinity of the fully closed door to distinguish between the foreign matter trapping and the fully closed.

[0006]

However, if the motor drive voltage fluctuates due to the voltage fluctuation of the battery as the power source or the driving / stopping of other on-board equipment, the motor current fluctuates in accordance with this driving voltage, and the motor overdrive The load may be erroneously detected. Normally, the motor current fluctuates depending on the load applied to the motor without depending on the driving voltage. However, when the driving voltage drastically fluctuates, the fluctuation causes a temporary change in the motor current.

For example, when the drive voltage increases, a current increase similar to the inrush current occurs according to the increase amount, which exceeds the threshold value for determining whether or not the current is abnormal, which causes an overload of the motor. There is a possibility that erroneous detection may occur, and therefore there is a possibility that the motor will stop and the door glass will stop midway, even if there is no foreign matter trapped during the raising and lowering of the door glass.

In a circuit for differentiating the motor current and detecting the motor overload state based on the rate of change of the motor current, the above-mentioned erroneous detection tends to occur particularly due to the fluctuation of the power supply voltage.

The present invention has been made in consideration of the above facts, and an object thereof is to continuously drive a motor without being affected by the fluctuation of the motor driving voltage and to overload the motor when the motor driving voltage fluctuates. An object of the present invention is to provide a motor drive control device capable of controlling a motor so that an overcurrent does not flow when a state occurs.

[0010]

A motor drive control device according to the present invention compares a voltage value corresponding to a motor current with a threshold value for overload detection to detect an overload state of a motor. Means for monitoring the fluctuation of the motor drive voltage and outputting a prohibition signal for a time period according to the fluctuation width when the motor drive voltage has fluctuated by a predetermined width or more, and when the prohibition signal is not output Has a control means for controlling the motor based on the output of the comparison means so that an overcurrent does not flow and for continuously driving the motor while the inhibition signal is output.

[0011]

According to the above construction, if the motor drive voltage fluctuates by a predetermined width or more for some reason during normal operation in which the motor is not overloaded, the motor drive voltage monitoring means prohibits for a time corresponding to the fluctuation width. Output a signal. Therefore, the control means continues to drive the motor while the prohibition signal is output. In this case, the control means continues to drive the motor as a result of the comparison means stopping the comparison itself between the voltage value corresponding to the motor current and the threshold value for overload detection while the inhibition signal is output. Alternatively, or the comparison means performs the comparison,
The control means may ignore the output of the comparison means and continue driving the motor. In this case, the time for which the prohibition signal is output changes according to the fluctuation range of the motor drive voltage, so it is long when the fluctuation range is large and short when the fluctuation range is small. On the other hand, when an overload condition occurs in the motor when the motor drive voltage does not fluctuate or fluctuates by less than a predetermined width, the control means controls the motor based on the output of the comparison means so that the overcurrent does not flow.

Therefore, when the motor is not overloaded, the motor will not stop due to fluctuations in the motor drive voltage.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a circuit configuration of a motor drive control device 10 according to this embodiment.

In FIG. 1, one end of the motor 12 is connected to one end of a relay switch 14, and the other end is grounded via a resistor R1. The other end of the relay switch 14 is connected to the power line 16 and therefore the relay switch 1
When 4 is turned on, the motor 12 is driven. The ON / OFF operation of the relay switch 14 is performed by controlling the excitation / non-excitation of the relay coil 18.

Both ends of the relay coil 18 are connected to a control circuit 20 as a control means. The power supply line 16 is also connected to the control circuit 20, and the relay coil 18 can be energized and de-energized.

The control circuit 20 is connected to the output terminal of a comparator 22 as a comparison means.
0 turns off the relay coil 18 when the comparator 22 outputs an overload detection signal which is a high level signal, and turns off the relay coil 18 when the comparator 22 outputs a low level signal. It is designed to be energized.

A branch line branched from between the motor 12 and the resistor R1 is connected to the positive input terminal of the comparator 22, and the voltage V1 when the motor current flows through the resistor R1 is input. It is like this.

A constant voltage power source from the control circuit 20 is connected to the negative input terminal of the comparator 22 via a resistor R2 and is also grounded via a resistor R3. As a result, a voltage V2 obtained by dividing the voltage of the constant voltage power source from the control circuit 20 by the resistors R2 and R3 is input as a threshold value (reference voltage) to the negative input terminal. ing.

The above constitutes a normal motor current detection circuit, in which a constant threshold value (voltage V2) is compared with the voltage V1 corresponding to the motor current, and when the voltage V1 exceeds the voltage V2, comparison is made. A high-level signal is output from the output terminal of the device 22, and the control circuit 20 deenergizes the relay coil 18 to interrupt (stop) the drive of the motor 12.

Further, in this embodiment, the branch line 24 which is grounded (in series connection) is connected to the power supply line 16 side of the motor 12 via the resistors R4 and R5, and the resistors R4 and R5 are connected.
Is connected to one end of the capacitor C1. The other end of the capacitor C1 is connected to the base of an NPN transistor Tr1 having a grounded emitter through a resistor R6. A resistor R7 is connected between the base and emitter of the transistor Tr1. Transistor Tr1
The collector of is connected to the control circuit 20.

That is, in the present embodiment, these resistors R4,
R5, R6, R7, capacitor C1, transistor Tr
1 as a motor drive voltage monitoring means for monitoring the variation of the motor drive voltage and outputting the prohibition signal (low level signal) to the control circuit 20 for a time corresponding to the variation width when the motor drive voltage increases by a predetermined width or more. The voltage fluctuation detection circuit 26 is configured.

Next, the operation and effect of this embodiment thus constructed will be described with reference to FIG.

When the relay coil 18 is excited by the control circuit 20, the relay switch 14 is turned on and the drive of the motor 12 is started. As shown by the range of arrow A in FIG. 2, the voltage V1 corresponding to the normal motor current is constant, but when the power supply voltage suddenly changes (increases), the motor current also resembles an inrush current. Causes an increase in current.
Therefore, the voltage V1 rapidly rises and exceeds the threshold value (see FIG. 2).

However, in the present embodiment, the rise of the power supply voltage raises the voltage V3 proportional to the motor drive voltage, a potential difference is generated across the capacitor C1, the charging of the capacitor is started, and the capacitor C1 causes the resistor R6. 2, a base current flows through the transistor Tr1 and the transistor Tr1 is turned on. As shown in FIG. 2, the inhibition signal, which is a low level signal, is supplied to the control circuit 20 for a certain period of time (constant until the charging of the capacitor is completed). Time) is output. In the control circuit 20, while the prohibition signal is being input, the relay coil 18 is kept in the energized state and the motor 12 is continuously driven regardless of the output of the comparator 22. That is, the output of the comparator 22 is ignored while the voltage fluctuation detection circuit 26 outputs the prohibition signal.

In this case, the time for which the inhibition signal is output is determined according to the fluctuation range of the motor drive voltage. This is because the time constant corresponding to the slope of the charging characteristic curve of the capacitor C1 is determined by the product of the capacitance of the capacitor C1 and the resistance value of the resistor R6, and when the fluctuation range of the motor drive voltage becomes large, the time constant is constant. This is because the time required for the capacitor C1 to reach full charge increases, and conversely, if the fluctuation range of the motor drive voltage is small, the time required for the capacitor C1 to reach full charge decreases accordingly.

Therefore, the time during which the transistor Tr1 which is determined according to the charging time of the capacitor C1 is maintained in the ON state, that is, the time when the inhibition signal is output changes according to the fluctuation range of the motor drive voltage, and when the fluctuation range is large. Is long and short when the fluctuation range is small. When the fluctuation range is less than the specified range,
Since the base current does not sufficiently flow and the transistor Tr1 remains off, the prohibition signal is not output.

On the other hand, if the motor 12 is overloaded when the motor drive voltage does not fluctuate during the operation of the motor 12 (including the fluctuation of less than the predetermined width), the prohibition signal is not output. Therefore, when the motor current exceeds the current value corresponding to the threshold value, the output of the comparator 22 becomes high,
In the control circuit 20, the relay coil 18 is brought into a non-energized state (non-excited state) so that an overcurrent does not flow in the motor 12.

It is also possible to mask the motor inrush current when the drive power is turned on (when the relay is first turned on) by making the voltage fluctuation detection circuit 26 in the above embodiment function from the start of driving.

Further, in the above embodiment, the case where the voltage fluctuation detection circuit for outputting the prohibition signal when the motor drive voltage is increased is provided as an example, but instead of this or together with this, FIGS. By providing the voltage fluctuation detection circuit as shown in (1), it is possible to output the prohibition signal which is a high level signal for a time period according to the reduction width when the motor drive voltage decreases.

The motor drive control device of the above embodiment is particularly suitable when applied to a power window device of a vehicle.
That is, in the power window device, when a foreign object is caught while the door glass is being raised by the driving force of the motor, the motor is overloaded and the motor current increases. Here, when the threshold value is exceeded, the drive of the motor is stopped or stopped after reversing for a predetermined time to prevent foreign matter from being damaged. In such a power window device, when other electric components (air conditioner, lamp, etc.) are activated and deactivated while the door glass is being raised and lowered, the motor drive voltage fluctuates. In the motor drive control device of the above embodiment, the voltage fluctuation detection circuit 26 outputs the prohibition signal only for the time corresponding to the fluctuation width, and the control circuit 20 continues to drive the motor 12 while the prohibition signal is output. Therefore, it is possible to solve the problem that the door glass stops while moving up and down due to the fluctuation of the motor drive voltage.

In the above embodiment, the case where the circuit for monitoring the fluctuation of the motor driving voltage is constructed by the analog circuit is illustrated, but the fluctuation of the motor driving voltage is monitored by software and only for the time corresponding to the fluctuation width. The control circuit 20 has a comparator 22.
The output of may be ignored.

Further, in the above embodiment, the voltage fluctuation detecting circuit 2
While the control circuit ignores the output of the comparator 22 and stops the determination while 6 outputs the prohibition signal, the comparator 22 outputs low while the voltage fluctuation detection circuit 26 outputs the prohibition signal. You may comprise so that it may be maintained at a level.

[0034]

As described above, according to the present invention,
When the motor drive voltage fluctuates, it is possible to continue driving the motor without being affected by it, and when the motor is overloaded, it is possible to control the motor so that an overcurrent does not flow. There is an excellent effect that has never been seen.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a motor drive control device according to an embodiment of the present invention.

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

FIG. 3A is a diagram showing another example of the voltage fluctuation detection circuit, and FIG. 3B is a diagram showing another example of the voltage fluctuation detection circuit.

[Explanation of symbols]

 10 Motor Drive Control Device 12 Motor 20 Control Circuit (Control Means) 22 Comparator (Comparison Means) 26 Voltage Fluctuation Detection Circuit (Motor Drive Voltage Monitoring Means)

Claims (1)

[Claims] 1. Comparing means for comparing a voltage value corresponding to a motor current with a threshold value for overload detection to detect an overload state of a motor, and monitoring the fluctuation of the motor drive voltage to drive the motor. When the voltage fluctuates by a predetermined width or more, the motor drive voltage monitoring means outputs the prohibition signal only for the time corresponding to the fluctuation width, and when the prohibition signal is not output, the overcurrent flows based on the output of the comparison means. A motor drive control device comprising: a control unit that controls the motor so that the motor is not turned on and that continues to drive the motor while the prohibition signal is output.