JP2006296165A - Motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor controller where shift to a fail mode is inhibited when an overheat protection circuit operates and an initialization operation becomes unnecessary when the overheat protection circuit is normally restored. <P>SOLUTION: In the motor controller, a motor is provided with the overheat protection circuit interrupting driving current of the motor when the temperature of the motor exceeds a prescribed temperature. A driving signal is supplied to an output circuit based on the rotation detection signal of the motor detected by a rotation detection sensor, and driving current supplied to the motor is controlled. The controller is provided with an estimating means for estimating the operation of the overheat protection circuit from the rotation detection signal which the rotation detection sensor outputs and the driving signal supplied to the output circuit and a means for inhibiting fail judgment when the operation of the overheat protection circuit is estimated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor control device, and more particularly to a motor control device for a motor having an overheat protection circuit.

  For example, in a motor control device such as a power window of a vehicle, position information representing a window moving position is generated from a rotation detection signal output by a hall element provided in the motor, and control such as prevention of foreign object pinching is performed based on this position information. Is going. In order to store the position information, a storage medium such as an EEPROM is generally used.

  However, if power can be constantly supplied to the motor control device, the position information can be retained without using an expensive storage medium. However, position information is lost in the event of a momentary power interruption, etc., so the expected rotation signal for the drive output to the motor cannot be obtained, and the overheat protection circuit (PTC) is activated due to a rise in motor temperature. When the power supply to the motor is cut off, an abnormality determination is made and the mode is changed to the fail mode, and a measure for prohibiting a specific operation is taken.

  In Patent Document 1, in an intelligent power switch having circuits such as overcurrent protection, overcurrent protection, and overvoltage protection, when the power is not supplied to the load, the cause is due to the protection function differential. It is described that it is determined whether the load is due to an open load.

Moreover, in patent document 2, when the pinching of a foreign material is detected, it moves to the direction which opens glass rather than the movement stop of a window glass. In addition, it is described that the energization cut is performed when heating is detected by the overheat protection circuit.
JP-A-10-14089 JP 2000-73655 A

  In a conventional motor control device that does not have a storage medium, the mode is shifted to the fail mode immediately after the overheat protection circuit is activated due to foreign matter being caught. In addition, the operation of the overheat protection circuit cuts off the energization of the motor, the motor temperature decreases, and the overheat protection circuit returns to normal. At this time, even if the caught foreign matter is removed, a predetermined initialization operation is required to shift from the fail mode to the normal mode. This initialization operation is, for example, an operation of fully opening the power window and resetting position information indicating the window movement position.

  As described above, the conventional motor control device having no storage medium has a problem that even if the overheat protection circuit returns to normal, a predetermined initialization operation is required, and the initialization operation is troublesome.

  The present invention has been made in view of the above points, and when the overheat protection circuit is activated, the transition to the fail mode is prohibited, and the initialization operation when the overheat protection circuit returns to normal becomes unnecessary. An object is to provide a motor control device.

The motor control device of the present invention includes an overheat protection circuit that cuts off the driving current of the motor when the motor temperature exceeds a predetermined temperature, and based on the rotation detection signal of the motor detected by the rotation detection sensor. In a motor control device for supplying a drive signal to an output circuit and controlling a drive current supplied to the motor,
An estimation means for estimating an operation of the overheat protection circuit from a rotation detection signal output from the rotation detection sensor and a drive signal supplied to the output circuit;
By having a fail determination prohibiting means for prohibiting a fail determination when the operation of the overheat protection circuit is estimated,
When the overheat protection circuit is activated, the transition to the fail mode is prohibited, and the initialization operation when the overheat protection circuit returns to normal becomes unnecessary.

  In addition, the estimation unit of the motor control device includes the overheat protection circuit based on a time when the rotation of the motor obtained from the rotation detection signal is stopped and a time when a drive current is supplied to the motor obtained from the drive signal. Can be estimated.

  According to the present invention, when the overheat protection circuit is activated, the transition to the fail mode is prohibited, and the initialization operation when the overheat protection circuit returns to normal becomes unnecessary.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a block diagram of a first embodiment of a motor control device of the present invention. In the figure, the motor control device is roughly divided into a control unit 10 and an output unit 20.

  The calculation unit 11 in the control unit 10 generates a drive signal for driving the motor in accordance with the position information and an operation signal supplied from the outside.

  The output circuit 12 switches the output transistor according to the drive signal supplied from the calculation unit 11 and supplies the drive current of the motor to the output unit 20.

  The position information generation circuit 13 determines the rotation direction of the motor from the rotation detection signal of the pulse waveform supplied from the output unit 20 and counts the number of pulses of the rotation detection signal to generate position information indicating the window moving position. , Supplied to the calculation unit 11.

  The output transistor of the output circuit 12 is turned on when the drive signal is at a high level or a low level, and outputs the drive current of the motor 21. In the calculation unit 11, the output transistor is output from the high level or low level period of the drive signal. Can recognize on-time. Further, the position information generation circuit 13 detects the pulse period of the rotation detection signal and notifies the calculation unit 11 of it.

  The motor 21 in the output unit 20 rotates when supplied with a drive current from the output circuit 12. The overheat protection circuit (PTC) 22 increases the resistance value when the motor temperature rises, and cuts off the drive current of the motor 21 when the motor temperature exceeds a predetermined temperature.

  The rotation detection sensor 23 is composed of, for example, a Hall element, detects rotation of the motor 21, generates a rotation detection signal, and supplies the rotation detection signal to the position information generation circuit 13.

  FIG. 2 is a flowchart of the failure determination process executed by the calculation unit 11. This process is repeatedly executed at a predetermined cycle when the calculation unit 11 drives the motor 21.

  In the figure, in step S11, the calculation unit 11 determines whether or not the pulse period W of the rotation detection signal notified from the position information generation circuit 13 exceeds a threshold value Wth. If the pulse period W does not exceed the threshold value Wth, the process proceeds to step S15 and the normal mode is maintained.

  When the pulse period W exceeds the threshold value Wth, the process proceeds to step S12, and the calculation unit 11 determines whether or not the ON time A of the output transistor exceeds the threshold value Ath. When the on-time A of the output transistor does not exceed the threshold value Ath, the process proceeds to step S15 and the normal mode is maintained.

  When the ON time A of the output transistor exceeds the threshold value Ath, the process proceeds to step S13, and it is determined whether or not the motor temperature T exceeds the threshold value Tth.

  Here, as shown in FIG. 3, when the pulse period W is equal to or greater than the predetermined value W3 and the ON time A of the output transistor is equal to or greater than the predetermined value A3, it is estimated that the motor temperature T exceeds the threshold value Tth. . Note that the relationship is Wth> W3> W2> W1, Ath> A3> A2> A1, Tth> T2> T1. T1 is the estimated motor temperature when the output transistor is on time A1 in the pulse period W1, and T2 is the estimated motor temperature when the output transistor is on time A2 in the pulse period W2.

  Since the overheat protection circuit 22 operates with the motor temperature T being a threshold value (Tth−α), it is considered that the overheat protection circuit 22 is in operation when the motor temperature T is estimated to exceed the threshold value Tth.

  If the motor temperature T is less than or equal to the threshold value Tth, the process proceeds to step S14, where a fail determination is made and the process shifts to the fail mode.

  On the other hand, if the pulse period W is equal to or greater than the predetermined value W3, the ON time A of the output transistor is equal to or greater than the predetermined value A3, and the motor temperature T exceeds the threshold value Tth, it is considered that the overheat protection circuit 22 is operating. Without shifting to the fail mode, the process proceeds to step S15 to maintain the normal mode.

  In this way, if the motor temperature T exceeds the threshold value Tth, it is considered that the overheat protection circuit 22 is operating, and the transition to the fail mode is prohibited. Therefore, the motor 21 is energized by the operation of the overheat protection circuit 22. When the motor 21 is shut off and the temperature of the motor 21 is lowered, and the overheat protection circuit 22 returns to normal, normal operation can be performed without the need for a troublesome initialization operation.

  In the above embodiment, the power window of the vehicle has been described as an example. However, the motor control device of the present invention can be applied to a power slide door, a power slide sunroof, a power back door, and the like, and is not limited to the above embodiment. Absent.

  Step S13 corresponds to an estimation unit and a failure determination prohibition unit described in the claims.

It is a block diagram of a 1st embodiment of a motor control device of the present invention. It is a flowchart of the process for fail determination. It is a figure which shows the relationship between a pulse period and ON time, and a motor temperature estimated value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Control part 11 Calculation part 12 Output circuit 13 Position information generation circuit 20 Output part 21 Motor 22 Overheat protection circuit 23 Rotation detection sensor

Claims (2)

When the motor temperature exceeds a predetermined temperature, the motor is provided with an overheat protection circuit that cuts off the drive current of the motor, and the drive signal is supplied to the output circuit based on the rotation detection signal of the motor detected by the rotation detection sensor. In the motor control device for controlling the drive current supplied to the motor,
An estimation means for estimating an operation of the overheat protection circuit from a rotation detection signal output from the rotation detection sensor and a drive signal supplied to the output circuit;
A motor control apparatus comprising: a fail determination prohibiting unit that prohibits a fail determination when the operation of the overheat protection circuit is estimated. The motor control device according to claim 1,
The estimation means estimates the operation of the overheat protection circuit from a time when the rotation of the motor obtained from the rotation detection signal is stopped and a time when a drive current is supplied to the motor obtained from the drive signal. A motor control device.

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