JP4195981B2 - Motor drive device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to avoiding stoppage of a motor driving device due to a failure of a cooling fan built in an inverter or servo amplifier used in an industrial field or the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, with the progress of miniaturization of motor drive devices, it has been generally implemented to incorporate a cooling fan to prevent heating of power semiconductor elements and the like.
[0003]
However, the cooling fan is generally a short-life component, and the life of the cooling fan dominates the life of the motor driving device.
[0004]
Therefore, when the temperature of the power semiconductor element is low, such as when the ambient temperature of the motor drive device is low, it has been practiced to extend the life of the cooling fan by means such as stopping the cooling fan or reducing the rotational speed ( For example, see Patent Document 1).
[0005]
[Patent Document 1]
JP-A-9-117158 [0006]
[Problems to be solved by the invention]
However, when the cooling fan stops due to a failure, etc., if the motor drive device immediately takes protective measures to prohibit motor drive, the operation of the production machine or industrial machine incorporating the motor drive device will be stopped, resulting in a large economy. There was a problem such as the occurrence of an industrial loss.
[0007]
If the motor driving is continued when the cooling fan is stopped due to a failure, the temperature of the power semiconductor element easily reaches the protection temperature set value, so that the driving of the motor is stopped. On the other hand, if the protection temperature set value is set high from the beginning, the life of the power semiconductor element and the like may be shortened, and damage may be further increased.
[0008]
The present invention solves such a conventional problem, and ensures the safety of a driving device and the life of a power semiconductor element, etc. without stopping immediately when a failure of a cooling fan built in the motor driving device is detected. An object of the present invention is to provide a motor drive device that drives a motor.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a cooling fan having a power semiconductor element for driving a motor, a temperature detecting means for detecting the temperature of the power semiconductor element, and a failure detecting means for cooling the power semiconductor element. Storage means for preliminarily storing a plurality of protection temperature setting values for ensuring the life of the power semiconductor element, switching means for switching the protection temperature setting values according to the state of the cooling fan, and the protection temperature setting value exceeded And a protection means for stopping the driving of the motor, and when the cooling fan is rotating normally, the minimum value (initial value) is selected from the protection temperature setting values, and the initial value is exceeded. When the motor drive is stopped and a cooling fan failure is detected, a warning signal is issued to the host controller and the protection temperature set value is switched to a value higher than the initial value to Since Allow dynamic, while ensuring the longevity of the power semiconductor device can drive the motor, the operation of such production machines it is possible to continue a certain period.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
In order to solve the above problems, the motor drive device according to claim 1 selects the minimum value (initial value) from the protection temperature setting values when the cooling fan is rotating normally, and sets the initial value to When the motor temperature is exceeded, the motor is stopped. When a failure of the cooling fan is detected, a warning signal is issued to the host controller, and the protection temperature setting value is switched to a value higher than the initial value to allow motor driving. Therefore, even if the cooling fan stops due to failure, the motor can be driven while ensuring the short-term life of the power semiconductor element.
[0011]
In the motor drive device according to claim 2, n + 1 protection temperature set values are set in advance for n cooling fans, and the protection temperature set values are switched according to the number of failed cooling fans. In addition, the motor driving device can be operated while ensuring the safety of the driving device and the short-term life of the power semiconductor element.
[0012]
【Example】
An embodiment of the present invention will be described below with reference to the drawings.
[0013]
(Example 1)
The first embodiment is a motor drive device on which one cooling fan is mounted.
[0014]
In FIG. 1, a power semiconductor element 1 composed of a diode, an IGBT, or the like converts an input AC power source into DC, and then drives a motor by controlling voltage, current, and frequency.
[0015]
The power semiconductor element 1 is attached to a heat sink 2 and cooled by a cooling fan 3. This cooling fan 3 has a failure detection means, and is input to a microcomputer 4 for motor control. Further, the temperature of the power semiconductor element 1 is detected by a temperature detecting means 5 made of a thermistor or the like and input to the microcomputer 4.
[0016]
In the microcomputer 4, a protection temperature setting value for ensuring the safety of the power semiconductor element 1 is stored in advance in n + 1 stages according to the number n of the cooling fans 3, and the protection temperature setting value according to the failure state of the cooling fan 3. Switch. Hereinafter, description will be made with reference to the flowchart of FIG.
[0017]
First, when the cooling fan 3 is rotating normally, the microcomputer 4 selects the protection level value 1 (initial value) as the protection temperature setting value. If the temperature of the power semiconductor element 1 is less than or equal to the protection level value 1, the motor drive is permitted. If the temperature exceeds the protection level value 1, it is determined that there is an abnormality and the motor drive is stopped.
[0018]
The protection level value 1 is determined by a value obtained by reducing the junction temperature upper limit of the semiconductor element to 150 ° C. and the temperature upper limit of the component having a lifetime such as an electrolytic capacitor by the cooling fan 3 so that a long life can be expected. Set.
[0019]
Next, when a failure of the cooling fan 3 is detected, a warning signal 6 is issued to warn the stop of the cooling fan to the host controller, and at the same time, the microcomputer 4 sets the protection level value 2 higher than the protection level value 1. Switch.
[0020]
The protection level value 2 is set to a value that does not cause a problem in the operation of the motor driving device such as destruction of the power semiconductor element 1 without expecting a long life. In this embodiment, the temperature is set to about 120 ° C.
[0021]
Furthermore, when the protection level value 2 is exceeded, the motor drive is stopped. However, compared to the case where the motor drive is performed with the protection level value 1, the possibility that the motor drive can be continued for a certain period of time increases, and the cooling fan fails. At the same time, the production machine can be operated safely without an emergency stop. In addition, maintenance such as replacement of a cooling fan can be performed when there is no problem in the operation of the machine.
[0022]
In addition, if the host controller takes measures to keep the operating rate of the motor drive device low, even if the cooling fan motor 3 fails, the temperature increase of the motor drive device can be suppressed and the operation of the production machine can be prolonged. .
[0023]
In addition, the present invention can be applied to devices such as a welding machine and an uninterruptible power supply that are similarly equipped with a power semiconductor element and a cooling fan in addition to the motor drive device.
[0024]
(Example 2)
The second embodiment is a motor drive device in which two cooling fans are mounted, and three protection temperature setting values are stored in advance.
[0025]
Although not shown, when both cooling fans are normal, the microcomputer adopts the protection level value 1 (initial value) as the protection temperature setting value, and when a failure of one cooling fan is detected, the protection level Switch to number 2. Further, when a failure of two cooling fans is detected, the protection level value is switched to 3.
[0026]
For example, the protection level value 1 is 90 ° C., the protection level value 2 is 105 ° C., and the protection level value 3 is 120 ° C. As a result, when one cooling fan fails, a longer life can be expected than when two cooling fans fail, and a longer period until maintenance work such as replacement of the motor controller after the cooling fan failure occurs. Can be
[0027]
In the motor control device having n cooling fans, the protection temperature set value may be set in the range of 90 ° C. to 120 ° C. in n + 1 steps, and any number of units can be similarly implemented.
[0028]
【The invention's effect】
As is apparent from the above embodiments, according to the present invention, when a failure of the cooling fan is detected, the motor driving device drives the motor while ensuring the life of the power semiconductor element.
[0029]
This can prevent an emergency stop of the production machine and reduce operating loss. In addition, when there are n cooling fans, the protection temperature setting value can be set to n + 1 levels to continue the operation of production machines, etc. more safely. It can be carried out.
[Brief description of the drawings]
FIG. 1 is a block diagram of a motor control device in Embodiment 1 of the present invention. FIG. 2 is a flowchart in Embodiment 1 of the present invention.
DESCRIPTION OF SYMBOLS 1 Power semiconductor element 2 Heat sink 3 Cooling fan 4 Microcomputer (memory | storage means, switching means)
5 Temperature detection means 6 Warning signal 7 Power supply 8 Motor

Claims (2)

A power semiconductor element for driving a motor, a temperature detection means for detecting the temperature of the power semiconductor element, a cooling fan having a failure detection means for cooling the power semiconductor element, and protection for ensuring the life of the power semiconductor element Storage means for storing a plurality of temperature setting values in advance, switching means for switching the protection temperature setting value according to the state of the cooling fan, and protection means for stopping the driving of the motor when the protection temperature setting value is exceeded. When the cooling fan is rotating normally, select the minimum value (initial value) from the protection temperature setting value, stop the motor drive when the initial value is exceeded, and trouble the cooling fan. A motor drive device that, when detected, issues a warning signal to the host controller and switches the protection temperature set value to a value higher than the initial value to permit motor drive. The motor drive device according to claim 1, wherein n + 1 protection temperature set values are set in advance for n cooling fans, and the protection temperature set values are switched according to the number of failed cooling fans.

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