JPH07154976A - Operating method of inverter cooling fan - Google Patents

Abstract

PURPOSE:To make the life of a cooling fan for an inverter apparatus long by a cooling fan operated by temperature a inside the apparatus. CONSTITUTION:The temperature of a converter module 21a and an inverter module 22a which constitute a main circuit for an inverter apparatus and which form its main heat generating sources is detected indirectly by a thermistor 24 via the temperature of a cooling fan 23. In a control circuit 25 which receives a detected temperature, whether the detected temperature is high or low is compared with its set temperature by a comparator 25a. According to its compared result, an operating instruction or a stop instruction with reference to a cooling fan 14 is output by an operation and instruction part 25b. That is to say, the cooling fan 14 is operated intermittently according to the relationship between the detected temperature by the thermistor 24 and the set temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating a cooling fan corresponding to the internal temperature of an inverter device.

[0002]

2. Description of the Related Art As a conventional method of operating an inverter cooling fan of this type, a method according to the circuit diagrams illustrated in FIGS. 3 and 4 is known. In both of these figures, constituent elements having the same function are designated by the same reference numeral. First, FIG. 3 is a circuit diagram corresponding to an operating method for keeping the cooling fan in an always operating state while a control power supply in the inverter device is established. The AC motors 4 forming the load of the device 2 are power circuit breakers.

Here, the inverter device 2 uses a diode as its rectifying element to convert its AC input into DC, a rectifying voltage smoothing capacitor C _f ,
A transistor 13 having a commutation diode is used as its switching element, and an inverter section 12 for converting the direct current input into a desired alternating current and a control section 13. In addition, the control unit 1
Reference numeral 3 includes a DC / DC converter 21 that supplies DC control power to each operating unit of the inverter device 2, and a control circuit 22 that outputs a control command signal to each switching element of the inverter unit 12.

Further, the cooling fan 14 is for cooling the inside of the inverter device, and is a DC electric fan directly driven by the output of the DC / DC converter 21. That is, the cooling fan 14 is always operated in the normal output state of the DC / DC converter 21.
Next, FIG. 4 is a circuit diagram corresponding to an operating method for keeping the cooling fan in an always operating state while the AC input is being applied to the inverter device, and is different from FIG. 3 only with respect to the cooling fan.

That is, a DC electric cooling fan 14 shown in FIG.
Is replaced by an AC electric cooling fan 15, and its AC input is shared with the converter unit 11. Therefore, the cooling fan 15 is always in the operating state when the power circuit breaker 4 is closed.

[0006]

According to the conventional method of operating an inverter cooling fan as described above, if the cooling fan is of the AC drive type, the cooling fan is not operated while AC power is being applied to the inverter device according to FIG. If the DC drive type is used, the DC / DC converter 21 in the inverter is normally operated in the normal output state according to FIG. In either case, the cooling fan is operated regardless of the internal temperature of the inverter device.

On the other hand, regarding this type of cooling fan, for example, the Japan Electrical Manufacturers' Association recommends replacing the cooling fan within three years due to mechanical wear such as bearing deterioration inside the fan. For this reason, the cooling fan has the shortest life among the parts used in the inverter device, and requires a considerable amount of time and cost for maintenance and inspection including replacement of the cooling fan.

In view of the above, the present invention has an object to provide an operating method for a cooling fan of an inverter device, which can extend its life.

[0009]

In order to achieve the above object, in the method of operating an inverter cooling fan according to the present invention, 1) the invention of claim 1 is to detect the temperature at a predetermined position inside the inverter device, and Provided are means for comparing the temperature detected by the detecting means and the set temperature thereof, and operation command means for instructing the fan for internal cooling of the inverter device to operate or stop the fan for cooling the inside of the inverter device in accordance with the result of the comparison of the two temperatures. The cooling fan is operated when the detected temperature is higher than the set temperature. 2) According to a second aspect of the present invention, a fan for cooling the inside of the inverter device receives a temperature detecting device at a predetermined position inside the inverter device and a voltage that increases in accordance with a predetermined relationship with the temperature detected by the detecting device as an input. And a voltage control means for outputting a voltage applied to the drive motor of (1) to control the number of revolutions so that the detected temperature is increased and the speed is increased.

[0010]

The amount of heat generated in the internal storage elements of the inverter device, or the internal temperature of the device according to this amount of heat generation, varies greatly depending on the operating condition of the inverter device, such as the stopped state or the load factor during its operation. Also, the temperature distribution inside the inverter device is not uniform.

On the other hand, the internal cooling fan of the inverter device is intended to keep the internal temperature of the device, particularly the temperature at a predetermined internal position requiring the strictest temperature control, below the predetermined value. It is appropriate that the device is operated in accordance with the internal temperature of the device, particularly the temperature condition at the internal predetermined position as described above. In accordance with the above, the present invention designates both the converter module and the inverter module forming the main circuit as the internal predetermined positions requiring the strictest temperature control in the inverter device, and corresponding to the temperature states of both, the internal cooling The fan is controlled as follows. That is, 1) The invention of claim 1 controls the internal cooling fan so as to operate when the temperature at the predetermined position inside the inverter device becomes higher than the set temperature and to stop when the temperature becomes lower than the set temperature. 2) According to the invention of claim 2, the number of rotations of the internal cooling fan is changed according to the level of the temperature at the predetermined position inside the inverter device, that is, the temperature of the predetermined position is raised together with the predetermined temperature. Is applied to the fan driving electric motor to control the rotation speed of the internal cooling fan so as to increase the speed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the control circuit diagrams illustrated in FIGS. In both of these figures, constituent elements having the same function are designated by the same reference numeral. First, FIG. 1 shows a first embodiment of the present invention according to claim 1, and 21a and 22a are a converter module and an inverter module respectively constituting a main circuit of an inverter device, wherein 21a is for rectification. The diode 22a has a switching transistor and a commutation diode as main constituent elements, and both are main heat sources in the inverter device.

Reference numeral 23 is a cooling fin common to both modules, 24 is a thermistor as a temperature detecting means for indirectly detecting the temperature of both modules via the temperature of the cooling fin 23, and 14 is cooling for the cooling fin 23. I am a fan. Further, 25 is a control circuit, which is the thermistor 2
4 is composed of a comparator 25a for comparing the detected temperature and its set temperature with each other, and an operation command section 25b for issuing a command signal for operating or stopping the cooling fan 14 according to the comparison result by this comparator. If the detected temperature is higher than the set temperature, the command signal commands the operation, and if the detected temperature is low, it commands the stop.

That is, the cooling fan 14 is intermittently operated according to the level relationship between the temperature detected by the thermistor 24 and its set temperature. Next, FIG. 2 shows a second embodiment of the present invention according to claim 2, wherein the control circuit 25 in FIG. 1 is replaced by a control circuit 26. Here, the control circuit 26 calculates and outputs a voltage that increases in accordance with a predetermined relationship as the temperature detected by the thermistor 24 rises, as an applied voltage of the fan driving electric motor, and performs A / D conversion to perform signal conversion of the detected temperature. 26a, and a voltage controller having a predetermined relationship with the output signal of the converter 26a, that is, a voltage control section for calculating and outputting as a voltage applied to the fan driving motor a voltage that increases in a predetermined relationship with the increase of the output signal. 26b.

That is, the cooling fan 14 is speed-controlled so that its rotational speed increases in accordance with a predetermined relationship as the temperature detected by the thermistor 24 rises, and the amount of cooling air is adjusted. The drive power source for the cooling fan motor according to the control circuit configuration shown in FIGS. 1 and 2 can be either AC or DC.

[0016]

According to the present invention, there is provided a method for operating an inverter cooling fan, a means for detecting a temperature at a predetermined internal position of the inverter device, a means for comparing the temperature detected by the detecting means with a set temperature thereof, and this comparison. Means for instructing the internal cooling fan of the inverter device to operate or stop the cooling fan according to the result of the comparison between the two temperatures by the means, and to operate the cooling fan when the detected temperature is higher than the set temperature. Or a voltage control means for outputting the voltage that increases in accordance with a predetermined relationship with the temperature detected as an input to the detected temperature as an applied voltage to the driving motor of the cooling fan, and the detected temperature By controlling the rotation speed of the cooling fan so as to increase the temperature and increase the speed, the main or control of the inverter device is performed. Compared with the case of the conventional operating method in which the cooling fan is always in the operating state regardless of the operating state of the power supply, the operation of the cooling fan in accordance with the internal temperature of the inverter device In the case of the operating method of the present invention in which stop or rotation speed control is performed, the degree of wear and deterioration of rotating mechanical system parts such as the bearing of the cooling fan is reduced, and the life of each part such as the bearing is extended. Therefore, it is possible to reduce the time and cost required for complicated maintenance and inspection work including replacement of the cooling fan.

[Brief description of drawings]

FIG. 1 is a control circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a control circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a circuit diagram showing a first embodiment of the prior art.

FIG. 4 is a circuit diagram showing a second embodiment of the prior art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC power supply 2 Inverter device 3 AC electric motor 4 Power circuit breaker 11 Converter section 12 Inverter section 13 Control section 14 Cooling fan 15 Cooling fan 21 DC / DC converter 21a Converter module 22 Control circuit 22a Inverter module 23 Cooling fin 24 Cooling thermistor 25 Control circuit 25a Comparator 25b Calculation command section 26 Control circuit 26a A / D converter 26b Voltage control section

Claims (2)

[Claims] 1. An inside of the inverter device according to a temperature detecting means at a predetermined position inside the inverter device, a comparing means for comparing a temperature detected by the detecting means with a set temperature thereof, and a result of a comparison between the two temperatures by the comparing means. An operating method of an inverter cooling fan, comprising: an operation command means for instructing a cooling fan to operate or stop the cooling fan, and to operate the cooling fan when the detected temperature is higher than a preset temperature. 2. A temperature detecting means at a predetermined internal position of the inverter device, and a voltage, which is inputted with the temperature detected by the detecting means and increases in accordance with a predetermined relationship as the temperature rises, is applied to a drive motor of an internal cooling fan of the inverter device. A method for operating an inverter cooling fan, characterized in that a voltage control means for outputting as a voltage is provided, and the rotation speed is controlled so as to increase the detected temperature and increase the speed.