JP2000315883A - Radiation structure of control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power related to cooling by dividing a radiation structure and optimizing cooling efficiency in each cooling structure, and controlling the startup and stop of radiation for each divided configuration according to the amount of cooling. SOLUTION: Temperature sensors 9 and 10 with different temperature setting values are mounted on a radiator 1 for conducting heat being generated from a heat generation part to a fin for cooling. Then, the radiator 1 itself is designed integrally, the radiation structure is divided on packaging for forming ducts 5 and 6, and a radiation capacity can be turned on/off. With the structure, the startup temperatures of cooling fans 7 and 8 are detected by the temperature sensors 5 and 6, thus accurately controlling the startup of the on/off of the radiation fans 7 and 8 and hence reducing power related to radiation and reducing fan noise.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Generally, in a control device having a control portion, such as an electronic device, in which a usable ambient temperature is limited and a heat generation portion such as a power control device in a control device, a heat radiation design is generally performed under the following conditions. Designed.

(1) The specification of a device having a severe ambient temperature condition among the devices housed in the control device is defined as a temperature specification in the control device.

(2) At the maximum ambient temperature of the control device, a heat radiation design is performed so as to satisfy the temperature specification in the control device under the condition that the heat generating portion of the power control device or the like becomes maximum.

As described above, the heat radiation design does not exceed the maximum value of the ambient temperature of the electronic equipment constituting the control unit even under the worst condition in which the temperature around the control unit and the heat generation unit of the power control unit are maximized. Design as follows. However, in actual use of the control device, the period of use under the worst conditions is limited to a relatively short period. In general, the heat dissipation structure of the control device is performed in combination with a radiator and a heat dissipation fan to improve the heat dissipation efficiency. Electricity is consumed / operated, resulting in lower efficiency. An object of the present invention is to provide a heat dissipation structure that efficiently dissipates heat even under conditions other than bad conditions.

[0005]

2. Description of the Related Art FIG. 1 shows the overall configuration of a conventional control device. In the control device shown in FIG. 1, a heating unit such as a main circuit switching semiconductor of the power control device and the control unit are mounted in a housing having a closed structure in order to enhance dustproofness. In order to efficiently radiate the heat generated by the heat generating portion, the heat generating portion is fixed to the radiator 1 so that the thermal resistance of the contact portion is reduced. Radiator 1
Are mounted in a heat radiation duct 2 and dissipate heat by an air flow generated by a heat radiation fan 3 mounted on the heat radiation duct 2. In general, the heat generation amount of a heat generating portion, such as an inverter driving device, greatly fluctuates depending on the operation state of a driven motor. It is necessary to design the heat dissipation structure so that it has a heat dissipation capacity that does not exceed the maximum value of the ambient temperature of the electronic equipment that constitutes the control unit even at the maximum temperature of the ambient temperature specification of the control unit and the maximum heat generation amount of the heat generation unit. There is. In response to recent demands for energy saving, the use of inverter-based speed control has been increasing, but in this case, unlike the conventional constant speed control, the amount of heat generated by the main circuit heat-generating portion greatly changes depending on the speed control state. Therefore, in most cases, the heat generating structure designed under the maximum ambient temperature of the control device and the maximum heat generating condition of the heat generating portion operates in a state of excessive heat radiation.

FIG. 2 shows a heat radiating structure of a conventional control device in order to compare the conventional and the heat radiating structures of the present invention. In FIG. 2, 1 is a radiator that is mechanically and thermally connected to a heat generating portion such as a main circuit switching semiconductor of a power control device, and radiates generated heat through fins. A radiating duct 3 for guiding an air flow is a radiating fan for securing an air flow for securing a predetermined amount of heat radiation to the radiator fins.

Next, the operation of the electronic equipment having the strictest temperature conditions in the control device as the main circuit switching semiconductor of the power control device will be specifically described. The temperature to be managed by the switching semiconductor is a junction temperature and is expressed by Tjc [° C.], and the heat radiation is designed so as not to exceed Tjc under any use conditions. Here, the maximum value of the ambient temperature of the control device is Tamax [° C.], the maximum heating value of the switching semiconductor is Wmax [W], and the thermal resistance of the heat radiation fin is Rfin [° C. / W], the junction temperature Tjc of the switching semiconductor is

[0008]

Tjc = Rfin × Wmax + Tamax (1) Tjc is determined by the specifications specific to the switching semiconductor. Wmax is a use condition of the switching semiconductor, and Tamax is determined by a control device specification. R
The fin is given as the performance specification of the radiator under the condition of the air flow rate that can secure the highly efficient heat radiation of the radiator.
The heat radiation design is to design Rfin so as to satisfy the expression (1) under the condition of the air flow rate.

[0009]

Since the performance specification of the radiator is determined by the structure of the radiator itself, the ambient temperature of the control device T
less than amax or the heating value of the switching semiconductor is Wmax
If it is less than the above, the heat radiation more than necessary is performed with the set radiation fan flow rate. Unnecessarily starting the radiating fan has a problem of wasting fan drive power, generating noise due to the fan and airflow, and shortening the life of the fan.

In order to reduce unnecessary start-up time of the radiator fan shown in FIG. 2, a temperature sensor shown in FIG. 2 is provided to prevent the radiator fan from being started when the radiator is at a certain temperature or lower. It is also possible. However, even in this method, the heat radiation ability is originally excessive except under the worst condition, and the heat radiation fan 3 repeatedly starts and stops by turning on / off the temperature switch.
Further, the life of the fan itself is shortened due to the start / stop of the fan. Lower the set temperature of the temperature sensor 4 and start the fan /
There is a method of reducing the frequency of stoppage, but in this case, excessive heat dissipation occurs and wasteful fan drive power is consumed.

[0011]

As a method for avoiding an overheat radiation state, the conventional method of starting / stopping a fan is very inefficient. There are roughly the following two methods for efficiently controlling the heat radiation ability.

(1) Controlling the airflow flow rate (2) Switching the heat dissipation capability of the radiator In (1), a temperature sensor is provided on the radiator instead of a temperature switch, and the fan speed is determined based on the measured temperature. Although there is a control method, an additional circuit for controlling the temperature sensor and the speed is expensive. Further, the heat radiation efficiency of the radiator changes from the air flow, and there is an optimum air flow value. Therefore, the method of controlling the amount of heat radiation by changing the amount of air flow essentially lowers the efficiency.

Regarding (2), it is structurally difficult to mechanically switch the radiation efficiency of the radiator itself. According to the present invention, the radiator itself is designed as a single unit, and has a structure in which the heat radiation capability can be switched by dividing the duct of the heat radiation structure during mounting. In this structure, efficiency can be improved by designing the fans installed in each duct to have an airflow that maximizes the heat radiation efficiency of the radiator. The method of controlling the fan is basically ON / OFF control of starting / stopping, but in order to further improve the efficiency, the number of divided ducts may be increased. However, the number of divisions is determined in consideration of the cost increase by the division and the effect of improving the heat radiation efficiency.

According to the present invention, the heat radiation ducts are divided from the conventional method and the heat radiation fans are installed independently of each other. (1) The air flow can be controlled for each duct. (2) Since the capacity of the radiation fan of each duct can be divided into smaller ones, even if ON / OFF control is performed, the loss due to the starting power can be reduced compared to before the division. (3) By starting the minimum necessary fan In addition, it is possible to reduce noise and extend the life of the fan. In addition, by disposing a temperature sensor on the radiator and controlling the independently installed radiating fan, it is possible to reduce fan driving power, reduce fan noise, and extend the life of the fan.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. In FIG. 3, reference numeral 4 denotes a radiator that conducts heat from the heat generating portion to the fins and radiates heat, 5 and 6 denote divided heat radiation ducts (1/2) and heat radiation ducts (2/2), and 7 and 8 denote required flow rates. Radiating fan (1/2) and radiating fan (2
/ 2), 9 and 10 are temperature sensors (1/2) and temperature sensors (2 /
2) is shown.

The operation of the heat radiating structure of the present invention will be described based on the starting state of the fan according to the temperature change of the radiator 1. FIG. 4 shows the radiator temperature and the control state of the radiator fan when the radiator temperature rises sufficiently according to the present invention of FIG. The radiator temperature gradually rises below the radiating fan (1/2) starting temperature, and exceeds the radiating fan (1/2) starting temperature, and furthermore, exceeds the radiating fan (2/2) starting temperature to be in a steady state. Thereafter, the temperature rises in the reverse direction of the rise and decreases, and the temperature further exceeds the starting temperature of the radiating fan (2/2), and further exceeds the activating temperature of the radiating fan (1/2). At this time, the radiation fan (1/2) is activated,
The radiating fan (2/2) is activated in the state shown in FIG.
N, OFF when stopped.

In FIG. 4, the radiating fan (1/2) is activated at a temperature higher than the radiating fan (1/2) activation temperature, and the radiating fan (2/2) is activated at a temperature higher than the radiating fan (2/2) activation temperature. .

Next, FIG. 5 shows the time transition of the radiator temperature and the activation state of the radiator fan in the configuration diagram of the prior art of FIG. The radiator temperature gradually rises below the radiating fan starting temperature, and exceeds the radiating fan starting temperature to be in a steady state. Thereafter, when the temperature rises, the temperature shifts in the opposite direction and decreases, and after the heat radiation fan activation temperature, the temperature further decreases.

In FIG. 5, the radiating fan is started at a temperature higher than the radiating fan starting temperature. In the conventional technique shown in FIG. 5, the radiator fan is continuously activated when the radiator temperature exceeds the radiator fan activation temperature.

On the other hand, according to the present invention shown in FIG. 4, since the heat radiation capacity can be switched in an optimum state by dividing the heat radiation duct, the heat radiation fan (1) is provided by two temperature sensors installed on the heat radiator. / 2) By detecting the starting temperature and the radiating fan (2/2) starting temperature, the starting of the radiating fan can be properly controlled. In the graph showing the ON / OFF state of the heat radiating fan (2/2) in FIG. 4, it is not necessary to start the heat radiating fan (2/2) at a portion indicated by a thick line, so that the fan driving power can be reduced. Further, the capacity of the fan is divided into two compared to the conventional technology, and the bold line portion of the graph showing the ON / OFF state of the heat radiating fan (1/2) in FIG. 4 also saves power. Reduction of fan capacity
This is effective in reducing fan noise and extending the life of the fan.

The case described above shows a case where the temperature of the radiator rises sufficiently. The present invention is most effective in the case where the radiator operates constantly when the radiator temperature exceeds the radiating fan starting temperature. FIG. 6 shows the control state of the radiator temperature and the radiator fan according to the present invention when the radiator temperature rise is small.
FIG. 7 shows the radiator temperature and the control state of the radiator fan according to the conventional method when the radiator temperature rise is small.

In FIG. 7, when the temperature exceeds the radiating fan activation temperature, the radiating fan is activated, and the fan is activated until the temperature falls below the radiating fan activation temperature.

On the other hand, in the case of the present invention shown in FIG. 6, the radiator temperature exceeds the radiating fan starting temperature (1/2), but does not exceed the radiating fan starting temperature (2/2). Only fan (2/2). In the graph showing the ON / OFF state of the heat radiation fan (2/2) in FIG.
Since it is not necessary to start the heat radiating fan (2/2) at the portion indicated by the thick line, the fan driving power can be reduced. Further, the capacity of the fan is divided into two compared to the conventional technology, and the bold line portion of the graph showing the ON / OFF state of the heat radiation fan (1/2) in FIG. 6 also saves power. Further, since the heat radiating fan (1/2) can be constituted by a smaller fan than the heat radiating fan, it is effective in reducing fan noise and extending the life of the fan.

[0024]

As described above, according to the heat dissipating structure of the present invention, the heat dissipating fan can be started properly only when it is necessary for heat dissipating, and the optimum operation can be performed. Therefore, it is possible to reduce the power required for heat radiation, and to further reduce fan noise and extend the life of the fan.

[Brief description of the drawings]

FIG. 1 is a diagram showing the overall structure of a conventional control device.

FIG. 2 is a diagram showing a heat dissipation structure of a conventional control device.

FIG. 3 is a diagram showing one embodiment of a heat dissipation structure of the control device according to the present invention.

FIG. 4 is a diagram showing a time transition of a radiator temperature and a starting state of a radiator fan (when the radiator temperature rises sufficiently) in the configuration diagram of the present invention.

FIG. 5 is a diagram showing a time transition of a radiator temperature and a starting state of a radiator fan (when the radiator temperature rises sufficiently) in a configuration diagram of a conventional technique.

FIG. 6 is a diagram showing a time transition of a radiator temperature and a starting state of a radiator fan in the configuration diagram of the present invention.

FIG. 7 is a diagram showing a time transition of a radiator temperature and a starting state of a radiator fan in a configuration diagram of a conventional technique.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 radiator, 2 radiator duct, 3 radiator fan, 4 temperature sensor, 5 radiator duct (1/2), 6 radiator duct (2/2), 7 radiator fan (1/2), 8: heat dissipation fan (2/2), 9: temperature sensor (1/2), 10: temperature sensor (2/2).

Continued on the front page (72) Inventor Haruo Miura 603, Kandamachi, Tsuchiura-shi, Ibaraki Pref. In the Tsuchiura Works, Hitachi Ltd. F term (reference) 3L103 AA37 BB20 DD15 DD53 DD67 5E322 AA01 AB10 BA03 BA05 BB03 BB04 5F036 AA01 BB33 BB35 BB37

Claims (1)

[Claims] A radiator for radiating heat from a heat generating portion of a control device having a control portion including an electronic device and a heat generating portion such as a power control device, and supplying an air flow for heat exchange to the radiator. In the heat dissipation structure composed of the heat dissipation fan and the heat dissipation duct, the heat dissipation structure is divided and the heat dissipation efficiency is optimized for each heat dissipation structure, and the start / stop of the heat dissipation is controlled for each divided structure according to the heat dissipation amount The heat dissipation structure of the control device characterized by the above.