JPH10294164A - Heater control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To design a temperature control device using a heater to be capable of varying a control range by means of external signals and control temperature within a certain temperature range even if external sipnels have errors. SOLUTION: This device uses a first switch 5 whose set temperature is variable, a second switch 7 connected in series with the first switch 5, and a third switch 9 connected in parallel with them. normally, the first switch 5 controls temperature, and if the first switch 5 is kept closed as the result of a failure or an error signal, the second switch 7 controls temperature; if the first switch 5 is kept open, the third switch 9 controls temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling the temperature of a device by a heater using electric power, in which the temperature range to be controlled is made variable by an external signal and errors in the external signal are detected. The present invention relates to a technology capable of maintaining a temperature within a certain range. An example of a field in which such a heater control device is used is a temperature control device for an artificial satellite.

[0002]

2. Description of the Related Art For example, the equipment mounted on an artificial satellite gradually decreases in temperature except when using a large amount of electric power because it is exposed to outer space. Therefore, if the temperature of the device falls below a certain limit, the temperature must be raised using a heater. If you use a heater, the temperature will continue to increase gradually, but if it rises above a certain limit, you must turn off the heater to lower the temperature.

FIG. 5 is an explanatory view showing a conventional heater control device. In FIG.
2 is a heater that generates heat when an electric current flows, 3
Is a power line for supplying power to the heater, 4 is a temperature sensor for measuring the temperature of the heater installation portion, 5 is a switch for shutting off power to the heater, 6 is a certain temperature T6 set by the temperature measured by the temperature sensor 4. If the temperature is lower than -1, the switch 5 is turned on. If the temperature is higher than a certain temperature T6-2 set higher than T6-1, the switch 5 is turned off.
The following figure shows a circuit to perform.

As shown in the figure, when the temperature measured by the temperature sensor 4 is lower than the temperature T6-1, the circuit 6 closes the switch 5, power flows through the heater 2 via the power line 3, and the temperature of the equipment 1 rises. . Conversely, if the temperature measured by the temperature sensor 4 is higher than the temperature T6-2, the circuit 6 opens the switch 5, the power of the heater 2 is cut off, and the temperature of the device 1 drops. As a result, the temperature of the device is lower than the lower temperature limit T6-1 and the upper limit temperature T6-1.
It is kept between 6-2.

[0005]

The conventional heater control device is constructed as described above.
There are two types: a fixed temperature lower limit T6-1 and an upper limit T6-2, and a variable type that can be changed by an external signal. For example, the circuit 6 of the conventional heater control device normally used for artificial satellites uses a fixed set temperature, because the fixed set temperature type circuit has abundant achievements and few failures, This is because if the set temperature is variable, the temperature may not be maintained within the limit if an external signal is incorrect.
In particular, in the case of artificial satellites, once launched, humans cannot be constantly monitored nearby and cannot be repaired once they have broken down.
Therefore, a control circuit of a fixed temperature setting type is used.

Although the fixed temperature circuit has such an advantage, it has a disadvantage that the set temperature cannot be changed.
For example, in the case of equipment mounted on satellites, even if there is a request to change the set temperature after launch, it can not be changed because it uses a fixed set temperature circuit,
A circuit that can change the set temperature by an external signal could not be adopted because of the possibility of an external signal error or the likelihood of failure.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been made to make the temperature control range of the heater variable by an external signal, and to correct an external signal error or circuit error. An object of the present invention is to control the temperature of a device within a certain range even if a failure occurs.

[0008]

A heater control device according to the present invention comprises a first switch which is opened / closed by a circuit capable of changing a set temperature for opening / closing a switch by an external signal, and a first switch connected in series to the first switch. A second switch that is opened and closed by a temperature-fixed circuit being used and a third switch that is connected in parallel to these and that is opened and closed by another temperature-fixed circuit are used, and the first switch operates normally. Sometimes the first switch controls the heater on and off,
When the first switch is kept closed due to a failure, the second switch is responsible for turning the heater on and off,
When the first switch is kept open due to a fault, the third switch is configured to control the turning on and off of the heater.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a schematic diagram showing Embodiment 1 of the present invention, in which 1 is a target device whose temperature is to be controlled,
2 is a heater that generates heat when an electric current flows, 3
Is a heater power line for supplying current to the heater, 4 is a temperature sensor for measuring the temperature near the heater installation part, 5 is a switch for turning on and off the heater by cutting off the power line 3 on the way, and 6 is a temperature sensor 4 for measurement. A circuit 7 turns on the switch if the temperature is lower than a certain temperature T6-1 set by an external signal, and turns off the switch if the temperature becomes higher than another certain temperature T6-2 set by an external signal. A second switch connected in series with the switch 5 for turning on and off the heater power, and a temperature T measured by the temperature sensor is set to a temperature T set by the circuit 6.
If the temperature is lower than the set temperature T8-1 lower than 6-1, the second
A circuit that turns on the switch 7 and turns off the second switch 7 when the temperature becomes higher than another temperature T8-2 set higher than the temperature T6-2 set by the circuit 6, and 9 is connected in parallel with the switch 5 and the switch 7. The third switch 10 for turning on and off the heater power turns on the third switch 9 when the temperature measured by the temperature sensor is lower than the temperature T10-1 set lower than the temperature T8-1 set in the circuit 8. Another temperature T set higher than the temperature T8-2 set in 8
A circuit for turning off the third switch 9 when the voltage is higher than 10-2, and a signal 11 for setting the temperature of the circuit 6 from the outside.

FIGS. 2, 3 and 4 are explanatory graphs showing the relationship between the set temperatures of the three control circuits shown in the first embodiment of the present invention, in which the vertical axis represents temperature, the horizontal axis represents time, and T6. −
1 is the temperature at which the switch 5 is closed by the variable set temperature circuit 6, T6-2 is the temperature at which the switch 5 is opened by the variable set temperature circuit 6, and T8-1 is the switch 7 is closed by the fixed temperature circuit 8. The temperature, T8-2 is the temperature at which the switch 7 is opened by the fixed-temperature circuit 8, T10-1 is the temperature at which the switch 9 is closed by the fixed-temperature circuit 10, and T10-2 is the temperature at which the fixed-temperature circuit 10 is used. Indicates the temperature at which the switch 9 opens.

The operation of the first embodiment of the present invention will be described below with reference to FIGS. 1, 2, 3 and 4. First, a case where the variable set temperature control device is operating normally will be described with reference to FIGS. It is assumed that the temperature of the heater section is sufficiently low and all three switches 5, 7, and 9 are closed and the heater 2 is energized via the power line 3. At this time, the temperature starts to rise as shown by the curve in the graph of FIG. When the temperature reaches T6-2, the switch 5 is opened under the control of the circuit 6 of the set temperature variable type, but since the switch 9 is closed, power is supplied and the temperature continues to rise. When the temperature reaches T8-2, the switch 7 is opened under the control of the fixed temperature setting type circuit 8, but the switch 9
Is closed, power is supplied and the temperature continues to rise.
When the temperature reaches T10-2, the set temperature fixed type circuit 10
The switch 9 is opened by the control of. This makes heater 2
To the power supply, and the temperature of the device 1 starts to decrease. When the temperature reaches T6-1, the switch 5 is closed by the control of the circuit 6 of the set temperature variable type, but since the switch 7 is open, the power is cut off and the temperature continues to decrease. When the temperature reaches T8-1, the switch 7 is closed by the control of the fixed temperature circuit 8. As a result, energization of the heater 2 is started, and the temperature of the device 1 starts to rise. At this time, the switch 9 remains open. The temperature rises as it is and T6
When it reaches -2, the switch 5 is opened under the control of the circuit 6 of the set temperature variable type. As a result, the power supply to the heater 2 is cut off, and the temperature of the device 1 starts to decrease. At this time, the switch 9 remains closed. When the temperature reaches T6-1, the switch 5 is closed by the control of the circuit 6 of the set temperature variable type, and the switch 9 is also closed, so that the temperature starts to rise. Later device 1
Is continuously controlled between T6-1 and T6-2 by opening and closing the switch 5 under the control of the set temperature variable circuit 6. At this time, the switch 7 is normally closed, and the switch 9 is normally open. This achieves the initial goal.

Next, a case where the switch 5 remains closed due to a failure of the variable set temperature type circuit 6 or an error of the signal 11 from the outside will be described with reference to FIGS. I do. Now, it is assumed that the temperature of the sensor section is sufficiently low, the switches 7 and 9 are closed, and the heater 2 is energized via the power line 3. At this time, the temperature starts to rise as shown by the curve in the graph of FIG. Even if the temperature reaches T6-2, the switch 5 remains closed due to a failure, and since the switches 7 and 9 are also closed, power is supplied and the temperature continues to rise. When the temperature reaches T8-2, the switch 7 is opened under the control of the fixed temperature setting type circuit 8, but since the switch 9 is closed, power is supplied and the temperature continues to rise. When the temperature reaches T10-2, the switch 9 is opened under the control of the circuit 10 of the fixed temperature setting type. As a result, the power supply to the heater 2 is cut off, and the temperature of the device 1 starts to decrease. Even if the temperature reaches T6-1, the set temperature variable circuit 6
Has failed and the switch 5 remains closed, but since the switches 7 and 9 are open, power is cut off and the temperature continues to drop. When the temperature reaches T8-1, the switch 7 is closed and the switch 5 is closed by the control of the circuit 8 of the fixed temperature setting type, so that the power supply to the heater 2 is started and the temperature of the device 1 starts to rise. At this time, the switch 9 remains open. Thereafter, the temperature of the device 1 is similarly set to the fixed temperature circuit 8.
T8-1 and T8-
Continue to be controlled during two. As a result, the temperature of the device 1 is controlled within the range set by the fixed temperature circuit 8.

Finally, FIG. 1 and FIG. 4 show a case where the switch 5 is left open due to a failure of the variable set temperature type circuit 6 or an error of the signal 11 from the outside.
This will be described with reference to FIG. Now, it is assumed that the temperature of the sensor section is sufficiently low, the switches 7 and 9 are closed, and the heater 2 is energized through the power line 3. At this time, the temperature starts to rise as shown by the curve in the graph of FIG. When the temperature reaches T6-2, the switch 5 remains open due to a failure, but since the switch 9 is closed, power is supplied and the temperature continues to rise. When the temperature reaches T8-2, the switch 7 is opened under the control of the fixed temperature setting type circuit 8, but since the switch 9 is closed, power is supplied and the temperature continues to rise. When the temperature reaches T10-2, the switch 9 is opened under the control of the circuit 10 of the fixed temperature setting type. As a result, the power supply to the heater 2 is cut off, and the temperature of the device 1 starts to decrease. Even if the temperature reaches T6-1, the set temperature variable circuit 6
Has failed and the switch 5 remains open, and since the switch 9 is also open, power is shut off and the temperature continues to drop. When the temperature reaches T8-1, the switch 7 is closed by the control of the fixed temperature setting type controller 8, but since the switch is open, the power is cut off and the temperature continues to decrease. When the temperature reaches T10-1, the switch 9 is closed by the control of the circuit 10 of the fixed temperature setting type. As a result, the power supply to the heater 2 is started, and the temperature of the device 1 starts to rise. Thereafter, similarly, the temperature of the device 1 is changed to T10-1 and T10- by opening and closing the switch 9 under the control of the fixed-temperature circuit 10.
Continue to be controlled during two. As a result, the temperature is controlled within a range set by the fixed temperature circuit 10.

In contrast to the first embodiment, circuit 8
If the control temperature range is outside the control temperature range of the circuit 10, even if the variable temperature setting circuit 6 is normal, once the switch 7 is once opened for some reason, the circuit 10 Only the heater is controlled, and the control by the circuit 6 of the set temperature variable type, which is the initial target, cannot be achieved.

[0015]

According to the present invention, when the set temperature variable type circuit is normal, a predetermined temperature control can be realized by changing the control temperature range by an external signal during use while the external signal is being used. There is an effect that the temperature control can be continued even if the switch is opened or closed due to an error or a failure of the variable temperature setting circuit.

In particular, when using this device for thermal control of an artificial satellite, there is no need to constantly monitor from the ground, and repair can be performed even if a variable temperature setting circuit breaks down or an external signal is incorrect. There is an effect that it is not necessary.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing Embodiment 1 of a heater control device according to the present invention.

FIG. 2 is an explanatory diagram illustrating an operation of the heater control device according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an operation of the heater control device according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram showing an operation of the heater control device according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a conventional set temperature fixed type heater control device.

[Explanation of symbols]

1 Temperature control target equipment, 2 heaters, 3 heater power lines, 4 temperature sensors, 5 switches, 6 circuits,
7 switches, 8 circuits, 9 switches, 10 circuits, 1
1 signal.

Claims (1)

[Claims] A heater for generating heat, a temperature sensor for measuring a temperature near the heater, a power line for supplying a current to the heater, a first switch provided in the middle of the power line, When the temperature detected by the temperature sensor is lower than the first set temperature, the first switch is turned off.
N; a first circuit for turning off the first switch when the temperature is higher than a second set temperature higher than the first temperature; a second switch connected in series with the first switch; If the temperature detected by the temperature sensor is lower than a third set temperature which is set lower than any of the first and second temperatures, the second switch is turned on and any of the first, second and third switches is turned on. A second circuit for turning off the second switch when the temperature is higher than a fourth set temperature higher than the temperature; another power line connected in parallel with the power line; and a second circuit provided in the middle of the power line. And the third switch is turned on when the temperature detected by the temperature sensor is lower than a fifth set temperature set lower than any of the first, second, third, and fourth temperatures. First, second,
When the temperature is higher than the sixth set temperature which is set higher than any of the third, fourth, and fifth temperatures, the third switch is set to O
It comprises a third circuit that performs FF, and the current to the heater is controlled normally by the second and third switches even if the first switch or the first circuit fails. And heater control device.