JPH0320651Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Purpose of invention] [Industrial application field] This invention relates to improvement of electric kotatsu.

[Prior Art] An electric kotatsu obtains a target temperature inside the kotatsu by varying the amount of electricity supplied to a heater installed on the ceiling of the tower. Conventionally, the amount of current supplied to the heater has been controlled using a phase control method consisting of a negative resistance element (POSISTOR), a bidirectional three-terminal thyristor (TRIAT), etc., and a temperature detection system using a thermostat. This is done using an ON-OFF control method that turns the electricity on and off. Figure 11 shows the changes in the temperature inside the kotatsu in the phase control method and the ON-OFF control method. ) maximum target temperature 7Q1 and intermediate target temperature 4Q when set in 7 stages
2 and each temperature change is shown. In other words,
In the phase control method, the temperature inside the kotatsu gradually rises and reaches the target temperature for both target temperatures Q1 and Q2, as shown by the solid line, while in the ON-OFF control method, the temperature inside the kotatsu rises and falls as shown by the dotted line, reaching the target temperature. has reached.

However, in the phase control method, the rise is good at the highest target temperature Q1, but becomes slow at other target temperatures, for example, the intermediate target temperature Q2.
For this reason, the rise characteristic of the temperature inside the kotatsu at the time of starting the current supply is poor, and the temperature does not reach the target temperature quickly. on the other hand,
In the ON-OFF control method, as shown in the figure, the difference in temperature within the kotatsu increases as the heater energization is turned on and off, and as the target temperature becomes lower, the time it takes for the energization to turn off becomes faster. For this reason, similarly to the phase control method, the rise characteristics of the temperature inside the kotatsu are poor.

[Problems to be solved by the invention] As described above, the conventional control method has poor rise characteristics of the temperature inside the kotatsu.

Therefore, in order to solve the above-mentioned problems, the present invention aims to provide an electric kotatsu that improves the rise characteristics of the temperature inside the kotatsu and provides an optimal temperature inside the kotatsu.

[Structure of the invention] [Means for solving the problem] The invention uses a temperature sensor installed on the ceiling of the tower, and a temperature sensor that determines each target temperature according to the optimum temperature change to reach these target temperatures. The control information section has a control information section in which each of the target achieved temperatures and the energization time determined for each of these target achieved temperatures are set, and a control information unit that fully energizes the heaters when starting to energize the heaters installed on the ceiling of the tower. After that, a temperature control unit compares the temperature detected by the temperature sensor with the target achieved temperature, determines the elapse of the energization time, and sequentially reduces the energization rate to the heater according to the target temperature to control the target temperature. This is an electric kotatsu that attempts to achieve the above objectives.

[Function] With the provision of such a means, the heater is fully energized at the start of energization, and after that, the temperature detected by the temperature sensor and the target achieved temperature are compared, and the energization time is determined. The progress is determined, and the energization rate to the heater is sequentially reduced in accordance with each target temperature, thus controlling the temperature inside the kotatsu to the target temperature.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an electric kotatsu, FIG. 2 is an external view of the electric kotatsu, and FIG. 3 is an external view of an electric kotatsu controller (hereinafter abbreviated as controller). An AC power supply 2 is connected to the controller 1, and the power of this AC power supply 2 is outputted from a power cord 3 to a connection cord 6 through a power switch 4 and a noise filter 5 in the controller 1, and then outputted to a connection cord 6. The power is supplied to a heater H and a fan motor M provided on the ceiling of the tower 7 through a connection plug (not shown) provided on the connection cord 6. Note that the connection plug is connected to a connection terminal 8 of the tower 7.

By the way, the configuration inside the controller 1 is as follows. This controller 1 is provided with a first control section 9 and a second control section 10 which are composed of a microcomputer, and the first control section 9 controls the heater H.
The second control section 10 controls the drive of the fan motor M. The first control section 9 then controls the second control section 1.
0 and monitors the fan motor control by the second control section 10, while the second control section 10 monitors the fan motor control signal fm sent from the first control section 9. 1st by taking signal hm
The heater control by the control section 9 is monitored. Note that the fan motor control signal fm is
The heater control signal is supplied to the gate of the triax 11 connected in series with
hm is configured to be supplied through a protection circuit 12 to the gate of a triac 13 connected in series to the heater H.

Now, a temperature sensor S provided on the connection plug is connected to the first control section 9, and has a function of changing the energization rate to the heater H based on the temperature detected by the temperature sensor S. There is. In other words, this first control section 9 has a temperature control system that is set for each target temperature within the kotatsu according to the optimum temperature change to reach each target temperature, and a temperature that is set for each target temperature. Functions as a control information section with the energization time set, and fully energizes the heater H at the start of energization to the heater H, and then compares the temperature detected by the temperature sensor S with the target achieved temperature and energizes. It is provided with a function as a temperature control section that determines the passage of time and sequentially reduces the energization rate to the heater H in accordance with the target temperature to control the target temperature.

Further, the phase control by the heater control signal hm sent from the first control section 9 is performed by the zero cross detection circuit 1.
4, the triax 13 is ignited at the zero cross position to supply electric power to the heater H. As a result, the supplied power waveform becomes as follows. If the energization rate is 100%, the fourth
As shown in Figure A, if all the power is supplied to the heater H and the energization rate is 60%, as shown in Figure 4B, positive half-wave rectification is supplied to the heater H, and only one of the negative half-waves is supplied.
10% is supplied to heater H. Hereinafter, similarly, FIG. 4C shows the waveforms when the energization rate is 55%, FIG. 4D shows the waveforms when the energization rate is 50%, and FIG. 4E shows the waveforms when the energization rate is 45%.

On the other hand, the second control section 10 has a function of variably controlling the rotation speed of the fan motor M according to the internal temperature of the kotatsu. In other words, the target temperature is the highest target temperature 7
If set to , the rotation speed of the fan motor M is always controlled to a high rotation speed, and if other target temperatures are set to 6 to 1, the fan motor M will be controlled when the temperature inside the kotatsu reaches a predetermined temperature. The rotational speed of the engine is controlled by switching from a high rotational speed to a low rotational speed.

The first control section 9 is connected to a clock circuit 15 and a display circuit 16 for each target temperature setting strong 7 to weak 1 shown in FIG. A setting switch 17 such as a setting switch (low, high) for setting 7 to 1 and a clock circuit 18 are connected. Each control section 9, 10 is supplied with a DC voltage from a rectifying and smoothing circuit composed of a transformer T, a diode bridge DB, and a capacitor (not shown).

The protection circuit 12 is for detecting disconnection or short-circuiting of the temperature sensor S and overheating of the heater H to prevent abnormalities from occurring, and specifically has a configuration shown in FIG. 5. That is, a disconnection detection circuit 20 and a short circuit overheat detection circuit 21 are provided, and these circuits 2
One end of the temperature sensor S is connected to the "-" side input terminal of the comparator 22 and the "+" side input terminal of the comparator 23. Then, a resistive voltage divider circuit consisting of resistors R1 and R2 is connected to the "+" side input terminal of the comparator 22 so that a comparison voltage V1, which is slightly lower than the level at which the detection voltage Vs generated by the temperature sensor S is disconnected, is applied. is connected. Therefore, normally, V1>Vs and a high level signal is output from the comparator 22.
When the wire is disconnected, V1<Vs and a low level signal is output. In addition, the detection voltage appearing by the temperature sensor S is connected to the "-" side input terminal of the comparator 23 of the short circuit overheat detection circuit 21.
Resistors R3 and R4 are connected so that a comparison voltage V2, which is slightly higher than the level when Vs is short-circuited or overheated, is applied.
A resistive voltage divider circuit is connected. Therefore, normally, when Vs>V2, a high level signal is output from the comparator 23, and in the event of a short circuit or overheating,
When Vs<V2, a low level signal is output. Note that terminal Z is a comparator.
The first controller 9 is connected to the first controller 9 via a controller (not shown). On the other hand, the cutoff control circuit 24, the first and second
Cutoff circuits 25 and 26 are provided, and the output signals of the respective comparators 22 and 23 are connected to the first cutoff circuit 25.
It is connected to the base of the NPN transistor Q1. The cutoff control circuit 24 is provided with NPN transistors Q2 and Q3, and the transistor Q
2, the heater control signal from the first control section 9
hm is added, and a second
A signal from the control section 10 is added. The collector of transistor Q2 is connected to the base of transistor Q1, and the collector of transistor Q3 is connected to the base of transistor Q4. The gate of triac 13 is connected to the emitter of transistor Q4 via resistor R5. Therefore, the output of each comparator 22, 23 becomes low level, transistor Q1 becomes non-conductive, and
The transistor Q is controlled by the signal from the second control section 10.
4 becomes non-conductive, the transistor 13 is not ignited and the current supply to the heater H is stopped.

Next, temperature control of the electric kotatsu constructed as described above will be explained.

First, the temperature control flowchart shown in FIG. 6 for the case where the target temperature is set to the highest target temperature 7.
The explanation will be as follows. When the power switch 4 is turned on and power supply to the heater H is started, the first control section 9 adjusts the maximum target temperature in step s1 to the maximum target temperature shown in FIG. 7 based on the detected temperature G1 of the temperature sensor S. target achieved temperatures A1, B1, C1, D1
First, it is determined whether A1 has been reached, and at the same time, in step s2, it is determined whether 15 minutes have elapsed since the start of energization to the heater H. Based on this judgment, if the detected temperature G1 of the temperature sensor S is below the target achieved temperature A1 and the elapsed time is within 15 minutes, the energization rate to the heater H is set to 100%. In addition, in the case of setting the maximum target temperature, the first control unit 9 detects the temperature M of the protection net 27 provided in the tower 7, and sets the protection net temperature M
The temperature is controlled so that the temperature does not exceed the standard temperature F for the tower protection net. After this, the detected temperature G of the temperature sensor S section is
1 is equal to or higher than the target achieved temperature A1, or if more than 15 minutes have elapsed, the process moves to steps s4 and s5, and it is determined whether the target achieved temperature is equal to or lower than the target achieved temperature B1 and whether the elapsed time is within 30 minutes. Based on this judgment, the target achieved temperature B
If it is less than 1 and the elapsed time is less than 30 minutes, the energization rate to the heater H is changed to 60% as shown in FIG. Then, within 30 minutes, the temperature sensor S
When the detected temperature G1 of the heater becomes equal to or higher than the target achieved temperature B1, the process moves to step s7, where it is determined whether the detected temperature G1 is equal to or lower than the target achieved temperature C1, and the energization rate to the heater H is set to 50%.
shall be. Note that a control may be added to set the energization rate to the heater H at 55% by inserting a determination that the time has elapsed within 45 minutes, as in steps s9 and s10. In this way, the temperature of the temperature sensor S section becomes the target achievement temperature C.
When it becomes 1 or more, the process moves to step s11 and temperature control is performed to the final maximum target temperature D1. At this time, the temperature inside the kotatsu is as shown in E1.

Next, the temperature control flowchart shown in FIG. 8 for the case where the target temperature is set to intermediate target temperature 4 will be explained.
The explanation will be as follows. When the power switch 4 is turned on to start energizing the heater H, the first control section 9 determines the intermediate target temperature in step e1 based on the detected temperature G2 of the temperature sensor S shown in FIG. First, it is determined whether A2 has been reached among the target achieved temperatures A2, C2, and D2, and at the same time, in step e2, it is determined whether 15 minutes have elapsed since the start of energization to the heater H. Based on this judgment, if the detected temperature G2 of the temperature sensor S is lower than the target achieved temperature A2 and the elapsed time is within 15 minutes, the energization rate to the heater H is set to 100%. After this, when the detected temperature G2 of the temperature sensor S section becomes equal to or higher than the target achieved temperature A2, or when more than 15 minutes have elapsed, steps e4 and e5 are performed.
When the target temperature is below C2 and the time has passed.
Determine if it is within 30 minutes. Based on this judgment, if the time elapsed is less than the target achieved temperature C2 and the elapsed time is less than 30 minutes, the energization rate to the heater H is changed to 50% as shown in FIG. Then, when the detected temperature G2 of the temperature sensor S section becomes equal to or higher than the target achieved temperature C2 within 30 minutes, the process moves to step e7 and the temperature is controlled to the final intermediate target temperature D2. The temperature inside the kotatsu at this time is as shown in 2.

In this way, in the above embodiment, the heater H
At the start of energization, the heater H is fully energized, and then the temperature detected by the temperature sensor S is compared with the target achieved temperature, and the elapse of the energization time is determined, and the heaters are sequentially energized.
Since the current conduction rate to the kotatsu H is configured to decrease according to each target temperature, the internal temperatures E1 and E of the kotatsu for each target temperature at the time of startup are shown in FIG.
2...En rises faster and almost matches the optimum temperature changes K1, K2...Kn in the kotatsu, improving the temperature characteristics in the kotatsu at the time of startup. In particular, it is possible to improve the rise in temperature inside the kotatsu when setting a temperature other than the maximum target temperature.

Furthermore, the above-mentioned electric kotatsu has the following effects.

Since the control states are mutually monitored between the first and second control units 9 and 10, one of the control units 9 and 1
0 becomes inoperable due to a failure, the power supply to the heater H can be immediately stopped through the protection circuit 12. This makes it possible to prevent melting of the temperature fuse and fires caused by overheating.

Since the phase control is triggered at the zero cross position, the noise level due to the firing can be reduced. In other words, the noise level increases if the voltage is turned on at a high voltage level position.

Since the rotation speed of the fan motor M is switched in two steps, the rotation speed of the fan motor M can be reduced when the temperature inside the kotatsu is stabilized, thereby reducing noise and vibration.

Since the protection circuit is provided, disconnection and short circuit of the temperature sensor S and overheating of the heater H can be prevented.

Note that the present invention is not limited to the above-mentioned embodiment, and may be modified without departing from the spirit thereof. For example, the protection circuit may have the configuration shown in FIG. Note that the same parts as in FIG. 5 are given the same reference numerals. Here, the output terminal of each comparator 22, 23 constituting the abnormality detection circuit 30 is connected to the PNP type transistor Q1 of the gate pulse generation circuit 31.
0 via a resistor R10. The emitter of this transistor Q10 is connected to the gate of a thyristor Q10 in the cutoff holding circuit 32 via a resistor R11, and the anode of this thyristor Q11 is connected to the NPN type transistor Q12 in the cutoff circuit 33 via a resistor R12. is connected to the base of the

Therefore, since the output level of each comparator 22, 23 is normally at a high level, the transistor Q10 is in a non-conducting state and the thyristor Q11 is also in a non-conducting state. As a result, the transistor Q12 of the cutoff circuit 33 becomes conductive, and a heater control signal is sent through the transistor Q4 and the resistor R5. Here, for example, when the heater H overheats and the output level of the comparator 23 becomes low level, the transistor Q10 becomes conductive, and a gate pulse is generated from the gate pulse generation circuit 31 to the gate of the thyristor Q11. is applied to
Thus, thyristor Q11 becomes conductive and transistor Q12 becomes non-conductive. As a result, the transmission of the heater control signal is cut off, and the power supply to the heater H is stopped.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide an electric kotatsu that improves the rise characteristics of the temperature inside the kotatsu and provides an optimal temperature inside the kotatsu.

[Brief explanation of the drawing]

Figures 1 to 3 are configuration diagrams showing one embodiment of the electric kotatsu according to the present invention, in which Figure 1 is a specific configuration diagram, Figure 2 is an external view of the tower, and Figure 3 is a control diagram. - External view of La, Figures 4A to 4E
The figure is an explanatory diagram of phase control, Figure 5 is a specific circuit diagram of the protection circuit, Figure 6 is a temperature control flowchart of the electric kotatsu of the present invention, and Figure 7 is the temperature control of the electric kotatsu of the present invention. 8 is a temperature control flowchart of the electric kotatsu of the present invention; FIG. 9 is a diagram showing the temperature control results of the electric kotatsu of the present invention; FIG. 10 is a diagram showing a modification of the protection circuit; FIG. 11 is a diagram for explaining temperature control of a conventional electric kotatsu. DESCRIPTION OF SYMBOLS 1... Controller, 7... Tower, 9... First control section, 10... Second control section, 11, 13... Triack, 12... Protection circuit, 14... Zero cross detection circuit, 15, 18... Clock circuit, 16... Display circuit, 17...setting switch, S...temperature sensor, H...
Heater, M...Fan motor.

Claims (1)

[Scope of utility model registration request] Temperature sensors installed on the ceiling of the tower, each target temperature determined according to the optimal temperature change to reach each target temperature, and the energization time determined for each target temperature. is set, and when the heater installed on the ceiling of the tower starts to be energized, the heater is fully energized, and then the temperature detected by the temperature sensor is compared with the target achieved temperature. and a temperature control section that determines the elapse of the energization time and sequentially reduces the energization rate to the heater in accordance with the target achieved temperature to control the temperature to the target temperature. Kotatsu.