JPH0426193B2 - - Google Patents

Description

TECHNICAL FIELD The present invention relates to electric heating devices such as electric carpets.

(Background Art) There are various methods for on-off control of electric heating devices such as electric carpets, but there is one method for temperature control that uses the current flowing from the commercial power supply applied to the heater to the temperature sensor as a temperature signal. teeth,
Since the temperature signal disappears when power to the heater stops, temperature management during off operation (transition from on state to off state) is controlled based on temperature information from the temperature sensor, and when on operation (off state The operation of transitioning from to to on state) is generally controlled for a fixed period of time by a timer.

In other words, when the heater temperature of an electric heating device such as an electric carpet reaches the set temperature, a signal is issued to stop the power supply to the heater, and at the same time, the timer starts counting and the timer starts counting, and the timer starts counting. When the time has elapsed, an on-off signal is issued and energization to the heater is started.

FIG. 5 shows the configuration of a temperature control circuit for a conventional electric heating device including a timer circuit as described above, and TIM' is the timer circuit. In the figure, the temperature signal is divided to a predetermined value by resistors R ₉ ′, R ₈ ′, and variable resistor VR ′, and then sent to a comparator.
A comparison is made with a predetermined value by CP ₁ ′, and the output of the comparator CP ₁ ′ drives the transistor Tr ₁ ′, energizes the relay Ry′ connected to its collector circuit, and connects the commercial power supply AC′ and the heater H. It is designed to turn on and off the relay contact ry connected between
Note that the set temperature is changed by adjusting the variable resistor VR'.

Furthermore, the timer circuit TIM′ is provided between the DC power supply V _CC ′ and the output terminal of the comparator CP ₁ ′.
When the output of the comparator CP ₁ ′ becomes low level, that is, when the power supply to the heater H′ is stopped, power is applied and operation starts, and after a predetermined time, the programmable union transistor PUT′ When conduction occurs, the comparator CP ₁ ′ is inverted via the resistor R ₆ ′, and the current supply to the heater H′ is restarted.

By the way, in the conventional circuit shown in FIG. 5, the set time of the timer circuit TIM' for counting the off time was constant regardless of the set temperature. As an example, Fig. 6 shows the temporal change in temperature during temperature control of an electric carpet when the off time is set to 2 minutes. Off time t Temperature range cooled during _OFF (difference between energization on and off in carpet surface temperature; on-off width)
ΔT ₁ is large, and when the carpet surface temperature is low as in β, the temperature range ΔT ₂ that is cooled within the set off time t _OFF becomes small. That is, even if the off time is constant, the on-off width varies depending on the set temperature, resulting in a disadvantage that the heating sensation is poor.

One way to solve this problem is to shorten the set off time, but this increases the frequency of on-off switching and causes problems with the lifespan of contacts such as relays that control energization of the heater, so it is not recommended to shorten the off time extremely. I couldn't even do it.

(Object of the Invention) The present invention has been proposed in view of the above points, and its purpose is to reduce the off time from when power to the heater is stopped until power is restarted to the heater. By varying the on-time of energization, the temperature range is made almost uniform,
An object of the present invention is to provide an electric heating device that can perform comfortable temperature control.

(Disclosure of the Invention) An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 is a circuit diagram showing one embodiment of a temperature control circuit for an electric heating device of the present invention. 1st
In the figure, H is a heater unit, _one end of which is connected to a commercial power source AC via a relay contact ry, and the other end via a power switch _SW1 . In addition, the temperature detection electrode of heater unit H
One end of S ₁ is connected to the other end of heater H ₁ , and the other end of temperature detection electrode S ₁ is connected to temperature detection section 1 . In addition, Fig. 2 shows the heater unit H.
Examples of configurations are shown, in which (a) to (c) are examples configured in a planar shape, and (d) is an example configured in a wire shape. In Figure 2, H ₁ is a heater, S ₁ is a temperature detection electrode, Z is a temperature sensor material with negative temperature-impedance characteristics such as an organic semiconductor, a is a reflective electrode, b is a core material, and c is an insulating coating. .

Returning to FIG. 1 and explaining the other configuration, the temperature detection section 1 has resistors R ₁ and R ₂ connected in parallel with the heater H ₁ .
A temperature detection electrode _S1 is connected to a connection point between resistors _R1 and _R2 , and this connection point is connected to an inverting input terminal of an operational amplifier _OP1 via a resistor _R3 . Further, the non-inverting input terminal of the operational amplifier _OP1 is connected to the other end of the heater H via a resistor _R5 , and is also connected to its own output terminal via a resistor _R4 . The anode of a diode D ₁ is connected to the output terminal of the operational amplifier OP ₁ , and its cathode is connected to the other end of the heater H ₁ via a capacitor C ₁ and a resistor R ₆ .
It is connected to the control section 2 as an output.

However, when heater _H1 is energized,
A voltage is generated in the temperature detection electrode S ₁ by the current flowing from the heater H ₁ through the temperature sensor material Z, and this voltage is amplified by the operational amplifier OP ₁ and then connected to the diode.
D ₁ is rectified by the capacitor C ₁ and input to the control unit 2 as a temperature signal indicating the heater temperature.

Next, the control unit 2 uses the microcomputer M ₁
is the main component, and the temperature signal indicating the heater temperature, which is the output of the temperature detection section 1, is input to the input terminal.
S ₁₁ is now being entered. In addition, an input terminal S 12 is provided to input a set temperature signal corresponding to the set temperature adjusted by the user, and a variable resistor VR ₁ whose both ends are connected between the DC power supply V ₂ and the circuit ground is connected to the input terminal S ₁₂ . Terminals are connected. The details of the function and operation of microcomputer _M1 will be described later, but the heater temperature based on the temperature signal and the set temperature based on the set temperature signal are compared, and when the heater temperature becomes higher than the set temperature, heater _H1 In addition to the basic function of stopping the energization to the heater H ₁ and restarting the energization to the heater H ₁ by time control after the energization to the heater H 1 has stopped, the main part of the present invention is to Yes, heater H ₁ before power supply to heater H ₁ is stopped.
A means for counting the energization time to the heater H 1 and a means for changing the time from when the energization to the heater H ₁ is stopped to when the energization to the heater H ₁ is restarted according to the counted energization time are implemented by software. has been realized. Note that the signal that controls the energization of the heater _H1 is output from the output terminal _S01 , and is output from the relay drive unit 3.
It is beginning to be given to Note that V _DD ,
V _SS is a power supply terminal, and X ₁ and X ₂ are terminals for externally connected resistor R ₇ .

Next, the relay drive unit 3 has a transistor Q ₁ connected to the output terminal S ₀₁ of the microcomputer M ₁ via a resistor R ₈ , and the relay coil of the relay Ry is inserted into the collector circuit of the transistor Q 1 . Note that _D2 is a diode for absorbing surges generated in the relay coil.

Figure 3 shows the functional parts inside the microcomputer _M1 , which digitizes the temperature signal voltage V _A and temperature setting voltage V _B input from the input terminals S ₁₁ and S ₁₂ , and supplies the DC power supply V _DD. A/D converters 11, 12, A/D converters 11,
a comparison unit 13 that outputs a signal to control the relay drive unit 3 from the output terminal S ₀₁ so as to stop energizing the heater H ₁ when the heater temperature becomes higher than the set temperature; An on-time counting section 14 that counts the time during which electricity is on to the heater _H1 ; an off-time setting section 15 that sets an off time according to the count value of the on-time counting section ₁₄ ; It is composed of an off holding section 16 that keeps the power to the heater _H1 off for the off time set by the off time setting section 15 after the power is turned off, and restarts the power supply to the heater _H1 after the off time has elapsed. has been done.

FIG. 4 is a flowchart showing the operation of the microcomputer _M1 related to temperature control in the above embodiment. After initial settings are made in step, the output terminal _S01 is set to high level to turn on the relay Ry. In the step, the temperature setting voltage V _B corresponding to the state of the variable resistor VR ₁ is read, and A/D converter 12 converts it into a digital signal to obtain the temperature setting value D _A2 . Also, in the step, the temperature signal voltage V _A is read and A/
The D converter 11 performs A/D conversion to obtain a temperature signal value D _A1 . Further, in the step, the on-time counting section 14 counts the on-time _T1 .

Next, in step, the comparison section 13 compares the temperature set value D _A2 and the temperature signal value D _A1 to determine that D _A2 >
If D _A1 (the heater temperature is lower than the set temperature), proceed to step, and if D _A2 ≦ D _A1 (the heater temperature is equal to or higher than the set temperature), proceed to step and set output terminal S ₀₁ to low level and turn on relay Ry. Turn it off. Next, in step, the off time setting section ₁ is set according to the on time T1 during which the heater _H1 was energized.
5, if the on time _T1 is, for example, 70 seconds or more, the heater off holding time T is set to, for example, 80 seconds, and if the on time _T1 is 70 seconds or less, the value obtained by subtracting the on time _T1 from, for example, 150 seconds, That is, T=150−T ₁
is the setting for the heater-off holding time T. Then,
In the step, the off time _T2 is counted. Then, when the off time _T2 reaches the set heater off holding time T in the step, the process returns to the step and energization to the heater _H1 is resumed.

As an example, when the on-time _T1 to heater _H1 is 50 seconds, the heater-off holding time T is 150-50=
Set at 100 seconds, on time T ₁ to heater H ₁ is 70
The heater-off holding time T when the temperature is 150-70 seconds
= set at 80 seconds. Furthermore, when the on-time T ₁ to the heater H ₁ is 200 seconds, the heater-off holding time T is 80 seconds.

In other words, even if the set temperature of heater H ₁ is constant, the on time T ₁ of heater H ₁ will not be constant depending on the usage conditions. For example, when considering differences in ambient temperature as usage environmental conditions, when the ambient temperature is low, the heater _H1
In the present invention, when the on time T ₁ becomes large, _the heater off holding time T is automatically set to be short, so that the decrease in the surface temperature of the electric heating device is small. . Also, when the ambient temperature is high, the on time T ₁ to heater H ₁ becomes small,
Although the heater-off holding time T is set long, the decrease in surface temperature is small because the ambient temperature is high. Therefore, the temperature range of control becomes approximately constant depending on the ambient temperature, and comfort can be improved. In addition,
There is an advantage that the number of openings and closings of contacts such as relays that control energization to the heater _H1 can be kept small.

In addition, although specific numerical values were shown in the above-mentioned Example, each numerical value can be changed suitably.

(Effects of the Invention) As described above, in the present invention, when the heater temperature becomes higher than the set temperature, the power supply from the power supply to the heater is stopped, and after a predetermined time after the power supply is stopped, the power supply is transferred from the power supply to the heater. An electric heating device that restarts energization of the heater, comprising: means for counting the energization time until the energization to the heater is stopped; means for setting an off time according to the counted energization time; Since the heater is provided with a means for maintaining the energization stop to the heater until the time counted from the time of stopping exceeds the OFF time, the energization stop time changes depending on the surrounding environment, so that the energization stop time changes depending on the surrounding environment. This reduces the temperature difference between the two and provides comfortable heating.

[Brief explanation of drawings]

Fig. 1 is a circuit configuration diagram showing an example of the temperature control circuit of the electric heating device of the present invention, Fig. 2 is a diagram showing an example of the configuration of the heater unit, and Fig. 3 is the configuration of functional parts in the microcomputer. 4 is a flowchart showing the operation of the microcomputer, FIG. 5 is a circuit configuration diagram of a temperature control circuit in a conventional electric heating device, and FIG. 6 is a diagram showing the state of temperature control. H...Heater unit, _H1 ...Heater, _S1 ...
...Temperature detection electrode, Z...Temperature sensor material, AC...
Commercial power supply, Ry...relay, ry...relay contact,
1...Temperature detection section, 2...Control section, 3...Relay drive section, _M1 ...Microcomputer.

Claims (1)

[Scope of Claims] 1. In an electric heating device that stops energizing the heater from a power source when the heater temperature becomes higher than a set temperature, and restarts energizing the heater from the power source after a predetermined period of time after the energization stops. , means for counting the energization time until the energization to the heater is stopped; means for setting an off time according to the counted energization time; An electric heating device comprising: means for keeping energization to the heater stopped until an off time is exceeded. 2. The electric heating according to claim 1, wherein when the energization time to the heater exceeds a predetermined value, the time from when the energization to the heater is stopped to when the energization to the heater is restarted is constant. Device. 3. The electric heating device according to claim 1 or 2, wherein the sum of the energization time to the heater and the time from when the energization to the heater is stopped until the energization to the heater is restarted is constant. .