JPH0612688B2 - Heater control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a temperature control means for a large area heating element such as an electric carpet.

(Background Art) A heating device such as an electric carpet obtains a feeling of heating by low-temperature radiation and heat transfer to a sitting person, and it is necessary to have a large area, but in recent years, it has been used from the viewpoint of energy saving. The heating area is switched according to the number of people who use it, and in the case of a small number of people, the method of using it in a small area is becoming popular. Behind this, besides saving energy, electric carpets are often used in combination with other heaters, such as oil stoves, so that the radiant heating feeling as a main heating device and the ability to raise the room temperature do not pose a problem. It seems that there are many people.

Therefore, as a function required for a heating device such as an electric carpet, when it is used by one person, it is possible to raise the room temperature from the heating that emphasizes the contact heat transfer that can heat only the sitting part of the person. It is a function that allows you to freely choose how to heat up to heating that can heat a large area like when used by many people.

(Object of the Invention) The present invention has been proposed in view of the above points, and the heat generation area can be freely selected.

Although the heat generating block is divided into a plurality of blocks, the number of temperature sensors is smaller than the number of heat generating blocks, which simplifies the wiring work and simplifies the control circuit.

Part of the heating block divided into multiple blocks that generates heat even if the heating area selection switch is turned on, even if a portion of the circuit where the heating line is disconnected and does not warm up occurs There is no abnormal heat generation.

Simplify the structure of the heating area selection switch.

Even if the heating area is switched, the heat generation control temperature can be kept substantially the same.

It is an object of the present invention to provide a heater control device having functions such as.

DISCLOSURE OF THE INVENTION The present invention will be described in detail below with reference to the drawings illustrating embodiments.

FIG. 1 is a perspective view of an electric carpet to which the heater control device of the present invention is applied. In the figure, 1 is an electric carpet body, 2 is a temperature control circuit section, 3 is a power cord section, and H _{1 to} H ₆
Is an individual heater element divided into six, SE is the heater element
_One temperature detecting element for detecting the heat generation temperature of H ₁ ~ H ₆ , S ₁ ~
S ₆ is a heating area selection switch for turning on / off the power supply to each of the 6 divided heater elements H _{1 to} H ₆ . Needless to say, the number of divided heater elements is not limited to six.

FIG. 2 shows a heater control device of the embodiment shown in FIG. Explaining the configuration in the figure, commercial power supply
The heater elements H _{1 to} H ₆ divided into 6 from the AC via the power switch SW and the relay contact Rys are heating area selection switches S _{1 to} S _6.
A current converter CT is provided at a position where the sum of the energization currents to the heater elements H _{1 to} H ₆ flows in parallel with each other. Further, one temperature detecting element SE formed from the temperature detecting wires 4, 4'and the negative characteristic heat sensitive resin 5 is the heater element H ₁
It is installed so as to be adjacent to H ₆ .

On the other hand, a comparison circuit 7 for performing temperature control by comparing the magnitude of the temperature signal of the temperature detection element SE with a reference voltage, and this comparison circuit 7
Including a switching circuit A for turning on / off the relay contact Rys according to the comparison result, and a heat generation area determination circuit 8 for generating a reference voltage corresponding to the heat generation area from the output of the current converter CT and giving it to the comparison circuit 7. Power supply circuit 6 for supplying power to the circuit
And are provided.

Then, the operation of the above temperature control circuit is as follows. That is, when the temperature of the heater elements H _{1 to} H ₆ rises, the impedance of the negative characteristic thermosensitive resin 5 of the temperature detecting element SE decreases, and a constant voltage applied from the power supply circuit 6 is generated by the temperature detecting element SE and the resistor R ₂ . The temperature voltage V ₂ obtained by rectifying and smoothing with the divided diode D ₂ and capacitor C ₂ increases. On the other hand, the sum of the currents flowing in the heater elements that are turned on among the heating area selection switches S _{1 to} S ₆ is detected by the current converter CT, and the output of the current converter CT is rectified by the diode D ₁ and the capacitor C _1. It is smoothed to become the heating area voltage V ₁ , and is given to the comparison circuit 7 via the heating area determination circuit 8 as the reference voltage V ₀ according to the heating area.

The reference voltage V ₀ and the temperature voltage V ₂ are compared by the comparison circuit 7 that constitutes the preceding stage of the switching circuit A. When the temperature voltage V ₂ exceeds the reference voltage V ₀ , the comparison circuit 7 causes the temperature setting range up to that point. Switching circuit A kept on
A relay connected in series with this transistor Q is inverted by inverting the transistor Q that forms the latter stage of the transistor.
Stop the drive of the Rys excitation coil, and open the relay contact Rys
Is turned off from the previous on-state to the off-state to cut off the power supply path to the heater elements H _{1 to} H ₆ . Further, when the temperature drops due to the interruption of the power supply to the heater elements H _{1 to} H ₆ , the temperature voltage V ₂ becomes lower than the reference voltage V ₀ , and the comparison circuit 7
The output of the heater element H ₁
~ H ₆ will be maintained at a predetermined temperature.

The temperature voltage V ₂ obtained from the temperature detection element SE is proportional to the total area of the heater elements that are changing in accordance with the temperature and generating heat, and even if the temperature is the same, the heating area selection switch S ₁
Although the value changes depending on the state of ~ S _6, the reference voltage V ₀ obtained from the current converter CT through the heat generation area determination circuit 8 changes according to the area of the heater element that is generating heat. , The reference voltage V ₀ changes at the same rate as the temperature voltage V _2, and the selection state of the heater element becomes irrelevant in the comparison of both.

That is, the temperature detecting element SE is one for the heater elements H _{1 to} H ₆ , and if there is one of the heating area selection switches S _{1 to} S ₆ that is turned off, the temperature rise of that portion will not occur. Since the temperature voltage disappears, the reference voltage value V ₀ to the switching circuit A must be changed according to the size of the heat generation area as in the present invention. There is a risk that the switching circuit will not operate until the temperature is compensated, that is, until the temperature of the heat generating portion becomes high, and the abnormal temperature rises.

It is also possible to create the reference voltage directly from the state of the heating area selection switches S _{1 to} S ₆ , but in that case, even if the heating area selection switch is turned on, the heater element is disconnected. If there is, the temperature voltage and the reference voltage become unbalanced and abnormal heat generation occurs. However, in the present invention, the sum of the currents supplied to the heater element is detected by the current converter CT to obtain the reference voltage corresponding to the substantial heat generation area, and therefore the above-mentioned inconvenience does not occur. In addition,
Since the heating area selection switches S _{1 to} S ₆ need only be able to be turned on / off, there is an advantage that the mechanical structure is simple.

In the above embodiment, one heater is used for six heater elements, but the number of heater elements can be increased if the number of heater elements is large.

In addition, the current converter CT
Although the case has been described above where the detection is performed by the above method, other methods may be used and the detection method is not limited thereto.

(Effects of the Invention) As described above, in the present invention, a heating element is formed by facing a heater element divided into a plurality and a common temperature detecting element that detects a heat generation temperature of the heater element, Since a comparison circuit for comparing the signal according to the current flowing through the heater element and the temperature signal detected by the temperature detection element is provided, the energization to the heater element is controlled by the signal from the comparison circuit. (B) The divided heater elements can be selectively energized to freely select the heat generation area.

(B) Although the heating heater is divided into a plurality of pieces, the number of temperature detecting elements is smaller than the number of divisions of the heater elements, so wiring work is simple and the control circuit is simple.

(C) Since the reference value for temperature control is changed according to the actual heating area, the heating of a part of the circuit in which the heating area selection switch is on among the plurality of divided heater elements Even if there is a part where the wire is broken and does not warm up, the temperature of the part that is turned on and generating heat does not abnormally generate heat.

(D) Since the heating area selection switch only needs to be turned on / off, the structure can be simplified.

(E) Since the reference value for temperature control is changed according to the heating area, the heating control temperature can be kept substantially the same even if the heating area is switched.

And so on.

[Brief description of drawings]

FIG. 1 is a perspective view of an electric carpet to which the present invention is applied, and FIG. 2 is a circuit configuration diagram of the same. 1 ... Electric carpet body, 2 ... Temperature control circuit section, 3
...... Power cord part, 4, 4 '... Temperature detection line, 5 ... Negative characteristic heat sensitive resin, 6 ... Power circuit, 7 ... Comparison circuit, 8 ...
… Heat generation area determination circuit, A… Switching circuit, H _{1 to} H ₆
...... Heater element, SE …… Temperature detection element, S _{1 to} S ₆ …… Heating area selection switch, CT …… Current converter, AC …… Commercial power supply, SW …… Power switch, Rys …… Relay contact

Claims (2)

[Claims] 1. A heating element is formed by facing a heater element divided into a plurality of parts and a common temperature detecting element for detecting a heat generation temperature of the heater element, and a signal corresponding to a current flowing through the heater element is formed. A heater control device comprising a comparison circuit for comparing a temperature signal detected by the temperature detection element, and controlling the energization of the heater element by a signal from the comparison circuit. 2. The heater control device according to claim 1, wherein the current flowing through the heater element is detected by a current converter.