JPH07271454A - Temperature controller - Google Patents

Abstract

PURPOSE:To provide the temperature controller for a planar thermosensitive heating element with which the change of the set temperature of the thermosensitive heating element can be reduced even when the voltage of a commercial power source is fluctuated. CONSTITUTION:This temp. controller is equipped with a planar thermosensitive heating element 1 arranged with a thermosensitive heating wire 5 provided with a heating wire 2 to be heated by energization and a detecting line 3, deciding means 14 for outputting a signal corresponding to the level of a voltage VTC generated between both terminals of the detecting line by an AC current flowing from the heating wire through the thermosensitive member to the detecting line, and relay driving circuit 19 for controlling the energization of the heating wire corresponding to the signal of the deciding means. This device is also provided with a reference voltage setting means 10 for outputting a reference voltage VS corresponding to the fluctuation of a power supply voltage. The deciding means is provided with a comparator circuit 17 for inputting a voltage VDC obtd. by rectifying and smoothing the voltage VTC, and the voltage VS and outputting a signal to control the relay driving circuit through comparison of those input voltages.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control device for a sheet heating device mainly used for floor heating devices such as electric carpets and electric floor heaters.

[0002]

2. Description of the Related Art Since a surface warming tool such as an electric carpet consumes a relatively large amount of power, temperature control has been conventionally performed in Japanese Patent Laid-Open No.
As shown in Japanese Laid-Open Patent Publication No. 2-19917, on / off control using a relay is generally used.
The principle is as follows.

As shown in FIG. 5, when the commercial power supply 7 is energized,
Heat generation line 2 consisting of a line that heats up
The sensing line 3 that has a negative impedance
Formed by facing each other with an organic heat-sensitive member 4
Wire-shaped heat-sensitive heating wires 5 are arranged in a zigzag shape.
The sheet-like heat-sensitive heating element 1 and the heat-generating wire 2 at one end of the heat-sensitive heating wire 5
Short the detection line 3 and the heat generation line 2 through the heat sensitive member 4.
Both ends of sensing line 3 due to the alternating current flowing into sensing line 3
Temperature-AC voltage characteristic voltage (hereinafter V _TCStands for
You (See Fig. 6) is used to determine the temperature rise of heating line 2.
Detected by means 14, if there is a temperature rise to the set temperature,
Turn off the relay contact 19a of the relay drive circuit 19 to stop heat generation.
Stop, and if the temperature of the heating wire 2 drops, relay contact 19
Controlling the temperature constant by turning on a to generate heat
To do. Also, to obtain the desired temperature, set
The constant temperature was made variable.

[0004]

However [0005] In the temperature control device using a V _TC generated between such a detection line 3 of the thermal heating wire 5 at both ends, when it reaches the value V _TC is preset , Turn off the relay contact 19a, and
The power supply to 2 is stopped, and V _TC is the heating wire.
Since it is expressed as a function of the voltage of the commercial power supply 7 energized to 2, the impedance of the heat-sensitive member 4 and the resistance value of the detection line 3,
If the voltage of the commercial power supply 7 fluctuates, the V _TC generated at both ends of the detection line 3 will be affected.

As shown in FIG. 7, the voltage of the commercial power source 7 is low.
V when changing at the same temperature, when viewed at the same temperature_TC
Also falls at the same rate as the rate of decrease in the voltage of commercial power supply 7.
This is V_TCIs reached in advance, the
Turn off the relay contact 19a to stop the power supply to the heating wire 2.
In the temperature control method,
The lower the voltage, the higher the set temperature. Was
For example, when the commercial power supply 7 is 100V in FIG.
If the temperature of the heat generation line 5 reaches 72 ° C, turn on the relay contact 19a.
Set to turn off and stop energizing heating line 2
If it says, V _TCRelay contact when the voltage reaches 870 mV
It turns off 19a. However, other than commercial power supply 7
The commercial power supply 7
If the voltage of V drops to 80V, V_TCTo 870 mV
The temperature reached is 74.5 ° C. In such a case,
Relay contact 19a until the temperature of heating wire 5 reaches 74.5 ° C
Does not turn off.

In the temperature control as described above, the temperature of the entire surface of the sheet-shaped heat-sensitive heating element 1 can be controlled to be constant only when nothing is placed on the entire surface of the sheet-shaped heat-sensitive heating element 1. Usually, a heat insulating material such as a cushion is often placed on the electric carpet or floor heating panel. The temperature sensor is configured to detect the average temperature, but since the temperature sensor is configured to generate a temperature distribution, the temperature sensor has a temperature-impedance characteristic shown in FIG. If the temperature is uniform on the entire surface, the temperature is controlled at the temperature point A, but if the high temperature point B occurs due to partial heat insulation, etc., the impedance at the point C will be the same as that at the point A. The surface (non-insulated surface) is controlled. Therefore, the maximum temperature of the heat-sensitive heating wire 5 that constitutes the sheet-shaped heat-sensitive heating element 1 is the point where the temperature becomes high due to partial heat insulation, etc., and the temperature of this part exceeds the heat-resistant limit temperature of the heat-sensitive member 4 etc. Need not to.

Heat-sensitive heating wire 5 (36 m) wiring 40 m
In an electric carpet set to form a 900 mm x 1800 mm sheet-shaped heat-sensitive heating element 1 in a zigzag pattern at m and obtain a heat generation amount of 300 W when AC 100 V is applied to the heating wire 2, 300 mm x 300 mm
Fig. 9 shows the relationship between the set temperature and the maximum temperature of the heat-sensitive heating wire 5 when the urethane foam heat insulating material is placed on the surface.
It can be seen that when the set temperature is increased by 1 ° C, the maximum temperature is increased by approximately 3 ° C. Commercial power supply 7 voltage is 100V
When the voltage drops from 80V to 80V, the set temperature of the heat-sensitive heating wire 5 increases from 72 ℃ to 74.5 ℃ by 2.5 ℃, so the maximum temperature increases by 7.5 ℃, and If the set temperature is set so as to be close to the limit temperature, it is dangerous because the maximum temperature easily exceeds the limit temperature due to the voltage drop of the commercial power supply 7.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a sheet-like heat-sensitive heating element capable of reducing the change in the set temperature of the heat-sensitive heating wire even when the voltage of the commercial power source fluctuates. To provide a temperature control device of.

[0009]

In order to solve such a problem, a temperature control device according to a first aspect of the present invention includes a heating line formed of a line that generates heat when a commercial power source is energized, and a detection line formed of a conductor line. , A planar heat-sensitive heating element having a heat-sensitive heating wire formed correspondingly via an organic heat-sensitive member whose impedance changes negatively according to temperature, and a heating wire at one end of the heat-sensitive heating wire. And the detection line are short-circuited to form a circuit ground, and a signal is generated according to the magnitude of the temperature / AC voltage characteristic voltage V _TC generated between both ends of the detection line by the AC current flowing from the heat generation line to the detection line through the heat-sensitive member. In a temperature control device comprising: a determination unit that outputs, and a relay drive circuit that receives a signal from the determination unit and controls energization of a heating wire,
Together in response to variations in the voltage of the commercial power source providing a reference voltage setting means for outputting a reference DC voltage V _S is set to an arbitrary voltage, the determination unit rectifies the temperature-AC voltage characteristic voltage V _TC, smooth Temperature / DC voltage characteristic voltage V _DC
The reference DC voltage V _S is input, and a comparator circuit is provided which outputs a signal for turning on / off the relay drive circuit by comparing the temperature / DC voltage characteristic voltage V _DC with the reference DC voltage V _S.

According to a second aspect of the present invention, in the temperature control apparatus according to the first aspect, the reference voltage setting means generates a DC voltage V _DCIN that fluctuates at substantially the same rate as the fluctuation rate of the commercial power supply voltage. Commercial power supply voltage reading circuit to output,
_Reference DC voltage V _obtained by amplifying DC voltage V _DCIN with an operational amplifier
_And a reference DC voltage setting circuit that outputs _S.

According to a third aspect of the present invention, in the temperature control apparatus according to the first aspect, the reference voltage setting means includes a diode, an impedance element and a constant current diode in series with a commercial power source. The reference DC voltage V is provided by smoothing the voltage generated between both ends of the constant current diode.
It is configured to output _S.

[0012]

According to the structure of claim 1, the reference DC voltage V _S is reduced to an arbitrary voltage corresponding to the rate of decrease of the voltage of the commercial power source, so that the voltage of the commercial power source is other high capacity power equipment. Even if it is lowered due to the combined use of etc., the maximum temperature of the heat-sensitive heating wire does not rise, it is possible not to exceed the heat-resistant limit temperature of the heat-sensitive member, and since the preset temperature of the heat-sensitive heating wire can be raised in advance, It is possible to provide a surface heating tool with high heating capacity.

According to the second aspect of the present invention, the reference DC voltage V _S is output by the commercial power supply voltage reading circuit and the reference DC voltage setting circuit, which further promotes the operation of the first aspect. be able to.

According to the third aspect of the present invention, in addition to the effect of the first aspect, the reference DC voltage V _S can be output with a small number of parts, so that the circuit becomes compact.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram of a temperature control device, and FIG. 2 is a perspective view of a heat-sensitive heating wire described later. Members having the same basic functions as those described in the conventional example are designated by the same reference numerals.

Reference numeral 1 denotes a sheet-like heat-sensitive heating element, which is formed in a flexible and substantially flat plate shape having a member that generates heat when energized, and is laid on a floor or the like to perform floor heating and the like. The sheet-shaped heat-sensitive heating element 1 includes a heating wire 2, a sensing wire 3,
A wire-shaped heat-sensitive heating wire 5 having the heat-sensitive member 4 as a main constituent member is arranged inside in a zigzag shape.

The heat generating line 2 is a line that generates heat with energization, and is connected in series with a commercial power supply 7 (AC 100 V) via a relay contact of a relay drive circuit described later and a power switch 6.

The detection line 3 is composed of a conductor line, and is arranged around the heat generation line 2 so as to face each other via an organic heat sensitive member 4 whose impedance changes negatively according to the temperature, as shown in FIG. Is installed, and the coating around the sensing line 3 is provided 8
By doing so, a wire-shaped heat-sensitive heating wire 5 is formed. Further, one end of the detection line 3 is connected to one end of the heating line 2 corresponding to the ground side of the temperature control device, and the other end is connected to the commercial power supply line via the bias circuit 9.

Reference numeral 10 is a reference voltage setting means, which is a commercial power supply 7
It outputs a reference DC voltage (hereinafter abbreviated as V _S ) which is set to an arbitrary voltage corresponding to the fluctuation of the voltage, and has a commercial power supply voltage reading circuit 11 and a reference DC voltage setting circuit 12. ing.

The commercial power supply voltage reading circuit 11 is a commercial power supply.
DC voltage (hereinafter V
_DCIN ) is output. Specifically, the commercial power supply voltage reading circuit 11 includes a diode D as shown in FIG.
1 and the resistors R1 and R2 are connected in series to the commercial power source 7 so as to form a series circuit, and the capacitor C1 is connected to the resistor R2.
One end is connected to the connection point of the resistors R1 and R2, and the other end is connected to the ground so as to be connected in parallel with. Therefore, the voltage V _{AC of the} commercial power source becomes a half-wave pulsating current due to the diode D1, and is further divided by the resistors R1 and R2.
By being smoothed by the capacitor C1, V _AC
V _DCIN, which fluctuates at the same rate as the fluctuation ratio of R, is generated between both terminals of the resistor R2. Further, the relationship between V _DCIN and V _AC is as follows.

V _DCIN = R2 / (R1 + R2) × V _AC × 2 ^{1/2 The} reference DC voltage setting circuit 12 varies at a rate different from the rate of variation of V _{DC IN} by amplifying V _DCIN with an operational amplifier. V _S is generated and input to a comparator circuit described later. In the reference DC voltage setting circuit 12, as shown in FIG. 3, V _DCIN is input to the non-inverting input terminal of the operational amplifier OP. A resistor R4 is connected between the inverting input terminal and the output terminal of the operational amplifier OP, a resistor R5 is connected between the inverting input terminal and the ground, and the commercial power supply 7 is connected.
A resistor R3 is connected between the output terminal and the inverting input terminal of the power supply circuit 13 connected in series. The _relationship between the input voltage V _DCIN , the output voltage V _ZD of the power supply circuit 13, and the output voltage V _S of the reference DC voltage setting circuit 12 is as follows.

V _S = (R4 / R3 + R4 / R4 + R4 /
R5) × V _DCIN −R4 / R3 × V _ZD For example, R1 = 1000 KΩ, R2 = 30 KΩ, R3 =
100KΩ, R4 = 100KΩ, R5 = 30KΩ, V _ZD
= 13V, when V _AC = 100V, V _S = 8.
It becomes 97 V, and when V _AC = 90 V, V _S = 6.77 V
Becomes This means that a 10% decrease in V _AC results in a 24.5% decrease in V _S. Therefore, the reference DC voltage resistors that constitute the setting circuit 12 R3, R4, and R5 constants, the value of the output voltage V _ZD of the power supply circuit 13, a reference DC voltage corresponding to the voltage V _AC of the variation rate of the commercial power supply V _S can be set to any voltage.

Numeral 14 is a judging means, which is a heat-sensitive part from the heating wire 2.
The alternating current flowing through the material 4 into the sensing wire 3
Temperature / AC voltage characteristic voltage (below
Lower V _TCAbbreviated as) and the relay drive described later.
Output a signal to the circuit. The determination means 14 includes an amplifier circuit 15 and a flat
Mainly consists of a smoothing circuit 16, a comparator circuit 17, and an off-time timer 18.
It is a key component and the other end of the detection line 3 is amplified.
Connected to circuit 15. The amplifier circuit 15 has a V_TCTo amplify
The value is input to the smoothing circuit 16 for rectification and
By sliding it to DC, the temperature and DC voltage characteristic
Pressure (hereinafter V_DCAbbreviated).

The comparator circuit 17 is a comparator element.
Becomes V_DCAnd V_SBy comparing the relay drive circuit
Outputs a signal that turns on and off. That is, the comparison
The output of the smoothing circuit 16 is V_DCAnd the reference voltage
V which is the output of the pressure setting means 10 _SIs input, V_DCIs V_S
Becomes equal to the L level output signal (relay contact
Output signal).

The off-time timer 18 includes a comparator circuit 17
Is for holding the output of the comparator circuit 17 at the L level until a predetermined time elapses after the output signal of becomes the L level, the input terminal is connected to the output side of the comparator circuit 17, and the output terminal Is connected to the input side of the comparator circuit 17.

A relay drive circuit 19 receives the L level output signal of the comparator circuit 17 and receives the relay contact 19a.
Turn off. The relay contact 19a is connected in series with the heating wire 2.

With this structure, the temperature control device operates as follows. First, when the power switch 6 is turned on, a voltage of 100 V is supplied from the commercial power source 7 to the heating wire 2, the heating wire 2 generates heat, and the temperature of the sheet-shaped heat-sensitive heating element 1 rises. When the temperature of the planar heat-sensitive heating element 1 is low, the impedance of the heat-sensitive member 4 is high, so the current flowing from the heat-generating line 2 to the detection line 3 via the heat-sensitive member 4 is small, and the current between the detection lines 3 generated by the current is small. The temperature / AC voltage characteristic voltage V _TC has a small value. Therefore, the amplified output voltage of the amplifier circuit 15 is also small, and the temperature / DC voltage characteristic voltage V _DC converted to DC by the smoothing circuit 16 does not reach the comparison level of the comparator circuit 17, so that the relay contact 19a of the relay drive circuit 19 is connected. Keep the power on and turn off the commercial power
Energization continues from.

When the temperature of the sheet-shaped heat-sensitive heating element 1 rises, the temperature / AC voltage characteristic voltage V _TC between the detection lines 3 also increases.
When the temperature reaches the set value and V _DC becomes equal to V _S ,
The comparator circuit 17 outputs an L level output signal to the relay drive circuit 19, turns off the relay contact 19a, and generates the heating wire 2
Stop energizing to. Therefore, when the heating wire 2 is disconnected from the commercial power supply 7, the temperature
The AC voltage characteristic voltage V _TC disappears and the comparator circuit 17
Tries to stop the output signal of the L level, but the off time timer 18 operates at the time of the last off operation and holds the off operation of the relay drive circuit 19 for a certain period of time, so the relay contact 19a immediately It is not turned on, and is turned on again after a certain cooling time set by the off-time timer 18.
After that, the above operation is repeated, so that the heat-sensitive heating wire 5
Is kept at a constant temperature, and therefore the temperature of the sheet-shaped heat-sensitive heating element 1 is also kept constant.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the reference voltage setting means 20 is composed of a simple circuit, and the description of the common parts with the first embodiment will be omitted.

In the reference voltage setting means 20, one terminal of the resistor R6, which is an impedance element, is connected to the cathode terminal of the diode D2, and the other terminal of the resistor R6 is connected to the anode terminal of the constant current diode CRD. The cathode terminal of the constant current diode CRD is
Connected to circuit ground. Further, a capacitor C2 is provided in parallel between the anode terminal and the cathode terminal of the constant current diode CRD. The constant current diode CRD is an element having a characteristic that a constant current always flows regardless of the magnitude of the voltage applied between the anode terminal and the cathode terminal. Then, the DC voltage generated between both terminals of the constant current diode CRD is input to the comparator circuit 17 as the reference DC voltage V _S.

That is, the voltage V _AC of the commercial power supply 7 is input to the anode terminal of the diode D2, and the diode D2
It is converted into a positive half-wave pulsating flow by 2. Then, the voltage is divided by the resistor R6 and the constant current diode CRD, and smoothed by the capacitor C2 to obtain the reference DC voltage V _S. Further, assuming that the constant current value of the constant current diode CRD is Ip, the voltage V _AC of the commercial power source 7 and the reference DC voltage V _AC
The relation of _S is as follows.

V_S= V_AC× 2^1/2-R6 × Ip For example, when Ip = 1 mA and R6 = 80 KΩ, V
_AC= 100V, V _S= 61.4V, V_AC=
When 90V, V_S= 47.3V. This is
V_ACIs 10% lower, V_SWill be reduced by 23%
That is. Therefore, the constant current of the constant current diode CRD
Depending on the value Ip and the constant value of the resistor R6, V_ACVolatility of
Corresponding to V_SCan be set to any voltage.

That is, even if the voltage of the commercial power source 7 fluctuates, the set temperature of the heat-sensitive heating wire 5 can be prevented from changing significantly.

[0034]

According to the temperature control device of the present invention, since the reference DC voltage V _S drops to an arbitrary voltage in accordance with the rate of decrease of the voltage of the commercial power source, the voltage of the commercial power source has another high capacity. Even if the temperature decreases due to the combined use of electric power equipment, the maximum temperature of the heat-sensitive heating wire does not rise, it is possible to prevent the heat-sensitive member from exceeding the heat-resistant limit temperature, and the preset temperature of the heat-sensitive heating wire can be raised in advance. Therefore, it is possible to provide a planar heating tool with high heating capacity, which improves usability.

In the temperature control device according to the second aspect, the reference DC voltage V _S is output by the commercial power source voltage reading circuit and the reference DC voltage setting circuit, so that the working effect of the first aspect is further promoted. You can

The temperature control device according to claim 3 is the same as that according to claim 1.
In addition to the above effect, the reference DC voltage V _S can be output with a small number of parts, so that the circuit becomes compact.
The device itself can be made compact.

[Brief description of drawings]

FIG. 1 is a block diagram of a temperature control device showing a first embodiment of the present invention.

FIG. 2 is a perspective view of the heat-sensitive heating wire.

FIG. 3 is a circuit diagram of the reference voltage setting means.

FIG. 4 is a circuit diagram of reference voltage setting means of a temperature control device showing a second embodiment of the present invention.

FIG. 5 is a block diagram of a temperature control device showing a conventional example of the present invention.

FIG. 6 is a characteristic diagram of the temperature / AC voltage characteristic voltage V _TC .

FIG. 7 is another characteristic diagram of the temperature / AC voltage characteristic voltage V _TC .

FIG. 8 is a characteristic diagram of impedance of the heat sensitive member.

FIG. 9 is a characteristic diagram of the heat-sensitive heating wire.

[Explanation of symbols]

 1 Planar heat-sensitive heating element 2 Heat-generating wire 3 Detection wire 4 Heat-sensitive member 5 Heat-sensitive heat-generating wire 6 Power switch 7 Commercial power supply 10, 20 Reference voltage setting means 11 Commercial power supply voltage reading circuit 12 Reference DC voltage setting circuit 14 Judging means 17 Comparator circuit 18 Off-time timer 19 Relay drive circuit 19a Relay contact

Claims (3)

[Claims] 1. A line that generates heat when a commercial power source is energized.
Of the heating wire and the sensing wire of the conductor line
Organic heat-sensitive part whose impedance changes negatively according to
Do not arrange the heat-sensitive heating wire formed correspondingly through the material.
The sheet-like heat-sensitive heating element and the heat-generating wire at one end of the heat-sensitive heating wire and the detection wire are short-circuited and rotated.
Use as a road ground and connect the heat generation line to the detection line through the heat sensitive member.
The temperature generated between both ends of the sensing wire by the flowing AC current
Degree / AC voltage characteristic voltage V_TCSignal is output according to the size of
Of the heat generating wire by receiving the signal of the determining means and the determining means.
Control device including a relay drive circuit for controlling
Is set to an arbitrary voltage according to the fluctuation of the commercial power supply voltage.
Reference DC voltage V_SProvided with reference voltage setting means for outputting
At the same time, the determination means determines the temperature / AC voltage characteristic voltage.
V_TCRectified and smoothed temperature / DC voltage characteristic voltage V_DCWhen,
Reference DC voltage V _SAnd are input, and temperature / DC voltage characteristics
Voltage V_DCAnd reference DC voltage V_SRelay drive by comparison of
Comparator circuit that outputs a signal that turns the circuit on and off
A temperature control device comprising: 2. The reference voltage setting means includes a commercial power supply voltage reading circuit that outputs a DC voltage V _DCIN that fluctuates at approximately the same rate as the fluctuation rate of the voltage of the commercial power supply, and a reference DC that amplifies the DC voltage V _DCIN with an operational amplifier. And a reference DC voltage setting circuit for outputting the voltage V _S.
The temperature control device described. 3. The reference voltage setting means is provided with a diode, an impedance element, and a constant current diode in series with a commercial power source, and smoothes a voltage generated between both ends of the constant current diode to smooth the reference DC voltage V. The temperature control device according to claim 1, wherein _S is output.