JPH0197388A - Electric heating apparatus - Google Patents

Abstract

PURPOSE:To substantially uniform temperature range without being affected by outer circumstances so as to enable comfortable temperature controlling by controlling power supply shut-off time according to power supply time count value until a set temperature is obtained. CONSTITUTION:A microcomputer M1 compares detection temperature signal voltage of a heater unit through A/D convertors 12, 11 to a temperature setting voltage by a comparing unit 13, shuts current out to the heater unit by means of a relay driving unit 3 and simultaneously stops the operation of a ON-hour counting unit 14. The energization time is counted and decided by this counting unit 14 until the temperature of the unit reaches a set level, and an OFF time setting unit 15 is controlled according to the energization time. When ambient temperature is low while the energization time is long, the energization OFF period is shortened through an OFF retaining unit 16, and thus the temperature range is substantially kept even to enable comfortable temperature controlling without being affected by outside conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an electric heating device such as an electric carpet.

(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. Since the temperature signal disappears when the power supply to the heater is stopped, the temperature management for the off operation (transition from the on state to the off state) is controlled based on the temperature information from the temperature sensor, and the temperature signal is controlled based on the temperature information from the temperature sensor, Regarding the operation of transitioning from the off state to the on state, boat fishing is controlled for a fixed time using a timer.

In other words, when the temperature of the heater 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 period elapses, an on-off signal is issued and energization to the heater is started.

FIG. 5 shows the configuration of a temperature control circuit of a conventional electric heating device including a timer circuit as described above.
' is the timer circuit. In the figure, after the humidity signal 1 is divided into a predetermined value 1ζ by the resistor R9'PR8' and the variable resistor VR'i, the comparator cp,' compares it with a predetermined value, and the output of the comparator cp,' ) Drive the transistor Tr,', energize the relay Ry' connected to its collector circuit, and turn on/off the relay contact ry' connected between the commercial power source C' and the heater H'. It has become. Note that the set temperature is changed by adjusting the variable resistor VR'.

Further, the timer circuit TIM' is connected to a DC power supply V. 0' and the output terminals of comparators cp and ', and when the output of comparator cp1' becomes low level, that is, when the power supply to heater H' is stopped, power is applied and operation starts. When a predetermined period of time has elapsed, the programmable unijunction transistor PUT' becomes conductive to invert the comparator cp,' through the resistor R6', and energization to the peak H' is restarted.

By the way, in the conventional circuit shown in FIG. 5, the set time of the timer circuit TTM' which sets the off time is constant regardless of the set temperature. As an example, Fig. 6 shows the temporal change in temperature during temperature control of the electric carpeter 1- when the off time is set to 2 minutes. off time t. Temperature range cooled in FF (carpeller) -
The difference in surface temperature between energization on and oat; on-off width (8T1) is large, and when the carpet surface temperature is low as in β, the temperature range △T2 ( It gets smaller.

That is, even if the off time is constant, the on-off width varies depending on the set temperature, resulting in a poor heating feeling.

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 do it either.

(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 to the heater from when the current supply to the heater is stopped until the peak current supply is resumed. It is an object of the present invention to provide an electric heating device which can make the humidity range almost uniform and can perform comfortable temperature control by varying the on-time of energization.

(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.

-4~ In FIG. 1, 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 SW. Further, one end of the altitude detection type gs of the heater unit I is connected to the other end of the heater H1, and the other end of the temperature detection electrode S is connected to the temperature detection section 1. Note that FIG. 2 shows an example of the configuration of the heater unit H.
(A) to (C) are examples constructed in a planar shape, and (D) is an example constructed in a wire shape. In FIG. 2, Hl is a heater, Sl is a temperature detection electrode, Z is a temperature sensor material having 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 a series circuit of a resistor R0°R2 connected in parallel with a heater H1, and a temperature detection electrode S1 is connected to the connection point of the resistors R, , R2. This connection point is connected to the operational amplifier O through resistor R3.
It is connected to the inverting input terminal of P. In addition, the non-inverting input terminal of the operational amplifier OP is connected to the terminal H via a resistor R5.
It is connected to the other end and is also connected to its own output terminal via a resistor R4. The anode of a diode D1 is connected to the output terminal of the operational amplifier OP, and its cathode is connected to the other end of the heater H1 via a capacitor C1 and a resistor R6. It is connected to the.

Therefore, when the heater H1 is energized, a voltage is generated at the temperature detection electrode S due to the current flowing from the heater H through the temperature sensor material Z, and the voltage at the temperature detection electrode S is amplified by the operational amplifier OP1, and the voltage at the temperature detection electrode S is amplified by the operational amplifier OP1. D1. Capacitor C1
The signal is then rectified and input to the control unit 2 as a temperature signal indicating the heater temperature.

Next, the control section 2 has a microcomputer M1 as its main component, and the temperature signal indicating the heater temperature, which is the output of the temperature detection section 1, is sent to the input terminal S1. It is now entered into In addition, an input terminal S1 is used to input a set temperature signal corresponding to the set temperature adjusted by the user.
2 is provided, and a movable terminal of a variable resistor VR, whose both ends are connected between the DC power source v2 and the circuit ground, is connected. The details of the function and operation of the microcomputer M 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, the heater H1 is In addition to the basic function of stopping the energization and controlling the temperature by restarting the energization to the heater H1 by time control after the energization to the heater H1 is stopped, the main part of the present invention is the function of the heater H1. A means for counting the energization time to the heater H1 before the energization to the heater H1 is stopped, and a means for counting the energization time to the heater H1 after the energization to the heater H1 is stopped according to the counted energization time.
A means for changing the time until the power supply is restarted is implemented in software. Note that the signal that controls the energization of the heater H1 is output from the output terminal S. , and is applied to the relay drive unit 3.

Note that Vo, , V, are power supply terminals, and Xl and X2 are terminals for an externally connected resistor R7.

Next, the relay drive section 3 is the output terminal S of the microcombi unit tool M. 1 through a resistor R8, and a relay coil of a relay Ry is inserted into its collector circuit. Note that D2 is a diode for absorbing surges generated in the relay coil.

FIG. 3 shows the functional parts inside the microcomputer M1, which digitizes the temperature signal voltage vA and temperature setting voltage VB inputted from the input terminal 5llj S12, and converts it into a DC power supply V. 0 supplied A/D converter 11.
12 and the output of A/D converter 11゜12,
The output terminal S is configured to stop supplying electricity to the heater H1 when the heater temperature becomes higher than the set temperature. 1, a comparison unit 13 that outputs a signal for controlling the relay drive unit 3, an on-time counting unit 14 that counts the time during which the heater H1 is energized, and a count value of the on-time counting unit 14. Off time setting section 1 that sets off time according to
5 and OFF holding, which keeps the power to the heater H1 off for the off time set by the off time setting section 15 after the power to the heater H1 is turned off, and restarts the power to the heater H1 after the off time has elapsed. It consists of a section 16.

FIG. 4 is a flowchart showing the operation of the microcomputer M related to temperature control in the above embodiment. After making initial settings in step ■, output terminal S is set in step ■. , is set to high level to turn on relay Ry.

In step ■, the temperature setting voltage VB corresponding to the state of the variable resistor VR1 is read, and the A/D converter 12
It is converted into a temperature set value DA2. Also, step ■
Now read the temperature signal voltage VA and convert it to A/D converter 1.
1 to perform A/D conversion and obtain a temperature signal value DA. Further, in step (2), the on-time count section 14 counts the on-time T.

Next, in step (2), the temperature set value DA2 and the temperature signal value DA1 are compared by the comparison unit 13, and DA2>DA,
(If the heater temperature is lower than the set temperature), step ■
If DA2≦DA (the heater temperature is equal to or higher than the set temperature), proceed to step ① and output terminal S. 1 is set to low level to turn off relay Ry. Next, in step (2), after the on time T during which the heater H5 was energized, the off time setting section 15 sets the on time rIRT,
For example, if the heater-off holding time T is 70 seconds or more, set the heater-off holding time T to 80 seconds, and if the on-time T1 is 70 seconds or less, set the value obtained by subtracting the on-time rIIJT from, for example, 50 seconds, that is, T-150-T. , is the setting of the heater-off holding time T.

Next, in step (2), the off time T2 is counted.

Then, when the off time T2 reaches the set beater off holding time T in step 0, the process returns to step (2) and energization of the heater H1 is restarted.

As an example, when the on time T to heater H2 is 5 seconds, the heater off holding time T is 150-50=10
When the heater H1 is set to 0 seconds and the on time T1 to the heater H1 is 70 seconds, the heater OFF holding time T is 150-70=
It is set in 80 seconds. Also, the on time T to the heater H,
is 200 seconds, the heater-off holding time T is 80
seconds.

In other words, even if the set temperature of the heater H1 is constant, the ON time T of the heater H1 will not be constant depending on the usage conditions.For example, if we consider the difference in ambient temperature as the usage environment condition, the heater The on-time T1 to H1 becomes long, and in the present invention, when the on-time T becomes long, the heater-off holding time T is automatically set 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 for heater H1.

becomes small, and the heater-off holding time T is set long; however, since the ambient temperature is high, the decrease in surface temperature is small. 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 current supply to the heater is stopped, and the current supply to the heater is stopped). In the electric heating device, the electricity supply to the heater is restarted by time control after the electricity supply to the heater is stopped. Since the energization stop time changes depending on the surrounding environment, the energization stop time changes depending on the surrounding environment. The temperature difference between the temperature when the power is turned off becomes smaller, and comfortable heating is achieved.

[Brief explanation of the drawing]

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 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, Hl... Heater, Sl
・・・Temperature detection electrode, Z...Fortress sensor material, AC・
・Commercial power supply, Ry ・Relay, ry...Relay contact, 1...Temperature detection section, 2...Control section, 3...
Relay drive unit, Ml...microcomputer and others 1
given name

Claims (3)

[Claims] (1) An electric heating device that stops power supply to the heater when the heater temperature becomes higher than the set temperature, and restarts power supply to the heater under time control after power supply to the heater stops. , a means for counting the time of energization to the heater before the energization to the heater is stopped, and restarting energization of the heater after the energization to the heater is stopped according to the counted energization time. An electric heating device characterized by comprising: means for changing the time until the heating starts. (2) 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.
Electric heating equipment as described in section. (3) The electricity 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. Heating device.