JPH03127477A - Temperature control device - Google Patents

Abstract

PURPOSE:To prevent the opening and the closing at a constant phase by connecting a resistance and a condenser between the output terminals of a temperature setter and a temperature detector, and the input terminal of a comparator. CONSTITUTION:The phases of the ripple wave forms of the output signals from a temperature detector 3 and a temperature setter 4 are different. When two different signals including the ripples synchronous to an AC power source 1 are input to a comparator 7, the AC part of the voltage difference is reduced by a condenser 9, and thereby the phase difference of the ripple wave forms of the output signals from the detector 3 and the setter 4 is eliminated between terminals (a) and (b), and the comparison at the instance of the return of the input signals is not synchronous to the phase of the power source 1. As a result, the phases of the ON and OFF of a relay 11 opened and closed depending on the result of the comparison are not in a constant phase. In such a way, the opening and the closing of the relay at a constant phase can be prevented, and the life of the relay can be extended.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a temperature control device using a relay for electric carpets, floor heating devices, etc.

BACKGROUND OF THE INVENTION A conventional temperature control device is shown in FIG. 3. A heater 13 and a polymer temperature-sensitive material 2 are thermally coupled, and when a polymer temperature-sensitive material is used with direct current, it causes polarization and its performance deteriorates. Since deterioration occurs, current is supplied from an AC power source 1111. The temperature of the heater 13 can be detected by the temperature detection section 3 based on the alternating current flowing through the polymeric temperature-sensitive material 142. Heater 13
When the detected temperature is equal to or higher than the set temperature of the heater 13 determined by *i in the temperature setting section 4, the power supply to the heater 13 is stopped, and when the detected temperature is below the set temperature, the temperature detection section 3 and Electrical signals from the temperature setting section 4 are constantly compared by a comparator 7. The capacitor 14 is for noise absorption between the input terminals of the comparator 7. Electric signals from the temperature detection section 3 and temperature setting section 4 are directly applied to the cutting terminal. The output signal of the comparator 7 is transmitted to the drive circuit 12 of the relay 11 for switching the energization to the heater 13, and the temperature of the heater 13 is controlled.

Problems to be Solved by the Invention However, although the electrical signals from the temperature detection section 3 and the temperature setting section 4 that are input to the comparator 7 are smoothed, they are synchronized with the AC power supply I, and furthermore, the impedance of each circuit is Because they are different, they include ripples with different phases. Comparing signals that have different phases and contain ripples that are synchronized with the power supply, as shown in Figure 4 (a) and (b), the comparison at the moment when the magnitude relationship between the two signals is reversed indicates that they are synchronized with the AC power supply l. This is always done in the same phase, and the inversion of the output of the comparator 7 is also always done in the same phase. Therefore, relay 1
The ON phase and OFF phase of 1 are each constant. When a relay is opened and closed in a constant phase, transition occurs in the relay contacts, which significantly shortens the life of the relay.

The present invention solves the above problem, and instead of using a comparator to compare signals with different phases, synchronized with the power supply, or containing samples, the present invention reduces the phase difference between the two signals. Temperature control that extends relay life by not comparing the moment when the signal magnitude relationship is reversed in synchronization with the AC power supply, and by preventing the ON and OFF phases of the relays being opened and closed from becoming constant phases. A control device is provided.

Means for Solving the Problems In order to solve the above problems, the temperature control device of the present invention includes an AC power source, a heater, a relay for controlling energization to the heater, and a high temperature control device thermally coupled to the heater. a molecular temperature-sensitive material, a temperature setting section that sets the temperature of a heater, a temperature detection section that detects an alternating current flowing through the polymer temperature-sensitive material, and a comparator that compares voltages of the temperature setting section and the temperature detection section. and,
a first resistor connected in series between one input terminal of the comparator and the output terminal of the temperature setting section; a second resistor connected between the output terminal of the first resistor and the output terminal of the first resistor;
A first capacitor connected between the comparator side of the resistor and the comparator side of the second resistor, and between the temperature setting section side of the first resistor and the temperature detection section side of the second resistor. A second capacitor connected to the comparator, a relay drive section for opening and closing the relay according to the output of the comparator, and a smoothing circuit for supplying direct current to the coil of the relay.

Effect With the above configuration, the impedance to the AC component between the input terminals of the comparator becomes small due to the action of the 1.2 capacitor and the 1.2 resistor, so that the output signal of the temperature detection section input to the comparator and The AC voltage difference between the output signals of the temperature setting unit can be made very small. The ripple waveforms are in phase, and the inverted phase of the signal input to the comparator is not synchronized with the phase of the AC power supply. Therefore, the ON and OFF phases of the relays, which are opened and closed by the output of the comparator, are in constant phase. This will be prevented.

Example Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram using a temperature control device showing one embodiment of the present invention. In FIG. 1, 1 is an AC power source, 13 is a heater, and 2 is a polymer temperature-sensitive material that is thermally coupled to the heater 13, and is directly supplied with current from the AC power source 1.

The polymer temperature-sensitive material 2 is connected to an input terminal of a temperature detection section 3, and an output terminal of the temperature detection section 3 is connected to a resistor 5 connected in series to one input terminal of a comparator 7. The output terminal of the temperature setting section 4 is connected to the other input terminal of the comparator 7 via a resistor 6 connected in series.

A capacitor 8 with a capacitance of 0.5 μF or more is connected between the input terminals of the comparator 7, and a capacitor 9 of the same type as the capacitor 8 is connected between the resistor 5 and the temperature detection circuit 3, and between the resistor 6 and the temperature setting. It is connected between the part 7 and the connecting part.

A relay 1ivl operating circuit 12 is connected to the output terminal of the comparison 2S1. One end of the coil of the relay 11 is connected to the AC current tA1 via the smoothing circuit 10, and the other end is connected to the relay drive circuit I2.

Next, the operation of the configuration of this embodiment will be explained. The temperature of the heater 13 is detected by the temperature detecting section 3 from the alternating current JR current flowing through the polymeric temperature-sensitive material 2 .

Although the detected signal is smoothed, it contains ripples. The phase of the ripple waveform is synchronized with the phase of AC type R1. Similarly, the output signal from the temperature setting section 4 is also
Although it includes a ripple synchronized with the X power supply 1, the phase of the ripple waveform is different from the phase of the ripple waveform of the output signal of the temperature detection section 3 because the circuit impedance of the temperature detection section 3 and the temperature setting section 4 is different. There are different. When two different signals with different phases and including ripple synchronized with the AC power supply are input, the AC component of the voltage difference is reduced by the capacitor 9 installed in the human power section of the comparator.
There is no phase difference between the ripple waveforms of the output signals of the temperature detection section 3 and the temperature setting section 4 between the terminals a and b. Therefore, as shown in FIGS. 2(al) and 2(b), the comparison at the moment when the input signal is inverted is not synchronized with the phase of the AC power supply 1.Therefore, the ON and OFF of the relay 11, which is opened and closed depending on the comparison result, is not synchronized with the phase of the AC power supply 1.
The phase of is never constant.

The larger the capacitance value of the capacitor 9, the smaller the phase difference between the ripple waveforms of the output signals of the temperature detection section 3 and temperature setting section 4 between terminals a and b. However, if the capacitance value is too large, The response of the comparator 7 is delayed with respect to temperature changes, and the output signal of the comparator 7 oscillates. Furthermore, there is a limit to increasing the capacitance of the capacitor 9 in consideration of the miniaturization of equipment and the like. Therefore, the potential difference between terminals a and b is determined by resistor 5.
By further dividing the voltage by the capacitor 6 and the capacitor 8, the potential difference between the input terminals of the comparator 7 can be made very small without increasing the capacitance value of the capacitor 9.

Effects of the Invention As described above, according to the present invention, in a temperature control device using a relay, it is possible to prevent the relay from opening and closing in a constant phase with an extremely simple circuit configuration, and it has a great effect on extending the life of the relay. It is something that demonstrates the.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a temperature control device according to an embodiment of the present invention, and FIG. 2 is a voltage waveform diagram of the temperature detection section and reference temperature setting section voltages at the comparator input terminal in the same temperature control device.
a) is a voltage waveform diagram when the relay is ON, (1)) is a voltage waveform diagram when the relay is OFF, Figure 3 is a circuit diagram of a conventional temperature control device, and Figure 4 is a diagram of a conventional temperature control circuit. This is a voltage waveform diagram of the temperature detection part and reference temperature setting part voltage at the comparator input terminal, (al is a voltage waveform diagram when the relay is ON, and wa) is a voltage waveform diagram when the relay is OFF. [...AC power supply, 2...Polymer temperature-sensitive material, 3...Temperature detection section, 4...Temperature setting section, 5.6... ...Resistance, 7...Comparator,
8.9... Capacitor, lO... Smoothing circuit, 11... Relay, 12... Relay drive circuit, 13... Heater.

Claims (1)

[Claims] an AC power source, a heater, a relay for controlling energization to the heater, a polymeric temperature-sensitive material thermally coupled to the heater, a temperature setting section for setting the temperature of the heater, and the polymeric temperature-sensitive material. a temperature detection unit that detects alternating current flowing through the material;
a comparator that compares the voltages of the temperature setting section and the temperature detection section; a first resistor connected in series between one input terminal of the comparator and an output terminal of the temperature setting section; and this resistor. a second resistor having the same resistance value and connected between the other input terminal of the comparator and the output terminal of the temperature detection section, and a comparator side of the first resistor and a comparator of the second resistor. and a second capacitor connected between the temperature setting section side of the first resistor and the temperature detection section side of the second resistor.
A temperature control device comprising: a capacitor; a relay drive unit for opening and closing the relay according to the output of the comparator; and a smoothing circuit for supplying direct current to the coil of the relay.